The Research Of Time-optimal Trajectory Planning Of Industrial Robot Based On Some Given Path Points

With the gradual improvement of the intelligence level in the field of mechanical manufacturing,people's demand in robotic arms is not only limited in that certain tasks can be accomplished,but also in that the work efficiency is maximized and the work cost is reduced as much as possible on the basis that the tasks can be completed.Therefore,the research on the motion time,energy,precision and impact of the robot arm has become the focus of research in the field of robotics.This thesis mainly research the method of trajectory planning and the optimization method with the shortest time.The main contributions of the thesis are summarized as the following three aspects.(1)In the thesis,the PUMA560 robotic arm is researched as the target object and the D-H coordinate system is established on the basis of relevant parameters,and provide the spatial coordinate support for the establishment of the mathematical model of the robot arm.According to the D-H coordinate system,the kinematics equation of the manipulator is established,and the positive and inverse solutions are solved by establishing the kinematics equation,which supports the integrity of the algorithm described in the follow.(2)The application of the cubic B-spline curve in robot arm trajectory planning is studied in depth,and the real-time generation of robot arm joint trajectory is realized by using the improved cubic B-spline curve.The three-dimensional model of the manipulator is established in MATLAB,the motion trajectory of each joint is planned,and then the joint trajectory simulation in the joint space is complete.It is can be seen from the displacement,velocity and acceleration curves,which are obtained from the simulation,of each joint that the displacement,velocity and acceleration of the joint trajectory can be kept continuous in the improved cubic B-spline curve planning.In addition,the displacement and velocity curves are smooth and continuous in the improved cubic B-spline curve planning,and there is rarely no conflict in the acceleration curve.This is because that the fitted joint trajectory in the improved cubic B-spline curve has passed through the intermediate joint point at every point.The accuracy of the trajectory of the robot arm have been improved by all of these,and the mechanical arm task with relatively high processing precision is guaranteed.(3)In order to improve the working efficiency of the manipulator,the thesis used genetic algorithm to optimize the joint trajectory.By improving the genetic operator and process of the traditional genetic algorithm,the global search ability of the algorithm is guaranteed and the convergence speed of the algorithm is improved.Under the constraint of kinematics parameters,the improved cubic B-spline curve was used to optimize the joint trajectory,which eventually reduced the trajectory planning time from 20 s to 13.51 s,and the optimal efficiency reached 32.5 %,effectively improving the working efficiency of the robot arm.