Collision-free path planning for an industrtal robot in configuration space requires mapping obstacles from robot’s workspace into its configuration space. In this paper ,an approach to real-time collision-free path planning for robots in configuration space is presented. Obstacle mapping is carried out by fundamental obstacles defined in the workspace and their images in the configuration space. In order to avoid dealing with unimportant parts of the configuration space that do not thect searching a collision-free path between starting and goal configurations, we construct a free subspace by slice configuration obstacles. In this free subspace, the collision-free path is determined by the A algorithm. Finally, graphical simulations show the effectiveness of the proposed approach. Collision-free path planning for an industrtal robot in configuration space requires mapping obstacles from robot’s workspace into its configuration space. In this paper, an approach to real-time collision-free path planning for robots in configuration space is presented. out by elementary obstacles defined in the workspace and their images in the configuration space. In order to avoid dealing with unimportant parts of the configuration space that do not thect searching a collision-free path between starting and goal configurations, we construct a free subspace by slice configuration obstacles. In this free subspace, the collision-free path is determined by the A algorithm. Finally, graphical simulations show the effectiveness of the proposed approach.