Adaptive cooperative tracking control for a class of nonlinear time-varying multi-agent systems

In this paper, an adaptive cooperative tracking control scheme is proposed for a class of high-order nonlinear time-varying multi-agent systems, where only the output of the leader is available for some followers. By introducing a bound estimation approach and a smooth function, the obstacle caused by unknown time-varying parameters is successfully circumvented without any restriction on their variation speed. With the aid of the dynamic surface control technique, simple distributed adaptive controllers are obtained and each follower needs only the first two states rather than the full states of its neighbor followers, which considerably reduces the computational and communication burden. It is shown that all tracking errors converge to a residual set which can be made arbitrarily small. Simulation results on robotic manipulators are presented to illustrate the effectiveness of the proposed scheme.