PL
 |
EN
Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 26

Liczba wyników na stronie
first rewind previous Strona / 2 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  fault isolation
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 2 next fast forward last
1
Content available remote Fuzzy diagnostic reasoning that takes into account the uncertainty of the relation between faults and symptoms
100%
Kościelny J. M. , Syfert M.
|
|
nr 1
27-35
EN
Knowledge about the relation between faults and the observed symptoms is necessary for fault isolation. Such a relation can be expressed in various forms, including binary diagnostic matrices or information systems. The paper presents the use of fuzzy logic for diagnostic reasoning. This method enables us to take into account various kinds of uncertainties connected with diagnostic reasoning, including the uncertainty of the faults-symptoms relation. The presented methods allow us to determine the fault certainty factor as well as certainty factors of the normal and unknown process states. The unknown process state factor groups all the states with unknown and multiple faults with the states with improper residual values, while the normal state factor indicates similarity between the observed state and the pattern fault-free state.
2
Content available remote Fault diagnosis of a water for injection system using enhanced structural isolation
100%
Laursen M. , Blanke M. , Düştegör D.
|
|
nr 4
593-603
EN
A water for injection system supplies chilled sterile water as a solvent for pharmaceutical products. There are ultimate requirements for the quality of the sterile water, and the consequence of a fault in temperature or in flow control within the process may cause a loss of one or more batches of the production. Early diagnosis of faults is hence of considerable interest for this process. This study investigates the properties of multiple matchings with respect to isolability, and it suggests to explore the topologies of multiple use-modes for the process and to employ active techniques for fault isolation to enhance structural isolability of faults. The suggested methods are validated on a high-fidelity simulation of the process.
3
Zastowanie grafu GP w diagnostyce procesów przemysłowych
75%
Ostasz A. , Kościelny J. M.
|
|
tom R. 51, nr 9 bis
51--53
PL
Praca zawiera opis formalny grafu GP, a także dyskusje, o jego podstawowych zastosowaniach. Graf GP jest jakościowym modelem diagnozowanego procesu. Wyraża on zależności przyczynowo-skutkowe pomiędzy zmiennymi stanu, sterującymi i pomiarami, uwzględniając także wpływ uszkodzeń na te zmienne. Jako przykład przedstawiono graf GP dla stanowiska laboratoryjnego trzech zbiorników. Podstawowym zastosowaniem grafu jest: wykorzystanie go do projektowania struktury modeli do detekcji uszkodzeń oraz określania relacji uszkodzenia-symptomy.
EN
The paper considers application of causal graph to description of diagnosed process. Presented graph, called Graph of Process (GP), is a qualitative model of the diagnosed process with respect to faults. The graph is used for designing the model structures for fault detection and identifying of fault - symptom relations. Theoretic background of graph GP has been presented as well as an example based on three tank system.
4
Content available remote Fuzzy-Logic Fault Isolation in Large-Scale Systems
75%
Kościelny J. M. , Sędziak D. , Zakroczymski K.
|
|
tom Vol. 9, no 3
637-652
EN
Application of fuzzy logic in fault isolation is proposed. The introduced methods assume the industrial requirements such as integration of different detection algorithms, system complexity, data and knowledge uncertainties. Algorithms of decreasing the calculation expenditures for diagnosing large-scale systems are also introduced. An example of the application is also shown. The proposed technique is a development of the Dynamic State Tables method.
5
Content available remote Automatyzacja sieci rozdzielczych jako podstawowy element sieci inteligentnych
75%
Babś A.
|
2013
|
tom Vol. 4, Nr 2(12)
22-29
PL
W artykule przedstawiono podstawowe cechy sieci inteligentnych oraz te cechy które powodują, że tradycyjna sieć rozdzielcza może mieć charakter sieci inteligentnej. Szczegółowo przedstawiono dwie funkcje inteligentnych sieci rozdzielczych tj. wykrywanie zwarć, ich izolacja i przywracanie zasilania oraz funkcję regulacji napięcia wykorzystującą pomiary napięć w głębi sieci. Opisano również wymagania jakie powinna spełniać infrastruktura telekomunikacyjna, aby umożliwić realizacje funkcji sieci inteligentnych. Przedstawiono przykład wdrożenia sieci inteligentnej na Półwyspie Helskim opisując wdrożone w 2012 roku funkcje.
EN
Paper presents the basic features of the distribution smart grid. Fault detection, isolation and restoration function is described along with integrated volt/var control function based on the low voltage network measurements. Some requirements related with telecommunication infrastructure utilized for smart grid automation are specified. Practical example of the smart grid functions deployment is described.
6
Content available Uogólniona metoda wnioskowania o uszkodzeniach na podstawie binarnej macierzy diagnostycznej
75%
Bartyś M.
|
|
tom R. 57, nr 7
779-783
PL
W artykule wprowadzono i zdefiniowano pojęcia sygnatur alternatywnych i dominujących. Wprowadzenie tych pojęć pozwoliło na sformalizowanie i uogólnienie schematu wnioskowania o uszkodzeniach obejmującego zarówno podejścia bazujące na binarnej macierzy diagnostycznej jak i podejścia bazujące na podstawie dwuwartościowego systemu informacyjnego FIS. Przedstawiono przykład ilustrujący uogólniony schemat wnioskowania. W podsumowaniu przedstawiono kierunki dalszych prac.
EN
A brief survey of diagnostic fault isolation methods based on a binary diagnostic matrix and bi-valued FIS [3] information system is presented in the introductory part (Section 1) of the paper. It is shown on an example of carcinoma renis disease (Tab.2), that the classic reasoning scheme about single faults based on a binary diagnostic matrix is insufficient and should be revised. It is also shown that the problems of proper reasoning remain unsolved even if the Fault Information System - FIS will be applied. In both cases, there is possible to reject true diagnosis as well as generate a false one. To solve the problem, there were introduced and defined the so called: alternative (10) and dominant signatures (11). Introduction of these signatures enables formal generalisation and extension of the inference scheme about faults (16) including approaches based on a binary diagnostic matrix as well as bi-valued FIS. The advantages of introducing the dominant signatures are described in Section 5. Also, some hints for implementation of the general reasoning scheme are formulated in Section 5. The proposed general reasoning method is useful for applications to system with embedded diagnostics, particularly to those making use of on-line serial and parallel diagnostics [6]. The future works are outlined in the summary (Section 6), including generalization of the inference scheme based on multi-valued FIS and fuzzy evaluation of diagnostic signals.
7
Content available A double window state observer for detection and isolation of abrupt changes in parameters
63%
Byrski J. , Byrski W.
|
2016
|
tom Vol. 26, no. 3
585--602
EN
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 zT (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 tA = 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.
8
Content available remote Wybrane problemy diagnostyki procesów przemysłowych
63%
Kościelny J. M. , Syfert M.
|
|
tom Vol. 53, nr 7
65-79
PL
W referacie omówiono problemy praktyczne, występujące w diagnostyce procesów przemysłowych. Należą do nich: trudności z uzyskaniem odpowiednio wysokiej rozróżnialności uszkodzeń, niepewności występujące we wnioskowaniu diagnostycznym, złożoność struktury obiektu i jej zmienność w trakcie eksploatacji, dynamika powstawania symptomów oraz występowanie uszkodzeń wielokrotnych. Podano sposoby rozwiązania tych problemów. Zostały one zastosowane w opracowanym w Instytucie Automatyki i Robotyki Politechniki Warszawskiej systemie diagnostycznym realizowanym w ramach projektu CHEM.
EN
In the paper the practical issues of diagnostics of industrial processes are described. Here, to the most frequently problems are belonging: difficulties with achievement of sufficiently high fault insolubility, uncertainties of diagnostic reasoning, complexity of the structure of industrial systems and its changeability during exploitation, symptom dynamics as well as occurrence of the multiple faults. The methods of overcoming of those problems are given. Methods presented, were developed in the Institute of Automatic ControI and Robotics of Warsaw University of Technology and have been applied in the diagnostic system developed in the frames of the CHEM project.
9
Content available Fault detection and isolation for dynamic processes using recurrent neural networks
63%
Przystałka P.
Diagnostyka
|
2009
|
tom nr 1(49)
33-40
EN
The paper focuses on the problem of fault detection and isolation for dynamic processes using selected recurrent neural networks. The main objective is to show how to employ some discoveries of the chaos theory for modeling processes by means of globally and locally recurrent neural networks. Both types of neural models are used in fault detection and isolation block. The performance of the FDI system is examined using two types of neural models: Jordan/Elman tower neural networks and networks with dynamic neural units. The paper contains numerical examples that illustrate the merits and limits of these two approaches.
PL
Treść artykuł wiąże się z problemem detekcji i lokalizacji uszkodzeń dla szerokiej gamy procesów dynamicznych z użyciem wybranych rekurencyjnych sieci neuronowych. Głównym celem jest pokazanie w jaki sposób mogą zostać zastosowane niektóre z odkryć teorii chaosu do modelowania procesów z użyciem globalnych i lokalnych struktur neuronowych. Oba typy modeli neuronowych zostały użyte w bloku detekcji i lokalizacji uszkodzeń. Sprawność układu diagnostycznego porównana została dla modeli procesów z zastosowaniem: sieci wielo-kontekstowych Jordana/Elmana i sieci z neuronami dynamicznymi. W artykule zamieszczono przykłady numeryczne wskazujące na zalety i wady obu podejść.
10
Content available Residual generator fuzzy identification for automotive diesel engine fault diagnosis
63%
Simani S.
|
|
tom Vol. 23, no. 2
419--438
EN
Safety in dynamic processes is a concern of rising importance, especially if people would be endangered by serious system failure. Moreover, as the control devices which are now exploited to improve the overall performance of processes include both sophisticated control strategies and complex hardware (input-output sensors, actuators, components and processing units), there is an increased probability of faults. As a direct consequence of this, automatic supervision systems should be taken into account to diagnose malfunctions as early as possible. One of the most promising methods for solving this problem relies on the analytical redundancy approach, in which residual signals are generated. If a fault occurs, these residual signals are used to diagnose the malfunction. This paper is focused on fuzzy identification oriented to the design of a bank of fuzzy estimators for fault detection and isolation. The problem is treated in its different aspects covering the model structure, the parameter identification method, the residual generation technique, and the fault diagnosis strategy. The case study of a real diesel engine is considered in order to demonstrate the effectiveness the proposed methodology.
11
Content available remote Fault diagnosis of a water for injection system using enhanced structural isolation
63%
Laursen M. , Blanke M. , Düştegör D.
|
|
tom Vol. 18, no 4
593-603
EN
A water for injection system supplies chilled sterile water as a solvent for pharmaceutical products. There are ultimate requirements for the quality of the sterile water, and the consequence of a fault in temperature or in flow control within the process may cause a loss of one or more batches of the production. Early diagnosis of faults is hence of considerable interest for this process. This study investigates the properties of multiple matchings with respect to isolability, and it suggests to explore the topologies of multiple use-modes for the process and to employ active techniques for fault isolation to enhance structural isolability of faults. The suggested methods are validated on a high-fidelity simulation of the process.
12
Content available Algorytm minimalizacji sygnatur uszkodzeń
63%
Chalecki D.
|
|
tom nr 3(39)
297-300
PL
W pracy przedstawiono metodę minimalizacji sygnatur uszkodzeń jako jedno z rozwiązań problemów związanych z dużą liczbą sygnałów pomiarowych, wykorzystywanych testów i potencjalnych uszkodzeń w złożonych instalacjach technologicznych. Jego opracowanie ma na celu skrócenie czasu lokalizacji uszkodzeń w takich instalacjach. W referacie opisano różnicę pomiędzy pełnymi sygnaturami uszkodzeń a sygnaturami zredukowanymi oraz przedstawiono poszczególne kroki realizacji algorytmu, na podstawie którego można uzyskać sygnatury zredukowane.
EN
The paper presents a method of minimization of fault signatures as a solution of a problem concerning large number of measuring signals and potential faults in compound technological systems. The aim of elaboration of the algorithm is to shorten the time of fault isolation in such systems. The paper describes the difference between full and reduced fault signatures as well as presents individual steps of realization of the algorithm enabling to obtain the reduced signatures.
13
Content available remote Fuzzy diagnostic reasoning that takes into account the uncertainty of the relation between faults and symptoms
63%
Kościelny J. M. , Syfert M.
|
2006
|
tom Vol. 16, no 1
27-35
EN
Knowledge about the relation between faults and the observed symptoms is necessary for fault isolation. Such a relation can be expressed in various forms, including binary diagnostic matrices or information systems. The paper presents the use of fuzzy logic for diagnostic reasoning. This method enables us to take into account various kinds of uncertainties connected with diagnostic reasoning, including the uncertainty of the faults-symptoms relation. The presented methods allow us to determine the fault certainty factor as well as certainty factors of the normal and unknown process states. The unknown process state factor groups all the states with unknown and multiple faults with the states with improper residual values, while the normal state factor indicates similarity between the observed state and the pattern fault-free state.
14
Content available remote Parameter Estimation Based Fault Detection and Isolation in Wiener and Hammerstein Systems
63%
Janczak A.
|
|
tom Vol. 9, no 3
711-735
EN
Fault detection and isolation in Wiener and Hammerstein systems via generation and processing of residual sequences is considered. We assume that some models of the unfaulty Wiener and Hammerstein systems under consideration are known. For Wiener systems, we also assume that their static nonlinear subsystems are invertible. Then, based on a serial-parallel definition of the residual error, new fault detection and isolation methods are proposed.To detect and identify all the changes in both the Wiener and Hammerstein system parameters, the sequences of residuals are processed by using linear regression methods or a neural network approach.
15
Content available Generalized reasoning about faults based on the diagnostic matrix
63%
Bartyś M.
|
|
tom Vol. 23, no. 2
407--417
EN
This paper introduces a set of comprehensive general reasoning rules about single faults based on a diagnostic matrix. The reasoning scheme unifies inference about faults based on a conventional binary diagnostic matrix, a two- and three-valued fault isolation system as well as on their fuzzy counterparts. There are introduced and defined notions of alternative and dominant fault signatures, fuzzy fault signatures as well as a matrix of alternative signatures. This matrix is supposed to be used instead of the classic diagnostic one. It is also shown that dominant fault signatures are transformable into alternative ones. Finally, three variants of concise general reasoning rules of faults are given. Three examples illustrate key point issues of the paper. The first example refers to a medical diagnostic case. It shows an instance of dominant fault signatures and, in fact, proposes a rational approach for planning diagnostic tests. The other examples describe the fuzzy reasoning approach employing a matrix of fuzzy alternative signatures applicable for use with multi-valued fuzzy diagnostic signals. Future works are outlined in the summary section.
16
Content available Rozróżnialność uszkodzeń w układach liniowych
63%
Kościelny J. M. , Dziembowski B.
|
|
tom nr 2(38)
93-100
PL
W referacie przedstawiono różne metody zapisu związku między uszkodzeniami i wartościami sygnałów diagnostycznych dla obiektów diagnozowania opisywanych modelami liniowymi. Przeprowadzono analizę porównawczą rozróżnialności uszkodzeń uzyskiwanej z zastosowaniem prezentowanych metod. Omówiono nową metodę zwiększania rozróżnialności uszkodzeń bazującą na sekwencji pojawiających się symptomów. Przedyskutowano zalety i ograniczenia poszczególnych metod.
EN
Different methods of describing relations between faults and values of diagnostic signals for systems with linear models are presented in this paper. Realize there comparative analysis of faults distinguishability using presented methods. Talk over new method of fault's distinguishability increase based on sequence of emerge symptoms. Discuss advantages and constraint each presented methods.
17
Content available remote Fault detection and isolation with robust principal component analysis
51%
Tharrault Y. , Mourot G. , Ragot J. , Maquin D.
|
|
tom Vol. 18, no 4
429-442
EN
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.
18
Content available remote Input reconstruction by means of system inversion: A geometric approach to fault detection and isolation in nonlinear systems
51%
Edelmayer A. , Bokor J. , Szabo Z. , Szigeti F.
|
2004
|
tom Vol. 14, no 2
189-199
EN
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.
19
Content available Fault tolerant control of wind turbine via identified fuzzy models prototypes
51%
Djoudi H. C. B. , Hafaifa A. , Djoudi D. , Guemana M.
|
|
tom Vol. 21, No. 3
3--13
EN
The main purpose of this study is the comparison of two control strategies of wind turbine 4.8 MW, using fuzzy control and proportional integral control, taking into account eight kinds of faults that can occur in a wind turbine model. A technique based on fault diagnosis has been used to detect and isolate faults actuators and sensors in this system, it's about an observer applied to the benchmark model. The obtained results are presented to validate the effectiveness of this diagnostic method and present the results of the proposed control strategies.
20
Content available Switching time estimation and active mode recognition using a data projection method
51%
Hakem A. , Cocquempot V. , Pekpe K. M.
|
|
tom Vol. 26, no. 4
827--840
EN
This paper proposes a data projection method (DPM) to detect a mode switching and recognize the current mode in a switching system. The main feature of this method is that the precise knowledge of the system model, i.e., the parameter values, is not needed. One direct application of this technique is fault detection and identification (FDI) when a fault produces a change in the system dynamics. Mode detection and recognition correspond to fault detection and identification, and switching time estimation to fault occurrence time estimation. The general principle of the DPM is to generate mode indicators, namely, residuals, using matrix projection techniques, where matrices are composed of input and output measured data. The DPM is presented in detail, and properties of switching detectability (fault detectability) and discernability between modes (fault identifiability) are characterized and discussed. The great advantage of this method, compared with other techniques in the literature, is that it does not need the model parameter values and thus can be applied to systems of the same type without identifying their parameters. This is particularly interesting in the design of generic embedded fault diagnosis algorithms.
first rewind previous Strona / 2 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.