Cooperative Output Regulation Research Articles

Sampled-Data Cooperative Output Regulation: An Adaptive Distributed Continuous-Discrete Observer Approach

This paper studies the sampled-data cooperative output regulation problem for linear multi-agent systems. Firstly, a novel adaptive distributed continuous-discrete observer is established to recover the leader's state, which, on one hand, only relies on the sampling output of the leader, and on the other hand, does not need to store the sampled message from neighbors. Secondly, by solely making use of the digital states of both the agent and the distributed observer, a certainty equivalence control law is synthesized featuring a time-varying feedforward gain. It is rigorously proven that, with this time-varying feedforward gain, the proposed control approach can achieve exponential convergence of the tracking errors given arbitrary time-varying leader's signal, and the upper bound for the sampling intervals is explicitly given. Thirdly, for the class of chain-integrator multi-agent systems, the proposed control approach does not need any restriction on the upper bound of the sampling intervals, and thus would be more practical in certain application scenarios from the perspective of energy saving. The performance of the proposed control approach is validated by the simulation results of inverter-based distributed generation systems.

Fully distributed adaptive cooperative output regulation of heterogeneous multi-agent systems with hybrid event-triggering mechanism

This study focuses on the event-triggered cooperative output regulation problem (CORP) of multi-agent systems with heterogeneous dynamics. Two design criteria are required be achieved: event-triggered communication between agents has strictly positive minimum inter-event time (MIET), and global information with respect to communication topology is not needed to implement the event-triggered control strategy. These two criteria are significant, but cannot be simultaneously satisfied using the relevant existing results. In this work, two event-triggered observers with hybrid triggering conditions are developed to estimate the matrix and state of the exosystem, the MIET is enforced to be positive by incorporating an auxiliary function with decreasing dynamics into the event-triggering mechanism (ETM). This is more stringent than simply removing Zeno behavior and is more useful in engineering applications. Additionally, distributed controllers are developed based on the estimated state and regulator equation. The proposed method, which is better and more useful than the up-to-date results in literature, and can satisfy the two design criteria as mentioned before. Finally, numerical examples are provided to demonstrate the effectiveness.

Cooperative output regulation for networks of hyperbolic systems using adaptive cooperative observers

This paper is concerned with the cooperative output regulation problem for heterogeneous networks of hyperbolic agents. Both the leaders’ output as well as the disturbances are generated by finite-dimensional signal models that are unknown to the followers. An adaptive cooperative reference observer is employed and an infinite-dimensional adaptive cooperative disturbance observer is designed using the backstepping approach to estimate both the states and the signal model parameters. By combining them with a local state feedback regulator, an adaptive cooperative output feedback regulator results. It is shown that the resulting network controlled multi-agent system achieves asymptotic leader–follower output synchronization. The results of the paper are illustrated for a heterogeneous network of three hyperbolic agents in simulations.

Cooperative Output Regulation for Linear Multiagent Systems via Distributed Fixed-Time Event-Triggered Control.

In this article, we consider the cooperative output regulation for linear multiagent systems (MASs) via the distributed event-triggered strategy in fixed time. A novel fixed-time event-triggered control protocol is proposed using a dynamic compensator method. It is shown that based on the designed control scheme, the cooperative output regulation problem is addressed in fixed time and the agents in the communication network are subject to intermittent communication with their neighbors. Simultaneously, with the proposed event-triggering mechanism, Zeno behavior can be ruled out by choosing the appropriate parameters. Different from the existing strategies, both the compensator and control law are designed with intermittent communication in fixed time, where the convergence time is independent of any initial conditions. Moreover, for the case that the states are not available, the output regulation problem can further be addressed by the distributed observer-based output feedback controller with the fixed-time event-triggered compensator and event-triggered mechanism. Finally, a simulation example is provided to illustrate the effectiveness of the theoretical results.

Hybrid Cooperative Output Regulation of Linear Multi-Agent Systems

Hybrid Cooperative Output Regulation of Linear Multi-Agent Systems

Prescribed-Time Cooperative Output Regulation of Heterogeneous Multi-Agent Systems Under Switching DoS Attacks

Prescribed-Time Cooperative Output Regulation of Heterogeneous Multi-Agent Systems Under Switching DoS Attacks

Cooperative Fault-Tolerant Control for a Class of Nonlinear MASs by Resilient Learning Approach.

In this article, a learning-based resilient fault-tolerant control method is proposed for a class of uncertain nonlinear multiagent systems (MASs) to enhance the security and reliability against denial-of-service (DoS) attacks and actuator faults. With the framework of cooperative output regulation, the developed algorithm consists of designing a distributed resilient observer and a decentralized fault-tolerant controller. Specifically, by using the data-driven method, an online resilient learning algorithm is first presented to learn the unknown exosystem matrix in the presence of DoS attacks. Then, a distributed resilient observer is proposed working against DoS attacks. In addition, based on the developed observer, a decentralized adaptive fault-tolerant controller is designed to compensate for actuator faults. Moreover, the convergence of error systems is shown by using the Lyapunov stability theory. The effectiveness of our result is examined by a simulation example.

Nonlinear Cooperative Output Regulation with Input Delay Compensation

Nonlinear Cooperative Output Regulation with Input Delay Compensation

Cooperative Output Regulation for Continuous-Time Linear Periodic Systems

Cooperative Output Regulation for Continuous-Time Linear Periodic Systems

Adaptive Cooperative Output Regulation for Multiple Flexible Manipulators

Adaptive Cooperative Output Regulation for Multiple Flexible Manipulators

Refined Algorithms for Adaptive Optimal Output Regulation and Adaptive Optimal Cooperative Output Regulation Problems

Refined Algorithms for Adaptive Optimal Output Regulation and Adaptive Optimal Cooperative Output Regulation Problems

Distributed Event-Triggered Cooperative Output Regulation for Multiagent Systems

Distributed Event-Triggered Cooperative Output Regulation for Multiagent Systems

Cooperative Output Regulation of MASs With a Novel Parameter Convergence Condition and Prescribed-Time Event-Triggered Observers and Its Application to Robot Formation

Cooperative Output Regulation of MASs With a Novel Parameter Convergence Condition and Prescribed-Time Event-Triggered Observers and Its Application to Robot Formation

Data-Driven Cooperative Output Regulation of Linear Discrete-Time Multiagent Systems With Unknown Dynamics

Data-Driven Cooperative Output Regulation of Linear Discrete-Time Multiagent Systems With Unknown Dynamics

Cooperative Output Regulation for a Class of Switched Linear Multi-Agent Systems With Intermittent Measurements

Cooperative Output Regulation for a Class of Switched Linear Multi-Agent Systems With Intermittent Measurements

Cooperative robust output regulation for a class of nonlinear multi-agent systems over jointly connected switching networks

In this paper, we consider the cooperative robust output regulation problem for a class of nonlinear multi-agent systems over jointly connected switching networks. First, by attaching each subsystem with an input driven filter, we obtain an extended system. Second, by integrating the distributed observer approach and the distributed internal model approach, we convert the cooperative output regulation problem of the original system into a distributed robust stabilisation problem of an augmented error system which is also a multi-agent system. Finally, we solve the original problem by stabilising the augmented error system via a distributed output feedback control law.

Adaptive fuzzy fault‐tolerant control for cooperative output regulation with unknown nonlinear disturbances and actuator faults

AbstractThe cooperative output regulation problem with actuator faults and unknown nonlinear disturbances is a challenging research area in multi‐agent systems. This paper proposes an adaptive fuzzy fault‐tolerant controller to address this problem by employing a fuzzy logic system for approximating the unknown nonlinear disturbances. The internal model principle is utilized to transform the cooperative output regulation problem into a stability problem of an auxiliary system, with the aim of compensating for actuator failures in the system. By incorporating fuzzy logic system, the adaptive controller is able to approximate and compensate for the unknown nonlinear disturbances. Extensive simulations are conducted to validate the robustness and performance of the proposed method. The adaptive controller effectively handles actuator faults and achieves output regulation with unknown nonlinear disturbances.

The Binary Distributed Observer Approach to the Cooperative Output Regulation of Linear Multiagent Systems

In this note, the cooperative output regulation problem of general heterogeneous linear multi-agent systems with binary constraints is studied. To speed up the convergence rate, the binary distributed observer is proposed only utilizing sign of the relative state instead of using full relative information. Under some mild conditions, the binary distributed observer can estimate the state of the leader system exponentially in finite time sense. The leader system can generate various reference signals such as step functions, sinusoidal functions or their combinations. Furthermore, both state and output feedback control protocols are synthesized to solve the problem. An illustrative example is presented to support the feasibility of the proposed framework.

Data-Driven Practical Cooperative Output Regulation Under Actuator Faults and DoS Attacks.

This article addresses the resilient practical cooperative output regulation problem (RPCORP) for multiagent systems subjected to both denial-of-service (DoS) attacks and actuator faults. Fundamentally different from the existing solutions to RPCORPs, the system parameters considered in this article are unknown to each agent, and a novel data-driven control approach is introduced to handle such an issue. The solution starts with developing resilient distributed observers for each follower in the presence of DoS attacks. Then, a resilient communication mechanism and a time-varying sampling period are introduced to, respectively, ensure the neighbor state is available as soon as attacks disappear and to avoid targeted attacks launched by intelligent attackers. Furthermore, a model-based fault-tolerant and resilient controller is designed based on the Lyapunov approach and the output regulation theory. In order to remove the reliance on system parameters, we leverage a new data-driven algorithm to learn controller parameters via the collected data. Rigorous analysis shows that the closed-loop system can resiliently achieve practical cooperative output regulation. Finally, a simulation example is given to illustrate the effectiveness of the achieved results.

Robust cooperative output regulation for heterogeneous nonlinear multi-agent systems with an unknown exosystem subject to jointly connected switching networks

This paper investigates the robust cooperative output regulation problem for heterogeneous lower triangular nonlinear multi-agent systems with an unknown exosystem over jointly connected switching networks. The problem has been studied for the exactly known exosystem over switching networks. However, the existing result for the unknown exosystem is still limited to the static networks. To ensure that all followers acquire the reference trajectory generated by the unknown exosystem through the jointly connected switching networks, by combining a set of auxiliary filtering variables and fixed-time stability theory, an adaptive distributed observer is designed. On the basis of the adaptive distributed observer and the distributed internal model approach, we propose a distributed controller under several standard assumptions to solve the problem. Compared with the similar work subject to the static networks, the controller in this paper is applicable to the more general communication network while weakening the assumptions of the controlled system.