Screw-type actuator driven by piezoelectric transducers

Shunming Hua,Yinghou Lou,Zhiqiang Li,Yuming Meng,Xiaojun Wang

doi:10.1177/1687814014568487

Abstract

The significant features of screw transmission are effort-saving and self-locking. Based on this, a screw-rod-type actuator is proposed, which is driven by a nut swung spirally together with piezoelectric transducers. The actuator consists of three parts: a nut fastened to a hollow cylinder, a precise screw rod, and two orthogonal piezoelectric vibrators worked on d33 mode. The screw rod is forced to rotate and translate by traveling wave within the helical surface of nut, which is generated by two vibrators. First, the actuator’s running mechanism is preliminarily illustrated. Second, modal analysis and optimal design of the stator are performed through finite element method. Finally, the prototype actuator is manufactured and tested. The experimental results have proven that this driving manner is feasible, and the main characteristics are as follows: the stable working frequency is about at 9.5 kHz, and the maximum no-load speed and output force are approximately 61 r/min and 2.1 N, respectively, under 300 Vpp.

Highlights

In recent decades, many researchers have enduring interests in finding out the corresponding solutions to meet demands of precise positioning in micro and miniature devices.[1]
Erismis et al.[5] designed an inchworm actuator working in low voltage, which could provide large displacement and output force in in vivo biomedical applications
A linear piezoelectric actuator of screw type with double vibrators based on d33 mode is proposed, and the driving mechanism is preliminarily analyzed

Summary

Introduction

Many researchers have enduring interests in finding out the corresponding solutions to meet demands of precise positioning in micro and miniature devices.[1]. For the screw-type actuator working on bending mode, the dynamic equation can be expressed briefly by modal parameters as follows. The above equations (24)–(26) provide theoretical reference for rod-type piezoelectric actuators to carry out simulation analysis and structural optimization, which work on bending mode. The analysis results indicate that the amplitude of the point within nut’s internal surface is too small (approximately zero) to drive the screw rod efficiently, when the vibrator length is 26 mm. It shows that the modal frequency decreases with increasing cylinder length, but the maximum amplitude occurs at the condition the. On the basis of the above simulation, there are a total of three orders of bending vibration mode existing in the frequency range of 0–37 kHz, and their modal shapes are shown in Figure 7(a)–(c), respectively.

Experiment and discussion

Results and discussion