Continuous variable structure system for tracking control of BLDDSM

The design of a continuous, accurate, and robust variable structure system with a disturbance observer is presented for tracking control of brushless direct drive servo motors(BLDDSM). The tracking problem with an arbitrary initial position of the desired trajectory is handled. With the proposed algorithm, not only the chattering and reaching phase problems are removed, but also the prescribed performance can be obtained by using the sliding dynamics. The usefulness of the proposed algorithm is demonstrated through the comparative simulations for a BLDDSM under load variations.