An efficient performance evaluation method of the traveling wave rotary ultrasonic motor's flexible rotor.

For a traveling wave rotary ultrasonic motor, matching the stator with a proper flexible rotor can be challenging because of the actual contact mechanism's complexity. Due to the lack of effective evaluation and prediction means in the rotor design process, the prototype test is usually needed to truly measure how well it performs, leading to high cost and long design cycle. In order to solve this problem, an efficient performance evaluation method of the flexible rotor based on equivalent contact pressure is proposed.

Research on Fast and Precise Positioning Strategy of an Ultrasonic Motor Based on the Ultrasonic Friction Reduction Theory.

To address the problems of the large positioning error and long positioning time of the traditional positioning strategy, namely, the two-phase simultaneous power-off method (TPSPM), a new positioning strategy, called the first single-phase then two-phase power-off method (FSPTTPPM), based on the ultrasonic friction reduction theory, has been proposed in this work. This method realizes zero sliding displacement between the friction material and the stator during the torsional oscillation of the shaft by controlling the driving circle frequency and the duration of the single-phase power-off period, which reduces the deviation of the displacement reservation value. In order to verify the correctness of the driving mechanism, a test platform has been built, and two positioning strategies have been used for experimental verification.

Position control method for ultrasonic motors based on beat traveling wave theory.

Focusing on the application demand of ultrasonic motors in the field of space laser communication, a position control method is proposed in this study. Unlike other existing localization methods, this method is based on beat traveling wave theory, which possesses a particular performance in ultrasonic motors. In order to make the speed predictably drop to zero, the frequency difference of the two-phase drive signals is changed during normal operation.