Structural Design And Performance Research Of 3-RRR Micro–platform Based On Flexure Hinges

With the development of ultra-precision equipment towards high speed and high precision,the flexure hinge without clearance and wear has been more and more applied to micro-operation robots,precision optical instruments,aerospace and industrial equipment and other occasions.But there are still many problems in the design process of flexure hinges: on the one hand,various flexure hinges proposed by scholars are independent of each other,and it is difficult to give consideration to both structure type selection and structure parameter design in the design process,which brings new challenges to designers.On the other hand,the traditional flexure hinge has symmetrical structure,which has large axial drift and parasitic movement,which limits the improvement of flexure hinge precision.In this paper,a new kind of generalized flexure hinge has been designed,namely,conic-chamfered V-shaped flexure hinge,which includes parabolic-chamfered V-shaped,elliptic-chamfered V-shaped,hyperbolic-chamfered V-shaped,parabolic,elliptic arc,hyperbolic and straight beam flexure hinges.The compliance and precision equations were derived,the finite element analysis and experimental research were carried out,and the results had good consistency which verified the correctness and effectiveness of the theoretical model.By choosing different design parameters,the integrated design of structure types and structural parameters of conic-chamfered V-shaped flexure hinges can be realized simultaneously.In order to improve the motion accuracy of flexure hinges,an asymmetric elliptic arc flexure hinge was designed,and the compliance and precision matrices were derived by the proposed finite beam matrix modeling method,in which θ was used as a variable.The finite element analysis and experimental research were carried out,and the result s had good consistency which verified the correctness and effectiveness of the theoretical model.Compared with the precision of two typical flexure hinges(straight circular hinges and elliptic hinges),the results showed that the asymmetric elliptic arc flexure hinges had higher motion precision,which proved its superiority in precision.Taking the typical 3-RRR flexure micro-platform as the research target,three kinds of 3-RRR flexure micro-platforms,namely straight circular,conic-chamfered V-shaped and asymmetric elliptic arc shaped,were established respectively.The theoretical model was deduced and the finite element analysis was carried out,and the results were in good agreement.By comparing with the straight circular 3-RRR flexure micro-platform,it was proved that the conic-chamfered V-shaped 3-RRR flexure micro-platform had greater compliances under the action of unit load.However,under the action of unit load in the same direction,the asymmetric elliptic arc 3-RRR flexure micro-platform had less parasitic movement than the straight circular 3-RRR flexure micro-platform,and the asymmetric elliptic arc flexure hinge of the 3-RRR flexure micro-platform has less axial drift than the straight circular one.