基于目标导向采样的机器人改进概率路图法研究

Improved Probability Path Graph Method for Robots Based on Goal⁃oriented Sampling

鉴于采样的完全随机性,传统PRM算法往往较难适用于具有狭窄通道工作环境下的机器人路径规划。为此,本文提出了一种融合全局目标导向采样、局部节点增强的改进概率路图法(Improved PRM),并将其应用于平面栅格地图场景及六自由度机器人的路径规划。首先将全局目标导向采样与随机采样有机结合,通过混合采样的方式来提高全局采样点落在狭窄通道内的概率,实现启发式地图增强;其次,经由节点权重思想对位于狭窄通道中的节点进行提取,并利用基于高斯分布的局部节点增强策略在狭窄通道中扩展新节点,增强地图连通性,以提高路径规划的成功率;最后,采用冗余节点剔除策略对算法规划的初始路径进行优化。Improved PRM算法在平面栅格地图中的仿真结果表明,该算法对于机器人路径规划的成功率可达89.3%以上,且综合评价指数及路径质量评价指数均高于其他算法;在六自由度机器人的仿真实验中,Improved PRM算法得到的平均路径代价比传统PRM算法降低约42.7%,成功通过狭窄通道概率也比传统PRM提高68个百分点。因此,相比文中所提其他算法,在具有狭窄通道的工作环境中,改进概率路图法在提高路径规划成功率、减少路径节点、保证路径质量等方面具有优势。

Due to the complete randomness of sampling,the traditional PRM algorithm was often difficult to be applied to the robot path planning in the working environment,including narrow channels.To this end,an improved probabilistic roadmap method(Improved PRM)integrating global goal⁃oriented sampling and local node enhancement was proposed and utilized to the path planning of a planar grid map scene and a 6⁃DOF robot.Firstly,the global goal⁃directed sampling was combined with the random sampling in the proposed Improved PRM,and the probability of global sampling points falling into narrow channels was raised by the mixed sampling,so as to achieve the heuristic map enhancement.Secondly,nodes in narrow channels were extracted by using the node weight idea,and a local node enhancement strategy based on Gaussian distribution was used to expand new nodes in narrow channels to enhance the connectivity of the map and the success rate of path planning.Finally,the redundant node elimination strategy was presented to optimize the initial path planned by the algorithm.The simulation results of the Improved PRM algorithm in the planar grid map showed that the success rate of the algorithm for robot path planning was more than 89.3%.Besides,the comprehensive evaluation and path quality evaluation were both higher than that of other algorithms.In the simulation experiment of a 6⁃DOF robot,the average path cost obtained by the Improved PRM algorithm was about 42.7%lower than that of the traditional PRM algorithm.Meanwhile,the probability of successfully passing through the narrow channel was also 68 percentage points higher than that of the traditional PRM algorithm.Therefore,compared with other algorithms,the Improved PRM algorithm had advantages in improving the success rate of path planning,reducing path nodes,and ensuring path quality in the working environment with narrow channels.