Self aligning torque reference value calculating apparatus, method thereof, and road surface friction state estimating apparatus, method thereof
First Claim
1. A self aligning torque reference value calculating apparatus comprising:
- a self aligning torque estimating portion which estimates a self aligning torque applied to a tire;
a slip angle estimating portion which estimates a slip angle of the tire;
a self aligning torque model value calculating portion which calculates a self aligning torque model value using the slip angle estimated by the slip angle estimating portion;
a self aligning torque ratio calculating portion which calculates a self aligning torque ratio which is a ratio between the self aligning torque estimated by the self aligning torque estimating portion and the self aligning torque model value calculated by the self aligning torque model value calculating portion; and
a self aligning torque reference value calculating portion which calculates a self aligning torque reference value based on the self aligning torque ratio and the self aligning torque model value when a maximum value of the self aligning torque ratio calculated by the self aligning torque ratio calculating portion exceeds a threshold value.
1 Assignment
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Accused Products
Abstract
A SAT estimating portion obtains an estimated SAT value based on a sum of steering torque and assist torque. A SAT model value calculating portion calculates a SAT model value based on a slip angle. A SAT ratio calculating portion calculates a ratio between the estimated SAT value and the SAT model value. A SAT reference value calculating portion determines that a contact length between a tire and a road surface increases due to an increase in a load of a vehicle or a reduction in a tire pressure, and a SAT inclination increases, and obtains a SAT reference value by upwardly adjusting the SAT model value when a maximum value of the SAT ratio exceeds a threshold value in a predetermined time.
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Citations
9 Claims
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1. A self aligning torque reference value calculating apparatus comprising:
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a self aligning torque estimating portion which estimates a self aligning torque applied to a tire;
a slip angle estimating portion which estimates a slip angle of the tire;
a self aligning torque model value calculating portion which calculates a self aligning torque model value using the slip angle estimated by the slip angle estimating portion;
a self aligning torque ratio calculating portion which calculates a self aligning torque ratio which is a ratio between the self aligning torque estimated by the self aligning torque estimating portion and the self aligning torque model value calculated by the self aligning torque model value calculating portion; and
a self aligning torque reference value calculating portion which calculates a self aligning torque reference value based on the self aligning torque ratio and the self aligning torque model value when a maximum value of the self aligning torque ratio calculated by the self aligning torque ratio calculating portion exceeds a threshold value. - View Dependent Claims (2, 3, 4)
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5. A road surface friction state estimating apparatus comprising:
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a self aligning torque estimating portion which estimates a self aligning torque applied to a tire;
a slip angle estimating portion which estimates a slip angle of the tire;
a self aligning torque model value calculating portion which calculates a self aligning torque model value using the slip angle estimated by the slip angle estimating portion;
a self aligning torque ratio calculating portion which calculates a self aligning torque ratio which is a ratio between the self aligning torque estimated by the self aligning torque estimating portion and the self aligning torque model value calculated by the self aligning torque model value calculating portion;
a self aligning torque reference value calculating portion which calculates a self aligning torque reference value based on the self aligning torque ratio and the self aligning torque model value when a maximum value of the self aligning torque ratio calculated by the self aligning torque ratio calculating portion exceeds a threshold value; and
a road surface friction state estimating portion which estimates a road surface friction state based on the self aligning torque estimated by the self aligning torque estimating portion and the self aligning torque reference value calculated by the self aligning torque reference value calculating portion. - View Dependent Claims (6, 7)
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8. A self aligning torque reference value calculating method comprising the steps of:
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estimating self aligning torque applied to a tire;
estimating a slip angle of the tire;
calculating a self aligning torque model value using the estimated slip angle;
calculating a self aligning torque ratio which is a ratio between the estimated self aligning torque and the calculated self aligning torque model value; and
calculating a self aligning torque reference value based on the self aligning torque ratio and the self aligning torque model value when a maximum value of the calculated self aligning torque ratio exceeds a threshold value.
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9. A road surface friction state estimating method comprising:
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estimating a self aligning torque applied to a tire;
estimating a slip angle of the tire;
calculating a self aligning torque model value using the slip angle estimated;
calculating a self aligning torque ratio which is a ratio between the self aligning torque estimated and the self aligning torque model value calculated;
calculating a self aligning torque reference value based on the self aligning torque ratio and the self aligning torque model value when a maximum value of the self aligning torque ratio calculated exceeds a threshold value; and
estimating a road surface friction state based on the self aligning torque estimated and the self aligning torque reference value calculated.
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Specification