Fault detection method for networked control system

Abstract

The invention provides a fault detection method for a networked control system. The fault detection method comprises the following steps: firstly, two independent Markov chains are used to respectively describe a sensor-to-controller delay and a controller-to-actuator delay, and the networked control system is modeled as a control system with two Markov chains; on the basis, a fault detection filter is constructed and a closed-loop system model is established by using a state augmentation method; and after that, the condition that the closed-loop system is stochastically stable and satisfies the H infinity performance is obtained in the form of a matrix inequality, a controller and filter gain matrix and a solution method of the H infinity reduction level are given, and the relation between the transition probability and the minimum H infinity reduction level is obtained. Examples show that a fault filter obtained by the proposed method is not only sensitive to faults, but also has good robustness to external disturbance, so that the H infinity fault detection problem of the networked control system under the condition that the transition probabilities of the sensor-to-controller delay and the controller-to-actuator delay are both partially unknown is solved.

Description

technical field [0001] The invention relates to the field of computer network control, in particular to a fault detection method for a network control system. Background technique [0002] Networked control system (NCS) is a closed-loop feedback control system composed of a shared network. It has the advantages of low cost, flexible structure, and easy maintenance. It has been widely used in the field of complex industrial control. However, the introduction of the network inevitably produces problems such as time delay and packet loss, which increases the complexity of the system and brings new challenges to the reliability of NCS. The problem of fault detection in NCS has received extensive attention and many research results have emerged. [0003] In NCS, the network delay is random in many cases, and the random delay is often modeled as a finite-state Markov chain. The advantage of this method is that it can describe the dependency between the delay at the current moment...

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Problems solved by technology

Use two independent Markov chains to describe the S-C delay and C-A delay respectively. Under the condition that the transition probabilities of the S-C delay and the C-A delay are partially unknown, that is, for figure 1 The control system shown for NCS fault detection has not been reported yet

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