Izmeritelʹnaâ tehnika

Brief historical information about the creation and development of the Russian Federation standard base in the field of pressure is provided. The results of the analysis of the state and development trends of world metrology in the field of absolute pressure measurements, based on the study of literary data and the results of key comparisons, are briefly presented. The article presents the reasons that led to the development of laser interferometric liquid manometers at the D. I. Mendeleyev Institute for Metrology and their inclusion in the State primary pressure unit standard for the absolute pressure range GET 101-2011. The existing problems of the Russian Federation absolute pressure standard base are analyzed. The purposes are defined and the research results aimed at the accuracy increasing and the expansion of the absolute pressure unit reproduction range are presented. This determines the choice of the GET 101-2011 standard modernization methods: development of a high-resolution laser interferometric oil manometer and of an absolute pressure piston gauge with a set of measuring piston systems. The composition of the modernized GЭT 101-2011 is presented, the design and operating principles of standard installations based on laser interferometric liquid and absolute pressure piston gauges are briefly described, as well as the operating principle of the means for transmitting the pressure unit to secondary and working standards from GET 101-2011 is presented. Results of the research on the improved GЭT 101- 2011 are provided, along with its main metrological characteristics confirmed through state testing. The range of absolute pressure unit reproduction has been expanded to both low and high absolute pressures, spanning from 1·10–2 to 1·107 Pa, the accuracy of unit reproduction is increased by 3–1,5 times in the range from 1·10–1 to 102 Pa, the process of transferring pressure units to secondary and working standards has been improved.

Dielectric characteristics, ferroelectric properties, and phase transition temperatures in thin films of ferroelectric-relaxor barium-strontium niobate Sr 0.6Ba0.4Nb2O6 (SBN60) with a tetragonal tungsten bronze structure deposited on a Si(001) semiconductor substrate have been studied by dielectric spectroscopy methods. The films were grown by high-frequency cathode sputtering technique in an oxygen atmosphere. X-ray diffraction analysis has shown that SBN60 films are single-phase, pure and c-oriented (unit cell parameter c = 0.3932 nm), and according to atomic force microscopy, its surface has a uniform relief, does not contain cavities, pores or other surface defects. An approach is proposed which allows determining the permittivity and its dispersion, the temperatures corresponding to interphase transitions. It is based on measuring the high-frequency capacitance-voltage characteristics of the metal/ SBN60/Si(001) capacitor structure at a fixed temperature (in the range 83–473 K). In particular, it is shown that the Burns temperature in the analyzed thin film is 383 K. The applicability of this approach to the metal-ferroelectric-semiconductor heterostructures properties analyses is discussed.

The problem of input signals recovery is one of the key problems in many branches of science and technology: in measurement technology for dynamic measurements; in control tasks, where the control is based on the input signal (stabilization task); in tasks of image restoration and filtering, etc., which determines the relevance of the development of methods of input signal recovery. The relevance of development of input signal recovery methods is increasing every year and becomes the most pronounced at operation of measuring and control systems in extreme and harsh operating conditions. Non-stationarity and nonlinearity in these conditions are the most pronounced, accounting of which is a prerequisite for the creation of new and improvement of existing information-measuring and control systems. The paper proposes methods for determining the input signal of nonlinear dynamic systems described by the Volterra functional series. The methods are based on the solving of a nonlinear integral equation, which is defined by a finite segment of the Volterra series. The input signal recovery is carried out under the assumption that the integral transforms of Volterra kernels possess factorization based on Borel's theorem, which leads to a nonlinear algebraic equation. Recovery methods of continuous nonlinear dynamic systems described by a finite Volterra series and their discrete analog are considered. When recovering the input signal, for continuous systems the integral Laplace transform is applied, for discrete systems the Z-transform is applied. An example of a mathematical solution to the problem of restoring a discrete one-dimensional signal is given, illustrating the efficiency and effectiveness of the developed methods. The results of studies on restoring signals of nonlinear dynamic systems will be useful to specialists engaged in theoretical research and mathematical modeling in the field of digital signal processing and vector analysis of electrical circuits.

The issue of improving control accuracy for complex mechatronic systems in robotics and precision engineering is examined. The problem of misalignment between the measurement and physical spaces of mechatronic objects has been resolved. This misalignment arises due to manufacturing inaccuracies in mechatronic systems and instability in the sensor characteristics of mechanical actuation systems, among other systematic factors. A method of solving the inverse kinematics problem is proposed that is based on piecewise linear transformation and determining the orientation of the physical space axes using the concept of space separation (i.e. measurement, physical and generalised spaces). The transformation matrix was constructed using the direction cosines of the physical space axes, thereby reducing positioning errors under real-world conditions. An algorithm for correcting the direction cosine matrix, which links coordinates across different spaces, is also presented. Experimental validation was conducted on a monorail tripetron system (“STANKIN”, Russia). A Leica LTD800 laser tracker (Leica Geosystems AG, Switzerland) was used to evaluate positioning errors for both the traditional method (based on an ideal model) and the modified approach that accounts for distortions. The results showed a reduction in total positioning error from 5.69 mm to 3.41 mm (40.1%) across 11 control points. The key advantage of the proposed inverse kinematics solution is its ability to compensate for systematic errors without requiring precise measurement of the mechatronic system’s geometric parameters. These findings can be applied to industrial and collaborative robotics, medical manipulators and other systems where spatial control accuracy is critical. These results contribute to advancing calibration methods for mechatronic systems with non-ideal geometry.

The issues of calibration and performance verification of the planned scientific equipment for the “Sun-Terahertz” space experiment are considered. A blackbody simulator has been developed for ground tests of this scientific equipment. The method of calibration in ground conditions of a blackbody simulator is given. The results of calibrations of the blackbody simulator in ground conditions are necessary to assess the signal level of scientific equipment receivers when measuring radiation fluxes from the Sun during an experiment in low-Earth orbit aboard the International Space Station. Ground tests and testing of the proposed methodology were carried out using a single-channel mock-up of scientific equipment. The blackbody simulator allows you to direct the radiation stream into the telescopes of scientific equipment at various set temperatures of the radiator. A thermal imager based on the MLX90640 infrared camera was used to control the brightness temperature of the blackbody simulator. The proposed technique makes it possible to evaluate factors affecting the operation of scientific equipment, such as the temperature gradient between the surface of the parabolic mirror of the blackbody simulator emitter and the installation point of the thermocouple, the temperature gradient from the center to the edge of the emitting surface of the blackbody simulator and the divergence of the blackbody simulator radiation beam. The spectral transmission coefficient of the air environment in the optical path is also calculated, from the radiator of the blackbody simulator to the entrance window of the receiver of scientific equipment. Based on the results of the experimental verification, conclusions were drawn about the actual radiation fluxes entering the receivers of scientific equipment from a blackbody simulator during calibrations, depending on the temperature set on the meter controller. The results obtained can be used by experimenters involved in thermophysical measurements, spectrometric scientific instruments based on optoacoustic transducers (Golay cell) and other sensitive elements.

Modern research and development in the microwave frequency range require metrological-grade measuring equipment with a dynamic range exceeding 100 dB and the ability to adjust output power. VECTORseries frequency range converter modules for vector network analyzers have been developed and manufactured. The VECTOR frequency range converter modules operate in the following frequency ranges: 50–75; 53.57–78.33; 75–110; 78.33–118.1; 110–170; 118.1–178.4 GHz. The structural diagram of the developed frequency range converter modules is described. The frequency range converter modules provide extension of the upper frequency limit of the vector network analyzer when used for measurements of complex transmission and reflection coefficients (scattering matrix elements) of multiport devices. A vector network analyzer with connected frequency range converter modules forms a unified measurement system. Investigation of the VECTOR-series frequency range converter modules characteristics has shown that the VECTOR modules for frequency ranges 50–75; 75–110; 110–170 GHz have typical output power and operational dynamic range of 15 dBm (31.6 mW) and 125 dB; 11 dBm (12.6 mW) and 120 dB; 1 dBm (1.3 mW) and 110 dB, respectively. The developed frequency range converter modules are compatible with Russian vector network analyzers as well as with foreign counterparts from Rohde&Schwarz GmbH&Co KG (Munich, Germany) and Keysight Technologies (Santa Rosa, USA). A comparative analysis of the presented frequency range converter modules with the modules from Virginia Diodes (Charlottesville, USA), specifically the WR15VNA series, and from Ceyear Technologies, series 3643NA (Qingdao, China), shows that the output power and dynamic range of the developed devices are on par with those of foreign equivalents. The main application areas of vector network analyzers with frequency range converter modules include testing, tuning, and development of various radio frequency devices in industrial production environments and laboratories, including automated measuring stands.

The problem of non-invasive research of the speech apparatus vocal function by the announcer's speech signal is considered. A new method of acoustic analysis of a pulse-type voice source based on a two-stage measurement procedure has been developed. The first stage of measurements provides for filtering the voice excitation signal of the vocal tract, and the second stage – converting this signal into a final pulse sequence synchronous with the main tone of the speech signal. An example of technical (software) implementation of the developed method is considered, estimates of its computational complexity and speed are given. The ability of the method to be used in the soft (with a delay of hundredths of a second) real time mode has been established. A full-scale experiment has been set up and conducted using the author's software. It is shown that at limited intervals of vocalization of the speech signal the developed method guarantees stability of the repetition rate and shape of excitation impulses, which is valuable from the point of view of the accuracy of measurements of all the main parameters of the speech vocal source: from the fundamental frequency to the amplitude disturbances (flickering) of the source pulses. The obtained results will be useful in developing new and upgrading existing algorithms and technologies for speech signal synthesis and digital speech transmission over low-speed communication channels, as well as medical diagnostics and voice therapy systems.

The use of reference materials is the most accessible tool for ensuring metrological traceability of measurement results in various industries, and the main criterion for selecting a reference material is its metrological characteristics, including the uncertainty of the certified value and verified metrological traceability. One of the sources of uncertainty of a reference material is the characterization method selected by the producer. The article describes a method for characterizing a reference material based on the results of an interlaboratory experiment using algorithms from GOST 8.532-2002 “State system for ensuring the uniformity of measurements. Certified reference materials of composition of substances and materials. Interlaboratory metrological certification”, ISO 33405:2024 “Reference materials – Approaches for characterization and assessment of homogeneity and stability” and other documents. The validity of the uncertainty of the certified value of a reference material based on the results of an interlaboratory experiment is analyzed. It is shown that in some cases the above uncertainty of the certified value is significantly lower than the uncertainty of the measurement methods used in the given interlaboratory experiment, and in some cases, it is lower than the uncertainty of the calibrators used, including reference materials. In this case, developers and producers of reference materials have the illusion of high accuracy of reference material characterization by the interlaboratory experiment comparable to methods based on the use of standards. The article describes cases of unreasonable uncertainty underestimation of the certified value of a reference material, for example, due to the so-called “dark uncertainties” of the participants in the interlaboratory experiment, due to the low efficiency of the method of mathematical processing of the interlaboratory experiment results associated with the unreasonable exclusion from the estimation of the certified value of the reference material of the results obtained in certain laboratories, as well as due to the inadequacy of the statistical model underlying the algorithms for processing the results of the interlaboratory experiment to actual experimental data. Various algorithms for estimating the certified value and standard uncertainty from the characterization of a reference material based on the results of an interlaboratory experiment are analyzed. It is shown that the approach proposed by Maurice Cox is effective for estimating the uncertainty from characterization in terms of high resistance to outliers. Based on this approach, the authors of the article have developed their own algorithms that can be used to estimate the commutability of reference materials and for other purposes. In order to increase confidence in the results of determining the metrological characteristics of reference materials in the Russian Federation and to ensure harmonization with international documents, it is recommended to use the Maurice Cox algorithm when revising GOST 8.532-2002.

The mechanism for assessing economic losses from measurement errors is considered and presented. In the study, the evaluation mechanism is understood as a set of methods and tools that determine the procedure for estimating losses from measurement error. The main components of the mechanism are shown – indicators of false positive (error of the second kind) and false negative (error of the first kind) decisions. The term “losses from measurement errors” is used in the current regulatory and methodological document for determining the economic efficiency of metrological activities (MI 2546-99 “GSOEI. Methods for determining the economic efficiency of metrological work”). However, MI 2546-99 does not contain a description of the mechanisms for their assessment, which is a problem for an objective quantitative characteristic of the impact of metrology on the economy. Domestic and foreign regulatory documents and publications are used as sources of scientific data and methods for solving the problem. The results of applying the computer program developed during the research are presented, which are presented in the form of an extended table of limiting values of the parameters of the probability of errors of the first and second kind, as well as in the form of a diagram of their determination in the presence of data on the root-mean-square technological distribution of the measured parameter.A mathematical model for assessing economic losses from measurement errors is formulated and presented in general form, built taking into account the provisions of mathematical statistics and probability theory. The application of indicators of loss reduction from reduction of measurement error in assessing the effectiveness of investment metrological projects is proposed. The results of the study are relevant for developing a methodology for assessing the effectiveness of investment projects that take into account the specifics of metrological activities.

To ensure the reliability of measurements of the content of proteins, fats, moisture and ash in food products and food raw materials, it is necessary to use reference materials similar in composition to the analyzed samples and traceable to measurement standards and / or measurement results of national metrology institutes. The equivalence of measurement results from national metrological institutes should be confirmed in key comparisons. The results of the COOMET 881/RU-a/23 pilot comparisons in the field of measurements of the nutritional value of soy flour conducted in 2024 are presented as a preparatory stage before organizing key comparisons in this field. The national metrology institutes of Russia, the Kyrgyz Republic and China took part in the comparisons. Samples of defatted and semi-defatted soy flour composition with preliminarily studied homogeneity and stability were used as samples for comparisons. The measured characteristics were mass fractions of moisture, nitrogen, protein, crude fat and ash. When carrying out measurements, the participants used measurement methods implemented on standard measurement equipment, as well as primary reference measurement procedures. When assessing the uncertainty, the participants took into account the uncertainty components caused by the following: discrepancy between the results of parallel determinations; rounding of measurement results; direct measurements of quantities included in measurement equations; fulfillment of conditions for achieving constant mass after drying, extraction and ashing; deviation of measurement conditions from optimal values. In comparisons, consistent measurement results for mass fraction of moisture, nitrogen, protein and crude fat with expanded uncertainties (at the coverage rate 2) 0.06–0.12 %, 0.034–0.060 %, 0.19–0.40 %, 0.04–0.08 % respectively were obtained. It is two to eight times higher than the accuracy of standard measurement procedures (methods). The observed discrepant measurement result of the ash mass fraction obtained by one participant in the comparisons is due to the empirical nature of the measured value. In the case of measuring the values of empirical quantities, consistency of results can be achieved by strictly establishing the conditions for performing measurements and the permissible limits of their variation. The comparison results are planned to be used in the preparation of proposals for conducting key comparisons in the field of measuring the nutritional value of soy flour.