Coordination and Control of Distributed Discrete Event Systems under Actuator and Sensor Faults

TL;DR

This paper develops a formal automata-based framework for designing fault-tolerant controllers in distributed discrete event systems, ensuring safety despite actuator and sensor faults through synthesis and coordination schemes.

Contribution

It introduces necessary and sufficient conditions for fault-tolerant supervisor synthesis and applies an assume-guarantee coordination scheme for both nominal and faulty systems.

Findings

Established conditions for fault-tolerant supervisor existence

Synthesized local post-fault supervisors to maintain safety

Validated approach with a multi-robot coordination example

Abstract

We investigate the coordination and control problems of distributed discrete event systems that are composed of multiple subsystems subject to potential actuator and/or sensor faults. We model actuator faults as local controllability loss of certain actuator events and sensor faults as observability failure of certain sensor readings, respectively. Starting from automata-theoretic models that characterize behaviors of the subsystems in the presence of faulty actuators and/or sensors, we establish necessary and sufficient conditions for the existence of actuator and sensor fault tolerant supervisors, respectively, and synthesize appropriate local post-fault supervisors to prevent the post-fault subsystems from jeopardizing local safety requirements. Furthermore, we apply an assume-guarantee coordination scheme to the controlled subsystems for both the nominal and faulty subsystems so as to achieve the desired specifications of the system. A multi-robot coordination example is used to illustrate the proposed coordination and control architecture.