Wyniki wyszukiwania - BazTech

1

Discrete wavelet transform and energy distribution for effective bearing fault detection and analysis

Beldjaatit Chahinez, Sebbagh Toufik, Guentri Hocine

Przegląd Elektrotechniczny

|

2023

|

R. 99, nr 7

24--28

EN

Condition monitoring and problem diagnostics have drawn more attention recently in the industrial sector. One of the most crucial parts of rotating machinery are rolling-element bearings. Bearing faults are a common cause of machinery failures. To identify failing bearings early, vibration condition monitoring of rotating machinery has emerged as the preferred technique. Several signal analysis techniques can extract useful information from vibration data. The non-stationary analysis signals that are typically associated with machine defects cannot be handled by frequency-based approaches. Non-stationary signals are analyzed effectively by applying time-frequency techniques. The use of wavelet transform has increased in bearing monitoring research for the last 20 years to obtain correlated time-frequency information. This paper presents a discrete wavelet transform (DWT) and energy distribution-based bearing defect diagnostic technique. The "db3" wavelet form of DWT is used to decompose vibration signals under both normal and faulty (inner race-fault and outer race-fault) bearing conditions at various frequency ranges. Due to the default, the energy distribution for every decomposition level is calculated to detect which frequency band contains the harmonics. The results obtained from healthy and defective bearings are compared. The wavelet coefficient with the highest value of the energy distribution is employed in the Fourier analysis to pinpoint the site of the fault. The monitoring results demonstrate that the suggested approach is effective in finding and analyzing faults.

PL

Monitorowanie stanu i diagnostyka problemów przyciągnęły ostatnio więcej uwagi w sektorze przemysłowym. Jedną z najbardziej kluczowych części maszyn wirujących są łożyska toczne. Usterki łożysk są częstą przyczyną awarii maszyn. W celu wczesnej identyfikacji uszkodzonych łożysk, monitorowanie stanu wibracji maszyn wirujących stało się preferowaną techniką. Kilka technik analizy sygnału może wydobyć użyteczne informacje z danych o drganiach. Niestacjonarne sygnały analizy, które są zwykle związane z uszkodzeniami maszyn, nie mogą być obsługiwane przez podejścia oparte na częstotliwości. Sygnały niestacjonarne są skutecznie analizowane poprzez zastosowanie technik czasowoczęstotliwościowych. Zastosowanie transformaty falkowej wzrosło w badaniach nad monitorowaniem łożysk przez ostatnie 20 lat w celu uzyskania skorelowanej informacji czasowo-częstotliwościowej. W niniejszej pracy przedstawiono dyskretną transformatę falkową (DWT) oraz technikę diagnostyczną opartą na rozkładzie energii. Forma falkowa "db3" DWT jest używana do dekomponowania sygnałów drganiowych w warunkach łożyska zarówno normalnego, jak i wadliwego (wewnętrznego i zewnętrznego) w różnych zakresach częstotliwości. Ze względu na domyślność, rozkład energii dla każdego poziomu dekompozycji jest obliczany w celu wykrycia, które pasmo częstotliwości zawiera harmoniczne. Wyniki uzyskane z łożysk zdrowych i uszkodzonych są porównywane. Współczynnik falkowy o największej wartości rozkładu energii jest wykorzystywany w analizie Fouriera w celu określenia miejsca uszkodzenia. Wyniki monitorowania pokazują, że proponowane podejście jest skuteczne w wyszukiwaniu i analizie uszkodzeń.

2

Diagnosis of ITSC fault in the electrical vehicle powertrain system through signal processing analysis

Ouamara Dehbia, Boukhnifer Moussa, Chaibet Ahmed, Maidi Ahmed

Diagnostyka

|

2023

|

Vol. 24, No. 1

art. no. 2023113

EN

The three-phase induction motor is well suited for a wide range of mobile drives, specifically for electric vehicle powertrain. During the entire life cycle of the electric motor, some types of failures can occur, with stator winding failure being the most common. The impact of this failure must be considered from the incipient as it can affect the performance of the motor, especially for electrically powered vehicle application. In this paper, the intern turn short circuit of the stator winding was studied using Fast Fourier transform (FFT) and Shor-Time Fourier transform (STFT) approaches. The residuals current between the estimated currents provided by the extended Kalman filter (EKF) and the actual ones are used for fault diagnosis and identification. Through FFT, the residual spectrum is sensitive to faults and gives the extraction of inter-turn short circuit (ITSC) related frequencies in the phase winding. In addition, the FFT is used to obtain information about when and where the ITSC appears in the phase winding. Indeed, the results allow to know the faulty phase, to estimate the fault rate and the fault occurrence frequency as well as their appearance time.

3

Infrasound Signal Classification Based on ICA and SVM

Lu Quanbo, Wang Meng, Li Mei

Archives of Acoustics

|

2023

|

Vol. 48, No. 2

191--199

EN

A diagnostic technique based on independent component analysis (ICA), fast Fourier transform (FFT), and support vector machine (SVM) is suggested for effectively extracting signal features in infrasound signal monitoring. Firstly, ICA is proposed to separate the source signals of mixed infrasound sources. Secondly, FFT is used to obtain the feature vectors of infrasound signals. Finally, SVM is used to classify the extracted feature vectors. The approach integrates the advantages of ICA in signal separation and FFT to extract the feature vectors. An experiment is conducted to verify the benefits of the proposed approach. The experiment results demonstrate that the classification accuracy is above 98.52% and the run time is only 2.1 seconds. Therefore, the proposed strategy is beneficial in enhancing geophysical monitoring performance.

4

Using the MIMO method to evaluate the modal properties of the elements of a wheelset in an active experiment

Milewicz Julia, Mokrzan Daniel, Nowakowski Tomasz, Szymański Grzegorz M.

Vibrations in Physical Systems

|

2022

|

Vol. 33, nr 3

art. no. 2022324

EN

The study of the system composed of the inner disc and wheel rim of the 105Na type railway wheel, used in Polish Konstal streetcars, was aimed at determining the dynamic parameters of the object, such as the form and frequency of natural vibrations, and at evaluating the effectiveness of the method at given analysis settings. The experiment was conducted using triaxial piezoelectric transducers and a modal hammer with an aluminum head. A multiple-input, multiple-output (MIMO) testing approach was used because of the multiple excitation points and vibration measurements. A Fast Fourier Transform (FFT) of the measurements was performed in BK Connect software and the frequency response function (FRF) value waveforms were determined. The Rational Fraction Polynomial-Z method was used to extract modes from the frequency spectrum. In addition, the Complex Mode Indicator Function method was used, which resulted in the decomposition of the principal components of the FRF value matrix, allowing the identification of individual modes. The selection of the natural frequencies was performed on the basis of the obtained FRF and CMIF characteristics of the vibroacoustic response. Visualization of the form of the natural vibration was also performed. The result of the experiment was a set of comprehensive information on the modal properties of the studied object, which allowed to confirm the effectiveness of the selected method of analysis.

5

Stator winding fault detection of permanent magnet synchronous motors based on the bispectrum analysis

Pietrzak Przemysław, Wolkiewicz Marcin

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2022

|

Vol. 70, nr 2

art. no. e140556

EN

The popularity of high-efficiency permanent magnet synchronous motors in drive systems has continued to grow in recent years. Therefore, also the detection of their faults is becoming a very important issue. The most common fault of this type of motor is the stator winding fault. Due to the destructive character of this failure, it is necessary to use fault diagnostic methods that facilitate damage detection in its early stages. This paper presents the effectiveness of spectral and bispectrum analysis application for the detection of stator winding faults in permanent magnet synchronous motors. The analyzed diagnostic signals are stator phase current, stator phase current envelope, and stator phase current space vector module. The proposed solution is experimentally verified during various motor operating conditions. The object of the experimental verification was a 2.5 kW permanent magnet synchronous motor, the construction of which was specially prepared to facilitate inter-turn short circuits modelling. The application of bispectrum analysis discussed so far in the literature has been limited to vibration signals and detecting mechanical damages. There are no papers in the field of motor diagnostic dealing with the bispectrum analysis for stator winding fault detection, especially based on stator phase current signal.

6

Application of Spectral and Wavelet Analysis of Stator Current to Detect Angular Misalignment in PMSM Drive Systems

Pietrzak Przemysław, Wolkiewicz Marcin

Power Electronics and Drives

|

2021

|

Vol. 6 (41)

42--60

EN

This paper deals with the selected methods of detecting angular misalignment in drive systems with a permanent magnet synchronous motor (PMSM), which are based on the analysis of the stator phase current signal, as well as their experimental verification and comparison. The proposed and compared methods are spectral analysis and wavelet analysis of the stator current, stator current envelope, stator current space vector module. Furthermore, the influence of power supply frequency and load torque on the performance of the proposed diagnostic methods is also discussed. The experimental tests were carried out for an undamaged motor and for two levels of angular misalignment. The article discusses the question of exactly what damage symptoms can be extracted from each of the methods. In the case of spectral analyses, it is demonstrated which multiplicities of the failure frequency are the most sensitive to misalignment and the least sensitive to changes in motor operating condition, which may be considered novel in the case of drive systems with permanent magnet motors. It is also proven that discrete wavelet transform (DWT) of the envelope and monitoring of the value of the relevant components allows the detection of misalignment with the availability of measuring current only in one phase in various motor operating conditions.

7

Analysis of changes in the angular velocity of the crankshaft of the marine engine for diagnosing the wear and location the failure of the fuel injection system

Drewing Sebastian, Abramczyk Norbert, Żuk Daria

Mechanics and Mechanical Engineering

|

2021

|

Vol. 25, nr 1

72--76

EN

The combustion process can be simply described as periodic explosions in a cylinder with its frequency dependent on the number of cylinders and the rotational speed of the shaft. In practice, uniformity of combustion parameters in every cylinder is almost impossible. Due to this fact, instantaneous angular acceleration does not remain the same at the ends of the crankshaft. These observations formed the basis for the investigation of the instantaneous angular speed of the crankshaft ends. To investigate the influence of the failure behavior of the fuel systems during a shaft’s rotational movement, a series of experiments were planned. For the simulations, a medium-speed marine engine driving electro generator was selected. The failure simulation was based on the installation of clogged spray holes, draining of part of fuel dose from high-pressure pump and decreasing of injection pressure by a lower tension of the injector spring. The results of measurement were processed and analyzed through a comparison of the fast Fourier transform spectra. As a general conclusion, a difference between general harmonics order of magnitudes was detected.

8

High Performance DIF-FFT Using Dissimilar Partitioned LUT Based Distributed Arithmetic

Cheepurupalli Kusma Kumari, Charan Muntha, Rao Jammu Bhaskara, Noor Mahammad S.

International Journal of Electronics and Telecommunications

|

2021

|

Vol. 67, No. 4

631--637

EN

Real-time data processing systems utilize Digital Signal Processing (DSP) functions as the base modules. Most of the DSP functions involve the implementation of Fast Fourier Transform (FFT) to convert the signals from one domain to another domain. The major bottleneck of Decimation in frequency - Fast Fourier Transform (DIF-FFT) implementation lies in using a number of Multipliers. Distributed arithmetic (DA) is considered as one of the efficient techniques to implement DIF-FFT. In this approach, the multipliers are not used. The proposed technique exploits the very advantage of the look-up table by storing the Twiddle factors, thereby avoiding the multipliers required in the butterfly structure. DIF-FFT using Distributed Arithmetic (DIF-FFT DA) models, with different adders such as Ripple carry adder (RCA), Carry-lookahead adder (CLA), and Sklansky prefix graph adder, are proposed in this paper. The three proposed models are synthesized using Cadence 6.1 EDA tools with a 45nm CMOS technology. Compared to the traditional method, it is observed that the area is improved by 53.11%, 53.35%, and 50.15%, power is improved by 42.31%, 42.52%, and 40.39%, and delay is improved by 45.26%, 45.42%, 41.80%, respectively.

9

Chaotic assessment of the heave and pitch dynamics motions of air cushion vehicles

Sowayan A. S.

International Journal of Applied Mechanics and Engineering

|

2021

|

Vol. 26, no. 2

219--234

EN

In this study, a three degrees of freedom nonlinear air cushion vehicle (ACV) model is introduced to examine the dynamic behavior of the heave and pitch responses in addition to the cushion pressure of the ACV in both time and frequency domains. The model is based on the compressible flow Bernoulli’s equation and the thermodynamics nonlinear isentropic relations along with the Newton second law of translation and rotation. In this study, the dynamical investigation was based on a numerical simulation using the stiff ODE solvers of the Matlab software. The chaotic investigations of the proposed model are provided using the Fast Fourier Transform (FFT), the Poincaré maps, and the regression analysis. Three control design parameters are investigated for the chaotic studies. These parameters are: ACV mass (M), the mass flow rate entering the cushion volume (in), and the ACV base radius (r). Chaos behavior was observed for heave, and pitch responses as well as the cushion pressure.

10

Deblurring approach for motion camera combining FFT with α-confidence goal optimization

Huang Lve, Wu Lushen, Xiao Wenyan, Peng Qingjin

Optica Applicata

|

2020

|

Vol. 50, nr 2

185--198

EN

Sharp images ensure success in the object detection and recognition from state-of-art deep learning methods. When there is a fast relative motion between the camera and the object being imaged during exposure, it will necessarily result in blurred images. To deblur the images acquired under the camera motion for high-quality images, a deblurring approach with relatively simple calculation is proposed. An accurate estimation method of point spread function is firstly developed by performing the Fourier transform twice. Artifacts caused by image direct deconvolution are then reduced by predicting the image boundary region, and the deconvolution model is optimized by an α-confidence statistics algorithm based on the greyscale consistency of the image adjacent columns. The proposed deblurring approach is finally carried out on both the synthetic-blurred images and the real-scene images. The experiment results demonstrate that the proposed image deblurring approach outperforms the existing methods for the images that are seriously blurred in direction motion.

11

The analysis of vibrations in the vehicle with naturally aspirated and turbocharged gasoline engine

Łoza Łukasz

Combustion Engines

|

2020

|

R. 59, nr 2

19--23

EN

In this paper, the author presents a study of vibrations in a passenger vehicle and the possible influence on driver’s body in the process of natural operation. The author describes the dependence of engine size and additional equipment as the possible primary source of the vibration variations and their further propagation in the entire vehicle structure. The analysis was performed on the passenger cars with naturally aspirated and turbocharged gasoline engines. The aim of this study was to verify the level of vibrations in the vehicle structure with these particular engines, especially influence of downsized power unit, during various state of engine operation. The second goal was to examine the vibrations in the specified location related to driver’s body. The measuring method used piezoelectric accelerometers, which were attached to the designated locations in the vehicle and were able to detect variations of the acceleration. The signals were collected as characteristics in the time domain. In order to achieve frequency domain for spectral analyses, the author applied the Fast Fourier Transform (FFT).

12

System for examination of human movement system dysfunctions

Kielan Paweł, Cieciura Marcin

Przegląd Elektrotechniczny

|

2019

|

R. 95, nr 12

140--143

EN

The paper presents the concept of an electronic system of multiple sensors measuring chosen parameters of human’s motion. Set of such sensors continuously measure the position, speed, acceleration, vibrations and trembles of human’s body parts and sends this data to the central computer, where it stored and processed. The structure and principle of operation of the limb motion sensor, which consists of an accelerometer, gyroscope, magnetometer and microcontroller, was described. The article also presents the construction of a measuring station for testing the developed limb motion single sensor. The measured signal was analyzed using a Fast Fourier Transform (FFT) method analyzing harmonics of periodic vibrations. The results of the research have proved that it is possible to detect vibrations of frequency and amplitude that are typical for patients with motion dysfunctions, e.g. with Parkinson's disease.

PL

W artykule przedstawiono koncepcję elektronicznego układu wielu czujników mierzących wybrane parametry ruchu człowieka. Zestaw takich czujników nieprzerwanie mierzy pozycję, prędkość, przyspieszenie, wibracje i drżenia części ciała człowieka i przesyła te dane do komputera centralnego, gdzie są przechowywane i przetwarzane. Opisano budowę i zasadę działania kończynowego czujnika ruchu, który składa się akcelerometru, żyroskopu, magnetometru oraz mikrokontrolera. Jego niewielkie rozmiary i zasilanie bateryjne umożliwia przymocowanie go praktycznie w każdym punkcie ludzkiego ciała. W artykule przedstawiono również budowę stanowiska pomiarowego przeznaczonego do testowania opracowanego pojedynczego czujnika ruchu kończyny. Zmierzony sygnał analizowano za pomocą metody szybkiej transformaty Fouriera (FFT) analizującej harmoniczne drgań. Uzyskane wyniki badań wykazały, że możliwe jest wykrycie drgań częstotliwości i amplitudy typowych dla pacjentów z zaburzeniami ruchowymi, np. z chorobą Parkinsona.

13

Performance and stability analysis of series-cascaded, high-gain, interleaved boost converter for photovoltaic applications

Prasanna Kumar C., Venugopal N.

Power Electronics and Drives

|

2018

|

Vol. 3 (38), No. 1

85--97

EN

Interleaved boost converters (IBCs) are cascaded in parallel in most of the applications. This novel approach connects IBC in series cascade. The IBC has an optimal operating duty cycle of 0.5. Normally, photovoltaic source voltage is low because of space constraints. In order to boost the source voltage, a conventional boost converter is replaced with series-cascaded IBC in this paper. The single-stage IBC also boosts the voltage to twice the input voltage. In the proposed converter, output voltage is about four times the input voltage with the same 0.5 duty cycle. A mathematical model is developed and simulated for the proposed work in MATLAB/Simulink platform. The output of the proposed circuit is analysed through fast Fourier transform to know the harmonic content due to the switching. The system is tested for stability with signal-flow graph modelling. The proposed work is realised using hardware and tested to validate the model.

14

Balance disturbances coefficient as a new value to assess ability to maintain balance on the basis of FFT curves

Jurkojc J.

Acta of Bioengineering and Biomechanics

|

2018

|

Vol. 20, no. 1

143--151

EN

The aim of this study was to formulate a new balance disturbances coefficient enabling objective balance assessment on the basis of fast Fourier transform curves. The article presents the method of coefficient calculation and possible ways of its interpretation. Methods: 11 healthy participants took part in the experiment. There were four measurements: two in real environment with eyes open and eyes closed as well as two in virtual environment with scenery (surroundings) oscillating with frequency 0.7 Hz and 1.4 Hz. Scenery was displayed by means of the Oculus Rift system, whereas position of centre of pressure was measured with the use of Zebris FDM-S platform. Obtained centre of pressure positions were used to calculate fast Fourier transform, and then balance disturbances coefficient. Results: Comparisons of coefficient values obtained for the whole group and two selected participants were presented in order to explain how to interpret and use the coefficient. For better explanation of coefficient interpretation the most popular time domain stabilometric quantities and fast Fourier transform curves were presented as well. Conclusions: The balance disturbances coefficient makes it possible to quantitatively and objectively determine, on the basis of fast Fourier transform curves, the influence of the oscillating scenery on the tested person as well as show how the overall equilibrium of that person was disturbed.

15

Measurement of Surface Profile and Surface Roughness of Fibre-Optic Interconnect by Fast Fourier Transform

Lin C. S., Yang S. W., Lin H. L., Li J. W.

Metrology and Measurement Systems

|

2017

|

Vol. 24, nr 2

381--390

EN

This study proposes a surface profile and roughness measurement system for a fibre-optic interconnect based on optical interferometry. On the principle of Fizeau interferometer, an interference fringe is formed on the fibre end-face of the fibre-optic interconnect, and the fringe pattern is analysed using the Fast Fourier transform method to reconstruct the surface profile. However, as the obtained surface profile contains some amount of tilt, a rule for estimating this tilt value is developed in this paper. The actual fibre end-face surface profile is obtained by subtracting the estimated tilt amount from the surface profile, as calculated by the Fast Fourier transform method, and the corresponding surface roughness can be determined. The proposed system is characterized by non-contact measurement, and the sample is not coated with a reflector during measurement. According to the experimental results, the difference between the roughness measurement result of an Atomic Force Microscope (AFM) and the measurement result of this system is less than 3 nm.

16

Effect of ADC Resolution on Low-Frequency Electrical Time-Domain Impedance Spectroscopy

Namin R. L., Ashtiani S. J.

Metrology and Measurement Systems

|

2017

|

Vol. 24, nr 2

425--436

EN

In this paper, the effect of the resolution of an analogue-to-digital converter (ADC) on the accuracy of timedomain low-frequency electrical impedance spectroscopy is examined. For the first time, we demonstrated that different wideband stimuli signals used for impedance spectroscopy have different sensitivities to the resolution of ADC used in impedance spectroscopy systems. We also proposed Ramp and Half-Gaussian signals as new wideband stimulating signals for EIS. The effect of ADC resolution was studied for Sinc, Gaussian, Half-Gaussian, and Ramp excitation signals using both simulation and experiments. We found that Ramp and Half-Gaussian signals have the best performance, especially at low frequencies. Based on the results, a wideband electrical impedance spectroscopy circuit was implemented with a high accuracy at frequencies bellow 10 Hz.

17

Study on the Friction Sound Properties of Natural-Fiber Woven Fabrics

Wang P.-N., Ho M.-H., Cheng K.-B., Murray R., Lin C.-H.

Fibres & Textiles in Eastern Europe

|

2017

|

Vol. 25, no. 2 (122)

34--42

EN

An innovative frictional sound automatic measuring system (FSAMS) was designed and used in this study to investigate the frictional sound generated when natural-fibre woven fabrics are rubbed together. Frictional sound measurements made using the automatic FSAMS were compared with those from a manual frictional sound measuring system (Manual FSAMS). The frictional sounds of four natural-fiber woven fabrics (i.e., cotton, linen, silk, and wool) were recorded; the Fast Fourier Transform method was used to convert time domain signals into frequency domain signals, and the maximum sound amplitude (MSA) and level pressure of the total sound (LPTS) of cotton, linen, silk, and wool were calculated. The results of a t test, analysis of variance, data reproducibility, and cluster spectrums measured from the four natural-fiber woven fabrics were compared for the two test equipment systems. The results from the t test and analysis of variance showed significant differences in the MSA and LPTS measured. Data reproducibility was superior to the automatic FSAMS compared with the manual FSAMS, and the cluster spectrums were more readily distinguishable.

PL

W celu zbadania szumu generowanego podczas tarcia o siebie tkanin z włókien naturalnych zaprojektowano i wykorzystano innowacyjny, automatyczny system pomiaru dźwięku ciernego (FSAMS). Porównano wyniki otrzymane za pomocą FSAMS z wynikami otrzymanymi przy użyciu systemu manualnego (Manual FSAMS). Do badania użyto czterech tkanin z włókien naturalnych: bawełny, lnu, jedwabiu i wełny. Przeprowadzono analizę statystyczną otrzymanych wyników. Analiza danych wykazała, że wartości szumu zmierzone przy użyciu FSAMS były bardziej stabilne i reprezentatywne, niż te otrzymane przy użyciu Manual FSAMS, ponieważ w przypadku systemu manualnego na wyniki pomiaru ma wpływ czynnik ludzki i hałasy otoczenia, które powodują duże błędy eksperymentalne.

18

Comparative Study on the Frictional Sound Properties of Woven Fabrics

Wang P.-N., Ho M.-H., Cheng K.-B., Murray R., Lin C.-H.

Fibres & Textiles in Eastern Europe

|

2017

|

Vol. 25, no. 4 (124)

36--44

EN

An innovative Frictional Sound Automatic Measuring System (FSAMS) was designed to collect and enable analysis of the frictional sound spectra of four natural fibre woven fabrics which included cotton, linen, silk, and wool. The Fast Fourier Transform (FFT) method was used to convert time-domain signals into frequency-domain signals to enable the maximum sound amplitude (MSA) and the level pressure of the total sound (LPTS) of the cotton, linen, silk, and wool fabrics to be calculated and analysed. Subsequently auto-regression formulae were used to calculate the fabric auto-regressive coefficients (ARC, ARF, and ARE); the correlations between fabric frictional sound in terms of LPTS and AR coefficients, and mechanical properties as measured by KES-FB were also evaluated. Stepwise regression was then used to identify the key frictional sound parameters for the four types of fabric. The results show that LPTS values for cotton, linen, silk, and wool fabrics increase with their ARC values. It was revealed that the key mechanical parameters affecting fabric frictional sound for the four natural fibre woven fabrics were not the same for each fabric type: the parameters that influenced LPTS values were the fabric weight and bending hysteresis for the cotton fabric, tensile energy for the linen, tensile resilience for the silk and shear hysteresis at a 5° shear angle for the wool fabric.

PL

Do analizy spektrum akustycznego czterech tkanin (bawełnianej, lnianej, jedwabnej i wełnianej) zastosowano innowacyjny system automatycznego pomiaru dźwięku tarcia (FSAMS). Do przekształcania sygnałów w dziedzinie czasu w sygnały w dziedzinie częstotliwości wykorzystano metodę szybkiej transformaty Fouriera (FFT). Następnie obliczono współczynniki autoregresji tkanin (ARC, ARF i ARE) i oceniono właściwości mechaniczne tkanin. Wyniki pokazują, że wartości poziomu ciśnienia dźwięku totalnego (LPTS) dla tkanin bawełnianych, lnianych, jedwabnych i wełnianych wzrastają wraz z wartościami współczynnika ARC. Wykazano również, że kluczowe parametry mechaniczne wpływające na tarcie tkaniny nie były takie same dla wszystkich typów tkanin. Parametrami mechanicznymi wpływającymi na wartości LPTS tkaniny bawełnianej były: ciężar i histereza zginania tkaniny, w przypadku tkaniny lnianej największy wpływ miała siła rozciągania, a w przypadku tkaniny wełnianej sprężystość powrotna.

19

Effectiveness of Fast Fourier Transform implementations on GPU and CPU

Puchała D., Stokfiszewski K., Szczepaniak B., Yatsymirskyy M.

Przegląd Elektrotechniczny

|

2016

|

R. 92, nr 7

69--71

EN

In this paper, we present the results of comparison of the effectiveness of selected variants of radix-2 Fast Fourier Transform (FFT) algorithms implemented on both Graphics (GPU) and Central (CPU) Processing Units. The considered algorithms differ in memory consumption and the arrangement of data-flow paths which affects the global memory coalescing and cache memory exploitation. The obtained results allow to indicate the variants of FFT algorithms which are best suited for GPU and CPU architectures, to confirm the advisability of GPU oriented calculations of FFT and to formulate a guideline for implementations of fast algorithms of various linear transforms.

XX

W niniejszej pracy przedstawiono wyniki porównania efektywności wybranych wariantów algorytmów szybkiej transformaty Fouriera (FFT) typu radix-2 realizowanych zarówno dla procesorów graficznych (GPU) jak i typowych jednostek centralnych (CPU). Rozważane algorytmy różnią się zapotrzebowaniem pamięciowym oraz postaciami grafów przepływu danych, które mają wpływ na spójność wykorzystania pamięci globalnej oraz pamięci cache jednostek GPU i CPU. Uzyskane wyniki pozwalają na wskazanie wariantów algorytmów FFT, które są najlepiej dostosowane dla architektur GPU i CPU, pozwalają też potwierdzić celowość realizacji implementacji FFT zorientowanych na wykorzystanie jednostek GPU, a także sformułować ogólne wytyczne dla implementacji zorientowanych na wykorzystanie jednostek GPU algorytmów szybkich przekształceń liniowych.

20

Analiza drgań oraz wyważanie urządzeń wirnikowych metodą amplitudowo-fazową z wykorzystaniem czujników i oscyloskopu cyfrowego

Łuniewski S.

Mechanik

|

2016

|

R. 89, nr 7

747--749

PL

Artykuł omawia zagadnienia analizy drgań oraz wyważania urządzeń wirnikowych metodą amplitudowo-fazową z wykorzystaniem wyłącznie czujników i oscyloskopu cyfrowego. Wyważaniu poddany został prototyp wirnika wyświetlacza wirującego. Celem badania było zniwelowanie niewyważenia wirnika, jak również potwierdzenie zasadności opracowanego sposobu wyważania.

EN

Article deals issues vibration analysis and balancing of rotating devices using amplitude- phase method, with the use only sensors and digital scope. The balancing has been subjected to a prototype rotor of the rotating display. The aim of the study was to overcome the unbalance of the machine, as well as confirmation of the developed balancing method.