Research On The Control System And Obstacle Avoidance Path Planning Of 7-DOF Collaborative Robot

This paper takes the 7-DOF collaborative robot TB7-R3 as the research object,designs an open robot control system based on Ether CAT bus technology and Twin CAT3 software platform,and conducts research on related motion control and obstacle avoidance path planning algorithms.The main tasks completed are as follows:(1)The independently developed robot control system is based on the Ether CAT bus technology,using the Twin CAT3 software and a small industrial computer as the Ether CAT master station,and using each joint module as the Ether CAT slave station.This combines the powerful computing power of the PC platform with the PLC module in the Twin CAT3 software,making it a high-performance robot motion controller.Finally,in conjunction with the human-computer interaction interface,real-time control from system level motion planning to hardware level joint driving can be achieved.(2)The kinematics model of the robot was established by the standard D-H method,and the numerical solution of the inverse kinematics was calculated iteratively by the Newton-Raphson method,and the singular pose was avoided by the damped least square method.The dynamics model of the robot is established by Newton-Euler method,and the gravity term is extracted from it.Finally,MATLAB robot toolbox is used to simulate the kinematics and dynamics models respectively to verify their correctness.(3)Based on the discrete collision detection algorithm and bounding box algorithm,a collision detection algorithm based on model simplification is proposed;The traditional RRT algorithm is improved by combining the bidirectional expansion strategy of Bi RRT algorithm and the progressive optimization strategy of RRT *algorithm,and the idea of gravitational field in the artificial potential field method is introduced to guide the random tree to grow towards the target point,thus further reducing the randomness of path expansion and improving the efficiency of path planning;Finally,a second-order B-spline interpolation algorithm and the removal of redundant nodes are used to smooth the path,thereby improving the quality of path planning.(4)Based on the self-designed open robot control system,Cartesian space trajectory planning experiments,drag teaching experiments and obstacle avoidance path planning experiments are carried out to verify the designed control system and related control algorithms.