Integrated AFS and ARS Control based on Estimated Vehicle Lateral Stability Regions

An integrated control design consisting of active front-wheel steering (AFS) and active rear-wheel steering (ARS) based on estimated lateral stability regions is presented in this paper. Both AFS and ARS technologies show their positive impacts on improving vehicle dynamic control performance. However, tire saturation, which is known as one issue of steering based assistant systems, severely limits the capability and effectiveness of the two methods for some extreme driving conditions. Moreover, most of existing ARS control algorithms are dependent on the vehicle longitudinal velocity, which is utilized as thresholds to determine rear steering directions for different control purposes. To avoid the issue of tire saturation and remove the longitudinal speed threshold, an integrated AFS and ARS control design is proposed based on estimated stability regions, in which vehicle longitudinal velocity and tire saturation have already been considered and analyzed. The effectiveness of proposed control algorithm is demonstrated through Car Sim^®/Simulink^® co-simulation results of different driving maneuvers.