Kinematics Analysis of Meshed Teeth Pairs of Harmonic Drive Gears Considering the Load Effect Using Computer Vision

This paper presents a vision-based kinematics analysis method to reveal the effects of the load torque on the kinematics characteristics of the meshed teeth pairs of the harmonic drive (HD). First, the meshing process of the HD under different loading conditions is measured by a dedicated experimental apparatus, and the positions of the output FS teeth in the meshing process are obtained by a position tracking algorithm. Next, an image-based mathematical model is established to calculate the kinematics parameters of the output FS teeth, and the accuracies of the calculated results are evaluated by uncertainty analysis. The results show that the driving speed has negligible effects on the variation tendencies of the kinematics parameters of the output FS tooth in the meshing process under no-load condition. Moreover, the stick-slip motion exists in the meshing process under ultra-low speed and loading conditions, and the critical speed of the stick-slip motion increases as the load torque increases. Furthermore, the average transmission ratio of the meshed teeth pair in the meshing process is constant, and it is nearly not affected by the load torque. Our method opens an avenue for the further studies on the mechanism of the stick-slip motion in the meshing process of the HD.