Вісники та науково-технічні збірники, журнали
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Item Удосконалення структурних методів коригування адитивних похибок калібраторів напруги постійного струму(Видавництво Львівської політехніки, 2016) Матвіїв, Роман; Національний університет “Львівська політехніка”Вдосконалено метод коригування адитивних складових похибок на основі комутаційного інвертування в калібраторах напруги постійного струму з елементами аналогової пам’яті комутаційних двополярних сигналів. Спроектовано структурну схему і принципові схеми окремих вузлів калібратора напруги з автоматичним коригуванням адитивних похибок і проведено їх дослідження. Усовершенствован метод коррекции аддитивных составляющих погрешности на основе коммутационного инвертирования в калибраторах напряжения постоянного тока с элементами аналоговой памяти коммутационных двуполярных сигналов. Спроектирована структурная схема и принципиальные схемы отдельных узлов калибратора напряжения с автоматической коррекцией аддитивных погрешностей и проведены их исследования. In normal operating conditions the error correction is usually conducted shifting the transformation function of DC voltage calibrators by introducing a corrective quantity equal in value and opposite in sign to additive error. This additive error correction is performed in manual and automatic modes. Additive errors of DC voltage calibrators are mainly caused by zero bias of the transformation function of analog electronic components in electronic circuit and voltage drop in communication lines between different circuit nodes. The additive errors caused by the operational amplifier equivalent offset voltage, are added to the output voltage of DC voltage calibrator and converted into multiplicative errors through the use of code-control dividers. Additive errors of the output scale converters of DC voltage calibrators cause additive offset of output voltage. In addition, they can also occur during the passage of supply current of different device units through the common communication lines between them. The structural and technological methods are used to reduce these errors. The review of additive error adjusting methods by means of inverting switching is conducted. Therefore, to use the additive error adjusting methods in DC voltage calibrator it is necessary to conduct their research and improvement. The method of additive error adjusting based by means of inverting switching DC voltage calibrator with analog memory elements of switching bipolar signals is improved. The block diagram of the DC voltage calibrator with double inversion is analyzed. The graphics dependences of additive error for different values of frequency clock generator, time delay and transmission rate of code-controlled divider are considered. The dependences of output voltage error value from the output signals delay formation are also investigated. Based on the analysis shows that the main drawback to switching-inverting method is the effect of forming precision pulse control keys and signals delay formation arising from the lack of speed switching transients and key operational amplifiers and code-controlled divider. To eliminate the influence of outputs transients proposed output elements of operational amplifier are stored in analog memory. A structural diagram output of DC voltage calibrator with analog memory elements. A description of scheme and given equation output voltage. From these equations shows that the resulting delay from switching the input and output signals create multiplicative error on frequency clock generator and time value delay. Under this factor of multiplicative error can be adjusted change in transmission kodecontrolled divider for a clock frequency generator of value. Improved principle scheme of separate units DC voltage calibrator with automatic errors correction and conducted its investigation and presented graphic dependences of the output voltage changes of the combiner. Analysis of graphical dependences shows that amplitude of the variable component of combiner output depends on the time constant memory elements and adder. When τ = 18 ms value variable component equal to 0.25 mV at a clock generator frequency of 1000 Hz and 0.5 mV at a frequency of 500 Hz. To reduce the variable component of the voltage at the output combiner is applied passive filter on condenser C3 and active at operational amplifier DA2. Accordingly, for the variable component value less than 1 mVmust apply suppression filter coefficient K = 47 dB at a clock generator frequency of 1000 Hz and K = 54 dB at a frequency of 500Hz. Computer research determined that the applied filter reduces a variable component not exceed to 1 mV. The proposed method of component additive error correction DC voltage calibrator from inverting switching voltage source model and output amplifier with switching signal analog memory elements output amplifier completely component additive errors corrects and improves dynamic performance DC voltage calibrator.Item Оцінювання стандартної непевності типу “В” на основі складових адитивної та мультиплікативної похибок(Видавництво Львівської політехніки, 2015) Васілевський, ОлександрЗапропоновано спосіб перерахунку адитивної та мультиплікативної складових похибок, аналітичні вирази яких отримуються розкладанням відповідного рівняння перетворення у ряд Тейлора, в стандартну непевність типу В. Цей спосіб апробовано під час оцінювання статичних характеристик засобу вимірювання кутової швидкості. Він дає змогу представляти характеристики точності засобів вимірювань відповідно до вимог міжнародних стандартів з оцінювання якості вимірювань. Предложен способ пересчета аддитивной и мультипликативной составляющих погрешностей, аналитические выражения которых получают путем разложения соответствующего уравнения преобразования в ряд Тейлора, в стандартную неопределенность типа В. Этот способ апробирован при оценке статических характеристик средства измерения угловой скорости. Он позволяет представлять характеристики точности средств измерений в соответствии с требованиями международных стандартов по оценке качества измерений. A method for conversion additive and multiplicative constituents of errors, analytical expressions are obtained by decomposition of the corresponding transformation equations in Taylor series in a standard uncertainty of type B. Decomposition of transformation equations used means of measuring in the Taylor series allows to obtain analytical expressions of basic static characteristics of the means of measuring on the basis of which it is possible to explore the characteristics of changes in the sensitivity of means of measuring, the nominal conversion function, influencing coefficients, additive and multiplicative errors in a deviation of influencing parameters on their nominal values. This method has been tested in the evaluation of static characteristics of measuring angular velocity. It allows you to represent the characteristics of precision of means of measurements in accordance with the requirements of international standards to assess the quality of measurements. These mathematical expressions allow investigation of basic metrological characteristics of a measuring angular velocity, and the causes and conditions that lead to increased measurement errors in the angular velocity of electric motors to be identified. To represent standard uncertainty of type B, which is caused by the presence of additive and multiplicative errors in the measurement means, mathematical expressions are proposed that allow recalculation of these errors to standard uncertainty. The mathematical expressions were tested using the example of the recalculation of additive and multiplicative errors of the measurement means of the torque in the standard uncertainty of type B. The resulting mathematical tools and characteristics of change of the basic static metrological measuring means for angular velocity give us the opportunity to identify the causes of increase in error in the measurement of angular velocity in electric motors. This enables us to explore how to diminish or eliminate them, and also to synthesise measuring means angular velocity with standardised metrological characteristics. To convert received instrumental error components measuring angular velocity in a standard uncertainty of type B and presentation characteristics of precision measuring instruments in accordance with the requirements of international standards to assess the quality of measurements suggested model equations given in the article. On the basis of the proposed model equations executed counts additive and multiplicative error components measuring the angular speed of the combined standard uncertainty of type B, which is caused by the presence of the instrumental components of errors in deviation vlyayuschih magnitude of its nominal value. The studies found that the type B standard uncertainty is 3.38 rad/s in the range of conversion from 0 to 100 rad/s rejecting influence quantity β from its nominal value of 0.01 radians.