No 4 (2020)

Articles

Evaluation of indicators of curvilinear movement of a road train using mathematical simulation

Gorelov V.A., Yevseyev K.B., Chudakov O.I., Balkovskiy K.S.

Abstract

Introduction: a widespread approach to the transportation of large-sized and heavy-weight indivisible cargo on roads and terrain is the use of multi-axle wheeled transport complexes, which are road trains. At the same time, due to the significant overall dimensions, one of the most important properties of such machines is agility, that is, the ability to move along a trajectory of large curvature in a limited area, which is especially important in loading / unloading zones. Subject of research: the article presents an approach to predicting the indicators of curvilinear movement of multi-axle wheeled road trains, based on the application of the method of mathematical modeling of the dynamics of body systems. Methodology and methods: the essence of the method is to create a mathematical model of the movement of a road train, represented by a system of rigid bodies, which are interconnected by kinematic and power connections. The simulation model developed within the framework of the study makes it possible to take into account with high accuracy the peculiarities of the interaction of the wheel propeller with the supporting surface, the redistribution of normal reactions between the support modules, as well as the force factors arising in the coupling device and ensuring the interaction between the tractive vehicle and the trailer link. The mathematical description of the interaction of the propeller with the ground is based on the concept of “friction ellipse”. Using the presented model, an assessment of the turnability of a wheeled road train equipped with a trailed link with swivel and non-swivel wheels was carried out. The required width along the tracks of the outer (running in) and inner (lagging) wheels was used as an assessment criterion. To assess the feasibility of using a trailed link with fully steered wheels and, accordingly, complicating the design of the machine, an additional assessment of the required power of the steering drive was carried out. Results and scientific novelty: a mathematical model of the dynamics of a road train was developed. It makes possible to predict with high accuracy the indicators of curvilinear movement of wheeled vehicles, as well as to estimate the required power of the steering drive. Practical significance: a mathematical model of road train movement was developed, which allows a wide range of tests to be carried out to assess not only the indicators of curved-linear movement, but also the mobility of wheeled vehicles of any configuration as a whole.
Izvestiya MGTU MAMI. 2020;(4):2-16
pages 2-16 views

Improving the operational efficiency of the linear type peristaltic pump

Grishin A.I.

Abstract

The paper investigates the effect on the linear peristaltic pump operation of the properties of the material of its elastic tube, the algorithm of actuation of the release elements, as well as the presence of irregularities in the inlet and outlet sections of the pump in the form of alternating confusers and sudden expansions. To study the influence of these factors, a series of numerical experiments was carried out using the universal software STAR-CCM +, where the pump operation was simulated by a joint calculation of the fluid flow and elastic deformations of its tube. As a result of numerical experiments for a number of values of Poisson's ratio, it was found that the material of the pump tube must be selected with the lowest possible Poisson's ratio in order to obtain the highest efficiency. The study of possible algorithms for the actuation of the release elements of the pump showed that in order to obtain the maximum efficiency, the pump operation mode should be selected in accordance with the drive design. The drive, where energy is expended only on the movement of the release elements, requires the mode with the first release elements to hold the tube in a compressed state longer, which provides a higher feed value. For the drive, where energy is spent on maintaining the tube in a compressed state, the preferred mode is the one with the delay in the return of the release element to its original state is minimal. As a result of studying the influence of sections with irregularities, it was found that the use of the height and pitch of irregularities, when the ratio of the resistances of these sections in the forward and reverse flow is optimal, leads to a decrease in the flow and pressure of pump.
Izvestiya MGTU MAMI. 2020;(4):17-26
pages 17-26 views

Preliminary synthesis of algorithms for automatic control of automobile continuously variable transmissions with flexible links

Yesakov A.E., Kretov A.V., Krasavin P.A.

Abstract

Variators of different operating principles and designs are of interest as components of automatic transmissions for ground transport and traction machines. At the same time, one of the most popular types of variators are the variators built on the basis of continuously variable transmissions with flexible links. The main reasons for the use of such variators in the transmissions of a number of modern passenger vehicles are, on the one hand, the emergence of flexible link designs with high durability, and, on the other hand, the widespread introduction of programmable electronic devices into automatic control systems for continuously variable transmissions. A direct consequence of the latter circumstance was the need for in-depth research aimed at synthesizing such control algorithms that would make it possible to fully use the advantages inherent in continuously variable transmissions with flexible links and minimize the operational consequences of their shortcomings. This paper makes an attempt to solve the problem of synthesizing the algorithm in a preliminary form, based on the goal of providing the vehicle with the best traction and speed properties. The presence of such an attempt will allow, having set the main parameters of a continuously variable transmission for some reason, to develop the hardware of the automatic control system. In turn, this will make it possible to synthesize a refined algorithm that takes into account the dynamics of the system, errors of meters and signal conversion devices, as well as other factors affecting work processes. When considering the described problem, various variants of the geometry of the contact surfaces of the continuously variable transmission links were taken into account and the corresponding mathematical apparatus were formed. The results of calculations, obtained by computer program that implements these devices, are selectively presented in the materials of the paper.
Izvestiya MGTU MAMI. 2020;(4):27-40
pages 27-40 views

Reduced rutting of wide-grip sprinklers

Zhuravleva L.A., Tkhuan N.V.

Abstract

During the process of irrigation, when moving sprinklers across the field, the wheels of the running supports create a track. As the number of passes increases, so does the depth of the track. At the end of the irrigation season, it can reach 0.3-0.45 m, lead to slipping wheels and excessive watering. The intensity of the process of rutting and reducing the coupling properties of the running systems of sprinkler machines is further increased in the presence of free, not absorbed water, causing the formation of runoff on the track. The greatest depth of the track by the end of the season in the last undercarriages occurs due to the increase in the intensity of irrigation and the diameter of the drops of sprinklers located at the end of the pipeline. The choice of running systems should be made taking into account the characteristics of irrigated surfaces, rational ratios of span lengths, diameters of pipelines and sprinkler arrangement schemes. The aim of the study is to consider the impact of the irrigation process on the bearing properties of the soil and the formation of a track. The article presents theoretical dependences for determining the depth and width of the track for two-wheeled and three-wheeled undercarriages of wide-grip sprinkler machines. Field studies were conducted on “Kuban-LK1M” (Cascade) and “CASCADE” sprinkler machines. The article presents the dependence of the track depth on the number of the undercarriages with a soil bearing capacity of 110-125 kPa. The research made it possible to determine the approximate zones of application of wheel systems, depending on the bearing capacity of the soil. Analysis of the data shows that it is advisable to equip sprinklers with narrow pneumatic wheels on soils of increased strength. On soils with low bearing capacity and significant irrigation rates from 600 m3 / ha - wide-profile pneumatic tires 18-24; 23-26, 21.3-24 for “Kuban-LK1”, “Kuban-LK1M” (KASKAD), KASKAD with a profile width of 0.30-0.54 m, including the installation of wider tires at the end part of the machines. In addition, in conditions of low soil strength, it is possible to use tires on sprinklers with smaller profile widths than the recommended ones, but for reduced span lengths or a reduced diameter of the water pipeline.
Izvestiya MGTU MAMI. 2020;(4):41-49
pages 41-49 views

Model of the dynamics of a wheeled vehicle for a complex of full-scale-mathematical modeling

Kositsyn B.B.

Abstract

Introduction. The use of the method of full-scale-mathematical modeling in “real time” opens up wide opportunities associated with the analysis of the modes of operation of the “man - vehicle - environment” system, as well as the study of the loading of units and assemblies of vehicles. The existing research complexes of full-scale mathematical modeling are suitable for obtaining most of the indicators usually determined by full-scale tests. The difference lies in the ability to fully control the course of virtual testing, recording any parameters of the vehicle movement, taking into account the “human factor”, as well as complete safety of the experiment. Purpose of research. The purpose of this work is to create a mathematical model of the dynamics of a wheeled vehicle, suitable for use in such a complex of full-scale mathematical modeling and assessment of the load of transmission units in conditions close to real operation. Methodology and methods. The proposed model is based on the existing model of the dynamics of a wheeled vehicle developed at Bauman Moscow State Technical University. Within the framework of the model, the dynamics of a vehicle is described as a plane motion of a rigid body in a horizontal plane. The principle of possible displacements is applied to determine the normal reactions of the bearing surface. The interaction of the wheel with the ground in the plane of the support base is described using an approach based on the “friction ellipse” concept. To enable the driver and operator of the full-scale mathematical modeling complex to drive a virtual vehicle in “real time” mode, the mathematical model is supplemented with a control system that communicates between the control parameter set by the driver by pressing the accelerator and brake pedals and the control actions of the vehicle's transmission units, such as: an electric machine, an internal combustion engine, a hydrodynamic retarder and a brake system. The article presents a block diagram of the developed control algorithm, as well as approbation of the system's operation in a complex of full-scale mathematical modeling. Results and scientific novelty. A mathematical model of the dynamics of a wheeled vehicle was developed. It opens up wide possibilities for studying the modes of operation of the “driver-vehicle-environment” system in “real time”, using a complex of full-scale mathematical modeling. Practical significance. A mathematical model of the dynamics of a wheeled vehicle was developed. It is supplemented with an algorithm for the distribution of traction / braking torques between the transmission units, which provide a connection between the driver's pressing on the accelerator / brake pedal and the control parameters of each of the units.
Izvestiya MGTU MAMI. 2020;(4):50-64
pages 50-64 views

Volumetric hydraulic drive with series connection of hydraulic actuators

Pil'gunov V.N., Yefremova K.D.

Abstract

The aim of the proposed work is theoretical and experimental studies of the performance of a single-channel hydraulic drive with a series connection of executive hydraulic cylinders and the development of recommendations for predicting their characteristics. The authors of the paper carried out a set of experimental studies and obtained the numerical kinematic, speed and power characteristics of a single-channel hydraulic drive with five hydraulic cylinders connected in series. It is shown that the nature of the kinematic connection is determined by the differentiation of the hydraulic cylinders. The speed of advancement of the piston of an individual hydraulic cylinder is determined by its serial number in the chain of hydraulic cylinders, while the highest speed of the piston movement is developed by the first hydraulic cylinder. The relative unevenness of the piston movement in comparison with the speed of the piston movement of the first hydraulic cylinder is determined by the differentiation of the hydraulic cylinder, while the hydraulic drive with the differentiation D = 2 has the greatest unevenness. It is shown that by the selection of the differentiation of the hydraulic cylinders, their stepwise arrangement and the displacement of the location of the bottom of the hydraulic cylinder, that it is possible to realize complex forms of the total trajectory of the points of attachment of the hydraulic cylinder rods. In the hydrostatic (power) hydraulic drive in the rod cavities of the hydraulic cylinders, depending on the serial number of the hydraulic cylinder, the thrust on its rod and the differentiation set different pressure levels, and the lowest pressure will be in the piston cavity of the last hydraulic cylinder. With uniformly loaded hydraulic cylinders, the pressure in the piston cavities depends only on the number of the hydraulic cylinder and its differentiation. In a hydraulic drive with hydraulic cylinders of equal power, the last hydraulic cylinder will develop the greatest force at the lowest piston speed. In addition, the work also shows that the reproducibility of the positions of unloaded rods of hydraulic cylinders of equal differentiation is not less than 1%. As a result of the experimental studies, a method was developed for the design of a volumetric hydraulic drive with sequential switching on of executive hydraulic cylinders, which can be used to solve the problems of hydrofication of mechanical engineering production (bending presses, sheet stamping), in shipbuilding (ship slipways), in flexible production systems, industrial and warehouse logistics.
Izvestiya MGTU MAMI. 2020;(4):65-75
pages 65-75 views

Results of field studies of a tractor of traction class 1,4 with an elastic damping mechanism in a power drive

Sen'kevich S.E., Il'chenko Y.N., Godzhayev Z.A., Duryagina V.V.

Abstract

The topic of this paper is analyzing the results of field studies of a tractor with an elastic damping mechanism in a power drive and its operational efficiency assessment in comparison with a serial tractor. The subject of the research is a tractor with an elastic damping mechanism in a power drive as part of a plowing unit with a mounted plow. The purpose of this work is a detailed analysis of the influence of the parameters of the elastic-damping mechanism on the performance of a tractor with a plow. Carrying out such studies makes it possible to obtain new experimental data on the operation of the elastic damping mechanism installed in the power drive of a tractor when aggregated with a plow. The control experiments were carried out in the same field during the summer and autumn periods of one year. The benchmark for comparative experiments was the same tractor, but with a blocked elastic damping mechanism (for brevity, it is called “serial”). The results were processed on a personal computer using a software package. To analyze energy efficiency, a conditional classification of sample variability based on the coefficient of variation was used. Spectral analysis was performed to study numerical slip data. The indicators of the energy assessment show that the unit with an elastic damping mechanism in the power drive of the tractor has better performance (travel speed, productivity and fuel consumption per hectare) than a similar unit with a more rigid transmission. The elastic damping mechanism creates more favorable conditions for the formation of the nature of the load of the nodes, with unsteady and steady-state modes of motion. Statistical analysis of numerical data on slipping showed that the use of the mechanism makes it possible to reduce the mathematical expectation of slipping. Analysis of spectral characteristics indicates that the elastic-damping mechanism absorbs frequencies, being a filter when aggregated with various tools. Everything mentioned above indicates a significant improvement in the characteristics of the unit when using an elastic damping mechanism.
Izvestiya MGTU MAMI. 2020;(4):76-87
pages 76-87 views

Investigation of the relationship between theoretical and actual turning radii of a tracked vehicle using mathematical modeling

Stadukhin A.A.

Abstract

Introduction. Determination of the traction force and power required in a turn by a tracked vehicle is based on analytical dependencies given in classical literary sources. In this case, the dependence of the theoretical and actual turning radius is usually not described accurately enough. Subject of study. A study of the dependence of the theoretical and actual turning radius and the influence of the parameters of the undercarriage of the tracked vehicle, the characteristics of the support base and the mode of movement on it was made. Methodology and methods. The study was carried out using a specially developed stationary rotation tracked vehicle (TV) model, which differs by taking into account the redistribution of normal reactions and implementation, allowing one to quickly carry out multifactorial experiments. The rotation of the TV in the model is described as a plane motion of a rigid body. In contrast to the classical approaches, the model allows one to study the rotation of the TV at a speed close to the critical drift. Results and scientific novelty. During computational experiments, the parameters of the chassis of the TV, the properties of the support base, as well as the speed of movement and the actual turning radius were varied. It was found that the classical dependences of the actual and theoretical turning radius need to be refined when driving at a speed close to the critical drift, while the form of the dependence is determined by the height of the center of mass of the TV. Practical significance. These features should be taken into account both when assessing the speed of the vehicle and determining the required thrust-to-weight ratio, and when working on the development of active safety systems for tracked vehicles.
Izvestiya MGTU MAMI. 2020;(4):88-100
pages 88-100 views

Optimization of the design and experimental study of the stress-strain state of the rear suspension balancer of an all-terrain vehicle

Shabolin M.L.

Abstract

Reducing the curb weight of wheeled vehicles has long been one of the priority areas of work of automotive engineers, since this can significantly improve the operational properties of a wheeled vehicle: improve dynamics, passability, reduce fuel consumption and emissions of harmful substances. A significant proportion of the vehicle's curb weight belongs to highly loaded parts of the frame, transmission and suspension. Therefore, the creation of lightweight, highly loaded parts will make a significant contribution to reducing the curb weight of the whole vehicle. The paper describes the application of the topological optimization method based on finite element modeling in the design of highly loaded parts of the chassis of vehicle. An example of the synthesis of the power circuit of the rear suspension balance bar of an all-terrain vehicle with a description of the design model, load modes and interpretation of the results is shown. The optimization problem was solved using a finite element model of varying density. Minimization of the potential energy of deformation was used as an objective function, and the target volume in fractions of the original design space was used as a limitation. A comparative analysis of the obtained design with analogous designs is presented. The formulation and results of an experimental study of the stress-strain state of the optimized balance bar are described. As a result of optimization, it was possible to achieve a reduction in the weight of the balance bar to 49% in comparison with an analogue design while maintaining the required strength. Experimental verification of the bearing capacity of the balance bar showed the need for more thorough verification calculations of optimized parts, including taking into account manufacturing and assembly errors.
Izvestiya MGTU MAMI. 2020;(4):101-104
pages 101-104 views

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