### INFORMATION TECHNOLOGIES AND SYSTEMS, COMPUTER TECHNIQUE

EFFECT OF ERRORS IN ADJUSTMENT OF QUADRATURE CHANNELS OF A COHERENT SYSTEM ON COMPLEX SIGNAL PARAMETERS ESTIMATION
Sergey I. Ziatdinov, Мичурин С. В.

495

Features of measuring complex signal amplitude and frequency in video frequency range by a system consisting of two quadrature channels are considered. Formulas for fluctuating amplitude and frequency of complex narrow-band random signal are derived with the account for errors in setting the signal processing system. The influence of practically unavoidable amplitude and phase misalignments of quadrature channels is studied. Expressions for errors in measuring parameters of a complex signal in cases of inequality in the transmission coefficients of quadrant channels and deviations of reference voltages from ninety degrees when converting input radio signals to video frequency are presented. Requirements to the quality of tuning of quadrature channels accounting for errors in measuring complex signal amplitude and frequency are determined. It is assumed that the presented results can be used in development and research of coherent signal processing systems.

501

Nonlinear stochastic systems under pulsed input effects forming Poisson flows of events are considered. The process of nonlinear transformation in the system of information represented by time intervals between events is analyzed, and a given nonlinear functional in the Poisson flow intensity function is synthesized. The research is based on the probabilistic time-pulse representation of the Poisson process; the time interval between input events is used as an argument for calculations. An analytical solution to the problem accounting for the exponential distribution of random time intervals characteristic for the simplest Poisson flow is proposed. The algorithm of synthesis of a generalized nonlinear functional given as a table is considered, and formulas for calculating the original function are presented for the case when table data are approximated by power series with negative exponents. The results are confirmed by digital modeling in the Scilab package of applied mathematical programs. The proposed algorithm for configuring a computing device to reproduce a given analytically nonlinear functional can be applied for solution of practical problems in stochastic systems with a Poisson input signal, such as devices using ionizing radiation, queuing systems, etc.

PARAMETERS ESTIMATION OF SINUSOIDAL SIGNAL WITH POWER-LAW FREQUENCY DEPENDENCE
Marina M. Korotina, Aranovskiy Stanislav V., Bobtsov Alexey Alexeevich

507

The problem of estimating parameters of sinusoidal signal whose frequency varying as a polynomial function in time is considered. To solve this problem, a parameterization is proposed that allows formation of linear regression equations with respect to unknown parameters. The desired estimates are obtained using the method of dynamic expansion of the regressor, which ensures the monotony of transient processes. Efficiency of the proposed approach is illustrated by presented results of numerical modeling.

### INSTRUMENTS AND SYSTEMS OF AUTOMATIC CONTROL

SYSTEM OF INSULATION STATUS MONITORING FOR ELECTRIC DRIVES IN NETWORKS WITH A DEAD-EARTH NEUTRAL
Alecksey S. Anuchin , Шпак Д. М., Strzelecki Ryszard , Galina L. Demidova

515

A method for insulation fault detection in variable speed drives operating in TN-networks is proposed. The insulation monitoring system is activated when the electric drive stops. The inverter keys are switched according to a special law, and the leakage current is determined using the current transformer signal, which measures the current in all three phases of the drive simultaneously. The leakage current sensor schematic is considered, and experimental results for various values of insulation resistances are presented. It is shown that the minimum insulation resistance detectable with the method equals approximately to 2 MΩ or lower.

MODELLING ROTATIONS OF SOLAR CELLS ON A SPACE VEHICLE. ADEQUACY CHECK
Овчаренко В. А., Пилецкий А. В., Бурлуцкий С. Г.

522

A mathematical model describing the influence of the main ballistic parameters of an artificial Earth satellite flight on orientation of its solar panels is considered. The model adequacy is checked using a presented test.

MODIFICATION OF THE METHOD OF PARAMETRIC IDENTIFICATION OF A SYNCHRONOUS MACHINE WITH PERMANENT MAGNETS
Teresa Orłowska-Kowalska, Sergey Yu. Lovlin, Madina Tsvetkova, Кононова М. С., Mamatov Alexander G.

528

A modified method of identification of electrical parameters of a servo drive and a PWM inverter, based on the least square method, is proposed. The proposed identification method uses a model that considers the effect of “dead time” and the voltage drop on the power switches of the converter. The method accuracy is improved by separating the identification of the static transmission coefficient and the electromagnetic time constant into two stages, in each of the stages only one parameter is evaluated. The new method is shown to achieve a higher accuracy of parameter estimation compared to existing methods using a linear model of servo drive.

### OPTICAL AND OPTO-ELECTRONIC INSTRUMENTS AND SYSTEMS

RELIABILITY OF ADAPTIVE OPTICAL SYSTEM OF TILT CORRECTION
Alexander V. Chernykh, Yury I. Shanin

538

Laser installation of continuous action is included in an adaptive optical system (AOS) intended for ensuring the required spatial characteristics of the laser beam wave front (WF). The AOS contains two active mirrors: a) the tilt corrector (TC) eliminating the slopes of WF and of the laser beam jitter (corrects about 84 % of WF aberrations), and b) the deformable mirror (DM) eliminating higher orders of the WF aberrations. Control loop of the TC considered in the paper includes tilt corrector, tilt sensor, amplifying unit with a special calculator to generate TC control signals. From the point of view of ensuring dependability in the most difficult conditions, the tilt corrector works. The least dependable in the tilt corrector are piezoelectric actuators subject to cyclic variable electromechanical loads. Technical solutions for control loop of the tilt corrector are analyzed and the reliability requirements are formulated. As a result of the analysis, the critical failures of TC are indicated: reduction in transmitted bandwidth and a loss of compensation ca Надежность адаптивной оптической системы коррекции наклонов 547 ИЗВ. ВУЗОВ. ПРИБОРОСТРОЕНИЕ. 2020. Т. 63, № 6 pabilities. Several issues related to reliability of the AOS elements – drives, TC, control unit, tilt sensor – are considered. A block diagram of the AOS TC is presented and the integrated reliability ratio – the instantaneous operating availability – is evaluated. Reliability of the developed AOC TC elements is confirmed by calculated estimates and presented results of experimental tests of the most critical elements. The developed elements of the control loop TC are shown to meet the imposed requirements.

### TECHNOLOGY OF INSTRUMENT MANUFACTURING

548

Methods of automation of wooden containers design are analyzed. The issues of automated selection of design parameters of type VI boxes according to GOST 5959-80, automated transfer of design parameters to 3D model, and various design documents are considered. Features of building libraries for design using templates are described.

USING STANDARDS FOR DESIGN ESTIMATES OF THE KINEMATIC ERROR OF GEARS
Timofeev Boris P., Abramchuk Mikhail V.

555

A probabilistic approach is applied to determining the accuracy of a gear using the example of tangential composite deviation. Using this approach at the design stage of the mechanism increases the accuracy of predicting the gear quality characteristics. The definition of the tangential composite deviation according to GOST 1643-81 is described, and a formula for calculating the tangential composite deviation function is derived with the account for amplitudes and initial phases of its constituent terms. For probabilistic calculation of the tangential composite deviation, the method of statistical tests – the Monte Carlo method is used. The experiment results are compared with the calculation of the tangential composite Использование стандартов при оценках кинематической погрешности зубчатых передач 561 ИЗВ. ВУЗОВ. ПРИБОРОСТРОЕНИЕ. 2020. Т. 63, № 6 deviation in accordance with GOST 1643-81 for the 5th and 7th degrees of accuracy and for transfer ratios from 1 to 8. Conclusions are drawn about inaccuracies in the notes in GOST 1643 and the possibilities of using the standard.

### SCIENTIFIC AND PRACTICAL DEVELOPMENTS

DERIVATION OF AN ANALYTICAL SOLUTION TO THE PROBLEM OF ANALYZING A CONCENTRATED VIBRATIONAL EFFECT ON A MEMBRANE-STRIP ELEMENT
Tkalich Vera L., Mariia E. Kalinkina, Korobeynikov Anatoliy Grigorievich, Pirozhnikova Olga I.

562

An analytical solution is obtained for the problem on a membrane-strip of infinite length under the action of concentrated unsteady influence. It is supposed that the strip element has a negligible bending stiffness and turns into a membrane element under a concentrated unsteady vibrational effect. In the analysis, the Heaviside function and the Dirac delta function are used. The procedure for calculating the deflection of the membrane-strip in a numerical experiment is implemented using the Maple system. Graphical results of the calculations of the membrane-strip deflection are presented. The proposed approach makes it possible to solve a direct problem on the influence of a given non-stationary action on the membrane strip. The results of calculation carried out for a specific membrane strip are presented in graphical form.

EFFECT OF INTENSIVE PLASTIC DEFORMATION ON THE STRUCTURE AND PROPERTIES OF THE ALUMINUM ALLOY SYSTEM AL-CU-MG
Olga V. Paitova, Elena V. Bobruk, Шашерина С. А.

569

The structure and properties of discs from cast coarse-grained D16 alloy are investigated using optical metallography and transmission electron microscopy, after heat treatment (HT) in traditional modes or exposition to intensive plastic deformation by torsion (IPDT) under pressure of 6 GPa at room temperature. The standard HT modes include: Т4 (hardening at 495°С + natural aging at room temperature for 5 days) and Т6 (hardening at 495°С + artificial aging at 185°С for 10 hours). It is shown that after HT of alloy D16 in T6 and Т4 modes, the grain size decreases by about 4.8 times, and the microhardness increases by 1.6 times, as compared to the initial characteristics. After one or ten revolutions of IPDT, the sizes of structural elements in D16 alloy decreases by 393 and 899 times, and microhardness increases by 2,4 and 2,9 times, respectively.