Active front wheel steering model and controller for integrated dynamics control systems



We report a model and controller for an active front-wheel steering (AFS) system. Two integrated dynamics control (IDC) systems are designed to investigate the performance of the AFS system when integrated with braking and steering systems. An 8-degrees-of-freedom vehicle model was employed to test the controllers. The controllers were inspected and compared under different driving and road conditions, with and without braking input, and with and without steering input. The results show that the AFS system performs kinematic steering assistance function and kinematic stabilisation function very well. Three controllers allowed the yaw rate to accurately follow a reference yaw rate, improving the lateral stability. The two IDC systems improved the lateral stability and vehicle control and were effective in reducing the sideslip angle.

Key words

Active Front wheel Steer (AFS) Active Rear wheel Steer (ARS) Integrate Dynamics Control (IDC) Direct Yaw moment Control (DYC) Yaw rate Body side slip angle 



distance from center of gravity to front wheel = 1.35 m


area of master cylinder = pi × 0.022 m2


distance from center of gravity to rear wheel = 1.36 m

Cf, Cr

front and rear axle cornering stiffnesses = 105,850.0 N/rad, 79,030.0 N/rad

Cαf, Cαr

lateral stiffness of the front and rear tires = 30,000 N/rad


roll axis torsional damping = 3,511.6 Nm/rad/s


rolling resistance coefficient

Ft, Fx, Fy

tire tractive, longitudinal, lateral force (N)


normal force (N)


distance between roll axis and center of gravity = 0.2 m


mass moment inertia of the wheel about the axis of rotation = 2.1 kg m2

Ixx, Izz

vehicle inertia moment about the roll/yaw axis = 489.9 kg m2, 1,627 kg m2


roll axis torsional stiffness = 66,185 Nm/rad


sprung mass = 1,160 kg


vehicle total mass = 1,210 kg


brake fluid pressure (N/m2)


distance from the centre of the wheel to the brake path = 0.16 m


wheel radius = 0.3 m

tf, tr

front and rear wheel track = 1.55 m

vx, vy

velocity of longitudinal/lateral direction (m/s)


body slip angle (rad)


roll angle (rad)


yaw angle (rad)


wheel rotational velocity (rad/s)


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Copyright information

© The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Department of Mechatronics EngineeringTongmyong UniversityBusanKorea

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