A mathematical model of the plane-parallel movement of an asymmetric machine-and-tractor aggregate

Technological peculiarities of cultivation and harvesting of some agricultural crops make it necessary to use asymmetric machine-and-tractor aggregates. However, for the time being there is no sufficiently complete, analytical study of the steady movement of such machine-and-tractor aggregates. This necessitates the development of a theory of stable movement of the aggregates which would allow choosing their optimal kinematic and design parameters. On the basis of the results of mathematical simulation, a system of linear differential equations of the second order is obtained describing transverse displacement of the center of masses of the aggregating wheeled tractor and turning of its longitudinal axis of symmetry by some angle around the indicated center of mass, as well as the deviation angle of the rear-trailed harvester from the longitudinal axis of the tractor at any arbitrary moment of time. This system of differential equations can be applied for numerical calculations on the PC, which will make it possible to evaluate the stability of the movement of the asymmetric machine-and-tractor aggregate when it performs the technological process

Theoretical study of the conditions of the maximum allowable slipping of wheel tractors

Received: October 1st, 2022 ; Accepted: March 15th, 2023 ; Published: March 17th, 2023 ; Correspondence: [email protected] process of tractor wheels slipping is accompanied by two forms of ground deformation: displacement and shearing. From the point of view of preserving the structure of the soil environment, wheel slip should be limited to displacement only. The limit of soil strength [σo] at this deformation can be a standardizing parameter. In this article an analytical dependence is developed, which allows using the parameter [σo] to establish the maximum permissible level of slipping of wheeled tractors. Of the soil parameters, the specified dependence includes the coefficient of sliding friction between the particles of soil medium and the coefficient of wheel rolling resistance on a particular agrotechnical background. Theoretical studies have established that the greater the value of this coefficient, the smaller should be the maximum permissible value of tractor slipping with a more economical effect on the soil environment. Compared to a tractor with a nominal drawbar pull of 14 kN, the use of a heavier tractor with a drawbar pull of 30 kN is possible with higher values of maximum permissible towing. This result is due to the magnitude of the vertical load on the wheel of the heavier tractor, which gives it a greater friction force between the tire wheel and the ground and allows the same contacting traction force to be realized at a lower level of slipping. The results of mathematical modeling using the developed analytical relationships indicate that with increasing the value of the angle of placement (slope) of the tractor wheel to the longitudinal axis of symmetry, the maximum permissible level of its slipping should be less. This will help to reduce the value of deformation (longitudinal shift) of the soil by the tractor during its working movement. When using the ground shear strength limit [σo] у as a limiting parameter for increasing the pitch and height of the tractor tire, as well as the width of the tractor wheel tyre, the maximum permissible level of its towing is more than 15%, which is an undesirable fact

Implementation of simultaneous performance of two technological operations with different machine-and-tractor units

Received: January 25th, 2022 ; Accepted: April 6th, 2022 ; Published: April 18th, 2022 ; Correspondence: [email protected] gap between two technological operations should be minimal in the production environment. For this, special combined (multi-operational) machine-and-tractor units (MTU) are used. Their agricultural machines have sequentially installed working devices for various technological purposes. In the absence of such MTUs, single-operation units are used. Such units more often have different working widths. For their simultaneous operation in the same field, the first unit (for example, a sowing unit) must have a wider width than the second one (for example, a rolling one). In practice, the opposite case occurs more often when the first unit's working width is less than the second unit's working width. As a result, the first machine-and-tractor unit delays the work of the second one. This article aims to develop the algorithm for the simultaneous operation of two machine-and-tractor units of different field performance. The first of them (a sowing unit) has a working width of 3.6 m, and the second (a rolling one) is 6.1 m. As a result, the following has been established using the example of processing a field of 80 hectares: the second unit should start its work (i.e., rolling the crops) when the first one (sowing) has sown a certain area. According to the formula proposed in the article, the size of this area is 44 hectares. Under natural working conditions, the second unit (rolling) started its work after the first (sowing) unit has sown 44 hectares of the field area. As a result, both units have completed the entire area with a half-hour gap, i.e., practically simultaneously and without delay from each other

Theoretical research into directional stability of trailed tandem- type disk harrow

Received: August 27th, 2021 ; Accepted: October 6th, 2021 ; Published: October 7th, 2021 ; Correspondence: [email protected] is one of the methods of soil cultivation, provides its effective crumbling, loosening, partial mixing and soil inversion. This ensures that crop residues on the soil surface are shredded and intermixing with loosened soil particles. Since, in addition to crop stubble, weeds are also counted as crop residues, soil disking, along with the use of herbicides, is often regarded as the most effective method of controlling the weediness of the agricultural background. Despite the fact that numerous studies on the disk harrow working process are available, insufficient attention has been paid to the study of the stability of harrow machine-tractor units, especially trailed ones. The purpose of this study is to establish the theoretical patterns that would provide for selecting the trailed disk harrow parameters that ensure the desired directional stability of the implement, which, in its turn, helps to achieve the desired qualitative performance of the disk harrowing machine-tractor unit. The principles of the theory agricultural machine, analytical mechanics, higher mathematics, as well as methods of PC-assisted numerical calculations have been used. According to the results of the study, it has been established that sufficient directional stability of the trailed disk harrow can be ensured if its working width B, the distance from the hitch point to the centre of resistance (parameter d) and the operating speed are properly selected. Determining the above-mentioned parameters of the disk harrow with the use of the obtained new analytical relations ensures achieving just their optimal combination, which provides for the maximum field productivity of the harrow machine-tractor unit with the satisfactory stability of disk harrow movement in the horizontal plane

Theoretical study to determine the standard size range of agricultural tractors

Since the tractor is the main energy source in agriculture, the state with highly developed agrarian production, tractor and agricultural machine building should have a fairly clear and consistent policy in the field of organizing the production and supply to agricultural producers of a wide range of tractors for various purposes. Such a policy is based on the type of mobile energy resources, i.e. tractors, based on a deep analysis and study of the volume of agricultural production, the needs for mechanized technologies, the theory of the operation of agricultural machines, the overall assessment of the development of high-tech agriculture. The purpose of this study is to develop theoretical bases for calculating the type of agricultural tractors based on an optimization of technical and economic analysis, taking into account the need for a qualitative and timely implementation of the entire closed set of works in agricultural production. During the research methods of machine use in agriculture, higher mathematics, economics, compilation of programs and numerical calculations on PC were used. The results of the study showed that the classification of tractors should be carried out not according to traction power (as is done in most countries of the world), but by the nominal traction force developed by them. It has been established that this gives a more accurate representation of the operational properties of an energy tool, which in turn allows for the very accurate and correct selection of complexes of appropriate agricultural machinery and implements for its effective operation. The presented theoretical approaches allow to determine with a high degree of accuracy the type of agricultural tractors for any country

Dynamics of Temperature Variation in Soil under Fallow Tillage at Different Depths

One of the important processes taking place during soil surface tillage is the variation of the soil temperature at different depths. The paper presents the results of research into the dynamics of soil temperature variation in terms of such parameters of the soil as its thermal diffusivity and temperature oscillation frequency. It has been established that the temperature oscillation amplitude decreases when the depth increases, following the logarithmic law. In this variation, the temperature difference between the 0–5 cm layer and the adjacent 5–10 cm layer has the greatest value. This circumstance is a favorable factor for the fallow tillage technology, where the soil is regularly cultivated to a depth of no more than 5 cm, in case of a moisture deficit. A decrease in the frequency of the soil temperature oscillations can result in the reduced level of its heating in different layers. In terms of qualitative changes, the reduction in soil thermal diffusivity results in the amplitude of the soil temperature oscillations being lowered and at the same time the maximum of these oscillations being shifted towards a delay

Motion stability estimation for modular traction vehicle-based combined unit

One of the promising ways of efficiently applying high power intensity tractors is their design and utilisation in the form of modular traction vehicles comprising two modules: the power module and the process module. In order to provide for the sufficient manoeuvrability of the modular traction vehicle, when its process module passes a turn, the latter is equipped with vertical and horizontal hinge joints. The freedom of the process module’s rotation with respect to the power module in the horizontal plane through the agency of the above-mentioned vertical hinge joint is restrained by a hydraulic cylinder, in which the chambers above and below the piston are connected via a throttle valve with a hydraulic resistance coefficient of about 1.03×106 N m s rad–1 . This paper is concerned with the theoretical and experimental research into the stability of motion (on turn spaces as well as in the transport mode) of a modular combined unit, when its velocity changes and/or the slip resistance coefficient of the tyres on the wheels of the process module, in which the hydraulic cylinder is equipped with a throttle valve with the above-mentioned hydraulic resistance coefficient, changes

Automated visual inspection algorithm for the reflection detection and removing in image sequences

Specular reflections are undesirable phenomena that can impair overall perception and subsequent image analysis. In this paper, we propose a modern solution to this problem, based on the latest achievements in this field. The proposed method includes three main steps: image enhancement, detection of specular reflections, and reconstruction of damaged areas. To enhance and equalize the brightness characteristics of the image, we use the alpha-rooting method with an adaptive choice of the optimal parameter alpha. To detect specular reflections, we apply morphological filtering in the HSV color space. At the final stage, there is a reconstruction of damaged areas using adversarial neural networks. This combination makes it possible to quickly and effectively detect and remove specular reflections, which is confirmed by a series of experiments given by the experimental section of this work

A mathematical model of the rear-trailed top harvester and an evaluation of its motion stability

Received: October 7th, 2021 ; Accepted: December 10th, 2021 ; Published: December 10th, 2021 ; Correspondence: [email protected] the quality of sugar beet harvesting to a great extent depends on the first operation in the process, which involves cutting and harvesting sugar beet tops. This technological process is performed with the use of either the haulm harvesting modules of beet harvesters or top harvesting machines as separate agricultural implements, which are aggregated with a tractor. At the same time, front-mounted harvesters are as widely used as trailed asymmetric implements, in which case the aggregating tractor moves on the already harvested area of the field. The purpose of this work is to determine the optimal design and kinematic parameters that would improve the stability in the performance of the technological process of harvesting sugar beet tops by means of developing the basic theory of the plane-parallel motion performed by the rear-trailed asymmetric top harvester. As a result of the analytical study, an equivalent scheme has been composed, on the basis of which a new computational mathematical model has been developed for the plane-parallel motion of the asymmetric top harvester in the horizontal plane on the assumption that the connection between the wheeled tractor and the rear-trailed top harvester is made in the form of a cylindrical hinge joint. Using the results of mathematical modelling, the system of linear second-order differential equations that determines the transverse movement of the centre of mass of the aggregating wheeled tractor and the rotation of its longitudinal symmetry axis by a certain angle about the said centre of mass as well as the angle of deviation of the rear-trailed asymmetric top harvester from the longitudinal symmetry axis of the tractor at an arbitrary instant of time has been obtained. The solving of the obtained system of differential equations provides for determining the stability and controllability of the motion performed by the asymmetric machine-tractor unit, when it performs the technological process of harvesting sugar beet tops