Rapid design approach for flexspline tooth profile of high-reliability intelligent harmonic drives

Abstract The harmonic drive is a core component of industrial robots, where accurately determining the flexspline tooth profile parameters is often challenging. Excessive meshing stress is a primary factor affecting its transmission accuracy and service life. To enhance system reliability, this paper introduces a rapid design and modification methodology for the flexspline tooth profile grounded in two-dimensional (2D) finite element analysis, aiming to reduce meshing stress and extend gear service life. The method begins by establishing a flexspline assembly deformation model, adopting a common-tangent double-circular-arc tooth profile, and designing the circular spline profile based on conjugate envelope theory. In technical implementation, a parametric 2D finite element model is initially developed to replicate the meshing interaction between the flexspline and the circular spline. The actual tooth profile line is extracted through numerical calculation, followed by interference checking and radial modification. Subsequently, the tooth profile parameters are refined using the sequential quadratic programming algorithm to ascertain the optimal configuration. The results indicate that the maximum meshing stress after optimization is reduced by 23.5%, and the theoretically calculated high-cycle fatigue life is increased by 392%. The entire approach can be realized via Python scripting and seamlessly interfaced with Abaqus, demonstrating good engineering applicability and iterative efficiency. It can provide effective technical support for the rapid design of high-reliability harmonic drives and intelligent manufacturing systems.