An approach to collision avoidance issues for redundant manipulator

This paper describes a novel method to plan the collision-free trajectory for robot manipulator. When several obstacles are fixed on the ground or in the air in the workspace, the shortest path between two ordered points, which represents a sequence of points indicating the positions for manipulator tip, and the manipulator configurations corresponding the tip positions are planned with the method. The approach proposed consists of two parts. First, the shortest path for the manipulator tip is planned, which detours around the obstacles. When each obstacle is recognized as an aggregate of convex polyhedra, it is shown that the shortest path consists of linked segments and easily calculated by solving the recursive quadratic equations. Next, successive motion for the manipulator to avoid collisions against the obstacles is planned, since the structure of manipulator is not considered in the solved path. The configurations of the manipulator is determined by depending on the tip position along the path and by referring the distances among manipulator links and obstacles