Reliability analysis of harmonic drive with multiple failure modes based on improved calculation model of flexspline stress

The impact of the axial length of the flexspline on the overall structural reliability of harmonic drives is commonly underestimated in research. To address this issue, this study introduces an improved equation for accurately calculating flexspline stress. In assessing the reliability of harmonic drives, the study takes into account the interplay of flexspline strength failure, flexspline contact failure, and flexspline tooth wear failure, using the Copula function and the Monte Carlo method. Through numerical simulations, the study investigates the influence of flexspline length, revealing a growing impact as the length decreases. Furthermore, considering both flexspline length and multiple failure modes leads to an increased likelihood of failure as calculated. The proposed model significantly enhances the precision of reliability assessments for harmonic drives, thereby allowing for more accurate predictions regarding their operational lifespan.