Estimation and modeling of the harmonic drive transmission in the Mitsubishi PA-10 robot arm

The purpose of this paper is to present our results in developing a dynamic model of the Mitsubishi PA-10 robot arm for the purpose of low velocity trajectory tracking using very low feedback gains. The novelty of this research is therefore the development of a systematic algorithm to extract the model parameters of a harmonic drive transmission in the robot arm to facilitate model-based control. We have chosen the elbow pitch joint (joint 4) of the PA-10 robot arm for estimation and modeling purposes. We have done several experiments to identify the various parameters of the harmonic drive system. We conclude with a sample trajectory tracking task whereby the feedback torque required to do trajectory tracking with and without the parameter identification of the HDT is significantly different.