No. 11

Prospects for the application of test harmonic equal-amplitude series with a band spectrum in frequency response meters of narrow-band filters

The paper presents a new method for generating test signals of equal-amplitude harmonic series in frequency response (FR) meters of filters in the audio and infrasonic ranges. The expediency of replacing narrow-band filters of a signal with a rectangular spectrum in the low-frequency region – a cosine equal-amplitude series (CEAS) – with cosine or sine series with a rectangular spectrum limited from below is shown when analyzing the frequency response. The dependences of the distortions of the uniformity of the spectra of limited series, caused by quantization, on the bit depth of the digital-to-analog converter (DAC) are investigated. The reduction in distortion when replacing the cosine series with one of the limited series with a fixed DAC bit depth, as well as possible reductions in bit depth with fixed permissible uniformity distortions, are estimated.

Keywords: narrow band filter, automated measurement, frequency responses measurement, sound range, infrasound range, test signal, Dirichlet kernel, equal-amplitude harmonic series, rectangular spectrum, band spectrum.

Analytical models for goose message transmission in packet-switched networks of power supply systems

The authors have derived the formulas to estimate the average waiting time for packets at nodes in a packet-switched network under the influence of external and internal traffic flows. The program assesses the accuracy of the proposed analytical methods for the equivalent transformation of flows and service time characteristics of packets at network nodes. We have compared the results of analytical and simulation modeling of packet transmission processes, categorized by urgency, under varying load conditions in the transmission channels of the power supply system. The study results showed that the error in calculating the average packet transmission time in the data transmission channels of digital substation networks does not exceed 15 %. This level of accuracy is sufficient for engineering calculations. Authors note that the direct application of methods from intermediate queuing theory with Poisson flow approximation leads to errors exceeding 60 %. The developed analytical tools are for multi-scenario analysis of the temporal characteristics of packet-switched computer networks and serve as fundamental tools in developing algorithms for distributing prioritized heterogeneous traffic in integrated service computer networks.

Keywords: computer networks, packet switching, priorities, transmission time, analytical models, flow transformation, recursive relations, factor space, calculation errors.

Automated decision support system software with promptly updated logic

The article considers one of the options for solving the problem of promptly changing the logic of the decision support system of the crew (operator) of a highly maneuverable multifunctional aircraft without the need to change the on-board system software during operation. The task is solved by transferring the logic of the system to external files, while specialized modules-external file handlers should be provided in the on-board software. The structure of the on-board software and brief requirements for software modules-processors of external files of such a system are presented. The process of developing updatable system files is analyzed and the need for the development of a computer-aided design system is determined to reduce the complexity of developing updatable logic files for the decision support system.

Keywords: knowledge base, expert system, life cycle, data update, artificial intelligence, aircraft, computer-aided design system.

Investigation of self-oscillations in nonlinear multiplicative type systems

The problem of studying self-oscillations in dynamical systems of arbitrary order with nonlinear interaction of multiplicative type processes is considered. Based on the developed block diagram of this class of nonlinear systems, a methodology for finding the conditions for the occurrence of self-oscillations and determining their parameters is proposed. An example is given with a comparative assessment of the results of studying self-oscillations in a multiplicative system obtained using the developed methodology and digital modeling.

Keywords: multiplicative system, nonlinear interaction, Cauchy system, harmonic balance method, self-oscillations, periodic process.

Road traffic assessment using neural networks

The issues of road traffic intensity assessment using neural network object recognition methods are considered. The developed algorithm and its program implementation allow to estimate the number of cars of different types that passed through a road cross section in a given time period using a video record of traffic flow. The road traffic digital model is created. Developed model acts as the basis for creating a transport infrastructure facilities air pollution modeling system. The results and methods of this research may be useful tool in combating air pollution and improving the people life quality for environmental organizations and agencies.

Keywords: neural networks, traffic intensity, road traffic, metrological characteristics, measurement experiment, digital model.

Adaptive control modes and control systems for in-chamber manipulators

The paper presents new approaches to the structure of control systems for electromechanical radiation-resistant manipulators designed for operation inside sealed chambers at the enterprises of the Rosatom State Corporation. An algorithm for the formation of safety zones (zones of geometric restrictions) inside sealed chambers and an algorithm for implementing restrictions on the movement of the manipulator when approaching the boundaries of the safety zone have been synthesized.

Keywords: arm manipulator, sealed chamber, geometric constraints, triangulation.

An unmanned bionic underwater vehicle for monitoring natural and man-made objects in the hydrosphere

The study of unmanned underwater vehicles for oceanographic research has been carried out. An original design of a bionic unmanned underwater vehicle is proposed, which uses a parallel mechanism to control the position of the caudal fin. The structure of the underwater vehicle control system is proposed. The proposed design of the underwater vehicle made it possible to use various types of swimming, for example, vertical, like a tuna, and horizontal, like a dolphin.

Keywords: unmanned underwater vehicle, bionic principles of motion, loading and surfacing control, navigation, tail thruster, actuator.

Technology and equipment for forming an edge profile in the manufacture of CdZnTe substrates with a diameter of up to 55 mm

The work is devoted to the formation of the edge profile of CdZnTe substrates, carried out in order to increase the strength and reduce the risk of mechanical damage to the substrates in subsequent lapping/polishing operations, which increases the yield of suitable products not only at the current operation, but also at subsequent stages of production. This production operation is carried out on a modern substrate edge processing machine KROM-5 with a diameter accuracy of 0.05 mm. A technology for forming an edge profile using the specified equipment has been developed, and more than 50 CdZnTe, GaAs, InSb and GaSb wafers with a diameter of ≤ 55 mm have been processed, ensuring a yield close to 100 %.

Keywords: mechanical rounding, CdZnTe, edging machine.