An analysis of the compliant mechanism models

This paper presents a focused examination of the current design formulations of compliant mechanisms posed as a topology optimization problem. With the use of a linear elasticity analysis, we examine the common formulations and analyze their nature of being ill-posed. We then analyze the role of the external springs added in the formulations and their consequences in the compliant mechanism optimization. It is shown that the use of an output spring tends to regularize the mathematical model, but it emulates at best a rigid-body linkage at the true optimum design. As a result, the topology optimization using the spring model generates point flexures in the resulting optimal mechanisms.