New speed tracking controlled direct-drive servo system using compact travelling-wave type ultrasonic motor

This paper describes the review of a travelling-wave type ultrasonic motor (T-USM) and a newly-proposed speed tracking controller of T-USM on the basis of computer software-based variable-gain adjustment strategy. Its speed characteristics which are effectively capable of improving speed ripple, speed regulation and speed tracking properties are feasibly demonstrated in experiments as compared with a previously-developed fuzzy-logic speed controller of a T-USM actuated servo system. It is proved that T-USM speed control scheme developed herein is practically acceptable for speed servo direct drive systems