Topology-optimization based design of multi-degree-of-freedom compliant mechanisms (mechanisms with multiple pseudo-mobility)

Unlike conventional mechanisms, compliant mechanisms produce the desired deformations by exploiting elastic strain. The mobility of a conventional mechanism is the number of independent coordinates needed to define a configuration of the mechanism. The corresponding concept applicable to compliant mechanisms is the so-called pseudo-mobility defined as the number of scalar parameters needed to identify one single desired deformation of a compliant mechanism. In the case of compliant mechanisms with multiple pseudo-mobility, only synthesis approaches for relatively simple mechanisms exist so far, while systems for more complex tasks like shape adaptation are not covered. In addition, only a limited choice of transverse loads are considered in those approaches. In this paper, a novel optimization algorithm is presented that addresses these two shortcomings. This algorithm is based on a two-step iterative procedure in which the load-case dependency of the deformation is minimized and desired deformations are imposed. The algorithm is tested on mechanisms of different complexity. It could be demonstrated that the new procedure is well suited for the synthesis of different types of compliant mechanisms.