A new approach to tracking control of networked discrete-event systems

Abstract

This paper presents a method for the tracking control of discrete-event systems that utilise digital communication only if the communication among the subsystems is necessary for solving the current task. The controlled subsystems are modelled by Input/Output (I/O)-automata and their local control aim is to reach given final states autonomously. The necessity of communication arises when there are synchronous state transitions on the state sequence into the final state, which may only be executed simultaneously by a set of subsystems. A new network unit is introduced, which extends each controlled subsystem in order to satisfy these cooperative tasks. It detects, initiates and ensures the simultaneous execution of the synchronous state transitions by means of the digital communication network. It is proved that the networked system is guaranteed to satisfy the local tasks in the networked discrete-event system, while executing the synchronous state transitions only synchronously. A cooperative car assembling process is used to demonstrate the proposed method.