Design of Robust Tracking Controllers Using Sliding Mode Technique

A simple methodology of designing robust tracking controllers using sliding mode technique is proposed in this paper for a class of nonlinear dynamic systems. This control scheme contains a simple perturbation estimation process embedded in the controller, so that the robustness of system’s stability can be maintained without knowing the upper bound information of perturbation itself and the estimation error of it. The perturbation estimator can be implemented by using a simple high pass filter. The tracking accuracy of control can be adjusted through two stages. The first stage is done by refining the perturbation estimation process. The second stage is done by adjusting the parameter of controller. Chattering phenomenon will never occur under this control scheme. The comparison between the proposed control scheme and the traditional sliding mode control in the frequency domain is given. A numerical example and a practical experiment are demonstrated for showing the applicability of the proposed control scheme.