Research On Manipulator Compliance Control Technology Oriented To Assembly Scene

The manufacturing industry is the foundation of the national economy,and robotics is an important force to promote the optimization and upgrading of the manufacturing industry.In the field of robotic automated assembly,industrial robots can replace humans in repetitive and high-frequency labor.At present,robotic arm assembly operations mainly rely on manual teaching.In tasks that require contact with the environment,it is highly dependent on the degree of description of the environment by the teaching trajectory.A small workpiece positioning error may cause the assembly task to fail.Since the existing position control cannot solve the contradiction between the high stiffness of the robot and the high stiffness of the environment,the research on the compliance control of the manipulator becomes particularly important.This paper takes the six-degree-of-freedom universal manipulator as the research object,and conducts research on the compliance control of shaft hole assembly in the assembly scene.The main research contents are as follows:(1)Establish the kinematics and dynamics model of the robotic arm.First,the screw theory is used to simplify the kinematics modeling process of the manipulator;secondly,in order to increase the efficiency of solving the inverse kinematics of the manipulator,the Paden-Kahan sub-problem is used to solve the inverse kinematics of the manipulator.Validity and accuracy;finally,a Newton-Euler dynamic equation based on the screw theory is given,which avoids a large number of calculations in the Lagrange method.(2)Analyze the trajectory planning and assembly scene in the compliance control problem of the robotic arm.First,the assembly trajectory planning and simulation were completed using the robotic arm kinematics model;secondly,in order to clarify the purpose of the compliant assembly,the assembly model of the shaft hole in the assembly scene was analyzed from the assembly stage and the assembly contact force situation,and a method was proposed.The compliant assembly control strategy improves the success rate of peg-in-hole assembly in the assembly scene.(3)Research on the compliance control method of the manipulator,and propose a compliance control method oriented to the assembly scene.First,analyze the torquebased impedance control and the position-based impedance control respectively;secondly,by building the MATLAB/Simulink model to identify the impedance parameters,the role of impedance parameters in compliance control and the influence of environmental parameters on impedance control are analyzed.;Thirdly,because traditional impedance control is sensitive to environmental parameters,an adaptive impedance controller is designed to track the assembly contact force;finally,the adaptive impedance control may cause excessive system overshoot due to changes in environmental parameters.A kind of adaptive impedance control with adjustment items is developed to increase the adaptability of impedance control to the environment.(4)Perform simulation verification on the proposed method.Coppelia Sim robot dynamics simulation software was used to build an assembly experiment platform.According to the proposed compliance assembly strategy and the adaptive impedance control method with adjustment items,simulation analysis was carried out from two aspects: trajectory tracking control and assembly compliance force tracking control.The effectiveness of the compliance control method for assembly scenes.In summary,this article studies the compliance control technology in assembly scenarios,discusses assembly trajectories,assembly strategies,and impedance control methods in depth,designs an adaptive impedance controller,and proposes a selfadjustment option.The impedance control method is adapted to improve the ability of force tracking in the assembly stage,and the effectiveness of adaptive impedance control with adjustment items for assembly force tracking in assembly scenarios is verified through the simulation platform.