Frequency-Domain Design Method for Discrete-time Sliding Mode Control and Generalized Decoupled Disturbance Compensator with Industrial Servo Applications

Abstract A discrete-time sliding mode control (DSMC) with a decoupled disturbance compensator (DDC) is a nonlinear and robust control method, which is suitable for slowly-varying disturbances. To effectively compensate the disturbances, the gain of the DDC should be designed in a systematic way. This paper presents a frequency-domain design method of the DSMC with DDC in the presence of disturbance and time delay. In addition, a new generalized decoupled disturbance compensator (GDDC) is designed in the frequency domain, which improves the phase response as compared to the conventional DDC. Experimental results on an industrial servo system demonstrate the improved performance of the DSMC with GDDC method.