Road surface condition estimation method, and road surface condition estimation apparatus
First Claim
1. A method for estimating a road surface condition, comprising the steps of:
- detecting an unsprung fore-aft acceleration by an acceleration sensor attached to an unsprung position of a vehicle;
detecting a wheel speed;
calculating a variation in the detected wheel speed;
calculating a fluctuation range of the calculated variation in wheel speed and a fluctuation range of the detected unsprung fore-aft acceleration; and
estimating a road surface condition from a relationship between the fluctuation range of the variation in wheel speed and the fluctuation range of the unsprung fore-aft acceleration.
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Accused Products
Abstract
The invention provides a method and apparatus capable of accurately estimating a road surface condition under a traveling vehicle using unsprung acceleration and wheel speed data. The unsprung fore-aft acceleration (Gx) is detected by an acceleration sensor (11) attached to a knuckle (31) which is an unsprung component of a vehicle. At the same time, the wheel speed (Vw) is detected and the variation (ΔVw) in wheel speed is calculated. Then the fluctuation range (σ(ΔVw)) of the variation in wheel speed and the fluctuation range (σ(Gx)) of the unsprung fore-aft acceleration are calculated. And whether the road surface is a rough road surface with some bumpiness or a flat (smooth) road surface is estimated from a relationship between the fluctuation range (σ(ΔVw)) of the variation in wheel speed and the fluctuation range (σ(Gx)) of the unsprung fore-aft acceleration.
5 Citations
11 Claims
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1. A method for estimating a road surface condition, comprising the steps of:
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detecting an unsprung fore-aft acceleration by an acceleration sensor attached to an unsprung position of a vehicle; detecting a wheel speed; calculating a variation in the detected wheel speed; calculating a fluctuation range of the calculated variation in wheel speed and a fluctuation range of the detected unsprung fore-aft acceleration; and estimating a road surface condition from a relationship between the fluctuation range of the variation in wheel speed and the fluctuation range of the unsprung fore-aft acceleration. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A road surface condition estimating apparatus comprising:
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an unsprung fore-aft acceleration detecting means disposed at an unsprung position of a vehicle to detect an unsprung fore-aft acceleration; a wheel speed detecting means for detecting a wheel speed; a wheel speed variation calculating means for calculating a variation in the detected wheel speed; a fluctuation range calculating means for calculating a fluctuation range of the variation in wheel speed and a fluctuation range of the unsprung fore-aft acceleration; a storage means for storing a fluctuation range criterion formula representing a predetermined relationship between the fluctuation range of variation in wheel speed and the fluctuation range of unsprung fore-aft acceleration; and a road surface condition estimating means for estimating a road surface condition under a traveling vehicle, using the calculated fluctuation range of the variation in wheel speed and fluctuation range of the unsprung fore-aft acceleration and the fluctuation range criterion formula. - View Dependent Claims (9, 10, 11)
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Specification