When a collision-free movement of a manipulator is planned, it is necessory to detect the interference among manipulator links and obstacles. Until now, the detection has been simplified by adding various conditions mainly. But this paper proposes an interference detection method which is relatively general and is simple to calculate. Manipulator links and obstacles are approximated by convex polyhedra or these combinations. And a necessory and sufficient condition of interference between two convex polyhedra is expressed by using a relatively simple function which uses only a relation of these faces and vertices.
And this function can be transformed easily to the one whose argument is a joint vector by using the notation of Denavit et al. Then, this method is well applied to planning collision-free movement of a manipulator because of detecting interference also in the joint space of all joint vectors.