Scheduling robotic assembly tasks using Petri nets

In this paper, the authors present an approach to robotic assembly task scheduling which yields suboptimal solutions. The robotic assembly system involves two robots working in the same workspace. Collision between the two robot arms is avoided by the use of the uniform cell decomposition approach. Timed Petri nets are used to model the operations performed by the two robot arms. The execution times of the operations are determined during the generation of the reachability graph. Approaches which are used to partially generate the reachability graph and determine the minimum-time paths are proposed