Study of Acceleration Slip Regulation Strategy for Four Wheel Drive Hybrid Electric Car

Abstract

The use of multiple power sources not only increases the modulation means of driving wheel torque,but also brings a new challenge to the acceleration slip regulation(ASR) realized by relying on conventional anti-lock braking system(ABS).Aiming at four wheel drive hybrid electric car,a powertrain forward simulation model is built with consideration of the nonlinear seven degree-of-freedom vehicle longitudinal dynamics.Using the electric motor characterized by the accurate control and rapid response of torque to adjust the torque of slipping wheel,and based on the existing energy management strategy validated in the real vehicle,ASR control algorithms of logic threshold and P-Fuzzy-PI having the qualities of multi-mode and time-sharing are respectively developed,offline simulation is conducted under the two running cases of pure electric launching and hybrid propulsion emergence acceleration at the low adhesion coefficient road.Afterwards,front wheel speed sensor signals are acquired by the hybrid control unit(HCU)and ASR is integrated into HCU,real vehicle anti-slip test is performed on the snow/ice road.Simulation and test results indicate that the proposed two kinds of anti-slip strategies can effectively prohibit the driven wheel from transient slipping,so the scheme that ASR strategy can be integrated into the energy management strategy and be carried out in the HCU is feasible and effective.