BEGIN:VCALENDAR
VERSION:2.0
PRODID:researchseminars.org
CALSCALE:GREGORIAN
X-WR-CALNAME:researchseminars.org
BEGIN:VEVENT
SUMMARY:Christoph Kawan (LMU München\, Germany)
DTSTART:20210708T150000Z
DTEND:20210708T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/1
DESCRIPTION:Title: A Lyapunov-based small-gain approach to ISS of infinite nonlinea
r networks\nby Christoph Kawan (LMU München\, Germany) as part of Inp
ut-to-State Stability and its Applications\n\n\nAbstract\nIn this talk\, I
present an approach to the verification of\ninput-to-state stability for
networked control systems composed of a\ncountably infinite number of nonl
inear subsystems. The essential\nrequirements on these subsystems are that
they are finite-dimensional\,\ncontinuous in time and each of them is inf
luenced only by finitely many\nother subsystems. Assuming that each subsys
tem admits an ISS Lyapunov\nfunction with respect to both internal inputs
(influences from other\nsubsystems) and external inputs (control inputs)\,
our result provides\nsufficient conditions for the existence of an ISS Ly
apunov function for\nthe whole network. This Lyapunov function is built fr
om the Lyapunov\nfunctions of the subsystems and it is important to note t
hat the ISS\nestimates for the later are given in the max-type formulation
. This\nformulation allows for the definition of an associated max-type ga
in\noperator Gamma\, encoding the influence of the\nsubsystems on each oth
er via nonlinear gain functions. The operator\nGamma acts as a monotone op
erator on the positive cone of \\ell_{\\infty}.\nThe essential requirement
on Gamma is that it admits a so-called path of\nstrict decay\, a conditio
n which is known to be equivalent to the\nclassical small-gain condition i
n the case of finite networks. For\ninfinite networks\, however\, this equ
ivalence does not hold. Still\, as in\nfinite dimensions\, the existence o
f a path of strict decay is linked to\nthe stability properties of the dis
crete-time system generated by the\ngain operator. In my talk\, I will try
to\nexplain the difficulties involved with the stability analysis of this
\nsystem.\n\nJoint work with Andrii Mironchenko and Majid Zamani\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Iasson Karafyllis (National Technical University of Athens\, Greec
e)
DTSTART:20210715T150000Z
DTEND:20210715T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/2
DESCRIPTION:Title: IOS-gains and asymptotic gains for linear systems\nby Iasson
Karafyllis (National Technical University of Athens\, Greece) as part of
Input-to-State Stability and its Applications\n\n\nAbstract\nThe talk will
be devoted to the presentation of a fundamental relation between Output \
nAsymptotic Gains (OAG) and Input-to-Output Stability (IOS) gains
for linear \nsystems. More specifically\, it will be shown that f
or every Input-to-State Stable\, \nstrictly causal linear system the mi
nimum OAG is equal to the minimum IOS-gain. \nMoreover\, both quantities
can be computed by solving a specific optimal control \nproblem
and by considering periodic inputs only. The result is valid for wide clas
ses \nof linear systems (including delay systems or systems descri
bed by PDEs). The \ncharacterization of the minimum IOS-gain is i
mportant because it allows the non-\nconservative computation of t
he IOS-gains\, which can be used in a small-gain \nanalysis. A n
umber of cases of finite-dimensional linear systems will also be
\npresented\, where exact computation of the minimum IOS-gain can
be performed. \nLinks to notions used extensively in the literature of l
inear systems (e.g.\, the BIBO \nnorm or the notion of an admissible opera
tor) will be provided.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Miroslav Krstic (UC San Diego\, USA)
DTSTART:20210722T150000Z
DTEND:20210722T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/3
DESCRIPTION:Title: Fixed-Time ISS and Prescribed-Time Stabilization\nby Mirosla
v Krstic (UC San Diego\, USA) as part of Input-to-State Stability and its
Applications\n\n\nAbstract\nIn prescribed-time stabilization the task is t
o design a feedback law that guarantees completion of the convergence to a
set point no later than a time that is prescribed by the user and indepen
dent of the initial condition of the plant. When the plant model is known
perfectly and the full state is measured\, ISS issues do not arise. Howeve
r\, in the presence of disturbances or under observer-based feedback\, ISS
with respect to various inputs becomes of interest. Perhaps unexpectedly\
, once prescribed-time stabilization is achieved\, an ISS-like property st
ronger than the conventional ISS is obtained as a bonus. Specifically\, th
e origin\, which is not necessarily the system’s equilibrium\, is made a
ttractive in prescribed time even in the presence of non-vanishing disturb
ances. Or\, in simpler language\, the ISS gain is a function of time and d
ecays to zero at the terminal time. I will discuss the ISS issues associat
ed with prescribed-time feedback design for general linear ODEs\, some non
linear ODEs with a disturbance matched by control\, and briefly for parabo
lic PDEs (in hyperbolic PDEs\, finite-time stabilization\, when possible\,
is obtained as easily as exponential stabilization).\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Romain Postoyan (CNRS\, Université de Lorraine\, France)
DTSTART:20210729T150000Z
DTEND:20210729T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/4
DESCRIPTION:Title: Event-Triggered Control Through the Eyes of Hybrid Small-Gain Th
eorem\nby Romain Postoyan (CNRS\, Université de Lorraine\, France) as
part of Input-to-State Stability and its Applications\n\n\nAbstract\nA co
mmon approach to design event-triggered controllers is emulation. The idea
is to first construct a feedback law in continuous-time\, which ensures t
he desired closed-loop properties. Then\, the communication constraints be
tween the plant and the controller are taken into account and a triggering
rule is synthesized to generate the transmission instants in such a way t
hat the properties of the continuous-time closed-loop system are preserved
\, and a strictly positive minimum inter-event time exists\, which is esse
ntial in practice.\n\nVarious triggering rules have been proposed in this
context in the literature\, including relative threshold\, fixed threshold
\, dynamic triggering law to mention a few. We will show in this talk that
these seemingly unrelated techniques can all be interpreted in a unified
manner. Indeed\, it appears that all them guarantee the satisfaction of th
e conditions of a hybrid small-gain theorem. This unifying perspective pro
vides clear viewpoints on the essential differences and similarities of ex
isting event-triggering policies. Interestingly\, for all the considered l
aws\, the small-gain condition vacuously holds in the sense that one of th
e interconnection gains is zero. We then exploit this fact to modify the o
riginal triggering law in such a way that the small-gain condition is no l
onger trivially satisfied. By doing so\, we obtain redesigned strategies\,
which may reduce the number of transmissions as illustrated by an example
.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrey Polyakov (Inria Lille Nord-Europe / CNRS CRIStAL)
DTSTART:20211007T150000Z
DTEND:20211007T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/6
DESCRIPTION:Title: On Input-to-State Stability of Homogeneous Evolution Equations\nby Andrey Polyakov (Inria Lille Nord-Europe / CNRS CRIStAL) as part of
Input-to-State Stability and its Applications\n\n\nAbstract\nHomogeneity
is a symmetry of an object with respect to a dilatation. All linear and ma
ny\nnonlinear models of mathematical physics are homogeneous. For example\
, Burgers\, KdV and Navier-Stokes \nequations are symmetric with respect t
o a properly selected dilation. Finite dimensional homogeneous control\ns
ystems are known to be similar with linear ones\, but they may have a bet
ter regulation quality like\na faster convergence\, stronger robustness a
nd less overshoot. This talk is devoted to Input-to-State Stability analys
is\nof homogeneous evolution equations in Banach spaces. Similarly to the
finite-time dimensional case\, it is shown that\nthe uniform asymptotic st
ability of homogeneous unperturbed system guarantees its Input-to-State St
ability\nwith respect to homogeneously involved perturbations.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Antoine Chaillet (L2S - CentraleSupélec - Univ. Paris Saclay)
DTSTART:20211028T150000Z
DTEND:20211028T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/7
DESCRIPTION:Title: Point-wise dissipation in time-delay systems: recent results and
open questions\nby Antoine Chaillet (L2S - CentraleSupélec - Univ. P
aris Saclay) as part of Input-to-State Stability and its Applications\n\n\
nAbstract\nIn the existing characterizations of input-to-state stability (
ISS) for time-delay systems\, the Lyapunov-Krasovskii functional (LKF) has
a $\\mathcal K_\\infty$ dissipation rate that involves the whole LKF itse
lf (LKF-wise dissipation) or even the supremum norm of the state history (
history-wise dissipation). A similar characterization holds for integral i
nput-to-state stability (iISS)\, in which the dissipation rate is just a p
ositive definite function. These characterizations have allowed to extend
several results on ISS and iISS from finite dimension to time-delay system
s.\n\nNevertheless\, in practice\, obtaining a LKF-wise or history-wise di
ssipation is not always an easy task and often resorts to rather artificia
l tricks. More crucially\, in the absence of inputs\, it is known from the
work of N. Krasovskii that a dissipation involving merely the current val
ue of the state norm (point-wise dissipation) is enough to guarantee globa
l asymptotic stability.\n\nIn this talk\, we investigate whether a point-w
ise dissipation suffices to conclude ISS or iISS for time-delay systems. W
e give a positive answer to this question for iISS. More precisely\, we sh
ow that point-wise\, LKF-wise and history-wise dissipations through a posi
tive definite function all ensure iISS. \n\nFor ISS\, despite strong effor
ts\, this question remains open: it has not yet be proved or disproved tha
t ISS is equivalent to the existence of a point-wise dissipation. We ident
ify two classes of systems for which this is the case\, by imposing a grow
th restriction either on the upper bound of the LKF or on the vector field
. We also provide some insights on what can be said about a system having
a point-wise dissipation to hopefully foster some creative discussion.\n\n
Finally\, while asymptotic stability is known for long to be equivalent to
a point-wise dissipation for input-free systems\, this question remains o
pen for exponential stability. We show that\, at least for systems ruled b
y a globally Lipschitz vector field\, global exponential stability is guar
anteed under a point-wise dissipation.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:No Seminar this week\, but consider taking part in the SCINDIS Wo
rkshop (27-29 Sep 2021\, fully online\, zero conference fee)
DTSTART:20210930T150000Z
DTEND:20210930T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/8
DESCRIPTION:Title: 3rd Workshop on Stability and Control of Infinite-Dimensional Sy
stems (SCINDIS 2020)\nby No Seminar this week\, but consider taking pa
rt in the SCINDIS Workshop (27-29 Sep 2021\, fully online\, zero conferen
ce fee) as part of Input-to-State Stability and its Applications\n\n\nAbst
ract\nVisit the homepage of SCINDIS:\nhttps://www.fan.uni-wuppertal.de/de/
scindis-2020.html\n\nThe scope of the Workshop includes but is not limited
to\n \n >Stability and control of partial differential equations\n >St
ability and control of time-delay systems\n >Input-to-state stability of
infinite-dimensional systems\n >Stabilizability of infinite-dimensional s
ystems\n >Semigroup and admissibility theory\n\nOrganizers:\nSergey Dashk
ovskiy\nBirgit Jacob \nAndrii Mironchenko\nFabian Wirth\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rami Katz (Tel-Aviv University\, Israel)
DTSTART:20211209T160000Z
DTEND:20211209T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/10
DESCRIPTION:Title: Finite-dimensional observer-based ISS and $L^2$-gain control of
parabolic PDEs\nby Rami Katz (Tel-Aviv University\, Israel) as part o
f Input-to-State Stability and its Applications\n\n\nAbstract\nFinite-dime
nsional observer-based controller design for PDEs is a challenging problem
. In this talk\, construction of such controllers via the modal decomposit
ion method for linear parabolic 1D PDEs will be presented. We will start w
ith finite-dimensional observer-based control for the linear heat equation
where at least one of the control or observation operators is bounded. We
will proceed with the case of both operators unbounded\, where dynamic ex
tension is helpful. Here we will consider ISS and $L^2$-gain analysis of t
he Kuramoto-Sivashinsky equation. The extension of the results to time-var
ying input/output delays\, as well as arbitrarily large constant input del
ays will be presented. Finally\, we will discuss sampled-data implementati
on of finite-dimensional boundary controllers for the 1D heat equation un
der discrete-time point measurement\, via a generalized hold device. An es
sential tool for the ISS analysis will be a novel ISS Halanay’s inequali
ty with explicit constants in the bounds.\n\nJoint work with Prof. Emilia
Fridman\nhttps://scholar.google.co.il/citations?user=szPJQlkAAAAJ&hl=en\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Felix Schwenninger (TU Twente\, the Netherlands)
DTSTART:20211202T160000Z
DTEND:20211202T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/11
DESCRIPTION:Title: Recent results on ISS Lyapunov functions\nby Felix Schwenni
nger (TU Twente\, the Netherlands) as part of Input-to-State Stability and
its Applications\n\n\nAbstract\nLike in many branches of dynamical system
s\, Lyapunov functions play a pivotal role in the study of input-to-state
stability.\nIn this talk we discuss recent investigations around such coer
cive and non-coercive Lyapunov functions in the context of infinite-dimens
ional systems. A focus is laid on general linear PDEs subject to boundary
control.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ricardo Sanfelice (University of California\, Santa Cruz\, USA)
DTSTART:20211118T160000Z
DTEND:20211118T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/12
DESCRIPTION:Title: Observers for Hybrid Dynamical Systems: Models\, Necessary Cond
itions\, and Systematic Design\nby Ricardo Sanfelice (University of Ca
lifornia\, Santa Cruz\, USA) as part of Input-to-State Stability and its A
pplications\n\n\nAbstract\nIn most control applications\, estimating the s
tate of a system is crucial\, whether it be for control\, supervision\, or
fault diagnosis purposes. Unfortunately\, the problem of designing observ
ers for systems with state variables that evolve continuously\, and at tim
es\, jump -- namely\, hybrid systems -- in a general setting is unsolved.
One of the main challenges in the design of observers for such systems is
the fact that hybrid behavior may lead to system trajectories from nearby
initial conditions that have different jump times. Such a mismatch of jum
p times makes the formulation of observability/detectability and\, in turn
\, observer design very challenging. After a brief introduction to hybrid
dynamical systems\, recent advancements towards the systematic design of
observers for hybrid systems will be presented. Specifically\, a general
framework for state estimation of plants modeled as hybrid dynamical syst
ems\, both in the favorable case where the jumps of the plant and of the o
bserver occur at the same time and when they occur at different (but nearb
y) times\, will be introduced. With a suitable notion of observer for hyb
rid dynamical systems and relying on reparameterizations of the hybrid sig
nals involved\, it will be shown that an appropriate detectability notion
is necessary for the existence of an observer\, or better said\, a hybrid
observer. Applications and examples will be presented to illustrate the c
oncepts and results. This research is joint work with Professor Pauline B
ernard at MINES ParisTech (https://sites.google.com/site/sitepmbernard/hom
e).\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aneel Tanwani (LAAS-CNRS\, Toulouse\, France)
DTSTART:20220113T160000Z
DTEND:20220113T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/13
DESCRIPTION:Title: Input-to-State Stability of Switched Systems under Dwell-Time C
onditions\nby Aneel Tanwani (LAAS-CNRS\, Toulouse\, France) as part of
Input-to-State Stability and its Applications\n\n\nAbstract\nAbstract: St
ability analysis of switched systems has been a topic of interest for more
than two decades\, and the conditions based on dwell-time notions form an
important part of this literature. In particular\, input-to-state stabili
ty (ISS) and different variants of ISS have also been studied using simila
r dwell-time conditions on the switching signals. Earlier approaches in th
is direction\, based on multiple Lyapunov functions\, typically require ex
ponentially decaying Lyapunov functions which are compatible with other su
bsystems. However\, such compatibility may not hold for switched nonlinear
systems in general\, where the individual Lyapunov functions admit nonlin
ear supply functions. In this talk\, I will start with a quick overview of
earlier results on ISS using dwell-time conditions. Then\, I will provide
some examples of switched nonlinear systems which are not ISS for arbitra
rily large values of dwell-time\, even though individual subsystems are IS
S. Nevertheless\, under certain conditions on Lyapunov functions (which ad
mit nonlinear supply functions)\, we can derive new dwell-time bounds\, wh
ich guarantee ISS of switched systems. We will see the utility of such con
ditions in analyzing stability of cascade interconnections of switched sys
tems and an application in sampled-data control using dynamic output feedb
ack.\n\nReferences:\n[1] M. Della Rossa and A. Tanwani. Instability of Dwe
ll-Time Constrained Switched Nonlinear Systems. Under review in Systems &
Control Letters\, June 2021. Preprint available on request.\n[2] S. Liu\,
A. Tanwani and D. Liberzon. ISS and Integral ISS of Switched Systems with
Nonlinear Supply Functions. Mathematics of Controls\, Signals\, and System
s\, 2021. DOI: 10.1007/s00498-021-00306-x\n[3] G.X. Zhang and A. Tanwani.
ISS Lyapunov Functions for Cascade Switched Systems and Sampled-Data Contr
ol\, Automatica\, 105: 216—227\, 2019.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pierdomenico Pepe (University of L'Aquila)
DTSTART:20220120T160000Z
DTEND:20220120T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/14
DESCRIPTION:Title: Nonlinear Halanay's Inequalities for ISS of Retarded Systems: t
he Continuous and the Discrete Time Case\nby Pierdomenico Pepe (Univer
sity of L'Aquila) as part of Input-to-State Stability and its Applications
\n\n\nAbstract\nNonlinear versions of continuous-time and discrete-time Ha
lanay's inequalities are presented as sufficient conditions for the conver
gence of involved functions to the origin\, uniformly with respect to boun
ded sets of initial values. The same results are shown in the case forcing
terms are also present\, for the uniform convergence to suitable neighbor
hoods of the origin. Related Lyapunov methods for the global uniform asymp
totic stability and the input-to-state stability of systems described by r
etarded functional differential equations and by discrete-time equations w
ith delays are shown. \n\nReferences:\n[1] Pierdomenico Pepe\, A Nonlinear
Version of Halanay’s Inequality for the Uniform Convergence to the Orig
in\, Mathematical Control and Related Fields\, 2021\, doi: 10.3934/mcrf.
2021045\n\n[2] Maria Teresa Grifa\, Pierdomenico Pepe\, On Stability Analy
sis of Discrete-Time Systems With Constrained Time-Delays via Nonlinear Ha
lanay-Type Inequality\, IEEE Control Systems Letters\, Volume 5\, Issue 3\
, July 2021\, doi: 10.1109/LCSYS.2020.3007096\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wilfrid Perruquetti (Ecole Centrale de Lille\, CNRS\, France)
DTSTART:20220203T160000Z
DTEND:20220203T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/15
DESCRIPTION:Title: Non-Asymptotic output feedback of a double integrator: a separa
tion principle.\nby Wilfrid Perruquetti (Ecole Centrale de Lille\, CNR
S\, France) as part of Input-to-State Stability and its Applications\n\n\n
Abstract\nUsually\, in control/estimation problems\, one is looking at exp
onential decaying rates for many reasons: ease of understanding\, many too
ls for tuning and getting a time response estimate. But nowadays\, control
theory has to meet more and more demanding performances in many areas suc
h as aerospace\, manufacturing\, robotics and transportation to mention a
few. A necessary property for these algorithms is stability. The convergen
ce time for the system to reach the goal may be infinite (e.g.\, asymptoti
c or exponential convergence) or finite. Combining stability with these co
nvergence types leads to asymptotic or non-asymptotic stability properties
. \n\nThese concepts may help in obtaining a separation principle when des
igning output feedback as seen on an example for an double integrator syst
em where ISS properties of homogeneous systems is applied without building
a Lyapunov function for the closed-loop system.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chris Guiver (Edinburgh Napier University)
DTSTART:20220210T160000Z
DTEND:20220210T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/16
DESCRIPTION:Title: The exponential input-to-state stability property — character
isations and feedback interconnections\nby Chris Guiver (Edinburgh Nap
ier University) as part of Input-to-State Stability and its Applications\n
\n\nAbstract\nThe exponential input-to-state stability (ISS) property is c
onsidered for systems of controlled nonlinear differential equations\, and
a characterisation in terms of an exponential ISS Lyapunov function is es
tablished. A natural concept of linear state/input-to-state L2-gain is\nin
troduced\, and the equivalence of this property and exponential ISS is est
ablished. Further\, the feedback interconnection of two exponentially ISS
systems is shown to be exponentially ISS provided a suitable small-gain co
ndition is satisfied.\n\nJoint work with Hartmut Logemann\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lars Grüne (University of Bayreuth)
DTSTART:20230531T150000Z
DTEND:20230531T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/17
DESCRIPTION:Title: Curse-of-dimensionality-free computation of (control-)Lyapunov
functions via ISS small-gain techniques and neural networks\nby Lars G
rüne (University of Bayreuth) as part of Input-to-State Stability and its
Applications\n\n\nAbstract\nThe literature reports a large number of comp
utational methods for Lyapunov and control Lyapunov functions. For most of
these approaches the computational effort grows exponentially in the stat
e space dimension\, making them infeasible even for moderately high-dimens
ional problems. In this talk we show that this so-called curse of dimensio
nality can be overcome for Lyapunov functions with a suitable separable st
ructure\, as they are provided by ISS small-gain theory.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fabian Wirth (University of Passau\, Germany)
DTSTART:20230614T150000Z
DTEND:20230614T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/18
DESCRIPTION:Title: Variants of Two-Measure Input-to-State Stability\nby Fabian
Wirth (University of Passau\, Germany) as part of Input-to-State Stabilit
y and its Applications\n\n\nAbstract\nThis talk is based on joint work wit
h Christopher Kellett\n\nThis talk concerns finite-dimensional systems des
cribed by ordinary differential equations with inputs.\nFor attracting clo
sed sets that are not compact we consider different formulations of input-
to-state stability properties and related Lyapunov criteria. In the compac
t case\, there exists a well-established hierarchy of such properties and
some formulations have been quickly discarded as equivalent to input-to-s
tate stability. In the noncompact case\, however\, several new phenomena
appear. In particular\, input-to-state stability (ISS) does not imply inte
gral input-to-state stability\, and ISS is not equivalent to integral-inpu
t-to-integral-state stability. The criteria are formulated in terms of mea
surement functions\, which allows a uniform presentation of a number of re
lated results. Some examples are discussed to show some of the phenomena t
hat may occur.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christophe Prieur (CNRS\, University Grenoble Alpes\, France)
DTSTART:20230621T150000Z
DTEND:20230621T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/19
DESCRIPTION:Title: Boundary feedback stabilization of freeway traffic networks: IS
S control and experiments\nby Christophe Prieur (CNRS\, University Gre
noble Alpes\, France) as part of Input-to-State Stability and its Applicat
ions\n\n\nAbstract\nBoundary feedback control of networks of freeway traff
ic is considered in this talk by means of\nPartial Differential Equations
based techniques and Lyapunov theory. The control and measurements are all
located at the boundaries of each link. In this talk we will study some p
ublished and on-going works on the control of these dynamics and on the de
sign problem of boundary controls ensuring an Input-to-State Stability pro
perty in presence of disturbances. Finally some results will be illustrate
d using a traffic simulation software at the Fourth Ring road of Beijing\,
China when some specific traffic data are collected and the sufficient co
nditions for the stability are checked.\n\nBiography: Christophe PR
IEUR graduated in Mathematics from the Ecole Normale Supérieure de Cachan
\, France in 2000. He received the Ph.D degree in 2001 in Applied Mathemat
ics from the Université Paris-Sud\, France. From 2002 he was an associate
researcher CNRS at the laboratory SATIE\, Cachan\, France\, and at the LA
AS\, Toulouse\, France (2004-2010). In 2010 he joined the Gipsa-lab\, Gren
oble\, France where he is currently a senior researcher of the CNRS (since
2011). He was the Program Chair of the 9th IFAC Symposium on Nonlinear Co
ntrol Systems (NOLCOS 2013)\, the 14th European Control Conference (ECC 20
15) and the 61st IEEE Conference on Decision and Control (CDC 2022). He is
currently an associate editor of the AIMS Evolution Equations and Control
Theory\, the SIAM Journal of Control and Optimization and the Mathematics
of Control\, Signals\, and Systems. He is a senior editor of the IEEE Con
trol Systems Letters\, and an editor of the IMA Journal of Mathematical Co
ntrol and Information. His current research interests include nonlinear co
ntrol theory\, hybrid systems\, and control of partial differential equati
ons\, with applications including navigation and object tracking\, fluid d
ynamics\, and fusion control. He is an IMA Fellow\, and an IEEE Fellow.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:José Luis Mancilla-Aguilar (Universidad de Buenos Aires\, Argenti
na)
DTSTART:20230607T150000Z
DTEND:20230607T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/20
DESCRIPTION:Title: From ISS to iISS without the use of Lyapunov functions: a diffi
cult path leading to greater generality\nby José Luis Mancilla-Aguila
r (Universidad de Buenos Aires\, Argentina) as part of Input-to-State Stab
ility and its Applications\n\n\nAbstract\nIt is well-known that input-to-s
tate (ISS) stability implies integral ISS (iISS) for time-invariant finite
dimensional systems. The original proof of this fact is heavily based on
the existence of an ISS dissipation-form Lyapunov function. When one tries
to prove the implication for time-varying systems two obstacles appear: a
) there are ISS systems that are not iISS and b) existing converse theorem
s provide ISS implication-form Lyapunov functions that may not be necessar
ily dissipation-form ones. In this presentation we talk about the way we
found for proving that ISS implies iISS avoiding the use of Lyapunov funct
ions and how this allows us to prove that implication for other types of t
ime-varying systems\, such as impulsive and switched systems. We also pres
ent a characterization of iISS\, which holds even for axiomatically define
d systems\, that was crucial in our approach for proving that ISS is stron
ger than iISS under suitable hypotheses. \n\nIt is joint work with Hernan
Haimovich and Jose Esteban Rojas-Ruiz.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marius Tucsnak (Université de Bordeaux\, France)
DTSTART:20230628T150000Z
DTEND:20230628T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/21
DESCRIPTION:Title: ISS type properties of some fluid dynamics systems\nby Mari
us Tucsnak (Université de Bordeaux\, France) as part of Input-to-State St
ability and its Applications\n\n\nAbstract\nWe consider systems describing
viscous fluid flows\, possibly in interaction with rigid bodies\, moving
at the interior or floating on the free surface of the fluid. We briefly p
resent the case when the fluid is contained in a bounded container. Exploi
ting the exponential stability of the linearized system we show that in th
is case we can obtain ISS type estimates for fully nonlinear problems. The
focus is on the case when the fluid fills the whole space (with the possi
ble exception of a bounded moving rigid body). In this case the linearized
system is not exponentially and not even polynomially stable. In this c
ase we prove a nonstandard type of ISS estimates for the linearized system
s. We finally explain how to obtain wellposedness results for fully nonli
near fluid-structure interaction in unbounded domains and formulate some c
onjectures on the ISS properties of these systems.\n\nBiography: Ma
rius Tucsnak is Professor of Mathematics of the University of Bordeaux in
France. He holds a Master degree in mathematics from the University of Buc
arest\, Romania and a Ph.D. degree from the University of Orléans\, Franc
e (1992). In 1995 he obtained his Habilitation pour Diriger les Recherches
from the “Université Pierre et Marie Curie”\, Paris. In 1992 he beca
me Associate Professor of Mathematics at the University of Versailles\, Fr
ance. In 1997 he became full professor of mathematics at the University of
Nancy\, France. He moved to University of Bordeaux in 2015. \nHe was an i
nvited speaker to the International Congress of Mathematicians (ICM)\, 202
2\, and since 2013 he is a Member of Institut Universitaire de France (IUF
). \nHis fields of expertise are the analysis and the control of systems g
overned by partial differential equations. One of his major recent contrib
utions is his participation at a series of works which solved a long stand
ing open problem: the full characterization of the reachable space for the
boundary controlled one dimensional heat equation.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Swann Marx (CNRS\, Nantes\, France)
DTSTART:20230524T150000Z
DTEND:20230524T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/22
DESCRIPTION:Title: ISS Lyapunov functional strictification for the output regulati
on of a Korteweg-de Vries equation\nby Swann Marx (CNRS\, Nantes\, Fra
nce) as part of Input-to-State Stability and its Applications\n\n\nAbstrac
t\nThis talk will be about the construction of a strict ISS Lyapunov funct
ional in order to design a controller achieving an output regulation task
for a Korteweg-de Vries equation. To be more precise\, our goal is to add
an integrator so that one is able to make converging a given output to a d
esired reference. To do so\, a forwarding method will be used together wit
h the construction of a ISS strict Lyapunov functional\, that is necessary
to apply the above mentioned method. The strictification technique is bas
ed on a recent method\, developed in the finite-dimensional context by Lau
rent Praly\, and that relies on the construction of an observer. In our co
ntext\, this observer is built thanks to the backstepping method. It is jo
int work with Ismaïla Balogoun and Daniele Astolfi.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sergey Dashkovskiy (University of Würzburg\, Germany)
DTSTART:20230705T150000Z
DTEND:20230705T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/23
DESCRIPTION:Title: Interconnected systems with possibly unstable subsystems\nb
y Sergey Dashkovskiy (University of Würzburg\, Germany) as part of Input-
to-State Stability and its Applications\n\n\nAbstract\nSmall-gain theory i
s known to be very useful in studying stability of\ninterconnected systems
. This theory is well-developed for very large\nclasses of essentially non
linear systems. This theory presumes that each\nsubsystem of an interconne
ction satisfies certain stability properties.\nHowever\, if some subsystem
s are not stable\, then small-gain conditions\ncannot be applied and we ca
nnot conclude about stability of the whole\nsystem. Only a few extensions
of the small-gain theory exist\, where\nsubsystems allowed to be not stabl
e. More general approaches should be\ndeveloped. In this presentation we d
emonstrate a new approach in this\ndirection\, which is based on positivit
y properties with respect to a\nspecial cone. With this approach we derive
sufficient stability\nconditions for a feedback connection of two subsyst
ems\, where one of\nthem can be not stable. In case both subsystems are st
able\, the\nsmall-gain approach can be applied as well. Hence a comparison
with\nsmall-gain condition is possible and is provided here. So far our\n
results are also restricted to a rather narrow class of systems\, however\
nextensions and developments to more general systems seem to be\nrealistic
\, which we discuss briefly at the end.\n\nBiography:\nSergey Dashk
ovskiy received the M.Sc. degree in applied mathematics in\n1996 from the
Lomonossov University of Moscow and Ph.D. degree in\nMathematics in 2002 f
rom the University of Jena. He has got his\nhabilitation (venia legendi) i
n Mathematics in 2009 from the university\nBremen.\nHe held positions at t
he Arizona State University\, the University of\nBayreuth and the Universi
ty of Applied Scienses Erfurt.\nSince 2016 he is professor and head of the
research group Dynamics and\nControl at the Institute for Mathematics\, U
niversity of Würzburg.\nHis research interests are in stability theory of
dynamical systems and\nnetworks.\nHe is editorial board member of several
journals related to this\nresearch area\, in particular\, of IEEE Transac
tions on Automatic Control\nand Nonlinear Analysis: Hybrid Systems.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Masashi Wakaiki (Kobe University\, Japan)
DTSTART:20230809T150000Z
DTEND:20230809T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/24
DESCRIPTION:Title: Semi-uniform ISS and iISS of infinite-dimensional systems\n
by Masashi Wakaiki (Kobe University\, Japan) as part of Input-to-State Sta
bility and its Applications\n\n\nAbstract\nIf an infinite-dimensional syst
em is strongly stable but not exponentially stable\, a rate of decay is no
t expected to be uniform for all solutions. Nevertheless\, one may establi
sh a uniform estimate on decay rates for all classical solutions\, which l
eads to the concept of semi-uniform stability. Specifically\, if all class
ical solutions decay at a polynomial rate\, the system is called polynomia
lly stable. This presentation aims to introduce the notions of semi-unifor
m ISS/iISS and its subclass\, polynomial ISS/iISS\, for infinite-dimension
al systems. I characterize semi-uniform ISS by attractivity properties and
discuss polynomial ISS of linear systems and polynomially iISS of bilinea
r systems.\n\nBiography: \nMasashi Wakaiki received the B.S. degree
in Engineering and the M.S. and Ph.D. degrees in Informatics from Kyoto U
niversity\, Kyoto\, Japan\, in 2010\, 2012\, and 2014\, respectively. He w
as a visiting scholar at the University of California\, Santa Barbara from
2014 to 2016. He was an Assistant Professor in the Department of Electric
al and Electronic Engineering\, Chiba University from 2016 to 2017. He was
a Lecturer in the Graduate School of System Informatics\, Kobe University
from 2017 to 2020\, where he is currently an Associate Professor. His res
earch interests include infinite-dimensional systems and networked control
systems.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Angeli (Imperial College London\, UK)
DTSTART:20230712T150000Z
DTEND:20230712T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/25
DESCRIPTION:Title: Input-to-State Stability for Complex Dynamics\nby David Ang
eli (Imperial College London\, UK) as part of Input-to-State Stability and
its Applications\n\n\nAbstract\nTraditional ISS is formulated for systems
globally defined on Euclidean space with a single equilibrium correspondi
ng to the unperturbed system (0 input disturbance). This limits its applic
ability to many other domains\, where multiple equilibria exists\, or more
exotic attractors (such as periodic solutions) or even multiple invariant
sets of different nature.\nIn this talk we provide an extension of the de
finitions and main results of ISS to this more general set-up\, arguing th
at a very natural extension of all the concepts is possible\, including as
ymptotic gain formulations and Lyapunov characterizations.\n\nBiography
: \nDavid Angeli received the B.S. degree in Computer Science Engineer
ing and the Ph.D. degree in Control Theory from University of Florence\, F
lorence\, Italy\, in 1996 and 2000\, respectively.\nSince 2000\, he was wi
th the Department of Systems and Computer Science\, University of Florence
\, as an Assistant Professor\, and an Associate Professor\, in 2005. In 20
07\, he was a Visiting Professor with I.N.R.I.A de Rocquencourt\, Paris\,
France\, and he joined as a Senior Lecturer the Department of Electrical a
nd Electronic Engineering\, Imperial College London\, London\, U.K.\, in 2
008\, where he is currently a Professor in Nonlinear Network Dynamics and
the Director of the MSc in Control and Optimisation. He has authored more
than 100 journal papers in the areas of stability of nonlinear systems\, c
ontrol of constrained systems (MPC)\, chemical reaction networks theory\,
and smart grids.\nProf Angeli is a Fellow of IEEE (2015) and of the Instit
ute of Engineering and Technology (IET)\, since 2018. He has served as an
Associate Editor for IEEE Transactions in Automatic Control and Automatica
.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Emilia Fridman (Tel Aviv University\, Israel)
DTSTART:20230726T150000Z
DTEND:20230726T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/26
DESCRIPTION:Title: Extremum seeking via a time-delay approach to averaging\nby
Emilia Fridman (Tel Aviv University\, Israel) as part of Input-to-State S
tability and its Applications\n\n\nAbstract\nExtremum Seeking (ES) is a po
werful real-time optimization method without requesting a knowledge of sys
tem model. A majority of ES algorithms employ highly oscillating dithers\,
where the stability analysis is based on the averaging theory. However\,
the existing results on averaging are qualitative: the original system is
stable for small enough values of the parameter if the averaged system is
stable. By using these results it is difficult to find an efficient bound
on the dither frequency that preserves the stability of the original syste
m.\n\n \n\nIn this talk I will present a new constructive time-delay appro
ach to averaging and apply it to ES.\n\nGradient-based ES of quadratic sta
tic maps via the classical and bounded ES algorithms will be considered. T
he practical stability analysis will be based on the transformation of the
ES system to a time-delay one\, where the delay is defined by the dither
frequency. The results will be extended to sampled-data and delayed implem
entations.\n\nThe time-delay approach leads to quantitative bounds on the
ES parameters for the ''grey box" models and explicit qualitative bounds f
or the ''black box" models making ES control reliable.\n\nThese are joint
results with my recent post-docs Yang Zhu (Zhejiang University)\, Jin Zhan
g (Shanghai University) and Xuefei Yang (Harbin Institute of Technology).\
n\nBiography:\nEmilia Fridman received the M.Sc and Ph.D in mathema
tics in Russia. Since 1993 she has been at Tel Aviv University\, where she
is currently Professor in the Department of Electrical Engineering - Syst
ems. She has held numerous visiting positions in Europe\, China and Austra
lia. Her research interests include time-delay systems\, networked control
systems\, distributed parameter systems\, robust control and extremum see
king. She has published more than 200 journal articles and 2 monographs.\n
\nIn 2021 she was recipient of IFAC Delay Systems Life Time Achievement Aw
ard and of Kadar Award for outstanding research in Tel Aviv University. In
2023 her monograph\n\n``Introduction to Time-Delay Systems: Analysis and
Control" (Birkhauser\, 2014) was the winner of IFAC Harold Chestnut Contro
l Engineering Textbook Prize.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Antoine Chaillet (L2S Paris-Saclay\, France)
DTSTART:20230719T150000Z
DTEND:20230719T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/27
DESCRIPTION:Title: ISS for delay systems: an overview and some open questions\
nby Antoine Chaillet (L2S Paris-Saclay\, France) as part of Input-to-State
Stability and its Applications\n\n\nAbstract\nThis talk provides an overv
iew of the input-to-state stability (ISS) framework for nonlinear time-del
ay systems. It aims at underlying the key differences existing with respec
t to both the finite-dimensional theory and the general infinite-dimension
al setting. This overview covers fundamental properties of time-delay syst
ems (including forward completeness and bounded reachability)\, input-free
stability properties (including asymptotic and exponential stability)\, a
nd ISS-related notions (including integral ISS). All these properties will
be discussed at the light of both solutions-based and Lyapunov-based char
acterizations. It will insist on some open questions that remain in the fi
eld to hopefully foster some discussion. This work is mostly based on a co
llaboration with I. Karafyllis\, P. Pepe and Y. Wang\, and particularly on
our recent survey paper "The ISS framework for time-delay systems: a surv
ey" written at the occasion of E.D. Sontag's 70th birthday.\n\nBiograph
y: \nAntoine Chaillet was born in Douai\, France\, in 1979. He receive
d his B.Sc. degree from ESIEE Amiens\, France\, and his M.Sc. degree in Co
ntrol Engineering from Univ. Paris Sud 11. In 2006\, he received his Ph.D.
degree in Control Theory from Univ. Paris Sud. In 2006–2007\, he served
as a post-doc fellow at Centro di Ricerca Piaggio\, Pisa\, Italy. From 20
07 to 2016\, he served as an associate professor at L2S-Univ. Paris Sud-Su
pélec. He is now full professor at CentraleSupélec and former junior mem
ber of Institut Universitaire de France. His research interests include st
ability analysis and stabilization of nonlinear systems\, time-delay syste
ms\, and control theory for neuroscience applications.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrii Mironchenko (University of Passau\, Germany)
DTSTART:20230802T150000Z
DTEND:20230802T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/28
DESCRIPTION:Title: Robust forward completeness: a bridge between well-posedness an
d stability.\nby Andrii Mironchenko (University of Passau\, Germany) a
s part of Input-to-State Stability and its Applications\n\n\nAbstract\nWel
l-posedness theory studies the existence and uniqueness of solutions of dy
namical and control systems\, but it does not tell us much about the bound
s of solutions. \nIn contrast to that\, the stability theory investigates
the global in time bounds for trajectories and families of trajectories.\n
\nWe know a lot about well-posedness and stability. But what do we know ab
out the terrain between these areas? In this talk\, I invite you to go wit
h me to these rather unexplored lands\, and summarize what we know about 2
related concepts: robust forward completeness (RFC) and boundedness of re
achability sets (BRS).\n\nRFC/BRS are important in many contexts:\n\n1. Th
ey were instrumental for the derivation of converse Lyapunov theorems for
global asymptotic stability in ODE setting. \n\n2. Uniform global asymptot
ic stability for infinite-dimensional systems has been characterized in te
rms of uniform weak attractivity\, local stability\, and RFC property. \n\
n3. Input-to-state stability (ISS) is equivalent to a combination of the u
niform limit property\, local stability\, and boundedness of reachability
sets (so-called ISS superposition theorem). \n\n4. These characterizations
\, in turn\, paved the way for the development of non-coercive Lyapunov me
thods\, where again BRS/RFC play an important role.\n\n5. Characterization
of global asymptotic stability for retarded systems is heavily dependent
on whether the systems are RFC. \n\n6. BRS/RFC help significantly to study
regularity of the flow of nonlinear infinite-dimensional control systems.
\n\nAnd now more formally:\n\nA control system is called forward complete
if for any initial condition $x$\, and any input $u$\, the corresponding t
rajectory $\\phi(\\cdot\,x\,u)$ is well-defined on the whole nonnegative t
ime axis. If additionally\, for any magnitude $R>0$ and any time $\\tau>0$
\n\\[\n\\sup_{\\|x\\| \\leq R\,\\ u\\in D\,\\ t\\in[0\,\\tau]} \\|\\phi(t\
,x\,u)\\| <+\\infty\,\n\\] \nwhere $D$ is the space of admissible inputs\,
then a control system is said to be robustly forward complete (RFC).\n\nW
e start by recalling the well-known result that forward completeness is eq
uivalent to RFC for ODE systems with Lischitz right-hand side. We demonstr
ate by means of an example\, that RFC is a stronger notion for infinite-di
mensional systems in Hilbert spaces with Lipschitz continuous rhs. \n\nWe
show that the robust forward completeness for distributed parameter system
s is equivalent to the existence of a corresponding Lyapunov function that
increases at most exponentially along the trajectories.\n\nWe demonstrate
several results showing importance of RFC and BRS concepts. \nFinally\, w
e state several open problems in this area.\n\nBiography:\nAndrii M
ironchenko was born in 1986 in Odesa\, Ukraine. He received the M.Sc. deg
ree in applied mathematics from the Odesa I.I. Mechnikov National Universi
ty\, Odesa\, Ukraine\, in 2008\, the Ph.D. degree in mathematics from the
University of Bremen\, Bremen\, Germany in 2012\, and the habilitation de
gree from the University of Passau\, Germany\, in 2023. He has held a rese
arch position with the University of Würzburg\, Würzburg\, Germany\, and
was a Postdoctoral Fellow of Japan Society for Promotion of Science (JSPS
) with the Kyushu Institute of Technology\, Fukuoka Prefecture\, Japan (20
13–2014). Since 2014\, he is with the Faculty of Mathematics and Compute
r Science\, University of Passau\, Passau\, Germany.\n\nDr. Mironchenko is
the author of the monograph „Input-to-State Stability“ (Springer\, 20
23) and (co)author of more than 60 peer-reviewed papers in journals and co
nference proceedings in control theory and applied mathematics. \nA. Miron
chenko is a co-founder and co-organizer of the Workshop series “Stabilit
y and Control of Infinite-Dimensional Systems” (SCINDIS). He is a Senior
Member of IEEE.\n\nHis research interests include stability theory\, nonl
inear systems theory\, distributed parameter systems\, hybrid systems\, an
d applications of control theory to biological systems and distributed con
trol.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Iasson Karafyllis (National Technical University of Athens)
DTSTART:20231018T150000Z
DTEND:20231018T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/29
DESCRIPTION:Title: Let’s Use Delays in Adaptive Control!\nby Iasson Karafyll
is (National Technical University of Athens) as part of Input-to-State Sta
bility and its Applications\n\n\nAbstract\nThis talk shows the first step
towards the resolution of several decades-old challenges in disturbance-ro
bust adaptive control. For a scalar\, delay-free\, linear system with an u
nknown parameter for which no a priori bound is given\, with a disturbance
that is of unlimited magnitude and possibly persistent (not square integr
able)\, and without a persistency of excitation necessarily verified by th
e state\, the problem of (practical) Input-to-Output Stability (IOS) asymp
totic gain assignment relative to the disturbance is studied. A solution t
o these heretofore unsolved feedback design problems is provided with the
aid of infinite-dimensional nonlinear feedback employing distributed delay
of the state and input itself. Specifically\, in addition to (0) global b
oundedness of the infinite-dimensional state of the closed-loop system whe
n the disturbance is present\, the following features are also established
: (1) practical IOS with assignable asymptotic gain from the disturbance t
o the plant state\; (2) assignable exponential convergence rate\; and (3)
assignable radius of the residual set. The accompanying identifier in the
proposed adaptive control scheme guarantees (4) boundedness of the paramet
er estimate even when disturbances are present\; (5) an ultimate estimatio
n error which is proportional to the magnitude of the disturbance with ass
ignable gain when there exists sufficient excitation of the state\; and (6
) exact parameter estimation in finite-time when the disturbance is absent
and there is sufficient excitation. Among the obtained results\, one reve
als a tradeoff between “learning capacity” and “disturbance robustne
ss:” the less sensitive the identifier is to the disturbance\, the less
likely it is to learn the parameter. This is a joint work with Miroslav Kr
stic and Alexandros Aslanidis. \n\nBiography: \nIasson Karafyll
is is a Professor of Mathematics in the Department of Mathematics of the N
ational Technical University of Athens. He is a coauthor of three books an
d he has written more than 100 journal papers. His research interests lie
in the stability theory and feedback stabilization theory of deterministic
control systems as well as in the connection of Mathematical Control Theo
ry with other areas of mathematics.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Felix Schwenninger (University of Twente\, Netherlands)
DTSTART:20231108T160000Z
DTEND:20231108T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/30
DESCRIPTION:Title: BIBO stability and ISS for infinite-dimensional systems\nby
Felix Schwenninger (University of Twente\, Netherlands) as part of Input-
to-State Stability and its Applications\n\n\nAbstract\nIn this talk we rev
isit Bounded-input-bounded-output (BIBO) stability for infinite-dimensiona
l systems. We discuss subtleties arising even in the linear case and its r
elations to ISS. The focus is on phenomena arising from boundary control a
nd observation.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jun Zheng (Southwest Jiaotong University\, Chengdu\, PR China)
DTSTART:20231025T150000Z
DTEND:20231025T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/31
DESCRIPTION:Title: ISS for the Burgers’ Equation with Dirichlet Boundary Disturb
ances and the Generalized Lyapunov Method\nby Jun Zheng (Southwest Jia
otong University\, Chengdu\, PR China) as part of Input-to-State Stability
and its Applications\n\n\nAbstract\nThe input-to-state stability (ISS) th
eory of partial differential equations (PDEs) has been developed for more
than one decade. During this period\, a few methods have been proposed for
establishing the ISS for PDEs subjected to distributed in-domain disturba
nces and various types of boundary disturbances. In particular\, the Lyapu
nov method has proven to be well-suited to PDEs with solely in-domain dist
urbances or boundary disturbances of Robin and Neumann types. However\, ap
plying the Lyapunov arguments the ISS analysis of PDEs with Dirichlet boun
dary disturbances meets a significant challenge.\n\nIn this presentation\,
we will first illustrate how to construct Lyapunov-like functionals to ac
hieve the ISS in different norms for the Burgers’ equation with Dirichle
t boundary disturbances. Unlike classical Lyapunov functionals\, which are
typically required to be positive definite\, these constructed Lyapunov-l
ike functionals can be positive semidefinite. Furthermore\, such functiona
ls are allowed to be depend on the boundary disturbances. As a result\, th
is kind of construction provides a wider range of choices for the ISS-Lyap
unov candidates and offers greater flexibility in applications.\n\nInspire
d by studying the ISS for the Burgers’ equation\, we will then show how
to extend the proposed approach to general infinite-dimensional systems. I
n particular\, we will introduce a new notion called the generalized ISS-L
yapunov functional (GISS-LF) by using positive semidefinite and disturbanc
e-dependent functionals. We will also present a generalized ISS-Lyapunov t
heorem\, indicating that the existence of a GISS-LF implies the ISS of the
considered system. Consequently\, the proposed approach can be seen as a
generalized Lyapunov method\, providing a new perspective for the ISS anal
ysis of infinite dimensional systems including PDEs with Dirichlet boundar
y disturbances. \n\nThis is a joint work with Prof. Guchuan Zhu from Polyt
echnique Montreal.\n\nBiography: \nJun Zheng received the Ph.D. deg
ree in mathematics from Lanzhou University\, Lanzhou\, China\, in 2013. He
joined Southwest Jiaotong University\, Chengdu\, China\, in 2013\, where
he is currently an associate professor at the School of Mathematics. He ha
s published more than 40 papers by peer-reviewed journals in the fields of
control and mathematics. His current research interests include control o
f distributed parameter systems\, nonlinear and robust control\, free boun
dary problems\, and regularity theory of PDEs.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nicolás Espitia (University of Lille - CNRS - CRIStAL laboratory\
, France)
DTSTART:20231122T160000Z
DTEND:20231122T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/32
DESCRIPTION:Title: Event-triggered boundary control of an unstable reaction diffus
ion PDE with input delay\nby Nicolás Espitia (University of Lille - C
NRS - CRIStAL laboratory\, France) as part of Input-to-State Stability and
its Applications\n\n\nAbstract\nEvent-triggered control has gained signif
icant attention within the control community and has already reached a cer
tain level of maturity within the framework of finite-dimensional networke
d control systems. However\, when it comes to infinite-dimensional systems
\, specifically partial differential equations (PDEs)\, this area remains
in its early stages. Event-triggered control for PDEs presents a multitude
of challenging issues\, including those theoretical ones related to well-
posedness\, the occurrence of the Zeno phenomenon\, and conservatism\, amo
ng others. The emergence of these challenges depends on various factors\,
such as the nature of the PDE (e.g.\, whether hyperbolic or parabolic)\, t
he way for sensing and actuation (in-domain or boundary)\, the design of t
he control methodology employed\, and the intended applications while mode
ling by a PDE setting.\n\nThis presentation will focus on recent advanceme
nts in event-triggered boundary control applied to a specific class of 1-d
imensional reaction-diffusion PDE with delayed boundary input. The discuss
ion will start by providing some fundamental elements of event-triggered c
ontrol and illustrative examples where event-triggered control can play a
fundamental role\, particularly in PDE control\, as this strategy can repr
esent a more realistic and practical means of actuating PDE systems.\nSubs
equently\, this talk will introduce an event-triggered boundary control st
rategy of reaction -diffusion PDEs for the delay-free case. This result is
crucial in preparing the basis for the extension to cases involving input
delays. Our methodology builds on well-established and powerful control d
esign techniques for PDEs\, such as the backstepping approach\, as well as
insights from Input-to-State Stability (ISS) results for PDEs and small-g
ain arguments. The presentation will highlight the employed event-triggeri
ng policy (using suitable spatial norms)\, the stability results\, and how
we can avoid the Zeno phenomenon.\nThis work is mostly based on a recent
collaboration with Miroslav Krstic and Florent Koudohode.\n\nBiography:
\nNicolas Espitia is a researcher at the CNRS (The National Center fo
r Scientific Research) since 2019 and develops his research activities wit
hin the CRIStAl laboratory (Research Center in Computer Science\, Signal a
nd Automatic Control of Lille) of the University of Lille\, France. \nHe r
eceived in 2017 his Ph.D. in Control Systems from the GIPSA-Lab\, Univers
ity of Grenoble\, France. From 2017 to 2019\, he was a postdoctoral resear
cher in Inria Lille Nord-Europe\, France. His research interests include e
vent-triggered control and finite-/fixed-/prescribed-time stabilization of
infinite-dimensional systems.\n\nReferences: \n\n-N. Espitia\; I.
Karafyllis\; M. Krstic "Event-triggered boundary control of constant-para
meter reaction-diffusion PDEs: A small-gain approach"\, Automatica\, Vol.
128\, 2021 (Doi: https://doi.org/10.1016/j.automatica.2021.109562\; HAL: h
ttps://hal.science/hal-03178456)\n\n-F. Koudohode\; N Espitia\; M. Krstic\
, "Event-triggered boundary control of an unstable reaction diffusion PDE
with input delay"\, under review in Systems & Control Letters (preprint av
ialable at HAL: https://hal.science/hal-04304378 ).\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Maurice Heemels (Eindhoven University of Technology\, Netherlands)
DTSTART:20231129T160000Z
DTEND:20231129T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/33
DESCRIPTION:Title: Projected Dynamics in Control\nby Maurice Heemels (Eindhove
n University of Technology\, Netherlands) as part of Input-to-State Stabil
ity and its Applications\n\n\nAbstract\nProjected Dynamical Systems (PDSs)
are a class of discontinuous and constrained dynamical systems in which p
rojection of dynamics is used to keep the state of the system in a given c
onstraint set. In this talk we will focus on the opportunities that PDS ma
y offer for high-performance control purposes. In particular\, we will con
sider the utilization of projection operators in control systems to overco
me fundamental performance limitations related to linear time-invariant (L
TI) control. As an exemplary controller\, we will discuss the so-called H
ybrid Integrator-Gain System (HIGS)\, being a projected integrator designe
d to avoid the limitations of linear integrators. The main design philosop
hy behind HIGS is built on keeping the sign of its input and output equal\
, thereby inducing less phase lag than a linear integrator\, which leads t
o direct performance benefits. The study of HIGS calls for an extension of
classical PDS (called “extended PDS”)\, as only partial projection of
the closed-loop states is allowed\; we can only change the controller sta
tes by projection\, not the plant states. This novel use of projection ope
rators can enforce desirable input-output (i/o) properties of the controll
er dynamics\, which were not present in the original (unprojected) dynamic
s. In fact\, we will show\, for instance\, how next to sign-equivalence p
roperties of inputs and outputs\, also passivity and general (qsr-)dissipa
tivity properties can be induced by projection on sector-like i/o constrai
nt sets. For the class of HIGS-controlled systems (and their formalization
s in terms of ePDSs)\, we discuss existence and forward completeness of so
lutions\, their discretizations and sampled-data implementations\, and (in
put-to-state and incremental) stability properties and illustrate them by
various examples and experiments. \n\nBiography: \nMaurice Heemels
received M.Sc. (mathematics) and Ph.D. (control theory) degrees (summa cu
m laude) from the Eindhoven University of Technology (TU/e) in 1995 and 19
99\, respectively. From 2000 to 2004\, he was with the Electrical Engineer
ing Department\, TU/e\, as an assistant professor\, and from 2004 to 2006
with the Embedded Systems Institute (TNO-ESI) as a research fellow. Since
2006\, he has been with the Department of Mechanical Engineering\, TU/e\,
where he is currently a Full Professor and vice-dean. Maurice held visitin
g professor positions at Swiss Federal Institute of Technology (ETH)\, Sw
itzerland (2001)\, University of California at Santa Barbara (2008) and Un
iversity of Lorraine\, France (2020). His current research includes hybrid
and cyber-physical systems\, networked and event-triggered control system
s and model predictive control. Dr. Heemels served/s on the editorial boar
ds of Automatica\, Nonlinear Analysis: Hybrid Systems\, Annual Reviews in
Control\, and IEEE Transactions on Automatic Control. He was a recipient
of a personal VICI grant awarded by NWO (Dutch Research Council) and an ER
C Advanced Grant (European Research Council). He is a Fellow of the IEEE a
nd IFAC. He was currently chair of the IFAC Technical Committee on Networ
ked Systems (2017-2023). He was the recipient of the 2019 IEEE L-CSS Outst
anding Paper Award and the 2020 Automatica Paper Prize Award. He was elect
ed for the IEEE-CSS Board of Governors (2021-2023). He is the Editor-in-C
hief of the IFAC journal Nonlinear Analysis: Hybrid Systems as of 2023.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Delphine Bresch-Pietri (MINES ParisTech\, France)
DTSTART:20231206T160000Z
DTEND:20231206T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/34
DESCRIPTION:Title: Input-to-State Stability and converse Lyapunov Theorem for Line
ar Difference Equations and Hyperbolic Partial Differential Equations\
nby Delphine Bresch-Pietri (MINES ParisTech\, France) as part of Input-to-
State Stability and its Applications\n\n\nAbstract\nIn this talk\, we will
focus on a specific type of time-delay systems\, namely\, linear differen
ce equations\, which are seldom studied in the literature. We will review
their strong connection with systems of Linear Hyperbolic Partial Differen
tial Equations and the corresponding control challenges. We will present s
ome contexts of hyperbolic PDEs in which stabilizing control laws could be
designed via the reformulation of the dynamics by means of a difference e
quation. We will also present how this reformulation could be used to expr
ess a converse Input-to-State Stability Lyapunov theorem for systems of hy
perbolic PDEs. This talk is inspired from recent works with Jean Auriol (C
NRS\, L2S).\n\nBiography: \nDelphine Bresch-Pietri is an Associate
Professor at Mines Paris - PSL\, at the Centre d'Automatique et Systèmes.
Her research areas include the theory and applications of time-delay syst
ems\, boundary control of Partial Differential Equations\, and optimizatio
n of time-delay systems. She is the co-author of a control engineering boo
k titled "Stabilité et Stabilisation" and holds several patents in the fi
eld of engine control. She has been an Associate Editor at Systems and Con
trol Letters since 2020 and at IEEE Transactions on Automatic Control sinc
e 2022.\n\nReferences: \n\n-Jean Auriol\, Delphine Bresch-Pietri. O
n Input-to-State Stability of Linear Difference Equations and\nIts Charact
erization with a Lyapunov Functional. IFAC World Congress 2023\nhttps://ha
l.science/hal-04051122/document\n\n-Auriol Jean\, Kong Sijia\, and Bresch-
Pietri Delphine. "Explicit prediction-based control for linear difference
equations with distributed delays." IEEE Control Systems Letters 6 (2022):
2864-2869.\nhttps://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=9786057\
n\n-Jean Auriol and Delphine Bresch Pietri. "Robust state-feedback stabili
zation of an underactuated network of interconnected n+ m hyperbolic PDE s
ystems." Automatica 136 (2022): 110040.\nhttps://www.sciencedirect.com/sci
ence/article/pii/S0005109821005689\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hernan Haimovich (Universidad Nacional de Rosario (UNR) and Consej
o Nacional de Investigaciones Científicas y Técnicas (CONICET)\, Argenti
na)
DTSTART:20231115T160000Z
DTEND:20231115T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/35
DESCRIPTION:Title: Forward Completeness is not robust for time-delay Systems: Intu
ition\, counterintuition and consequences\nby Hernan Haimovich (Univer
sidad Nacional de Rosario (UNR) and Consejo Nacional de Investigaciones Ci
entíficas y Técnicas (CONICET)\, Argentina) as part of Input-to-State St
ability and its Applications\n\n\nAbstract\nForward Completeness (FC) is t
he property indicating that solutions of a dynamical system are defined fo
r all future times. For ODEs that represent time-invariant dynamical syste
ms with inputs\, standard assumptions cause FC to be equivalent to Robust
FC (RFC)\, the latter meaning that solutions originating in bounded balls
and corresponding to inputs taking values in a compact set have uniform bo
unds over compact time intervals. The equivalence between FC and RFC cease
s to hold for infinite-dimensional systems\, but the validity of this equi
valence for the specific case of time-delay systems has until recently bee
n an open question. In this talk\, it will be shown that the FC and RFC of
usually encountered classes of time-delay systems are related to the FC o
f ODEs under different sets of admissible inputs: continuous inputs for FC
and measurable and locally essentially bounded inputs for RFC. The existe
nce of an FC time-delay system whose related ODE system is FC for continuo
us inputs but not for all bounded measurable inputs is shown with an inter
esting example from the realm of switched systems. This shows that FC is n
ot equivalent to RFC for time-delay systems. The perhaps counterintuitive
properties of the constructed example will be examined and the correspondi
ng consequences indicated. This talk ends by pointing to some problems tha
t may still remain open regarding the relationship between FC and RFC for
general time-delay systems. This is joint work with Prof. Jose Luis Mancil
la-Aguilar.\n\nBiography: \nHernan Haimovich graduated as an Electr
onics Engineer in 2001 at the Universidad Nacional de Rosario (UNR)\, Arge
ntina\, and finished his Ph.D. at The University of Newcastle\, Australia\
, in 2006. Dr. Haimovich currently holds a permanent Investigator position
from CONICET (the national research council of Argentina) and is a Profes
sor at the School of Electronics Engineering\, UNR. Dr. Haimovich is highl
y enthusiastic about applied mathematics in relation to control systems. H
is research interests include control theory for nonlinear\, switched\, ti
me-varying\, impulsive\, hybrid and/or discontinuous systems\, and related
applications.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sergiy Zhuk (IBM Research Europe\, Dublin\, Ireland)
DTSTART:20240110T160000Z
DTEND:20240110T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/36
DESCRIPTION:Title: Simulation-friendly detectability and ISS conditions for turbul
ent Navier-Stokes equations with unknown inputs\nby Sergiy Zhuk (IBM R
esearch Europe\, Dublin\, Ireland) as part of Input-to-State Stability and
its Applications\n\n\nAbstract\nWe will present simulation friendly detec
tability and ISS conditions for 2D Navier–Stokes Equation (NSE) with per
iodic boundary conditions\, and describe a generic class of ‘‘detectab
le’’ observation operators: it includes pointwise evaluation of NSE’
s solution at interpolation nodes\, and spatial average measurements. Our
analysis relies upon a novel one-parametric inequality relating $L^\\inft
y$ and $H^2$-norms of periodic vector-functions\, which for certain values
of the parameter reduces to Agmon and Brezis inequalities\, and S-procedu
re widely used in Lyapunov stability analysis.\n\nWe show that the soluti
on of NSE for an unknown initial condition for $\\vec a$ destabilizing unk
nown input belongs to $H^1$-ellipsoid which shrinks provided the uncertain
input ‘‘perturbs’’ the system less and less frequently as $t \\to
\\infty$\, or $L^2$-norm of this perturbation (in space) decays as $t \\t
o \\infty$\, a remarkable result for turbulent systems which are highly se
nsitive to small perturbations. \n\nFor ‘‘detectable’’ observatio
n operators we design a global infinite-dimensional observer for NSE with
uncertain possibly destabilizing inputs: in our numerical experiments we i
llustrate $H^1$-sensitivity of NSE to small perturbations of initial condi
tions\, yet the observer converges for known and uncertain inputs.\n\nB
iography: \nSergiy Zhuk is a Senior Research Scientist at IBM Research
Europe\, and he is a manager of the Quantum Computing group based in Dubl
in\, Ireland. Sergiy holds a Ph.D. in Applied Mathematics from Taras Shevc
henko National University of Kyiv\, Ukraine. In 2009 Sergiy was granted an
ERCIM/Marie Curie fellowship with Centrum Wiskunde Informatica (The Nethe
rlands) and INRIA Paris-Rocquencourt research center (France). Sergiy has
been a visiting scholar at Inria Paris research center and Mathematical in
stitute of Utrecht University. He joined IBM Research Europe in 2012. In 2
016–2019 he was an\nadjunct assistant professor at University College Du
blin. His research interests include state and parameter estimation for dy
namical systems\, inverse modeling\, Markov decision processes and (more r
ecently) quantum computing.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matthias Müller (Leibniz University Hannover\, Germany)
DTSTART:20240124T160000Z
DTEND:20240124T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/38
DESCRIPTION:Title: Incremental input/output-to-state stability and its application
in the analysis and design of optimization-based state estimators\nby
Matthias Müller (Leibniz University Hannover\, Germany) as part of Input
-to-State Stability and its Applications\n\n\nAbstract\nThe notion of incr
emental input/output-to-state stability (i-IOSS) was originally proposed b
y Sontag and Wang in 1997. It constitutes an extension of zero-detectabili
ty (which is implied by IOSS) to arbitrary trajectories and entails an asy
mptotic distinguishability property of states involving past input/output
data. Moreover\, it can be interpreted as robust generalization of standar
d (final state) observability for systems with unobservable\, asymptotical
ly decaying modes that are subject to process disturbances and measurement
noise\, and i-IOSS was even shown to be a necessary and sufficient proper
ty for the existence of robustly stable state estimators. In the first par
t of this talk\, we discuss how recently developed converse Lyapunov theor
ems for finite dimensional (discrete- and continuous-time) systems establi
sh equivalence of i-IOSS and existence of an exponential-decrease i-IOSS L
yapunov function. Furthermore\, we show how the strong relation to contrac
tion theory enables the application of straightforward tools to check expo
nential i-IOSS in practice using quadratically bounded i-IOSS Lyapunov fun
ctions.\n\nIn recent years\, i-IOSS has become the standard assumption of
nonlinear detectability in the context of optimization-based state estimat
ion for discrete-time systems\, in particular\, moving horizon estimation
(MHE). This technique is naturally applicable to nonlinear\, potentially c
onstrained systems and has applications in various fields\, such as chemic
al and process engineering\, biomedical engineering and systems medicine\,
robotics\, and power systems. In the second part of this talk\, we show h
ow strong robustness guarantees can be provided for MHE under i-IOSS when
the MHE cost function is chosen in accordance with the parameters of the i
-IOSS Lyapunov function. In particular\, this leads to practically relevan
t conditions for the design of nonlinear MHE schemes.\n\nBiography: \n Matthias A. Müller received a Diploma degree in Engineering Cyberneti
cs from the University of Stuttgart\, Germany\, an M.Sc. in Electrical and
Computer Engineering from the University of Illinois at Urbana-Champaign\
, US (both in 2009)\, and a Ph.D. from the University of Stuttgart in 2014
. Since 2019\, he is director of the Institute of Automatic Control and fu
ll professor at the Leibniz University Hannover\, Germany. His research in
terests include nonlinear control and estimation\, model predictive contro
l\, and data- and learning-based control\, with applications in different
fields including biomedical engineering and robotics. He has received vari
ous awards for his work\, including the 2015 European Systems & Control Ph
D Thesis Award\, the inaugural Brockett-Willems Outstanding Paper Award fo
r the best paper published in Systems & Control Letters in the period 2014
-2018\, an ERC starting grant in 2020\, the IEEE CSS George S. Axelby Outs
tanding Paper Award 2022\, and the Journal of Process Control Paper Award
2023. He serves as associate editor for Automatica\, editor of the Interna
tional Journal of Robust and Nonlinear Control\, and as a member of the Co
nference Editorial Board of the IEEE Control Systems Society.\n\nRelate
d references: \n\n-Sven Knüfer and Matthias A. Müller (2018).\n"Robu
st Global Exponential Stability for Moving Horizon Estimation".\nProc. IEE
E Conf. Decis. Control 2018\, p. 3477-3482.\nhttps://ieeexplore.ieee.org/d
ocument/8619617\n\n-Sven Knüfer and Matthias A. Müller (2020).\n"Time-Di
scounted Incremental Input/Output-to-State Stability".\nProc. IEEE Conf. D
ecis. Control 2020\, p. 5394-5400.\nhttps://ieeexplore.ieee.org/document/9
304034\n\n-Sven Knüfer and Matthias A. Müller (2023).\n"Nonlinear full i
nformation and moving horizon estimation: Robust global asymptotic stabili
ty".\nAutomatica 150\, p. 110603.\nhttps://www.sciencedirect.com/science/a
rticle/abs/pii/S0005109822004654?via%3Dihub\n\n-Julian D. Schiller and Mat
thias A. Müller (2023).\n"On an integral variant of incremental input/out
put-to-state stability and its use as a notion of nonlinear detectability"
.\nIEEE Contr. Syst. Lett. 7\, p. 2341-2346.\nhttps://ieeexplore.ieee.org/
document/10153397\n\n-Julian D. Schiller and Matthias A. Müller (2023).\n
"Robust stability of moving horizon estimation for continuous-time systems
".\narXiv:2305.06614.\nhttps://arxiv.org/abs/2305.06614\n\n-Julian D. Schi
ller\, Simon Muntwiler\, Johannes Köhler\, Melanie N. Zeilinger\, and Mat
thias A. Müller (2023).\n"A Lyapunov function for robust stability of mov
ing horizon estimation".\nIEEE Trans. Autom. Control 68(12)\, p. 7466-7481
.\nhttps://ieeexplore.ieee.org/document/10136787\n\n-Julian D. Schiller an
d Matthias A. Müller (2023).\n"Suboptimal nonlinear moving horizon estima
tion".\nIEEE Trans. Autom. Control 68(4)\, p. 2199-2214.\nhttps://ieeexplo
re.ieee.org/document/9772349\n\n-Julian D. Schiller and Matthias A. Mülle
r (2023).\n"Nonlinear moving horizon estimation for robust state and param
eter estimation."\narXiv:2312.13175.\nhttps://arxiv.org/abs/2312.13175\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sophie Tarbouriech (LAAS-CNRS\, Toulouse\, France)
DTSTART:20240221T160000Z
DTEND:20240221T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/39
DESCRIPTION:Title: Dynamic output feedback with adaptive saturation or dead-zone\nby Sophie Tarbouriech (LAAS-CNRS\, Toulouse\, France) as part of Input
-to-State Stability and its Applications\n\n\nAbstract\nIn this talk\, we
discuss the redesign of output feedback controllers (possible observer-lik
e) for linear systems based on adaptive saturation (stubborn) and dead-zon
e to improve noise reduction. With a stubborn redesign\, we improve the tr
ansient response of the closed loop to measurement outliers. Instead\, wit
h a dead-zone redesign\, we get a reduction in the sensitivity of the clos
ed loop to persistent disturbances such as measurement bias or Gaussian no
ise affecting the output. Hence\, for any given stabilizing linear dynamic
output feedback law designed for a multivariable linear plant\, we provid
e LMI-based stubborn/dead-zone redesign conditions that guarantee closed-l
oop exponential ISS. The feasibility of our LMI-based conditions is also p
roven. \n\nBiography: \nSophie Tarbouriech received the Ph.D. and H
DR degrees in Automatic Control from University Paul Sabatier\, Toulouse\,
France\, in 1991 and 1998\, respectively. She is full-time researcher (D
irecteur de Recherche CNRS) at LAAS-CNRS\, Toulouse. Her main research int
erests include analysis and control of linear and nonlinear systems with c
onstraints (limited information)\, hybrid dynamical systems. She is curren
tly Associate Editor for SIAM Journal on Control and Optimization and Seni
or Editor for IEEE Control Systems Letters. She is also Senior Editor and
Deputy Editor-in-Chief for Automatica. She is a member of International Fe
deration of Automatic Control and IEEE Technical Committees.\n\n Refere
nces: \n\n- S. Tarbouriech\, A. Alessandri\, D. Astolfi and L. Zaccari
an\, "LMI-Based Stubborn and Dead-Zone Redesign in Linear Dynamic Output F
eedback\," in IEEE Control Systems Letters\, vol. 7\, pp. 187-192\, 2023\,
doi: 10.1109/LCSYS.2022.3186842\, hal: hal-03726559.\n\n Slides: \
nhttp://mironchenko.com/__My_php_sources/ISS-Seminar-Talks/2024-02-21-Tarb
ouriech.pdf\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lucas Brivadis (L2S\, CNRS\, University Paris Saclay\, France)
DTSTART:20240214T160000Z
DTEND:20240214T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/40
DESCRIPTION:Title: Forward completeness and bounded reachability sets for time-del
ay systems: the role of the state space\nby Lucas Brivadis (L2S\, CNRS
\, University Paris Saclay\, France) as part of Input-to-State Stability a
nd its Applications\n\n\nAbstract\nA dynamical system is forward complete
(FC) if its solutions are well-defined for all future times. If moreover s
olutions initialized in bounded sets and corresponding to bounded inputs r
emain uniformly bounded over bounded time-intervals\, then it is said to h
ave the bounded reachability sets (BRS) property\, also called robust forw
ard completeness (RFC). BRS is a bridge between the pure well-posedness th
eory (that studies existence and uniqueness) and the stability theory (whi
ch is interested in establishing certain bounds for solutions). For exampl
e\, BRS is a crucial property to establish ISS superposition theorems. It
is known that under standard assumptions\, FC implies BRS for finite-dimen
sional systems\, while this fails for infinite-dimensional ones.\nIt was r
ecently shown by J.L. Mancilla-Aguilar and H. Haimovich that the implicati
on also fails in the case of time-delay systems with a finite number of de
lays. In this talk\, we aim to show that the implication FC => BRS for tim
e-delay systems actually heavily depends on the choice of the state space.
In particular\, we propose to consider the state space of essentially bou
nded functions (instead of the usual one of continuous functions). On this
new state space\, we prove that FC implies BRS\, which raises the questio
n of revisiting stability theory of time-delay systems in this state space
.\n\nBiography. Lucas Brivadis is a CNRS researcher at the Laborato
ry of Signals and Systems (L2S\, CentraleSupélec\, CNRS\, Université Par
is-Saclay). He defended his PhD in 2021 at LAGEPP\, Université Lyon 1. Fr
om 2021 to 2022\, he was a postdoctoral researcher at L2S. His research in
terests include stability properties of nonlinear delay systems\, observer
design for nonlinear or infinite dimensional systems\, and output feedbac
k stabilization.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fabian Wirth (University of Passau\, Germany)
DTSTART:20240131T160000Z
DTEND:20240131T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/41
DESCRIPTION:Title: The characterization of ISS for time-delay systems: Results and
Counterexamples\nby Fabian Wirth (University of Passau\, Germany) as
part of Input-to-State Stability and its Applications\n\n\nAbstract\nWe co
nsider a general class of time-delay systems with inputs. While\nthis defi
nes a class of infinite-dimensional systems\, it has been\nobserved for a
long time that the analytic properties of such systems\nare more benign th
an in the general infinite-dimensional case. To give\nan example\, it is a
classic result that for systems without input\nasymptotic stability of a
fixed point implies this property with a\nrate that is uniform in the stat
e space. As the state space is not\nlocally compact this is by no means as
self-evident as for ODEs.\n\nOn the other hand it is also known that the
infinite-dimensional\ncharater of time-delays systems results in propertie
s that are not\npossible for systems of ordinary differential equations. F
or instance\,\nin a recent paper\, Mancilla-Aguilar and Haimovich have sho
wn that\nforward completeness does not imply boundedness of finite-time\nr
eachability sets (the BRS property\, for short). Even more strikingly\,\nt
he example provided is even globally asymptotically stable and\nuniformly
globally attractive in the fixed point zero.\n\nAll this touches upon the
characterization of input-to-state stability\nfor time-delay systems in te
rms of other dynamic properties of the\nsystem. The properties that have t
urned out to be important are\n\nstability properties: (uniform) local sta
bility (LS/ULS)\,\nthe (uniform) limit property (LIM/ULIM)\, describing th
e long term behaviour of trajectories\,\n(uniform) asymptotic gains (AG/UA
G)\, describing asymptotic bounds on trajectories.\n\nFor finite-dimension
al control systems it has been shown by\nSontag and Wang that we have the
equivalence\n\nISS <=> LIM & LS <=> AG & LS\n\nIn contrast for a broad cla
ss of nonlinear infinite-dimensional\nsystems it has been shown that stron
ger requirements are needed\, namely\,\n\nISS <=> ULIM & ULS & BRS <=> UAG
& CEP & BRS\n\nAnd in the context of the general infinite-dimensional cla
ss this\ncharacterization cannot be relaxed. However\, delay systems are m
ore\nbenign so that it possible to relax the characterization to\n\nISS <=
> LIM & 0-ULS & BRS <=> AG & 0-ULS & BRS\n\nOn the other hand the example
of Mancilla-Aguilar and Haimovich may be\nextended to show that\, in the a
bsence of BRS\, LIM does not imply\nULIM. Also global asymptotic stability
does not imply uniform global\nattractivity. Thus the requirements on bou
nded reachability\nsets and uniformity properties of the stability require
ments cannot be\nremoved in the time-delay case.\n\njoint work with\n\nLuc
as Brivadis\, Université Paris-Saclay\, CNRS\, CentraleSupélec\, LSS\, F
rance\,\n\nAntoine Chaillet\, Université Paris-Saclay\, CNRS\, CentraleSu
pélec\, LSS\, France\,\n\nAndrii Mironchenko\, University of Klagenfurt\,
Austria and University of Passau\, Germany.\n\nBiography. \nFabian
Wirth received his PhD from the Institute of Dynamical Systems at\nthe Un
iversity of Bremen in 1995. He has since held positions in Bremen\,\nat th
e Centre Automatique et Systèmes of Ecole des Mines\, the\nHamilton Insti
tute at NUI Maynooth\, Ireland\, the University of Würzburg and IBM Resea
rch Ireland. \nHe now holds the chair for Dynamical Systems at the Univers
ity\nof Passau in Germany. His current interests include stability\ntheory
\, switched systems\, the joint spectral radius of matrix sets and large s
cale networks with \napplications to networked systems and distributed con
trol.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrii Mironchenko (University of Klagenfurt\, Austria)
DTSTART:20240117T160000Z
DTEND:20240117T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/42
DESCRIPTION:Title: Revisiting Lyapunov-Krasovskii methodology for robust stability
analysis of time-delay systems\nby Andrii Mironchenko (University of
Klagenfurt\, Austria) as part of Input-to-State Stability and its Applicat
ions\n\n\nAbstract\nLyapunov-Krasovskii functionals are a classical tool t
o study asymptotic stability and \ninput-to-state stability of time-delay
systems. \nHowever\, in the ISS context\, the requirements on the Lyapunov
-Krasovskii functionals \nare much stronger than those used for analysis o
f asymptotic stability. \n\nWhy? Can we fix it?\n\nIn this talk\, we show
a Lyapunov-Krasovskii direct theorem\nfor ISS of time-delay systems. This\
ntheorem is valid for systems with mild regularity of the right-\nhand sid
e and imposes fewer requirements on the Lyapunov-\nKrasovskii functional t
han the known results. Finally\, we derive\na stronger property than class
ical ISS.\nTo prove this result\, we introduce a new stability formalism\n
for delay systems with inputs and establish the \nISS superposition theore
m specifically tailored for time-delay systems.\n\nBiography. An
drii Mironchenko was born in 1986 in Odesa\, Ukraine. He received the Ph.
D. degree in mathematics from the University of Bremen\, Germany\, and the
habilitation degree from the University of Passau\, Germany. He was a Pos
tdoctoral Fellow of Japan Society for Promotion of Science (2013–2014).
Since 2023\, he is with the Department of Mathematics\, University of Kla
genfurt\, Austria.\n\nDr. Mironchenko is the author of the monograph „In
put-to-State Stability“ (Springer\, 2023) and of 70 journal and conferen
ce papers on control theory and applied mathematics. \nA. Mironchenko serv
es as an Associate Editor in Systems & Control Letters and is a co-founder
and co-organizer of the biennial Workshop series “Stability and Control
of Infinite-Dimensional Systems” (SCINDIS\, 2016 - now). He is a Senior
Member of IEEE.\nHe is a recipient of 2023 IEEE CSS George S. Axelby Outs
tanding Paper Award.\n\nHis research interests include stability theory\,
nonlinear systems theory\, distributed parameter systems\, hybrid systems\
, and applications of control theory to biological systems and distributed
control.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vincent Andrieu (LAGEPP\, University of Lyon\, France)
DTSTART:20240515T150000Z
DTEND:20240515T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/43
DESCRIPTION:Title: Adding an integral action to controlled PDE subject to input no
nlinearities\nby Vincent Andrieu (LAGEPP\, University of Lyon\, France
) as part of Input-to-State Stability and its Applications\n\n\nAbstract\n
To enhance the performance of a control law\, it is often recommended to i
ncorporate an integral action. \nDrawing inspiration from Seppo Pohjolaine
n's initial work\, we demonstrate how it is possible to design such contro
l laws within the context of partial differential equations employing an I
SS-Lyapunov approach. \nAdditionally\, we investigate scenarios where the
control is affected by nonlinearity\, such as saturation.\n\nBiography:
\nVincent Andrieu\, a Senior Researcher at CNRS\, earned his degree i
n applied mathematics from INSA de Rouen\, France\, in 2001. Following his
tenure at ONERA (French aerospace research company)\, he completed his Ph
.D. at Ecole des Mines de Paris in 2005. In 2006\, he conducted research a
t the Control and Power Group\, Dept. EEE\, Imperial College London. Joini
ng the CNRS-LAAS lab in Toulouse in 2008 as a CNRS-charge de recherche\, h
e transitioned to LAGEPP-CNRS\, Université Claude Bernard Lyon 1\, France
\, in 2010. During a sabbatical from 2014 to 2016\, he collaborated with t
he functional analysis group at Bergische Universitat Wuppertal in Germany
. Vincent's primary research focuses on the feedback stabilization of cont
rolled dynamical nonlinear systems and state estimation problems. He also
explores practical applications in aeronautics and chemical engineering. S
ince 2018\, he serves as an associate editor for the IEEE Transactions on
Automatic Control and holds the position of senior editor for System & Con
trol Letters.\n\nReferences: \n\n- A. Terrand-Jeanne\, V. Andrieu\,
V. Dos Santos Martins\, C.-Z. Xu\, Adding integral action for open-loop e
xponentially stable semigroups and application to boundary control of PDE
systems\, IEEE Transactions on Automatic Control\, Vol. 65\, Issue: 11\, N
ov. 2020. \nhttps://hal.archives-ouvertes.fr/hal-01971584/document\n\n- D.
Astolfi\, S. Marx\, V Andrieu\, C. Prieur\, Global exponential set-point
regulation for linear operator semigroups with input saturation 2022 IEEE
61st Conference on Decision and Control (CDC)\, 2022\nhttps://hal.science/
hal-04005700/document\n\n- L. Ma\, V. Andrieu\, D. Astolfi\, M. Bajodek\,
C.-Z. Xu and X. Lou\, Integral action feedback design for conservative abs
tract systems in the presence of input nonlinearities\, under review - IEE
E Transactions on Automatic Control.\nhttps://hal.science/hal-04577332\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pauline Bernard (Mines Paris\, France)
DTSTART:20240522T150000Z
DTEND:20240522T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/44
DESCRIPTION:Title: ISS-like properties in observer design with non-invertible chan
ge of coordinates\nby Pauline Bernard (Mines Paris\, France) as part o
f Input-to-State Stability and its Applications\n\n\nAbstract\nBy reviewin
g the field of observer design for nonlinear continuous-time systems\, we
show that most designs rely on a (left-invertible) change of coordinates t
hat brings the system dynamics into a normal form of potentially larger di
mension\, where an observer can be written. The goal of the seminar is to
discuss in what sense ISS properties of the observer can be recovered in t
he system coordinates\, depending on the properties of the left-inverse of
the transformation.\nIn particular\, the KKL paradigm consists in transfo
rming the system dynamics into a linear filter of the output\, which prese
nts all the nice ISS properties. The state of the original system is obtai
ned by implementing this filter from any initial condition and left-invert
ing the transformation\, if the system is backward-distinguishable. But we
show that this theory is still relevant when the latter assumption does n
ot hold\, namely when distinct solutions may generate the same output\, an
d thus be indistinguishable: the system state is then reconstructed modulo
its indistinguishable class. More precisely\, the KKL transformation is n
o longer injective and its “left-inverse” is allowed to be set-valued\
, yielding a set-valued KKL observer. We show that ISS-like properties can
still be ensured\, but in the Hausdorff sense\, with the observer converg
ing in a robust way to the backward-indistinguishable set of the system so
lution. We show that this paradigm also applies to hybrid systems with unk
nown jump times\, where the states before and after the jumps are typicall
y indistinguishable: ISS-like properties are then ensured\, but in terms o
f a distance to an appropriate set\, quantifying that the state and the es
timates are either close or one jump ahead/late from each other.\n\nBio
graphy: \nPauline Bernard graduated in Applied Mathematics from Mines
Paris in 2014 (formerly MINES ParisTech). She joined the Centre Automatiqu
e et Systèmes (CAS) of Mines Paris and obtained her Ph.D. in Mathematics
and Control from Université PSL in 2017. For her work on observer design
for nonlinear systems\, she obtained the European Ph.D. award on Control f
or Complex and Heterogeneous Systems 2018. As a post-doctoral scholar\, sh
e visited the Hybrid Systems Lab at the University California Santa Cruz\,
USA\, and the Center for Research on Complex Automated Systems at the Un
iversity of Bologna\, Italy. Since 2019\, she is associate professor at th
e Centre Automatique et Systèmes of Mines Paris - PSL\, France. Her resea
rch interests cover the observation and output regulation of nonlinear and
hybrid systems.\n\nReferences: \n\n- P. Bernard\, M. Maghenem\, Re
constructing indistinguishable solutions via a set-valued KKL observer\, A
utomatica\, Vol 166\, 2024\n\n- V. Alleaume\, P. Bernard\, KKL observer de
sign for non observable systems\, IFAC Symposium on Nonlinear Control Syst
ems\, 2023\n\n- P. Bernard\, V. Andrieu\, D. Astolfi\, Observer design for
continuous-time systems\, Annual Reviews in Control\, 2022\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tengfei Liu (Northeastern University\, China)
DTSTART:20240529T150000Z
DTEND:20240529T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/45
DESCRIPTION:Title: Singular Perturbation: When the Perturbation Parameter Becomes
a State-Dependent Function\nby Tengfei Liu (Northeastern University\,
China) as part of Input-to-State Stability and its Applications\n\n\nAbstr
act\nThis paper introduces a new class of singularly perturbed systems in
which the small\, but constant\, perturbation coefficient in standard sing
ular perturbation theory is replaced by a state-dependent function. This g
eneralization is aimed at broadening the applicability of singular perturb
ation theory in practice. For this class of singularly perturbed systems\,
it is assumed that the boundary-layer subsystem is globally asymptoticall
y stable (GAS) at the origin and the reduced subsystem is input-to-state s
table (ISS) with respect to the state of the boundary-layer subsystem. Und
er a mild monotonicity condition\, sufficient conditions on the perturbati
on functions are given under which the singularly perturbed system is GAS
at the origin. ISS and nonlinear small-gain techniques are exploited in th
e stability analysis. The efficacy of the proposed theoretical result is v
alidated via its applications to tackling integral control and feedback op
timization problems.\n\nBiography: Tengfei Liu received the B.E. de
gree in automation\, in 2005\, the M.E. degree in control theory and contr
ol engineering\, in 2007\, both from South China University of Technology\
, and the Ph.D. degree in engineering from RSISE\, the Australian National
University\, Canberra\, in 2011. From 2011 to 2013\, he was a Postdoc wit
h faculty fellowship at Polytechnic Institute of New York University. Sinc
e 2014\, he has been associated with the State Key Laboratory of Synthetic
al Automation for Process Industries at Northeastern University\, China\,
where he holds the position of full professor. His research interests incl
ude stability and control of interconnected nonlinear systems. He has serv
ed as Associate Editor for IEEE Transactions on Automatic Control\, System
s and Control Letters\, and Science China: Information Sciences. Dr. Liu i
s a senior member of IEEE.\n\nReferences:\n\n- T. Liu\, Z.P. Jiang\
, Singular Perturbation: When the Perturbation Parameter Becomes a State-D
ependent Function\, 12th IFAC Symposium on Nonlinear Control Systems\, 202
3.\n\n- T. Liu\, Z.P. Jiang\, Singular Perturbation: When the Perturbation
Parameter Becomes a State-Dependent Function\, arXiv:2406.00753 [math.OC]
\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Antoine Girard (L2S Paris-Saclay\, France)
DTSTART:20240612T150000Z
DTEND:20240612T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/46
DESCRIPTION:Title: Towards gain-optimal ISS controllers for finite state systems\nby Antoine Girard (L2S Paris-Saclay\, France) as part of Input-to-Stat
e Stability and its Applications\n\n\nAbstract\nInspired by the notion of
Input-to-State Stability (ISS)\, we introduce in this talk an optimal cont
rol problem for finite state dynamical systems [1]. We introduce a notion
of ISS for such systems and aim at synthesizing controllers with minimal I
SS-gain\, for a given order on gain functions (e.g. for the lexicographic
order). We then present an algorithm based on the synthesis framework of [
2] for computing ISS controllers. Optimality conditions for the synthesize
d controllers\, that can be checked a posteriori\, are provided. We then d
iscuss how the results presented in this paper can used for controlling no
nlinear continuous dynamical systems using finite state abstractions.\n\n<
b>References: \n\n[1] Apaza-Perez\, W. A.\, & Girard\, A. (2024). Synt
hesis of Input-to-State Attractivity Controllers for Transition Systems wi
th Disturbances. IEEE Transactions on Automatic Control. https://doi.org/1
0.1109/TAC.2024.3385068.\n\n[2] Girard\, A.\, & Eqtami\, A. (2021). Least-
violating symbolic controller synthesis for safety\, reachability and attr
activity specifications. Automatica\, 127\, 109543. https://doi.org/10.101
6/j.automatica.2021.109543.\n\nBiography: \nAntoine Girard is a Sen
ior Researcher at CNRS and a member of the Laboratory of Signals and Syste
ms. He received the Ph.D. degree from Grenoble Institute of Technology\, i
n 2004. From 2004 to 2006\, he held postdoctoral positions at University o
f Pennsylvania and Université Grenoble-Alpes. From 2006 to 2015\, he was
an Assistant/Associate Professor at the Université Grenoble-Alpes. His ma
in research interests deal with analysis and control of hybrid systems wit
h an emphasis on computational approaches\, formal methods and application
s to cyber-physical and autonomous systems. Antoine Girard is an IEEE Fell
ow. In 2015\, he was appointed as a junior member of the Institut Universi
taire de France (IUF). In 2016\, he was awarded an ERC Consolidator Grant.
He received the George S. Axelby Outstanding Paper Award from the IEEE Co
ntrol Systems Society in 2009\, the CNRS Bronze Medal in 2014\, and the Eu
ropean Control Award in 2018.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/46/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrea Bisoffi (Politecnico di Milano\, Italy)
DTSTART:20240703T150000Z
DTEND:20240703T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/47
DESCRIPTION:Title: Data-driven input-to-state stabilization\nby Andrea Bisoffi
(Politecnico di Milano\, Italy) as part of Input-to-State Stability and i
ts Applications\n\n\nAbstract\nDesigning control laws that make a generic
nonlinear system input-to-state stable with respect to exogenous inputs re
mains nontrivial even when a model of the nonlinear system is available. T
his becomes even less trivial if one does not have a model of the nonlinea
r system but relies only on noisy data from such a system\, where the nois
e leads to a set of possible models among which the actual system is not d
istinguishable. We have noted in previous works that input-affine nonlinea
r systems with polynomial dynamics lend themselves to the design of a cont
rol law to achieve asymptotic stabilization or robust invariance thanks to
sum-of-squares programs. In this talk\, we ask the question whether for t
his class of nonlinear systems it is possible to design a control law to a
chieve input-to-state stabilization of the closed-loop system and we provi
de a positive answer.\n\nBiography: \nAndrea Bisoffi is an assistan
t professor at Politecnico di Milano. He received the M.Sc. degree in Auto
matic Control Engineering from Politecnico di Milano and the Ph.D. degree
in Mechatronics from University of Trento. He was a post-doctoral research
er at KTH Royal Institute of Technology\, Sweden\, and a researcher at Uni
versity of Groningen\, The Netherlands. His research interests include hyb
rid and nonlinear control systems\, with applications to mechatronic syste
ms\, and data-driven control.\n\nReferences:\n\n- Hailong Chen\, An
drea Bisoffi\, Claudio De Persis. "Data-Driven Input-to-State Stabilizatio
n with Respect to Measurement Errors"\, 2023.\nAvailable at https://doi.or
g/10.1109/CDC49753.2023.10383880 and https://arxiv.org/abs/2309.09050\n\n-
Hailong Chen\, Andrea Bisoffi\, Claudio De Persis. "Data-driven input-to-
state stabilization"\, 2024.\nAvailable at https://arxiv.org/abs/2407.0604
4\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michael Malisoff (Louisiana State University\, USA)
DTSTART:20240605T150000Z
DTEND:20240605T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/48
DESCRIPTION:Title: Event-Triggered Control Using Interval Observers\nby Michae
l Malisoff (Louisiana State University\, USA) as part of Input-to-State St
ability and its Applications\n\n\nAbstract\nEvent-triggered control provid
es the foundation for significant current research\, owing to the ability
of\nevent-triggered control methods to take communication or other constra
ints into account by only changing values of feedback controls when a sign
ificant enough event calls for changing the control values. This calls for
finding formulas for feedback controls and for studying criteria to use t
o decide when to change the control values. This talk summarizes the speak
er's recent research on event-triggered control theory and applications in
marine robotics\, which is collaborative with Corina Barbalata\, Zhong-Pi
ng Jiang\, and Frederic Mazenc. The talk will be understandable to those f
amiliar with the basic theory of ordinary differential equations. No prere
quisite background in systems and control will be needed to understand and
appreciate this talk.\n\nBiography:\nMichael Malisoff is the Roy P
aul Daniels Professor #3 in the LSU College of Science. He earned his PhD
in Mathematics in 2000 from Rutgers University\, and joined the LSU Depart
ment of Mathematics faculty in 2001. His research is on systems and contro
l\, with an emphasis on engineering applications. His current research foc
uses on event-triggered control and reference governors\, with application
s to aerospace and marine robotic models and disease dynamics\, including
delay systems. He received two 3-year NSF Mathematical Sciences Priority A
rea grants\, and 9 Best Presentation awards in American Control Conference
sessions. He has served as Associate Editor for Automatica and IEEE Trans
actions on Automatic Control\, and is currently an associate editor of Eur
opean Journal of Control and of SIAM Journal on Control and Optimization.
\n\nReferences: \n\nAlyahia\, Safeyya\, Corina Barbalata\, Michael
Malisoff\, and Frédéric Mazenc. "Dynamic event-triggered control of line
ar continuous-time systems using a positive systems approach." Nonlinear A
nalysis: Hybrid Systems 54 (2024): 101508. DOI: https://doi.org/10.1016/j.
nahs.2024.101508\n\nMazenc\, Frederic\, Michael Malisoff\, and Corina Barb
alata. "Event-triggered control for continuous-time linear systems with a
delay in the input." Systems & Control Letters 159 (2022): 105075. DOI: ht
tps://doi.org/10.1016/j.sysconle.2021.105075\n\nYao\, Ningshi\, Michael Ma
lisoff\, and Fumin Zhang. "Contention-resolving model predictive control f
or coupled control systems with a shared resource." Automatica 122 (2020):
109219. DOI: https://doi.org/10.1016/j.automatica.2020.109219\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/48/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Abolfazl Lavaei (Newcastle University\, UK)
DTSTART:20240710T150000Z
DTEND:20240710T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/49
DESCRIPTION:Title: Formal Learning and Control of Large-Scale Cyber-Physical Syste
ms via ISS Properties\nby Abolfazl Lavaei (Newcastle University\, UK)
as part of Input-to-State Stability and its Applications\n\n\nAbstract\nIn
the past few years\, large-scale stochastic cyber-physical systems (CPS)
have received remarkable attentions as a beneficial modelling framework de
scribing a wide range of real-life safety-critical systems including autom
otive\, robotics\, transportation systems\, energy\, healthcare\, and crit
ical infrastructures. Formal verification and controller synthesis for thi
s type of complex systems to enforce high-level logic properties\, e.g.\,
those expressed as temporal logic formulae\, are inherently very challengi
ng mainly due to (i) large dimension of state/input sets\, (ii) stochastic
nature of dynamics\, (iii) tight interaction between physical and cyber c
omponents\, (iv) dealing with complex logic requirements\, and (v) lack of
closed-form mathematical models in many real-world applications. In this
talk\, I will discuss leveraging ISS properties to develop compositional (
data-driven) techniques that tackle the aforementioned difficulties and de
sign highly reliable CPS by bringing together interdisciplinary concepts f
rom formal methods in computer science\, control theory\, and data science
.\n\nBiography: \nAbolfazl Lavaei is an Assistant Professor in the
School of Computing at Newcastle University\, United Kingdom. Between Janu
ary 2021 and July 2022\, he was a Postdoctoral Associate in the Institute
for Dynamic Systems and Control at ETH Zurich\, working with Prof. Emilio
Frazzoli on “Trustworthy Safety-Critical AI for Autonomous Vehicles”.
He was also a Postdoctoral Researcher in the Department of Computer Scienc
e at LMU Munich\, between November 2019 and January 2021. He received the
Ph.D. degree in Electrical Engineering from the Technical University of Mu
nich (TUM)\, in 2019. His line of research mainly focuses on theoretical a
nd practical aspects of “Safe Verification\, Learning and Control of Lar
ge-Scale Stochastic Cyber-Physical Systems” with application to autonomo
us systems. He is the recipient of several international awards in the ac
knowledgment of his work including ADHS Best Repeatability Prize 2021\, HS
CC Best Demo/Poster Awards 2020 and 2022\, IFAC Young Author Award Finalis
t 2019\, and Best Graduate Student Award 2014 at University of Tehran.\n\n
References:\n\n[1] A. Lavaei and E. Frazzoli\, “Scalable Synthesi
s of Safety Barrier Certificates for Networks of Stochastic Switched Syste
ms"\, IEEE Transactions on Automatic Control\, 2024.\n\n[2] A. Lavaei and
E. Frazzoli\, “A Compositional Dissipativity Approach for Data-Driven Sa
fety Verification of Large-Scale Dynamical Systems"\, IEEE Transactions on
Automatic Control\, 2023.\n\n[3] A. Lavaei\, L. Di Lillo\, A. Censi\, and
E. Frazzoli\, “Formal Estimation of Collision Risks for Autonomous Vehi
cles: A Compositional Data-Driven Approach"\, IEEE Transactions on Control
of Network Systems\, 2022.\n\n[4] A. Nejati\, A. Lavaei\, et al.\, “For
mal Verification of Unknown Discrete- and Continuous-Time Systems: A Data-
Driven Approach"\, IEEE Transactions on Automatic Control\, 2023.\n\n[5] M
. Anand\, A. Lavaei\, and Majid Zamani\, "From Small-Gain Theory to Compos
itional Construction of Barrier Certificates for Large-Scale Stochastic Sy
stems"\, IEEE Transactions on Automatic Control\, 2022.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jean Auriol (L2S Paris-Saclay\, France)
DTSTART:20240717T150000Z
DTEND:20240717T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/50
DESCRIPTION:Title: Stabilization of systems of coupled hyperbolic PDEs and charact
erization of their ISS properties using Lyapunov functions\nby Jean Au
riol (L2S Paris-Saclay\, France) as part of Input-to-State Stability and i
ts Applications\n\n\nAbstract\nIn this talk\, we focus on the exponential
stabilization of systems of coupled hyperbolic PDEs and the characterizati
on of their ISS properties using Lyapunov functions. \nStarting from the t
utorial example of two coupled scalar equations\, we first show how the ba
ckstepping approach can be used to simplify the structure of the system to
design robust stabilizing controllers. We then characterize the closed-lo
op stability using an appropriate ISS Lyapunov function corresponding to t
he classical L2-norm of the system with exponential gains. We finally show
how such a function can help design advanced control strategies such as e
vent-triggered or gain-scheduling controllers. \n\nAlthough the backsteppi
ng approach can still be used to design stabilizing controllers for system
s of higher dimensions\, it may only sometimes be possible to explicitly o
btain the corresponding ISS Lyapunov function\, as most contributions in t
he literature require dissipative boundary conditions. To overcome this li
mitation\, we use the method of characteristics to rewrite the hyperbolic
system as Integral Delay Equations (IDEs)\, a class of difference equation
s with pointwise and distributed delayed terms. Grounding on recent works
on necessary conditions for the exponential stability of such systems\, we
propose a quadratic Lyapunov functional involving the derivative of the s
o-called delay Lyapunov matrix. We then prove that the ISS of the system i
s equivalent to the existence of an ISS Lyapunov functional that we can ex
plicitly design.\n\nBiography: \nJean Auriol is a Researcher (Cha
rgé de Recherches) at CNRS\, Université Paris-Saclay\, Centrale Supelec\
, Laboratoire des Signaux et Systèmes (L2S)\, Gif-sur-Yvette\, France. He
received his Ph.D degree from Ecole des Mines Paris\, PSL Research Univer
sity in 2018\, and obtained his Habilitation à Diriger des Recherches fro
m Université Paris-Saclay in 2024. His research interests include robust
control of hyperbolic systems\, neutral systems\, under-actuated networks
and interconnected systems. Past and current applications of interest incl
ude Oil & Gas and geothermal drilling\, and the analysis of neural fields.
\n\nReferences: \n\nAuriol\, J.\, & Bresch-Pietri\, D. (2023). On i
nput-to-state stability of linear difference equations and its characteriz
ation with a Lyapunov functional. IFAC-PapersOnLine\, 56(2)\, 929-934.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/50/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eduardo Sontag & Leilei Cui (Northeastern University (Boston) & Ma
ssachusetts Institute of Technology\, US)
DTSTART:20250402T150000Z
DTEND:20250402T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/52
DESCRIPTION:Title: ISS properties of gradient systems\nby Eduardo Sontag & Lei
lei Cui (Northeastern University (Boston) & Massachusetts Institute of Tec
hnology\, US) as part of Input-to-State Stability and its Applications\n\n
\nAbstract\nSolutions of optimization problems\, including policy optimiza
tion in reinforcement learning\, typically rely upon some variant of gradi
ent descent. There has been much recent work in the machine learning\, con
trol\, and optimization communities applying the Polyak-Łojasiewicz Inequ
ality (PŁI) to such problems in order to establish an exponential rate of
convergence (a.k.a. “linear convergence” in the local-iteration lang
uage of numerical analysis) of loss functions to their minima under the gr
adient flow. Often\, as is the case of policy iteration for the continuous
-time LQR problem\, this rate vanishes for large initial conditions\, resu
lting in a mixed globally linear / locally exponential behavior. This is i
n sharp contrast with the discrete-time LQR problem\, where there is globa
l exponential convergence. That gap between CT and DT behaviors motivates
the search for various generalized PŁI-like conditions\, and this talk wi
ll address that topic. Moreover\, these generalizations are key to underst
anding the transient and asymptotic effects of errors in the estimation of
the gradient\, errors which might arise from adversarial attacks\, wrong
evaluation by an oracle\, early stopping of a simulation\, inaccurate and
very approximate digital twins\, stochastic computations (algorithm "repro
ducibility")\, or learning by sampling from limited data. We will describe
an “input to state stability” (ISS) analysis of this issue. We will a
lso briefly discuss variations such as Newton-like and natural gradient fl
ows. (Joint work of the authors with A.C.B. de Oliveira and Z.P. Jiang).
\n\nBiographies:\nLeilei Cui received the M.Sc. degree in control s
cience and engineering from Shanghai Jiao Tong University\, Shanghai\, Chi
na\, in 2019\, and the Ph.D. degree in electrical engineering from New Yor
k University\, Brooklyn\, NY\, USA\, in 2024. He is now a postdoctoral ass
ociate at the Massachusetts Institute of Technology\, Cambridge\, MA\, USA
. His research interests include optimization\, optimal control\, reinforc
ement learning\, and adaptive dynamic programming. \n\nEduardo D. Sontag r
eceived his Licenciado in Mathematics at the University of Buenos Aires (1
972) and a Ph.D. in Mathematics (1977) under Rudolf E. Kalman at the Unive
rsity of Florida. From 1977 to 2017\, he was at Rutgers University\, where
he was a Distinguished Professor of Mathematics and a Member of the Gradu
ate Faculty of the Departments of Computer Science and of Electrical and C
omputer Engineering and the Cancer Institute of NJ. He directed the underg
raduate Biomathematics Interdisciplinary Major and the Center for Quantita
tive Biology\, and was Graduate Director at the Institute for Quantitative
Biomedicine. In January 2018\, Dr. Sontag became a University Distinguish
ed Professor in the Departments of Electrical and Computer Engineering and
of BioEngineering at Northeastern University\, where he is also affiliate
d with the Mathematics and the Chemical Engineering departments. Since 200
6\, he has been a Research Affiliate at the Laboratory for Information and
Decision Systems\, MIT\, and since 2018 he has been a Faculty Member in t
he Program in Therapeutic Science at Harvard Medical School.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/52/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniele Astolfi (LAGEPP\, University of Lyon 1\, France)
DTSTART:20250319T160000Z
DTEND:20250319T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/54
DESCRIPTION:Title: Incremental stability and ISS: analysis and design\nby Dani
ele Astolfi (LAGEPP\, University of Lyon 1\, France) as part of Input-to-S
tate Stability and its Applications\n\n\nAbstract\nWe revisit the notion o
f incremental stability and ISS for nonlinear systems. First\, we show tha
t incremental stability properties are exponential almost everywhere. Next
\, we briefly revise existing results\, including contraction metric appro
aches\, Lyapunov functions and Finsler-Lyapunov function approaches.\nBase
d on a contraction metric approach\, we show how to construct feedback Lay
punov functions ensuring incremental ISS properties for the closed-loop dy
namics. Finally\, we show two applications of incremental properties: regu
lation and synchronization.\n\nBiography:\nDaniele Astolfi received
the B.S. and M.S. degrees in automation engineering from the University o
f Bologna\, Italy\, in 2009 and 2012\, respectively. He obtained a joint P
h.D. degree in Control Theory from the University of Bologna (Italy) and f
rom Mines ParisTech (France)\, in 2016. Afterwards he spent two years at C
RAN\, Nancy (France) as a postdoc researcher. Since 2018\, he is a CNRS Re
searcher at LAGEPP\, Lyon\, France. He was a recipient of the 2016 Best It
alian Ph.D. Thesis Award given by SIDRA and nominated for the best student
paper award at ECC16 and best paper award at NOLCOS2019. He serves as Ass
ociate Editor for Automatica since 2018 and for EJC since 2023. His resear
ches focus on nonlinear systems\, observer's design\, output regulation\,
and control of complex systems described by PDEs\, hybrid dynamics.\n\n
References:\n
\nIncremental Stability and ISS\n
\n- Angeli (2002
). A Lyapunov approach to incremental stability properties. IEEE TAC.
\
n- Forni\, Sepulchre (2013). A differential Lyapunov framework for contrac
tion analysis. IEEE TAC.
\n- Andrieu\, Jayawardhana\, Praly (2016)
. Transverse exponential stability and applications. IEEE TAC.
\n- Lohm
iller\, Slotine\, (1998). On contraction analysis for non-linear syste
ms. Automatica.
\n- Simpson-Porco\, Bullo (2014). Contraction theory o
n Riemannian manifolds. S&CL.
\n- Kawano\, Besselink (2024). Increme
ntal versus differential approaches to exponential stability and passivity
. IEEE TAC.
\n- Davydov\, Jafarpour\, Bullo (2022). Non-Euclidean co
ntraction theory for robust nonlinear stability. IEEE TAC.
\n- Sontag
(2010). Contractive systems with inputs. MSTCSP.
\n- Giaccagli\, Astolf
i\, Andrieu (2023). Further results on incremental input-to-state stabilit
y based on contraction-metric analysis. IEEE CDC.\n\nControl Contraction M
etrics\n
\n- Manchester\, Slotine (2017). Control contraction metrics:
Convex and intrinsic criteria for nonlinear feedback design. IEEE TAC.
\n- Giaccagli\, Andrieu\, Tarbouriech\, Astolfi (2023). LMI conditions fo
r contraction\, integral action\, and output feedback stabilization for a
class of nonlinear systems. Automatica.
\n- Kawano\, Van Der Schaft\,
Scherpen (2024). Youla-Kucera parametrization in the contraction framewor
k. IEEE TAC.
\n- Astolfi\, Andrieu (2024). Contracting infinite-gain m
argin feedback and synchronization of nonlinear systems. In Hybrid and Net
worked Dynamical Systems: Modeling\, Analysis and Control.
\n- Giaccagl
i\, Zoboli\, Astolfi\, Andrieu\, Casadei (2024). Synchronization i
n networks of nonlinear systems: Contraction analysis via Riemannian metri
cs and deep-learning for feedback estimation. IEEE.
\n\nIncremental Bac
kstepping and Forwarding\n
\n- Andrieu\, Jayawardhana\, Tarbouriech (20
18). Some results on exponential synchronization of nonlinear systems. IEE
E TAC.
\n- Zamani\, van de Wouw\, Majumdar (2013). Backstepping cont
roller synthesis and characterizations of incremental stability. S\\&CL.\n- Giaccagli\, Astolfi\, Andrieu\, Marconi (2022). Sufficient condi
tions for global integral action via incremental forwarding for input-affi
ne nonlinear systems. IEEE TAC.
\n- Giaccagli\, Astolfi\, Andrieu\, Ma
rconi (2024). Incremental stabilization of cascade nonlinear systems and h
armonic regulation: a forwarding-based design. IEEE TAC.\n\nSynchronizatio
n\n
\n- Scardovi\, Sepulchre (2009). Synchronization in networks of ide
ntical linear systems. Automatica.\n- Jayawardhana\, Tarbouriech (2018). S
ome results on exponential synchronization of nonlinear systems. IEEE TAC.
\n- Astolfi\, Andrieu (2024). Contracting infinite-gain margin feedba
ck and synchronization of nonlinear systems. In Hybrid and Networked Dynam
ical Systems: Modeling\, Analysis and Control.
\n- Giaccagli\, Zoboli\
, Astolfi\, Andrieu\, Casadei (2024). Synchronization in networks of
nonlinear systems: contraction analysis via Riemannian metrics and deep-l
earning for feedback estimation. IEEE TAC.
\n- Cellier-Deveux\, Astolfi
\, Andrieu (2025). Edges’ Riemannian energy analysis for synchronization
of multi-agent nonlinear systems over undirected weighted graphs. Automat
ica 2025.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sergey Dashkovskiy (University of Würzburg\, Germany)
DTSTART:20250514T150000Z
DTEND:20250514T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/55
DESCRIPTION:Title: Small-gain theorem for two linear interconnected systems. Is th
ere anything new?\nby Sergey Dashkovskiy (University of Würzburg\, Ge
rmany) as part of Input-to-State Stability and its Applications\n\n\nAbstr
act\nConsider two linear asymptotically stable systems. The classical smal
l-gain theorem says that their interconnection is stable\, if the interact
ion between them is weak in some sense.\n\nIf the interaction intensity ch
anges with time\, then extensions of the classical small-gain theorem (als
o for nonlinear systems) provide sufficient stability conditions.\n\nBy me
ans of examples we demonstrate that existing results are conservative or e
ven useless in certain practical situations.\n\nIn collaboration with Ivan
Atamas and Vitalii Slynko we have developed a new small-gain theorem base
d on a new notion of gains and on a new construction of a Lyapunov functio
n for the interconnection.\n\nWe present these results and demonstrate tha
t our new small-gain condition is less conservative than existing results.
\n\nBiography:\nSergey Dashkovskiy received the M.Sc. degree in app
lied mathematics in 1996 from the Lomonossov University of Moscow and Ph.D
. degree in Mathematics in 2002 from the University of Jena. He has got hi
s habilitation (venia legendi) in Mathematics in 2009 from the university
Bremen. He held positions at the Arizona State University\, the University
of Bayreuth and the University of Applied Scienses Erfurt. Since 2016 he
is professor and head of the research group Dynamics and Control at the In
stitute for Mathematics\, University of Würzburg. His research interests
are in stability theory of dynamical systems and networks. He is editorial
board member of several journals related to this research area\, in parti
cular\, of IEEE Transactions on Automatic Control and Nonlinear Analysis:
Hybrid Systems.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/55/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sahiba Arora (University of Hannover\, Germany)
DTSTART:20250507T150000Z
DTEND:20250507T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/56
DESCRIPTION:Title: Integral ISS for linear infinite-dimensional systems\nby Sa
hiba Arora (University of Hannover\, Germany) as part of Input-to-State St
ability and its Applications\n\n\nAbstract\nThis talk explores integral-to
-integral input-to-state stability (ISS) for infinite-dimensional linear s
ystems in $L^p$-spaces. We investigate the interplay between integral ISS\
, admissibility\, and maximal regularity of Cauchy problems. Additionally\
, we demonstrate the application of Lyapunov functions in analysing ISS in
integral norms\, highlighting their utility in assessing system stability
.\n\nBibliography:\nSahiba Arora is a postdoctoral researcher at Le
ibniz\nUniversity Hannover. She earned her PhD at TU Dresden under Ralph\n
Chill's supervision. Previously\, she held a postdoctoral position at the\
nUniversity of Twente\, working with Felix Schwenninger and supported by\n
the DFG's Walter Benjamin program. Her research interests include\noperato
r semigroups\, ordered Banach spaces\, infinite-dimensional systems\ntheor
y\, and operator theory.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/56/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christoph Kawan (InMach Intelligente Maschinen GmbH\, Ulm\, German
y)
DTSTART:20250528T150000Z
DTEND:20250528T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/57
DESCRIPTION:Title: The Small-Gain Condition for Infinite Networks\nby Christop
h Kawan (InMach Intelligente Maschinen GmbH\, Ulm\, Germany) as part of In
put-to-State Stability and its Applications\n\n\nAbstract\nIn recent years
\, attempts have been made to extend ISS small-gain theorems from finite n
etworks to countably infinite\, locally finite networks. Under specific as
sumptions about the subsystems and the ISS formulation\, corresponding inf
inite-dimensional small-gain results have been proven. However\, concernin
g these assumptions\, the results are still too narrow to be considered a
full extension of the state-of-the-art for finite networks. We take a step
to closing this gap by a thorough investigation of various monotone opera
tors associated with an infinite network and a specific ISS formulation. O
ur results shed more light on the theory of finite networks\, yield comple
te characterizations of the small-gain condition for specific ISS formulat
ions and show which obstacles have to be overcome to obtain a complete the
ory for the most general case.\n\nBiography: \nChristoph Kawan rece
ived the Diploma and Ph.D. degree in mathematics from the University of Au
gsburg\, Germany.\nAs a post-doctoral researcher specialized in dynamical
systems and control theory\, he worked at the Courant Institute of Mathema
tical Sciences of NYU (New York)\, the University of Passau and at LMU Mun
ich. He is the author of the book "Invariance Entropy for Deterministic Co
ntrol Systems - An Introduction" (Lecture Notes in Mathematics 2089. Sprin
ger\, 2013) and winner of the IEEE CSS George S. Axelby Outstanding Paper
Award in 2023. Since January 2022\, he works at InMach Intelligent Machine
s GmbH in Ulm\, Germany\, where he gained additional expertise in sensor s
ystems\, image processing\, path planning\, mathematical modeling of vehic
le dynamics and controller design for service robots and utility vehicles.
\n\nReferences:
\n- C. Kawan. The Small-Gain Condition for Infi
nite Networks. arXiv preprint arXiv:2503.03925 (2025).
\n- C. Kawan\, M
. Zamani. A Lyapunov-based small-gain theory for infinite\nnetworks via in
finite-dimensional gain operators. SIAM Journal on Control\nand Optimizati
on 61\, no. 3\, 1778–1804\, 2023.
\n- C. Kawan\, A. Mironchenko\, M.
Zamani. A Lyapunov-based ISS small-gain theorem for infinite networks of n
onlinear systems. IEEE Transactions on Automatic Control 68\, no. 3\, 1447
–1462\, 2023.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/57/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Frédéric Mazenc (L2S CentraleSupélec\, France)
DTSTART:20250430T150000Z
DTEND:20250430T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/58
DESCRIPTION:Title: A stability analysis technique called trajectory-based approach
.\nby Frédéric Mazenc (L2S CentraleSupélec\, France) as part of Inp
ut-to-State Stability and its Applications\n\n\nAbstract\nWe present a rec
ent stability analysis technique for broad families of nonlinear dynamical
systems. It is called ‘trajectory based approach’ and\, in contrast w
ith Lyapunov based approaches\, it involves verifying certain inequalities
along solutions of systems. It is especially useful when systems with del
ays and discontinuities are studied. We show how the technique can be used
to prove results under the condition that a time-varying inequality of Ha
lanay’s type is satisfied. We show that the technique applies to a wide
range of systems\, notably time-varying systems with time-varying delay\,
systems with impulses\, and systems resulting from the design of finite-ti
me observers. We also explain how the technique yields ISS estimates when
inputs are present.\n\nBiography: \nFrédéric Mazenc received his
Ph.D. in Automatic Control and Mathematics from the CAS at Ecole des Mines
\nde Paris in 1996. He was a Postdoctoral Fellow at CESAME at the Universi
ty of Louvain in 1997. From\n1998 to 1999\, he was a Postdoctoral Fellow a
t the Centre for Process Systems Engineering at Imperial\nCollege. He was
a CR at INRIA Lorraine from October 1999 to January 2004. From 2004 to 200
9\, he was a\nCR1 at INRIA Sophia-Antipolis. Since 2010\, he has been a CR
1 and next a DR2 at INRIA Saclay. He received a\nbest paper award from the
IEEE Transactions on Control Systems Technology at the 2006 IEEE Conferen
ce\non Decision and Control. His current research interests include nonlin
ear control theory\, differential equations\nwith delay\, robust control\,
and microbial ecology. He has more than 300 peer\nreviewed publications.
Together with Michael Malisoff\, he authored a research\nmonograph entitle
d Constructions of Strict Lyapunov Functions in the Springer\nCommunicatio
ns and Control Engineering Series.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/58/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marcello Farina (Politecnico di Milano\, Italy)
DTSTART:20250416T150000Z
DTEND:20250416T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/59
DESCRIPTION:Title: Stability analysis of neural network (NN) based control systems
via Linear Matrix Inequalities with application to data-driven design of
NN controllers with closed-loop guarantees\nby Marcello Farina (Polite
cnico di Milano\, Italy) as part of Input-to-State Stability and its Appli
cations\n\n\nAbstract\nEstablishing sound stability conditions for NN-base
d control systems is fundamental for their secure and proper operation. Th
eoretical properties\, such as the incremental input-to-state stability\,
can be actually exploited to guarantee the properties of NNs and for the d
esign of stabilizing closed-loop control systems. The seminar provides a u
nifying framework\, based on matrix inequality tools\, for the analysis of
the stability properties of NNs and for the (possibly data-based) design
of control systems which include NNs as the plant under control and/or the
controller.\nIndeed\, incremental input-to-state stability can be enforce
d (e.g.\, during the NN training or controller design processes)\, through
simple linear matrix inequalities (LMIs) for a rather general class of NN
s. These conditions are exploited for control design\, guaranteeing the ro
bust stability and desired performances of the control system in a data-ba
sed fashion. To do so\, we resort to set-membership identification techniq
ues and to the virtual reference feedback tuning approach.\n\nBiography
:\nMarcello Farina is Associate Professor at Politecnico di Milano sin
ce December 2014.\nHe received the Master degree in Electronic Engineering
in 2003 from the Politecnico di Milano. During hi PhD studies\, he has wo
rked at the Italian metrological primary Institute Istituto Nazionale Rice
rche in Metrologia and he has been visiting scholar at the Institute for S
ystems Theory and Automatic Control (IST)\, University of Stuttgart\, Germ
any\, under the supervision of Prof. Frank Allgoewer. He obtained the Ph.D
. in Information Engineering in 2007.\n\nHis research interests include bo
th methodological and applicative issues.\nFrom the theoretical side\, he
has contributed in the fields of Model Predictive Control\, distributed co
ntrol design and distributed state estimation\, and more recently to the a
nalysis and design of control systems based on recurrent neural networks.\
nFrom the application side\, he is currently leading projects on the devel
opment of mobile and assistive robotic technologies. For instance\, he is
Principal Investigator of the project BUDD-e: Blind assistive aUtonomous D
roid Device and of Local Principal Investigator the project Control of Ass
istive Robots in crowded Environments (CARE).\n\nReferences:\n\n- W
. D'Amico\, A. La Bella\, and M. Farina. An Incremental Input-to-State Sta
bility Condition for a Class of Recurrent Neural Networks. IEEE Transactio
ns on Automatic Control. Vol. 69\, Issue 4\, 2024.
\n- W. D'Amico\, A.
La Bella\, F. Dercole\, and M. Farina. Data-based control design for nonli
near systems with recurrent neural network-based controllers. IFAC-PapersO
nLine\, Vol. 56\, Issue 2\, 2023.
\n- A. La Bella\, W. D'Amico\; M. Far
ina. Data-driven control of echo state-based recurrent neural networks wit
h robust stability guarantees. Systems & Control Letters. Volume 195\, pap
er n. 105974\, 2025.
\n- D. Ravasio\, M. Farina\, A. Ballarino. LMI-Bas
ed Design of a Robust Model Predictive Controller for a Class of Recurrent
Neural Networks With Guaranteed Properties. IEEE Control Systems Letters\
, vol. 8\, pp. 1126-1131\, 2024.
\n- A. La Bella\, M. Farina\, W. D'Ami
co\, L. Zaccarian. Regional stability conditions for recurrent neural netw
ork-based control systems. Automatica. Volume 174\, paper n. 112127\, 2025
.
\n- D. Ravasio\, M. Farina\, A. La Bella\, A. Ballarino Recurrent neu
ral network-based robust control systems with closed-loop regional increme
ntal ISS and application to MPC design. Submitted at IEEE Transactions on
Automatic Control.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/59/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Torbjørn Cunis (University of Stuttgart\, Germany)
DTSTART:20250521T150000Z
DTEND:20250521T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/60
DESCRIPTION:Title: Characterizations of Input-to-State Stability in Nonlinear Opti
mization Algorithms\nby Torbjørn Cunis (University of Stuttgart\, Ger
many) as part of Input-to-State Stability and its Applications\n\n\nAbstra
ct\nNonlinear optimization has become increasingly involved in the guidanc
e and control of dynamic systems. Its applications include optimal path pl
anning\, collision avoidance\, model predictive control\, and extremum see
king. This has motivated the development of an algorithmic systems theory\
, which studies the stability and robustness of optimization algorithms as
dynamic systems. \nThis talk focuses on the relationship between input-to
-state stability of nonlinear optimization under perturbation and (strong)
metric regularity of the Karush—Kuhn—Tucker system of necessary condi
tions. Rooted in variational analysis\, metric regularity is a notion of L
ipschitz stability for a primal-dual solution under perturbations. It has
played a prominent role in analyzing Newton-type methods for optimization\
, including sequential quadratic programming and augmented Lagrangian meth
ods. In my talk\, I characterize strong metric regularity by necessary and
sufficient optimality conditions. Moreover\, I show that strong metric re
gularity implies\, but is stronger than\, small-input input-to-state stabi
lity of a prototypical Newton method. These results show that metric regul
arity plays a significant role in the systems theory of nonlinear optimiza
tion algorithms.\n\nBiography:\nTorbjørn Cunis received his doctor
al degree in systems and control from ISAE-Supaéro\, University of Toulou
se\, in 2019. Before that\, he studied computer science\, aerospace comput
er engineering\, and automation engineering at the University of Würzburg
and RWTH Aachen University.\nSince 2021\, he has been a lecturer (Akademi
scher Rat a.Z.) at the University of Stuttgart Institute of Flight Mechani
cs and Controls and an adjunct researcher at the University of Michigan Ae
rospace Department. He was a researcher at ONERA – The French Aerospace
Lab (with Laurent Burlion) from 2016 to 2019 and a research fellow at the
University of Michigan (with Ilya Kolmanovsky) from 2019 to 2021. His rese
arch focuses on algorithmic systems and control theory\, in particular\, n
onlinear optimization algorithms and verifiable nonlinear control systems.
\nDr. Cunis is a fellow of the Young ZiF at the Centre for Interdisciplina
ry Research at the University of Bielefeld.\n\nReferences:
\n[1]
T. Cunis and I. Kolmanovsky\, ‘Input-to-State Stability of Newton Metho
ds for Generalized Equations in Nonlinear Optimization’\, in 2024 IEEE C
onference on Decision and Control\, Milano\, 2024\, pp. 5950–5956. doi:
10.1109/CDC56724.2024.10885904.
\n[2] T. Cunis and I. Kolmanovsky\, ‘
Inexactness in Bilevel Nonlinear Optimization: A Gradient-free Newton’s
Method Approach’\, in Symposium on Systems Theory in Data and Optimizati
on\, Stuttgart\, 2024.
\n[3] T. Cunis and I. Kolmanovsky\, ‘Input-to-
State Stability of a Bilevel Proximal Gradient Descent Algorithm’\, in 2
2nd IFAC World Congress\, Yokohama\, 2023\, pp. 7474–7479. doi: 10.1016/
j.ifacol.2023.10.633.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/60/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nikolaos Bekiaris-Liberis (Technical University of Crete\, Greece)
DTSTART:20250604T150000Z
DTEND:20250604T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/61
DESCRIPTION:Title: Micro-macro PDE control under implementation limitations of lar
ge-scale transport systems\nby Nikolaos Bekiaris-Liberis (Technical Un
iversity of Crete\, Greece) as part of Input-to-State Stability and its Ap
plications\n\n\nAbstract\nAlthough “transport” may imply different not
ions for different scientific fields\, the feature of incorporation of int
eracting system components through which “information” is propagated r
emains invariant. I will present control-theoretic results for biological
transport systems\, which describe epidemics spreading dynamics (via peopl
e transport) and cardiovascular flow dynamics (via blood transport). In pa
rticular\, I will present numerical implementations of macroscopic\, coupl
ed crowd flow - epidemics spreading processes\, subject to different macro
-control measures\; while studying blood transport stability in the presen
ce of stenosis\, which may be utilized to quantify medically relevant diag
nostic indices. I will then present computationally tractable control desi
gns for large-scale hyperbolic PDEs (describing biological transport syste
ms dynamics)\, whose complexity does not grow with the number of PDE syste
ms components. I will also present control designs for systems subject to
delays\, quantization\, and switchings\, phenomena that may negatively aff
ect digital implementations of feedback control laws. \n\nBiography:\nNikolaos Bekiaris-Liberis received the Ph.D. degree in aerospace engine
ering from University of California\, San Diego in 2013. From 2013 to 2014
\, he was a Post-Doctoral Researcher with University of California\, Berke
ley. From 2019 to 2022\, he was an Assistant Professor\, from 2017 to 2019
\, he was a Marie Sklodowska-Curie Fellow\, and from 2014 to 2017\, he was
a Research Associate with the Technical University of Crete\, Greece\, wh
ere he is currently an Associate Professor with the Department of Electric
al and Computer Engineering. His research interests include nonlinear dela
y\, switched\, and distributed parameter systems\, and their applications
to transport systems.\n\nNikolaos Bekiaris-Liberis serves as Associate Edi
tor for Automatica and as Senior Editor for IEEE Transactions on Intellige
nt Transportation Systems. He received the Chancellor's Dissertation Medal
in Engineering from University of California\, San Diego in 2014 and the
George N. Saridis Outstanding Research Paper Award in 2019 (from IEEE Inte
lligent Transportation Systems Society). He was a recipient of a 2016 Mari
e Sklodowska-Curie Individual Fellowship Grant and he received a 2022 Euro
pean Research Council (ERC) Consolidator Grant.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/61/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Patrick Bachmann (University of Bayreuth\, Germany)
DTSTART:20250423T150000Z
DTEND:20250423T160000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/63
DESCRIPTION:Title: Characterization of input-to-output stability for infinite dime
nsional systems\nby Patrick Bachmann (University of Bayreuth\, Germany
) as part of Input-to-State Stability and its Applications\n\n\nAbstract\n
Input-to-state stability can be extended to systems with outputs by the no
tion of input-to-output stability (IOS). IOS combines the uniform global a
symptotic stability of the output dynamics with its robustness with respec
t to external inputs.\nWe provide a superposition theorem for IOS of a bro
ad class of nonlinear infinite-dimensional systems with outputs including
both continuous-time and discrete-time systems.\nOn the path to achieve th
is result\, we introduce and examine several novel stability and attractiv
ity concepts for infinite dimensional systems with outputs\, e.g.\, criter
ia for the uniform limit property for systems with outputs\, several of wh
ich are new already for systems with full-state output. Moreover\, we prov
ide superposition theorems for systems which satisfy both the output-Lagra
nge stability property (OL) and IOS\, give a sufficient condition for OL a
nd characterize ISS in terms of IOS and input/output-to-state stability.\n
Finally\, by means of counterexamples\, we illustrate the challenges appea
ring on the way of extension of the superposition theorems in the literatu
re to infinite-dimensional systems with outputs.\n\n Biography: \nP
atrick Bachmann received his Bachelor's degree in Business Mathematics at
the University of Mannheim\, Germany\, in 2015 and his Master's degree in
Mathematics at the Karlsruhe Institute of Technology\, Germany\, in 2018.
He worked as a research assistant at the Technical University of Kaisersla
utern\, Germany\, and the University of Würzburg\, Germany. Currently\, h
e is working at the University of Bayreuth\, Germany\, while pursuing his
PhD degree in Mathematics under supervision of Sergey Dashkovskiy and Andr
ii Mironchenko. His research interests include impulsive systems\, stabili
ty and control theory\, Lyapunov functions\, and infinite-dimensional syst
ems.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/63/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chris Guiver (Edinburgh Napier University\, United Kingdom)
DTSTART:20250326T160000Z
DTEND:20250326T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/64
DESCRIPTION:Title: Passivity theorems for forced Lur'e inclusions and equations\,
and consequent entrainment-type properties\nby Chris Guiver (Edinburgh
Napier University\, United Kingdom) as part of Input-to-State Stability a
nd its Applications\n\n\nAbstract\nI will discuss recent input-to-state st
ability results for a class of forced differential inclusions\, so-called
Lur’e inclusions. One motivation is to obtain semi-global incremental in
put-to-state stability results for systems of forced Lur’e differential
equations. The results are in the spirit of the passivity theorem from con
trol theory as both the linear and nonlinear components of the Lur’e inc
lusion (or equation) are assumed to satisfy passivity-type conditions. \n\
nThese results provide a basis for the analysis of forced Lur’e differen
tial equations subject to (almost) periodic forcing terms and\, roughly sp
eaking\, ensure the existence and attractivity of (almost) periodic state-
and output-responses\, comprising another focus of the present work. One u
ltimate aim is to establish a robust and rigorous theoretical foundation f
or a well-defined and tractable “frequency response” of forced Lur’e
systems.\n\nBiography:\nChris Guiver is an academic working in the
UK in mathematical systems and control theory\, coming to the subject fro
m a mathematics background. He obtained a Mmath (mathematics) and Ph.D. in
mathematics in 2008 and 2012\, respectively\, both from the University of
Bath. He was a postdoctoral researcher at the University of Exeter betwee
n 2012 and 2015. Between 2016 and 2020 he was a Lecturer in Applied Mathem
atics at the University of Bath\, and since 2020 he holds the position of
Lecturer at Edinburgh Napier University. He is a senior member of the IEEE
\, and organises the UK national Mathematical Systems and Control Theory N
etwork.\n\nHe has worked in a number of areas\, including: the stability t
heory of nonlinear control systems using Input-to-State Stability concepts
\; the application of control-theoretic concepts in mathematical ecology a
nd biology\, and\; distributed-parameter (infinite-dimensional) control sy
stems. Earlier in his career he conducted research in model order reductio
n of linear control systems by balanced truncation and its variants\, in b
oth the finite- and infinite-dimensional settings.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/64/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Romain Postoyan (University of Lorraine\, Nancy\, France)
DTSTART:20251126T160000Z
DTEND:20251126T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/68
DESCRIPTION:Title: Estimation of the minimum and maximum states of charge of lithi
um-ion battery packs: A hybrid approach\nby Romain Postoyan (Universit
y of Lorraine\, Nancy\, France) as part of Input-to-State Stability and it
s Applications\n\n\nAbstract\nMonitoring the minimum and maximum states of
charge (SOC) in lithium-ion battery packs is key to ensuring safe and rel
iable long-term operation. The challenge is that these SOCs cannot be dire
ctly measured and their corresponding cells within the pack may change wit
h time. We will see in this talk a a hybrid scheme that estimates the mini
mum and maximum SOCs within a battery pack given by the series interconnec
tion of equivalent circuit models. The dimension of the hybrid estimator i
s independent of the number of cells\, which makes it particularly attract
ive for large battery packs. Moreover\, and key for this seminar series\,
the estimator is endowed with global ISS properties. The stability analysi
s involves cascade system arguments and the use of a non-smooth Lyapunov f
unction. We will finally illustrate the efficiency of the estimator on num
erical simulations and compare it with state-of-the-art techniques\, which
will demonstrate its benefits either in terms of computation time or esti
mates accuracy.\n\nBiography:\nRomain Postoyan received the ‘‘I
ngénieur’’ degree in Electrical and Control Engineering from ENSEEIHT
(France) in 2005. He obtained the M.Sc. by Research in Control Theory & A
pplication from Coventry University (United Kingdom) in 2006 and the Ph.D.
in Control Engineering from Université Paris-Sud (France) in 2009. In 20
10\, he was a research assistant at the University of Melbourne (Australia
). Since 2011\, he is a CNRS researcher at the ‘‘Centre de Recherche e
n Automatique de Nancy ’’ (France). He received the ‘Habilitation à
Diriger des Recherches (HDR) ’’ in 2019 from Université de Lorraine
(Nancy\, France). He serves/served as an associate editor for the journals
: IEEE Transactions on Automatic Control\, Automatica\, IEEE Control Syste
ms Letters and IMA Journal of Mathematical Control and Information\; and g
uess managing editor for NAHS special issue on event- and self-triggered c
ontrol (2024). His research interests include hybrid systems\, dynamic pro
gramming\, and nonlinear estimation.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/68/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jorge Poveda (University of California\, San Diego\, USA)
DTSTART:20251119T160000Z
DTEND:20251119T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/69
DESCRIPTION:Title: Lyapunov-based Interconnection Tools for Fixed-Time Input-to-St
ate Stable Systems: Singular Perturbations and Small-Gain Theorems\nby
Jorge Poveda (University of California\, San Diego\, USA) as part of Inpu
t-to-State Stability and its Applications\n\n\nAbstract\nWe develop new an
alytical tools for establishing fixed-time stability in nonlinear intercon
nected dynamical systems. First\, we extend the classical composite Lyapun
ov method\, widely used for the analysis of singularly perturbed systems\,
and demonstrate that analogous constructions can be applied to study fixe
d-time stability in two-time-scale systems. In particular\, we show that w
hen the time-scale separation is sufficiently large\, and the associated b
oundary-layer and reduced subsystems admit a suitable class of Lyapunov fu
nctions\, the overall interconnected system inherits fixed-time stability
properties. Moreover\, when the dynamics depend on an external input\, ana
logous results are derived in the context of fixed-time input-to-state sta
bility. Subsequently\, we introduce a Lyapunov-based small-gain theorem ta
ilored for fixed-time stability analysis in interconnected systems without
time-scale separation. This result provides a unified framework applicabl
e to a broader class of feedback interconnected systems. We demonstrate th
e applicability of the proposed tools through examples in algorithmic desi
gn for feedback optimization and regulation. Finally\, we discuss extensio
ns for hybrid dynamical systems and present preliminary results on fixed-t
ime stability analysis for hybrid differential inclusions.\n\nBiography
:\nJorge I. Poveda is an Associate Professor in the Department of Elec
trical and Computer Engineering at the University of California\, San Dieg
o\, where he also serves as Associate Director of the Center for Control S
ystems and Dynamics. Before joining UCSD in 2022\, he was an Assistant Pro
fessor at the University of Colorado Boulder (2019-2022) and a Postdoctora
l Fellow at Harvard University (2018). He obtained his M.S. and Ph.D. degr
ees in Electrical and Computer Engineering from the University of Californ
ia\, Santa Barbara\, in 2016 and 2018\, respectively\, under the supervisi
on of Andrew R. Teel. During this time\, he was also a Research Intern at
Mitsubishi Electric Research Laboratories in 2016 and 2017. He holds dual
B.S. degrees in Electronics Engineering and Mechanical Engineering from th
e University of Los Andes\, Colombia. He is the recipient of the CRII and
CAREER Awards from the NSF\, the Young Investigator Awards from AFOSR and
SHPE\, the 2023 Donald P. Eckman Award from the American Automatic Control
Council\, and the UCSB-CCDC Outstanding Scholar Fellowship and Best Ph.D.
Dissertation Awards. He has also received several Best Paper and Best Pap
er Finalist awards with his students and colleagues\, including recognitio
ns from IEEE Transactions on Control of Network Systems (2023)\, the Ameri
can Control Conference (2024)\, the IEEE Conference on Decision and Contro
l (2017\, 2021)\, and the IFAC Conference on Analysis and Design of Hybrid
Systems (2024). He serves as Associate Editor for Automatica\, NAHS\, and
IEEE LCSS.\n\nReferences:
\n- Tang\, Krstic\, Poveda\, "On Fixe
d-Time Stability for a Class of Singularly Perturbed Systems Using Composi
te Lyapunov Functions"\, American Control Conference\, 2024 (https://ieeex
plore.ieee.org/document/10644358/).\n
\n- Tang\, Krstic\, Poveda\, "Fix
ed-Time Input-to-State Stability for Singularly Perturbed Systems via Comp
osite Lyapunov Functions"\, IEEE Transactions on Automatic Control\, 2025
(https://ieeexplore.ieee.org/document/11239427). Extended version availabl
e at https://arxiv.org/abs/2412.16797\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/69/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anil Alan (Delft University of Technology\, Netherlands)
DTSTART:20260204T160000Z
DTEND:20260204T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/71
DESCRIPTION:Title: Input-to-State Safety and Control Barrier Functions for Robust
Safety-Critical Systems\nby Anil Alan (Delft University of Technology\
, Netherlands) as part of Input-to-State Stability and its Applications\n\
n\nAbstract\nModern engineering systems increasingly require explicit cons
traint satisfaction\, for which set-theoretic methods provide formal guara
ntees. However\, realistic implementations and model abstractions introduc
e uncertainties that challenge these guarantees and call for a quantitativ
e notion of robustness. Input-to-state safety (ISSf) addresses this need b
y characterizing how safety guarantees degrade under disturbances\, in clo
se analogy with input-to-state stability.\nIn this talk\, I use ISSf as a
unifying framework for robust safety analysis and control design. I first
show how control barrier functions (CBFs) can be used to derive sufficient
conditions for ISSf of nonlinear systems. I then briefly discuss how ISSf
-CBF conditions can be incorporated into optimization-based safety filters
and illustrate the framework through experimental results on a connected
autonomous truck. To mitigate the conservativeness inherent in standard IS
Sf-CBF formulations\, I introduce tunable ISSf-CBFs\, which enable state-d
ependent adjustment of safety margins and naturally support iterative desi
gn and refinement informed by experimental data. I conclude by outlining f
uture directions toward interconnected large-scale systems.\n\nBiograph
y: Anil Alan is a Postdoctoral Researcher at the Delft Center for Syst
ems and Control at TU Delft\, Netherlands. He completed his PhD in Mechani
cal Engineering at the University of Michigan\, USA\, where he was awarded
the Rackham Predoctoral Fellowship\, and holds an MSc from Bilkent Univer
sity\, Turkey. At TU Delft\, he works on an ERC Advanced Grant project wit
h a focus on constraint-satisfaction methods for optimization-based contro
l of large-scale systems. He is the recipient of the Professor Pierre T. K
abamba Award and ASME’s Best Student Paper Award at the American Control
Conference.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/71/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Iasson Karafyllis (National Technical University of Athens)
DTSTART:20251105T160000Z
DTEND:20251105T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/72
DESCRIPTION:Title: The Strange Relation(ship) Between Adaptive Control and Output
Stability Properties\nby Iasson Karafyllis (National Technical Univers
ity of Athens) as part of Input-to-State Stability and its Applications\n\
n\nAbstract\nIn this talk I will try to shed light on the ways that Output
Stability Theory (including IOS\, output asymptotic gain properties\, out
put stability/attractivity notions) affects and is influenced by Nonlinear
Adaptive Control Theory. To this purpose\, I will briefly review recent r
esults on Lyapunov characterizations of output stability properties and I
will present a novel adaptive control scheme: the Deadzone-Adapted-Disturb
ance-Supression (DADS) control scheme. It will be shown that when modern n
onlinear control theory and modern stability theory go hand-in-hand\, unex
pected robustness results can be produced by the careful design of nonline
ar adaptive controllers. The results presented in this talk have been obta
ined by long collaborations with Miroslav Krstic\, Antoine Chaillet and Yu
an Wang.\n\nBiography: \nIasson Karafyllis is a Professor of Mathem
atics in the Department of Mathematics of the National Technical Universit
y of Athens. He is a coauthor of four books and he has written more than 1
00 journal papers. His research interests lie in the stability theory and
feedback stabilization theory of deterministic control systems as well as
in the connection of Mathematical Control Theory with other areas of mathe
matics.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/72/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zhong-Ping Jiang (New York University\, USA)
DTSTART:20251203T160000Z
DTEND:20251203T170000Z
DTSTAMP:20260424T235201Z
UID:ISS-Theory/73
DESCRIPTION:Title: The Nonlinear Small-Gain Theory for Networks and Control\nb
y Zhong-Ping Jiang (New York University\, USA) as part of Input-to-State S
tability and its Applications\n\n\nAbstract\nThe world is nonlinear and li
nked. In this talk\, I will present the origin of the small-gain theory an
d show that it serves as an important systematic tool for addressing two f
undamental problems for networks: When is a dynamical network robustly sta
ble? When can a dynamical network be made robustly stable by feedback? As
an illustration\, we show how the small-gain theory can be applied to unif
y solutions to event-triggered nonlinear control and provide novel solutio
ns to distributed feedback optimization. Finally\, if time permits\, I wil
l discuss briefly learning-based control\, a new direction in control theo
ry\, that aims to integrate machine learning and nonlinear control techniq
ues to relax the conservativeness of small-gain designs.\n\nBiography:<
/b>\nZhong-Ping Jiang received the M.Sc. degree in statistics from the Uni
versity of Paris XI\, France\, in 1989\, and the Ph.D. degree in automatic
control and mathematics from ParisTech-Mines\, France\, in 1993\, under t
he direction of Prof. Laurent Praly.\n\nCurrently\, he is an Institute Pro
fessor in the Department of Electrical and Computer Engineering and an aff
iliate professor in the Department of Civil and Urban Engineering at the T
andon School of Engineering\, New York University. His main research inter
ests include stability theory\, robust/adaptive/distributed nonlinear cont
rol\, robust adaptive dynamic programming\, reinforcement learning and the
ir applications to information\, mechanical and biological systems. In the
se fields\, he has written six books and is the author/co-author of about
600 peer-reviewed journal and conference papers.\n\nProf. Jiang is a recip
ient of the prestigious Queen Elizabeth II Fellowship Award from the Austr
alian Research Council\, CAREER Award from the U.S. National Science Found
ation\, JSPS Invitation Fellowship from the Japan Society for the Promotio
n of Science\, Distinguished Overseas Chinese Scholar Award from the NSF o
f China\, and several best paper awards. He has served as Deputy Editor-in
-Chief\, Senior Editor and Associate Editor for numerous journals\, and is
among the Clarivate Analytics Highly Cited Researchers and Stanford’s T
op 2% Most Highly Cited Scientists. In 2022\, he received the Excellence i
n Research Award from the NYU Tandon School of Engineering. Prof. Jiang is
a foreign member of the Academia Europaea (Academy of Europe) and an ordi
nary member of the European Academy of Sciences and Arts\, and also is a F
ellow of the IEEE\, IFAC\, CAA\, AAIA and AAAS.\n
LOCATION:https://stable.researchseminars.org/talk/ISS-Theory/73/
END:VEVENT
END:VCALENDAR