TOWARD EFFICIENT PATH-PLANNING FOR ARTICULATED ROBOTS

Real-time issues are becoming more and more important in robot programming. When a 6-dof manipulator is used, planning obstacle-avoiding paths is a time-consuming activity, usually done in simulation. We present the geometric models and the reasoning techniques we have implemented while realizing a gross motion planner for a manipulator with six revolute joints. First, construction of a problem-oriented representation of the robot working space is explained. Then, the actual trajectory research carried out in our C-space representation is described. The whole C-space is not calcualted; instead, a sequential strategy is used to determine the C-space only for the first two links. Our approximation of the obstacles, which occupy fixed and known positions, greatly speeds the computation, allowing us to reduce the problem to planar geometric reasoning. The work is not limited to theoretical studies or simulations; experiments have been run very thoroughly, with various tests, on a PUMA robot to assess the real efficiency and usability of our software. The method applies to robots in a fixed and known environment. (C) 1995 John Wiley & Sons, Inc.