Robust adaptive dynamic surface control for linear time-varying systems

In this paper, robust output-feedback tracking control is considered for a class of linear time-varying plants whose time-varying parameters are unknown bounded with bounded derivatives and output is affected by unknown bounded additive disturbances. Using adaptive dynamic surface control technique, the proposed scheme possesses the following advantages: (1) the design procedure is simple and the control law is easy to be implemented, and (2) by introducing an initialization technique, together with adjusting some design parameters, the L-infinity performance of system tracking error can be guaranteed regardless of the time variation. It is proved that with the proposed scheme, all the closed-loop signals are semi-globally uniformly ultimately bounded. Simulation results are presented to demonstrate the effectiveness of the proposed scheme. Copyright (C) 2013 John Wiley & Sons, Ltd.