A power steering system for a vehicle includes a hydraulic system for
controlling resistance of a steering wheel. A valve of the hydraulic
system is connected to a coil which varies positioning of the valve. A
method for controlling the resistance of the steering wheel includes
turning the steerable wheels of the vehicle in response to rotation of
the steering wheel. The angle of the steering wheel and the speed of the
vehicle are sensed and inputted into a controller. A lateral acceleration
is determined based on the sensed signals by the controller. A
recommended current rate of the coil is determined based on the lateral
acceleration. An adjustment to the recommended current rate of the coil
is determined based upon the speed of the vehicle. The recommended
current rate is also modified based upon the adjustment. The modified
current rate of the coil is then applied to the coil to vary the
stiffness of the valve, which in turn varies the resistance to turning
the steerable wheels of the vehicle.