Research On The Algorithm Of Obstacle Avoidance Path Planning For Manipulators For Grasping Operations

With the advancement of equipment intelligence,manipulators are increasingly used in the production and processing industries.However,most of manipulators currently used in the industry are operated according to a fixed trajectory set in advance or remotely controlled by a professional.They can only be operated in the specified trajectory.These manipulators are unable to adapt to more complex working space.Therefore,path planning algorithm in manipulator grasping task is studied in this paper.Main research topics includes system modeling of manipulator,collision detection based on special envelope model,path planning based on artificial potential field method and A-star algorithm,simulation experiments and analysis of experimental results.The details are as follows:(1)The D-H method is used in the construction of mathematical models of manipulator in this paper.The method solves the transformation matrix between the links.After multiple matrix transformations between different links,this method establishes the pose transformation relationship from the pedestal to the end link.(2)By comparing multiple collision detection models,an object collision detection method based on special envelope model is designed.In the workspace,the cylinder is used to envelop the manipulator link,the ellipsoid is used to envelop the obstacle.This method reduces the amount of calculation of collision detection and improves the search rate of spatial information.(3)By comparing common path planning algorithms,the path planning method based on artificial potential field method and A-star algorithm is proposed in this paper.The defects of artificial potential field method are improved in two aspects: 1)For the problem that the traditional algorithm is prone to local extremum,the corresponding detection mechanism is formulated in this paper.The adaptive method is used to calculate the temporary target position when extreme values occur.Meanwhile,A-star algorithm is used to control the motion of manipulator to escape to the extremum point.2)For the problem of the critical region between targets and obstacles,the target distance parameter is added to the traditional repulsion field potential function in this paper.This method constrains the infinite growth of repulsion and breaks the equilibrium of the field around the target.Finally,manipulator can be guided to reach the desired posture smoothly.(4)In this paper,MATHEMATICA software is used to build the simulation platform,the algorithm of this paper is compared with similar algorithms in various scenarios.The final results show that the proposed algorithm has advantages in dealing with obstacle avoidance path planning of manipulator.The algorithm is highly robust in the face of more complex workspaces.