Applied sciences

Metrology and Measurement Systems

Content

Metrology and Measurement Systems | 2011 | No 2 |

Abstract

This paper presents an overview of algorithms for one-phase active power estimation using digital signal processing in the time domain and in the frequency domain, and compares the properties of these algorithms for a sinusoidal test signal. The comparison involves not only algorithms that have already been published, but also a new algorithm. Additional information concerning some known algorithms is also included. We present the results of computer simulations in MATLAB and measurement results gained by means of computer plug-in boards, both multiplexed and using simultaneous signal sampling. The use of new cosine windows with a recently published iterative algorithm is also included, and the influence of additive noise in the test signal is evaluated.

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Abstract

An implemented impedance measuring instrument is described in this paper. The device uses a dsPIC (Digital Signal Peripheral Interface Controller) as a processing unit, and a DDS (Direct Digital Synthesizer) to stimulate the measurement circuit composed by the reference impedance and the unknown impedance. The voltages across the impedances are amplified by programmable gain instrumentation amplifiers and then digitized by analog to digital converters. The impedance is measured by applying a seven-parameter sine-fitting algorithm to estimate the sine signal parameters. The dsPIC communicates through RS-232 or USB with a computer, where the measurement results can be analyzed. The device also has an LCD to display the measurement results.

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Abstract

Obtaining discrete data is inseparably connected with losing information on surface properties. In contact measurements, the ball tip functions as a mechanical-geometrical filter. In coordinate measurements the coordinates of the measurement points of a discrete distribution on the measured surface are obtained. Surface geometric deviations are represented by a set of local deviations, i.e. deviations of measurement points from the nominal surface (the CAD model), determined in a direction normal to this surface. The results of measurements depend both on the ball tip diameter and the grid size of measurement points. This article presents findings on the influence of the ball tip diameter and the grid size on coordinate measurement results along with the experimental results of measurement of a free-form milled surface, in order to determine its local geometric deviations. One section of the surface under research was measured using different measurement parameters. The whole surface was also scanned with different parameters, observing the rule of selecting the tip diameter d and the sampling interval T in the ratio of 2:1.

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Abstract

Freeform surfaces have wider engineering applications. Designers use B-splines, Non-Uniform Rational B-splines, etc. to represent the freeform surfaces in CAD, while the manufacturers employ machines with controllers based on approximating functions or splines. Different errors also creep in during machining operations. Therefore the manufactured freeform surfaces have to be verified for conformance to design specification. Different points on the surface are probed using a coordinate measuring machine and substitute geometry of surface established from the measured points is compared with the design surface. The sampling points are distributed according to different strategies. In the present work, two new strategies of distributing the points on the basis of uniform surface area and dominant points are proposed, considering the geometrical nature of the surfaces. Metrological aspects such as probe contact and margins to be provided along the sides have also been included. The results are discussed in terms of deviation between measured points and substitute surface as well as between design and substitute surfaces, and compared with those obtained with the methods reported in the literature.

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Abstract

The objective of the submitted paper is to analyze the influence of the load on the calibration of micro-hardness and hardness testers. The results were validated by Measurement Systems Analysis (MSA), Analysis of Variance (ANOVA) and Z-score. The relationship between the load and micro-hardness in calibration of micro-hardness testers cannot be explained by Kick's Law (Meyer's index "n" is different from 2). The conditions of Kick's Law are satisfied at macro-hardness calibration, the values of "n" are close to 2, regardless of the applied load. The apparent micro-hardness increases with the increase of the load up to 30 g; the reverse indentation size effect (ISE) behavior is typical for this interval of the loads. The influence of the load on the measured micro-hardness is statistically significant for majority of calibrations.

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Abstract

It is now widely recognized that the evaluation of the uncertainty associated with a result is an essential part of any quantitative analysis. One way to use the estimation of measurement uncertainty as a metrological critical evaluation tool is the identification of sources of uncertainty on the analytical result, knowing the weak steps, in order to improve the method, when it is necessary. In this work, this methodology is applied to fuel analyses and the results show that the relevant sources of uncertainty are: beyond the repeatability, the resolution of the volumetric glassware and the blank in the analytical curve that are little studied.

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Abstract

The paper presents definitions and relative measures of the system sensitivity and sensitivity of its errors. The model of a real system and model of an ideal measuring system were introduced. It allows to determine the errors of the system. The paper presents also how to use the error sensitivity analysis carried out on the models of the measuring system to the correction of the nonlinearity error of its static characteristic. The corrective function is determined as a relation between the input variable of the tested system and its chosen parameter. The use of the proposed method has been presented on the example of a phase angle modulator. The obtained results have been compared with the results of analytic calculations. The idea of a phase angle modulator is also presented.

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Abstract

The article presents the prototype of a measurement system with a hot probe, designed for testing thermal parameters of heat insulation materials. The idea is to determine parameters of thermal insulation materials using a hot probe with an auxiliary thermometer and a trained artificial neural network. The network is trained on data extracted from a nonstationary two-dimensional model of heat conduction inside a sample of material with the hot probe and the auxiliary thermometer. The significant heat capacity of the probe handle is taken into account in the model. The finite element method (FEM) is applied to solve the system of partial differential equations describing the model. An artificial neural network (ANN) is used to estimate coefficients of the inverse heat conduction problem for a solid. The network determines values of the effective thermal conductivity and effective thermal diffusivity on the basis of temperature responses of the hot probe and the auxiliary thermometer. All calculations, like FEM, training and testing processes, were conducted in the MATLAB environment. Experimental results are also presented. The proposed measurement system for parameter testing is suitable for temporary measurements in a building site or factory.

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Abstract

In this paper, we propose a new method of measuring the target velocity by estimating the scaling parameter of a chaos-generating system. First, we derive the relation between the target velocity and the scaling parameter of the chaos-generating system. Then a new method for scaling parameter estimation of the chaotic system is proposed by exploiting the chaotic synchronization property. Finally, numerical simulations show the effectiveness of the proposed method in target velocity measurement.

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Abstract

This document analyses qualities of methods used for testing dynamical parameters of Digital-to-Analog Converters (DAC) using a multi-frequency signal. As the source for these signals, Amplitude Modulated (AM) and Frequency Modulated (FM) signals are used. These signals are often used in radio engineering. Results of the tests, like Effective Number of Bits (ENOB), Signal-to-Noise and Distortion (SINAD), are evaluated in the frequency domain and they are compared with standard results of Sine Wave FFT test methods. The aim of this research is firstly to test whether it is possible to test a DAC using modulated signals, secondly to reduce testing time, while estimating band performance of DAC.

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Abstract

Focus of the vibration expert community shifts more and more towards diagnosing machines subjected to varying rotational speeds and loads. Such machines require order analysis for proper fault detection and identification. In many cases phase markers (tachometers, encoders, etc) are used to help performing the resampling of the vibration signals to remove the speed fluctuations and smearing from the spectrum (order tracking). However, not all machines have the facility to install speed tracking sensors, due to design or cost reasons, and the signal itself has to then be used to extract this information. This paper is focused on the problem of speed tracking in wind turbines, which represent typical situations for speed and load variation. The basic design of a wind turbine is presented. Two main types of speed control i.e. stall and pitch control are presented,. The authors have investigated two methods of speed tracking, using information from the signal (without relying on a speed signal). One method is based on extracting a reference signal to use as a tachometer, while the other is phase-based (phase demodulation). Both methods are presented and applied to the vibration data from real wind turbines. The results are compared with each other and with the actual speed data.

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Abstract

Cardiovascular system diseases are the major causes of mortality in the world. The most important and widely used tool for assessing the heart state is echocardiography (also abbreviated as ECHO). ECHO images are used e.g. for location of any damage of heart tissues, in calculation of cardiac tissue displacement at any arbitrary point and to derive useful heart parameters like size and shape, cardiac output, ejection fraction, pumping capacity. In this paper, a robust algorithm for heart shape estimation (segmentation) in ECHO images is proposed. It is based on the recently introduced variant of the level set method called level set without edges. This variant takes advantage of the intensity value of area information instead of module of gradient which is typically used. Such approach guarantees stability and correctness of algorithm working on the border between object and background with small absolute value of image gradient. To reassure meaningful results, the image segmentation is proceeded with automatic Region of Interest (ROI) calculation. The main idea of ROI calculations is to receive a triangle-like part of the acquired ECHO image, using linear Hough transform, thresholding and simple mathematics. Additionally, in order to improve the images quality, an anisotropic diffusion filter, before ROI calculation, was used. The proposed method has been tested on real echocardiographic image sequences. Derived results confirm the effectiveness of the presented method.

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Abstract

A high accurate electronic instrument transformer calibration system is introduced in this paper. The system uses the fourth-order convolution window algorithm for the error calculation method. Compared with Fast Fourier Transform, which is recommended by standard IEC-60044-8 (Electronic current transformers), it has higher accuracy. The relative measuring errors caused by asynchronous sampling could be reduced effectively without any special hardware technique adopted. The results show that the ratio error caused by asynchronous sampling can be reduced to 10-4, and the phase error can be reduced to 10-3 degrees when the deviation of frequency is within ±0.5 Hz. The present method of measurement processing is achieved by a high-accuracy USB multifunction data acquisition (DAQ) card and virtual measurement devices, with low cost, short exploitation period and high stability.

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Abstract

A new method measuring of mass in electronic system of scales has been described. The main element of this system is inductive measuring load cell, which was compared with strain gauge load cell. The aim of the paper is described advantages of the inductive measuring system of mass and explain some main problems of this system. Digital correction of the mechanical errors of the beam like: hysteresis, creep material of the beam under constant load, influence of ambient temperature was described.

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Abstract

This paper presents the results of the theoretical and practical analysis of selected features of the function of conditional average value of the absolute value of delayed signal (CAAV). The results obtained with the CAAV method have been compared with the results obtained by method of cross correlation (CCF), which is often used at the measurements of random signal time delay. The paper is divided into five sections. The first is devoted to a short introduction to the subject of the paper. The model of measured stochastic signals is described in Section 2. The fundamentals of time delay estimation using CCF and CAAV are presented in Section 3. The standard deviations of both functions in their extreme points are evaluated and compared. The results of experimental investigations are discussed in Section 4. Computer simulations were used to evaluate the performance of the CAAV and CCF methods. The signal and the noise were Gaussian random variables, produced by a pseudorandom noise generator. The experimental standard deviations of both functions for the chosen signal to noise ratio (SNR) were obtained and compared. All simulation results were averaged for 1000 independent runs. It should be noted that the experimental results were close to the theoretical values. The conclusions and final remarks were included in Section 5. The authors conclude that the CAAV method described in this paper has less standard deviation in the extreme point than CCF and can be applied to time delay measurement of random signals.

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Editorial office

Editor-in-Chief
  • Janusz SMULKO, Gdańsk University of Technology, Poland
International Programme Committee
  • Andrzej ZAJĄC, Chairman, Military University of Technology, Poland
  • Bruno ANDO, University of Catania, Italy
  • Martin BURGHOFF, Physikalisch-Technische Bundesanstalt, Germany
  • Marcantonio CATELANI, University of Florence, Italy
  • Numan DURAKBASA, Vienna University of Technology, Austria
  • Domenico GRIMALDI, University of Calabria, Italy
  • Laszlo KISH, Texas A&M University, USA
  • Eduard LLOBET, Universitat Rovira i Virgili, Tarragona, Spain
  • Alex MASON, Liverpool John Moores University, The United Kingdom
  • Subhas MUKHOPADHYAY, Massey University, Palmerston North, New Zealand
  • Janusz MROCZKA, Wrocław University of Technology, Poland
  • Antoni ROGALSKI, Military University of Technology, Poland
  • Wiesław WOLIŃSKI, Warsaw University of Technology, Poland
Associate Editors
  • Zbigniew BIELECKI, Military University of Technology, Poland
  • Vladimir DIMCHEV, Ss. Cyril and Methodius University, Macedonia
  • Krzysztof DUDA, AGH University of Science and Technology, Poland
  • Janusz GAJDA, AGH University of Science and Technology, Poland
  • Teodor GOTSZALK, Wrocław University of Technology, Poland
  • Ireneusz JABŁOŃSKI, Wrocław University of Technology, Poland
  • Piotr JASIŃSKI, Gdańsk University of Technology, Poland
  • Piotr KISAŁA, Lublin University of Technology, Poland
  • Manoj KUMAR, University of Hyderabad, Telangana, India
  • Grzegorz LENTKA, Gdańsk University of Technology, Poland
  • Czesław ŁUKIANOWICZ, Koszalin University of Technology, Poland
  • Rosario MORELLO, University Mediterranean of Reggio Calabria, Italy
  • Fernando PUENTE LEÓN, University Karlsruhe, Germany
  • Petr SEDLAK, Brno University of Technology, Czech Republic
  • Hamid M. SEDIGHI, Shahid Chamran University of Ahvaz, Ahvaz, Iran
  • Roman SZEWCZYK, Warsaw University of Technology, Poland
Language Editors
  • Andrzej Stankiewicz, Gdańsk University of Technology, Poland
Technical Editors
  • Agnieszka Kondratowicz, Gdańsk University of Technology, Poland

Contact

Editorial Office of Metrology and Measurement Systems

Contact:
E-mail: metrology@pg.edu.pl
URL: www.metrology.pg.gda.pl
Phone: (+48) 58 347-1357

Post address:
Editorial Office of Metrology and Measurement Systems
Gdańsk University of Technology, Faculty of Electronics, Telecommunications and Informatics

Instructions for authors

Types of contributions

The following types of papers are published in Metrology and Measurement Systems:
•    invited review papers presenting the current stage of the knowledge (max. 20 edited pages, 3000 characters each),
•    research papers reporting original scientific or technological advancements (10‒12 pages),
•    papers based on extended and updated contributions presented at scientific conferences (max. 12 pages),
•    short notes, i.e. book reviews, conference reports, short news (max. 2 pages).

Manuscript preparation

The text of a manuscript should be written in clear and concise English. The form similar to “camera-ready” with an attached separate file – containing illustrations, tables and photographs – is preferred. For the details of the preferred format of the manuscripts, Authors should consult a recent issue of the journal or the sample article and the guidelines for manuscript preparation. The text of a manuscript should be printed on A4 pages (with margins of 2.5 cm) using a font whose size is 12 pt for main text and 10 pt for the abstract; an even number of pages is strongly recommended. The main text of a paper can be divided into sections (numbered 1, 2, ...), subsections (numbered 1.1., 1.2., ...) and – if needed – paragraphs (numbered 1.1.1., 1.1.2., ...). The title page should include: manuscript title, Authors’ names and affiliations with e-mail addresses. The corresponding Author should be identified by the symbol of an envelope and phone number. A concise abstract of approximately 100 words and with 3–5 keywords should accompany the main text.
Illustrations, photographs and tables provided in the camera-ready form, suitable for reproduction (which may include reduction) should be additionally submitted one per page, larger than final size. All illustrations should be clearly marked on the back with figure number and author’s name. All figures are to have captions. The list of figures captions and table titles should be supplied on separate page. Illustrations must be produced in black ink on white paper or by computer technique using the laser printer with the resolution not lower than 300 dpi, preferably 600 dpi. The thickness of lines should be in the range 0.2–0.5 mm, in particular cases the range 0.1–1.0 mm will be accepted. Original photographs must be supplied as they are to be reproduced (e.g. black and white or colour). Photocopies of photographs are not acceptable.
References should be inserted in the text in square brackets, e.g. [4]; their list numbered in citation order should appear at the end of the manuscript. The format of the references should be as follows: for a journal paper – surname(s) and initial(s) of author(s), year in brackets, title of the paper, journal name (in italics), volume, issue and page numbers. The exemplary format of the references is available at the sample article.

Manuscript submission and processing

Submission procedure. Manuscript should be submitted via Internet Editorial System (IES) ‒ an online submission and peer review system http://www.editorialsystem.com/mms
In order to submit the manuscript via IES, the authors (first-time users) must create an author account to obtain a user ID and password required to enter the system. From the account you create, you will be able to monitor your submission and make subsequent submissions.
The submission of the manuscript in two files is preferred: “Paper File” containing the complete manuscript (with all figures and tables embedded in the text) and “Figures File” containing illustrations, photographs and tables. Both files should be sent in DOC and PDF format as well as. In the submission letter or on separate page in “Figures File”, the full postal address, e-mail and phone numbers must be given for all co-authors. The corresponding Author should be identified.
Copyright Transfer. The submission of a manuscript means that it has not been published previously in the same form, that it is not under consideration for publication elsewhere, and that – if accepted – it will not be published elsewhere. The Author hereby grants the Polish Academy of Sciences (the Journal Owner) the license for commercial use of the article according to the Open Access License which has to be signed before publication.
Review and amendment procedures. Each submitted manuscript is subject to a peer-review procedure, and the publication decision is based on reviewers’ comments; if necessary, Authors may be invited to revise their manuscripts. On acceptance, manuscripts are subject to editorial amendment to suit the journal style.
An essential criterion for the evaluation of submitted manuscripts is their potential impact on the scientific community, measured by the number of repeated quotations. Such papers are preferred at the evaluation and publication stages.
Proofs. Proofs will be sent to the corresponding Author by e-mail and should be returned within 48 hours of receipt.

Other information

Author Benefits. The publication in the journal is free of charge. A sample copy of the journal will be sent to the corresponding Author free of charge.
Colour. For colour pages the Authors will be charged at the rate of 160 PLN or 80 EUR per page. The payment to the bank account of main distributor must be acquitted before the date pointed to Authors by Editorial Office.

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