Sliding mode control with direct self-tuning for a class of nonlinear system with unknown uncertainties
未知不确定非线性系统的直接自校正滑模控制

Based on the combination of the direct adaptive control and the sliding-mode control, we present a new robust tracking controller for a class of nonlinear systems with unknown uncertainties. The controller treats the nonlinearity, the parametric uncertainties and the external disturbances as the system uncertainties. Without the boundaries and other information of the uncertainties, the controller and the self-tuning laws for the parameters are designed by using the Lyapunov stability theory. The closed-loop system is robust and asymptotically stable in the sense of the Lyapunov stability. The state trajectories can reach the sliding mode within finite time, eliminating the control input chattering thereafter. Simulation results are presented to verify the feasibility and correctness of the proposed control scheme.