Road surface detecting device
First Claim
1. A road surface detecting device comprising:
- means for detecting instantaneous speeds of a wheel at regular intervals;
means for calculating a presumed speed of a vehicle from said instantaneous speeds;
means for calculating absolute values of differences between the subsequent instantaneous speeds of said wheel and said presumed speed of said vehicle; and
means for comparing said absolute values of said differences with a predetermined value and generating a bad road signal indicating that said vehicle is running on a rough road when said absolute values of said differences are not less than said predetermined value.
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Accused Products
Abstract
A road surface detecting device has a circular plate connected with an axle of a vehicle so as to be rotated with said axle, and has a large number of teeth at regular intervals in its outer periphery. A rotary sensor detecting the passage of the teeth of the circular plate, and generates a pulse signal, and a microcomputer receive the pulse signal. The microcomputer calculates instantaneous speeds of a wheel from the period of the pulse signal and calculates an average value of a plurality of instantaneous speeds obtained in the predetermined rotations of a wheel another average value of a plurality of instantaneous speeds obtained in the next predetermined rotations of a wheel is also calculated as a presumed speed of a vehicle based on one and another average values. The microcomputer then calculates an absolute value of a difference between the instantaneous speeds in the predetermined rotations after next of a wheel and the presumed speed of vehicle, cancels an absolute value of an oldest difference every time when an absolute value of a newest difference is obtained, and calculates a successive integrated value by adding absolute values of a predetermined number of differences to one another. The microcomputer determines the road surface condition to be a bad condition when the successive integrated value is not less than a predetermined value or as a good condition when the successive integrated value is not more than the predetermined value.
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Citations
14 Claims
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1. A road surface detecting device comprising:
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means for detecting instantaneous speeds of a wheel at regular intervals; means for calculating a presumed speed of a vehicle from said instantaneous speeds; means for calculating absolute values of differences between the subsequent instantaneous speeds of said wheel and said presumed speed of said vehicle; and means for comparing said absolute values of said differences with a predetermined value and generating a bad road signal indicating that said vehicle is running on a rough road when said absolute values of said differences are not less than said predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A road surface detecting device for a vehicle, comprising:
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means for detecting instantaneous speeds of a wheel at regular intervals; means for calculating a presumed speed of a vehicle from said instantaneous speeds; means for calculating absolute values of differences between the subsequent instantaneous speeds of said wheel and said presumed speed of said vehicle; and means for statistically processing said absolute values of said differences to obtain a statistical value and determining a road surface condition to be a bad condition when said statistical value is not less than a predetermined value, and to be a condition when said statistical value is not more than the predetermined value. - View Dependent Claims (9, 10, 11)
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12. A road surface detecting device for a vehicle having a wheel, comprising:
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sensor means, adapted to be mounted on the wheel of said vehicle, for generating a wheel signal indicative of a revolution of the wheel; means for calculating instantaneous wheel speeds based on said wheel signal; means for calculating a presumed speed of said vehicle by averaging said instantaneous wheel speeds during a predetermined period of time; means for generating an absolute difference signal by comparing a subsequent instantaneous wheel speed with the presumed vehicle speed; and means for comparing said absolute difference signal by comparing a subsequent instantaneous wheel spaced with the presumed vehicle speed; and means for comparing said absolute difference signal with a predetermined value and generating a bad road signal indicating that said vehicle is running on a rough road when said absolute difference signal is not less than a predetermined value.
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13. A road surface detecting device for a vehicle having a wheel, comprising:
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sensor means adapted to be mounted on the wheel of said vehicle, for generating a wheel signal indicative of a revolution of the wheel; means for calculating instantaneous wheel speeds based on said wheel signal; means for calculating a presumed speed of a vehicle by averaging said instantaneous wheel speeds during a predetermined period of time; means for generating an absolute difference signal by comparing a subsequent instantaneous wheel speed with the presumed speed; means for integrating said absolute difference signal for a predetermined time to obtain an integrated value; and means for comparing said integrated value with a predetermined value and determining said road surface to be in a bad condition when said integrated value is not less than the predetermined value.
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14. A road surface detecting device for a vehicle, comprising:
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means for detecting instantaneous speeds of a wheel and generating instantaneous speed signals indicative thereof; means for calculating an average speed by averaging said instantaneous speeds of said wheel during a predetermined period of time; means for comparing a subsequent instantaneous speed with said average speed and generating an absolute difference speed signal indicative thereof; and means for comparing said absolute difference speed signal with a predetermined value and generating a bad road signal indicating that said vehicle is running on a rough road when said difference speed exceeds the predetermined value.
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Specification