Method for the influence design assessment of a wheeled agricultural vehicle on the soil

The impact of a wheeled agricultural vehicle on the deformable support surface determines the vehicle's ability to move, as well as soil compaction, which is not desirable in agriculture. The agricultural machine must not cause more pressure on the ground than is permissible. Therefore, in the tasks of design numerical modelling of the agricultural vehicle movement or trailer, it is required to calculate the specified parameter. It is impossible to calculate without knowledge of the geometric characteristics of the contact spot associated with the normal deformation of the tire under normal load. To calculate these characteristics, it is necessary to have universal dependencies for determining the normal stiffness of the tire. These are available for tires of various purposes. The elastic properties of ultra-low pressure tires are insufficiently studied. Experimental studies of the elastic properties of these tires have been carried out with the authors participation. However, there are currently no dependencies to describe them. This does not provide the possibility of a correct design calculation of the influence of such tires on the soil. The purpose of the work: to develop a universal method for calculating the influence on the soil of agricultural vehicle. A universal method for calculating the impact of a wheeled agricultural machine on the ground has been developed. Universal design-experimental dependence for determining the normal stiffness of ultra-low pressure tires is obtained. It takes into account tire pressure, normal load under specific conditions and geometric characteristics.

Algorithm of the dynamic functional of the adaptive torque distributor as applied to agricultural machines

The article deals with the problem of improving the drive of the driving wheels and working bodies of agricultural machines. The analysis of works on the research topic showed that this problem is solved by giving the very executive mechanisms of the agricultural machine the ability to adjust the characteristics in the direction that improves certain indicators of the quality of functioning, by the purpose of which it is possible to judge the efficiency of the operation of such a machine. The flexibility of the structure can only be ensured by the presence of additional degrees of mobility. Therefore, it is proposed to use differential mechanisms of varying complexity in the drive, which will provide continuous automatic regulation of its own operating parameters depending on changes in the resistance of the working medium to the executive bodies of the machine.

Determining the temperature values on the surface of complex curvilinearly bent agricultural machine parts during the formation of powder coatings by thermal methods

The development of modern technologies for the restoration and hardening of agricultural machine parts require the development of a mathematical apparatus that simulates the involved processes. For this purpose, the models should take into account the technological features of the process of hardening and restoration of machine parts, including: cleaning; determination of geometric indicators; surface preparation; choice of technology; subsequent machining of the resulting surface; surface quality control. One of the priority directions in the development of technologies for the restoration and hardening of parts is the formation of coatings on machine parts using powder materials applied by the gas-thermal method. One of the most important conditions for obtaining high-quality coatings is temperature control on the surface of the part. In this regard, it is of scientific interest to study the effect of the distance from the surface of the part to the flame nozzle when applying self-fluxing powder on the time-average temperature at the point of coating, the maximum temperature on the back side of the part, and the total power transferred to the part by the gas burner. This paper presents a mathematical model for determining the above-mentioned influence, and also presents the results obtained using a computer program. The novelty of the model is the ability to use it to study temperature values for complex curved-bent machine parts (crankshafts and camshafts of agricultural machines). To check the reliability of the dependences obtained, experiments were carried out and the convergence with theoretical developments was confirmed.

Development and Rationale of Two-Disk Operating Body of Agricultural Machine for Tillage

One of the main problems in the design of agricultural machines, including tillage machines, is to ensure the optimal energy intensity of various technological operations. The design, kinematic and technological parameters of rotary tillage machines have a significant impact on the indicators of the energy intensity of the process and the quality of tillage. These parameters include the diameter of the operating body of the agricultural machine, the angular speed and rotational speed of the disks, the number of cutting elements, the translational speed of the operating body, the height of the ridge formed during soil cultivation, the thickness of the cut chips. An important agrotechnical parameter of a rotary tillage machine is the ridging of the furrow bottom. The height of the ridges formed should not be less than 20 % of the depth of the cultivated soil. Currently, in order to ensure the required height of the ridges in the designs of rotary machines, there are a number of restrictions that determine the operating mode and parameters of the units. The degree of influence of the parameters of the developed operating body and the energy consumption on the quality of tillage has been assessed in the process of the research. The experiments have been carried out on an installation that included an operating body, a power unit, control and instrumentation equipment. As the power section, AC motors with a phase rotor were used, the power of which was 0.75 and 1.50 kW, and the speed of rotation was 920, 1500 and 3000 rpm. The parameters have been set that allow to reduce the energy consumption for tillage by 11–17 %, compared to existing machines, and ensure the alignment of the furrow bottom by up to 80 %.

Technical condition of the agricultural machine

In article material by definition of technical condition of the car/mechanism is provided. Operability definition is given, working capacity and technical condition of the car. Ways of digitization of these concepts are given.

A robust H∞-based steering assistance system for the wheeled tractor

Agricultural machine automatic navigation poses great challenge to the precise agricultural technology system nowadays. To this end, this paper proposes a novel steering assistance system (SAS) to assist drivers in the path-tracking. First, the driver steering model is investigated through the driver simulator tests. Combining the wheeled tractor kinematics model, a driver-vehicle model is developed. Then, a polytopic linear parameter-varying (LPV) system is adopted to describe the uncertainties, including time-varying driver model parameters and velocity, in the model, based on which an output-feedback robust controller is developed to ensure robust stability within the polytope space. Moreover, a regional pole placement method is adopted to improve the transient performance of the system. Finally, driver-in-the-loop and field tests conducted to value the controller. The results show the effectiveness of the proposed method to improve the path-tracking performance for the agricultural machine navigation, while reducing the physical and mental workload of drivers. This control method is expected to be a paradigm for the precise navigation system of the agricultural machinery.