Theoretical Analysis of Rotational Transmission Error of Strain Wave Gearing

Strain wave gearing which is a compact mechanical device producing high mechanical advantage and speed reduction, has been used to accurately position the arms and wrists of robots. In this paper, the cup type strain wave gearing is transformed to an equivalent engagement model, in which a lot of tooth pairs can engage at the same time. Tooth deformation of flexible spline in circumference which are caused by the coning of flexible spline and accumulative pitch errors of the circular spline and flexible spline are taken into account in the model. Based on the equilibrium of the static forces on the model, the rotational transmission errors of strain wave gearing are calculated and compared with the measured results.