Discrete wavelet transformation in spectral analysis of vibration processes at hydropower units

Kukharchuk, Vasyl

doi:10.15199/48.2017.03.16

Cited by 12 publications

(14 citation statements)

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“…Machines and mechanisms, particularly those, equipped with the systems of automatic control, at certain parameters can operate in non-stable operation modes. That is why, stability provision is one of the main problems to be solved in the process of the development of the devices with the systems of automatic control [11,27,28]. Especially, it concerns non-stationary operation modes when saving of equilibrium state or the preset motion law by the mechanical system is very important.…”

Section: Analysis Of the Methods Of Variants Moving Systems Stabilitymentioning

confidence: 99%

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Study of the dynamic stability of the belt conveyor adaptive drive

Polishchuk¹

2019

ELECTROTECHNICAL REVIEW

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Dynamic stability of the adaptive hydraulic drive of the belt conveyor is studied with the help of an improved mathematical model constructed taking into account the physical processes that occur during the mechanical system of the conveyor under load changes. The parameters of the adaptive drive, which provide stable operation of the mechanical system in conditions of its overload, are determined.Streszczenie. Dynamiczna stabilność adaptacyjnego napędu hydraulicznego przenośnika taśmowego jest badana za pomocą ulepszonego modelu matematycznego skonstruowanego z uwzględnieniem fizycznych procesów zachodzących podczas mechanicznego systemu przenośnika pod zmianą obciążenia. Określono parametry napędu adaptacyjnego, zapewniające stabilną pracę układu mechanicznego w warunkach jego przeciążenia.. (Badanie stabilności dynamicznej napędu adaptacyjnego przenośnika taśmowego).

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Section: Analysis Of the Methods Of Variants Moving Systems Stabilitymentioning

confidence: 99%

“…Experimental studies of the hydraulic stability of the developed testing stands [22,23,27,29] allow to avoid tedious calculations and composing of mathematical models. However, such methods are rather costly and require certified equipment.…”

Section: Analysis Of the Methods Of Variants Moving Systems Stabilitymentioning

confidence: 99%

Study of the dynamic stability of the belt conveyor adaptive drive

Polishchuk¹

2019

ELECTROTECHNICAL REVIEW

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“…However, there are well-known methods of qualitative and quantitative estimation of transients that allow us to study transitional regimes without solving differential equations. For example, for studying the stability of dynamic systems, A. Hurwitz developed criteria on which it is possible to draw conclusions about their stability or instability, based on the coefficients for the terms of equations [10][11][12].…”

Section: Analytical Substantiation Of the Existence Of Non-stop Periomentioning

confidence: 99%

“…Since, the coefficients a 0 , a 1 , a 2 , a 3 positive, then this transition process has oscillatory character [9,10]. Let's write the A. Hurwitz matrix of stability [11]: (10) .…”

Section: Analytical Substantiation Of the Existence Of Non-stop Periomentioning

confidence: 99%

“…When substituting the value (11) in the differential equation (6) in its characteristic equation, the free term will be negative. Consequently, the transition process in this case will not have oscillatory character, as it is not executed Routh-Hurwitz criterion [11,14,15]. Valve pulser shut-off element will be in stable equilibrium state.…”

Section: Determinants Of the Main Matrix Minors (10)mentioning

confidence: 99%

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Terms of the stability for the control valve of the hydraulic impulse drive of vibrating and vibro-impact machines

Iskovych-Lototsky

Kots

Ivanchuk

et al. 2019

ELECTROTECHNICAL REVIEW

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The working process and regularities of the functioning of vibrating and vibro-impact machines based on hydroimpulse drive with a singlestage valve pulser are analyzed. The essential characteristics determining the conditions for the excitation and existence of periodic oscillations of the valve-pulser shut-off valve are determined. Using the criterion of A. Hurwitz, based on the differential equation of motion, the existence of undamped periodic oscillations of the valve-pulser shut-off valve is analytically justified.Streszczenie. Przeanalizowano działanie i regularność pracy maszyn wibracyjnych oraz maszyn poddawanych wibracjom opartych na napędzie hydro-impulsowym z jednostopniowym zaworem impulsowym. Określono podstawowe cechy wpływające na warunki wzbudzenia oraz występowania drgań okresowych zaworu impulsowego. Przy zastosowaniu kryterium A. Hurwitza, opartego na równaniu różniczkowym ruchu, istnienie nietłumionych drgań okresowych zaworu impulsowego jest analitycznie uzasadnione. (Warunki stabilności zaworu sterującego hydraulicznym napędem impulsowym maszyn wibracyjnych oraz maszyn poddawanych wibracjom).

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Image Retrieval Model Analysis of Digital Library Based on Texture Characteristics

Zhao

2021

Advances in Mathematical Physics

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A new document image retrieval algorithm is proposed in view of the inefficient retrieval of information resources in a digital library. First of all, in order to accurately characterize the texture and enhance the ability of image differentiation, this paper proposes the statistical feature method of the double-tree complex wavelet. Secondly, according to the statistical characteristic method, combined with the visual characteristics of the human eye, the edge information in the document image is extracted. On this basis, we construct the meaningful texture features and use texture features to define the characteristic descriptors of document images. Taking the descriptor as the clue, the content characteristics of the document image are combined organically, and appropriate similarity measurement criteria are used for efficient retrieval. Experimental results show that the algorithm not only has high retrieval efficiency but also reduces the complexity of the traditional document image retrieval algorithm.

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Discrete wavelet transformation in spectral analysis of vibration processes at hydropower units

Cited by 12 publications

References 0 publications

Study of the dynamic stability of the belt conveyor adaptive drive

Study of the dynamic stability of the belt conveyor adaptive drive

Terms of the stability for the control valve of the hydraulic impulse drive of vibrating and vibro-impact machines

Image Retrieval Model Analysis of Digital Library Based on Texture Characteristics

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