ANALYSIS OF FULLY COMPLIANT STRAIGHT LINE MECHANISM BY PSEUDO RIGID BODY MODEL

Abstract

A compliant mechanism can be defined as flexible structure, which uses elastic deformation to achieve force and motion transmission. These mechanisms are different from the classic linkage mechanisms with regard to the fact that they rely on elastic deformation for functionality. Hence any analysis of compliant mechanism requires a study of mechanics of deformable bodies, in addition to kinematics. Because of the same very reason, analysis and synthesis of compliant mechanisms has been the subject of significant study in the research community, which led to a number of design approaches for developing compliant mechanisms. Pseudo Rigid Body Model is one of the approaches. In this work, modeling and analysis of compliant straight line mechanism, based on Roberts approximate straight line mechanism, is explored. The Pseudo Rigid Body Model is used to model the compliant mechanism. Its motion and force-displacement relationship are predicted by Pseudo Rigid Body Model and finally, a commercial finite element code (ANSYS) capable of nonlinear analysis is used to model the mechanism with its flexible configuration. The theoretical results based on PRBM are compared with FEA results of compliant model, which suggest that PRBM reduces the complexity of analysis and is a desirable method for approximating an initial design phase of compliant mechanism.