Research And Application Of Motion Control Technology For Seven Degrees Of Freedom Redundant Manipulator

In the increasingly complex practical application scenarios,the new operational tasks and task environments also put forward higher requirements for the performance of robots.Therefore,the research on redundant manipulators in the academic and industrial fields has gradually deepened.Similar to the human arm,seven-degree-of-freedom manipulator can use its redundancy characteristics to achieve performance indicators such as joint avoidance limit,singularity avoidance,obstacle avoidance and joint torque optimization while completing complex tasks.Thus,this paper focused on the research and application of motion control technologies of the seven-degree-of-freedom redundant manipulator and completed the verification on the actual robot arm.Based on the D-H parameters of the Walker redundant manipulator,the joint model of the manipulator was established.The forward kinematics of Walker redundant manipulator was studied on the basis of setting the upper and lower limits of joint motion,and the workspace of the redundant manipulator was calculated by Monte Carlo method.The analytical solution of inverse kinematics of redundant manipulator was solved by using parameterized arm angle,the derivation of the analytical solution of inverse kinematics was realized on the redundant manipulator with the elbow joint bias,and the accuracy of the algorithm was verified in the simulation environment.Firstly,the dynamic modeling of Walker redundant manipulator and the control scheme based on dynamic models were studied.The advantages and disadvantages of the classical dynamic modeling methods and their application scope were analyzed.The dynamic model of redundant manipulator was established by Newton-Euler equation based on screw theory.On this basis,the theory of gravity compensation and impedance control based on dynamic model was studied.Secondly,the whole process of dynamic parameter identification of Walker redundant manipulator was studied.Based on the dynamic model,the Coulomb-viscous friction term was introduced,and the minimum parameter set was further deduced by linearization.Then the excitation trajectory was designed in the basic form of the Fourier series,and the coefficients of the excitation trajectory were optimized with the objective of minimizing the condition number of the observation matrix,and the available joint trajectories were obtained.According to the collected data and theory,the minimum parameter set of the Walker redundant manipulator was obtained,and the accuracy of the minimum parameter set was verified by inverse dynamics calculation.Finally,the application of motion control technology was completed on Walker manipulator.In the drag teaching of torque-free sensor based on gravity compensation,according to the analysis of the feedback data and the actual control effect,the accuracy of joint torque value calculated in real time can meet the control requirements,and the accuracy of the previous dynamic model and control principle as well as the minimum set of parameters identified by dynamic model parameters was verified.In the impedance control of joint space and Cartesian space,according to the analysis of the feedback data and the actual control effect,the impedance control can meet the force compliance requirements of the manipulator during operation.