Patent ID: 6808041
Filing Date: 2004-10-26
Classification: B60T,B62D

Abstract:
A method for implementing directional control of a motor vehicle, the method comprising:determining whether a failure of a primary steering system of the motor vehicle exists; if a failure of the primary steering system exists, then creating a yaw moment on the vehicle by causing a differential longitudinal force to be applied with respect to a first wheel on one side of the vehicle and a second wheel on an opposite side of the vehicle, thereby causing the vehicle to turn in a commanded direction; wherein said causing a differential longitudinal force further comprises applying a braking force to at least one of said first and second wheels of the vehicle; wherein said creating a yaw moment on the vehicle further comprises: determining a desired directional response, determining whether a desired braking operation exists, and generating a brake torque output signal, based upon said desired directional response and whether said desired braking operation exists, said brake torque output signal being used in said selectively applying a braking force; wherein said desired directional response is determined by a closed-loop yaw rate control mechanism, said closed-loop yaw rate control mechanism being implemented by: generating an error signal, said error signal representing the difference between a desired yaw rate and said vehicle yaw rate; and said desired yaw rate being determined from a steering wheel angle and a vehicle speed; wherein said desired yaw rate is further determined by: inputting said steering wheel angle and said vehicle speed into a lookup table, said lookup table thereby determining a desired steady state yaw rate; and filtering said desired steady state yaw rate through a second order filter.