Research On Collision Avoidance Path Planning And Trajectory Optimization Algorithm Of Double Manipulator

With the popularization of industrial automation and the increase of intelligent demand,the performance requirements of industrial manipulator are more and more stringent.The robot's working efficiency,load capacity,and working space needs to be improved.The trajectory optimization of the manipulator is a very important technical means to improve its production efficiency.How to make the industrial manipulator take the least time to move along a given cartesian space path,and at the same time,it must be ensured that the manipulator is subject to kinematic constraints and nonlinear dynamic constraints of the manipulator during actual movement,which is still a question worth studying.Although the dual-manipulator coordination system has the advantages of strong load capacity and large working space,its coordination to avoid collisions is very difficult.Therefore,this subject has studied the path planning and trajectory optimization algorithms for the collision avoidance of dual manipulators.First,the kinematics model of the manipulator is created based on the modified D-H parameters.When analyzing the inverse kinematics,the geometric projection method and the Euler angle method are used successively.The solution method is to obtain the first three joint angles that determine its end position and the last three joint angles that determine its end posture.Then a group of inverse solutions of the manipulator are obtained.The method is simple and fast.According to the kinematics of a single manipulator,the loosely coordinated kinematics relationship of double manipulators is established.By using the Newton-Euler method and the Lagrange method respectively we analyzed the dynamics of the manipulator,and wrote a dynamic algorithm program.We verified the dynamic algorithm by using the dynamic algorithm program simulation experiments and we also compared the calculation efficiency and error of the two dynamic algorithms.Second,based on the RRT(rapidly exploring random tree)algorithm,we studied the collision avoidance path planning of the double manipulator.First of all,a collision detection algorithm suitable for the path planning of the collision avoidance path of the double manipulators is constructed through theestablishment of the collision model and the intersection test.The algorithm is used to judge the validity of the state during the path planning of the manipulator;then for the shortcomings of the basic RRT algorithm such as blind searching,not easy to converge,and too many turning points have been improved.The improved RRT algorithm has fast convergence speed and smooth path planning.The improved RRT algorithm is applied to double manipulators collision avoidance path planning.Third,the trajectory optimization algorithm of the manipulator when moving along a given cartesian space path is studied.By replacing the independent variable time of a given cartesian space path with path parameters,the basic manipulator trajectory optimization problem,that is,a single-time optimization goal that considers only the manipulator's nonlinear dynamic constraints,joint torque constraints,and zero-speed boundary constraints.The trajectory optimization problem is transformed into a mathematical optimization problem considering multiple constraints.Based on the convex optimization theory,the mathematical optimization problem is solved by discretization,so as to obtain the time-optimal trajectory of the manipulator along a given Cartesian space path.To improve the shortcomings of the basic manipulator trajectory optimization algorithm,by adding kinematic constraints in the optimization model,and adding restrictions on energy consumption and acceleration in the optimization function of the optimization model,so as to obtain improved kinematically constrained single-time target trajectory optimization problems and improved kinematically constrained multi-target trajectory optimization problems.Using the same discretization method to solve,get the improved single-time target and multi-target optimal trajectory.Final,in order to verify the collision detection algorithm and the dual manipulators collision avoidance path planning algorithm proposed in this paper,a dual-manipulator coordination system model was built in the VREP(Virtual Robot Experimentation Platform),and we completed the simulation experiments to verify its effectiveness;in order to verify the trajectory optimization algorithm of the manipulator along the given cartesian space path,we used the form of Simulink-ADAMS joint simulation,the trajectories generated by the basic trajectory optimization algorithm of the manipulator,the improved single-timetarget trajectory optimization algorithm that applies more kinematic constraints and the improved multi-target trajectory optimization algorithm that applies more kinematic constraints are loaded into the Signal Builder module through the EXCEL table,through the Signal Builder module,the joint trajectory signal of the simulation input is generated in real time,and the simulation is obtained by running the simulation platform.Verified the validity.