Abstract:Considering the fact that the tracked combine inclined with the undulation of the terrain when it worked on the uneven ground, which resulted in the reduction of the working efficiency, the poor driving comfort and the low safety of the manipulator, a kind of posture controlled chassis of the tracked combine was designed. The chassis was composed of upper frame, lower frame, lifting mechanism and electrohydraulic control system, which can realize automatic and manual adjustment when the combine chassis tilted. The longitudinal adjustment range was -5°~ 7°, the transverse adjustment range was -6.5°~ 6.5°, the maximum lifting height of the chassis was 130mm. The working principle of posture controlled chassis, the structure of electrohydraulic control system and leveling control strategy were described, and then static and dynamic leveling verification tests for chassis performance were carried out. The static leveling test was carried out on the eight tilting states of the chassis: the lowest in front, the lowest in rear, the lowest in left, the lowest in right, the lowest in front, the lowest in right, the lowest in rear and the lowest in right. The test result showed that the maximum adjustment time of the automatic leveling system was 8.2s, the average adjustment time was 4.2s, and the maximum inclination error was 0.67°. The dynamic leveling experiment was carried out for three leveling control modes: automatic leveling control, manual leveling control and fixed gap leveling control. In the experiment of slope and furrow field, the automatic leveling control mode can improve the tilt state of chassis and the stability of chassis. The manual leveling control mode had a certain adjustment effect, but the adjustment stability was poor. In the paddy field experiment, the leveling effect of the automatic leveling control mode was better than that of the slope and furrow fields, which showed that the leveling performance of the automatic leveling control system was better under the condition of small terrain fluctuation. The dynamic leveling test showed that the automatic leveling system can reduce the inclination of the chassis, improve the stability of the chassis and enhance the adaptability of the combine to the uneven ground.