Design of the compound compliant Scott-Russel mechanism with non-conventional optimization of flexure hinges

Compliant mechanisms gain some or all their mobility from the relative flexibility of their joints rather than from rigid-body joints only. Compliant mechanisms can provide many benefits in the solution of design problems: they have less wear, weight, noise, and backlash than their rigid-body counterparts. They can be manufactured from one piece of material, and therefore they are suitable to be applied in micromechanics. However, nonlinearities introduced by the large deflection of elastic segments further complicate the analysis of compliant mechanisms. This paper considers the isosceles slider–crank mechanism and its compliant counterpart mechanism, being developed based on the rigid–body mechanism. The design of the compound compliant slider-crank mechanism with circular flexure hinges notch, consisting of two single compliant slider-crank mechanisms has been shown in this paper. The guiding accuracy and mobility of the newly designed compliant mechanism have been analyzed. Additionally, by using undercut notch flexure hinges, a new analysis is given, which aims to show another factor that has an impact on the operation of compliant mechanisms. This factor is represented by the position of joints and its influence is shown through improving the accuracy of the coupler point rectilinear path of the Scott-Russel mechanism. Hence, it will be described that the position of these flexure hinges and their geometry is a vital issue for performing an approximately rectilinear path. Therefore, several designs are investigated through the finite elements method (FEM) simulation.