A hierarchical collision-free path planning algorithm for robotics

A hierarchical path planning algorithm is proposed to plan a collision free path for mobile robots and robot manipulators in an environment with stationary obstacles as well as multi-robot manipulators in a common workspace. The proposed algorithm consists of two parts: tunnel finding and path planning. The tunnel finding algorithm constructs a free subspace in which start and goal configurations are included and a collision free path candidate can be found. Specifically, the tunnel is constructed by using big cells defined as a group of several basic cells. The path planning algorithm then plans a path in the tunnel. In addition to the capability of planning a collision free path in an environment with stationary obstacles, the proposed algorithm is capable of finding a collision-free path for multi-robot manipulators in a common workspace. To show the validity of the proposed algorithm, some numerical examples are illustrated for mobile robot and multiple robot manipulators in a common workspace.