DIAGNOSTICS WITH A MULTI-CHANNEL MEASURING SYSTEM WITH A FLEXIBLE STRUCTURE OF BOSCH INJECTORS

At the CR-Jet 4E stand, the vibroacoustic signals of BOSCH injectors were studied using a multichannel system with a flexible structure in the BGATU Educational Institution. They were processed in the Mathcad system with spectral analysis and wavelet transformations in MATLAB programs. (Research purpose) The research purpose is in analyzing the vibration characteristics of BOSCH injectors, identifying possible malfunctions and predict their service life. (Materials and methods) The article presents testing results of a new and working nozzle at an injection pressure of 158, 200 and 1000 bar. In five tests it were used the MPU6050 vibration sensors, the INMP621 microphone, and the temperature sensor. The vibration signals were displayed along the xyz axes according to the amplitude-frequency response with the Fourier transform. (Results and discussion) The article presents graphs of wavelet transformations and amplitude-frequency characteristics from five binary files of accelerometer signals and sound files of injectors. The article presents the accelerometer signals on the y-axis at the top of the graphs, the spectrum of their constancy in the middle, and the scalogram at the bottom. For worn-out injectors, the spectrum of constancy is less expressed, the main signal peaks are in the frequencies of 150 and 300 hertz, they are less than in the new nozzle, and the amplitudes are higher up to 800 units. For the new nozzle, the uniform peaks are less than 200 units. The acoustic amplitude of the worn–out nozzle is 150 units, and the new one at frequencies up to 250 hertz is up to 120 units. (Conclusion) Studies of BOSCH injectors with signal processing in the Mathcad system, followed by spectral analysis and wavelet transformations using the MATLAB software package, have shown that the worn-out injectors are characterized by a less expressed spectrum of oscillation constancy. The research goals have not been achieved, but they deepen the traditional diagnosis.

Wavelet transformation on a finite interval

Integral transformations on a finite interval with a singular basis wavelet are considered. Using a sequence of such transformations, the problem of nonparametric approximation of a function is solved. Traditionally, it is assumed that the validity condition must be met for a basic wavelet (the average value of the wavelet must be zero). The paper develops the previously proposed method of singular wavelets when the tolerance condition is not met. In this case Delta-shaped functions that participate in Parzen – Rosenblatt and Nadaray – Watson estimations can be used as a basic wavelet. The set of wavelet transformations for a function defined on a numeric axis, defined locally, and on a finite interval were previously investigated. However, the study of the convergence of the decomposition on a finite interval was carried out only in one particular case. It was due to technical difficulties when trying to solve this problem directly. In the paper the idea of evaluating the periodic continuation of a function defined initially on a finite interval is implemented. It allowed to formulate sufficient convergence conditions for the expansion of the function in a series. An example of approximation of a function defined on a finite interval using the sum of discrete wavelet transformations is given.

DIAGNOSTICS WITH A MULTI-CHANNEL MEASURING SYSTEM WITH A FLEXIBLE STRUCTURE OF BOSCH INJECTORS

At the CR-Jet 4E stand, the vibroacoustic signals of BOSCH injectors were studied using a multichannel system with a flexible structure in the BGATU Educational Institution. They were processed in the Mathcad system with spectral analysis and wavelet transformations in MATLAB programs. (Research purpose) The research purpose is in analyzing the vibration characteristics of BOSCH injectors, identifying possible malfunctions and predict their service life. (Materials and methods) The article presents testing results of a new and working nozzle at an injection pressure of 158, 200 and 1000 bar. In five tests it were used the MPU6050 vibration sensors, the INMP621 microphone, and the temperature sensor. The vibration signals were displayed along the xyz axes according to the amplitude-frequency response with the Fourier transform. (Results and discussion) The article presents graphs of wavelet transformations and amplitude-frequency characteristics from five binary files of accelerometer signals and sound files of injectors. The article presents the accelerometer signals on the y-axis at the top of the graphs, the spectrum of their constancy in the middle, and the scalogram at the bottom. For worn-out injectors, the spectrum of constancy is less expressed, the main signal peaks are in the frequencies of 150 and 300 hertz, they are less than in the new nozzle, and the amplitudes are higher up to 800 units. For the new nozzle, the uniform peaks are less than 200 units. The acoustic amplitude of the worn-out nozzle is 150 units, and the new one at frequencies up to 250 hertz is up to 120 units. (Conclusion) Studies of BOSCH injectors with signal processing in the Mathcad system, followed by spectral analysis and wavelet transformations using the MATLAB software package, have shown that the worn-out injectors are characterized by a less expressed spectrum of oscillation constancy. The research goals have not been achieved, but they deepen the traditional diagnosis.

Isolation of a periodic component by singular wavelet decomposition

In this paper, we propose to use a discrete wavelet transform with a singular wavelet to isolate the periodic component from the signal. Traditionally, it is assumed that the validity condition must be met for a basic wavelet (the average value of the wavelet is zero). For singular wavelets, the validity condition is not met. As a singular wavelet, you can use the Delta-shaped functions, which are involved in the estimates of Parzen-Rosenblatt, Nadaraya-Watson. Using singular value of a wavelet is determined by the discrete wavelet transform. This transformation was studied earlier for the continuous case. Theoretical estimates of the convergence rate of the sum of wavelet transformations were obtained; various variants were proposed and a theoretical justification was given for the use of the singular wavelet method; sufficient conditions for uniform convergence of the sum of wavelet transformations were formulated. It is shown that the wavelet transform can be used to solve the problem of nonparametric approximation of the function. Singular wavelet decomposition is a new method and there are currently no examples of its application to solving applied problems. This paper analyzes the possibilities of the singular wavelet method. It is assumed that in some cases a slow and fast component can be distinguished from the signal, and this hypothesis is confirmed by the numerical solution of the real problem. A similar analysis is performed using a parametric regression equation, which allows you to select the periodic component of the signal. Comparison of the calculation results confirms that nonparametric approximation based on singular wavelets and the application of parametric regression can lead to similar results.

Moving Objects Detection Based on Frequency Domain

In this research a proposed technique is used to enhance the frame difference technique performance for extracting moving objects in video file. One of the most effective factors in performance dropping is noise existence, which may cause incorrect moving objects identification. Therefore it was necessary to find a way to diminish this noise effect. Traditional Average and Median spatial filters can be used to handle such situations. But here in this work the focus is on utilizing spectral domain through using Fourier and Wavelet transformations in order to decrease this noise effect. Experiments and statistical features (Entropy, Standard deviation) proved that these transformations can stand to overcome such problems in an elegant way.

The Application of Wavelet-transformation for Noise Suppression in Video Information Received from on-Board Camera Systems of Aircrafts

Статья посвящена синтезу алгоритма шумоподавления в видеоинформации, поступающей от бортовых съёмочных систем летательных аппаратов, основанному на технологии дискретных вейвлет-преобразований. Показано, что разработанный метод является развитием фильтрации Колмогорова-Винера, использующей для шумоподавления дискретное преобразование Фурье. The article is devoted to the synthesis of the noise reduction algorithm in the video information received from on-Board camera systems of aircrafts, based on the technology of discrete wavelet transformations. It is shown that the developed method is the extension of Kolmogorov-Wiener filtration using discrete Fourier transform for noise reduction.