Steering control apparatus for vehicle and steering control method

Abstract

A method for controlling a steering device with steering power support means for a motor vehicle with at least one steerable road wheel, where the steering device may include a steering shaft with a first end to adopt a steering wheel, a control device controlling said power support means, sensing means detecting steering shaft torque introduced in said steering shaft, and means to determine a hands-off situation in which the driver does not introduce a torque into said steering shaft, wherein the steering power support means support the driver on the basis of a driver demand introduced into the steering shaft, may comprise determining a steering wheel torque on basis of the steering shaft torque; determining a time derivative of the detected steering wheel torque; if the absolute value of the steering wheel torque is lower than a threshold torque limit and if the absolute value of the derivative of steering wheel torque is lower than a threshold derivative torque limit, a counter is increased by one count; if the absolute value of the steering wheel torque is higher or equal than a threshold torque limit, or/and if the absolute value of the derivative of steering wheel torque is higher or equal than a threshold derivative torque limit−, said counter is decreased by one count; and if said counter has a value equal to or higher than a threshold count limit the hands-off state is determined.

Dependencies are inferred from the claim text.