Output-feedback tracking control for a class of nonlinear non-minimum phase systems via dynamic surface control

In this paper, we investigate the output tracking control problem for a class of nonlinear non-minimum phase systems via output-feedback. The method of output redefinition is applied to let the stability of the internal dynamics which is originally unstable depend on that of redefined output, thus we only need to consider the new external dynamics rather than internal dynamics in the process of designing control law. To conquer the derivation explosion problem in traditional backstepping design, the dynamic surface control (DSC) method is firstly utilized to handle the problem of tracking control for the nonlinear non-minimum phase systems. The proposed output-feedback DSC controller drives the system output to track desired trajectory asymptotically, and simutanneously forces the unstable internal dynamics to track its corresponding causal and bounded ideal internal dynamics, which is computed via the stable system center method. The validity of the proposed controller is verified via a numerical simulation.