Prescribed-Time Cooperative Output Regulation of Nonlinear Multiagent Systems Under DoS Attacks

Nonlinear multi-agent systems (MASs) capitalize on cooperative output regulation strategies to achieve synchronized behaviors. However, the influence of unknown time-varying parameters complicates the control design, and denial-of-service (DoS) attacks present risks to the stability of the communication topology. To this end, a prescribed-time hierarchical control framework is proposed for MASs with time-varying parameters and DoS attacks. First, a distributed resilient observer with predefined time convergence is proposed to obtain the information of the exosystem signal. To obtain the exosystem state within a predefined time and guarantee the reference signal with the existence of high-order derivatives, a high-order signal generator based on the concept of high-order filters is established, with its dynamics driven by the observer state. Then, by viewing the output of the high-order signal generator observer as the reference signal and utilizing a prescribed-time adjustment function, a prescribed-time controller is designed for each agent to solve the reference-tracking problem in the back-stepping design framework. By introducing a smooth function with positive integrable time-varying properties, novel adaptive laws are developed and incorporated into the controller design, in which a new compensation mechanism is constructed to more effectively counteract the effects of unknown time-varying parameters. It is concluded by Lyapunov stability theorem that the proposed method can not only guarantee that all the closed-loop signals are globally bounded, but also ensure that the output regulation errors converge to zero within prescribed time. Finally, an example is employed to validate the correctness and good performance of the designed algorithm.