Research On Motion Planning Method Of Industrial Manipulator For Obstacle Avoidance

With the improvement of factory automation,the industrial manipulator has been widely used in the modern manufacturing industry.However,at present,most of the manipulators use the manual teaching method for motion planning,which is not only time-consuming and laborious,but also unable to adapt to the changing working environment.In order to solve the above problems and make the manipulator more intelligent,this paper takes ROKAE XB7 s,a commonly used industrial 6-DOF manipulator,as the object,and studies the motion planning method of the manipulator.The main research contents include kinematic modeling of manipulator,collision detection method,path planning method,and trajectory planning method,which are as follows:Firstly,the kinematic analysis and model establishment of the manipulator are carried out.The forward and inverse kinematics equations of the robot are deduced.The D-H method is used to model the kinematics of the ROKAE XB7 s manipulator,and the Monte Carlo method is used to solve the workspace of the manipulator in MATLAB.Finally,the point cloud map of the workspace is obtained.The spherical envelope method is used to model the obstacle,the cylindrical envelope method is used to simplify the manipulator according to the structural characteristics of the manipulator,and the specific collision detection method is designed.Secondly,this paper proposes a two-phase motion planning algorithm named Metropolis-RRT~*(M-RRT~*)based on the Metropolis acceptance criterion.To efficiently obtain the initial path and start the optimal path search phase earlier,an asymptotic vertex acceptance criterion is defined in the initial path estimation phase of M-RRT~*.To improve the convergence rate of the algorithm,a nonlinear dynamic vertex acceptance criterion is defined in the optimal path search phase,which preferentially accepts vertices that may improve the current path.Then,the trajectory planning method of the manipulator is studied.Various methods of Cartesian space trajectory planning and joint space trajectory planning are discussed respectively,and the conclusion that joint space trajectory planning is easy to control and simple to calculate is obtained.In order to make the trajectory of the manipulator locally controllable and meet the relevant constraints.In this paper,the quintic B-spline curve is used to complete the trajectory process,and its derivation process is given in detail.Finally,the effectiveness of the manipulator motion planning method is verified.By combining the proposed path planning algorithm with the collision detection method,a collision-free path is found in the three-dimensional space,and the path is optimized and given time information by the proposed trajectory planning method.The Robotics Toolbox is used in MATLAB to verify the end path for the manipulator to complete the movement and the movement trajectory of each joint of the manipulator is obtained.