Discrete Event-Triggered Robust Fault-Tolerant Control for Nonlinear Networked Control Systems withα-Safety Degree and Actuator Saturation

Wei Li,Yajie Li

doi:10.1155/2015/590598

Abstract

This paper deals with the discrete event-triggered robust fault-tolerant control problem for uncertain nonlinear networked control systems (NNCSs) withα-safety degree. A discrete event-triggered communication scheme (DETCS) is initially proposed, and a closed-loop fault model is subsequently established for NNCSs with actuator saturation under the DETCS. Based on an appropriately constructed delay-dependent Lyapunov–Krasovskii function, sufficient conditions are derived to guarantee the asymptotic stability of NNCSs under two different event-triggered conditions and are established as the contractively invariant sets of fault tolerance withα-safety degree. Furthermore, codesign methods between the robust fault-tolerant controller and event-triggered weight matrix are also proposed in terms of linear matrix inequality. The simulation shows that the resultant closed-loop fault NNCSs possesses a high safety margin, and an improved dynamic performance, as well as a reduced communication load. A comparative analysis of the two event-triggered conditions is discussed in the experiment section.

Highlights

With the increasing scale and complexity of networked control systems (NCSs), high safety and reliability have ceased to be extravagant demands for NCSs
In consideration of actuator failures, the irrelevant augmented matrix was introduced into the Lyapunov function in [13], and the reliability control problem was studied for nonlinear networked control systems (NNCSs) with random time delay
Based on event-triggered condition (5) or (6) under the discrete event-triggered communication scheme (DETCS), when we consider the actuator saturation constraints and actuator failures, the goal of codesign between network communication and the robust fault-tolerant control for uncertain NNCSs with α-safety degree is to seek the statefeedback controller gain Kj (j = 1, 2, . . . , r) and discrete event-triggered weight matrices, Φ1 and Φ2, or Φ, which can ensure that the nonlinear networked closed-loop fault systems (NNCFSs) (17) satisfies the following conditions

Summary

Introduction

With the increasing scale and complexity of networked control systems (NCSs), high safety and reliability have ceased to be extravagant demands for NCSs. In consideration of actuator faults, a time delay dependent condition with the robust stability was derived for NNCSs in [17], where the design method for the robust H∞ fault-tolerant controller was given under the terms of a cone complementarity linearization algorithm. Several performance indexes, such as α-stability, H∞ performance index, and H2 performance index, were introduced into the fault-tolerant design field for NNCSs [18], and some robust satisfactory fault-tolerant control problems were systematically studied therein for uncertain

Methods

Results

Conclusion