Year: 2017 Volume: 1 Issue: 1 Page: 1-5
AN ACTIVE STEERING SYSTEM FOR ROAD VEHICLES
WAIZUDDIN AHMED, VAIBHAV RAWAT
Active steering systems for road vehicles are designed to generate and deploy a required angle at the wheels to realize a predetermined target response for a steering input at any forward velocity. For a typical vehicle with conventional steering system and understeer characteristics, this will demand an increase (correction) in the wheel steer angle as the velocity is increased. On the other hand, a handling maneuver at high speedswill lead to significant load shift from the inner to the outer wheel, which diminishes the ability of the inner tire to develop lateral force even if the steer angle is increased. This limits the performance potentials of active steering system if corrections are provided at both wheels following a fixed steering geometry. Recent studies have proposed active independent steering control where the steering correction can be introduced independently at a selected wheel. Such control strategy can thus also consider the tire work load at each wheel and in doing so, the correction can be applied to each wheel ensuring that none of tires approach its saturation limit. This paper presents sample results from a 4-wheel vehicle handling model to demonstrate the effectiveness of the active independent steering system over the fixed ratio conventional active steering system. A possible fail-safe mechanism that can be utilized to realize such control is also presented.
Anahtar Kelimeler (Keywords): Vehicle handling, Active steering, Independent steering, Steering mechanism