Mathematical modeling of the cultivator machine-tractor unit

Abstract

The soil-cultivating machine-tractor unit undergoes continuously changing external influences that lead to fluctuations in the speed of movement, slippage of the tractor's driving wheels, loading of the transmission, and increased fuel consumption. The main sources of disturbances that cause the oscillations of the tractor are the unevenness of the traction resistance of the tillers and the unevenness of the field microprofile. The purpose of the research is to improve the process of functioning of the soil-processing machine-tractor unit by modeling of the influence of external action. The mathematical model of the process of operation of a wheeled tractor in the traction mode of operation is a machine-tractor unit in the form of a dynamic system with two input forces, determined by the load on the working elements and the roughness of the relief. The mathematical model includes the equations of the motor and the regulator, the clutch, the power transmission, the driving wheel and the longitudinal-vertical oscillations of the tractor. The solution of the mathematical model of the machine-tractor unit is based on the Runge-Kutta fourth-order method numerical integration method at a constant step. Calculations are made for the motion of the unit with periodic sinusoidal disturbances applied to the input of the model. As a result of calculations, it is determined that the effect of the microfield of the field and the traction resistance of the working bodies on the performance of the machine-tractor unit is different. The greatest amplitudes of vertical accelerations are achieved due to the effect of field unevenness. Fluctuations in the speed of movement, hectare fuel consumption, engine torque are caused by the periodic component of traction resistance of low frequency, and slippage and driving torque of the wheels - as well as unevenness of the field microfilm. The average values of the slippage of the tractor's driving wheels and hectare fuel consumption are mainly affected by the oscillations of the traction resistance. The use of diagonal-parallel tires instead of radial makes it possible to reduce the slipping of the tractor's drive wheels from 24 % (when working on serial tires) to 16 % (on test tires) and to reduce the hectare fuel consumption by 6 %.