Patent ID: 6470250
Filing Date: 2002-10-22
Classification: B60T,B62D

Abstract:
A vehicle attitude control apparatus, comprising:an operating member; a steering actuator driven in accordance with the operation of said operating member; a mechanism for transmitting movement of the steering actuator to the wheels of a vehicle, in such a manner that the steering angle changes in accordance with the movement thereof; means for determining a behaviour index value corresponding to changes in vehicle behaviour on the basis of changes in the steering angle; means for determining the amount of operation of said operating member; means for determining a target behaviour index value corresponding to the determined amount of operation, on the basis of a stored relationship between the amount of operation and the target behaviour index value; means for determining whether or not the vehicle is in a state of under-steer; means for controlling said steering actuator in such a manner that the behaviour index value follows the target behaviour index value, when the vehicle is not in the state of under-steer; means for controlling the braking forces at the vehicle wheels in such a manner that the behaviour index value follows the target behaviour index value, when the vehicle is not in the state of under-steer; means for determining an instability index value correlating to the degree of under-steer; means for storing a predetermined first relationship between the behaviour index value, the target behaviour index value, the instability index value and a corrected behaviour index value for steering; means for determining said corrected behaviour index value for steering on the basis of the determined behaviour index value, the determined target behaviour index value, the determined instability index value, and the stored first relationship; means for storing a predetermined second relationship between the behaviour index value, the target behaviour index value, the instability index value and a corrected behaviour index value for braking; and means for determining said corrected behaviour index value for braking on the basis of the determined behaviour index value, the determined target behaviour index value, the determined instability index value, and the stored second relationship; wherein the first relationship is determined in such a manner, as the magnitude of the instability index value increases up to a predetermined set value, the deviation between the target behaviour index value and the corrected behaviour index value for steering decreases, and when the target behaviour index value and the behaviour index value are equal, the corrected behaviour index value for steering becomes equal to the behaviour index value; the second relationship is determined in such a manner that as the magnitude of the instability index value increases up to a predetermined set value, the deviation between the target behaviour index value and the corrected behaviour index value for braking increases, and when the target behaviour index value and the behaviour index value are equal, the corrected behaviour index value for braking becomes equal to the behaviour index value; and when the vehicle is in the state of under-steer, said steering actuator is controlled in such a manner that said corrected behaviour index value for steering, instead of said behaviour index value, follows said target behaviour index value, and said braking forces are controlled in such a manner that said corrected behaviour index value for braking, instead of said behaviour index value, follows the target behaviour index value.