Abstract: From the limited parameter of automatic mechanical transmission(AMT) control system, the road friction and slipping status of tires should be estimated, and tire slipping should be avoided by control; Calculating the vehicle reasonable acceleration by engine torque, transmission parameter and vehicle status, comparing with the wheel speed acceleration, it will confirm the wheel slipping status. The road friction can be confirmed by wheel acceleration rate. Tire driving slipping would be avoided by the control of decreasing engine torque and separating clutch when tire slipping; The road friction could be recognized by doing experiment on vehicle. The vehicle performance on low tire-road friction condition is upgraded by engine torque and clutch control when slipping. The results show that this method of friction recognized and slipping control is correct and can be used on vehicle.

Key words: Automatic mechanical transmission(AMT), Control strategy, Low friction road, Vehicle dynamics