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A novel fault diagnose method is presented for the nonlinear systems with coupled fault and disturbance via adaptive observer technique. Residual matrix is used in this paper to describe the values of unknown inputs. Instead of adding robustness on the estimate states, this novel observer structure focuses on eliminating the disturbance signal on the residual matrix by using vector unitization so...
In this paper, the fault detection problem of feedback control systems with Signal-to-Noise Ratio (SNR) constrained channels is studied. A residual generation based on system model is designed to guarantee the best trade-off between sensitivity to fault and robustness to system disturbance as well as channel noise. A norm-based residual evaluation function is used and an on-line dynamic threshold...
In this study a strain gage load cell as a S model has been designed which is used for measuring weight of elevator. Four methods of fixing and balancing Whetstone Bridge were considered and one way was achieved eventually which was given the best Whetstone Bridge's output. For amplifying and measuring of changing resistance and voltage in Whetstone Bridge four current ways of amplifying and measuring...
The paper deals with the problem of fault detection and isolation in machining centers, which are the basis of FMSpsila. The problem is of paramount importance since an effective diagnostic system can lead to a significant increase in the autonomy of an automated system. The paper considers a special case study: an hydraulic circuit which blocks and unblocks the pallet on the rotary table in a machining...
Networked control systems (NCS) are an active area of research within control and estimation. Networked control systems have many advantages by comparison with the traditional ones. The fault detection problem is studied in this paper for a class of linear networked control systems (NCS) with communication delays. Aim is to generate residual signals which, in the fault free case, are supposed to be...
In multivariate statistic process control (MSPC), the projection methods, in particular, the principal component analysis (PCA) proved their efficiencies to the problems of fault diagnosis. In this paper, we explained the use of this tool and its major interest. A projected observation in the PCA space has a score distance (SD) in the principal component subspace and an orthogonal distance (OD) or...
Principal component analysis (PCA) is a powerful fault detection and isolation method. However, the classical PCA which is based on the estimation of the sample mean and covariance matrix of the data is very sensitive to outliers in the training data set. Usually robust principal component analysis was applied to remove the effect of outliers on the PCA model. In this paper, a fast two-step algorithm...
This paper addresses fault detection and isolation (FDI) problem using a sliding mode fuzzy observer on the basis of a uncertain Takagi-Sugeno (T-S) fuzzy model. First, a robust fuzzy observer with respect to the uncertainties is designed. The convergence of the fuzzy observer is performed by the search of suitable Lyapunov matrices. It is shown how to synthesis observers using a set of linear matrix...
For sequential jumps detection, isolation and estimation in discrete-time stochastic linear systems, (A.S. Wilsky et al., 1976) have developed the generalized likelihood ratio (GLR) test. After each detection and isolation of one jump, the treatment of another possible jump is obtained by a direct state estimate and covariance incrementation of the Kalman filter originally designed on the jump-free...
This paper addresses the fault detection issue of large scale wind turbine systems. The underlying problem is very critical to enhance the reliability and reduce the cost of maintenance of wind turbines. In this work, mixed Hinfin/H- index observer is utilized to generate the residual for fault detection purpose. The employed observer is optimal in the sense that it is the least sensitive to the unknown...
To improve the performance properties of heavy vehicles, i.e. to reduce the risk of emergencies, improve passenger comfort and road holding, a reconfigurable fault-tolerant control design of the active suspension is performed. When a fault (loss in effectiveness) occurs at one of the suspension actuators a reconfiguration is needed in order to maintain the same performance level. The proposed reconfiguration...
This is the first article providing robust exact finite-time observation, identification and fault detection of linear time-invariant systems satisfying the sufficient and necessary conditions of strong observability basing on high-order sliding-modes differentiation.
This paper presents an analytical redundancy approach for fault detection in frequency subbands. The proposed method employs an optimized wavelet packet decomposition tree to band-limit the signals under consideration. Dynamic consistency checks can be carried out within each frequency subband by using models identified from training data. A fault detection example involving a simulated servomechanism...
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