Optical flow-based closed-loop control of a multi-degree-of-freedom clamping-type ultrasonic motor.

Abstract

Rotor speed and position detection are integral parts of the closed-loop control system for multi-degree-of-freedom (multi-DOF) ultrasonic motors. The non-contact speed detection method is important for the high-precision control of the spherical rotor. This paper proposes a closed-loop control method based on an optical flow sensor for the velocity-position control of a multi-DOF clamping-type ultrasonic motor. The optical flow information is analyzed using the conical L-K optical flow algorithm to obtain the rotor speed and position. An incremental PID control method is used to perform dual closed-loop positioning control of the motor regarding speed and position. An experimental platform for the optical flow sensor is designed, and the method's feasibility is verified experimentally.