Networked Control system with intermittent observations: FDI/FTC design based on Interacting Multiple Model approach

Abstract

This paper presents a FTC approach based on sensor masking principle in the special case of control system integrating a wireless sensor network. In the presence of sensor faults, the faulty measurements corrupt directly the behaviour of the closed-loop systems. With wireless transmission, packet losses are acting as additional sensor faults. Since the controller aims at cancelling the error between the measurement and its reference input, the real outputs will in such networked control system deviate from the desired value and may drive the system to its physical limitations or even to instability. The proposed method makes possible the faults compensation based on a classical Interacting Multiple Model developed in the framework of multiple sensors failures. The IMM involved in Networked Control system provides simultaneously on-line packet losses detection, and isolation and also a suitable state estimation. Based on particular knowledge on packet losses, sensor fault-tolerant controls are obtained by computing a new control law using a fault-free estimation of the faulty element to avoid faults to develop into failures and to minimise the effects on the system performance and safety.