Development of a four-point adjustable lifting crawler chassis and experiments in a combine harvester

In agriculture, the body tilt of vehicles or platforms can be controlled by levelling technology to prevent rollover and improve efficiency when operated in rough terrain. Many researchers have carried out important study in this area based on mechanism development and optimization, but most of them are not effective to crawler vehicles. The objective of this research was to specifically develop a levelling mechanism for crawler combine harvester, since as a consequence, enhancing the operation performance and trafficability. This levelling method depends on a hydraulic four-point adjustable lifting chassis, which could adjust vehicle chassis by controlling hydraulic cylinders. Therefore, the mathematical models between chassis attitude (including ground clearance, the horizontal and longitudinal inclination angle) and each length of hydraulic cylinder were deduced. The principle of lifting mechanism of crawler vehicle chassis was analyzed by using virtual prototyping software ADAMS, as well as dynamic performance under three different attitude adjustment conditions. The maximum adjustment range of the ground clearance is 140 mm and the lateral inclination adjustment range is ±5.17°. Experiment showed that the designed levelling mechanism was feasible and with positive significance for crawler vehicles levelling.