A Reference Shaping Filter Design Method for Discrete-Time Sliding Mode Control with Decoupled Disturbance Compensator to Inhibit Overshoot

The discrete-time sliding mode control (DSMC) is a highly utilized method in industrial systems, such as manufacturing systems, robot manipulators, and automation systems. The DSMC with decoupled disturbance compensator (DDC) method is one of the robust control methods with high tracking performance and fast responses. Based on error dynamics, a performance-shaping methodology for DSMC with DDC has also been developed to reduce tracking position errors in industrial servo systems. However, the input reference to the output transfer function of the DSMC has a transfer function zero, causing an unwanted overshoot and degrading the performance of the controller. Thus, this overshoot characteristic can be problematic in some systems that have stringent no-overshoot specifications. In this paper, a reference shaping filter design method is proposed that inhibits any overshoot in the response of the DSMC with DDC in a double-integrator system. The presented controller is applied to a linear motor system to illustrate the performance.