Currently, loosening and separating machines that combine the operations of crumbling and separating of soil according to the treated layer depth have come to the forefront. Interaction of the rotor blade of these machines with the soil comprises three stages: soil core formation; steady movement; and dumping of soil from the separating grid. The article determined the direction and magnitude of soil displacement, parameters and shape of the furrow formed after the ripper passage. Based on theoretical research, a mathematical model of the interaction of working bodies with the soil was developed. The initial data were obtained experimentally, and the model was justified. As a result, it was found that the supplied soil layer thickness and the fracture angle of ripper have the greatest influence on the transporting capacity of rotor ripper. Reducing the rotor blade entry angle into the soil from 45° to 30° made it possible to raise the second soil feed of the loosening and separating machine by more than 40 times. The width of rotor ripper practically does not affect the transporting capacity. Changing the angle of ripper entry into the soil allowed obtaining of the required transporting capacity of ripping and separating machine without changing the rotor design. Practical significance of the study lies in the possibility of increasing the work productivity without increasing its energy indicators.

Introduction. Production of safe food requires the avoidance of using chemical means to bring weeds under control in cultivating crops. Existing tillage loosening and separating machine PRSM-5 Dokuchaevskaya optimizes the physical and mechanical state of the cultivated soil layer, while the weeds are carefully removed from the soil by combing out together with the whole weed root system and laid on the surface, where they dry up under the influence of climatic factors. During the operation of the tillage machine, about 30% of the total energy consumption is spent on the rotor drive. Therefore, this machine is not working satisfactorily in firm soils. Materials and Methods. The soil was considered as an elastic-plastic medium. The generalized Hookeʼs law model and a variant of the plastic flow theory were taken into account. To simplify the calculations, there was used the experimental study information on the position in space of the soil deformation surface. The intensity of stresses of polyplastic deformations of the soil layer was determined. For the numerical solution of the problem, the Ritz method was used. Results. In connection with the indicated disadvantages, the parameters of the rotor ripper are justified taking into account the reduction in energy consumption for its drive. As a result of solving the problem by the Ritz method, the geometric shape of the rotor ripper was determined. The energy performance of the section of the tillage machine was evaluated by the torque of the rotor drive of the loosening-separating device. The rotor drive torque was determined for rippers with flat, convex, and concave profiles and for the profile substantiated during the study. Discussion and Conclusion. The profile substantiated during the study provides the best conditions for transporting the soil at the initial moment of the rotor entry into the soil and the minimum energy consumption for its drive.

The authors consider the procedure of building mathematical models of stability of mechanical systems functioning as described in Lyapunov theory used for solving the tasks of agricultural mechanics. The authors describe the results of agricultural machines operation analysis. The authors build the dependencies which can help define soil pulverization angle for various tillage depths based on the given parameters. These dependencies help define the parameters of dynamical systems reducing their energy consumption, improving qualitative indicators and creating the conditions for equipment performance improvement. The described model of the physical essence of wedge-soil interaction process is widely used for solving various tasks of justification the parameters of tilling mechanisms. However, the physical essence of processes occurring in the tilled soil layer under the influence of a wedge has not been studied sufficiently enough. When using any stability theory, it is important to define ultimate strain values causing material deformations leading to the destruction of the initial structure. Ultimate stress values can be easily defined by experiment only for stretching strain and compressional strain. Consequently, to define the strains occurring in soil under the influence of wedge, we can accept a hypothesis that a tilled soil layer splits away from the elastic mass by bending.  

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