Method and apparatus for judging road surface conditions and program for judging road surface conditions

• US 20040098187A1
• Filed: 11/12/2003
• Published: 05/20/2004
• Est. Priority Date: 11/13/2002
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: Nakao, Yukio
• Granted Patent: US 7,389,170 B2
• Time in Patent Office: Days
• US Class Current: 701/80
• CPC Class Codes: B60T 2210/36 Global Positioning System [GPS]
• CPC Class Codes: B60T 2250/04 Vehicle reference speed; Vehicle body speed
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: B60W 2520/26 Wheel slip
• CPC Class Codes: B60W 2556/50 of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: B60W 40/064 Degree of grip

Abstract

A method for judging road surface conditions for judging road surface conditions on which a vehicle is running. The method includes the steps of: obtaining wheel speed rotational information of driving wheels of the vehicle during running from wheel speed detecting means, receiving GPS radio waves to calculate positional information, and judging road surface conditions during running on the basis of a relationship between the wheel speed rotational information and the positional information. Conditions of road surfaces on which a vehicle is running can be accurately judged.

Claims

1. A method for judging road surface conditions for judging road surface conditions on which a vehicle is running, comprising the steps of:

obtaining wheel speed rotational information of driving wheels of the vehicle during running from wheel speed detecting means, receiving GPS radio waves to calculate positional information, and judging road surface conditions during running on the basis of a relationship between the wheel speed rotational information and the positional information.

2. The method of claim 1, wherein the wheel speed rotational information is indicative of rotational velocities which are calculated upon reading periods of wheel speed pulses of the wheel speed detecting means and the number of pulses at specified time intervals;

the positional information is read in synchronization with time intervals of velocity detection for calculating rotational velocities to calculate a moving distance of the vehicle from the positional information;

the vehicle velocity and the acceleration of the vehicle are calculated from the moving distance; and

a slip rate is calculated from the rotational velocity and the vehicle velocity, and road surface conditions are judged during running by utilizing the relationship between slip rate and acceleration.

3. The method of claim 2, wherein moving averaging processes are performed for a specified number of values of the rotational velocity and the velocity or acceleration of the vehicle which have been read per each specified time interval.

4. An apparatus for judging road surface conditions for judging road surface conditions on which a vehicle is running, comprising:

wheel speed detecting means which detect wheel speed rotational information of tires of driving wheels of the vehicle, a GPS device which receives GPS radio waves and calculates positional information, and a road surface condition judging means which judges road surface conditions during running on the basis of a relationship between the wheel speed rotational information and the positional information.

5. The apparatus of claim 4, wherein the wheel speed rotational information is indicative of rotational velocities which are calculated upon reading periods of wheel speed pulses of the wheel speed detecting means and the number of pulses at specified time intervals;

the GPS device further includes a distance calculating means which reads the positional information in synchronization with time intervals of velocity detection for calculating rotational velocities and which calculates a moving distance of the vehicle from the positional information, and a vehicle information calculating means which calculates the vehicle velocity and the acceleration of the vehicle from the moving distance; and

the apparatus is further provided with a slip rate calculating means which calculates a slip rate from the rotational velocity and the vehicle velocity, and a judging means which judges road surface conditions during running on the basis of a relationship between the slip rate and the acceleration.

6. The apparatus of claim 5, wherein the apparatus further includes a moving average processing means which performs moving averaging processes for a specified number of values of the rotational velocity and the velocity or acceleration of the vehicle which have been read per each specified time interval.

7. A program for judging road surface conditions in which for judging road surface conditions, a computer is made to function as a road surface condition judging means which judges road surface conditions during running on the basis of a relationship between wheel speed rotational information of tires of driving wheels of the vehicle obtainable from wheel speed detecting means and positional information of the vehicle obtainable from a GPS device which receives GPS radio waves to calculate positional information.

8. The program of claim 7, wherein the wheel speed rotational information is indicative of rotational velocities which are calculated upon reading periods of wheel speed pulses of the wheel speed detecting means and the number of pulses at specified time intervals;

and the computer is further made to function as a slip rate calculating means which calculates a slip rate from the vehicle velocity calculated upon reading the positional information in synchronization with time intervals of velocity detection for calculating rotational velocities, and from the rotational velocity, and a judging means which judges road surface conditions during running on the basis of a relationship between the slip rate and acceleration calculated in the GPS device.

9. The program of claim 8, wherein the computer is yet further made to function as a moving average processing means which performs moving averaging processes for a specified number of values of the rotational velocity and the velocity or acceleration of the vehicle which have been read per each specified time interval.

10. A method for judging road surface conditions for judging road surface conditions on which a vehicle is running, comprising the steps of:

obtaining wheel speed rotational information of driving wheels of the vehicle during running from wheel speed detecting means, receiving GPS radio waves to calculate information on vehicle velocity, and judging road surface conditions during running on the basis of a relationship between the wheel speed rotational information and the information on vehicle velocity.

11. The method of claim 10, wherein the wheel speed rotational information is indicative of rotational velocities which are calculated upon reading periods of wheel speed pulses of the wheel speed detecting means and the number of pulses at specified time intervals;

the information on vehicle velocity is read in synchronization with time intervals of velocity detection for calculating rotational velocities;

the vehicle velocity and the acceleration of the vehicle are calculated from the information on vehicle velocity; and

a slip rate is calculated from the rotational velocity and the vehicle velocity, and road surface conditions are judged during running by utilizing the relationship between slip rate and acceleration.

12. The method of claim 11, wherein moving averaging processes are performed for a specified number of values of the rotational velocity and the velocity or acceleration of the vehicle which have been read per each specified time interval.

13. An apparatus for judging road surface conditions for judging road surface conditions on which a vehicle is running, comprising:

wheel speed detecting means which detect wheel speed rotational information of tires of driving wheels of the vehicle, a GPS device which receives GPS radio waves and calculates information on vehicle velocity, and a road surface condition judging means which judges road surface conditions during running on the basis of a relationship between the wheel speed rotational information and the information on vehicle velocity.

14. The apparatus of claim 13, wherein the wheel speed rotational information is indicative of rotational velocities which are calculated upon reading periods of wheel speed pulses of the wheel speed detecting means and the number of pulses at specified time intervals;

the GPS device further includes a vehicle information calculating means which reads the information on vehicle velocity in synchronization with time intervals of velocity detection for calculating rotational velocities and which calculates the vehicle velocity and the acceleration of the vehicle from the information on vehicle velocity; and

the apparatus is further provided with a slip rate calculating means which calculates a slip rate from the rotational velocity and the vehicle velocity, and a judging means which judges road surface conditions during running on the basis of a relationship between the slip rate and the acceleration.

15. The apparatus of claim 14, wherein the apparatus further includes a moving average processing means which performs moving averaging processes for a specified number of values of the rotational velocity and the velocity or acceleration of the vehicle which have been read per each specified time interval.

16. A program for judging road surface conditions in which for judging road surface conditions, a computer is made to function as a road surface condition judging means which judges road surface conditions during running on the basis of a relationship between wheel speed rotational information of tires of driving wheels of the vehicle obtainable from wheel speed detecting means and information on vehicle velocity obtainable from a GPS device which receives GPS radio waves.

17. The program of claim 16, wherein the wheel speed rotational information is indicative of rotational velocities which are calculated upon reading periods of wheel speed pulses of the wheel speed detecting means and the number of pulses at specified time intervals;

and the computer is further made to function as a slip rate calculating means which calculates a slip rate from the vehicle velocity calculated from information on vehicle velocity upon reading the information on vehicle velocity in synchronization with time intervals of velocity detection for calculating rotational velocities, and from the rotational velocity, and a judging means which judges road surface conditions during running on the basis of a relationship between the slip rate and acceleration calculated in the GPS device.

18. The program of claim 17, wherein the computer is yet further made to function as a moving average processing means which performs moving averaging processes for a specified number of values of the rotational velocity and the velocity or acceleration of the vehicle which have been read per each specified time interval.