Synthesis and Optimization of Compliant Mechanisms from a Rigid-Body Approach

Abstract

A systematic approach for compliant mechanism synthesis starting from the problem requirements s proposed. The proposed method uses as topological solution space several atlases of compliant mechanisms specialized from rigid kinematic chains. Although these atlases -with rigid and flexible links and joints- configure a subspace of the possible compliant mechanisms, they are very useful concepts from the functional point of view, and additionally, they are suited for the systematization of the design process. Graph Theory is used to solve the type synthesis stage while the rigid analytical synthesis combined with a process called rigid-body replacement synthesis is used to synthesize the flexible members. Several industrial test problems were solved using this method: a two-degree-of-freedom switch, a multiple deflector for nozzles of a turbine engine, and a bistable actuator for landing gear retraction. The latter test will be illustrated throughout this paper. The best concept for each problem is optimized using commercial software. Part of the methodology may be extended for dealing with compliant mechanisms with arbitrary topologies different from those arising from rigid-kinematic chains.