Adaptive dynamic surface control for a class of MIMO nonlinear time-varying systems

This paper is devoted to the adaptive output tracking control for a class of multi-input multi-output (MIMO) nonlinear time-varying systems. By fusing a bound estimation approach, a smooth function and a time-varying matrix factorization, the obstacle caused by unknown time-varying parameters is circumvented and an adaptive dynamic surface control scheme is proposed. The proposed scheme is free of the problem of explosion of complexity and needs only one updated parameter at each design step, which significantly reduces the computational burden. It is proved that all signals of the closed-loop system are semi-globally uniformly bounded and the tracking errors converge to a residue set which can be made arbitrarily small by properly choosing some design parameters. Simulation results are presented to illustrate the effectiveness of the proposed scheme.