Molecular forces in electromechanical integrated electrostatic harmonic actuator

Lizhong Xu,Xufei Shi

doi:10.1063/1.5009740

Abstract

Authors invent an electromechanical integrated electrostatic harmonic actuator. It is more favorable for miniaturization of the electromechanical devices. As the dimensions of the actuator decreases, the effects of the Casimir and van der Waals forces become obvious. Here, effects of the molecular forces on the operating behavior of the actuator are investigated theoretically investigated by a parametric study. The equations of the radial displacements of the flexible ring and the output torque for the actuator are deduced for three different situations: only considering electrostatic force, considering electrostatic and van der Waals forces, and considering electrostatic and the Casimir forces. The effects of van der Waals or the Casimir force on the radial displacements of the flexible ring and the output torque for the actuator are analyzed. Results show that van der Waals or the Casimir forces has obvious effects on the output torque of the actuator for small structure dimension. The results are useful in theory and technique studies on further miniaturization of the actuator.

Highlights

Micro-electromechanical system (MEMS) can be used in electronic assembly, micro spacecraft and military equipment.[1,2,3]Authors invented an electromechanical integrated electrostatic harmonic actuator.[4]
As soon as these segments electrodes are applied to voltage sequentially, a rotational electric field will be produced between flexible ring and stator
When the electrostatic force and van der Waals or the casimir forces are considered simultaneously, the voltage required for the same radial displacement decreases with increasing the radius of the flexible ring obviously

Summary

INTRODUCTION

Micro-electromechanical system (MEMS) can be used in electronic assembly, micro spacecraft and military equipment.[1,2,3]. Authors invented an electromechanical integrated electrostatic harmonic actuator.[4] The actuator mainly consists of flexible ring and outer ring stator (see Fig. 1). To increase output torque of the actuator, the clearance between the stator and flexible ring should be decreased to increase the electrostatic force. The three situations are: (i) only considering electrostatic force; (ii) considering electrostatic and van der Waals forces simultaneously; (iii) considering electrostatic force and the Casimir force simultaneously Using these equations, the effects of the van der Waals force or the Casimir force on the radial displacements of the flexible ring and the output torque of the actuator are investigated. Results show: van der Waals force or the Casimir force has obvious effects on the output torque of the actuator with small dimension. The results are useful in theory and technique studies on further miniaturization of the actuator (overall dimensions get to micro meter scales)

DISPLACEMENT OF THE FLEXIBLE RING

DRIVING TORQUE

RESULTS AND DISCUSSIONS

CONCLUSIONS