Adaptive repetitive control for a class of nonlinear systems with unknown control direction
控制方向未知非线性系统的自适应重复控制

We present an adaptive repetitive control for a class of nonlinear systems with periodic nonparametric uncertainties and unknown control direction. This repetitive controller is designed with the aid of Nussbaum function; and the saturation mechanism adopted in the learning algorithm confines the estimated parameters to a pre-determined region. The proposed control method guarantees that all the signals in the closed-loop are bounded and the tracking error converges to zero as time approaches infinity. Numerical simulations are carried out to demonstrate the effectiveness of the presented control scheme.