Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Indication or control of braking – acceleration – or deceleration
Reexamination Certificate
2001-02-06
2002-07-02
Cuchlinski, Jr., William A. (Department: 3663)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Indication or control of braking, acceleration, or deceleration
C701S001000, C701S036000, C701S072000, C701S042000, C701S008000, C701S220000, C701S207000, C701S041000, C701S096000, C701S084000, C701S074000, C303S140000, C303S146000, C303S148000, C303S147000, C180S197000, C180S167000, C180S445000, C180S168000, C180S443000, C180S400000, C340S436000, C340S435000, C340S465000
Reexamination Certificate
active
06415215
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a vehicle attitude control apparatus that can stabilize the movement of the vehicle.
DESCRIPTION OF THE RELATED ART
When a vehicle is in an understeer or oversteer condition, the vehicle's attitude is controlled through the control of the braking force or drive power applied to the vehicle. In other words, when the vehicle is in an understeer condition, the braking force applied to the wheels on the inside of the turn is made to exceed the braking force applied to the wheels on the outside of the turn, or the drive power applied to the outside wheels is made to exceed the drive power applied to the inside wheels. When a vehicle is in an oversteer condition, the braking force applied to the outside wheels is made to exceed the braking force applied to the inside wheels, or the drive power applied to the inside wheels is made to exceed the drive power applied to the outside wheels. In this way, a yaw moment that stabilizes the movement of the vehicle is generated.
In a vehicle in which the steering angle is changed in accordance with the movement of a steering actuator driven in response to the operation of a steering wheel, a target steering angle corresponding to the amount of operation of the steering wheel is sought, and the steering angle is subjected to feed forward control so that the actual steering angle will match the target steering angle.
Conventionally, this braking force control and steering angle control have been performed independently of each other. As a result, where the movement of the vehicle changes due to the application of braking force control, it has been necessary to subject the steering angle to feedback control so that behavior index value corresponding to the change in the movement of the vehicle, such as the yaw rate, matches the target behavior index value corresponding to the amount of operation of the steering wheel, such as the target yaw rate.
However, the problem arises that the stability of the vehicle's behavior is reduced due to the time lag between the change in the vehicle's behavior due to the application of braking control and the feeding back of the behavior index value corresponding to the change in the vehicle's behavior to the steering control.
Furthermore, the problem also arises that the yaw moment that stabilizes the movement of the vehicle declines, when the linear region in which the wheel lateral slip angle is proportional to the cornering force can no longer be maintained due to an excessive increase in the steering angle in order to eliminate the understeer condition, or when the braking force applied to the inner wheels becomes excessive.
Conventionally, when a vehicle is in an understeer condition, only the braking force applied to the inside rear wheel is increased, and the braking force applied to the inside front wheel is not increased. Furthermore, when a vehicle is in an oversteer condition, only the braking force applied to the outside front wheel is increased, and the braking force applied to the outside rear wheel is not increased. This is based on the fact that an increase in the braking force on the inside front wheel in an understeer situation or on the outside rear wheel in an oversteer situation is thought to have a negative impact on the stability of the vehicle's behavior. In other words, if the braking force on the inside front wheel is increased when the vehicle is in an understeer condition or the braking force on the outside rear wheel is increased when the vehicle is in an oversteer condition, the yaw moment that stabilizes the vehicle's behavior is thought to decline. However, conventional braking force control cannot sufficiently stabilize the vehicle's behavior, and further vehicle movement stabilization is desired.
An object of the present invention is to provide a vehicle attitude control apparatus that resolves the above problems.
SUMMARY OF THE INVENTION
A first aspect of the present invention comprises a vehicle attitude control apparatus that can individually control the braking force applied to the right and left wheels so that when the vehicle is in an understeer condition, the braking force applied to the inside wheels is larger than the braking force applied to the outside wheels, and when the vehicle is in an oversteer condition, the braking force applied to the outside wheels is larger than the braking force applied to the inside wheels, such apparatus includes an operation member, a steering actuator that is driven in accordance with the operation of the operation member, means for transmitting the movement of the steering actuator to the wheels so that the steering angle changes in response to this movement, means for seeking a behavior index value corresponding to the change in vehicle movement based on the change in the steering angle, means for seeking the amount of operation of the operation member, means for seeking a target behavior index value corresponding to the sought amount of operation of the operation member based on a stored relationship between the amount of operation and the target behavior index value, means for seeking the braking force applied to each wheel, means for seeking a braking force difference between the braking force applied to the inside wheels and the braking force applied to the outside wheels, means for calculating a steering angle set value corresponding to the sought target behavior index value and braking force difference based on a stored relationship between the target behavior index value, the braking force difference and the steering angle set value, means for calculating a steering angle correction value corresponding to the difference between the sought behavior index value and target behavior index value based on a stored relationship between this difference and the steering angle correction value, and means for controlling the steering actuator so that the steering angle matches the target steering angle which is the sum of the steering angle set value and the steering angle correction value.
A second aspect of the present invention comprises a vehicle attitude control apparatus that can individually control the drive power applied to the right and left wheels so that when the vehicle is in an understeer condition, the drive power applied to the inside wheels is larger than the drive power applied to the outside wheels, and when the vehicle is in an oversteer condition, the drive power applied to the outside wheels is larger than the drive power applied to the inside wheels, such apparatus includes an operation member, a steering actuator that is driven in accordance with the operation of the operation member, means for transmitting the movement of the steering actuator to the wheels so that the steering angle changes in response to this movement, means for seeking a behavior index value corresponding to the change in the movement of the vehicle that occurs based on the change in the steering angle, means for seeking the amount of operation of the operation member, means for seeking a target behavior index value corresponding to the sought amount of operation of the operation member based on a stored relationship between the amount of operation and the target behavior index value, means for seeking the drive power applied to each wheel, means for seeking a drive power difference between the drive power applied to the inside wheels and the drive power applied to the outside wheels, means for calculating a steering angle set value corresponding to the sought target behavior index value and drive power difference based on a stored relationship between the target behavior index value, the drive power difference and the steering angle set value, means for calculating a steering angle correction value corresponding to the difference between the sought behavior index value and the target behavior index value based on a stored relationship between this difference and the steering angle correction value, and means for controlling the steering actuator so that
Hayama Ryouhei
Nakano Shiro
Nishizaki Katsutoshi
Segawa Masaya
Cuchlinski Jr. William A.
Jordan and Hamburg LLP
Koyo Seiko Co. Ltd.
Mancho Ronnie
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