Dynamic modeling and verification of a 4DOFhandling robot with closedloop kinematic chains
                                                   ZHANG Jin1, YUN Chao1, GUO Juan2
(1.School of Mechanical Engineering & Automation, Beihang University, Beijing 100083, China;2.School of Mechanical Engineering, North China University of Science and Technology, Tangshan 063009, China)
Abstract: Aiming at the problems of the heavyduty robot at high speed, such as the saturation of the joint drive motors, the strong nonlinearity of the joint torque characteristics, the strong coupling between different joint torques, the more significant phenomena of positioning residual vibration and trajectory tracking instability, the robot dynamics is necessary to effectively solve the above problems was studied. The DH method was used to analyze the kinematics of a 4DOF heavyduty handling robot with closedloop kinematic chains. The skew symmetric matrix method was presented to avoid the repeated operations of vector cross product and closedloop kinematics chain geometric constraints, and thus the derivation of differential kinematics equations was simplified. The analytical formula of the dynamics model was derived by Lagrange method based on the energy of the robot system. The correctness of the dynamic model was verified by Matlab/Simulink simulation of PID position control. The results indicate that the dynamic model can correctly reflect the dynamic characteristics of the handling robot, and provide reference curves for the next experimental verification of the dynamics model correctness, and the analytical formula of the model also provides a mathematical basis for the modelbased robot controller design.
Key words: dynamics modeling; simulation verification; skew symmetric matrix method; PID position control; closedloop kinematic chain; handling robot