Xiao GuangZhou, Wu Tong, Weng Rui, Zhang RuiXian, Han YueJiang, Dong YiFei, Liang Ye
School of Astronautics, Harbin Institute of Technology, Harbin, 150001 China.
Faculty of Computing, Harbin Institute of Technology, Harbin, 150001 China.
Sci China Technol Sci. 2023;66(5):1205-1213. doi: 10.1007/s11431-022-2238-1. Epub 2023 Apr 12.
This paper is concerned with the issue of path optimization for manipulators in multi-obstacle environments. Aimed at overcoming the deficiencies of the sampling-based path planning algorithm with high path curvature and low safety margin, a path optimization method, named NA-OR, is proposed for manipulators, where the NA (node attraction) and OR (obstacle repulsion) functions are developed to refine the path by iterations. In the iterations of path optimization, the node attraction function is designed to pull the path nodes toward the center of their neighbor nodes, thereby reducing the path curvature and improving the smoothness. Also, the obstacle repulsion function is developed to push the path nodes out of the potentially unsafe region by generating a repulsive torque on the path nodes, thus improving the safety margin of the motion. By introducing the effect of NA-OR, the optimized path has a significant improvement in path curvature and safety margin compared with the initial path planned by Bi-RRT, which meaningfully enhances the operation ability of manipulators for the applications that give a strong emphasis on security. Experimental results on a 6-DOF manipulator in 4 scenarios demonstrate the effectiveness and superiority of the proposed method in terms of the path cost, safety margin, and path smoothness.
本文关注多障碍物环境中机械手的路径优化问题。针对基于采样的路径规划算法存在路径曲率高、安全裕度低的不足，提出了一种适用于机械手的路径优化方法，即NA-OR，其中通过开发NA（节点吸引）和OR（障碍物排斥）函数来迭代优化路径。在路径优化的迭代过程中，节点吸引函数被设计用于将路径节点拉向其相邻节点的中心，从而降低路径曲率并提高平滑度。此外，障碍物排斥函数通过在路径节点上产生排斥扭矩将路径节点推出潜在的不安全区域，从而提高运动的安全裕度。通过引入NA-OR的作用，与Bi-RRT规划的初始路径相比，优化后的路径在路径曲率和安全裕度方面有显著改善，这对于高度重视安全性的应用场景而言，有意义地增强了机械手的操作能力。在4种场景下对6自由度机械手进行的实验结果证明了所提方法在路径成本、安全裕度和路径平滑度方面的有效性和优越性。
