Online collision avoidance method for command-based manipulators by allocating priority to job consists of PTP commands (Prioritization of specify job and correspondence to job that manipulator can't avoid halfway)

Abstract

In this paper, we introduce an online collision avoidance algorithm for multiple command based manipulators with a concept of job and command priority. Considering application to factory use, we adopt a robot controller which is close to actual industrial controller with a sequence of point-to-point motion command. Previously, our colleagues have developed online collision avoidance methods with interlock algorithm and with advanced collision map. But these two methods have some disadvantages; for example, they cannot restrict to have an collision avoidance motion during commands which must be done continuously such as insertion of a peg into a hole. We introduce a concept of priority with continuity to P-to-P command and job which is a group of some commands; pick an object from a certain position, place an object on a certain position etc. When deadlock is occurred, one robot must get out of the others way. To determine a getting out robot, priority has an important role. When a robot must get out, its priority changes to the same high priority of the other to let other robots on the getting out path move to avoid new collision. With some simulations, we have verified that our new algorithm works well in the case of mutual collision of multiple robot manipulators.