Mathematical model of passive withdrawal of a tractor unit

Introduction. External forces from the working implements of tractor units or road construction machines often lead to uncontrollable displacement from a given trajectory. This movement is the sum of controlled movement and uncontrolled displacement (start of moving). The lack of adequate models of displacement (start of movement) is the reason for the insufficient study of uncontrolled movement at the present time. The goal is to build a model of uncontrolled displacement under the action of an external force, which allows obtaining the maximum value of the external force, depending on its direction.Materials and methods. The mathematical model of limiting equilibrium is built on the example of a bulldozer unit with a skewed blade. The force factors of the interaction of the mover with the soil included in the model were formed on the basis of the mathematical theory of friction. The model was improved by introducing different coefficients of adhesion in the longitudinal and transverse directions. This made it possible to take into account the anisotropy of the interaction of the propeller with the ground.Results. The hodograph of the limiting shift force was constructed as a result of a numerical experiment. His analysis showed that the shift force is equal to the adhesion limit only in the case of translational shear. In all other cases (instantaneous rotational shear) the value of the ultimate shift force is less than the adhesion limit. Anisotropy further reduces the value of the limiting external shear force and rotates the hodograph towards the lowest friction coefficient.Conclusion. The hodograph allows calculating the value of the limiting shear force and assessing the possibility of an uncontrolled deviation of the machine from a given trajectory. The resulting model will subsequently be used to build a control system for the operation of an unmanned vehicle, taking into account the external influence from the working tools.

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Experimental studies of the uncontrolled shift of the bulldozer

Troyanovskaya

Zhakov

2022

Vestn. SibADI

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Introduction. External forces from the working body of a road-building machine sometimes lead to its uncontrolled deviation from a given trajectory when performing a technological cycle. In this case, there is a clear dependence of the magnitude of the shift force on its direction. The purpose of experimental studies was to determine the values of the limiting shift force for its various directions.Materials and methods. The experimental tests were carried out on the example of a 10-ton caterpillar bulldozer manufactured by the Chelyabinsk Tractor Plant. The shift was carried out by the action of an external force applied to the edge of the dump in various directions. The external force was recorded on an oscillogram.Results. The shift began with an external force equal to the adhesion limit, provided that the line of action of the external force passed through the center of pressure. The shift begins at much lower values of the external force when the line of action of the external force deviates from the center of pressure. The result of the experiment was the construction of a hodograph of the limiting shift force.Conclusion. The nature of the change in the external force during translational and rotational shear was fundamentally different. It has been experimentally confirmed that the more the direction of the shear force deviates from the center of pressure of the machine, the smaller the value of the external force can lead to an uncontrolled shear.

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Mathematical model of passive withdrawal of a tractor unit

Cited by 3 publications

References 15 publications

Method for Calculating the Limiting Shear Force Deviating from a Given Direction of Movement Using the Example of the B12 Bulldozer

Method for Calculating the Limiting Shear Force Deviating from a Given Direction of Movement Using the Example of the B12 Bulldozer

Model of uncontrolled displacement on the example of road construction machines

Experimental studies of the uncontrolled shift of the bulldozer

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