Equivalent-Input-Disturbance Approach—Analysis and Application to Disturbance Rejection in Dual-Stage Feed Drive Control System

This paper deals with the high-precision positioning control of a dual-stage feed drive. The design of the control system is based on the equivalent input-disturbance (EID) approach to improve the disturbance rejection performance. An analysis of the EID approach reveals the mechanism of disturbance rejection. The design procedure is illustrated by a numerical example. Simulation results show that the EID control system not only rejects disturbances, but also suppresses uncertainties and nonlinearities in the plant. Design and simulation results for the example are also employed to compare our method with the disturbance observer method, and to demonstrate the validity of our method.