New inverter-fed power ultrasonic motor for speed tracking servo application and its feasible evaluations

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