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Conventional agricultural chassis was difficult to adapt to the slope which put a severe test during the operation. Taking the auto leveling system as the research content, a twodegree of freedom platform and its selfcontrol system was developed. The mechanicalelectricalhydraulic multiphysics simulation model was established based on SimMechanics and SimHdraulics, which helped to analyze spatial kinematics through SimMechanics while hydraulic system simulation through SimHdraulics. Due to dualacting asymmetric hydraulic cylinders, a dualchannel PID control strategy was used to control following response, displacement error, velocity respectively and dualaxis inclination. The hydraulic cylinder with push and return movements could be regarded as different hydraulic cylinders with different piston areas. The characteristic of dualchannel PID control meant when errors were adjusted with different PID parameter values. The simulation results showed that the maximum following error was 1.90mm and the response time was 0.228s under dualchannel PID control. The equilibrium time in the limit state was 2.98s. Compared with singlechannel PID control, the maximum control error was reduced by 49.3%, and the response speed was increased by 45.8%. Tests under eight different gradients were performed. These results showed that the response time of the auto leveling system was 0.328s. With the increase of gradient, the maximum error of the test platform leveling was 1.14°, and the maximum root mean square error was 0.299°. The auto leveling system had a fast response, small following error, good followability and high control accuracy under the dualchannel PID control and it can meet the requirements of ring slope operation.