On the Design Methodology of Flexure-Based Compliant Mechanisms by Utilizing Pseudo-Rigid-Body Models with 3-DOF Joints

This paper focuses on the complex design process of planar compliant mechanisms with flexure hinges. In the following a systematic methodology of the transition from lever mechanisms generated intuitively by the developer or non-intuitively by topology optimization to applicable compliant mechanism is presented. An extended pseudo-rigid-body model (PRBM) is used for the analysis and the modification of the lever mechanisms during the design process. Hereby, the flexure hinges are assumed as planar joints with 3 degrees of freedom (DOF) and the corresponding stiffness/compliance. Therefore, the planar deformation of the flexure hinges caused by the applied force and moments can be displayed. Based on this extended PRBM a subsequent optimization for the mechanism and the flexure hinges is applied to significantly reduce time and effort of the development process. Based on the presented development methodology a novel compliant mechanism with one DOF is created. Here, a maximum displacement of 635.8μm for an input displacement of 40μm can be achieved.