BACKGROUND: The performance of grain cleaning machines (GCM) of the air-sieve type and the quality of grain cleaning depend on the uniformity of the loading of the sieves, which is determined by the design of the supply-distribution device. A decrease in the inclination angle of the feeding device surface leads to a decrease in the intensity of supply of the heap closer to the axis, further reduction leads the heap to stop in this area. Therefore, the inclination angle reduction for the feeding device is below the friction coefficient that leads to a decrease in the loading distribution uniformity.

AIMS: Determination the dependence of the sorting process parameter of a heap of sunflower seeds on the material for the feeding device surface in the MVU-1500 air-sieve GCM.

METHODS: To determine the inclination angle of the feeding device in the process of sorting the Lakomka variety sunflower seeds, which affects the parameters of the pneumatic system of the MVU-1500 air-sieve GCM, an experimental installation was built to determine the heap movement velocity. The used methods were a privately developed methodology, methods of mathematical statistics and laws of theoretical mechanics.

RESULTS: The movement velocity of the heap of sunflower seeds on the surface of the feeding device were considered. Using the feeding device, the experimental and theoretical movement velocities of the heap of sunflower seeds on its surface made of metal and fluoropolymer included in the standard and improved MVU-1500 air-sieve GCMs were determined.

CONCLUSIONS: The practical value of the study lies in determining the theoretical movement velocity of the heap of sunflower seeds on the GCM’s feeding device surface which depends on its inclination angle as well as on the optimal material for it.

BACKGROUND: Handling and safety requirements to high-speed tracked vehicles (HSTV) rise in tandem with the growth of average motion velocities. The issue of ensuring continuously variable turn radius at curvilinear motion is relevant for HSTVs. Current layouts of steering mechanisms are able to meet this requirement, however they have certain disadvantages and are not compatible with electronic systems improving motion safety and lowering demands to mechanic-drivers’ skills.

AIMS: The synthesis of control laws for dual-flow transmission with a hydrostatic steering mechanism (HSSM) controlled by an electromechanical actuator which exclude “hard” links between steering handwheel and working volume adjustment mechanism of the HSSM.

METHODS: The study methods are based on using numerical simulation and ensuring real-time operation of the developed models. In addition, the study methods include synthesis of control algorithms for vehicle’s mechanical systems, used in on-board controllers, with adequacy assessment at virtual and laboratory experiments.

RESULTS: The method of development of control systems (CS) making possible to develop and to debug CSs without a HSTV prototype has been put into force. With using the described method, the total time of CS development and debugging reduces. Workability of the method is proved with the example of development of the CS for curvilinear motion of the HSTV with dual-flow transmission.

CONCLUSIONS: The study aim has been achieved, the accomplished work shows validity of the given methof of CS development.

The vehicle cross-country power depends both on the mover type and its weight-and-dimensional parameters, and on the physico-mechanical soil properties. Research of the interaction between the mover and a deformable soil at the stage of research and development using mathematic simulation makes it possible predicting the vehicle cross-country power.

The main mechanical soil parameters are the angle of internal friction and cohesion, which affect the process of interaction of the wheel with the deformable soil, since both normal and shear forces in the contact area. In this paper, sandy soil mathematical model is proposed and verified, and its parameters are determined for further research.

The developed mathematical model of the interaction of the wheel mover with a deformable soil is based on the application of the method of discrete elements. In this paper, the wheel mover force factors when moving on cohesionless soil are analyzed and also forms the dependence of the specific traction force on the specific circumferential force for various wheel rolling modes was obtained. As a result of applying the method of discrete elements to study the interaction of a wheel mover with a deformable support base, it is possible to determine the traction characteristic. Thus, the application of this method will reduce the number and scale of field tests.

Using the developed mathematical model the planetary wheeled mover traction characteristic was obtained and the comparative analysis with the nature test results was carried out.

On April 7, 2023, our colleague, Doctor of Technical Sciences, Professor, Honorary Worker of Higher Professional Education, Deputy General Director for Science of the Central Research Automobile and Automotive Institute (NAMI), a member of the editorial boards of the “Tractors and Agricultural Machines” and “Izvestiya “MAMI”” journals Sergey V. Bakhmutov passed away.

Sergey V. Bakhmutov was a prominent specialist in the following scientific fields: vehicle dynamics, active safety, optimization of design parameters, highly automated transport and technological facilities.

He was the author and co-author of about 170 scientific papers, including 20 books, 22 certificates of authorship and patents for inventions and utility models.

BACKGROUND: Automotive engines are one of the environment pollutants with harmful substances and greenhouse gases. Recently, the field of carbon-free or carbon-neutral energy has become the most relevant. In this regard, the task of reducing the carbon footprint of automotive equipment equipped with internal combustion engines remains urgent. This can be done by complete or partial replacement of the fuel with the carbon-neutral one, such as plant-origin biofuels.

AIMS: Study of low-temperature properties of fuel blends based on biodiesel derived from frying oil wastes.

MATERIALS AND METHODS: The vegetable oil ether was derived from purified frying oil wastes by esterification. Then fuel blends were obtained by mixing the derived ether with diesel fuel of different brands and butanol. The study of viscosity-temperature properties and density of the obtained fuel blends was carried out in the temperature range from -20°C to 40°C. The methods and equipment for determining these parameters meet the requirements of GOST.

RESULTS: The obtained study results helped to conclude that blended biodiesel in certain proportions can be used as fuel even at negative ambient temperatures, which is not uncommon for the start of a sowing campaign in spring and the end of field work in autumn in sharply continental climatic conditions.

CONCLUSIONS: The practical value of the study lies in the possibility of using fuel blends based on biodiesel derived from frying oil wastes at low temperatures.

BACKGROUND: Soil-cultivating machinery and tools equipped with rotary working bodies are effectively used at operations of surface tillage. However, the subject of furrow formation with rotary working bodies is unaddressed to the full extent that makes it a relevant issue for the study.

AIMS: Revealing the patterns of furrow formation with rotary working bodies equipped with the cutting blades made along the elliptical line at the angle to the working body rotation plane.

METHODS: The grapho-analytical method is presented in the article and used for defining the parameters of a furrow formed with the following types of rotary working bodies: a spherical disk with a closed surface, an annular working body and a rotary working body with the cutting blades made along the elliptical line and set up at the acute angle to the rotation axis. The experiments were carried out in controlled laboratory conditions with a physical model of the rotary working body with the cutting blades made along the elliptical line in a soil channel filled with dampened sand. During the experiments, the attack angle was 20-40° with a step of 10° and the kinematic coefficient, which is the ratio of circumferential velocity to transverse velocity, had the following values: 1, 1.4, 1.8 and 2.2.

RESULTS: The cutting blades made along the elliptical line form short furrows with the ellipse-shaped cross-section and with the angle of inclination from the movement direction of 20-40° depending on the attack angle and the kinematic coefficient. Meanwhile, the furrows formed with the working body have the form of a parallelogram at the top view.

CONCLUSIONS: The practical value of the study lies in revealing the features of furrow formation with rotary working bodies equipped with the cutting blades made along the elliptical line aimed to making a flat bottom of a furrow necessary for grain planting.

BACKGROUND: Due to the excessive vertical and angular vibrations of suspensionless vehicles used in agriculture and road construction that occur during movement, the velocity of their motion is limited, which, in the conditions of a constant traffic flow, reduces the road capacity. Therefore, the search for ways to improve the vibration-isolating properties of wheeled suspensionless vehicles is a relevant issue, the solution of which affects not only on traffic safety and driving comfort, but also on average speed and fuel efficiency.

AIMS: To determine the lateral stiffness of the pneumatic wheel from the rear axle of the MTZ-82 “Belarus” tractor at different tire pressures, basing on bench tests.

METHODS: On the basis of the hydraulic pulsation test rig of the Automatic Units department of the VolgGTU, a special-purpose movable supporting and measuring device was developed and assembled, the feature of which is that 4 rollers with flanges are installed on top of the hydraulic actuator force sensor, a flat rectangular base plate is supported on these rollers and connected with a vertical frame of the rig through a force-measuring device by means of a screw mechanism. The tested wheel is mounted on the base plate, the wheel’s axle is fixed on a vertically-moving traverse, on top of which weights creating the necessary vertical force are fixed. The test procedure consisted in measuring the lateral force and lateral displacement of the base plate until the tire slip occurred at the following tire pressures: at the recommended pressure of 0.16 MPa and at reduced pressures of 0.12, 0.08 and 0.04 MPa.

RESULTS: Based on the test results, the elastic characteristic curves of the lateral stiffness of the tested wheel were obtained. These characteristic curves have a regressive form, as their slope significantly decreases with a significant reduce in tire pressure. Thus, when the tire pressure is reduced from 0.16 to 0.12 MPa, there is practically no difference in the obtained values of lateral stiffness, which reaches 112.5 kN/m. After a 2-fold tire pressure reduction, the lateral stiffness decreases by 7%, and after a 4-fold reduction, by 28%. At the same time, the static tire deflection increases from 22 to 32 mm, which significantly increases the contact patch of the tire with the ground.

CONCLUSIONS: By means of the tests carried out, it is established that tire pressure reduction by 25–50% of the recommended value does not have a significant effect on the loss of lateral stiffness of the pneumatic wheel of the rear axle of the MTZ-82 “Belarus” tractor, which is important to use in order to increase traction and improve ride comfort of wheeled tractors.

BACKGROUND: One of the relevant issues to study is the motion of a cotton-harvesting machine (CHM) at the turning lanes of the cotton field along curvilinear path. At the same time, the CHM’s wheels rolling occurs with lateral slip of tires, so the machine may have unacceptable, according to the conditions for raw cotton harvesting, deviations in the lateral direction of the motion path when turning to enter the beds of the cotton field, and the traction performance of the CHM’s steered wheels declines significantly.

AIMS: Building mathematical models and carrying out kinematic simulations to determine the motion parameters and the values of lateral forces, the side slip resistance coefficients of tires of the CHM’s guide wheels necessary to achieve the required performance and to maintain the specified accuracy of the path motion along the headland of the cotton field with acceptable traction indicators.

METHODS: Dynamic processes are hugely complicated and difficult to analyze in full. The developed models are based on the balance equations and the wheels motion is not considered separately, taking into account tire deflections.

RESULTS: The kinematic scheme of turning of the MKh-1.8 CHM with front driving and rear steered wheels was considered. It was assumed that the MKh-1.8 CHM moves at a low constant velocity, so the centrifugal force can be neglected. In addition, lateral slip is the very parameter that reflects the impact of external force factors that go with the curvilinear motion on the machine.

CONCLUSIONS: Analyzing the obtained results, the following can be noted: during the curvilinear motion of the CHM, the main parameters that determine the turning of the machine are the CHM wheelbase, the average steering angle of the steered wheels and the slip angles of the rear axle. Moreover, it should be noted that the slip angles of the front and rear axles of the CHM, their values and change have a significant impact on the machine turning kinematics. The presence of lateral slip is the main reason of significant deviations from the given path of the CHM motion at a headland of a cotton field.