Vol 15, No 2 (2021)

Articles

Comparative analysis of Russian and foreign regulatory requirements for vibration protection of a tractor operator

Godzhayev Z.A., Godzhayev T.Z., Lyashenko M.V., Shekhovtsov V.V., Iskaliyev A.I.

Abstract

The paper discusses the main requirements of Russian and foreign regulatory documents on vibration protection of the operator's workplace of wheeled and tracked vehicles. Their comparative analysis was performed. The normalization of the parameters of general vibration at the workplaces of operators of tractors and self-propelled agricultural vehicles in our country occurs in accordance with the requirements of SN 2.2.4 / 2.1.8.566-96, GOST 12.1.012-2004 and GOST 12.2.019-2015. The root-mean-square values of vibration accelerations for a certain period of exposure in each octave (one-third octave) frequency band are allocated as the evaluation criteria. They are compared for compliance with the regulated values from a specific standard. At the international level, the object of compliance is the ISO 2631-1: 1997 standard, which establishes the requirements for vertical and horizontal vibration with a certain exposure time on a person from 1 minute to 24 hours in the frequency range from 1 to 80 Hz. The article shows that the most stringent requirements for the level of local vibration are established in the Russian Federation. They provide clear regulation of the type of work performed, duration, magnitude, direction of existing loads, etc. Relatively soft requirements are in most European countries, except Poland, where the MPL is regulated taking into account the age, gender and condition of a person. In addition, in the regulatory documents of most foreign countries there are two and sometimes three indicators: threshold (upper and lower) values and MPL. When the threshold is reached, primary measures are usually initiated to counter harmful factors.
Izvestiya MGTU MAMI. 2021;15(2):2-8
pages 2-8 views

Influence of the cross-sectional shape and length of the compressible sections on the characteristics of a linear peristaltic pump

Grishin A.I.

Abstract

In the overview part of the work, the most common existing designs of pumps of the peristaltic principle of operation, as well as the main areas of their application, are briefly presented. The main part of the work is devoted to the study of the influence on the operation of a peristaltic pump with a linearly arranged tube of the shape of the cross-section of the tube in the region of the compressible sections, as well as the ratio of the sizes of the release elements periodically compressing the pump tube in the transverse direction. The studies were carried out through numerical experiments in the STAR-CCM + program, which is based on the control volume method. As a result of the carried out calculations, it was found that the use of protrusions on the inner surface of the tube gives a positive effect if the protrusions have a special curvilinear shape with a smooth transition near the inner surface of the tube, and the increase in the generated pressure and feed is greater if the protrusions are present only in the compression region tube with the first squeeze element. In this case, the discharge angle of the pump characteristic changes so that a positive effect is not observed in the region of small values of the generated pressure. The study of the influence of different ratios of the lengths of the compressible sections of the tube on the flow and pressure created by the pump showed that for the incomplete compression of the pump tube investigated in the work, the use of squeeze elements of the same length is favorable. Both for a tube without protrusions and for a tube with protrusions, the use of a second squeeze element of greater or lesser length than the length of the remaining squeeze elements with the same total length of all three compressible sections leads to an increase in leakage when the tube is not fully compressed, and thus reduces the pump flow.
Izvestiya MGTU MAMI. 2021;15(2):9-17
pages 9-17 views

Development of methodology for calculation of optimal distribution of electric power between power units of condensing power plant

Ilichev V.Y., Yurik E.A.

Abstract

Optimization methods are used to solve many problems in the field of energy. One of such tasks is the problem of optimal redistribution of power between power units in order to achieve minimum fuel consumption. This is especially important for powerful condensation power plants, where even relatively small fuel savings have significant economic effect. The article is devoted to description of developed method of such optimization, based on the application of differential evolution, which has many advantages over the "classical" methods of optimization. In particular, it was the global rather than the local extremum of the objective function that could be found; it was also easy and powerful to use with modern software. Differential evolution method is organized in the library SciPy of Python programming language, so calculation program was developed in this language to solve the problem. The work considers algorithm and structure of the developed program, as well as the procedure for preparing initial data and calculation process using example of a specific condensing power plant. Modules used in the program to populate the data arrays are mentioned, as well as to output the results in the form of high-quality graphs. With the help of the program, diagram of the optimal redistribution of capacities between power units for any total capacity of the power station is constructed. Also, for entire power range of the power plant, nominal fuel consumption and fuel economy are calculated when implementing the optimal redistribution of capacity in comparison with an even distribution. Obtained software product, available to everyone on the website of the authors, allows not only to study the practical application of differential evolution method, but also to create programs based on it to solve other optimization problems, some of which are mentioned in the article.
Izvestiya MGTU MAMI. 2021;15(2):18-25
pages 18-25 views

Study of the combined drive of the road train

Zuyev S.M., Maleyev R.A., Shmatkov Y.M., Shirokov P.S., Yakhutl' D.R.

Abstract

This article describes purpose, areas of application and main parameters of heavy road trains for the transportation of special and general cargo. Heavy-duty road trains with drive wheels of trailed links are considered. The advantages of using heavy-duty road trains in comparison with single trucks are shown. Additional energy sources for a standard engine (diesel or gas turbine engine for driving a three-phase generator), designed to overcome steep ascents and difficult road sections, are considered. The analysis of the turn of the road train is carried out. The advantages of ring and parallel circuit with individual control are shown. The analysis of the traction forces on the wheels and the spread of losses when turning the road train in a multi-engine drive are made. The traction and dynamic properties of road trains are presented. They characterize the limiting power and kinematic capabilities of road trains in various modes of movement. A search for a rational distribution of currents depending on the forces acting on the wheels and losses in the tires was made. The study of the turning of the vehicle was carried out. The values of currents, the magnitude of the spread of currents and their influence on the efficiency were calculated. The economic characteristics of road trains were determined. A methodology and algorithms for calculating losses and efficiency were developed. An algorithm for calculating at equal currents is presented. Calculations of the efficiency at various speeds and turning radii when the road train is moving are carried out. The analysis of the efficiency at the equality of currents and powers when the speed of movement is changed was made. Various design and technological measures are proposed to improve the technical characteristics of the road train.
Izvestiya MGTU MAMI. 2021;15(2):26-35
pages 26-35 views

Simulation of the insulation monitoring system of the high-voltage electrical network of a vehicle with a hybrid power plant

Malyshev A.N., Grunenkov Y.A., Debelov V.V., Mizin M.D., Kozlovskiy V.N.

Abstract

The paper presents the results of mathematical and simulation modeling, as well as calculated and experimental dependencies, which make it possible to evaluate the operation of the insulation resistance monitoring system of the high-voltage power grid of a hybrid vehicle. The work also provides circuits for measuring insulation resistance, a mathematical model in the MATLAB Simulink environment, and the peculiarities of the operation of the software and hardware simulation complex. The aim of the work is to obtain the most reliable mathematical and physical model of insulation resistance, to determine the architecture of a high voltage battery with the IRM system included in it, to identify the key functions and characteristics of the IRM system, to test the simulation system. The introduction justifies the importance of the IRM system and provides references to standards that govern the requirements for measuring and identifying utility faults. The block diagram of the high voltage battery control system is presented. The composition of its main elements is described. The functions and key characteristics of the IRM system are considered, typical characteristics of insulation monitoring systems are given. A schematic diagram of determining the insulation resistance of conductors and an electric circuit is clearly considered. An equivalent circuit of a differential DC amplifier with a unipolar power supply is presented, which is used to amplify small differential voltages on a shunt when changing large common-mode voltages, which is part of the measuring circuit. Mathematical and simulation modeling was carried out to evaluate the method for calculating the insulation resistance according to the well-known scheme, which is used when measuring using the three-voltmeter method. There was considered the mode of checking the the insulation control system, when several test procedures performed containing simulation of the fault and operating condition of the insulation by connecting and measuring the test resistance. The results of physical simulation of the IRM system and measurement of insulation resistance, voltage between each of the high voltage supply wires and the high voltage battery case, voltage between the wires, battery voltage were obtained. The actual insulation resistance was calculated. The conclusions explain the effectiveness of physical and simulation modeling, obtaining a reliable mathematical model and low error in modeling the insulation characteristics.
Izvestiya MGTU MAMI. 2021;15(2):36-50
pages 36-50 views

Investigation of the components of the cornering resistance of a tracked vehicle on a solid support base

Padalkin B.V.

Abstract

The purpose of the study is to increase the completeness and reliability of approaches to determining the components of the cornering resistance a tracked vehicle, as well as to create a method for their assessment, which will be suitable for practical calculations. The article analyzes two components of the moment of cornering resistance of the tracked vehicle, which can be distinguished if we consider the interaction of the caterpillar with the support base through separate contact spots (active sections of the tracks located under the road wheels). The first component arises from the linear movement of the active sections of the tracks. The second is caused by the rotational movement of the contact patch about the vertical axis. The paper presents a mathematical model of the interaction of the propeller and a dense support base, which makes it possible to study the dependence of the components of the moment of cornering resistance on the geometric parameters of the undercarriage of a tracked vehicle. The horizontal reaction force in this case is presented as a function of the slip coefficient. The possibility of realizing various adhesion qualities of the propulsion unit in the longitudinal and transverse directions of sliding is provided. The model assumes a preliminary division of the contact patch into a finite number of elementary areas. Since the number of elementary sites affects the result, the article conducted a study to determine the minimum number of sites to ensure acceptable accuracy. An analysis of the expressions available in the literature was carried out to determine the specified component of the cornering resistance. The new empirical relationships that better agree with the mathematical model were proposed. The study of several existing tracked vehicles, differing in the mass and size of the track support surface, made it possible to conclude that it is advisable to take into account the moment of cornering resistance of the contact patch for various types of tracked vehicles.
Izvestiya MGTU MAMI. 2021;15(2):51-62
pages 51-62 views

Selection of the characteristics of the suspension system of the high-speed tracked robot

Sarach Y.B., Tkachev Y.A., Krokhin M.E.

Abstract

Currently, the field of mechanical engineering is rapidly developing, including the creation of robotic high-speed vehicles. The design of suspension systems for such vehicles must be accompanied by the fulfillment of certain requirements, which are currently not formulated. Considering the thing that there is no person in the body of a high-speed robot, the application of the requirements for the suspensions of crew vehicles is not justified. In order to develop recommendations on the choice of characteristics of suspension systems for high-speed tracked robots, the research objects, which mass is in the range from 1000 to 10000 kg are determined. No suspension system is required for objects weighing less than 1000 kg. Objects weighing more than 10,000 kg will be created on the basis of existing serial vehicles. The study is based on the provision that the considered class of vehicles is not subject to restrictions on the range of natural frequencies of body vibrations. Considering that one of the main requirements remains for high-speed tracked robots - ensuring a high average speed, it is proposed to increase the suspension stiffness in order to exclude resonance from the range of possible travel speeds. Using the accepted provisions, a study of the suspension system of increased stiffness is carried out. The movement along the tracks of a harmonic profile in resonance mode and a broken dirt road is simulated. The results of the study show that the characteristics of the suspension system, selected according to the proposed method, make it possible to move along the line of the harmonic profile in the resonant mode without suspension breakdowns. The speed of movement on a broken dirt road is limited to a value, which exceeding leads to significant vibrations of the body and an increase in the load on the elements of the suspension system. The absence of breakdowns leads to a decrease in the loading of the suspension, which makes it possible to reduce the mass of its elements.
Izvestiya MGTU MAMI. 2021;15(2):63-70
pages 63-70 views

Optimization of transient processes of the pneumatic servo drive taking into account the friction model with the Stribeck effect

Kireyeva V.A., Trukhanov K.A.

Abstract

The aim of the work is to select the optimal values of the parameters of the digital PID controller to eliminate self-oscillations in systems, as well as to optimize the type of transient processes of the servo pneumatic drive. The reason for the study was the problem of the occurrence of self-oscillations in pneumatic systems when using friction models that are closest to reality. The scientific novelty of the article consists in the creation of a computer model and the application of optimization methods to improve the quality of transient processes of the pneumatic servo drive, taking into account the Striebeck friction model. The authors of the article optimized the transient processes of the pneumatic servo drive taking into account the selected friction model. The optimal parameters of the PID controller were selected using computer simulation. And the instability of the system was eliminated as well. To optimize the system performance, the gradient descent method was chosen. An assessment of the quality indicators of transient processes before and after optimization was made. Based on the simulation results of the pneumatic servo drive system, it can be concluded that the gradient descent method can be used to determine the parameters of the PID controller. The transition from an analog (continuous) system to a digital (discrete) system has been made It is necessary to determine the sampling period for its implementation. The article indicates the main methods for determining the sampling period and shows the disadvantages of these methods. Analysis of the results shows that the methods described in the article should be used only for the first approximation, and the value of the indicated quantity should be selected from the calculation of the minimum error between an analog (continuous) and digital (discrete) system. An error of less than 1% allows the selection of a programmable logic controller. The topic of the article is relevant for scientific research and includes the provision of practical recommendations for determining the parameters of a digital PID controller and selecting a controller for specialists who are inloved in the design of systems that include a pneumatic servo drive.
Izvestiya MGTU MAMI. 2021;15(2):71-80
pages 71-80 views

Study of suspension systems for experimental tanks of the USSR in the second half of the 20th century

Tsipilev A.A., Nakaznoy O.A.

Abstract

Modern pneumohydraulic suspension systems for high-speed tracked vehicles have fairly typical versions of kinematic schemes, implying the installation of an elastic-damping element directly on the suspension housing (inside or outside). This solution is structurally relatively simple, and it is understood that it allows to reduce the values of unsprung masses. Other options, with placement of elastic and damping elements inside the guide elements (balancers), did not “take root” due to the greater structural complexity of both elastic or damping element and the suspension guide element. In addition to the structural complexity of implementation, such a solution increases the values of unsprung masses and, most importantly, complicates the organization of the cooling system. The protruding elements of the chassis are clogged with soil, snow (mud) when driving, which acts as a heat insulator. Nevertheless, with modern technological capabilities, these difficulties can be overcome to a certain extent, in whole or in part. However, despite the above disadvantages, this solution also has important advantages: the suspension does not take up space in the reserved volume, but is completely inside the tracked bypass, which allows using the housing volume more efficiently, and, in addition, providing the most successful bottom design for protection from mine detonation (in the case of a heavy tank “Object 279”, this also made it possible to significantly increase the cross-country ability). This article provides an overview of Soviet prototypes of heavy and rocket tanks, which suspension system was implemented in the guide element. The article also presents a method for determining the power and kinematic transfer functions for these suspension options, analyzes the design implementations and shows that the characteristics of the elastic elements of experimental vehicles meet modern requirements for the suspensions of high-speed tracked vehicles.
Izvestiya MGTU MAMI. 2021;15(2):81-92
pages 81-92 views

Algorithm of anti-lock braking system for two-axle vehicles with one driving axle with adaptive redistribution of braking forces

Zhileykin M.M., Chugunov D.S.

Abstract

The main purpose of active vehicle safety systems is to prevent an emergency situation. If such a situation arises, the system independently (without the participation of the driver) assesses the probable danger and, if necessary, prevents it by actively intervening in the driving process. One of the ways to increase the active safety of vehicles when braking is the use of anti-lock braking systems (ABS). The main problems in ensuring the operation of the ABS, built on different control principles and with different control parameters, are the impossibility of directly determining the vehicle speed and, as a result, the slip coefficient, as well as the inability to effectively respond to changing road conditions during braking. For example, when braking on a slippery supporting surface and trying to avoid an obstacle in front, there is a risk of losing traction and skidding. The algorithms of the ABS operation developed at present do not ensure the prevention of the occurrence and development of skidding under the conditions indicated above. The aim of the work is to increase the stability and controllability of two-axle vehicles with one driving axle during braking due to the adaptive redistribution of braking forces on the wheels. An algorithm for the operation of an anti-lock braking system with adaptive redistribution of braking forces on the wheels of a vehicle is proposed. Thanks to this algorithm, when braking on a slippery surface of a two-axle vehicle with one driving axle, the absence of wheel blocking and also skid resistance are ensured. The efficiency and effectiveness of the proposed algorithm when braking a two-axle vehicle with one driving axle on a slippery supporting surface were proved by the methods of simulation.
Izvestiya MGTU MAMI. 2021;15(2):93-100
pages 93-100 views

The issue of improving the efficiency of nitrogen oxide neutralization systems in diesel internal combustion engines

Shabanov A.V., Kondratiev D.V., Vanin V.K., Dunin A.Y.

Abstract

The most effective method of reducing nitrogen oxides in diesel exhaust gas is selective purification by the SCR-NH3 method. The method uses ammonia released during thermolysis and hydrolysis of a urea solution when it is injected through a nozzle into a neutralizer. This method has a relatively low efficiency of cleaning the exhaust gas from nitrogen oxides. The main factor hindering the achievement of high efficiency of the NOx neutralization system is the insufficiently high temperature during the implementation of this process. The article analyzes various ways to increase the efficiency of the neutralization process and proposes a new method for neutralizing NOx by using urea injection into the cylinders of the internal combustion engine at the expansion stroke in a diesel internal combustion engine. Efficiency can be achieved due to a higher exhaust gas temperature in the cylinder of the internal combustion engine and an increase in the time of the process of thermolysis and hydrolysis of urea. The kinetics of the decomposition of nitrogen oxides, the process of NH3 oxidation, and the calculation of temperature conditions in the cylinder of a diesel internal combustion engine at the exhaust cycle are considered. The experience of neutralization of NOx contained in the flue gases of thermal power plants, where NOx purification takes place at high temperatures without the use of a catalyst, is analyzed. It is shown that the modernization of the SCR-NH3 process, due to the injection of urea at the exhaust stroke in a diesel internal combustion engine, will simplify the existing method of NOx neutralization and at the same time obtain additional advantages for a modern high-speed engine.
Izvestiya MGTU MAMI. 2021;15(2):101-112
pages 101-112 views

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