Improving Vehicle Handling Performance by a Closed-Loop 4WS Driving Controller

In this paper a closed-loop 4WS controller is proposed, which employs feedback control for both front and rear wheels. With an extra closed-loop steering control in series with the manual steering control for the front wheel, it is possible to achieve an enhanced vehicle transient handling response while eliminate the heavily oversteering tendency of the past 4WS system to achieve a driving handling feeling similar to a normal FWS vehicle. Comparisons have been made among the FWS, 4WS with zero side slip and this closed-loop 4WS system.