Design of discrete integral variable structure control systems and application to a brushless DC motor control

Abstract

A discrete integral variable structure control (DIVSC) approach is presented to achieve accurate servo-tracking in the presence of load disturbance and plant parameter variations. Conditions are derived to ensure the existence of non-ideal sliding motion. This scheme also proves that the describing motion in the non-ideal sliding region will be close to the ideal sliding motion. Further, procedures are proposed for determining the control function, the coefficients of the switching plane and the integral control gain. The procedures can cause the resultant system to have the desired properties. A microcomputer-based brushless DC motor servo position control system using the DIVSC approach is illustrated. Simulation results are compared with the PI controller to demonstrate the potential of the controller. Experimental results present the practical capability of the proposed controller.