Development of a Self-Moving Ultrasonic Actuator With High Carrying/Towing Capability Driven by Longitudinal Traveling Wave

A self-moving ultrasonic actuator (SUA) that operated by the longitudinal traveling wave and possessed high carrying/towing capability is developed in this article. The SUA is constructed by serially clamping two longitudinal transducers onto a rectangular-rod-shaped vibrating body, and its driving feet produce elliptical motions to achieve self-movement. Here, the clamped configuration and longitudinal vibration facilitate the realization of large driving force, and the bar shape brings simple structure and low weight. Initially, the SUA is designed with two developed models to not only enhance the driving force without excessively increasing the weight, but also enable the elliptical motion shapes to approach circular ones. Subsequently, an SUA prototype with the size of 315 × 32 × 30 mm is fabricated, and its vibration properties, self-moving characteristics, and carrying/towing capability are assessed. At ∼27.8-kHz frequency and 800-V voltage, the payload and towing force reached 6 kg and 24.5 N, respectively. Moreover, the SUA yielded the payload-to-weight ratio of 10.2 and the towing force density of 41.5 N/kg, exceeding the values of most conventional ones. This article validates the longitudinal TW's potential to enhance SUAs’ carrying/towing capability, and also provides a new approach to design powerful ultrasonic/piezoelectric actuators.