Abstract:

In order to obtain the double motor fourwheel driving electric vehicles maximum driving force in different road surface, this paper proposes a traction control strategy based on LuGre friction dynamic model and a SMO(Sliding Mode Observer). Using LuGre dynamic model's parameter θ that react pavement condition to realize the pavement conditions online identification. By designing the SMO initiatively estimate the road condition parameters θ with small tire slip ratio while the electric vehicles in the vertical driving conditions. With the estimation optimal slip ratio, we can achieve the maximum traction provided by the road. We design dynamic saturated nonlinear control strategy to limit the maximum output torque of motor and to ensure the electric vehiclesanti-skidding under the different pavement conditions. The simulation results show that the optimal slip ratio estimation method based on sliding mode observer can provide maximum traction for electric vehicles under the different road conditions. The strategy is important in active safety of the electric vehicles driving.

Key words: electric vehicle, LuGre friction dynamics, sliding mode observer, traction control