Analysis of Bridge-type Distributed-compliance Mechanism

Lei-Jie Lai,Xiao-Qia Yin,O.S Es-Said,C.A Huang

doi:10.1051/matecconf/201821301005

Lei-Jie Lai, Xiao-Qia Yin + Show 2 more

Open Access

https://doi.org/10.1051/matecconf/201821301005

Copy DOI

Abstract

This paper analyses a class of bridge-type distributed-compliance mechanism, which has better performances than traditional bridge-type mechanisms using notch flexure hinges. An analytical model for the displacement amplification ratio and input stiffness calculations of the bridge-type mechanism is established based on the stiffness matrix method. The finite element analysis results are then given to validate the correctness of the analytical model. The differences of the analytical results with respect to the finite element analysis results are less than 8%, which demonstrate the high accuracy of the analytical model. The influences of the geometric parameters on the amplification ratio and input stiffness of the mechanism are also investigated using the analytical model to provide theoretical guidelines for the practical design.

Highlights

The piezoelectric actuator (PZT) is widely adopted due to its advantages of ultra-high resolution, fast response, high stiffness, compact size and high push force [1]
The relative differences between the analytical results and finite element analysis (FEA) results of the three samples are all less than 8%, which indicates that the two results are in good agreement
The analytical model is established to analyze the influences of the geometric parameters on the displacement amplification ratio and input stiffness. l, b, t and θ are chosen as the designed geometric parameters of the mechanism

Summary

Introduction

The piezoelectric actuator (PZT) is widely adopted due to its advantages of ultra-high resolution, fast response, high stiffness, compact size and high push force [1]. Compared with the traditional lever-type mechanism, bridge-type flexure mechanism has the advantages of large amplification ratio, high resonant frequency and compact size, which becomes more and more popular. Lobontiu and Garcia formulated an analytical model for displacement and stiffness calculations of planar compliant mechanisms with singleaxis flexure hinges based on the Castigliano's second theorem [3]. Compared with the lumped-compliance mechanism, the distributed-compliance mechanism adopts four beam flexures to replace the notch flexure hinges and the rigid bodies, resulting in increased resonant frequency of the mechanism [5]. An analytical model for the predictions of theoretical displacement amplification ratio and input stiffness is derived using the stiffness matrix method and validated by FEA. The influences of geometric and material parameters on the performances of the mechanism including the displacement amplification ratio and input stiffness are well analyzed according to the analytical model

Analytical model

Influences of geometric parameters

Findings

Conclusions