MECHANIZATION IN AGRICULTURE
Mathematical modelling of oscillatory movements cleaner of the heads of root cultures from remains on the root
Harvesting root crops still poses a challenging problem for the agricultural mechanization industry. Even though the technology of separate harvesting of tops and roots has undoubted advantages, the quality of the final product, i.e. roots, depends significantly on the accuracy of cutting tops from their heads to the roots and the thoroughness of their final cleaning from residues. One of the ways to solve this problem is to create improved constructions of peelers and their further testing, experimental and theoretical studies to determine their optimal structural and kinematic parameters. To implement the above, a new mathematical model was constructed, the study of which made it possible to assess the influence of the construction parameters of the root crop head cleaner from the residues of tops on the root on the indicators of its oscillatory process in the longitudinal-vertical plane when moving along uneven soil surfaces. Numerical calculations of the obtained mathematical model were carried out on a PC using the PTC Mathcad 15 software environment and the previously determined input numerical parameters. The amplitude-frequency and phase-frequency characteristics were constructed, which made it possible to determine the optimal parameters of this oscillatory system. Based on the mathematical modelling performed, the influence of irregularities in the longitudinal profile of the soil surface on the angular oscillations of the cleaner, as well as the influence of different values of the stiffness coefficient c and the damping coefficient μ of its two copy wheels, as well as the length l, or the longitudinal coordinate of their placement on the cleaner frame, was first of all determined. The mathematical modelling of the oscillatory movements of the cleaner made it possible to establish that the value of the stiffness coefficient c of the pneumatic tires of its trailing wheels should be not less than 315 kNm–1, which is ensured by the air pressure in its tires, which should be equal to 135 kPa. In addition, it has been established that the change in the value of the coefficient μ of damping of the tires of the cleaner’s tracking wheels should be in the following range 350…1350 Nsm–1 and this parameter does not affect the amplitude and phase frequency characteristics of oscillations under the influence of oscillations of the ordinates of the longitudinal profile of field surface irregularities in the frequency range 0…24 s–1. Also, the influence of oscillations of the longitudinal profile ordinates of the field in the specified frequency range of 0…24 s–1 depends little on the change in the value of the longitudinal coordinate l of the location of its tracing wheels. Therefore, the placement of the tracing wheels on the frame should be determined based on the constructional features of the cleaner.