Vol 24, No 4 (2023)

Articles

Improving the efficiency of the remote sensing satellite radio line

Alatortsev K.V., Alatortsev V.L.

Abstract

With the advent of expanded standards of transfer of information flows (DVBS2X type) from Earth remote sensing spacecraft (remote sensing), there was an opportunity to switch its parameters for transfer of the increased (reduced) data stream to VHSR operating time. For example, switching of modulation and coefficient of interference-immune LDPC (Low Density Parity Check codes) of coding. It allows to reduce power costs for data transmission and to raise the general information flow of data from remote Sensing Satellites (RSS) to Ground Stations (GS) several times. Estimations of theoretically possible transitions to the next transmission mode of data (transition to the level of 0.5-1.5 dB) are made that gives a total gain in increase in a flow of transmitted data can reach 2.0-2.5 times with the possible number of switchings up to 10. In practice, considering the fluctuation nature of the distribution ogtht the signal level during its transmission to Ground Stations, switching is provided in smaller (3-5) number of transitions (at achievement of a power stock 3-5 dB) that leads to a gain in data transmission by 1.5-2.0 times.

RUDN Journal of Engineering Research. 2023;24(4):295-304
pages 295-304 views

Artificial intelligencedriven optimization of MEMS navigation sensors for enhanced user experience

Alizadeh A., Saltykova O.A., Novinzadeh A.B.

Abstract

This review delves into the key area of artificial intelligence (AI)-driven optimization applied to Microelectromechanical Systems (MEMS) navigation sensors, with the primary objective of enhancing the user experience. Employing a comprehensive research methodology, it extensively explores AI-powered techniques, encompassing sensor fusion, adaptive filtering, calibration, compensation, predictive modeling, and energy efficiency. Through rigorous case studies and empirical evidence, this research provides substantial achievements, including enhanced accuracy, reduced power consumption, heightened reliability, and amplified user satisfaction, across diverse applications such as autonomous vehicles, indoor localization, wearable devices, and unmanned systems. In conclusion, this review highlights the transformative potential of AI-driven optimization in MEMS navigation sensors while acknowledging persistent challenges in computational complexity, data availability, and real-time processing. It advocates for future research focusing on innovative AI methodologies, integration with emerging technologies, adherence to human-centric design principles, and the establishment of rigorous evaluation standards. Such research promises to unlock the full potential of AI-driven optimization, ushering in advanced and user-centric navigation systems, and ultimately improving user experience across diverse areas.

RUDN Journal of Engineering Research. 2023;24(4):305-322
pages 305-322 views

Laser thermal hardening of gear wheels manufactured from powder materials

Razin D.A., Pechnikov I.S., Frolov K.A., Lyukhter A.B.

Abstract

It is difficult to imagine modern mechanical engineering without timely and targeted improvement of technological processes, in connection with which new and enhanced traditional methods of manufacturing and processing various types of structures and parts are being developed. One of the ways to reduce the economic costs of machining gears made by traditional methods is the transition to the field of powder metallurgy - powder sintering. This paper presents the possibility of a local increase in the mechanical properties of gears made by powder sintering using laser processing. Laser processing was carried out on a robotic welding and heat strengthening complex, which includes a 6-axis industrial robot, a 2-axis welding positioner, a laser head and a 5 kV ytterbium fiber laser. The high porosity of the sintered material compared to cast billets is a factor limiting the possibility of using laser thermal hardening, as it increases the likelihood of melting the edges of the machined surfaces. The present work is aimed at solving this problem. Before carrying out the experiments, the main quality criteria were identified: “no melting” and “hardening depth”. In the course of a series of experiments on laser thermal hardening, it was possible to significantly increase the hardness of the samples (in the delivered state about 30 HRC), which after processing is in the range from 55 to 65 HRC with a depth of up to 2800 μm on gear teeth made of powder materials. However, open questions remain, which are resolved in performance testing, such as durability and wear.

RUDN Journal of Engineering Research. 2023;24(4):323-330
pages 323-330 views

High-voltage semiconductor voltage pulse generator for capillary discharge formation in soft X-ray radiation source

Samokhvalov A.A., Sergushichev K.A., Eliseev S.I., Smirnov A.A., Timshina M.V., Bronzov T.P.

Abstract

The results of the development of a high-voltage semiconductor voltage generator (based on IGBT transistors) with a pulse transformer and the results of experiments on generating a capillary discharge using it on a compact gas-discharge source capable of generating pulses of soft X-ray radiation (SXR) in the area of the socalled «water window» - with wavelength in the range of 2.4...4.4 nm. Methods for designing a high-voltage pulse voltage pulse generator are described: theoretical calculations and results of modeling the electrical circuit diagram in the LTSpice software package, the developed design of a pulse transformer based on N87 ring ferrites and the generator itself is described, the results of its operation as part of a compact gas-discharge radiation source are presented and analyzed. The prospects of using such a high-voltage generator (with semiconductor transistor switches) with a pulse transformer as part of a soft X-ray radiation source are shown due to its technical and operational features: the developed generator is capable of operating from an alternating current network of 380 V/50 Hz in a frequency-burst mode (with a repetition rate of the generated voltage pulses up to 600 Hz) and charges the capillary capacitance of the SXR source to a voltage of more than 20 kV in a time of about 4 μs, has small dimensions, does not create pulsed high-frequency interference and false alarms, and also has stable output (amplitude-temporary) parameters.

RUDN Journal of Engineering Research. 2023;24(4):331-339
pages 331-339 views

The nested planar central configurations of a trapezoid form in classical and generalized versions of the general (4n+1)-body problem

Perepelkina Y.V., Zadiranov A.N.

Abstract

The study of central configurations, whose concepts and definitions were already formulated by the classics of celestial mechanics - Euler, Lagrange, Laplace and Liouville in the XVIII-XIX centuries, is of interest not only for celestial mechanics, but also for many sections of mathematical analysis, differential equations, analytical mechanics, stellar dynamics and space flight dynamics. In recent decades, there have been opportunities to use the concept of central configurations also in theoretical physics, chemistry, crystallography, etc. We consider planar central configurations, called nested, consisting of polygons sequentially nested one into another, at the vertices of which there are bodies (material points). The existence of nested planar central configurations of trapezoidal type with a sphere in the centre is proved. Early, it was found that abovementioned isolated central configurations exist in the heliocentric rotated coordinate systems. It was supposed only the Newton’s law of attraction is acting between bodies. The Maple software is used to derive the solution of this problem.

RUDN Journal of Engineering Research. 2023;24(4):340-348
pages 340-348 views

The synthesis of structural diagrams of automatic devices on formal neurons

Malinina N.L.

Abstract

The development of finite state machines and the synthesis of neural networks come with enormous computational difficulties. The problems that are faced both by the creators of control finite state machines and the creators of neural networks are almost the same. In order for a control finite state machine to be implemented, an algorithm for its operation must be created, and then a program must be written, and finally this program must be implemented in hardware in the form of a finite state machine. It is crucial to create a finite state machine, which will be deterministic. As for neural networks, it is necessary either to set the weights on its edges with the help of experts, or it must be trained to obtain optimal weights on its edges. Both tasks, that is, the determination of finite state machines and the training of neural networks, are currently most often performed using approximate (exponential or genetic) algorithms. At the same time, few authors point out the fact that, firstly these algorithms give an error of up to 15 %, and secondly the operating time is quite long and requires large energy costs. The article has proven that control finite state machines and neural networks are equivalent based on their structure, which can be represented as a directed edge graph. Such equivalence makes it possible to use methods of normalizing arbitrary graphs to determine finite automata and synthesize neural networks. Methods of graph normalizing are extremely new, they are based on a fundamentally new approach of the extension of graph theory and will allow performing these operations using algorithms that have linear complexity or can significantly reduce the number of options when using brute force.

RUDN Journal of Engineering Research. 2023;24(4):349-364
pages 349-364 views

A study of deflection of rods with different widths using the Taguchi method

Rzayev N.S.

Abstract

The deflection of rods with different widths made of aluminum material was studied using the Taguchi method. The widths of the samples selected for the experiment are 10, 15 and 20 mm, while the applied load is 500, 1000 and 1500 g. The experiments were carried out with the rod in position with one fixed and the other free ends, as well as in position with both free ends. The load was applied to the central point of the rod. The results of the experiment were processed according to the Taguchi L 18 (32×2[1]) plan using the Minitab program. Based on the experimental results, graphs describing the relationship between deflection, load and rod width according to the option of its installation (positioning) are plotted. The study also analysed the results of the experiment. The optimum values of the operated (controlled) deflection parameters were determined to be level 2 ( B ) for placement (positioning) conditions, level 1 for the applied load (500 g) and level 3 (20 mm) for the rod width. According to the results of ANOVA, the main factor affecting the deflection is the load applied to the rod. The relative impact coefficient was 40.12 %. The relative influence coefficient of positioning conditions on deflection was 29.6 8 % and the relative influence coefficient of rod width was 18.30 %. Based on the results of regression analysis, a mathematical model of deflection variation as a function of load and rod width was developed accordingly to the position of rod installation.

RUDN Journal of Engineering Research. 2023;24(4):365-372
pages 365-372 views

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