Design and Experiment of a Large-Aperture Hollow Traveling Wave Ultrasonic Motor with Low Speed and High Torque

Abstract

To realize applications involving low speed and high torque in the high-performance actuator industry, especially in the aerospace field, we propose a novel 70H traveling wave rotary ultrasonic motor (TRUM) with an outer diameter of 70 mm and an aperture ratio of 53% (the ratio between the aperture and outer diameter). The power transmission mechanism between the stator and the rotor is analyzed, and a method for realizing low-speed–high-torque characteristics of TRUMs is proposed. ANSYS software is used to simulate the modal parameters of the stator, and the ratio β between the normal amplitude and the tangential vibration velocity of the stator is proposed. The larger the value of β, the lower the speed and the higher the torque. Furthermore, two prototype motors are fabricated, namely, 70HA and 70HB. Compared with 70HA, the maximum no-load speed of the improved 70HB (50 rpm) is decreased by 23.1% and the maximum stall torque (2.4 N∙m) is increased by 100%. Besides this, with a smaller mass of 210 g and a higher torque density of 11.43 N∙m/kg, 70HB has fundamentally different mechanical characteristics.

Fabrication and Characterization of a Microscale Piezoelectric Vibrator Based on Electrohydrodynamic Jet Printed PZT Thick Film

“…However, the bonding process of epoxy adhesive is very complex and causes the thermal depolarization of piezoelectric material to reduce the performance of the vibrator. Liu et al [ 4 ] and Lu et al [ 5 ] fabricated piezoelectric vibrators as drive sources for ultrasonic motors using the traditional method of bonding piezoelectric bulk and an elastic body with organic adhesives. In this regard, the bonding process of piezoelectric bulk vibrators requires complicated processes such as coating glue uniformly and aligning positions to paste the piezoelectric bulk.…”

A study on modeling of a piezoelectric motor

“…The algorithm reduces the time required in the process of identification. Many researchers considered mechanical characteristic of contact frictional layer and calculated displacement and speed of the rotor using [11]- [13]. In [14]- [16] dynamic contact problems between a rigid rotor and deformable stator were approximately solved.…”

Mechanical optimization of a novel hollow traveling wave rotary ultrasonic motor

“…Based on H-TRUMs, researchers presented a new way to understand the mechanical characteristics of an ultrasonic motor using finite element (FE) analysis in the 1990s (Krome and Wallaschek, 1996; Maeno et al, 1992), which aroused people’s research enthusiasm. Thereafter, with the lightweight structures getting more and more attention, a large number of H-TRUMs (Duan et al, 2009; Liu et al, 2019; Peng et al, 2015; Qu et al, 2006) have been proposed, which have achieved successful applications. However, on account of the limitation of traditional preloading method (preload is produced by the deformation of rotor and stator; Ueha et al, 1993), their working life will be reduced sharply due to the abrasion of friction material (Ishii et al, 1995, 1998; Wallaschek, 1998).…”