Obstacle Avoidance Path Planning For Palletizing Robots Based On Improved RRT-Connect Algorithm

With the rapid development of science and technology,industrial production is moving in the direction of intelligence,and more and more factory lines are using industrial palletizing robots to replace manual workpiece or material gripping and stacking.However,when the operating environment of the industrial palletizing robot changes,the robot needs to be re-programmed to meet its operating requirements,which is inefficient and less adaptable,and the paths shown are not optimal.To address this problem,this paper investigates the obstacle avoidance path planning algorithm of a six-degree-of-freedom industrial palletizing robot,with the following main work:Firstly,the positional description and coordinate transformation used in the mathematical modeling of the palletizing robot are introduced,and the mathematical model of the robot is established by using the improved D-H parameter method,based on which the forward and inverse kinematic equations of the robot are derived,and the derived kinematic equations are verified by simulation software.And the working space of the palletizing robot is solved by Monte Carlo method,and its 3D working space point cloud map is obtained in the simulation software.Then the trajectory planning of the palletizing robot is carried out with jtraj function and ctraj function,which lays the foundation for the obstacle avoidance path planning in the later paper.Secondly,the palletizing robot operation environment is complex,in order to avoid collision with obstacles in the workspace,collision detection analysis is carried out,and the palletizing robot linkage studied in this paper is enveloped by the cylindrical envelope box method,and the obstacles in i ts workspace are enveloped by the sphere envelope box method to further simplify the analysis of collision detection between the linkage and obstacles of the palletizing robot,and the collision detection is designed Flowchart.To address the problems of randomness,slow convergence,the generated paths are not optimal paths and easily fall into local optimality in the path planning of standard RRT algorithm,RRT-Connect algorithm and artificial potential field method,this paper proposes an obstacle avoidance path planning algorithm using artificial potential field method to improve the RRT-Connect algorithm,that is,using the target gravitational function in the artificial potential field method to guide the node expansion,and the repulsive function dynamically adjusts the step size.At the same time,to solve the problem of redundant nodes and unsmoothed paths,the redundant path nodes are removed using the pruning function,and three B-sample curves are taken to smooth the planned paths and improve the quality of the paths,and the experimental steps of the improved RRT-Connect algorithm are represented in a flowchart.Finally,experimental simulations are conducted to compare and analyze the nodes using the improved RRT-Connect algorithm with the standard RRT algorithm and RRT-Connect in two-dimensional and three-dimensional environments first,and then a three-dimensional environment with different numbers of obstacles is set up to conduct comparative experiments on obstacle avoidance path planning for palletizing robots.Connect algorithm has higher advantages in path smoothing,path length and time of path planning.The simulation experiments were done in Robotstudio software,and the paths obtained were smooth and jitter-free,which verified the feasibility and reasonableness of the improved algorithm in this paper.