Coupling dynamic modelling and parameter identification of a flexible manipulator system with harmonic drive

This paper formulates a coupling dynamic model for a flexible manipulator system with harmonic drive using experimental identification method. Parameters of the driven model of the harmonic joint and parameters of coupling vibration model of the flexible manipulator are identified. Accordingly, coupling dynamic models of the proposed system are obtained. Coulomb friction of the joint is identified by step current excitation and uniform rotation experiments at a low speed. Then, the transfer function model of the harmonic joint is established and identified by a pseudorandom binary sequence excitation. And predicted outputs of the obtained model are in good agreement with the experimental setup. Relationships between strain of the flexible manipulator and coupling torque are presented by theoretical derivation. Based on the theoretical model, transfer function from the angular displacement of the servo motor to the coupling torque is identified. Experimental results show this identified model match well with the proposed structure, both in the time and frequency domain. As a result, coupling dynamic modelling of the flexible manipulator system with harmonic drive is accomplished.