Abstract: The joint physical parameters of robot change when the robot moves, which causes the change of dynamic characteristics of robot. It is very important to track and identify the joint physical parameters of robot in real time for controlling vibration of robot. An on-line identification method of frequencies and mode shapes of time-varying structure system is presented based on modern harmonic identification, and the force and displacement of joint of the robot are computed by harmonic propagation method, and dynamic stiffness and dynamic damping are computed based on displacement accord and force balance, finally the stiffness and the damping of joint of robot are presented. The cost of testing is saved because the method can predigest testing node. Experiment shows that the method has good tracking capacity and high computing precision.

Key words: Harmonic propagation, Joint parameter, Robot, System identification, Time-varying system