Stiffness analysis of two compliant pivots used in series elastic actuators

A compliant pivot used in series elastic actuators (SEAs) can be of great practical use for saving structure space. The analysis of load-deflection behavior for such pivots can provide an analytical mechanical design method. In this paper, two pivots are proposed for the corresponding implementation. Based on the Awtar accurate approximations, the two annulus compliant pivots are further simplified to linear stiffness behavior for the SEAs applications. Specifically, an annulus compliant pivot based on parallel leaf-springs is firstly analyzed. After that, we focus on a special kind of annulus compliant pivot whose degree of constraint (DOC) was released. Finally, the accuracy characteristics of the models are identified by comparing with the results obtained by nonlinear finite element analysis.