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The expression of the accuracy of the gauge and measurement
Svobodová, Helena ; Koška, Petr (referee) ; Pernikář, Jiří (advisor)
The bachelor thesis deals with the issue of measurement, accuracy of measuring instruments and their expressing. It outlines the legislative basis of metrology in the Czech Republic and interprets the definitions of basic terms used in metrology. These definitions are listed in the new edition of International dictionary of metrology (VIM 3:2007). It specifies and exemplifies measurement errors and presents possibilities of their elimination. Further, it describes a simple way of measurement uncertainty determination. The aim of this thesis is to explain the issue in a way that it is understandable and can be applicable for the common metrology practice.
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The theoretical and actual measurement accuracy of TRITOP photogrammetry system
Klus, Patrik ; Mendřický, Radomír (referee) ; Zatočilová, Aneta (advisor)
This diploma thesis examines the impact of selected factors on the measurement accuracy of Tritop photogrammetry system and verifies the validity of theoretical predictive formulas. Primary attention is given to factors that are easily influenced by the inspector - namely number of captured images, shooting distance, number of scale bars and number of coded targets. In addition, experiments dealing with the measurement automation and the use of external color filter are also described in this thesis. Seven scale bars placed on a jig of cube shape were subject of the measurements (according to VDI/VDE 2634 standard). Two approaches were used in order to obtain measurement deviations – reference values, from which the measured data were subtracted to obtain deviations, were known due to the use of scale bars. Second approach consisted in evaluation of deviations from software Tritop Professional. The results showed that the number of photographs and shooting distance have the greatest impact on measurement accuracy of Tritop system. The accuracy was also influenced by number of coded targets in the scene or by use of the external green filter. Measured data were compared to the values obtained from predictive formulas. The results showed that the formula defined by the GOM company has a prediction accuracy of more than 96 %. However the formula is dependent on the input parameter called “Image accuracy” for which the value recommendations are made in this work. The results of this work can help predict measurement uncertainties more precisely and optimize the measurement methodology of Tritop photogrammetry system.
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Problems of measurement and evaluation of switching loop impedance
Švéda, Miroslav ; Bárta, Jan (referee) ; Veselka, František (advisor)
This work is applied to questions about impedance of tripping loop. It deals with problems of measuring impedance of tripping loop, different measurement, procedures and accuracy of these measurements. Further, the work deals with the subsequent evaluation of the measuring impedance of tripping loop and writing of the measurement results. The work also focuses on the impedance of tripping loop in terms of the operation of the protective elements of the electrification system. Finally, the practical measurement of the impedance of tripping loop in real electrical circuits is performed as part of the work.
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Expressing uncertainty of accurate lenght measurement II
Šrámek, Jan ; Pernikář, Jiří (referee) ; Koška, Petr (advisor)
This diploma thesis is supposed to inform readers interested in the distance measurements uncertainty on practical issues connected with the solving of these troubles when utilising a frequently used calibration method - the Tesa NPL measure instrument. This measuring was implemented by the Czech Metrologic Institute, where the author works; therefore he could take advantage of his rich experience as well as experience of his superiors and colleagues. The author regards the national metrological institute (CMI) as a sufficient guarantee for the hereinafter presented materials, both regarding the professional qualification and from the perspective of formal rightness of this thesis.
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Determining the measurement accuracy of a coordinate measuring machine Zeiss UPMC Carat
Kiška, Roman ; Jankových, Róbert (referee) ; Šrámek, Jan (advisor)
The aim of this diploma thesis is to create a comprehensive study of measurement accuracy of coordinate measuring machine (hereinafter CMM) Zeiss UPMC 850 Carat S-ACC (hereinafter Zeiss Carat) for the needs of the national metrological institute in Brno in accordance with ČSN EN ISO / IEC 17025 and the follow-up system standards of the ČSN EN ISO 10360 series. Additionally, it includes the creation of instructions for the calculation of measurement uncertainty, which will be put into effect in an accredited calibration laboratory. The first part of the work focuses on the description of the current state of knowledge and the definition of basic concepts in the field of metrology and accurate measurements on CMM. The second part describes the Zeiss Carat measuring machine, identifies the individual contributors to the resulting measurement uncertainty and defines the methodology for their quantification. The last part deals with the evaluation of calibration data and the calculation of the expanded measurement uncertainty of the Zeiss Carat instrument, which is used to quantify its accuracy.
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The use of nanofibres strain gauges for construction of linear sensors
Kirchner, Jan ; Kůr, Jan (referee) ; Pernikář, Jiří (advisor)
The aim of this thesis was to determine the basic characteristics of behavior of nanofiber strain gauges and on the basis of experimental measurements to confirm the suitability of the design of the length sensors. There was a product designed with a swivel arm whose rotation burdens the nanofiber strain gauge affixed to the flat side of the cut. Some measurements were carried out to find out a suitable direction of the loading pressure and to reveal the area showing the linear behavior. This linear area is approximately between 44 ÷ 92 % of the range of the nanostrain gauge (0% maximum load tensile, 100% maximum load pressure). Other measurements dealt with temporal stability of the output value at each point. The outcome of these experiments was to determine the methodology and to propose the design of sensors for further tests, the aim of which was to develop a sensor for measuring small diameters (from 1 to 5 mm). K
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Automatic measurement of the motor vehicles distance.
Juřica, Lukáš ; Chmelař, Milan (referee) ; Říčný, Václav (advisor)
This work deals with evaluation of equipment used for non-contact measurement of distance between vehicles. First are discussed various principles of measuring and after the selection of the most appropriate solution is proposed a detailed block diagram of modulation, demodulation and evaluation of the whole system and its mathematical description. Another part is devoted to describing the activities of the microprocessor controller, with which is controlled evaluation part and to the control program. It also analyzes the maximal attainable accuracy of measurement and the errors that affect it. The last part includes a circuit design and simulation of selected functional block, which is a coincidence /quadrature/ detector and construction documents for evaluation and demodulation part of the measurement instrument.
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The Optimal Accuracy of Measurement Assurance in Accordance with Metrological Confirmation
Frank, Petr ; Kocman, Karel (referee) ; Nenadál, Jaroslav (referee) ; Hruška, Karel (advisor)
This thesis deals with the evaluation of accuracy of measurement and achieving the required accuracy level. This includes global analysis of the uncertainty evaluation, the calibration interval design and the creation of confirmation system. Basis of this work is in identification of all possible problems, which may occur during evaluation of accuracy and achieving the required accuracy level. The analysis is followed by suggested solutions for identified problems. It means namely the selection of probability distribution in case of uncertainty type A, evaluation of degrees of freedom in case of uncertainty type B, nonlinear correlation of input values, evaluation of coverage factor, the choice of method for calibration interval design and the procedure for meeting all metrological confirmation requirements. The last part of the thesis is practical measurement and result evaluation in the field of surge protection devices. This chapter demonstrates conclusions from the syntactical part.
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