An indispensable feature of an intelligent manipulator is its capability to quickly plan a short and safe path in the presence of obstacles in its workspace. Among the path planning methods, the probabilistic roadmap (PRM) method has been widely applied in path planning for a high-dimensional manipulator to avoid obstacles. However, its efficiency remains disappointing when the free space of manipulators contains narrow passages. To solve this problem, an improved PRM method is proposed in this paper. Based on a virtual force field, a new sampling strategy of PRM is presented to generate configurations more appropriate for practical application in the free space. Correspondingly, in order to interconnect these configurations to form a roadmap, a new connection strategy is designed, which consists of three stages and can gradually improve the connectivity of the roadmap. The contributions of this paper are as follows. The new sampling strategy can increase the sampling density at the narrow passages of the free space and reduce the redundancy of the samples in the wide-open regions of the free space; the three-stage connection strategy for interconnecting samples can ensure a high-connectivity roadmap; through synthesizing the above strategies, the improved PRM method is more suitable for path planning of manipulators to avoid obstacles efficiently in a cluttered environment. Simulations and experiments are carried out to evaluate the validity of the proposed method, and the method is available for manipulator of any degrees of freedom.

智能机械手的一个不可或缺的特性是它能够在其工作空间中存在障碍物的情况下快速规划一条短而安全的路径。在路径规划方法中，概率路线图（PRM）方法已广泛应用于高维机械手的路径规划以避开障碍物。然而，当机械手的自由空间包含狭窄的通道时，它的效率仍然令人失望。为了解决这个问题，本文提出了一种改进的PRM方法。基于虚拟力场，提出了一种新的 PRM 采样策略，以生成更适合自由空间实际应用的配置。相应地，为了将这些配置互连起来形成路线图，设计了一种新的连接策略，由三个阶段组成，可以逐步提高路线图的连通性。本文的贡献如下。新的采样策略可以提高自由空间狭窄通道的采样密度，减少自由空间宽阔区域的样本冗余；互连样本的三阶段连接策略可以确保高连接性路线图；通过综合上述策略，改进的 PRM 方法更适合机械手的路径规划，以在杂乱环境中有效避开障碍物。仿真和实验验证了该方法的有效性，该方法适用于任意自由度的机械手。新的采样策略可以提高自由空间狭窄通道的采样密度，减少自由空间宽阔区域的样本冗余；互连样本的三阶段连接策略可以确保高连接性路线图；通过综合上述策略，改进的 PRM 方法更适合机械手的路径规划，以在杂乱环境中有效避开障碍物。仿真和实验验证了该方法的有效性，该方法适用于任意自由度的机械手。新的采样策略可以提高自由空间狭窄通道的采样密度，减少自由空间宽阔区域的样本冗余；互连样本的三阶段连接策略可以确保高连接性路线图；通过综合上述策略，改进的 PRM 方法更适合机械手的路径规划，以在杂乱环境中有效避开障碍物。仿真和实验验证了该方法的有效性，该方法适用于任意自由度的机械手。互连样本的三阶段连接策略可以确保高连接性路线图；通过综合上述策略，改进的 PRM 方法更适合机械手的路径规划，以在杂乱环境中有效避开障碍物。仿真和实验验证了该方法的有效性，该方法适用于任意自由度的机械手。互连样本的三阶段连接策略可以确保高连接性路线图；通过综合上述策略，改进的 PRM 方法更适合机械手的路径规划，以在杂乱环境中有效避开障碍物。仿真和实验验证了该方法的有效性，该方法适用于任意自由度的机械手。