Unknown Network-induced Delay Research Articles

Online fault detection for networked control system with unknown network-induced delays

This paper focuses on the online fault detection problem for networked control systems with unknown network-induced delays. In the study, a fault detection model was established for the impact of the unknown network-induced delay. Based on the model, the fault detection filter was constructed, and then the corresponding fault detection problem was converted to an optimisation problem. Finally, a numerical simulation shows that the proposed online fault detection algorithm is not only sensitive to the fault, but also robust to the unknown disturbance caused by the delays.

Online fault detection for networked control system with unknown network-induced delays

Online fault detection for networked control system with unknown network-induced delays

Fault detection of networked control systems with uncertain time-varying delay and quantization error

Problems related to fault detection of networked control systems (NCSs) with both uncertain timevarying delay and quantization error are studied in this paper. A novel model with the form of polytopic uncertainty is given to represent the influences of both the time-varying delay and the quantization error, and then the reference model based method is used to design the residual generator that is robust to both unknown network-induced delay and unknown inputs. A numerical example is also given to illustrate the merits of the presented method. The proposed method can be regarded as an extension of the authors’ former work, which can only deal with time-varying delay.

Fault Detection of Networked Control Systems Based on Optimal Robust Fault Detection Filter

Fault detection of networked control systems (NCSs) with random and unknown network-induced delay that might be larger than one sampling period is studied in this paper. First, influence caused by network-induced delay is transformed into structured modeling error, then an existent continuous time domain robust fault detection method based on reference model is extended to discrete time domain and applied to fault detection of networked control systems. The proposed method can be easily implemented by Matlab LMI toolbox, and its performance is finally evaluated by a simulation example.

Fault detection and isolation for a kind of NCSs with Markov Delays

Abstract A new approach for fault detection and isolation (FDI) of Networked Control Systems (NCSs) is proposed in this paper. The paper first regards NCSs with unknown network-induced delay as a Jump Markov linear system (JMLS) with unknown input, then gives a Bayesian estimation of the JMLS based on Unknown Input Kalman filter (UIKF), and finally uses the estimation results to detect and isolate faults based on Log-likelihood ratio (LLR) approach. Simulation example shows that the method is robust to random networked induced-delay and unknown input.

Fault detection of NCS based on eigendecomposition, adaptive evaluation and adaptive threshold

A method for fault detection (FD) of networked control systems with unknown network-induced delay and unknown input based on eigendecomposition, adaptive evaluation and adaptive threshold is proposed in this paper. In the method, a known structure matrix of network-induced delay which is supposed to be smaller than one sampling period is extracted by eigendecomposition and an observer based residual generator is constructed. Then an adaptive evaluation function is proposed to ensure the optimal robustness to network-induced delay and unknown input at the evaluation stage based on the Parity Space approach. Finally, based on the estimation of the maximal influence of unknown random delay and unknown input on the evaluation function, adaptive threshold is designed to enhance robustness of the FD system and reduce the miss detection rate as much as possible.

FAULT DETECTION OF NCS BASED ON EIGENDECOMPOSITION AND PADE APPROXIMATION

In this paper, a new method for fault detection of Networked Control Systems (NCSs) with random delay based on eigendecomposition and Padé Approximation is proposed. In the method, a so-called distribution matrix corresponding to unknown network-induced delay is first obtained through eigendecomposition, then it is further transformed into a vector by using Padé Approximation to make the decoupling easier. Finally, the robustness to random network-induced delay is realized by decoupling from the distribution vector. The method is compared with the conventional fault detection approach without considering network-induced delay and the existing Taylor Expansion based fault detection approach for NCSs.