A method for controlling an electronic - hydraulic power steering system

摘要

A method is provided for controlling an electro-hydraulic power assist steering system including a variable-speed electric motor for pumping hydraulic fluid in the system. The method includes monitoring vehicle speed, vehicle steering wheel angle, and vehicle steering wheel turning rate. A parking mode or a driving mode is selected based upon the monitored vehicle speed. The speed of the variable speed electric motor is controlled based upon the monitored vehicle steering wheel turning rate if the parking mode is selected. If the driving mode is selected, the speed of the variable speed electric motor is controlled based upon the monitored vehicle speed, vehicle steering wheel angle and vehicle steering wheel angle turning rate. Accordingly, a wide range of vehicle driving conditions are accommodated and vehicle fuel efficiency is improved.