Bart Besselink receives ERC Consolidator Grant

The research proposal “Contracts for Control System Design (COCOS)” of Bart Besselink will receive 2 Mio € funding by the European Research Council (ERC). The ERC Consolidator Grant is a prestigious research funding program to support researchers who are in the early stages of their independent research careers and have demonstrated significant potential for conducting high-quality research. Bart proposes a new approach for control system design based on contracts, inspired by ideas from software design in computer science. He will develop a contract theory for control system design that includes techniques for the automatic design of component contracts aimed at optimizing system-level performance, and control design for contract satisfaction. The practical relevance of the theory will be tested by case studies in high-tech manufacturing systems and autonomous vehicles, and supported by efficient computational tools.

SCO colloquium: Azka Burohman

Title: Dissipativity-preserving reduced-order modeling from data
 
Abstract: Reduced-order modeling from data with dissipativity preservation is discussed in this talk. Employing the data informativity framework, the dissipativity of all systems consistent with noisy data can be characterized by a data-based linear matrix inequality (LMI). Furthermore, semi-definite programming duality helps us to prove the existence of minimal and maximal solutions to the LMI. As in the classical bounded-real and positive-real balanced truncation, these extremal solutions play a role in the computation of well-approximating reduced-order models carrying the dissipativity property. As an additional advantage of using this balancing-type method, a priori error bounds of the reduced-order models are available.

SCO colloquium: Juan Peypouquet

Title: A speed restart scheme for first order dynamics bearing second order information in time and space

Abstract: We present two techniques that can help stabilize otherwise erratic inertial methods. Combined, they can enhance the performance of accelerated methods, especially for functions with quadratic growth, for which the rate of linear convergence is improved.

SCO colloquium: Amir Shakouri

Title: Prescribed-time control

Abstract: In terms of the user’s knowledge about the settling time, non-asymptotic controllers can be divided into three major categories of finite-time, fixed-time, and prescribed-time approaches. In finite-time schemes, it is only known that the system non-asymptotically converges at a finite time that is generally a function of the initial conditions. Fixed-time schemes provide an upper bound for the settling time, independently of initial conditions. However, in prescribed-time control, the settling time is commanded to the system, which means that the user is not only aware of the convergence moment but can arbitrarily specify it just by changing a parameter. It turns out that another interesting feature of prescribed-time controllers, apart from having an adjustable settling time, is their robustness to unknown dynamics for which no global bounds exist.

In this talk, after reviewing the state-of-the-art, some new unpublished results on the differential Riccati equation approaches to prescribed-time control are discussed (LQR and SDRE-based designs), and it is shown how they can be used for the stabilization of (partially) unknown nonlinear systems.

SCO colloquium: Sutrisno

Title: Singular linear switched systems in discrete time: solution theory, reachability, and duality
 
Abstract: In this talk, solution theory for singular linear switched systems in discreet time with arbitrary switching signals will be presented. Based on the derived solution theory, reachability and controllability characterizations will be discussed for a fixed and known switching signal. Moreover, the duality between reachability and observability of this system class will also be discussed.

SCO colloquium: Hamin Chang

Title: Model reference Gaussian process regression: data-driven output feedback controller

Abstract: Data-driven controls using Gaussian process regression have recently gained much attention. In such approaches, system identification by Gaussian process regression is mostly followed by model-based controller designs. However, the outcomes of Gaussian process regression are often too complicated to apply conventional control designs, which makes the numerical design such as model predictive control employed in many cases. To overcome the restriction, our idea is to perform Gaussian process regression to the inverse of the plant with the same input/output data for the conventional regression. With the inverse, one can design a model reference controller without resorting to numerical control methods. This talk considers single-input single-output (SISO) discrete-time nonlinear systems of minimum phase with relative degree one. It is highlighted that the model reference Gaussian process regression controller is designed directly from pre-collected input/output data without system identification.

SCO colloquium: Arjan van der Schaft

Title: On the legacy of Jan Willems (talk given before for the Control History Forum, CSS Day, October 2022)
 
Abstract: The list of scientific contributions of Jan Willems spans a whole range of topics, including (input-output) stability theory, dissipativity theory, linear geometric control theory, identification, the behavioral approach to systems and control, physical systems theory, open stochastic systems, .. ; see the website https://homes.esat.kuleuven.be/~sistawww/smc/jwillems/ for much more information. In this talk I will focus on two of these topics: dissipativity theory, and the behavioral approach to systems and control. Discussion of the first topic will be partly based on:
 
Introduction by Arjan van der Schaft to Jan C. Willems’, “Dissipative Dynamical Systems,
Part I: General Theory, 50 Years of Dissipativity Theory, IEEE Control Systems Magazine 42 (2), 46-50, 2022,
Part II: Linear Systems With Quadratic Supply Rates, IEEE Control Systems Magazine 42 (3), 32-35, 2022.

SCO colloquium: Anne-Men Huijzer

Title: Networks of memristors and the effective memristor.

Abstract: Memristors, originally introduced by Chua in 1971, are resistors with a memory storage which are defined by a relationship between charge and flux. In this talk, an introduction of memristors will be given after which a way to model networks of memristors will be described. Furthermore, we show that the input output behavior of a network of memristors can be described by a memristor, the so-called effective memristor.

 

SCO colloquium: Kanat Camlibel

Title: Scalable controllability analysis of structured systems
 
Abstract: This talk deals with strong structural controllability of structured networks. A structured network is a family of structured systems (called node systems) that are interconnected by means of a structured interconnection law. The node systems and their structured interconnection law are given by pattern matrices. We will show that a structured network is strongly structurally controllable if and only if an associated structured system is. This structured system will in general have a very large state space dimension, and therefore existing tests for verifying strong structural controllability are not tractable. The results we present circumvent this problem. We show that controllability can be tested by replacing the original network by a new network in which all original node systems have been replaced by (auxiliary) node systems with state space dimensions either 1 or 2. Hence, controllability of the original network can be verified by testing controllability of a structured system with state space dimension at most twice the number of node systems, regardless of the state space dimensions of the original node systems.