Precise position control of a travelling wave ultrasonic motor

A precise position control of a travelling wave ultrasonic motor is achieved, avoiding the traditional drawbacks attributable to the non-linear torque generation: overshoot or slow response time. For that purpose, a behavior model control is proposed and presented. With this control law, a quick and precise response is obtained. In this article, we present a position control scheme of an inertial load. The guidelines to that control was a rotation of 90 ° in a response time of about 300 ms with a position error of 0.6 mrad, targeting a typical application for avionics. In the paper, a shinsei USR30 is used, but the method can be applied to other ultrasonic motors.