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    Wyświetlanie 1-6 z 6
    Tytuł:
    Fabrication of a test rig for gearbox fault simulation and diagnosis
    Autorzy:
    Dubaish, Asaad Abdulhussein
    Jaber, Alaa Abdulhady
    Powiązania:
    https://bibliotekanauki.pl/articles/2203635.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
    Tematy:
    fault detection
    vibration analysis
    time-domain signal
    gearbox
    LabVIEW
    wykrywanie uszkodzeń
    analiza drgań
    przekładnia
    Opis:
    Gearboxes are one of the most important and widely exposed to different types of faults in machines. Therefore, manufacturers and researchers have made significant efforts to develop different fault detection and diagnostic approaches for gearboxes. However, many research foundations, such as universities, are currently working on developing different gearbox test rigs to understand the failure mechanisms in gearboxes. As a result, in this article, a gearbox testing rig was proposed and fabricated to evaluate gear performance under lowspeed working conditions. It describes the primary mechanical apparatus and the measurement tools used during the experimental analysis of a multistage gearbox transmission system. The data-gathering equipment used to acquire the observed vibration data is also discussed. LabVIEW software was used to build a data acquisition platform using an accelerometer and a NI DAQ device. Then different vibration tests were conducted under different operating conditions, when the gearbox was healthy and then faulty, on this test rig, and the gathered vibration data were analyzed based on time domain signal analysis. The preliminary results are promising and open the horizon for simulating different gearbox test scenarios.
    Źródło:
    Diagnostyka; 2023, 24, 2; art. no. 2023204
    1641-6414
    2449-5220
    Pojawia się w:
    Diagnostyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zaawansowane metody analiz w pomiarach jakości energii elektrycznej
    Advanced signal analysis methods in power quality measurements
    Autorzy:
    Górecki, K.
    Szmajda, M.
    Zygarlicki, J.
    Zygarlicka, M.
    Mroczka, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/157311.pdf
    Data publikacji:
    2011
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    jakość energii elektrycznej
    częstotliwościowe analizy sygnałów
    czasowo-częstotliwościowe analizy sygnałów
    power quality
    frequency domain signal analysis
    time-frequency domain signal analysis
    Opis:
    W artykule przedstawiono problematykę pomiarów jakości energii elektrycznej oraz zaprezentowano najważniejsze metody analizy zakłóceń występujących w sieciach elektroenergetycznych, jakie rozwijane są w zespole zajmującym się jakością energii elektrycznej w Instytucie Automatyki i Informatyki Politechniki Opolskiej. Przedstawiono systematykę metod analiz sygnałów oraz określono metody wykorzystywane obecnie w pomiarach sygnałów elektrycznych. Ponadto zaprezentowano metody alternatywne do transformacji Fouriera umożliwiające precyzyjną analizę częstotliwościową (analiza Prony'ego) oraz lokalizację zakłóceń za pomocą metod czasowo-częstotliwościowych (transformacja Falkowa, dyskretna transformacja Falkowa, dystrybucja Wignera-Ville'a i jej odmiany, transformacja Gabora-Wignera).
    The issue of measuring power quality parameters and the most important analyses of disturbances occurring in the power network are presented in the paper. These subjects are developed by a power quality and signal analysis group, working at the Faculty of Electrical Engineering, Automatic Control and Informatics. The basic classification of signal analysis methods is given in the paper (Fig. 1). Moreover, the methods currently used in power quality measurement systems are described. In most cases the analyses are based on Fourier Transformation [2-4]. The methods, due to 10-cycles measurement period, cause significant computational errors in case of existence of short duration harmonics in a signal. Moreover, very precise synchronization of the sampling frequency and real power wave-form frequency is needed. Therefore other kinds of analyses in power quality measurement systems are currently investigated. The alternative to Fourier Transformation methods allowing precise estimation of the signal spectrum is Prony analysis [5]. The analysis enables extracting frequency components on the basis of a much shorter measurement window than FFT [6-10]. For localizing the power disturbances, linear (Short-Time Fourier analysis STFT, Gabor Transform GT [12, 13], Wavelet Transform [14, 15, 16]) and bilinear (Wigner-Ville WVD, Pseudo-WVD [17,18]) time-frequency analyses are performed. The combination of both groups of methods (Gabor-Wigner Transform GWT [19,20]) is also presented in the paper. Application of image processing algorithms [21, 22] is also considered in the paper.
    Źródło:
    Pomiary Automatyka Kontrola; 2011, R. 57, nr 3, 3; 284-286
    0032-4140
    Pojawia się w:
    Pomiary Automatyka Kontrola
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Problem of Aliasing and Folding Effects in Spectrum of Sampled Signals in View of Information Theory
    Autorzy:
    Borys, Andrzej
    Powiązania:
    https://bibliotekanauki.pl/articles/2055264.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    signal sampling
    modeling of sampled signal in the time domain
    signal information content
    spectrum aliasing and folding
    Banach–Tarski-like paradox in signal sampling
    Opis:
    In this paper, the problem of aliasing and folding effects in spectrum of sampled signals in view of Information Theory is discussed. To this end, the information content of deterministic continuous time signals, which are continuous functions, is formulated first. Then, this notion is extended to the sampled versions of these signals. In connection with it, new signal objects that are partly functions but partly not are introduced. It is shown that they allow to interpret correctly what the Whittaker–Shannon reconstruction formula in fact does. With help of this tool, the spectrum of the sampled signal is correctly calculated. The result achieved demonstrates that no aliasing and folding effects occur in the latter. Finally, it is shown that a Banach–Tarski-like paradox can be observed on the occasion of signal sampling.
    Źródło:
    International Journal of Electronics and Telecommunications; 2022, 68, 2; 315--322
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An analysis of Chosen Image Formation Algorithms for Synthetic Aperture Radar with FMCW
    Autorzy:
    Okoń-Fąfara, M.
    Serafin, P.
    Kawalec, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/227061.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    signal processing
    synthetic aperture radar
    time domain correlation
    range-Doppler algorithm
    range migration algorithm
    Opis:
    The modelling of FMCW SAR systems, due to long signal duration time, commonly used start-stop approximation for pulsed radars causes errors in the image. Continuous motion of the radar platform results in additional range-azimuth couplings and range walk term that should be considered in processing of signal from this type of radar. The paper presents an analysis of the following algorithms: Time Domain Correlation (TDC), Range Doppler Algorithm (RDA), and Range Migration Algorithm (RMA). The comparison of the algorithms is based on theoretical estimation of their computation complexity and the quality of images obtained on the basis of real signals of FMCW SAR systems.
    Źródło:
    International Journal of Electronics and Telecommunications; 2016, 62, 4; 323-328
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Identification of inability states of rotating subsystems of vehicles and machines
    Autorzy:
    Pająk, Michał
    Lisjak, Dragutin
    Kolar, Davor
    Powiązania:
    https://bibliotekanauki.pl/articles/244261.pdf
    Data publikacji:
    2019
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    rotating system
    technical state
    inability state
    ability state
    vibration signal
    diagnostics
    time domain analyse
    Opis:
    One of the most important subsystems of the vehicles and machines operating currently in industry and transportation are the rotating subsystems. During the subsystems operation, due to the forcing factors influence, the technical state of them is changing and the failure can occur. In order to avoid such a situation the technical state should be identified online. To do this the analysis of the subsystems vibrations is performed. The identified technical state should be considered in a context of the ability and different inability states. Therefore, the first step of the diagnostic procedure is the ability and different inability states identification. In the article, it is proposed to accomplish this goal by the vibrations analysis in time domain. The described research started with the vibration signals acquisition using the experimental stand. In this way, the vibration signals for ability and different inability states were obtained. Afterwards, the signals were divided into learning and testing data sets. For each signal from learning data set, several characteristics were calculated, and they selected the most significant among them. Using the selected characteristics, the signals from the testing data set were analysed. Thanks to it, the testing vibrations signals were counted among the signals collected on the rotating subsystem operating in ability or selected inability state. The result of the performed studies and the accuracy of the technical state of the tested system identification can be found at the end of the article.
    Źródło:
    Journal of KONES; 2019, 26, 1; 111-118
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Applications and Comparison of Continuous Wavelet Transforms on Analysis of A-wave Impulse Noise
    Autorzy:
    Qin, J.
    Sun, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/177117.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    continuous wavelet transform (CWT)
    impulse noise signal processing
    time-frequency domain
    temporal and spectral resolutions
    noise-induced hearing loss
    A-wave impulse noise
    Opis:
    Noise induced hearing loss (NIHL) is a serious occupational related health problem worldwide. The A-wave impulse noise could cause severe hearing loss, and characteristics of such kind of impulse noise in the joint time-frequency (T-F) domain are critical for evaluation of auditory hazard level. This study focuses on the analysis of A-wave impulse noise in the T-F domain using continual wavelet transforms. Three different wavelets, referring to Morlet, Mexican hat, and Meyer wavelets, were investigated and compared based on theoretical analysis and applications to experimental generated A-wave impulse noise signals. The underlying theory of continuous wavelet transform was given and the temporal and spectral resolutions were theoretically analyzed. The main results showed that the Mexican hat wavelet demonstrated significant advantages over the Morlet and Meyer wavelets for the characterization and analysis of the A-wave impulse noise. The results of this study provide useful information for applying wavelet transform on signal processing of the A-wave impulse noise.
    Źródło:
    Archives of Acoustics; 2015, 40, 4; 503-512
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-6 z 6

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