Iterative learning control for nonlinear system based on sliding mode observer

A sliding mode observer based iterative learning control scheme for a kind of nonlinear system to track a trajectory with a finite time interval is presented. According to the nonlinear characters of the system, the states are estimated by a sliding mode observer, and the iterative learning control law is designed using the estimate signals. The method is not hypersensitive with the measurement error since without using the derivate of the tracking error signal in the control law. The convergence of the proposed control law is proved, and numerical simulation results show the validation of the control law.