Based on Virtual Prototyping of Active Front Steering Control

Steering system directly affects the performance of vehicle handling and stability, is to ensure the safety car at high speed is an important performance. Steering system can not meet the traditional low speed flexibility and high speed stability requirements.Active front steering vehicle traveling state can achieve the desired steering ratio, while simultaneously the flexibility to meet the low-speed stability and high speed requirements. Retention of active front steering system with mechanical connections, the driver can feel the real "road feel." Therefore, the flexibility of driving, comfort, stability and security considerations, active front steering system steering is today an important direction of research and development. In this paper, ADMAS / Car platform, built for active front steering of the vehicle model. By turning the sine sweep test simulation to verify the correctness of the model built vehicle. In the low friction coefficient and high friction coefficient road test under the separate hunting simulation results show that: in the extreme conditions, vehicle yaw rate and sideslip angle response to steering wheel angle can change with the car is easy to lose stability. In this paper, a robust nonlinear fuzzy PID control model of vehicle stability control, cornering performance to a satisfactory model of two degrees of freedom as a reference model. The fuzzy PID controller yaw rate and sideslip angle as control targets to vehicle yaw rate model and the ideal difference between the yaw rate as the control variable. Tolerance approach by the stability of the car to judge, the use of ADAMS / Car and MATLAB / Simulink software co-simulation of two. Simulation results show that: Active Front Steering Vehicle Stability Control to expand the area to prevent vehicles advance into the nonlinear region and saturation regions, especially in excessive steering condition, the control effect relatively clear. As conditions in the limit tire slip forces are easily filled, active front steering to improve vehicle stability control system of limited, so this paper, active front steering and variable torque distribution of the need for joint control. Design of active front steering and variable torque distribution joint control of the fuzzy controller.Controller to vehicle yaw rate model and the ideal difference between the yaw rate and vehicle sideslip angle model as input variables, the previous round of the overlay and the additional yaw moment angle as output variables. Using phase plane method of tolerance zones and to determine whether the car unstable. In the face of low adhesion road control system for a double lane for simulation, simulation results show that: joint control can keep the car's stability, its effect is superior to separate active front steering control, sideslip angle and horizontal control the swing angular velocity response are ideal range. 

 

Keywords: active front steering; fuzzy PID control; variable torque distribution; co-simulation