Road holding ability of machine-tractor unit during plowing

Abstract

The discrepancy between the working width of the plow and the width of the tractor leads to asymmetry of the arable units. The geometry of the share surface of the reversible plow contributes to the generation of lateral forces on the working tool. All this contributes to the imbalance of the working body and the deviation of the tractor from straight-line movement during plowing. To maintain a straight line, the driver has to correct the vehicle movement every 5-10 meters, which makes him more tired. To study the causes of lateral slip of the plowing unit, a mathematical model was built. It consists of the equations of controlled motion and equations of uncontrolled shift of the tractor under the action of external forces from the plow. The description of the force interaction of the propeller with the ground is based on the mathematical theory of friction, taking into account anisotropy and elastic properties in contact. On the basis of the passive shear model, the hodograph of the maximum force shifting the tractor from the side of the working tool is constructed. It has been established that the shear force reaches its maximum adhesion value only in the case of trans-lational shear, when its line of action passes through the center of gravity of the tractor. In all other cases, the shift (pull) of the tractor is carried out by a force of a lower value. The features and as-sumptions of the model are formulated in relation to the tracked and wheeled tractors. As a result, it was found that regardless of the direction of the lateral displacement of the plow draft resistance, the tractor is pulled towards the plowed field. The result of the numerical experiment showed that the main reason for the drift of the wheeled arable unit is the different type of soil along the sides of the tractor, but not the displacement of the plow traction resistance.