Degree of freedom of planar compliant mechanisms

A compliant mechanism is a mechanical device which uses the elastic deformation of its flexible elements to transfer motion, force, or energy. The use of flexible members always makes it difficult to distinguish joints from links, which causes that the concept of degree of freedom for compliant mechanisms is different from that of rigid-body mechanisms. Based on summarizing the characteristics of compliant mechanisms, the principles for determining their degree of freedom are analyzed. For the purpose of accurately describing the degree of freedom of a compliant mechanism, two concepts called rigid degree of freedom and compliant degree of freedom are introduced. Relevant corollaries are also presented. Through discussion of the modeling approach of several typical flexible elements based on the pseudo-rigid-body model and analysis of various compliant mechanism designs, an effective method for determining the degree of freedom of compliant mechanisms is given.