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Dual Clutch Automatic Transmission (DCT) has the characteristics of light weight, fast shift speed and high transmission efficiency. Electric vehicles equipped with dual clutch transmission can effectively improve vehicle power performance and economy. Electro-hydraulic control system, as a key component of transmission, determines the quality of shift. In this paper, an electro - hydraulic control system is designed based on two - speed dry dual clutch transmission of electric vehicle. Firstly, the hydraulic components of the system were selected and calculated based on the vehicle parameters. Secondly, the electro-hydraulic control system of the dual clutch transmission was established according to the transmission control strategy and the matching hydraulic valve body assembly was designed. Then, the key components of the system were simulated to analyze their dynamic shift characteristics and response characteristics.

In order to improve the drivability and reduce the clutch friction loss, low-cost slope sensor is used in hill-start control of AMT vehicles. After the power spectrum analysis of the original signal and the design of the digital filter, the angle of the slope is obtained with short enough delay and small enough noise. By using this slope angle information, slope resistance force can be calculated online so that the vehicle can be prevented from sliding backward and optimal launch control can be realized. The digital filter of slope angle signal and the optimal controller of dry clutch engagement are embedded in the TCU (Transmission Control Unit) of a micro-car Geely Panda. Real-vehicle experiments are carried out with optimal clutch controller, which shows that the hill-start with low-cost slope sensor and optimal clutch controller can provide successful vehicle launch with little driveline shock. In addition, it can also avoid backward sliding and engine over-speed effectively.

In order to achieve a good shifting quality of pure electric vehicle dual-clutch transmission, this paper adopts linear active disturbance rejection controller (LADRC) to control the shifting strategy. For the uncertainty of transmission dynamics model parameters and the existence of unknown disturbance effects, the linear expansion state observer (LESO) can be used to estimate and compensate the disturbance. The shift control process is converted into tracking the motor speed and clutch speed trajectory, and the linear feedback control law is used to control the motor torque and the solenoid valve current. The simulation and test results show that the control algorithm is effective and good shifting quality is guaranteed.