Adaptive collision checking for continuous robot motions within motion constraints

This paper presents an adaptive algorithm for checking collisions over any continuous robot motion set when tasks or constraints are given. As robots have begun to operate in human environments, which are unstructured and dynamically changing, the need for on-line robot planning and control strategies has increased. In implementing an on-line system, a fast and reliable collision checking method for continuous paths is a critical element. However, since external objects move unexpectedly, collision checking along the continuous path of a robot´s motion suffers from increased uncertainty. Furthermore, computing the desired motion path or trajectory of a complex robotic task is very complex and slow. Therefore, we have developed a new collision checking strategy that can be applied to many types of motions that satisfy many given constraints. Our algorithm defines the applicable robot motions in a constraint-based manner, which is suitable for the multiple-task motion of a complex robot. This method can check the collision for the entire motion by finding the worst case with a small amount of computation, so that we can use the method for on-line applications. Moreover, our algorithm has a feature of adaptive resolution, which provides advantages in dynamically changing environments. The proposed method has been tested on high d.o.f. robots and the experimental results show that the method is suitable for on-line applications of multiple-tasks.