Handling enhancement of a sliding-mode control assisted four-wheel steer vehicle

This paper is an investigation of the role of the robust control strategy of the rear wheel steer system to improve handling. To establish an accurate model of the vehicle, a nine degree-of-freedom (DOF) model is considered. The model’s degrees of freedom consist of three angular motions (roll, pitch, and yaw) of the sprung mass, spin of the wheels, and two translational motions (forward and side travel) of the unsprung mass. Also, the environment and geometric effects, such as aerodynamic forces, tyre–ground interaction, body roll versus camber relation, steering command saturation, and roll axis inclination, are taken into account. The front and rear suspensions are assumed to be a MacPherson strut and semi-trailing arm respectively. Cornering behaviour of the vehicle is studied and compared for a manual two-wheel steer (2WS) and a sliding-mode control assisted four-wheel steer (4WS) vehicle. A 3-DOF vehicle model is used to make a fast state estimation. The yaw rate is used as the reference signal for the control system, to ensure that the desired handling is obtained. The results show that during the standard cornering manoeuvres, the sliding-mode control provides significant tracking performance and lower sensitivity to vehicle velocity, road condition, and roll axis inclination compared to the 2WS. Also lane tracking and cornering behaviour of the steering system is enhanced towards the neutral steer.

[1]  Jörnsen Reimpell,et al.  The Automotive Chassis: Engineering Principles , 1995 .

[2]  Haruo Shimosaka,et al.  Study on a four wheel steering vehicle driven at an objective side slip angle , 1994 .

[3]  Weiping Li,et al.  Applied Nonlinear Control , 1991 .

[4]  Manfred Plöchl,et al.  DIFFERENT ACTUATION STRATEGIES FOR A YAW MOMENT CONTROL OF A PASSENGER CAR , 2001 .

[5]  韩强,et al.  THREE DIMENSIONAL MODELING AND DYNAMIC ANALYSIS OF FOUR—WHEEL—STEERING VEHICLES , 2003 .

[6]  Ning Chen,et al.  On fractional control method for four-wheel-steering vehicle , 2009 .

[7]  Ahmed El Hajjaji,et al.  Four wheel steering control by fuzzy approach , 2005, J. Intell. Robotic Syst..

[8]  Mohammad Farrokhi,et al.  Hybrid state-feedback sliding-mode controller using fuzzy logic for four-wheel-steering vehicles , 2009 .

[9]  M. A. El-Nashar,et al.  Enhanced Vehicle Lateral Stability in Crosswind by Limited State Kalman Filter Four Wheel Steering System , 2007 .

[10]  Evren Ozatay,et al.  Enhancement of Vehicle Handling using Four Wheel Steering Control Strategy , 2006 .

[11]  Aleksander B. Hac.  ROLLOVER STABILITY INDEX INCLUDING EFFECTS OF SUSPENSION DESIGN. IN: OCCUPANT AND VEHICLE RESPONSES IN ROLLOVERS , 2002 .

[12]  Tor Arne Johansen,et al.  On non-linear unknown input observers–applied to lateral vehicle velocity estimation on banked roads , 2007, Int. J. Control.

[13]  Giancarlo Genta,et al.  The Automotive Chassis , 2020, Mechanical Engineering Series.