Point-to-point and multi-goal path planning for industrial robots

This article presents contributions in the field of path planning for indus trial robots with 6 degrees of freedom. This work presents the results of o ur research in the last 4 years at the Institute for Process Control and Ro botics at the University of Karlsruhe. The path planning approach we presen t works in an implicit and discretized C-space. Collisions are detected in the Cartesianworkspace by a hierarchical distance computation. The method i s based on the A* search algorithm and needs no essential off-line computat ion. A new optimal discretization method leads to smaller search spaces, th us speeding up the planning. For a further acceleration, the search was par allelized. With a static load distribution good speedups can be achieved. B y extending the algorithm to a bidirectional search, the planner is able to automatically select the easier search direction. The new dynamic switchin g of start and goal leads finally to the multi-goal path planning, which is able to compute a collision-free path between a set of goal poses (e.g., s pot welding points) while minimizing the total path length. (C) 2001 John W iley & Sons, Inc.