Vehicle attitude control apparatus

A vehicle attitude control apparatus that can individually control a drive power applied to right and left wheels including inside wheels and outside wheels so that when the vehicle is in an understeer condition, the drive power applied to the outside wheels is larger than the drive power applied to the inside wheels, and when the vehicle is in an oversteer condition, the drive power applied to the inside wheels is larger than the drive power applied to the outside wheels, said vehicle attitude control apparatus comprising:

• an operation member;
• a steering actuator that is driven in accordance with the operation of said operation member;
• means for transmitting the movement of said steering actuator to the wheels so that a steering angle changes in response to the movement of said steering actuator;
• a sensor to seek a behavior index value corresponding to a change in the movement of the vehicle that occurs based on the change in the steering angle;
• a sensor to seek an amount of operation of said operation member;
• means for seeking a target behavior index value corresponding to the sought amount of operation based on a stored relationship between said 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 a difference between the target behavior index value and the sought behavior index value based on a stored relationship between said difference and the steering angle correction value;
• and
• means for controlling said steering actuator so that the steering angle matches a target steering angle which is the sum of the steering angle set value and the steering angle correction value.

A vehicle attitude control apparatus that can individually control a braking force applied to right and left wheels including inside wheels and outside wheels such 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, said vehicle attitude control apparatus comprising:

• an operation member;
• a steering actuator that is driven in accordance with the operation of said operation member;
• means for transmitting the movement of said steering actuator to the wheels so that a steering angle changes in response to the movement of said steering actuator;
• a sensor to seek a behavior index value corresponding to a change in the movement of the vehicle that occurs based on the change in the steering angle;
• a sensor to seek an amount of operation of said operation member;
• means for seeking a target behavior index value corresponding to a sought amount of operation based on a stored relationship between said amount of operation and the target behavior index value;
• means for controlling said steering actuator so that the behavior index value matches the sought target behavior index value;
• means for seeking a wheel lateral slip angle;
• means for seeking, based on a stored equation, the braking force applied to the inside wheel that maximizes a vehicle yaw moment acting toward the inside of the turn, when the vehicle is determined to be in the understeer condition;
• and
• means for determining whether or not the size of a sought wheel lateral slip angle equals or exceeds a predetermined maximum value when it is determined that the vehicle is in the understeer condition, wherein:
• when the sought wheel lateral slip angle equals or exceeds said predetermined maximum value, braking force control is performed so that a sought braking force is applied, and the amount of control of the steering actuator to ensure that the behavior index value matches the target behavior index value is minimized, and
• when the sought wheel lateral slip angle is less than said predetermined maximum value, as the sought wheel lateral slip angle decreases, the amount of braking force control is reduced and the amount of control of the steering actuator to ensure that the behavior index value matches the target behavior index value is increased.