Method and system for determining condition of road
First Claim
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1. A method for determining the condition of a road travelled by an automotive vehicle, the method comprising:
- sensing a speed of the vehicle;
sensing a vertical acceleration of the vehicle;
determining a first road profile interval having upper and lower threshold values based on the speed of the vehicle; and
determining the condition of the road based on the vertical acceleration and the first road profile interval.
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Abstract
A method and system for determining the condition of a road travelled by a vehicle includes a sensor for sensing a speed of the vehicle and an accelerometer for sensing a vertical acceleration of the vehicle. A central processing unit have control logic programmed therein determines a first road profile interval having upper and lower threshold values based on the speed of the vehicle and determines the condition of the road based on the vertical acceleration and the first road profile interval.
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Citations
28 Claims
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1. A method for determining the condition of a road travelled by an automotive vehicle, the method comprising:
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sensing a speed of the vehicle;
sensing a vertical acceleration of the vehicle;
determining a first road profile interval having upper and lower threshold values based on the speed of the vehicle; and
determining the condition of the road based on the vertical acceleration and the first road profile interval. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
determining a mean vehicle speed; and
determining a maximum and minimum vertical acceleration value representative of a rough and smooth road, respectively, based on the mean vehicle speed.
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3. The method as recited in claim 2 wherein said step of determining the condition of the road comprises:
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determining a rough road condition if the sensed vertical acceleration exceeds the maximum vertical acceleration value; and
determining a smooth road condition if the sensed vertical acceleration is less than the minimum vertical acceleration value.
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4. The method as recited in claim 1 further comprising:
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determining a second road profile interval having upper and lower threshold values representative of the maximum and minimum vertical acceleration distributions corresponding to rough and smooth roads, respectively; and
determining the condition of the road based on the vertical acceleration and the second road profile interval if the vertical acceleration falls within the first road profile interval.
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5. The method as recited in claim 4 wherein said step of determining the condition of the road comprises:
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determining a standard deviation of the vertical acceleration;
determining a rough road condition if the standard deviation of the vertical acceleration exceeds the upper threshold value of the second road profile interval; and
determining a smooth road condition if the standard deviation of the vertical acceleration is less than the lower threshold value of the second road profile interval.
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6. The method as recited in claim 1 further comprising:
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determining a dynamic coefficient of friction corresponding to a minimum coefficient of friction required to achieve a particular change in vehicle speed;
comparing the dynamic coefficient of friction to a predetermined threshold; and
determining the vehicle is travelling at an excessive vehicle speed if the dynamic coefficient of friction is less than the predetermined threshold.
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7. The method as recited in claim 6 wherein said step of determining the dynamic coefficient of friction comprises:
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sensing a fore/aft acceleration of the vehicle; and
determining the dynamic coefficient of friction based on a current value of the fore/aft acceleration and a previous value of the fore/aft acceleration.
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8. The method as recited in claim 6 wherein said step of determining the dynamic coefficient of friction comprises:
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determining a distance traveled by a pair of wheels of the vehicle over a predetermined time interval; and
determining the dynamic coefficient of friction based on the distance traveled by the pair of wheels and the speed of the vehicle over the predetermined time interval.
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9. The method as recited in claim 6 further comprising displaying the dynamic coefficient of friction.
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10. The method as recited in claim 6 further comprising controlling the vehicle based on the dynamic coefficient of friction.
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11. The method as recited in claim 10 wherein said step of controlling the vehicle includes controlling a braking system of the vehicle.
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12. The method as recited in claim 1 further comprising controlling the vehicle based on the condition of the road.
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13. The method as recited in claim 12 wherein said step of controlling the vehicle includes controlling a suspension system of the vehicle.
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14. The method as recited in claim 12 wherein said step of controlling the vehicle includes controlling a braking system of the vehicle.
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15. A system for determining the condition of a road travelled by an automotive vehicle, the system comprising:
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a sensor for sensing a speed of the vehicle;
an accelerometer for sensing a vertical acceleration of the vehicle; and
a central processing unit, coupled to the sensor and the accelerometer, having control logic programmed therein for determining a first road profile interval having upper and lower threshold values based on the speed of the vehicle and determining the condition of the road based on the vertical acceleration and the first road profile interval. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification