Abstract
A controller based on a variable structure comprises: a switching function calculation unit for receiving a position reference received from the outside of a motor and a plant to be controlled and a position feedback from the motor and plant, so as to calculate a switching function used for variable structure control; a variable structure high-order external disturbance estimation unit for estimating external disturbance applied to the motor and plant on the basis of the switching function, and outputting an estimated external disturbance signal; and a variable structure current command generation unit for generating a current command applied to the motor and plant, on the basis of the position reference, the position feedback from the motor and plant, the switching function, and the estimated external disturbance signal. Accordingly, the influence on a difference between a system model and an actual load model of an external disturbance compensator can be reduced.