Optimal design of wave generator profile for harmonic gear drive using support function

Abstract The wave generator profile for harmonic drive was designed using a closed convex curve generated by the support function. An optimization model of the wave generator profile was established, and the objective function was defined to minimize the maximum circumferential stress of the flex spline assembled with the wave generator. Then the curvature difference of the flex spline neutral line and pure kinematic error were investigated considering different wave generator profiles. Finally, the finite element method was applied to establish the assembly model. The stress and deformation of the flex spline were analyzed, as well as the stress of the flexible bearing. Results show that the maximum circumferential stress of the flex spline with the proposed wave generator profile was significantly reduced compared to the harmonic gear with a traditional elliptic wave generator. The stress in the major axis region of the flex spline is distributed more evenly after assembly with the wave generator. And the maximum Von-Mise stress of the flexible bearing was obviously reduced, as well as the contact force for outer ring and rollers in the major axis region of the wave generator.