Vol 29, No 1 (2021)

Informatics, Computer Science and Control

Development of system-methodological bases to increase the efficiency of foreign economic activities of industrial enterprises

Bataev V.V.


The paper proposes a methodology for analyzing the system of interaction between an industrial enterprise and customs authorities in the process of carrying out foreign trade activities based on the classification and assessment of the system elements functions for performing customs operations and customs control. Foreign economic activity, which is a set of functions of organizations focused on the foreign market in terms of the chosen foreign economic strategy, as well as the forms and methods of work in foreign markets is considered as one of the key factors in the efficiency of an industrial enterprise. Analysis of the foreign economic activity of an industrial enterprise using the developed methodology will make it possible to determine the optimal and cost-effective options for performing customs operations related to the declaration and release of goods in accordance with the declared customs procedure. The focus on large participants of foreign economic activity, which are industrial enterprises, will allow using the results of the study to reduce non-production costs associated with the implementation of foreign trade activities by these enterprises. We have chosen an enterprise of the metallurgical industry that carries out foreign economic activity in cooperation with the customs authorities of the Russian Federation as the object of the system analysis in this research. At the same time the object of analysis is considered as a unified system that has the main system properties: integrity and divisibility, the presence of significant stable links between the elements of the system, the organization and the hierarchical structure of the system, integrative qualities. The object of the research is a complex-structured system of interactions between industrial enterprises that are participants of foreign economic activity and the customs authorities of the Russian Federation. The schemes of interactions of all elements of the four-level hierarchical structure of the analyzed system are illustrated.

Vestnik of Samara State Technical University. Technical Sciences Series. 2021;29(1):6-18
pages 6-18 views

Multi-criteria analysis of resource saving and energy efficiency in the technogenic waste processing system of the oil and gas industry

Derevyanov М.Y., Pleshivtseva Y.E., Afinogentov А.А.


The paper proposes a new approach to multi-criteria analysis of resource and energy saving in the system of processing industrial waste of oil and gas enterprises based on the Data Envelopment Analysis (DEA) method. The DEA method is being extended by the authors to a completely new subject area of extremely important engineering applications related to the problems of processing oil and oily waste.

The basis of the algorithm for analyzing objects of the wastes processing system considered in the article is a new methodology for sequentially solving interrelated problems of multi-factorial comparison of objects according to heterogeneous quality criteria, which differ in new formulations of related problems of mathematical programming.

The developed algorithm for multi-criteria analysis of resource and energy saving in the processing system allows: collecting, classifying and processing information about the objects of the system; assessment and analysis of the resource value of waste in storage, which determines the degree of suitability of waste for use as material resources in processing technologies associated with their recycling and recovery; assessment and analysis of the resource potential of storage facilities and technologies, which determines the efficiency of the secondary use of industrial waste, taking into account their resource value; evaluation and analysis of the resource and energy saving in the system in general.

The partial and generalized indicators of the efficiency of the waste processing system obtained as a result of solving interrelated problems of mathematical programming are analyzed in the decision support system and make it possible to form local control actions on the system or to justify the strategies for managing the waste processing system.

The proposed approach can in the future receive multiple applications in the oil-bearing regions of the Russian Federation, where the growth in the formation of the technogenic waste has serious and often irreversible environmental consequences.

Vestnik of Samara State Technical University. Technical Sciences Series. 2021;29(1):19-35
pages 19-35 views

Research and development of the controller based on the model predictive control

Kolodin A.A., Elshin V.V.


Modern automated process control systems that use programmable logic controllers use software controllers based on the proportional integral-differential control law, the PID controller. In most cases, this regulator is sufficient for conducting the technological process. It has high performance with configurable and sufficient quality of regulation. However, using a PID controller for non-linear, poorly defined, multi-connected objects with a long delay time can lead to unstable control quality indicators, accumulation of errors, and ultimately to a deterioration in product quality. One of the most promising methods of control is Model Predictive Control - MPC. The method base on predictive models of control objects. The quality of the controller's control depends on how well the system dynamics described by the model used to design the controller. In most cases, MPC-based control use to handle optimal control problems on the Manufacturing Execution System-MES. However, thanks to the development of microprocessors and increased CPU performance, it becomes possible to apply the principles of control with a predictive model at a lower level, and perform real-time operational control in optimal modes. The work presents the algorithm of MPC controller. The control object is a SISO object with a nonlinear characteristic and a long transition process. Studies of the developed MPC regulator showed that the quality of regulation, compared to the PID regulator, increased by more than 20%, the time to get to set point decreased, and there was almost no over-regulation. The most effective application of the MPC controller is seen in processes with long transitions and with a significant delay time.

Vestnik of Samara State Technical University. Technical Sciences Series. 2021;29(1):36-45
pages 36-45 views

Virtual tests of robotic vehicle units for virtual commissioning

Orlov S.P., Bizyukova E.E., Iakovleva A.E.


The creation of robotic vehicles for agricultural purposes is a promising direction in the automotive industry. The complexity of the self-driving truck's design, work in difficult operating conditions, and a large number of measuring devices and processing subsystems determine the relevance of creating a virtual test system. These tests are part of the overall virtual commissioning process for a robotic vehicle. The article discusses a set of basic subsystems that provide virtual tests based on a model-based approach: mathematical modeling, measurement modeling, information subsystem with databases, visualization and documentation subsystem. Metrological models of measuring channels for virtual tests have been developed, allowing simulating random vehicle parameter changes. The testing process covers all the most essential components of a robotic vehicle. For example, the article presents a dynamic model of the braking system of a robotic chassis and shows the results of braking modes' virtual tests. The developed virtual test system is used to create a KAMAZ truck as part of a robotic system for agricultural vehicles.

Vestnik of Samara State Technical University. Technical Sciences Series. 2021;29(1):46-57
pages 46-57 views

Structural and parametric synthesis of the control system of the unobserved output for the object with distributed parameters

Tychinin A.A., Tychinina Y.A., Ragazin D.A.


Method of synthesis of a control system for the object with the distributed parametres, providing compensation of dynamic properties of the object and giving to it of properties of standard model of a set. The system possesses the property of an adaptability to parametrical interference of the object. Control along the unobservable coordinate of the object is implemented by synthesizing a chain structure that implements a transfer function close to the inverse transfer function of the object. Weak sensitivity to parametric instability is provided by solving the inverse problem of dynamics. As an example, the heating of a massive billet in a convection oven is considered.

Vestnik of Samara State Technical University. Technical Sciences Series. 2021;29(1):58-72
pages 58-72 views

Integral formulation of solutions of boundary-value problems of heat and mass transfer in domains with moving boundaries

Shevelev V.V.


Using the Fourier transform, integral representations of solutions to boundary value problems of heat conduction and diffusion in a two-phase region with a moving interface are obtained. The proposed approach makes it possible to obtain the equation of motion of the interface without the need to first find the temperature and (or) concentration fields. This makes it possible to study the stability of the interface with respect to disturbances in its shape. The validity of the proposed approach is demonstrated by the example of self-similar growth of a spherical crystal in a supercooled melt and crystallization of the melt on a substrate of the same substance. On the basis of the obtained equation, which determines the rate of self-similar motion of the interface, the features of the kinetics of crystallization of the melt on the substrate are analyzed. The conditions of applicability of the developed approach to the solution of boundary value problems of heat conduction and diffusion in regions separated by a moving boundary are briefly discussed.

Vestnik of Samara State Technical University. Technical Sciences Series. 2021;29(1):73-91
pages 73-91 views

Instrumentation, Metrology and Informative-measurings devices and systems

Wireless sensor network technologies

Likhttsinder B.Y., Bakai Y.O.


The content of this paper is determined by the relevance of wireless sensor network standards. The paper discusses the diversity of wireless networks. Personal wireless network standards are presented. In particular, a detailed analysis of GPRS technology is presented. Various data transmission protocols are presented. Data transmission speeds are briefly reviewed. The evolution of Bluetooth standards is presented. Data transmission rates are described. Standards for Bluetooth technology are discussed in detail, an overview of the advantages and disadvantages of these standards is given, and the variety of applications for wireless sensor networks is presented.

Vestnik of Samara State Technical University. Technical Sciences Series. 2021;29(1):92-103
pages 92-103 views

Electrical Engineering

Research of the control system for liquids level maintenance in tanks

Abakumov A.M., Kuznetsov P.K., Kurgan V.P., Goryachkin A.A.


The problems of controlling the operating modes of pumping units with a frequency-controlled drive based on an asynchronous short-circuited motor are considered. The specific features of the requirements for the control process quality indicators of liquid level stabilization control system for the reservoirs are discussed. Mathematical models of functionally necessary parts of the system are obtained in the form of transfer functions: a frequency-controlled drive with scalar control, a generalized control object, and a feedback sensor. The linearized model of the controlled object taking into consideration a nonlinear dependence of the the torque at the motor shaft on rotational speed is obtained in the form of a transfer function of the aperiodic unit. A block diagram of a closed loop liquid level control system has been developed. It is shown that the use of standard settings for the system under consideration, focused on maximum performance achievement, can leads to unacceptable values of control action speed variations and hence to generation of hydraulic shocks that decreases a wear of kinematic parts of the unit. A method for the synthesis of the controller is proposed, which takes into account the limitations on the quality indicators of the transient process of a speed variation of the pump unit when control system counteracts main disturbances. The synthesis of controller is carried out for an example of a specific installation and the results of modeling transients of a control system and perturbing effects are discussed.

Vestnik of Samara State Technical University. Technical Sciences Series. 2021;29(1):104-119
pages 104-119 views

Method for reducing the amplitudes of higher harmonics in the output voltage of the frequency converter

Starikov A.V., Lisin S.L., Belyaeva O.S., Kirdyashev V.A.


Modern low-voltage frequency converters, built on the principle of stand-alone inverters with pulse-width modulation, have large amplitudes of higher harmonics in the output voltage. This adversely affects the operation of an asynchronous or synchronous motor connected to such a converter, since it causes a decrease in the efficiency of the AC machine. The analysis of the reasons for the poor harmonic composition of the output voltage of traditional inverters with sinusoidal pulse-width modulation is carried out and it is noted that the main one is the introduction of "dead" time when switching half-bridges every modulation period. The proposed method of sinusoidal modulation does not require the introduction of "dead" time. The modes of operation of power transistors with this switching method and control signal diagrams are considered. Analytical expressions are found that make it possible to determine the effective value of the output voltage of the frequency converter and the coefficients of higher harmonics for the proposed method of switching power transistors. The main reason for the low effective value of the phase voltage at the output of the inverter at sinusoidal pulse-width modulation is determined - the ineffective use of the switching period. The proposed method of sinusoidal modulation does not require the introduction of "dead" time, increasing the effective value of the output voltage and reducing the total harmonic component by 75 times. The diagrams of signals that control power transistors and provide a decrease in the amplitudes of higher harmonics at the output of the frequency converter are given. An approximation by the harmonic Fourier series of the output voltage of the inverter, obtained in the case of using the proposed method of switching power transistors, is made. It is noted that for the technical implementation of sinusoidal modulation, which provides small amplitudes of higher harmonics, only two pulse-width modulators are needed.

Vestnik of Samara State Technical University. Technical Sciences Series. 2021;29(1):120-132
pages 120-132 views

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