An Unconventional Inchworm Actuator Based on PZT/ERFs Control Technology.

Yanyan Zhang,Tengfei Wang,Guojun Liu,Chunxiu Tang,Xuhao Yang,Jianfang Liu,Jianqiao Li

doi:10.1155/2016/2804543

Abstract

An unconventional inchworm actuator for precision positioning based on piezoelectric (PZT) actuation and electrorheological fluids (ERFs) control technology is presented. The actuator consists of actuation unit (PZT stack pump), fluid control unit (ERFs valve), and execution unit (hydraulic actuator). In view of smaller deformation of PZT stack, a new structure is designed for actuation unit, which integrates the advantages of two modes (namely, diaphragm type and piston type) of the volume changing of pump chamber. In order to improve the static shear yield strength of ERFs, a composite ERFs valve is designed, which adopts the series-parallel plate compound structure. The prototype of the inchworm actuator has been designed and manufactured in the lab. Systematic test results indicate that the displacement resolution of the unconventional inchworm actuator reaches 0.038 μm, and the maximum driving force and velocity are 42 N, 14.8 mm/s, respectively. The optimal working frequency for the maximum driving velocity is 120 Hz. The complete research and development processes further confirm the feasibility of developing a new type of inchworm actuator with high performance based on PZT actuation and ERFs control technology, which provides a reference for the future development of a new type of actuator.

Highlights

Precision positioning actuators have been widely researched for applications in various fields such as optics, microrobotics, memory storage, medicine, space, and military [1,2,3]
Thermal actuators are found to be more suitable for the fields requiring large force and large displacement under low voltage, but they have slow response
electrorheological fluids (ERFs) valve is in open state, and ERFs will flow from the inlet through the middle channels and holes and outflow from the outlet

Summary

Introduction

Precision positioning actuators have been widely researched for applications in various fields such as optics, microrobotics, memory storage, medicine, space, and military [1,2,3]. The electrostatic actuator is typically composed of two electrodes separated by a small gap Though it has fast response and low power consumption, the sharp nonlinearity of the gapforce relationship limits it to small displacements and makes it not suitable for the applications where displacements are larger than the scale of millimeter. As for the piezoelectric actuators actuated especially by PZT stack materials, they can generate large force, extremely precise displacements, and can have low power consumption and fast response. These characteristics described above make piezoelectric actuation one of the most promising options for developing the advanced precision positioning actuators

Methods

Discussion

Conclusion