This paper proposed an improved RRT algorithm to solve the problem that the traditional target offset RRT was easy to fall into local optimum in the environment where there were many obstacles such as yarn racks, placing platforms and other packages during the package handling process. It established the collision detection model by geometric envelope method, and added the distance coefficient g to keep a safe distance between the end of the manipulator and the obstacle. It proposed a random action selection strategy to select the expansion action before each expansion of the tree, and proposed a weakening target offset strategy to offset the extension direction according to the position of X_goal relative to the X_near and X_rand line. According to the vertical distance limit method and cubic spline interpolation, it optimized the initial path, and finally obtained a smooth path. Through simulation comparison with RRT algorithm, M-RRT algorithm, RRT algorithm with added gravity coefficient and improved RRT^* algorithm, the maximum decrease in path length was 23.3%, the maximum decrease in time was 82.5%, and the distance from obstacles was always more than 50 mm. The results show that the algorithm improves the efficiency and safety of the manipulator handling.

[2023-03-30] Accepted Paper /doc/2023.02.0017/v1

[2023-09-05] Printed Article /doc/2023.02.0017/v2