Event-triggered fault estimation and accommodation design for linear systems

The problem of event-triggered active fault-tolerant control (E-AFTC) of discrete-time linear systems is addressed in this paper by using an integrated design of event-triggered fault/state estimator with a fault-tolerant controller. An event-triggered observer is proposed which can simultaneously provide an estimate of the system states and faults. Through an event-triggered transmission mechanism it is shown that the amount of data sent to the observer module is significantly reduced. Moreover, an observer-based fault-tolerant controller based on fault and state estimates is obtained. A robust H_∞ formulation of the problem is given that guarantees stability of the resulting closed-loop system, attenuates the effects of external disturbances and compensates the effects of the fault. Linear matrix inequality (LMI) sufficient conditions are derived to simultaneously obtain the observer and controller parameters and the event-triggered condition. Simulation results for an autonomous remotely operated vehicle (ROV) is given to illustrate the effectiveness of the proposed design methodology.

I. Introduction

As opposed to conventional periodic digital control systems, event-triggered feedback control design that drives the control action aperiodically has received considerable attention in recent years [1]. The basic idea of event-triggered control is that the control action is only driven when required and it is determined based on a certain condition on plant measurements, known as the event-triggering mechanism [2], [3]. This new approach reduces the usage of computational and communication resources without compromising on the overall desired system performance [4]. It is therefore useful for practical applications especially when communications are costly or limited [5], [6].