Method for judging road surface condition and device thereof, and program for judging road surface condition
First Claim
1. A device for judging road surface condition comprising:
- a wheel speed-detecting means for periodically detecting wheel rotational speeds of four wheel tires of a vehicle;
a memory means for memorizing said wheel rotational speed of each tires;
a slip ratio-calculating means for determining a slip ratio from said wheel rotational speeds;
an acceleration deceleration-calculating means for determining acceleration or deceleration of said vehicle;
a relation equation-calculating means for determining a relation equation between said slip ratio and said acceleration of said vehicle;
a judgment value-calculating means for determining a judgment value for judging a friction coefficient between road surface and tires based on slope of said relation equation determined; and
a threshold-setting means for setting a threshold used for judging friction coefficient from said judgment value with information of wireless tags buried in said tires.
1 Assignment
0 Petitions
Accused Products
Abstract
A judgment method of road surface condition includes steps of: periodically detecting the wheel rotational speeds of the four wheel tires of a vehicle, memorizing the wheel rotational speed of each of tires, determining a slip ratio from said wheel rotational speeds, determining the acceleration or deceleration of the vehicle, determining a relation equation between said slip ratio and the acceleration or deceleration of the vehicle, determining a judgment value for judging a friction coefficient between the road surface and tires based on the slope of said relation equation determined, and setting a threshold which is used for judging the friction coefficient from the judgment value using the information of wireless tags which were buried in the tires.
6 Citations
6 Claims
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1. A device for judging road surface condition comprising:
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a wheel speed-detecting means for periodically detecting wheel rotational speeds of four wheel tires of a vehicle; a memory means for memorizing said wheel rotational speed of each tires; a slip ratio-calculating means for determining a slip ratio from said wheel rotational speeds; an acceleration deceleration-calculating means for determining acceleration or deceleration of said vehicle; a relation equation-calculating means for determining a relation equation between said slip ratio and said acceleration of said vehicle; a judgment value-calculating means for determining a judgment value for judging a friction coefficient between road surface and tires based on slope of said relation equation determined; and a threshold-setting means for setting a threshold used for judging friction coefficient from said judgment value with information of wireless tags buried in said tires. - View Dependent Claims (2, 4)
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3. A program, provided in machine-readable memory of a control unit, for judging road surface condition, the program, when executed, causing the control unit to function as:
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a memory means for memorizing wheel rotational speed of each tires mounted on a vehicle; a slip ratio-calculating means for determining a slip ratio from said wheel rotational speeds; an acceleration deceleration-calculating means for determining acceleration or deceleration of said vehicle; a relation equation-calculating means for determining a relation equation between said slip ratio and said acceleration of the vehicle; a judgment value-calculating means for determining a judgment value for judging a friction coefficient between road surface and said tires based on slope of said relation equation determined; and a threshold-setting means for setting a threshold used for judging friction coefficient from said judgment value with information of wireless tags buried in said tires. - View Dependent Claims (5, 6)
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Specification