Motion control of linear synchronous motors based on disturbance observer

A simple and high-performance path tracking control method which requires an accurate acceleration controller is proposed. To realize the acceleration control, disturbance feedback is necessary. The disturbance observer estimates the disturbance from a current reference to the power converter and a position signal with simple computation. The poles of the observer are varied in accordance with the velocity of the motor for precise positioning. In experiments using a linear synchronous motor (a kind of direct drive motor), precise high-performance path tracking control was realized. The effectiveness of this method against inertia variation, thrust ripple, and gravitational force is shown.