Method of determining boost direction in a power steering system

摘要

A method of determining a direction of a power boost applied to a power cylinder of a variable effort power steering system includes measuring a pressure of a hydraulic fluid between a pump and a control valve. A first position of the hand wheel is detected and initialized when the pressure is within a pre-defined equilibrium pressure range. A second position of the hand wheel is detected in response to rotational movement of the hand wheel. The first position and the second position of the hand wheel are measured in cumulative degrees rotated left or right of a on-center orientation of the hand wheel. The second position is subtracted from the first position to obtain a differential value representing the direction of the power boost. A negative differential value represents a first direction and a positive differential value represents a second direction of the power boost.