Shifting Control of Heavy-Duty Planetary Transmission

To improve the vehicular shift quality and the heavy off-highway vehicle's performance, the vehicular equipped heavy-duty planetary transmission was analyzed, and a kinematic model of the testing automatic transmission with three degree of freedom was established. Then a shift control strategy was developed based on analyzing for the electro-hydraulic control system of the automatic transmission, and taking the shift clutch slipping which fused the turbine speed and the transmission output shaft speed as the control parameters. The difference of the vehicular acceleration, measured by a fiber optic gyroscope installed in the vehicular crew cabin, was used to evaluate the shift quality. Finally, the proposed control strategy was thoroughly verified on a heavy off-highway vehicle, excellent shift quality was achieved with the experimented data. And the contrast test show that the shift control quality by the clutch slipping is better than that controlled with the turbine speed.