Study Of Acceleration Slip Regulation For Four Wheel Drive Hybrid Electric Car

Acceleration Slip Regulation can reduce tire wear, improve dynamic performance and lateral stability of the vehicle by preventing driving-wheels from excessive slip. Compared with traditional four-wheel driving cars, the paper takes the four-wheel driving hybrid vehicles equipped with multi-power source which include engine, ISG motor and in-wheel motor as the object. As the drive feature has changed a lot and the way to coordinate each power torque is different, it is necessary to study further drive torque control strategy of the four-wheel driving hybrid cars.Taking the “Modeling--Design Control Strategy--Simulation--RCP” as the train of thought, this paper studies on the slip phenomena for each driving wheel of the hybrid vehicle, and develops the ASR control strategy for the HEV, then the off-line simulation is accomplished. Finally, the rapid control prototype simulation test for the control strategy based on d SPACE real-time system is implemented. The main research work is summarized as following:(1)According to the composition and structure of the hybrid vehicle and the needs for ASR research, the Engine model, ISG motor model, tire model using magic formula are built based on experimental data respectively, and power train model, seven-DOF vehicle dynamics model are developed based on physical logic on the platform of Matlab/Simulink.(2)The target driving torque control strategy and power coordinated torque distribution control strategy are made after analyzing the work mode of the HEV. Determine the optimal driving torque for the driving wheel through some parameters such as the velocity, slip rate and so on, based on the sliding mode variable structure control algorithm. With the engine optimal economic efficiency as the goal, according to the fuzzy control algorithm, using the advantage of the in-wheel motor and ISG motor’s quick response to coordinatly distribute the torque reasonably.(3)Based on the platform of Matlab/Simulink, off-line simulation analysis for the control strategy is implemented on four kinds of typical road conditions-- low-mu road, the split road,mu-jumped road and checkerboard-mu road respectively under the circumstance of high SOC and low SOC.(4) The rapid control prototype simulation test is made based on d SPACE real-time system and test bench to validate the feasibility and real-time of the control algorithm and strategy.The simulation results indicate that the control strategy can effectively prevent driving-wheels from slipping excessively and improve the power performance, driving stability and fuel economy on four kinds of typical road conditions, as well as that the control strategy is of the feasibility and real-time.