Distributed simultaneous-fault tolerant control of distributed networked control systems subject to time-varying delay

This paper presents a distributed simultaneous-fault tolerant control (SFTC) methodology for detecting and accommodating simultaneous multiple-subsystem faults in distributed networked control systems (DNCSs) subject to time-varying delay. In this distributed SFTC architecture, a fault accommodation (FA) component is designed for each subsystem in the DNCS by using local measurements. Each FA component consists of a nominal controller and a fault tolerant controller. And each controller in the distributed FA components is designed by using adaptive approximation technique. A simultaneous-fault is detected when the state tracking error of any subsystem in the DNCS exceeds the corresponding threshold. Prior to the detection of a simultaneous-fault, the nominal controller in each FA component is used for counteracting the effect of uncertainty in its corresponding subsystem. Then the controller in each FA component is reconfigured after simultaneous-fault detection, to compensate for the effect of the local fault in the corresponding subsystem. Under certain assumptions, the stability properties of the distributed SFTC design are rigorously investigated. Simulation results are reported showing the effectiveness of the proposed methodology.