Development of an ultrasonic linear motor with ultra-positioning capability and four driving feet

This paper presents a novel linear piezoelectric motor which is suitable for rapid ultra-precision positioning. The finite element analysis (FEA) was applied for optimal design and further analysis, then experiments were conducted to investigate its performance. By changing the input signal, the proposed motor was found capable of working in the fast driving mode as well as in the precision positioning mode. When working in the fast driving mode, the motor acts as an ultrasonic motor with maximum no-load speed up to 181.2 mm/s and maximum thrust of 1.7 N at 200 V_p-p. Also, when working in precision positioning mode, the motor can be regarded as a flexible hinge piezoelectric actuator with arbitrary motion in the range of 8 μm. The measurable minimum output displacement was found to be 0.08 μm, but theoretically, can be even smaller. More importantly, the motor can be quickly and accurately positioned in a large stroke.