Design Framework for Motion Generation of Planar Four-Bar Linkage Considering Clearance Joints and Dynamics Performance

Xueao Liu,Chunjie Wang,Jianzhong Ding

doi:10.3390/machines10020136

Abstract

In this paper, we present a novel design framework to connect linkage synthesis with dynamics performance of the linkage. The aim of the design framework is to improve the dynamics performance of the mechanism through linkage design, instead of improving manufacturing accuracy or changing driving strategy. Specifically, the design framework is to complete motion generation of four-bar linkage, considering clearance joints and dynamics performance. The constraint model of motion generation and the dynamics model of four-bar linkage are established, respectively. The coordinates of four joints of four-bar linkage are divided into two parts, one of parts is the parameters to improve the dynamics performance of the linkage and is selected as the optimization variables. The other parts of joint coordinates is to satisfy the kinematics requirements and is obtained by solving constraint equations of motion generation. Through optimization calculation, we can obtain the optimal configuration of the four-bar linkage that achieves specified task positions with high motion accuracy and low wear extent of clearance joint. Finally, a numerical example is proposed to demonstrate the novel design framework.

Highlights

The task of linkage synthesis is to determine the link dimension to form the linkage that achieve the specified task positions
According to the past literature [1,2], linkage synthesis can be divided into three task specifications, namely, motion generation, function generation, and path generation
We present a novel design framework to synthesize the four-bar linkage for motion generation considering clearance joints and dynamics performance

Summary

Introduction

The task of linkage synthesis is to determine the link dimension to form the linkage that achieve the specified task positions. According to the past literature [1,2], linkage synthesis can be divided into three task specifications, namely, motion generation, function generation, and path generation. Analytical method is to derive the synthesis constraint equations and solve it to obtain the configuration of the linkage. McCarthy et al [1], Freudenstein [3], and Wampler et al [4] derived the constraint equations of four-bar linkages for motion generation, function generation, and path generation, respectively; see [5,6,7]. Plecnik et al derived the constraint equations of six-bar linkage for motion generation [8], function generation [9], and path generation [10]. The advantage of analytical method is that all configurations of the linkage can be obtained by solving the constraint equations. The optimization method is a useful tool for linkage synthesis

Methods

Results

Conclusion