Cooperative output regulation of linear multi-agent systems with communication constraints

This paper investigates the cooperative output regulation problem for heterogeneous linear multiagent systems under fixed communication graphs via event-triggered control. A fully distributed event-triggered dynamic output feedback control law is proposed based on the feedforward design approach. At the same time, a fully distributed dynamic event-triggering mechanism is designed so that each agent can determine when to broadcast its information to its neighbors. Compared with existing related results, both the control law and the event-triggering mechanism in this paper are independent of any global information. It is shown that with the proposed dynamic event-triggered control strategy, the cooperative output regulation problem can be solved in a fully distributed manner by intermittent communication. Moreover, Zeno behavior can be strictly ruled out for each agent. Finally, the effectiveness of the proposed dynamic event-triggered control strategy is validated by a numerical example.

The discrete distributed observer is developed recently to solve the cooperative output regulation problem. The validation of the existing discrete distributed observer depends on the establishment of the communication network. In some practical applications, only the sensor network can be established among all agents. To handle such cases, we propose a sensory feedback-based discrete distributed observer, which depends on the relative output of neighboring agents. In contrast to existing results, the design of the discrete distributed observer and cooperative output regulation analysis should be conducted simultaneously. Resorting to the small-gain theorem, we develop a small-gain condition-based approach and a low-gain-based approach, respectively. By these two approaches, we demonstrate that the discrete distributed observer holds and the cooperative output regulation problem of heterogeneous discrete-time linear multiagent systems can be solved.

In this paper, we consider the cooperative output regulation problem of heterogeneous linear multi-agent systems (MASs) by event-triggered control. We first develop an event-triggering mechanism for leader-following consensus of homogeneous MASs. Then by proposing an internal reference model for each agent, a novel distributed event-triggered control scheme is developed to solve the cooperative output regulation problem of heterogeneous MASs. Furthermore, a novel self-triggered control scheme is also proposed, such that continuous monitoring of measurement errors can be avoided. The feasibility of both proposed control schemes is studied by excluding Zeno behavior for each agent. An example is finally provided to demonstrate the effectiveness of the control schemes.

In this paper, we first propose a self-tuning adaptive distributed observer for a multi-agent system, which is capable of providing the estimation of the leader's signal to various followers without assuming all the followers know the system matrix of the leader and which avoids calculating the observer gain off-line. We then further develop an adaptive distributed control law to solve the cooperative output regulation problem for linear heterogeneous multi-agent systems. This control law offers two advantages in that it makes the least use of the information of the network and the information of the leader system, and it avoids calculating the observer gain.

In this paper, the event-triggered adaptive distributed observer is applied to solve the problem of cooperative output regulation for discrte-time linear multi-agent systems. Firstly, we propose two distributed event-triggered strategies, one is relative threshold event-triggered strategy, the other is switching threshold event-triggered strategy. Then we apply these two event-triggered strategies to an adaptive distributed observer, which does not need each follower to know the leader's matrix information, so it can be fully distributed. Finally, the effectiveness of the method is illustrated by digital simulation.

In this note, the cooperative output regulation problem of heterogeneous linear multi-agent systems is investigated. Our approach is based on internal model and dynamic error feedback among the agents. Under some standard assumptions, the problem is solved by an internal model and a stabilizing H∞ controller. We showed that the exo-signal-free system is stabilized if each controlled agent is robust (in the sense of H∞ norm) to resist the disturbance measured by the second largest eigenvalue of the graph adjacency matrix. Then the synthesis problem is solved using algebraic Riccati equation. Furthermore, we showed that this condition is a generalization of existing results.

This brief focuses on cooperative output regulation (COR) problem for linear multiagent systems (MASs) under the directed topology. The fully distributed event-triggered control protocol is designed to solve COR problem. In order to reduce the communication frequency, the dynamic event-triggered mechanism is proposed by introducing positive internal variable. One main advantage is that the method inherits the advantages of event-triggered control and adaptive control to deal with the COR problem, and does not depend on global information. At last, a numerical example is given in the supplementary material to verify the validity of the obtained results.

Cooperative output regulation problem with faults based on adaptive event-triggered mechanism

The cooperative output regulation of a linear multi-agent system can be viewed as a generalization of the leader-following consensus problem and was studied recently for the case where the system uncertain parameters vary in a sufficiently small neighborhood of their nominal value. This case was handled by the internal model design which converts the problem into a simultaneous eigenvalue placement problem of an augmented multi-agent system. In this paper, we further consider the cooperative robust output regulation problem for a class of minimum phase linear multi-agent systems in the sense that the controller allows the system uncertain parameters to vary in an arbitrarily prescribed compact subset. For this purpose, we introduce a new type of internal model that allows the cooperative robust output regulation problem of the given plant to be converted into a robust stabilization problem of an augmented multi-agent system. We then solve our problem by combining a simultaneous high-gain state feedback control technique and a distributed high-gain observer technique. A special case of our result leads to the solution of the leader-following robust consensus problem for a class of uncertain multi-agent systems. Copyright © 2013 John Wiley & Sons, Ltd.

Event-triggered robust cooperative output regulation for a class of linear multi-agent systems with an unknown exosystem

Cooperative output regulation problem for linear time-delay multi-agent systems under switching network

In this paper, a new distributed model reference adaptive control (MRAC) design framework is proposed for containment control of heterogeneous uncertain multi-agent systems (MAS). Both groups of leaders and followers are considered to have general linear dynamics with the leaders subject to bounded external inputs and the followers subject to uncertain system dynamics. A novel distributed adaptive control protocol is developed under this new framework, which incorporates robust adaptive control with nonlinear compensator techniques to cope with unmeasurable bounded leaders' inputs and uncertain agent dynamics. Convergence of the containment control errors to an arbitrarily adjustable neighborhood of the origin is guaranteed based on the Lyapunov method. The proposed MRAC framework provides a promising alternative solution over the prevailing cooperative output regulation framework for heterogeneous linear MAS containment control. It enables us to handle more general system settings under more stringent control environments with limited accessibility of leaders' information and uncertain follower dynamics.

Adaptive distributed observer for general linear leader systems over periodic switching digraphs

Survey/review study The Cooperative Output Regulation by the Distributed Observer Approach Youfeng Su 1, He Cai 2, and Jie Huang 3,* 1 College of Computer and Data Science, Fuzhou University, Fuzhou 350116, China 2 School of Automation Science and Engineering, South China University of Technology, Guangzhou 510641, China 3 Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong, China * Correspondence: jhuang@mae.cuhk.edu.hk Received: 7 November 2022 Accepted: 13 November 2022 Published: 22 December 2022 Abstract: The cooperative output regulation problem (CORP) is an extension of the leader-following consensus problem of multi-agent systems (MASs), and has been studied by two approaches, namely, the distributed observer (DO) approach and the distributed internal model (DIM) approach. The two approaches are, respectively, the extensions of the classical feedforward control approach and the classical internal model approach (for a single system) to the MASs. This paper overviews the CORP by the DO approach with the emphasis on linear MASs. After formulating the CORP, we present the evolution process of three types of DOs and the corresponding solutions to the CORP. Furthermore, some variants and extensions of the DO approach are also briefly surveyed for completeness.

ABSTRACTIn this paper, we first propose a self-tuning distributed observer for a multi-agent system, which is capable of providing the estimation of the leader's signal to various followers without assuming all the followers know the system matrix of the leader. We then further develop a novel adaptive distributed control law to solve the cooperative output regulation problem for linear heterogeneous multi-agent systems. This control law offers two advantages in that it makes less use of the information of the network as well as the information of the leader and external disturbances, and it avoids calculating the observer gain.