Research On Obstacle Avoidance Path And Trajectory Planning Of 6R Industrial Robot

With the rapid development of modern factories,six-degree-of-freedom handling robots have been widely used in automated production lines.Moreover,the working environment of robots is becoming more and more complex,and the requirements for handling operations are constantly increasing,which makes the research on obstacle avoidance path planning and trajectory planning of robots of great significance.In this paper,six degrees of freedom handling robot is taken as the research object,and obstacle avoidance path planning,trajectory planning and time-energy-impact multiobjective trajectory optimization are studied.The main research contents include the following aspects:The kinematics of the robot is studied.According to the structural parameters of FANUC 200 ID 4S robot,the linkage coordinate system is established by improved DH parameter method,and the effective mathematical model is obtained.The forward and inverse kinematics equations of the robot were analyzed and solved.MATLAB software was used to establish the robot model,and the accuracy of the forward and inverse solutions of the robot was verified by simulation.Aiming at the obstacle avoidance problem of the manipulator,the spherical envelope box is selected to simplify the obstacle,and the cylindrical envelope box is selected to simplify the robot.To improve the RRT*-Connect algorithm,the variable probability ellipse sampling constraint is proposed,and dynamic step expansion is added to speed up path search,and the path length is shortened by node deletion strategy.Several scenes were set in MATLAB to verify the effectiveness of the algorithm,and a three-dimensional simplified model was established to simulate the robot handling environment.The improved RRT*-Connect algorithm was applied to the obstacle avoidance path planning of the robot,and the collision free path of the robot was obtained through the simulation.The trajectory planning was carried out in the joint space of the robot,the interpolation methods of polynomial and B-spline curve were analyzed and compared,and the optimal B-spline curve of fifth order was selected.The path nodes obtained in the obstacle avoidance path planning were extracted,and the path nodes were transformed into the rotation angles of each joint by the inverse kinematics of the robot.According to the rotation angles,the trajectory planning was carried out by using the B-spline curve of 5 degrees.The application of the third generation non-dominated sorting genetic algorithm(NSGA-Ⅲ)in multi-objective trajectory optimization of robots is studied.The NSGA-Ⅲ algorithm was used to optimize the trajectory planned by B-spline curves for 5 times,and the optimal frontier solution set was obtained.Compared with the optimal solution set obtained by NSGA-Ⅱ,it is proved that the solution set obtained by NSGA-Ⅲ is better and has better diversity.A normalized weighted objective function is constructed to obtain the multi-objective optimal trajectory.Compared with the trajectory before optimization,the running time,energy consumption and impact are reduced by 24.42%,18.7% and 29.7%,which proves the effectiveness of NSGA-Ⅲ algorithm in the multi-objective trajectory optimization of robots.The virtual prototype of the robot is built in ADAMS software.Then,the angular change sequence values obtained by simulation in MATLAB software are imported into ADAMS software for simulation experiment.The curve of Angle,angular velocity,angular acceleration and angular acceleration of each joint is obtained,which is basically consistent with the curve obtained by multi-objective optimal trajectory planning,and the end path of the robot will not collide with obstacles.The results of multi-objective optimal trajectory planning are verified.