Coupling dynamic modelling of a flexible manipulator driven by servo joint using experimental identification method

Abstract

In this paper, the coupling dynamic model of a flexible manipulator driven by servo joint is established using experimental identification method. The dynamic model of the servo joint is proposed, which consists of a direct current servo motor, a harmonic gear reducer and a servo controller. By fitting the experimental data for the forward and inverse rotation of the motor, the coulomb friction constant and viscosity friction coefficient are obtained. Then, two transform function models that represent the system coupling dynamics are proposed. The input and output variables for one model are the control voltage of the servo controller and the angular displacement of motor. And for the other model, the input and output are the control voltage of the servo controller and the strain output measured by the strain gauges. Using the Pseudo-random binary sequence (PRBS) as the input signal, both the driven model of the servo joint and the vibration model of the flexible manipulator are identified by experimental identification. Experimental results show that the two identified models are in good agreement with the dynamic response of the experimental setup, both for the PRBS and sinusoidal excitation signals. Accordingly, the coupling dynamic models of the proposed system are obtained.