Collision detection between robot arms and people

As the result of an increasing number of robots performing tasks in a range of human life activites, human - robot interaction has become a very active research field. Safety of people around robots is a major concern. This paper presents some research in this context: our aim is to avoid mechanical injure of people interacting with robots. We approach the collision detection problem in a scene with people and several moving robot arms. Fast collision detection for practical motion planning depends on an adequate spatial representation for the objects involved in the scene. The authors have previosly proposed a system that automatically generates a hierarchy of approximations for general objects. The spatial model has interesting properties and has been used in efficient collision detection algorithms between moving robots [8]. In spatial representations, there is a trade-off between generality and efficiency. Some existing approaches claim to be general but they are less efficient. In this paper, we present two extensions to the spatial model. First, the system can deal with a general class of objects, those that are composed of nonhomogeneous generalized cylinders. Secondly, a simple method for automatic converting from a polyhedral representation to such a generalized cylinder is presented. Therefore, we enhance the generality of the system but without compromising the efficiency. With these extensions virtually any object can be dealt with, and particularly those composing the human body.