Implementation of hierarchical and distributed multitasking control for industrial multiple robotic systems

This paper deals with the problem of designing discrete event net based controllers that guarantee user task specifications for industrial multiple robot systems. Based on condition-event models of robotic activities, extended Petri nets are adopted as a tool for expressing independent and cooperative tasks by industrial autonomous intelligent robots. Net models representing inter-robot cooperation with synchronized interaction are presented, and the design of a net based real-time distributed multitasking control system which coordinates the parallel activities of the robot controllers through the transmission of commands and the reception of status, is described. Software implementation of the multitasking control using multithreads is also described for distributed simulation and experiments of an example multi-robot cell.