Method for road grade/vehicle pitch estimation
First Claim
1. A method of detecting a vehicle pitch angle for use in stability control system for a motor vehicle, said method comprising the steps of:
- generating a longitudinal speed signal corresponding to a longitudinal speed of the vehicle;
generating a longitudinal acceleration signal corresponding to a longitudinal acceleration of the vehicle;
generating a derivative signal corresponding to a derivative of said longitudinal speed;
generating a yaw rate signal corresponding to vehicle yaw rate;
generating a lateral velocity signal corresponding to the lateral velocity of the vehicle; and
determining said vehicle pitch angle in response to said derivative signal, said yaw rate signal and said lateral velocity signal.
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Accused Products
Abstract
A control system (13) for an automotive vehicle (10) includes a longitudinal accelerometer (24) that generates a longitudinal acceleration signal corresponding to a longitudinal acceleration of a center of gravity (COG) of the vehicle body. A lateral velocity sensor (22) generates a lateral velocity signal corresponding to the lateral velocity of the vehicle body. A controller (14) is coupled to the yaw rate sensor (18), the longitudinal accelerometer (24) and the lateral velocity sensor (22). The controller (14) determines a longitudinal speed from the longitudinal acceleration signal. The controller determines a vehicle pitch angle in response to the longitudinal speed, the yaw rate signal and the lateral velocity signal.
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Citations
20 Claims
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1. A method of detecting a vehicle pitch angle for use in stability control system for a motor vehicle, said method comprising the steps of:
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generating a longitudinal speed signal corresponding to a longitudinal speed of the vehicle;
generating a longitudinal acceleration signal corresponding to a longitudinal acceleration of the vehicle;
generating a derivative signal corresponding to a derivative of said longitudinal speed;
generating a yaw rate signal corresponding to vehicle yaw rate;
generating a lateral velocity signal corresponding to the lateral velocity of the vehicle; and
determining said vehicle pitch angle in response to said derivative signal, said yaw rate signal and said lateral velocity signal.
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2. A method as recited in claim 1 wherein said step of determining a vehicle pitch angle is performed in accordance with the equation
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3. A method as recited in claim 1 further comprising the step of controlling a safety device in response to said pitch angle.
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4. A method of detecting vehicle pitch angle as described in claim 1 further comprising:
determining a pitch estimation error in response to a pre-calibrated function in response to steering wheel angle, vehicle speed, said yaw rate and lateral acceleration.
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5. A method of detecting vehicle pitch angle as described in claim 4, wherein said step of determining said pitch estimation error comprises determining said pitch estimation error in response to the expression sinθ
- =(ay/g)·
(vn/u) where;u is the longitudinal speed and, ax is the longitudinal acceleration, vn is a lateral velocity estimation error; and
θ
is the vehicle pitch angle.
- =(ay/g)·
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6. A method of detecting vehicle pitch angle as recited in claim 5, wherein a pitch estimation bound is determined by the equation (ay/g)·
- (vn/u).
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7. A method of detecting a vehicle pitch angle as described in claim 5, further comprising determining an estimated lateral velocity in response to a lateral velocity observer.
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8. A method of detecting a vehicle pitch angle as described in claim 7, wherein said step of determining an estimated lateral velocity in response to a lateral velocity observer comprises determining the estimated lateral velocity in response to a vehicle speed, steering wheel angle, said yaw rate and a lateral acceleration.
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9. A method of detecting a vehicle pitch angle as described in claim 7, wherein said step of determining an estimated lateral velocity comprises determining a lateral velocity estimation error.
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10. A method of detecting a vehicle pitch angle as described in claim 1, further comprising calibrating said longitudinal acceleration signal, yaw rate signal, said lateral velocity signal.
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11. A method of detecting a vehicle pitch angle as described in claim 10, wherein said calibrating comprises during a steady state, generating an adjustment signal.
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12. A method of detecting a vehicle pitch angle as described in claim 11, wherein said step of generating an adjustment signal comprises deriving an adjustment signal in response to
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13. A method of pitch alignment for sensors of an automotive vehicle, said method comprising:
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generating a yaw rate signal corresponding to vehicle yaw rate;
generating a roll rate signal corresponding to vehicle roll rate;
generating a lateral acceleration signal corresponding to vehicle lateral acceleration;
determining when the vehicle is operating in a steady state turning condition;
generating a pitch angle alignment θ
when the vehicle is in the steady state turning condition where;
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14. A control system for an automotive vehicle having a vehicle body comprising:
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a yaw rate sensor generating a yaw motion signal corresponding to a yaw motion of the vehicle body;
a longitudinal accelerometer generating a longitudinal acceleration signal corresponding to a longitudinal acceleration of a center of gravity of the vehicle body;
a lateral velocity sensor generating a lateral velocity signal corresponding to the lateral velocity of the vehicle body; and
a controller coupled to said yaw rate sensor, said longitudinal accelerometer and said lateral velocity sensor, said controller determining a longitudinal speed from said longitudinal acceleration signal, said controller determining a vehicle pitch angle in response to said longitudinal speed, said yaw rate signal and said lateral velocity signal.
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15. A control system as recited in claim 14, further comprising a safety system coupled to said controller, said controller generating a control signal to said safety system in response to said vehicle pitch angle.
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16. A control system as recited in claim 15, wherein said safety system comprises an active brake control system.
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17. A control system as recited in claim 15, wherein said safety system comprises an active rear steering system.
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18. A control system as recited in claim 15, wherein said safety system comprises an active front steering system.
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19. A control system as recited in claim 15, wherein said safety system comprises an active anti-roll bar system.
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20. A control system as recited in claim 15, wherein said safety system comprises an active suspension system.
Specification