Damper based vehicle yaw control
First Claim
1. A method for using controllable dampers to improve vehicle response and stability during severe handling maneuvers, the vehicle including at least one controllable damper, a front axle and a rear axle, the method comprising:
- a) responsive to vehicle dynamic variables, deriving a total handling damping value for the vehicle;
b) responsive to vehicle dynamic variables, deriving a control ratio of front axle roll damping to total roll damping for the vehicle;
c) responsive to the total handling damping value and the ratio of front axle roll damping to total roll damping, deriving a handling damping value for the controllable damper; and
d) blending the total handling damping value with a damping value derived from suspension component movement to determine a corner damping command for the controllable damper.
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Accused Products
Abstract
Controllable dampers are used to improve vehicle responses and stability during severe vehicle handling maneuvers. A total handling damping value for the vehicle is derived, preferably from the greatest of a yaw rate error value, a lateral acceleration value and a time derivative of lateral acceleration value. In addition, a control ratio of front axle roll damping to total roll damping is derived, preferably from the yaw rate error value, an oversteer/understeer indication and possibly vehicle speed. From these values, handling damping values are derived for each wheel of the vehicle and blended with damping values for the same wheels derived from suspension component movement to determine a corner damping command for each controllable damper. Preferably, the damping values derived from suspension component movement are shifted away from damping control of the vehicle body toward handling damping control when yaw rate error is large in magnitude.
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Citations
18 Claims
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1. A method for using controllable dampers to improve vehicle response and stability during severe handling maneuvers, the vehicle including at least one controllable damper, a front axle and a rear axle, the method comprising:
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a) responsive to vehicle dynamic variables, deriving a total handling damping value for the vehicle;
b) responsive to vehicle dynamic variables, deriving a control ratio of front axle roll damping to total roll damping for the vehicle;
c) responsive to the total handling damping value and the ratio of front axle roll damping to total roll damping, deriving a handling damping value for the controllable damper; and
d) blending the total handling damping value with a damping value derived from suspension component movement to determine a corner damping command for the controllable damper. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for using controllable dampers to improve vehicle responses and stability during severe handling maneuvers, the vehicle including at least one controllable damper, a front axle, a rear axle, the method comprising:
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a) measuring wheel speeds;
b) estimating vehicle speed c) measuring lateral acceleration;
d) measuring yaw rate;
e) measuring steering angle;
f) estimating slip angle and slip rate;
g) determining a desired yaw rate, a desired lateral acceleration, a desired slip angle, and a desired slip rate based upon a vehicle reference model;
h) determining an error term derived from the difference between the desired yaw rate, desired slip angle, and the desired slip rate and the measured yaw rate and estimated slip angle and slip rate;
i) determining if the vehicle is in an under steer or over steer condition and generating a steering signal flag;
j) determining a derivative of the desired lateral acceleration by multiplying the desired yaw rate by the vehicle speed then differentiating the product;
k) determining a handling pulse width modulation for each of the at least one controllable damper;
l) determining a handling scale factor;
m) blending the handling pulse-width modulation with a pulse width modulation derived from suspension component movement and having a wheel control component and a body control component multiplied by the handling scale factor to determine a total pulse width modulation for each of the controllable dampers.
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10. A method for improving vehicle responses and stability during severe maneuvers, the vehicle including a front axle with a pair of wheels having associated controllable dampers, a rear axle with a pair of wheels having associated controllable dampers, the method comprising:
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a) responsive to at least one of a yaw rate error between a desired yaw rate and a measured yaw rate of the vehicle, a lateral acceleration of the vehicle, and a time derivative of lateral acceleration of the vehicle, deriving a total handling damping value for the vehicle;
b) responsive to the yaw rate error between a desired yaw rate and a measured yaw rate of the vehicle, deriving a control ratio of axle roll damping on one of the front axle and the rear axle to total roll damping for the vehicle;
c) responsive to the total handling damping value and the control ratio, deriving a handling damping value for the controllable dampers associated with the wheels of one of the front axle and the rear axle; and
d) controlling the controllable dampers associated with the wheels of one of the front axle and the rear axle in response to their derived handling damping values. - View Dependent Claims (11)
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12. A method for using controllable dampers to improve vehicle response and stability during severe handling maneuvers, the vehicle including at least one controllable damper, a front axle and a rear axle, the method comprising:
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a) responsive to vehicle dynamic variables, deriving a total handling damping value for the vehicle;
b) responsive to vehicle dynamic variables, deriving a control ratio of front axle roll damping to total roll damping for the vehicle;
c) responsive to the total handling damping value and the ratio of front axle roll damping to total roll damping, deriving a handling damping value for the controllable damper; and
d) deriving a corner damping command for the controllable damper at least in part from the total handling damping value. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification