High Accurate Position Control Of AMT Shifting Actator Based On Fuzzy Rules

Automatic transmission technology is one of the key research fields in vehicle power train system. Compared with the Hydraulic automatic transmission, the automatic mechanical transmission (AMT) has much lower cost in manufacturing and more convenient for assembly in the driveline system. This means that there is a huge potential market for the implementation of such a mechatronical technology. Presenting as a key functional module in AMT system, the gearshift actuating mechanism needs to overcome some hurdles. For example, gearshift operation is inaccurate, unreliable, and can't be massively produced. Based on a project funded by the science and technology commission of Shanghai, this research makes a thorough investigation and experiment on the gear shifting process.The gear shift system is a hydraulic-electronic controlled unit. The linchpin of gear shifting is controlling the mechanism to the neutral position. The dynamic equations of the gearshift process are established firstly. Then a system model is built in MATLAB/SIMULINK and validated by the experiment data.The nonlinearity characteristic of hydraulic system and the lag operation of the electromagnetic valves are the main problems to be solved in the position control. Common PID control method can not achieve the desirable targets in these systems. So as an alternative, a fuzzy controller is designed and implemented with MATLAB/SIMULINK. The fuzzy rules are based on some experiments in which the relations among distance, position and opening time of the valve are studied. Also the experience of the manual transmission manipulators is employed.In order to validate the algorithm, some simulations are conducted. The simulations consist of the following factors: changes of the mechanism friction, variations of oil viscidity and electromagnetic valves'response time. The results show that the fuzzy control algorithm is adaptive for the changes of mechanism friction and oil viscidity. Moreover, electromagnetic valves with faster response ability can shorten the system's response time and decrease the steady-state deviation.To validate the control algorithm, the static and dynamic experiments were conducted in Shanghai automotive gear workshop (SAGW) and Shanghai KinWay Technology Corporation respectively. The gearshift process under the static work condition was checked in static experiment. The dynamic gearshift process was carried out in the dynamic experiment, in which the output shaft is loaded and rotating. The results indicate that the mechanism can shift accurately to the target gear position during the required time. The overshot and the steady-state error are within the neutral gear bound. In this study, the control algorithm can improve the gear shift performance and provides a good alternative solution to the AMT gearshift mechanism control.