Machine-tractor Unit Research Articles

Determination of operation performance indicators of unit for mowing crops with the simultaneous incorporation of their stubble into the soil

When harvesting grain crops and forage grasses using a two-phase method, trailed and/or mounted windrowers are usually used. After their passage, stubble remains on the field, which intensively loses soil moisture under sunlight and wind. To reduce these losses, the stubble, along with the soil, is crushed using disc harrows. Due to the use of two sequentially operating units (harvesting and soil-cultivating), their total operating time increases. This does little to preserve soil moisture in the cultivated field. This article provides an example of a more effective solution to this problem. It consists of using one machine-tractor unit instead of two. The proposed combined unit mows an agricultural crop in one working pass and ensures stubble crushing and incorporation into the top layer of soil. The unit consists of a wheeled tractor with a front hitch linkage, a front windrower and a disc harrow mounted behind the tractor. It has been established that the laboriousness of compiling such a unit, considering the tractor's transformation to reverse, is insignificant and amounts to 1442 person-hours. The use of the new unit assists in reducing soil moisture losses. Over a month, it can reach 4.1–5.2% in absolute terms and 15–45% in relative ones. The combined unit movement velocity should be close to 2.5 m s−1 to ensure such a reduction in soil moisture losses. Combining two technological operations performed by one machine-tractor unit does not impair its reliability. At the same time, there is a reduction in processing time for one field by almost half and a decrease in fuel consumption per unit of performed area by 2.25 times.

SUBSTANTIATION OF CHANGES IN THE CERTIFICATION OF THE TRACTOR DRIVER’S WORKPLACE IN MODERN MACHINE-TRACTOR UNITS

The study aims to identify possible changes in the working conditions of tractor drivers under the computerisation of workplaces and to develop proposals for changing the requirements for sanitary standards in the design of tractors and agricultural machinery. The article analyses the impact of modern technologies on the working conditions of tractor drivers in agriculture. It investigates various aspects of work, including using on-board computers, air conditioning, and satellite navigation, and their impact on workers’ health. The authors consider health risks, such as increased noise levels and work with on-board computers, and reveal the lack of consideration of these aspects in regulatory documents. In particular, we have found that using on-board computers significantly simplifies the process of controlling agricultural machinery but can lead to increased noise and vibration levels, negatively affecting workers’ health. Some studies have shown that prolonged work with on-board computers can lead to the development of occupational diseases, such as musculoskeletal disorders, impaired vision, and others. In addition, air conditioning in tractor cabs can cause colds due to sudden temperature changes and increase the risk of legionella infection due to the water condensation accumulation in ventilation systems. The research also found that the legal and regulatory documents governing the working conditions of tractor drivers do not consider the use of modern technologies, which creates gaps in worker protection. Regulatory documents should contain requirements for the parameters of monitors and their placement in the working area of tractor drivers in agricultural production, such as adjusting the reflectivity of the screen, the main adjusted visual characteristics of monitors, and the location of video terminals in the tractor cab without being directly in the line of sight. It is necessary to develop measures to prevent the overwork of tractor drivers. Regulations should include rules for the use of air conditioners, as well as for cleaning air conditioning ducts and replacing filters on time. The general conclusion is that there is a need to strengthen the regulation of tractor drivers’ working conditions and to include requirements for using modern technologies in the relevant regulations. These measures will ensure the safety and health of workers in agriculture and reduce the risk of occupational diseases. Keywords: machine-tractor unit, tractor driver, workplace certification, labour protection, video terminal.

К ФОРМИРОВАНИЮ МОДЕЛИ ЭФФЕКТИВНОСТИ ФУНКЦИО-НИРОВАНИЯ СЕЛЬСКОХОЗЯЙСТВЕННОГО ТРАКТОРА В СОСТАВЕ МТА ПРИ РАБОТЕ НА АЛЬТЕРНАТИВНЫХ ВИДАХ ТОПЛИВА

The development of the Russian agro-industrial complex provides for increasing the efficiency of the functioning of energy machines while simultaneously reducing energy and labor costs. A promising direction for saving diesel fuel and improving the environmental performance of mobile agricultural machinery is the use of alternative motor fuel. In modern agricultural machines, this will be reflected, first of all, in the parameters of the working process and its flow in the engine, as well as in the indicators of power, fuel efficiency and environmental friendliness of its operation, which, to one degree or another, will lead to changes in the indicators characterizing the operational properties of a machine-tractor unit. The functioning of the engine as a model can be presented in the form of a multi-level and multidimensional system in which the control flows will be indicators of the work process (effective power, indicator pressure, the amount of fresh charge entering the cylinders, etc.), fuel supply parameters (cyclic supply, fuel injection pressure, fuel temperature, etc.), which depend on the physicochemical and operational properties of the alternative fuel. The proposed model provides for the determination of the rational composition of the fuel, technical solutions for adapting the fuel system for the effective supply of alternative fuel to the engine cylinders with the required indicators, as well as determining their influence on the parameters of the operational efficiency of the tractor as part of machine-tractor unit. The obtained numerical values of the parameters of the diesel operating process and fuel supply, depending on the physical-chemical properties of the alternative fuel used, make it possible to determine the performance indicators of the tractor as part of machine-tractor unit and evaluate the efficiency of its operation on various alternative types of fuels, in comparison with using petroleum diesel fuel.

Determining conditions for providing maximum traction efficiency of tractor as part of a soil tillage unit

This study aims to investigate the operation of a tractor as part of the tillage unit on the basis of analysis of its interaction with the supporting surface and the correlation between the mass of the tractor and tool. The classic approach to determining the efficiency factor does not take into account the extensive system of power take-off shafts and the extent of their use in combined tillage units. To solve the related problem, a mathematical apparatus was built in the study, which makes it possible to determine the rational ratio between the traction force of a tractor and the mass of the tillage unit. Underlying the methodological basis of the work is the generalization and analysis of the study of traction indicators of the tractor as part of the tillage unit. Empirical models of unit operation were constructed by employing the basic principles of the system approach and analysis of technical systems. When improving the methodology of research using the method of partial accelerations and our devised procedures, it was possible to significantly reduce the time without compromising the quality of results. The maximum traction efficiency for John Deere 8R series tractors as part of the tillage unit was determined, ηTmax=0.719, as well as the conditions for its provision. The traction efficiency for tractors with wheel formula 4K2, mass Gim=6–10 t, with power consumption from 60 % to 80 % was determined; it is 0.58–0.64. The results of the study make it possible to obtain a new solution to the scientific problem of ensuring the maximum traction efficiency of the tractor as part of the tillage unit, based on the rational ratio between the traction force of the tractor and the weight of the machine-tractor unit. The proposed system approach could be used to justify the layout of units and recommendations regarding their modes of operation in the case of instability of operating mass and traction force

Performance evaluation of the universal steerage hoe design using the Harrington’s desirability function

Choice of the most effective hoe design among their set, used in practice, has been justified. Methodology has been developed for selecting the most effective hoe design for complete tillage from those offered by LLC Trading House MTZ-NORTH-WEST. For each model, the required engine power, price and weight of machine are justified, per 1 m of working width, as well as energy intensity of the cultivation process per 1 hectare of cultivated arable land. Fulfillment of the initial requirements for full cultivation has been analyzed in comparison with series-produced, widely used test units, and preference has been given to the proposed ones, due to the complexity of machine-tractor unit (MTU). Proposed decision-making technique for choosing the best design of a universal steerage hoe, is based on the Harrington’s desirability function. Scales have been developed for the desirability of justified private evaluation indicators of the design of compared hoes, which have been taken as: tractor specific power, required for hoe aggregation, price and weight of structure, as well as the work process energy intensity. For each of the five hoes, a composite index of comprehensive design assessment has been found. Preference is given to the hoe with maximum value of composite index of comprehensive design assessment. Calculations have accounted for the value of the composite index, both considering weight of private evaluation indicators and without it. According to calculated data, preference from the family of universal steerage hoes has been given to the METI ULTIMA 15000 wide-grip designs due to its optimal power-to-weight ratio and its unit price, even despite the highest work process energy intensity.

Methodological foundations of directional stability of a machine-tractor unit in sloping agriculture

The article describes a method for holding a tractor unit (MTA) on a slope when performing technological operations by changing the angles of the tractor wheels and the mounted machine. The variants of the MTA movement trajectories are considered, graphs of wheel deflection angles are presented, and an algorithm for calculating compensation for the total displacement of the MTA with excessive turning on the slope is presented. Calculations have shown an 11% reduction in the reaction time of the unit to changes in landscape characteristics with operational adjustment of the angle of withdrawal of the “equivalent” wheel, carried out by varying the pressure exclusively by the support and transport wheels of the mounted gun.

ОБОСНОВАНИЕ РЕЖИМОВ РАБОТЫ ТРАКТОРА К-735 С ПОЧВООБРАБАТЫВАЮЩЕ-ПОСЕВНЫМ КОМПЛЕКСОМ КУЗБАСС ПК 6.1

Modern crop production is characterized by the introduction of resource-saving methods of processing and cultivation of crops aimed at preserving and increasing soil fertility. The purpose of the research is to determine traction and energy indicators and substantiate the operating modes of a machine-tractor unit based on a K-735 wheeled tractor with a Kuzbass PK 6.1 sowing complex. Based on research, it was found that the pulling force in sowing varies from 19.0 kN to 37.43 kN, the output hook power ranges from 40.11 to 124.26 kW and depends on the speed of the unit, the depth of sowing and the weight of the bunkers. The modes of operation of the unit are justified: at a depth of 5 cm in the second mode, 3 gears at a speed of rotation of the diesel crankshaft 1900 min–1 , after unloading the seeds 50 % transition to the 4th gear of the second mode at a speed of rotation of the diesel crankshaft in the range from 1730 to 1750 min–1 ; at depths of 7 and 9 cm on the second in the 3rd gear mode at a speed of rotation of the diesel crankshaft 1900 min-1 , after unloading the seeds 75 % transition to the 4th gear of the second mode at a speed of rotation of the diesel crankshaft in the range from 1730 to 1750 min–1 .

Experimental determination of the parameters of the adaptive support of the power unit of the machine-tractor unit

The research aim is to experimentally determine the parameters of the adaptive support of the power unit of the machine-tractor unit. The need to use adaptive supports for power plants of machine-tractor units is due to a change in their speed and load modes of operation in a wide range. The currently used supports have constant parameters, which are determined, as a rule, by statistical characteristics and characteristics of the nominal operating mode. Reducing the negative impact of vibration on the efficient performance of the power plant is proposed by creating supports with adjustable characteristics. Changes in the damping parameters of the used supports, depending on the modes of its operation, will reduce the vibration amplitudes of the power plant in the entire range of its operation, which will improve its performance indicators. The stiffness and damping coefficient were chosen as the determined parameters of the support. For this, experimental transition functions are fixed on a non-motorized stand, and they are approximated by solutions of differential equations of the first, second and third orders. The previously obtained curves are smoothed. The order of the differential equations depends on the type of transition functions and are selected according to numerical criteria. The adequacy of the obtained values is checked by comparing the experimental and theoretical curves. The scientific novelty lies in the methodological and technical diagnostics based on differential equations that was considered for agricultural units for the first time. The proposed methodology is of interest to engineers and technicians involved in the design of efficient supports for power plants of machine-tractor units.

РЕЗУЛЬТАТЫ ИССЛЕДОВАНИЙ ПО ОПРЕДЕЛЕНИЮ РАЦИОНАЛЬНОГО СПОСОБА УДАЛЕНИЯ ЗАГРЯЗНЕНИЙ ИЗ МОТОРНОГО МАСЛА БЕЗ ЕГО СЛИВА ИЗ СИСТЕМЫ СМАЗКИ

Contaminants are formed in diesel internal combustion engines of tractors during operation under the influence of high temperatures and loads on the parts of the cylinder-piston group, which then enter the engine oil, which affects the service life of the oil and the characteristics of the machine-tractor unit. An important measure that affects the contamination of parts and the service life of the oil is flushing the lubrication system during routine replacement of used oil. However, for a number of well-known objective and subjective reasons, this technological method is practically not carried out under real operating conditions. Resource-saving technology for flushing the lubrication system with motor oil running in the tractor engine was developed at TSTU. A number of technological methods for cleaning oil from contaminants and resins under the influence of chemical reagents added to the oil, followed by idling the engine, have been developed. The dependences of changes in contamination, base number, viscosity and color of the oil on the cleaning method, the concentration of the addition of urea, monoethanolamine, and isopropanol reagents were obtained. It has been determined that the addition of isopropanol can increase the flash point of the oil. The dependences of the change in base number and viscosity on the concentration of monoethanolamine with isopropanol in the oil have been established. The rational concentration for adding this additive is 2–3% of the oil volume. It was determined that the color of the oil changes from 9 to 4 points per unit. CNT. Research on the use of finely dispersed contaminants as a separating agent and coagulant has established that 3% vol. carbamide dissolved in ammonium hydroxide allows you to get the best result. Research in this area will be continued and requires confirmation in a wide range of oils and the technological state of tractor engines.

Dependence of Tractor Traction Properties on Agricultural Machinery Connections

Tractor traction properties depend on many factors including engine power, operating weight and tractor weight distribution across axles, dimensions, profile, gears range and gear count in the gearbox. Moreover, the tractor technical condition plays a vital role, encompassing aspects from the fuel system affecting the engine power output, to the chassis, influencing terrain traversability, maneuverability, and soil deformation. (Research purpose) The paper addresses several research problems. To investigate the impact of the agricultural machinery connections with the tractor on the tractor traction properties, and determine the impact of agricultural machinery weight, and grip width on the main technical and economic parameters. To analyze how geometrical parameters of tractors and agricultural machinery correlate with soil reactions under the machine support wheels as well as the front and rear wheels of the tractor. To determine the influence of the design characteristics of cultivators with varying working widths on the main operational properties of the machine-tractor unit. (Materials and methods) The study involves examining the operation of the Belarus 82.1 tractor with cultivators KPS-4 and KPS-5 from different manufacturers. Various methods were employed, including calculation, calculation-construction, calculation-graphic analysis, economic-mathematical techniques, along with comparison, measurement, and description. (Results and discussion) This study identified indicators impacting the load redistribution transmitted to the tractor from mounted cultivators. Based on these indicators, alterations in soil reactions under cultivator support wheels and the tractor’s rear wheels were deduced. (Conclusions) The calculations on the effect of mounted cultivators with different working widths (different operating weight) on the redistribution of soil reactions between axles, enabled the determination of modifications in tractor traction force, machine-tractor unit productivity, and specific fuel consumption.

Assessment of tractor track width compatibility with crop inter-row spacing

Various factors can exert detrimental effects on crop growth and development, among which the influence of the machinery's running gear within the machine-tractor unit stands out, particularly within the soil vicinity encompassing the plant's root system. As a result, the area of soil compaction arising from tractor wheel pressure increasingly covers the plant's protective zone. This poses challenges for both root system growth and development, as well as the optimal uptake of soil nutrients, often leads to plant damage or even trampling. Presently, there is no universally accepted metric for assessing the compatibility between tractor track width and the specific inter-row spacing under cultivation. (Research purpose) Development of an indicator to assess the compatibility of the tractor track width with the cultivated inter-row spacing. (Materials and methods) The analysis demonstrates that the level of compatibility of the tractor track to the crop inter-row spacing is determined based on the dimensions of the crop spacing, the tractor track width, the protective zone outlined by agrotechnical standards, the deviation of the wheel trajectory from the axis of row symmetry, and tire size. (Results and discussion) An analytical correlation has been derived to determine the level of compatibility between tractor track width and crop inter-row spacing, using the context of cotton cultivation as an illustrative example. It has been revealed that among the serial tractors utilized within cotton farms across the region, full-fledged operational performance is exclusively achieved when row spacings measure 60 and 90 centimeters. In contrast, the utilization of this machinery on row spacings of 70 and 76 centimeters leads to detrimental outcomes such as row trampling and plant damage. (Conclusions) The viability of the developed indicator has been determined and validated. The improvement of the tractor propulsion system should be aimed at devising a technical solution that facilitates seamless adjustment of track width over a broad spectrum, thus allowing for adaptability to diverse row spacing requirements.

Influence of the harvesting method on the processes of moisture accumulation and yield capacity

BACKGROUND: A feature of the climate of the steppe zones of Western Siberia is the frequent recurrence of droughts. Accumulation and preservation of solid precipitation in the form of snow on field in winter is a relevant task, since this directly affects the accumulation of productive moisture in soil by the time of sowing and, as a result, the formation of the future harvest.
 AIMS: To determine the influence of the snow cover level, moisture reserves and productive moisture in the soil on a stubble background, harvested with a thresher for direct combining and a rippler on the yield capacity of spring wheat.
 METHODS: The field experiment was carried out in 2021-2022 in the steppe zone of the Omsk region at the Novouralskoye Scientific and Production Enterprise of the Omsk Agrarian Scientific Center. In the autumn of 2021, sections of the field were marked out for measurements: wheat stubble field after the thresher for direct combining, wheat stubble field after the rippler. In March 2022, indicators of the height of the snow cover and moisture reserves in the snow were determined on the marked areas using the VS-43 balance snow gauge. In the spring, wheat was sown with the machine-tractor unit, consisting of the RSM 2400 tractor and the Amazone Condor 15001-C sowing facility. In autumn, the chosen field sections were harvested with the Sampo-250 seed-production harvester.
 RESULTS: It was found that after harvesting with the thresher for direct combining with a stubble background of about 15 cm, there is a decrease in the moisture reserve in the one-meter-depth layer by almost 2 times, down to 48.6 mm, by the spring period. The moisture reserve on a high stubble background, after the operation of the rippler, on the contrary, was able to persist, as there were 96.6 mm of productive moisture in the one-meter-depth layer by the time of sowing. The average grain yield on the field section sown after the rippler was 1.16 t/ha. The average grain yield on the field section sown after harvesting with the thresher for direct combining was 1.06 t/ha. Thus, the grain increase was 0.1 t/ha or 9.4%.
 CONCLUSIONS: The carried out field experiment indicates that, when harvesting with a rippler, there is a twofold increase in productive moisture by the time of sowing, while the increase in the yield of spring soft wheat grain was 9.4%.

РЕЗУЛЬТАТЫ ЭКСПЕРИМЕНТАЛЬНЫХ ИССЛЕДОВАНИЙ ПЛУГА-РЫХЛИТЕЛЯ В АГРЕГАТЕ С ТРАКТОРОМ ТЯГОВОГО КЛАССА 5

The results of experimental studies of the machine-tractor unit (MTA), consisting of a tractor of traction class 5 K-744R and a mounted plow-ripper PBS-16 presented in the article. Determining the performance of the plow-ripper in the experiments was provided by changing the translational speed of the machine-tractor unit. Fuel consumption was recorded from the moment the unit entered the test plot at a steady speed and the unit left it. Experimental studies of the work of the MTA were carried out in the field conditions of the Marxovsky district of the Saratov region. Agrotechnical indicators were determined during the processing of fields on the stubble of chickpeas and millet. It has been established that the plow-ripper can be aggregated with tractors of traction class 5. The rational mode of operation of the plow with a working width of 6 m is ensured at a speed of 7.2-9.0 km/h and a working depth of 35 and 25 cm. unit operation was 3.6-4.5 ha/h, fuel consumption was 12.9-11.7 kg/ha. The unit provides a high degree of soil crumbling with a moisture content of 17-20% with the safety of stubble and plant residues on the agrobackground of millet up to 78%, on the agrobackground of chickpea up to 42%. Loosening the arable horizon up to 35 cm with mulching of the surface layer creates optimal conditions for the accumulation of moisture in the autumn-winter period. The movement of the MTA in the corral by the shuttle method, without the formation of dump and breakup furrows, provides a flat, ridgeless surface of arable land.

MODELING OF THE FLOW ADAPTIVE SYSTEM FOR CONTROLLING THE SOIL TILLAGE

It is well known that one of the significant disadvantages of the development of modern technological processes is the use of aspects of thinking associated with the use of already used design positions. From a practical point of view, there is no single optimal solution for tillage in agriculture. The methodology for solving complex, multipolar problems of quality and efficiency of technology must take into account a significant number of factors and be presented in an accessible form for the response of the working bodies of tillage machines. Precision tillage has great potential. The result of tillage operations can be improved depending on the optimal solution of construction working bodies and technological parameters of cultivating, which, in addition, can be adapted to the tillage technology depending on the local agro-climatic conditions. The article presents the results of the synthesis of the system of adaptive control of soil cultivation by creating a complex technological system with modeling of the structural-matrix schemes and on-stream technological influences of working bodies of machines and external agro-climatic conditions on the agrophysical state of the soil. The research methods are methods of analysis of structural schemes of technological process control systems; system-analog modeling of tillage control systems; structural analysis and synthesis of technological changes in agrophysical indicators of soil tillage. The main results are the structural diagram of the on-stream adaptive control system of the tillage unit for the requirements of precise agriculture; matrix diagram of the imaging and generalized system of equations of on-stream adaptive control of working bodies of tillage machines; system-analog model of the machine-tractor unit with the adaptive control system of working bodies.

РОЗРОБКА НОВОЇ МЕТОДИКИ ЕКСПЕРИМЕНТАЛЬНИХ ДОСЛІДЖЕНЬ ІНТЕНСИВНОСТІ КОЛИВАЛЬНИХ ПРОЦЕСІВ МАШИННО-ТРАКТОРНИХ АГРЕГАТІВ

An important operational indicator of agricultural machine-tractor units is the smoothness of movement, which significantly affects the traction and dynamic performance of their work, productivity, agronomic qualities of the operation, traffic safety, durability and efficiency. As a rule, it is evaluated by the influence of oscillations (translational vertical, transverse, angular longitudinal, etc.), on these indicators, as well as on the physical condition and health of operators who control these units in real production conditions. This article presents an improved method and results of experimental assessment of the smoothness of the movement of the modular agricultural unit, which moves in the footsteps of a constant technological track. Studies of the smoothness of the modular unit showed that the graphs of normalized correlation functions of vertical oscillations of the modular agricultural tool developed by us in its motion in the wake of a constant techno-logical track is characterized by a function containing along with random components harmonic, which are expressed by attenuating periodic oscillations. The range of frequencies of oscillations of the frame of the agricultural tool is concentrated in the range from 0 tо 20 s−1, which is consistent with the frequency range 0…0.3 s−1 in which the variances of oscillations of inequalities of a profile of traces of a technological track are concentrated. Studies have confirmed the effectiveness of the method of estimating the intensity of vertical oscillations of the agricultural unit measuring and recording system based on a tablet computer with Android operating system with built-in accelerometer sensors and Accelerometer Meter application. The developed technique of mathematical modelling and experimental determination of vertical oscillations of the machine-tractor unit can be used in the study of the dynamics of other agricultural machines and units.

High-clearance front driving axle to the cotton-growing tractor

The results of research and development and experimental-design activities on creating the front driving axle with an increased agrotechnical clearance for perspective universal cotton cultivating tractor 4K4 are specified in the article. The application of the 4K4 propulsion scheme in the design of a cotton-growing row-crop tractor will ensure aggregation of the main set of machines of the cotton complex with a working width of four or more rows due to increased tractor traction capabilities by 15-18%. At the same time, a decrease in the vertical load on each individual wheel, characteristic of 4K4 tractors, provides better directional stability in the Machine Tractor Unit and safe lateral static stability, and also creates the opportunity for year-round use of the tractor in transportation and field work as well.

Forecast for the Adaptive Tillage System

Precision tillage has great potential. The result of tillage operations can be improved depending on the optimal solution of construction working bodies and technological parameters of cultivating, which, in addition, can be adapted to the tillage technology depending on the local agro-climatic conditions. The article presents the results of the synthesis of the system of adaptive control of soil cultivation by creating a complex technological system with modeling of the structural-matrix schemes and on-stream technological influences of working bodies of machines and external agro-climatic conditions on the agrophysical state of the soil. The research methods are matrix methods of analysis of structural schemes of technological process control systems; system-analog modeling of tillage control systems; structural analysis and synthesis of technological changes in agrophysical indicators of soil tillage. The main results are the structural diagram of the on-stream adaptive control system of the tillage unit for the requirements of precise agriculture; matrix diagram of the imaging and generalized system of equations of on-stream adaptive control of working bodies of tillage machines; system-analog model of the machine-tractor unit with the adaptive control system of working bodies.

Selection of the analytical dependency for assessment of slipping of the Kirovets K-7 wheeled agricultural tractor

BACKGROUND: The accuracy of prediction of towing properties is related to selection of the analytical dependency for assessment of slipping in the process of development or modernization of agricultural tractor in order to define the correct configuration of a machine-tractor unit. The relevance of the study lies in justification of the dependency describing slipping of wheels of modern high-powered 4K4b tractors and needed for study of tractors towing properties. AIMS: Justification of the analytical formula of slipping for better accuracy of towing properties prediction at development stages and modernization of 4K4b tractors and units conjugated to them. METHODS: Known analytical dependencies of slipping were analyzed in the study in order to compare the theoretical assessment results with the results of field-testing at harvest field carried out at machine testing stations according to common method. The theoretical and experimental results were obtained for the Kirovets K-7 series agricultural wheeled tractors. The experimental data of the Kirovets K-7 series tractors was approximated in order to find new dependencies for analytical determination of slipping at harvest field. The approximation coefficient was taken as the criterion for assessment of accuracy of experimental data description by the dependencies. RESULTS: Among the considered analytical dependencies for prediction of slipping coefficient value, the equations which describe the experimental data of towing testing of the Kirovets K-7 series tractors the most satisfactorily were outlined. Based on approximated experimental data, the equations of slipping depending on specific towing force were obtained. There is the equation common for all tested tractors and there are separate equations for tractors with 32-inch and 38-inch tires. These equations provide with the best approximation of description of tractors. Values of specific towing force correlating to maximal towing efficiency and acceptable slipping coefficient of 16% for the Kirovets K-7 series tractors were obtained. CONCLUSIONS: Some existing and new proposed in the article equations can be used for prediction of values of slipping coefficient at creating of potential towing characteristic for high-powered 4K4b tractors.

The properties of machine-tractor unit (MTU) regarding soil preparation with bed ridging

BACKGROUND:One of the main criteria for assessment of work performance is productivity. It depends on a number of indicators: towing resistance, optimal use of energy, used technical equipment, the adaptability of the equipment to the operation conditions, etc. Experimental studies are required in order to establish the patterns of influence of these indicators on work efficiency.
 AIMS:Carrying out theoretical calculations and practical observations on the process of bed ridging for potatoes, assessment of the unit assembly for the technological process performing and the using of the unit.
 METHODS:Field tests of a machine-tractor unit with subsequent result processing using the Microsoft Office applications.
 RESULTS:Recommendations are given for practical use in the unit formation depending on velocity and operation width of the unit for various values of specific resistance.
 CONCLUSIONS:The practical value of the study lies in the opportunity of using the proposed patterns for optimization the machine-tractor unit assembly according to operation conditions, selection of power unit, development of combined machines and units.

Теоретичне дослідження стійкості руху асиметричного посівного машинно-тракторного агрегату

Goal. Theoretical evaluation of the effect of asymmetric connection of the row drill to the tractor on the stability of the movement of the sowing unit in the horizontal plane. Methods. Theoretical studies were carried out using the methods of theoretical mechanics, higher mathematics and the theory of automatic control of dynamic systems. Numerical calculations and construction of graphical dependencies were performed on a PC using the Mathcad 15.0 programming environment. Results. Practically all existing machine-tractor units for sowing row crops (corn, sunflower, soybean, etc.) are symmetrical. This is because each row seeder has an even number of sowing sections, and the ratio of the size of the tractor track to the row width of the row crop is an even integer (k). This article presents the results of research on the sowing unit, in which, with an even number of sowing sections of the seeder, the number k is equal to 3, which is odd. As a result, an asymmetric unit was obtained, in which the seeder is offset in the transverse direction from the axis of symmetry of the tractor by half the width of the row spacing, which is equal to 70 cm. In practice, such displacement of the seeder is carried out by hanging it on the tractor with the help of a specially designed transition device. Conclusions. With the use of mathematical modeling of the movement of the seeding machine-tractor unit in the horizontal plane, it is shown that the right-side transverse displacement of the planter by 0.35 m forms a constantly acting turning moment. But it has less effect on the stability of the movement of the sowing unit than the similar moment created by the marker. Calculations have established that increasing the input resistance coefficients of the tires of the tractor wheels, which can be achieved by correspondingly increasing the air pressure in them, leads to a desired decrease in the amplitude-frequency characteristics of the seeding unit’s development of the turning disturbance moment. Such a solution is more effective concerning the tires of the tractor’s rear wheels.