Temat: fault reconstruction

Skocz do pozycji: 1.

Tytuł:: An H∞ sliding mode observer for Takagi–Sugeno nonlinear systems with simultaneous actuator and sensor faults
Autorzy:: Ben Brahim, A.
Dhahri, S.
Ben Hmida, F.
Sellami, A.
Tematy:: fault reconstruction
fault estimation
simultaneous fault
H∞ sliding mode observer
uncertain Takagi Sugeno system
LMI optimization; Pokaż więcej
Wydawca:: Uniwersytet Zielonogórski. Oficyna Wydawnicza
Powiązania:: https://bibliotekanauki.pl/articles/330626.pdf Link otwiera się w nowym oknie
Opis:: This paper considers the problem of robust reconstruction of simultaneous actuator and sensor faults for a class of uncertain Takagi–Sugeno nonlinear systems with unmeasurable premise variables. The proposed fault reconstruction and estimation design method with H∞ performance is used to reconstruct both actuator and sensor faults when the latter are transformed into pseudo-actuator faults by introducing a simple filter. The main contribution is to develop a sliding mode observer (SMO) with two discontinuous terms to solve the problem of simultaneous faults. Sufficient stability conditions in terms linear matrix inequalities are achieved to guarantee the stability of the state estimation error. The observer gains are obtained by solving a convex multiobjective optimization problem. Simulation examples are given to illustrate the performance of the proposed observer.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Research on topology of a novel three-phase four-leg fault-tolerant NPC inverter
Autorzy:: Zhang, Baoge
Ping, Shanyan
Long, Yyi
Jiao, Yyuemin
Wu, Bboxiang
Tematy:: fault tolerant operation
midpoint potential equilibrium
NPC inverter
topology reconstruction; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/2086722.pdf Link otwiera się w nowym oknie
Opis:: Diode neutral point clamped (NPC) three-level converters have been widely used in recent years. Aiming at the problems of the high device failure rate and unstable neutral point potential of NPC three-level converters, an NPC three-level circuit with fourth bridge arm redundancy is proposed based on the traditional NPC three-level converter. The redundant fourth bridge arm is used to realize the function of stabilizing voltage when there is no fault and replacing the fault half-bridge arm to maintain the continuous operation of the converter when there is a fault. By analyzing the working principle of space vector pulse width modulation (SVPWM) and the power loss of the switch, it is of particular significance to the design and control of NPC three-level converters in the future. Matlab/Simulink verifies the feasibility of the fault-tolerant circuit structure.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Model predictive control of NPC three-level grid-tied converter based on reconstructed current
Autorzy:: Li, Yanyan
Xiao, Han
Jin, Nan
Yan, Guanglu
Tematy:: current reconstruction
current sensor fault
fault-tolerant
model predictive control
neutral point clamped three-level converter; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/2086686.pdf Link otwiera się w nowym oknie
Opis:: The neutral point clamped (NPC) three-level grid-tied converter is the key equipment connecting renewable energy and power grids. The current sensor fault caused by harsh environment may lead to the split of renewable energy. The existing sensor fault-tolerant methods will reduce the modulation ratio index of the converter system. To ensure continuous operation of the converter system and improve the modulation index, a model predictive control method based on reconstructed current is proposed in this paper. According to the relationship between fault phase current and a voltage vector, the original voltage vector is combined and classified. To maintain the stable operation of the converter and improve the utilization rate of DC voltage, two kinds of fault phase current are reconstructed with DC current, normal phase current and predicted current, respectively. Based on reconstructed three-phase current, a current predictive control model is designed, and a model predictive control method is proposed. The proposed method selects the optimal voltage vector with the cost function and reduces time delay with the current reconstruction sector. The simulation and experimental results show that the proposed strategy can keep the NPC converter running stably with one AC sensor, and the modulation index is increased from 57.7% to 100%.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Input reconstruction by means of system inversion: A geometric approach to fault detection and isolation in nonlinear systems
Autorzy:: Edelmayer, A.
Bokor, J.
Szabo, Z.
Szigeti, F.
Tematy:: detekcja uszkodzeń
lokalizacja uszkodzeń
układ liniowy
układ nieliniowy
inwersja systemu
fault detection
fault isolation
input reconstruction
linear system
nonlinear system
system inversion; Pokaż więcej
Wydawca:: Uniwersytet Zielonogórski. Oficyna Wydawnicza
Powiązania:: https://bibliotekanauki.pl/articles/907385.pdf Link otwiera się w nowym oknie
Opis:: In this paper the classical detection filter design problem is considered as an input reconstruction problem. Input reconstruction is viewed as a dynamic inversion problem. This approach is based on the existence of the left inverse and arrives at detector architectures whose outputs are the fault signals while the inputs are the measured system inputs and outputs and possibly their time derivatives. The paper gives a brief summary of the properties and existence of the inverse for linear and nonlinear multivariable systems. A view of the inversion-based input reconstruction with special emphasis on the aspects of fault detection and isolation by using invariant subspaces and the results of classical geometrical systems theory is provided. The applicability of the idea to fault reconstruction is demonstrated through examples.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Fault detection and isolation with robust principal component analysis
Autorzy:: Tharrault, Y.
Mourot, G.
Ragot, J.
Maquin, D.
Tematy:: analiza głównych składowych
odporność
detekcja uszkodzeń
lokalizacja uszkodzeń
principal component analysis
robustness
outliers
fault detection
fault isolation
structured residual vector
variable reconstruction; Pokaż więcej
Wydawca:: Uniwersytet Zielonogórski. Oficyna Wydawnicza
Powiązania:: https://bibliotekanauki.pl/articles/929927.pdf Link otwiera się w nowym oknie
Opis:: 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 is applied to remove the effect of outliers on the PCA model. In this paper, a fast two-step algorithm is proposed. First, the objective was to find an accurate estimate of the covariance matrix of the data so that a PCA model might be developed that could then be used for fault detection and isolation. A very simple estimate derived from a one-step weighted variance-covariance estimate is used (Ruiz-Gazen, 1996). This is a 'local' matrix of variance which tends to emphasize the contribution of close observations in comparison with distant observations (outliers). Second, structured residuals are used for multiple fault detection and isolation. These structured residuals are based on the reconstruction principle, and the existence condition of such residuals is used to determine the detectable faults and the isolable faults. The proposed scheme avoids the combinatorial explosion of faulty scenarios related to multiple faults to be considered. Then, this procedure for outliers detection and isolation is successfully applied to an example with multiple faults.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Reconstruction-based stacked sparse auto-encoder for nonlinear industrial process fault diagnosis
Autorzy:: Weng, Qihang
Ren, Shaojun
Zhu, Baoyu
Jin, Yinfeng
Si, Fengqi
Tematy:: process monitoring
fault diagnosis
stacked sparse auto-encoder
reconstruction-based method
sequential floating forward selection; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Powiązania:: https://bibliotekanauki.pl/articles/59112850.pdf Link otwiera się w nowym oknie
Opis:: The reconstruction-based (RB) approach can effectively suppress the misdiagnosis problem due to the smearing effect in fault isolation. However, the current exploration of the RB approach for large-scale nonlinear systems is still limited. Therefore, this paper proposes a reliable and effective fault diagnosis method based on a reconstruction-based stacked sparse autoencoder (RBSSAE) for high-dimensional industrial systems. In RBSSAE, a reconstruction-based index achieved by the Steffensen iterative method is developed to check whether the given variable(s) are responsible for the faults efficiently. However, the number of possible faulty variable combinations grows exponentially with the system dimensionor actual abnormal variables, causing an unbearable computational burden for variable combination optimization. Hence, the proposed RBSSAE utilizes a sequential floating forward selection approach to rapidly isolate the most decisive combination of fault variables, meeting a requirement of online fault diagnosis. Finally, the effectiveness of the RBSSAE is verified on a numerical example and a real industrial case. Comparisons with other state-of-the-art methods are also presented.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: A double window state observer for detection and isolation of abrupt changes in parameters
Autorzy:: Byrski, J.
Byrski, W.
Tematy:: fault detection
fault isolation
exact state observer
parameter abrupt changes
derivative reconstruction
linear continuous system
detekcja uszkodzeń
lokalizacja uszkodzeń
dokładny obserwator stanu
układ ciągły liniowy; Pokaż więcej
Wydawca:: Uniwersytet Zielonogórski. Oficyna Wydawnicza
Powiązania:: https://bibliotekanauki.pl/articles/330142.pdf Link otwiera się w nowym oknie
Opis:: The paper presents a new method for diagnosis of a process fault which takes the form of an abrupt change in some real parameter of a time-continuous linear system. The abrupt fault in the process real parameter is reflected in step changes in many parameters of the input/output model as well as in step changes in canonical state variables of the system. Detection of these state changes will enable localization of the faulty parameter in the system. For detecting state changes, a special type of exact state observer will be used. The canonical state will be represented by the derivatives of the measured output signal. Hence the exact state observer will play the role of virtual sensors for reconstruction of the derivatives of the output signal. For designing the exact state observer, the model parameters before and after the moment of fault occurrence must be known. To this end, a special identification method with modulating functions will be used. A novel concept presented in this paper concerns the structure of the observer. It will take the form of a double moving window observer which consists of two signal processing windows, each of width T . These windows are coupled to each other with a common edge. The right-hand side edge of the left-side moving window in the interval [t − 2T, t − T ] is connected to the left-hand side edge of the right-side window which operates in the interval [t − T, t]. The double observer uses different measurements of input/output signals in both the windows, and for each current time t simultaneously reconstructs two values of the state—the final value of the state in the left-side window z_T (t − T ) and the initial value of the state z₀(t − T ) in the right-side window. If the process parameters are constant, the values of both the states on the common joint edge are the same. If an abrupt change (fault) in some parameter at the moment t_A = t − T occurs in the system, then step changes in some variables of the canonical state vector will also occur and the difference between the states will be detected. This will enable localization of the faulty parameter in the system.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Pozycja tektoniczna Roztocza w świetle historii rozwoju zapadliska przedkarpackiego
Tectonic position of the Roztocze region in the light of the evolution history of the Carpathian Foredeep
Autorzy:: Jankowski, L.
Margielewski, W.
Tematy:: rekonstrukcja tektoniczna
uskok przesuwczy
struktura kwiatowa
wypiętrzenie przedgórskie
Roztocze Środkowe i Południowe
południowo-wschodnia Polska
tectonic reconstruction
strike-slip fault
flower structure
forebulge structure
Middle and Southern Roztocze region
south-east Poland; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2061934.pdf Link otwiera się w nowym oknie
Opis:: Analizy tektoniczne wykonane na podstawie pomiarów powierzchni nieciągłości tektonicznych w obrębie masywów skalnych polskiej części Roztocza, pozwoliły na odtworzenie historii tektonicznej jego struktury, związanej z tworzeniem się zapadliska przedkarpackiego i etapami nasuwczymi Karpat. Analizy wykazały, że struktura Roztocza powstała w efekcie nakładania się asocjacji struktur tektonicznych związanych z formowaniem uskoku prawoprzesuwczego (tzw. struktury kwiatowe ‒ flower structures i struktury typu koński ogon – horse tail structure) i struktury forebulge związanej z wypiętrzeniem przedgórskim spowodowanym nasuwaniem się Karpat na przedpole (tu: zapadlisko przedkarpackie). Wielokrotne reaktywowanie stref dyslokacyjnych, obramowujących Roztocze i dzielących je na bloki, było efektem formowania się uskoków inwersyjnych (związanych ze strukturą forebulge), reaktywowanych później wskutek kolapsu jako uskoki normalne. Zmiana zwrotu uskoku przesuwczego ograniczającego Roztocze na sinistralny, była efektem reorientacji pola naprężeń spowodowanej zmianą kierunku nasuwczego Karpat ku SSE. Spowodowało to inwersję stref naprzemiennie obniżanych i wynoszonych wzdłuż krawędzi Roztocza: obecnie wynoszone są obszary z niezerodowanymi, miąższami pokrywami utworów neogeńskich, obniżane zaś fragmenty strefy krawędziowej erozyjnie pozbawione tych utworów. Współcześnie obserwowane dźwiganie neotektoniczne Roztocza jest efektem footwall elevation, związanej z zespołami aktywnych uskoków zrzutowych (normalnych), ograniczających strukturę zrębową Roztocza, jak też dzielących wał na bloki.
The paper presents new concept of the tectonic development of the Roztocze region, uplifted as a tectonic horst structure. Measurements of tectonic discontinuities (joints, faults) in the rocks building the Roztocze region, as well as the analysis of Neogene deposits distribution on the Roztocze horst, have allowed authors to establish several tectonic stages of the Roztocze development. Thrusting of the Carpathians to the north caused the formation of a strike-slip (dextral) fault along the eastern part of their foredeep (and associated flower structures and horse tail structures). As a result of forebulge structure formation, caused by progressive thrusting of the Carpathian orogen and isostatic uplift of their foreland, strike-slip faults were reactivated as reverse-slip faults. Subsequently, due to collapse of the Carpathian massifs, discontinuities were again reactivated as dip-slip faults. The footwall elevation associated with normal faults formed into the Roztocze Horst and divided region to blocks, causing a neotectonic uplift of the Roztocze region.
Dostawca treści:: Biblioteka Nauki

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