Abstract:

The output rotational speed of the servo drive system fluctuates due to the influence of environmental disturbances and the flexibility of the flexible manipulator with variable length during the process of rotation. The phenomenon will exacerbate the vibration of the flexible manipulator and affect the motion accuracy of the flexible manipulator seriously. Therefore， a proportional?integral （PI） control strategy based on the disturbance observer is designed to suppress the rotational speed fluctuation of the servo drive system. Firstly， the dynamic model of the dual?flexible servo blrive system was established and the transmission characteristics of the dual?flexible servo drive system were analyzed by using the Lagrange’s theorem. Then the PI control strategy based on the disturbance observer was applied to the speed loop in the dual?flexible servo drive system. The low pass filter parameters of the disturbance observer were designed by robust stability analysis. Finally， numerical simulation analysis and control experiments were carried out. The results verify that the proposed control strategy can effectively reduce the rotational speed fluctuation of the flexible manipulator with variable length and improve the motion accuracy of the servo drive system.

Key words: servo drive system, rotational speed fluctuation, joint flexibility, control strategy, PI control