Experimental development of an ultrasonic linear motor

Abstract

The authors investigate a novel ultrasonic motor which generates a stator trajectory in the form of a figure-of-eight by superimposing two resonant modes, with one double the frequency of the other. Topology optimization was used to design the stator structure. In contrast to traditional travelling wave ultrasonic motors, which require two modes to be driven 90° out of phase, only one amplifier is required to drive the proposed device. A prototype device was characterised experimentally and was used to drive a linear bearing at 14 mm/s reversibly and a force of 50 mN was developed by the motor.