Disturbance rejection using SMC-based-equivalent-input-disturbance approach

This paper uses the sliding-mode control (SMC) to compensate for an estimation error caused by the filter in an equivalent-input-disturbance (EID) compensator. The application of the SMC brings another shortcoming: The chattering problem. To solve such a problem, this paper makes use the features of the EID approach and presents a method of designing a small switching gain based on the estimation error. Combining the SMC, the EID approach, and the switching-gain design law, this paper presents a new system configuration. The presented SMC-based-EID control system not only improves the disturbance-suppression performance of the EID approach but also solves the chattering problem in the SMC. A comparison shows the validity and superiority of our method. Furthermore, the robustness of the disturbance-rejection performance with respect to measurement noise is also shown by the example.