Petri net based hierarchical and distributed implementation of multiple robotic manufacturing systems

This paper deals with modeling and implementation problems encountered in complex robotic systems design using multiple robots. Based on conceptual condition-event models of robotic activities, extended Petri nets are adopted as a tool for expressing independent and cooperative robotic tasks and a method is described for their direct implementation. Net models representing inter-task cooperation with synchronous or asynchronous interaction are presented, and the design of a coordinator which coordinates the parallel activities of the local robot controllers through the transmission of commands and the reception of status, is described. Detail explanations of how the control system proceeds when used in the inter-task cooperation on an example robotic cell, are provided.