EXPERIMENTAL STUDIES OF THE DYNAMICS OF TURNING OF THE INTEGRATED GENERAL PURPOSE ROW CROP WHEEL TRACTOR
Machine and tractor units (MTU) in the field environment perform daily an operation on a long distance, when the driving strokes are accompanied and alternated with idle rides and turns, during which the rolling conditions of the wheels deteriorate, the resistance forces increase when interacting with soft ground, and the normal reactions are unevenly distributed over them. So, due to the abovementioned road stability is disturbed and the tractor driving qualities at curvilinear motion become progressively worse. Therefore, it is an important issue to adopt rational method of MTU motion on the headland, which allows softening dynamic processes. The authors conducted experimental studies of the combined mounted unit during its motion on the headland in a number of ways: (i) front steer wheels; (ii) front and rear steer wheels with synchronous change in the steering angle of the wheels in all directions above the frame of the tractor; (iii) combined steering motion with synchronous change in the steering angle of the wheels in one direction above the frame of the tractor at the beginning of the turn and the front steer wheels in the area of stabilized steering motion. It was revealed that front and rear mounted attachements contribute to an increase in vertical, longitudinal and lateral forces, and an increase in the amplitudes of their oscillations. The maximum torque values of the combined MTU increased by 32-35%in comparison with the tractor when the MTU was turning by front steer wheels at the stage of coming into the corner when the travel speed was changed from 0.68 to 1.37 m/s. The combined type of the MTU motion on the headland within the whole range of the travel speed allowed reducing the average torque values in the stage of steady steering motion by 17-21% in comparison with the first studied type of steering motion, by 6-9% in comparison with the second studied type of steering motion, and energy consumption of the MTA, respectively, by 13-22% and 10-13%.