Research On Force Feedback Of Tele-operation Redundant Robot Based On Variable Gain

The “self-motion” of redundant slave-hand makes the tele-operation system with redundant robot has good flexibility, obstacle avoidance ability. The tele-operation system combined with redundant robot can improve the flexibility and efficiency of tele-operation system. So the research of the tele-operation system with redundant robot has important theoretical significance and practical application value.This paper developed under the national project named “Tele-operation multi-DOF electro-hydraulic servo parallel manipulator with accurate force feedback”(No. 50975118) and the research fund for the doctoral program of higher education named “the Bilateral Servo Control Strategy of tele-operation of electro-hydraulic underactuated redundant robot”(No. 20130061110009), and researched theories to improve the performance of force feedback of the tele-operation redundant robot bilateral servo control system.We take the four-DOF master-slave isomerism tele-operation redundant robot system as the controlled object, then the kinematics, dynamics characteristics of redundancy slave manipulator are analyzed. The workspace is calculated and the singular configuration is also analyzed. The mathematical models of the electro-hydraulic servo control system of the master-slave hand are established and the stability of the electro-hydraulic position servo system is analyzed. In view of the defects of Ziegler-Nichols method, the PD controller is designed by using the parameter space graphic method to improve the dynamic response characteristics of the electro hydraulic servo system.According to the force feedback effect is not sufficient and the impact on the operator’s problems, the variable gain position constraint space bilateral servo force feedback control strategy is put forward based on position constraint space control strategy. Finally, through the simulation experiment under the condition of no load, spring load and rigid load, the effectiveness of the proposed control strategy is verified. The simulation results show that the variable gain position constraint space bilateral servo force feedback control strategy can effectively improve the sensitivity of the force feedback and effectively reduce the force feedback to the operator. So that an operator can perceive the contact object softness and obtain better force feedback effect, and the force sense bilateral servo control of tele-operation redundant robot system is realized, which improves the transparency of the tele-operation system.