Abstract
The relevance of developing analytical methods for studying the stability of root crop cleaners on tractors is determined by the need to improve the efficiency and quality of root crop head cleaning, as this affects the quality of the final product and its marketable properties. The research aims to increase the stability of the cleaner movement by constructing a mathematical model of its oscillatory motion in the longitudinal-vertical plane and its numerical solution to determine the influence of parameters in response to external disturbances. To achieve this goal, a new theory of the movement of a root crop head cleaner in the longitudinal-vertical plane, mounted behind a wheeled tractor, under the influence of the disturbing effect of irregularities in the longitudinal profile of the soil surface on the amplitude and phase frequency characteristics of its angular oscillations was developed. Using numerical calculations carried out on a personal computer, the conditions were found under which the stability of the cleaner’s movement in the specified plane will increase when the stiffness coefficient of the pneumatic tyres of the doubler wheels is 315 kN×m–1. This result is achieved when the pressure in the pneumatic wheel tyres is 135 kPa. As for the damping characteristics of the doubler wheel tyres, which are determined by the coefficient μ, it was found that when it changes from 350 N×s×m–1 to 1350 N×s×m–1, there is an invariance of the delay in the reaction of the cleaner to the disturbing effect when its frequencies change from 0 to 24 s–1. It was also found that the influence of the geometric dimensions of the cleaner is insignificant in the range of frequencies of oscillations of the ordinates of the longitudinal profile of soil surface irregularities from 0 to 24 s–1. This follows from the nature of changes in the obtained amplitude-frequency and phase-frequency characteristics. The methodology for constructing a mathematical model of the plane-parallel oscillatory motion of the cleaner can be used in similar analytical studies of other agricultural machines mounted on a wheeled aggregating tractor