Study On Control Strategy For Automated Mechanical Transmission Of Tractor

With the continuous development of agricultural modernization in China, as themajor tool for farming work, the technical level of tractor needs to be improved. Thetraditional domestic tractor mostly adopts manual transmission, but it has someshortcomings such as difficult and complicated operating and it is easy to make driverfatigue. While tractor equipped with automated mechanical transmission (AMT) canmake up for these deficiencies, besides the improved working efficiency, tractor AMTalso offers many advantages in terms of good inheritance, low cost, easy tomanufacture, etc. For control strategy is the core content of the control system fortractor AMT, it has important significance to study on tractor AMT control strategy.Based on the elaborating of the structure and working principle of AMT system,the characteristic of tractor AMT power train is analyzed in this paper. Combined withdisk spring characteristic the torque-transferring characteristic curve of the tractorclutch is achieved. By the research of tractor dynamics the kinetic equation of tractorunit is deduced. The dynamic equation of tractor starting process is built, and thecontrol strategies of engine, clutch and actuator for tractor AMT in field startingcondition are designed. The shifting process of tractor is studied, and the optimalthree-parameter dynamic shifting rule for tractor field working condition is workingout. Then the control strategies of engine and clutch and combined shifting controlstrategy in shifting process are formulated. The simulation models of the power trainof tractor AMT are established by the using of Matlab/Simulink, and the simulationmodel of hydraulic circuit system is built by Simscape toolbox, then the multi-domainsimulation of the formulated tractor AMT system is done in Matlab environment. Afterthe analysis and comparison of the simulation results for starting and shifting processof the tractor with different slip rate, the validity of the control strategy is verified.This study can provide theoretical basis for the further research of tractor AMT controlstrategy.