Abstract:The active steering system can provide steering intervention to improve the vehicle handling stability. In order to improve the vehicle stability, a rear wheel active pulsed steering system was proposed and its performance was analyzed and verified by simulation and vehicle test. Firstly, a hydraulic pulsed steering system was designed and modeled. A simplified 2DOF vehicle model was considered as the analytical model, and a rear suspension ADAMS model with the hydraulic pulse actuator was developed. Secondly, the effect of the steering system on vehicle stability was studied and the pulse signal parameters (frequency and amplitude) were evaluated to determine their optimum values. And then, a control structure and algorithm were designed, and the simulations were addressed based on CarSim and Simulink to verify the performance of the proposed system. Finally, a set of hydraulic pulse steering device was designed and assembled to carry out road experiments to assess the applicability of the proposed system. Results from simulation and test indicated considerable improvements in vehicle yaw stability can be achieved and also the roll angle was reduced for improving the vehicle rollover ability. Sideslip angle and lateral acceleration in the peak were reduced by 46.8% and 23.5%, which improved the vehicle lateral stability. Roll factor can be controlled in the set threshold limits \[-08,08\] and vehicle roll angle was decreased by 25.4%, the vehicle anti rollover ability was improved and showed a better control effect than the active steering system. The considerable improvements in vehicle stability can be achieved.
