Panos J. Antsaklis

University of Notre Dame | ND · Department of Electrical Engineering

This paper considers the problem of decentralized analysis and control synthesis to verify and enforce properties like stability and dissipativity of large-scale networked systems comprised of linear subsystems interconnected in an arbitrary topology. In particular, we design systematic networked system analysis and control synthesis processes that...

Symbolic control problems aim to synthesize control policies for dynamical systems under complex temporal specifications. For such problems, Signal Temporal Logic (STL) is increasingly used as the formal specification language due to its rich expressiveness. Moreover, the degree of satisfaction of STL specifications can be evaluated using ``STL rob...

In this paper, we consider networked systems comprised of interconnected sets of linear subsystems and propose a decentralized and compositional approach to stabilize or dissipativate such linear networked systems via optimally modifying some existing interconnections and/or creating entirely new interconnections. We also extend this interconnectio...

This article focuses on extending, disseminating and interpreting the findings of an IEEE Control Systems Society working group looking at the role of control theory and engineering in solving some of the many current and future societal challenges. The findings are interpreted in a manner designed to give focus and direction to both future educati...

In the article entitled “Distributed synthesis of local controllers for networked systems with arbitrary interconnection topologies” published in the IEEE Transactions on Automatic Control , vol. 66, pp. 683–698, 2021, there were some missing terms in Lemma 1 and the definition of the messenger matrices. Here, we include these terms and suitably...

Several important problems in multi-agent systems, machine learning, data mining, scheduling and others, may be formulated as set function maximization problems subject to cardinality constraints. In such problems, the set (objective) functions of interest often have monotonicity and submodularity properties. Hence, the class of monotone submodular...

Networked systems comprised of interconnected sets of non-linear subsystems appear in many real-world scenarios such as in robotics, communication networks and biochemical processes. In this paper, we develop centralized and decentralized techniques for analyzing and synthesizing such networked systems only using dissipativity properties of individ...

In this paper, we consider the problem of platooning control with mismatched disturbances using the distributed adaptive backstepping method. The main challenge is due to the derivative explosion arising from the involvement of the adaptive laws. To accommodate this, we first propose a novel notion of string stability called \emph{Vector String Sta...

We consider the problem of distributed analysis and control synthesis to verify and ensure properties like stability and dissipativity of a large-scale networked system comprised of linear subsystems interconnected in an arbitrary topology. In particular, we design systematic networked system analysis and control synthesis processes that can be exe...

Dissipativity theory is an important energy-based framework for the analysis and design of control systems using an input–output approach. Quadratic supply rate functions in particular have been of great interest since their introduction by Jan Willems. Quadratic supply rate dissipativity exhibits many interesting properties, including a tighter re...

We consider the problem of on-line evaluation of critical characteristic parameters such as the L_2-gain (L2G), input feedforward passivity index (IFP) and output feedback passivity index (OFP) of non-linear systems using their input-output data. Typically, having an accurate measure of such "system indices" enables the application of systematic co...

Piecewise affine (PWA) systems are widely applied in many practical cases such as the control of nonlinear systems and hybrid dynamics. However, most of the existing PWA control methods have poor scalability with respect to the number of modes and system dimensions and may not be robust to the disturbances in performance. In this paper, we present...

Hybrid dynamical systems contain both time-driven continuous dynamics and event-driven discrete dynamics that interact with each other, and their interactions determine the behavior of the system over time. To fully understand the tight interactions between discrete and continuous dynamics, we need a unified modeling framework. Various models have...

In the optimal control of hybrid systems, a stabilizing control law is designed to optimize, i.e., minimize or maximize, an appropriate performance criterion. Optimal control has been an active research area in Systems and Control, at least, since the 1950s, when seminal contributions such as Pontryagin’s minimum principle and Bellman’s dynamic pro...

Stability is a basic requirement in dynamical systems. Generally speaking, a dynamical system is stable when there exists at least one operating point, typically an equilibrium where the state stays if there is no external stimulus, such that all the state trajectories starting from somewhere nearby will stay close to the operating point at all tim...

So far, we have presented and discussed basic results for the modeling, verification, stability, and optimal control of hybrid systems. These results have been introduced by both the computer science and control engineering communities. The computer science community has been primarily interested in verifying the correctness of embedded codes in th...

The verification of real-time codes implemented in embedded systems is a very important problem, as many of these systems, such as autopilot systems and medical devices, are safety critical and need guarantees of their proper operations (Edwards et al. in Proc IEEE 85(3):366–390, 1997, [1]). These embedded systems are interacting with the physical...

A graduate-level textbook, Hybrid Dynamical Systems provides an accessible and comprehensive introduction to the theory of hybrid systems. It emphasizes results that are central to a good understanding of the importance and role of such systems. The authors have developed the materials in this book while teaching courses on hybrid systems, cyber-ph...

Recent advances in distribution-level phasor measurement unit (D-PMU) technology have enabled the use of voltage phase angle measurements for direct load sharing control in distribution-level microgrid interconnections with high penetration of renewable distributed energy resources (DERs). In particular, D-PMU enabled voltage angle droop control ha...

The event-triggered control problem over lossy communication networks is addressed in this paper. Although packet dropouts have been considered in the implementation of event-triggered controllers, the assumption of protocols that employ acknowledgement messages persists. This paper provides an approach that relaxes such assumption. An event-based...

Experimental determination of protein function is resource-consuming. As an alternative, computational prediction of protein function has received attention. In this context, protein structural classification (PSC) can help, by allowing for determining structural classes of currently unclassified proteins based on their features, and then relying o...

The quest for autonomy has been a pervasive theme in human culture through-out history. In this paper a general definition of autonomous systems is presented and discussed that leads naturally to the establishment of metrics to measure the level of autonomy of a system. This definition is based on the systems ability to achieve goals under uncertai...

We consider the problem of designing distributed controllers to guarantee dissipativity of a networked system comprised of dynamically coupled subsystems. We require that the control synthesis is carried out locally at the subsystem-level, without explicit knowledge of the dynamics of other subsystems in the network. We solve this problem by derivi...

This paper addresses the problem of designing an optimal output feedback controller with a specified controller structure for linear time-invariant (LTI) systems to maximize the passivity level for the closed-loop system, in both continuous-time (CT) and discrete-time (DT). Specifically, the set of controllers under consideration is linearly parame...

This paper investigates the closed-loop $\mathcal{L}_2$ stability of two-dimensional (2-D) feedback systems across a digital communication network by introducing the tool of dissipativity. First, sampling of a continuous 2-D system is considered and an analytical characterization of the $QSR$ -dissipativity of the sampled system is presented. N...

This paper investigates the closed-loop $\mathcal{L}_2$ stability of two-dimensional (2-D) feedback systems across a digital communication network by introducing the tool of dissipativity. First, sampling of a continuous 2-D system is considered and an analytical characterization of the $QSR$-dissipativity of the sampled system is presented. Next,...

This paper addresses the problem of designing an optimal output feedback controller with a specified controller structure for linear time-invariant (LTI) systems to maximize the passivity level for the closed-loop system, in both continuous-time (CT) and discrete-time (DT). Specifically, the set of controllers under consideration is linearly parame...

In this paper, we will discuss how operational limitations affect input-output behaviours of the system. In particular, we will provide formulation for passivity and passivity indices of a nonlinear system given operational limitations on the input and state variables. This formulation is presented in the form of local passivity and indices. We wil...

We consider the problem of designing distributed controllers to guarantee dissipativity of a networked system comprised of dynamically coupled subsystems. Additionally, we require that the control synthesis is carried out locally at the subsystem-level, without explicit knowledge of the dynamics of other subsystems in the network. We solve this pro...

Analysis and resilient design of Cyber-physical Systems have greatly benefited from energy based concepts of passivity and dissipativity. Recently, there has been much research devoted to the use of passivity indices in different components of Cyber-physical systems. Passivity indices are measures of passivity, indicating how passive a system is or...

This paper presents a new data-driven fault identification and controller reconfiguration algorithm. The presented algorithm relies only on the system's input and output data, and it does not require a detailed system description. The proposed algorithm detects changes in the input-output behavior of the system, whether due to faults or malicious a...

In this paper, we will discuss how operational limitations affect input-output behaviours of the system. In particular, we will provide formulations for passivity and passivity indices of a nonlinear system given operational limitations on the input and state variables. This formulation is presented in the form of local passivity and indices. We wi...

We consider the problem of designing distributed controllers to ensure passivity of a large-scale interconnection of linear subsystems connected in a cascade topology, where the control design process needs to be carried out locally at the subsystem-level with no direct knowledge of the dynamics of other subsystems in the interconnection. We presen...

Recent advances in distribution-level phasor measurement unit (D-PMU) technology have enabled the use of voltage phase angle measurements for direct load sharing control in distribution-level microgrid interconnections with high penetration of renewable distributed energy resources (DERs). In particular, D-PMU enabled voltage angle droop control ha...

We consider the problem of guaranteeing transient stability in angle droop controlled microgrid networks where voltage angle measurements from phasor measurement units (PMUs) may be lost. In the event of PMU measurement loss at some microgrids, the network may become unstable if there is a mismatch between load and power generation. To address this...

Compositional control methods are well-suited for the design of large-scale control systems. QSR-Dissipativity and passivity are closely related to stability and may be utilized to show Lyapunov and finite-gain stability for dynamical systems under certain conditions. Additionally, passivity is preserved under feedback and parallel interconnections...

This brief examines the use of a learning control method in a passivity-based framework to control a motorized cycle-rider system with functional electrical stimulation (FES) of the quadriceps muscle groups. FES cycling with motorized assistance has been used in the rehabilitation of people with neurological conditions. The concepts of adaptation a...

Autonomous systems evolve from control systems by adding functionalities that increase the level of system autonomy. It is very important to the research in the field that autonomy be well defined and so in the present paper a precise, useful definition of autonomy is introduced and discussed. Autonomy is defined as the ability of the system to att...

Experimental determination of protein function is resource-consuming. As an alternative, computational prediction of protein function has received attention. In this context, protein structural classification (PSC) can help, by allowing for determining structural classes of currently unclassified proteins based on their features, and then relying o...

A method to passivate a given system by using an input–output transformation matrix is introduced. This matrix generalizes the commonly used methods of series, feedback, and feedforward to passivate a linear or nonlinear system. Through an appropriate design of this matrix, positive passivity indices can be guaranteed for the system. Furthermore, t...

Presents an editorial of the state of the IEEE Transactions on Automatic Control .

This work focuses on the invariance of important properties between continuous and discrete models of systems which can be useful in the control design of large-scale systems and their software implementations. In particular, this paper discusses the relationships between the QSR dissipativity of a continuous state dynamical system and of its abstr...

In this paper, we introduce a passivity-based design framework for event-triggered networked control systems. We consider the effects of network-induced time delays, signal quantization, and data loss in communication links between the plant and controller and show $L_2$ -stability and robustness for the control design. We introduce simple asynchr...

In this paper, we show synchronization for a group of output passive agents that communicate with each other according to an underlying communication graph to achieve a common goal. We propose a distributed event-triggered control framework that will guarantee synchronization and considerably decrease the required communication load on the band-lim...

In this paper, we show synchronization for a group of output passive agents that communicate with each other according to an underlying communication graph to achieve a common goal. We propose a distributed event-triggered control framework that will guarantee synchronization and considerably decrease the required communication load on the band-lim...

The main goal of this study is to extract a set of brain networks in multiple time-resolutions to analyze the connectivity patterns among the anatomic regions for a given cognitive task. We suggest a deep architecture which learns the natural groupings of the connectivity patterns of human brain in multiple time-resolutions. The suggested architect...

This paper summarizes important results useful for controller design of multi-input multi-output systems. The main goal is to characterize the stabilizing controllers that provide a desired response.

We propose a formal design framework for synthesizing coordination and control policies for cooperative multi-agent systems to accomplish a global mission. The global performance requirements are specified as regular languages while dynamics of each agent as well as the shared environment are characterized by finite automata, upon on which a formal...

Indoor climate control of thermal comfort for humans in a residential or commercial building is a major component of building energy management. The goal of optimal temperature and humidity control is to ensure indoor comfort with minimal energy consumption. Model-Based Predictive Control (MBPC) is considered to be one of the most suited solutions...

Presents the introductory editorial for this issue of the publication.

Reports on the 24th Mediterranean Conference on Control and Automation Conference.

We present an approach to passivate a class of discrete time switched nonlinear systems under arbitrary switching. Using switched storage functions, we derive a linear matrix inequality condition for strict input passivity of discrete time switched nonlinear systems. When the switched system is non passive, we design a state feedback controller to...

This chapter considers the problem of stabilization of uncertain systems where feedback measurements are transmitted through a limited bandwidth communication network. An adaptive model-based event-triggered control framework is presented where a model of the plant dynamics is implemented in the controller node which provides estimates of the plant...

In this technical note, symmetries in large-scale dissipative and passive control systems are considered. In the framework of dissipativity and passivity theory, stability conditions for large-scale systems are derived by categorizing agents into symmetry groups and applying local control laws under limited interconnections with neighbors. Building...

The simultaneous heat and moisture transfer in the building envelope has an important influence on the indoor climate and the overall thermal performance of buildings. In this work, the development of a Building Energy Analysis Model (BEAM) predicting whole building heat and moisture transfer is presented. The coupled heat and moisture transfer mod...

In this report, we apply an input-output transformation passivation method, described in our previous works, to an Adaptive Cruise Control system. We analyze the system's performance under a co-simulation framework that makes use of an online optimization method called extremum-seeking to achieve the optimized behavior. The matrix for passivation m...

Input feed-forward output feedback passive (IF-OFP) systems define a great number of dynamical systems. In this report, we show that dissipativity and passivity-based control combined with event-triggered networked control systems (NCS) provide a powerful platform for the design of cyber-physical systems (CPS). We propose QSR-dissipativity, passivi...

This paper focuses on the notions of QSR dissipativity and passivity in hybrid systems. The work presented in this paper can mainly be divided into two parts- (i) feedback and parallel interconnections and, (ii) networks. First, it is shown that the negative feedback interconnection of two QSR dissipative hybrid systems is QSR dissipative. Also, pa...

In our previous work [4], we proposed a learning-based formal top-down design framework to automatically synthesize coordination and control strategies for cooperative multi-agent systems. Our main idea is to decompose a given team mission into individual local tasks and synthesizing local supervisors while guarantee the multi-agent performance by...

In this paper, we consider the following problem: what passivity properties can be inferred for a system by studying only an approximate mathematical model for it. Our results show that an excess of passivity (whether in the form of input strictly passive, output strictly passive or very strictly passive) in the approximate model guarantees a certa...

While most of the work in the literature focuses on stability conditions for event-triggered systems, in this technical note we focus on passivity and passivation of event-triggered feedback interconnected systems of two input feed-forward output-feedback (IF-OF) passive systems. Passivity indices (levels) are used to measure the excess or shortage...

We consider state estimation for multiple plants across a shared communication network. Each linear time-invariant plant transmits information through the common network according to either a time-triggered or an event-triggered rule. For an event-triggered algorithm with CSMA (carrier sense multiple access), each plant is assumed to access the net...