scholarly journals ACCOUNTING OF INSTRUMENTAL ERRORS IN THE CONTROL OF WINDINGS OF ELECTRICAL MACHINES WITH THE USE OF QUASI-PERIODIC TEST SIGNALS

2018 ◽  
Vol 61 (3) ◽  
pp. 235-245
Author(s):  
A. A. Sheinikov ◽  
Yu. V. Suchodolov ◽  
V. V. Zelenko
Keyword(s):  
Measuring Instruments ◽  
Mathematical Tool ◽  
Periodic Test ◽  
Useful Signal ◽  
Accuracy Of Measurements ◽  
Correlation Processing ◽  
Time Parameters ◽  
Periodic Signals ◽  
Harmonic Components ◽  
Low Sensitivity

The solution of problems of diagnostics of windings of electric machines is associated with the necessity of selection of quasi-periodic test signals against the background noise. In order to highlight useful signals, as a rule, the differences in spectral compositions of signals and noises are used. Ideally, the shape of the optimal filter frequency response should coincide with the shape of the spectrum of the useful signal, which determines the complexity of such a filter. The aim of the research is to increase the accuracy of measurements and simplify the algorithmic support of measuring systems by developing a mathematical tool that makes it possible to uniquely identify and take into account errors caused by the finiteness of the measurement intervals in the processing. Determining a one-to-one relationship between local variations of signal time parameters and alterations in its spectrum parameters is believed to be the reserve of increase of sensitivity of methods of processing of quasi-periodic signals in the conditions of constant growth of computing capabilities of measuring instruments. Variations in the values of the parameters of the signals lead to a violation of the original distribution of the harmonic components, some of the latter being subjected to the greatest alterations changes, and the some other – to the smallest ones. It is proposed to increase the accuracy of measurements due to the replacement the low-sensitivity registration of alterations in the time parameters of signals with the registration of alterations in the parameters of the characteristic harmonic components of the spectrum, which have a maximum sensitivity to deviations of the controlled parameter and a minimum sensitivity to deviations caused by the instability of the measuring equipment. The mathematical tool corresponding to the practice has been developed, that makes it possible to determine unambiguously the errors caused by finiteness of measurement intervals of quasi-periodic signals. Automatic accounting of these errors makes it possible to do without complex correlation processing of quasi-periodic signals that require large computing resources (time and speed of data processing, the amount of RAM) and to ensure the accuracy of measurements.

Method of estimation of hidden correlation of narrowband noise signals

2019 ◽  
pp. 34-39 ◽  
Author(s):  
E.I. Chernov ◽  
N.E. Sobolev ◽  
A.A. Bondarchuk ◽  
L.E. Aristarhova
Keyword(s):  
Signal Processing ◽  
Digital Signal Processing ◽  
New Technology ◽  
Digital Signal ◽  
Measuring Instruments ◽  
Central Frequency ◽  
Pearson Criterion ◽  
Useful Signal ◽  
Band Limited ◽  
Narrowband Noise

The concept of hidden correlation of noise signals is introduced. The existence of a hidden correlation between narrowband noise signals isolated simultaneously from broadband band-limited noise is theoretically proved. A method for estimating the latent correlation of narrowband noise signals has been developed and experimentally investigated. As a result of the experiment, where a time frag ent of band-limited noise, the basis of which is shot noise, is used as the studied signal, it is established: when applying the Pearson criterion, there is practically no correlation between the signal at the Central frequency and the sum of signals at mirror frequencies; when applying the proposed method for the analysis of the same signals, a strong hidden correlation is found. The proposed method is useful for researchers, engineers and metrologists engaged in digital signal processing, as well as developers of measuring instruments using a new technology for isolating a useful signal from noise – the method of mirror noise images.

Evaluation of the accuracy indicators in determination of the coating thickness by crater grinding method

2020 ◽  
Vol 86 (7) ◽  
pp. 39-44
Author(s):  
K. V. Gogolinsky ◽  
A. E. Ivkin ◽  
V. V. Alekhnovich ◽  
A. Yu. Vasiliev ◽  
A. E. Tyurnina ◽  
...  
Keyword(s):  
Coating Thickness ◽  
Functional Dependence ◽  
Measurement Procedure ◽  
Metrological Certification ◽  
Measuring Instruments ◽  
Properties Of Coatings ◽  
Special Equipment ◽  
Grinding Method ◽  
Accuracy Of Measurements ◽  
Wide Range

Thickness is one of the key indicators characterizing the quality and functional properties of coatings. Various indirect methods (electromagnetic, radiation, optical) most often used in practice to measure thickness are based on the functional dependence of a particular physical parameter of the system «base – coating» on the coating thickness. The sensitivity of these procedures to the certain properties of coatings imposes the main restriction to the accuracy of measurements. Therefore, the development and implementation of the approaches based on direct measurements of geometric parameters of the coating appears expedient. These methods often belong to the class of «destructive» and, in addition to measuring instruments, require the use of special equipment. To ensure the uniformity of measurements in the laboratory or technological control, these methods are isolated as a separate procedure (method) and must undergo metrological certification in accordance with GOST R 8.563–2009. We present implementation, metrological certification and practical application of the method for measuring thickness of coatings by crater-grinding method. The principles of technical implementation of test equipment, measurement procedure and calculation formulas are described. The results of evaluating the accuracy indicators of the proposed procedure by calculation and experimental methods are presented. In both cases, the relative error did not exceed 6%. The applicability of the developed technique is shown for a wide range of coating materials (from soft metals to superhard ceramics) of different thickness (with from units to hundreds of micrometers). Apart from the goals of process control and outgoing inspection, the method can be recommended as a reference measurement procedure for calibration of measures and adjusting samples for various types of thickness gauges.

Half division two-dimensional method for simple sinusoidal quantities parameters accurate measurement

2021 ◽  
pp. 16-21
Author(s):  
Kirill Yu. Solomentsev ◽  
Vyacheslav I. Lachin ◽  
Aleksandr E. Pasenchuk
Keyword(s):  
Measuring Instruments ◽  
Measured Signal ◽  
Two Dimensional ◽  
Measuring Device ◽  
New Approach ◽  
Precision Measuring ◽  
Useful Signal ◽  
Midpoint Method ◽  
Order Of Magnitude ◽  
Current Measuring

Several variants of half division two-dimensional method are proposed, which is the basis of a fundamentally new approach for constructing measuring instruments for sinusoidal or periodic electrical quantities. These measuring instruments are used in the diagnosis of electric power facilities. The most general variant, called midpoint method, is considered. The proposed midpoint method allows you to measure much smaller than using widespread methods, alternating currents or voltages, especially when changing the amplitude of the measured signal in very wide ranges, by 1–2 orders of magnitude. It is shown that using the midpoint method it is possible to suppress sinusoidal or periodic interference in the measuring path, in particular, to measure small alternating current when sinusoidal or periodic interference is 1–2 orders of magnitude higher than the useful signal. Based on the results of comparative tests, it was found that the current measuring device implementing the midpoint method is an order of magnitude more sensitive than the currently used high-precision measuring instruments.

scholarly journals Digital Data Processing Methods for Estimating Tractive Force of Tractors

2021 ◽  
Vol 31 (1) ◽  
pp. 127-142
Author(s):  
Vyacheslav F. Fedorenko ◽  
Vitaly E. Tarkivskiy ◽  
Nikolay P. Mishurov ◽  
Nikolay V. Trubitsyn
Keyword(s):  
Real Time ◽  
Strain Gauge ◽  
Impulse Noise ◽  
Median Filter ◽  
Digital Processing ◽  
Operating Conditions ◽  
Measuring Instruments ◽  
Important Indicator ◽  
Tractive Effort ◽  
Useful Signal

Introduction. When carrying out an energy assessment of agricultural machines and traction tests of tractors, the most important indicator is the value of the tractive effort. The existing methods for determining the tractive effort of tractors imply the use of specialized measuring instruments, such as strain gauges and devices for processing and displaying information. The accuracy of determining the tractive effort is significantly influenced by the physical and mechanical properties of soil. To process the useful signal during the measurement of tractive effort, the data stream of the strain gauge sensor must be subjected to additional digital filtering taking into account the operating conditions of the agricultural unit. Materials and Methods. The functions of changing the tractive effort obtained on the K-744R2 tractor in various gears have been analyzed. An algorithm for digital processing of the signal of a strain gauge force meter based on a median filter has been developed that makes it possible to increase the measurement accuracy. The advantage of the proposed method is the ability to cut off sharp short-term impulse noise and sharp fluctuations in the amplitude of the measured value. Results. A method for determining the amount of tractive effort using median signal processing has been proposed. A device for determining the tractive effort during testing of agricultural tractors and units has been developed. The choice of the main components of the device for determining the magnitude of the tractive effort has been substantiated. As a result of the research, a device for measuring and digital processing of the signal of a force meter based on a microcontroller and specialized software for processing initial data in real time was designed and manufactured. Discussion and Conclusion. The developed method makes it possible to exclude the negative effect of impulse noise arising in the process of measuring the tractive effort of the tractor. The proposed device for measuring the tractive effort of tractors is compatible at the level of the exchange protocol with existing devices, has a high speed of operation in real time, multi-channel operation.

Determination of precision conditions for measuring relative values in mechanical tests of various materials

2021 ◽  
pp. 9-17
Author(s):  
Svetlana Yu. Lohanina ◽  
Olga V. Baranova ◽  
Larisa V. Trubacheva
Keyword(s):  
Wear Resistance ◽  
Mechanical Testing ◽  
Mechanical Tests ◽  
Metrological Characteristics ◽  
Measuring Instruments ◽  
Quantitative Chemical Analysis ◽  
Uniformity Of Measurements ◽  
Multi Stage ◽  
Abrasive Disk ◽  
Accuracy Of Measurements

The problem of insufficient detail of the requirements for the developed and certified measurement methods used in mechanical testing of various materials is considered. The compatibility of the requirements of metrological support for the results of quantitative chemical analysis and indirect results of mechanical tests for the wear resistance of materials when rubbing against a fixed abrasive is relevant. To ensure the accuracy of measurements, it is proposed to use the grain size of the abrasive material and the rotation speed of the abrasive disk as variable factors. In order to establish the requirements for the metrological characteristics of materials during mechanical tests, in particular, when determining the relative wear resistance, the conditions for precision measurements are justified. The results of a multi-stage experiment-testing of materials for wear resistance with the use of various research and consumables, measuring instruments and testing equipment are presented. The conditions for the organization of the experiment in the case of determining other relative mechanical characteristics of the materials under study for establishing precision indicators in the development of methods of mechanical tests for abrasive wear are proposed and justified. The application of the obtained results will allow developers of mechanical testing methods to establish metrological characteristics of materials in compliance with all the requirements of the State System for Ensuring the Uniformity of Measurements of the Russian Federation.

Design Optimization of a Utility Scale Wind Turbine Blade Using a Genetic Algorithm

2016 ◽  
Author(s):  
Khaled Yassin ◽  
Aya Diab ◽  
Zakaria Ghoneim
Keyword(s):  
Genetic Algorithm ◽  
Wind Turbine ◽  
Structural Integrity ◽  
Structural Parameters ◽  
Turbine Rotor ◽  
Mathematical Tool ◽  
Baseline Design ◽  
Cost Of Energy ◽  
The World ◽  
Low Sensitivity

Driven by the increasing fossil fuel prices, global warming and climatic change, the world is currently witnessing an increasing development in renewable energy technologies, particularly those of wind energy. As such, engineers around the world are trying to optimize the design of wind turbines to maximize the captured energy while simultaneously minimizing the cost. This work aims to develop a mathematical tool to be used to compare different wind turbine designs and hence to reach the ultimate goal of an optimized wind turbine rotor designed specifically to operate in the Saharan regions of North Africa and the Middle East. As a case study, the main aerodynamic and structural parameters of the NREL 5MW virtual rotor have been optimized for the wind conditions prevalent at the Zaafarana site in Egypt. Specifically, the airfoil chord lengths and twist angles — smoothed using Bezier curves — as well as the layup sequence of the spar caps have been considered i n the optimization process which was carried out using a Genetic Algorithm (GA) developed i n MATLAB and coupled with NREL’s FAST Modularization Framework. The results showed that the NREL 5MW wind turbine design optimized for the site specific wind conditions of Zaafarana using airfoil families with low-sensitivity to dust accumulation, achieved a drop of 2.41% of the Levelized Cost of Energy of Energy (LCOE) over that of the baseline design. The developed turbine rotor design is tested for structural integrity commensurate with IEC standards.

scholarly journals Intercomparison of MAX-DOAS vertical profile retrieval algorithms: studies on field data from the CINDI-2 campaign

2020 ◽  
Author(s):  
Jan-Lukas Tirpitz ◽  
Udo Frieß ◽  
François Hendrick ◽  
Carlos Alberti ◽  
Marc Allaart ◽  
...  
Keyword(s):  
Lower Troposphere ◽  
Trace Gas ◽  
Optical Absorption Spectroscopy ◽  
Measuring Instruments ◽  
Visible Radiation ◽  
Radiation Spectra ◽  
Tropospheric Aerosol ◽  
Wide Range ◽  
Sun Photometer ◽  
Low Sensitivity

Abstract. Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) is a well-established ground-based measurement technique for the detection of aerosols and trace gases particularly in the boundary layer and the lower troposphere: ultraviolet- and visible radiation spectra of skylight are analysed to obtain information on different atmospheric parameters, integrated over the light path from space to the instrument. An appropriate set of spectra recorded under different viewing geometries ("Multi-Axis") allows retrieval of tropospheric aerosol and trace gas vertical distributions by applying numerical inversion methods. The second Cabauw Intercomparison of Nitrogen Dioxide measuring Instruments (CINDI-2) took place in Cabauw (The Netherlands) in September 2016 with the aim of assessing the consistency of MAX-DOAS measurements of tropospheric species (NO2, HCHO, O3, HONO, CHOCHO and O4). This was achieved through the coordinated operation of 36 spectrometers operated by 24 groups from all over the world, together with a wide range of supporting reference observations (in situ analysers, balloon sondes, lidars, Long-Path DOAS, sun photometer and others). In the presented study, the retrieved CINDI-2 MAX-DOAS trace gas (NO2, HCHO) and aerosol vertical profiles of 15 participating groups using different inversion algorithms are compared and validated against the colocated supporting observations. The profiles were found to be in good qualitative agreement: most participants obtained the same features in the retrieved vertical trace gas and aerosol distributions, however sometimes at different altitudes and of different intensity. Under clear sky conditions, the root-mean-square differences of aerosol optical thicknesses, trace gas (NO2, HCHO) vertical columns and surface concentrations among the results of individual participants vary between 0.01–0.1, (1.5–15) x 1014 molec cm-2 and (0.3–8) x 1010 molec cm-3, respectively. For the comparison against supporting observations, these values increase to 0.02–0.2, (11–55) x 1014 molec cm-2 and (0.8–9) x 1010 molec cm-3. It is likely that a large part of this increase is caused by imperfect spatio-temporal overlap of the different observations. In contrast to what is often assumed, the MAX-DOAS vertically integrated extinction profiles and the sun photometer total aerosol optical thickness were found to not necessarily being comparable quantities, unless information on the real aerosol vertical distribution is available to account for the low sensitivity of MAX-DOAS observations at higher altitudes.

State primary measurement standard of ultrasound power unit in water GET 169-2019

2020 ◽  
pp. 3-8
Author(s):  
Аlexander М. Еnyakov ◽  
Sergey I. Kuznetsov ◽  
Georgiy S. Lukin
Keyword(s):  
Power Unit ◽  
Radiation Effect ◽  
High Tech ◽  
Measuring Instruments ◽  
Measurement Standard ◽  
Primary Measurement ◽  
Accuracy Of Measurements ◽  
Special Measurement ◽  
Primary Measurement Standard ◽  
Ultrasound Power

Results of works on improvement of the state primary special measurement standard of ultrasound power unit in water GET 169-2005 are given. As a result of the inclusion of two new reference ultrasound power meters in the standard, the frequency and dynamic ranges of reproduction and transmission of the power unit to lower-level measuring instruments were expanded using absorbing targets for measuring the radiation effect of the ultrasonic wave and the absorbed ultrasonic energy. That is very important for metrological support of modern high-tech medical ultrasound equipment, including focused high-intensity ultrasound beams for the treatment of cancer. The automation of the measurement process used in the updated standard has reduced significantly the complexity of verification procedures increasing the accuracy of measurements.

scholarly journals Monitoring the Accuracy of Measurements the Load of Industrial Enterprises

2020 ◽  
Vol 63 (5) ◽  
pp. 393-410
Author(s):  
V. A. Anishchenko ◽  
T. V. Pisaruk
Keyword(s):  
A Priori ◽  
Normal Operation ◽  
Measuring Instruments ◽  
Control Methods ◽  
Limit Values ◽  
Industrial Enterprises ◽  
Active Load ◽  
Accuracy Of Measurements ◽  
Reliability Control ◽  
Measured Load

The normalized accuracy of the installed measuring instruments determines the scheduled measurement accuracy of the daily active load of an industrial enterprise. To maintain  it during operation, syntactic and semantic methods can be used to control the reliability of load measurements. During syntactic control, the state of measuring instruments that collect and process information about the enterprise’s load is diagnosed. Semantic control is based on the use of probabilistic characteristics of the measured load. The condition necessary for semantic control is the presence of information redundancy about the values of the monitored load. It is possible to control the load limit values (settings) when a priori information is known about the lower and upper limits in which reliably measured load values in normal operation of the enterprise may be contained. The article considers control methods that use a posteriori redundant information about the dynamics of load alterations in various sections of the daily schedule. These methods include monitoring by the first increments of the load, which characterize the speed of its alterations, as well as control using linear and nonlinear extrapolations of the first increments.  The results of the analysis of probabilistic characteristics of the daily active load of the enterprise and its first increments, which characterize the rate of load change, are presented. The effect of probabilistic characteristics of the first load increments on the boundaries of making a decision about the reliability of measurements is demonstrated. A comparative analysis of the effectiveness of reliability control methods based on the first load increments and their extrapolated values  has been carried out on the example of measurements of daily active load schedules of the “Minsk Motor Plant” JSC.

scholarly journals Determination of the Sensor Placement for Detection Water Quality Problems in Water Supply Systems

2020 ◽  
Vol 20 (1) ◽  
pp. 299-306
Author(s):  
Chan Wook Lee ◽  
Yong Jun Lee ◽  
Ji Seung Park ◽  
Do Guen Yoo
Keyword(s):  
Water Quality ◽  
Flow Direction ◽  
Water Quality Management ◽  
High Sensitivity ◽  
Measuring Instruments ◽  
Water Supply Systems ◽  
Low Sensitivity ◽  
Supply Systems ◽  
The City

The importance of water quality management in pipes has been recently highlighted through the "Red-water phenomenon" in the city of Incheon. This study proposed a methodology for determining the location of measuring instruments during abnormal water quality issues. The proposed method focuses on analyzing the sensitivity of the flow path through a pipe. Additionally, this flow sensitivity through the tube is analyzed by considering both normal and abnormal conditions. The sensitivity of a pipe is the rate at which the water-flow direction changes. Further, a tube with low sensitivity under normal conditions but high sensitivity under abnormal conditions is the pipe for which the instrument should be first installed. The results were analyzed by applying the proposed methodology to a conventional virtual network. It is expected that, in future, the proposed method for determining the location of water quality gauges could be a useful tool for determining the location of instruments during emergencies.

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