Using Singularities of Parallel Manipulators to Enhance the Rigid-body Replacement Design Method of Compliant Mechanisms

The rigid-body replacement method is often used when de-signing a compliant mechanism. The stiffness of the com-pliant mechanism, one of its main properties, is then highly dependent on the initial choice of a rigid-body architecture. In this paper, we propose to enhance the efficiency of the syn-thesis method by focusing on the architecture selection. This selection is done by considering the required mobilities and parallel manipulators in singularity to achieve them. Kine-matic singularities of parallel structures are indeed advan-tageously used to propose compliant mechanisms with inter-esting stiffness properties. The approach is first illustrated by an example, the design of a one degree of freedom compliant architecture. Then the method is used to design a medical device where a compliant mechanism with three degrees of freedom is needed. The interest of the approach is outlined after application of the method.