An Algorithm for CAD-Based Generation of Collision-Free Robot Paths

Generating efficient collision-free paths interactively through computer simulation is one of the main goals of offline programming. These paths can be difficult to create, especially for redundant robots. In addition, the efficiency of the path is dependent upon the expertise of the programmer. Automatic path planning is an attractive option for eliminating these problems.This paper presents a new method for planning collision-free paths for robots with any number of joints [4–7]. It is particularly well suited for use with kinematically redundant robots. In fact, it is the first configuration space algorithm which allows full use of the redundant joints along the entire path. The algorithm is general in that it does not impose restrictions on the robot’s geometry and motion, the payload or the obstacles. It does not try to locate an optimal path. Instead, it attempts to locate an efficient path while mapping a minimal amount of configuration space. The method involves iteratively modifying a connected path between the starting and goal positions to avoid all intervening obstacles. World model information is used to guide the path modification. This approach is of particular value in high dimensional cases for which exhaustive searches are impractical. Two example paths for a seven jointed robot are presented. A discussion of future directions in path planning is included.