Abstract: Harmonic drive systems are widely used in joints of space manipulators because of their low relative quality, compact structure and low costs. However, dynamic characteristics, including kinematic error, stiffness, and friction of harmonic drive systems, hinder the performance improvements of space manipulators, such as pointing accuracy and stability. To overcome this problem, scholars research the experiments, analyses and models on the dynamic characteristics of harmonic drive systems. This paper reviews studies about kinematic error, stiffness and friction. Some research topics are presented.

Key words: harmonic drive system, kinematic error, nonlinear stiffness, nonlinear friction, dynamic model