Abstract: The existing collision-freemotion planning algorithms based on configuration space (C-Space) need to find the boundaries of C-space obstacles by solving C-space, which will cost much computation and memories for redundant manipulators with larger degrees of freedom (DOF). A novel algorithm was proposed to find the collision-free path in C-space by testing motion directions without solving C-space. This algorithm contained four sub-algorithms: the collision detection algorithm, the collision free target configuration solver, the collision-free path-searching algorithm and the path smoothing algorithm. Given the desired position and attitude of the end-effector, the target configuration solver calculated a collision-free target onfiguration. then the path-searching algorithm found a collision-free path with C-space  obstacle boundaries unknown. Finally, the path smoothing algorithm smoothed the obtained path. To verify the effectiveness of the algorithm, two numerical examples were carried out. And the results indicatethat the algorithm is efficient and can be used in fast motion planning for redundant manipulators in space applications.

Key words: Redundant manipulators, Motion planning, Collision avoidance, Configuration space