Abstract
An electric power steering system (E.P.S) is replacing a hydraulic power steering system recently. Estimation of rack bar axial force during stationary steering is indispensable for system design, because not only the capacity of the motor, but also the layout of suspension and the system depend on maximum rack bar axial force. In order to estimate the accurate rack bar axial force, new method is developed based on precise moving tire contact patch distorted figure. Additionally, the rack bar axial force fluctuation factors of tire trajectory prescribed suspension layout is investigated.
