The Active Independent Front Steering (AIFS) system is proposed in order to improve vehicle handling stability. The principle and structure of AIFS are introduced and the mathematical model of AIFS is built. The control strategy of AIFS is proposed and the controller includes two layers. The upper controller adopts PI control strategy and it calculates the total control angle according to the error of ideal yaw rate and actual vehicle yaw rate. The lower controller distinguishes the inner and outer road wheel, and calculates their respective steering angle. Simulation is carried out in MATLAB/Simulink to validate the effectiveness of control strategy. Simulation results show that AIFS has better performance in terms of improving vehicle handling stability compared with traditional active front steering for understeer vehicles.
[2] Koehn P, Eckrich M.Active steering-the BMW approach towards modern steering technology.SAE Technical Paper , 2004-01-1101,4.
[3] Tahami F,Farhangi S,Kazemi R.A fuzzy logic direct Yaw-moment control system for all-wheel-drive electric vehicles.Vehicle System Dynamics, 2004,1(3):203221.
[4] Li D F, Yu F.A novel integrated vehicle Chassis controller coordinating direct Yaw moment control and active steering.SAE Technical Paper, 2007-01-3642,7.
[5] Farazandeh A, Ahmed A K W,Rakheja S.Performance enhancement of road vehicles using active independent front steering (AIFS).SAE International Journal of Passenger Cars - Mechanical System, 2012,5(4).
[6] Bakker E,Nyborg L.Tyre modelling for use in vehicle dynamics studies.SAE Technical Paper, 870421,7.