Apparatus and method for judging road surface gradients, and program for judging gradients

• US 6,738,704 B2
• Filed: 06/20/2002
• Issued: 05/18/2004
• Est. Priority Date: 06/22/2001
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: Kawasaki, Hiroaki
• Primary Examiner(s): Zanelli, Michael J.
• Application Number:
  US10/174,939
• Publication Number:
  US 20030033071A1
• Time in Patent Office: 698 Days
• Field of Search: 701/74, 701/80, 303/163, 303/191, 303/192
• US Class Current: 701/80
• CPC Class Codes: F16H 2059/405 Rate of change of output shaft speed or vehicle speed
• CPC Class Codes: F16H 2059/506 Wheel slip
• CPC Class Codes: F16H 2059/663 Road slope
• CPC Class Codes: F16H 59/48 Inputs being a function of acceleration
• CPC Class Codes: F16H 59/66 Road conditions, e.g. slope, slippery
• CPC Class Codes: G01C 9/00 Measuring inclination, e.g. by clinometers, by levels

Abstract

An apparatus for judging road surface gradients including a speed detector for periodically detecting wheel speeds of four wheels of a vehicle, a vehicle body speed calculator for obtaining a vehicle body speed of the vehicle, a slip rate calculator for obtaining a slip rate, a vehicle body acceleration calculator for obtaining an acceleration of the vehicle body of the vehicle, a determining device for determining whether the acceleration of the vehicle body is within a specified range proximate to zero, and a gradient judging device for judging a gradient of a road surface depending on the determination of the determining device. The gradients of road surfaces might be judged without using various sensors but only on the basis of information which can be obtained from a speed detector for detecting wheel speeds.

Claims

1. An apparatus for judging road surface gradients comprising:

a speed detecting means for periodically detecting wheel speeds of four wheels of a vehicle;

a vehicle body speed calculating means for obtaining a vehicle body speed of the vehicle;

a slip rate calculating means for obtaining a slip rate;

a means for calculating acceleration of the vehicle body for obtaining an acceleration of the vehicle body of the vehicle;

a determining means for determining whether the acceleration of the vehicle body is within a specified range; and

a gradient judging means for judging a gradient of a road surface depending on the determination of the determining means.

2. The apparatus of claim 1, wherein the gradient judging means judges a road surface gradient, in case the acceleration of the vehicle body is within a specified range which is proximate to zero, on the basis of values of slip rates which are within the specified range.

3. The apparatus of claim 1, wherein the gradient judging means performs linear regression of the slip rates and acceleration of the vehicle body to judge a road surface gradient by using values of slip rates obtained when the acceleration of the vehicle body is zero, in case the acceleration of the vehicle is not within a specified range which is proximate to zero within a specified period of time.

4. The apparatus of anyone of claims 2 to 3, wherein the obtained slip rate is corrected in accordance with the vehicle body speed of the vehicle.

5. The apparatus of claim 2, wherein the gradient judging means compares an average of the slip rates which are within the specified range with a slip rate which has been obtained when running on a flat road.

6. A method for judging road surface gradients comprising the steps of:

periodically detecting wheel speeds of four wheels of a vehicle;

obtaining a vehicle body speed of the vehicle;

obtaining a slip rate;

obtaining an acceleration of the vehicle body of the vehicle;

determining whether the acceleration of the vehicle body is within a specified range proximate to zero; and

judging a gradient of a road surface depending on the determination.

7. The method of claim 6, wherein a road surface gradient is judged, in case the acceleration of the vehicle body is within a specified range which is proximate to zero, on the basis of values of slip rates which are within the specified range.

8. The method of claim 6, wherein a road surface gradient is judged by performing linear regression of the slip rates and acceleration of the vehicle body to judge the road surface gradient by using values of slip rates obtained when the acceleration of the vehicle body is zero, in case the acceleration of the vehicle is not within a specified range which is proximate to zero within a specified period of time.

9. The method of any one of claims 7 to 8, wherein the obtained slip rate is corrected in accordance with the vehicle body speed of the vehicle.

10. The method of claim 7, wherein a road surface gradient is judged by comparing an average of the slip rates which are within the specified range with a slip rate which has been obtained when running on a flat road.

11. A computer-readable medium embodied with a program for judging gradients which makes a computer function as a vehicle body speed calculating means for obtaining a vehicle body speed of the vehicle, a slip rate calculating means for obtaining a slip rate, a means for calculating acceleration of the vehicle body for obtaining an acceleration of the vehicle body of the vehicle, a determining means for determining whether the acceleration of the vehicle body is within a specified range proximate to zero, and a gradient judging means for judging a gradient of a road surface depending on the determination of the determining means.

12. The computer-readable medium of claim 11, wherein the gradient judging means judges a road surface gradient, in case the acceleration of the vehicle body is within a specified range which is proximate to zero, on the basis of values of slip rates which are within the specified range.

13. The computer-readable medium of claim 11, wherein the gradient judging means performs linear regression of the slip rates and acceleration of the vehicle body to judge a road surface gradient by using values of slip rates obtained when the acceleration of the vehicle body is zero, in case the acceleration of the vehicle is not within a specified range which is proximate to zero within a specified period of time.

14. The computer-readable medium of any one of claims 12 to 13, wherein the obtained slip rate is corrected in accordance with the vehicle body speed of the vehicle.

15. The computer readable medium of claim 12, wherein the gradient judging means compares an average of the slip rates which are within the specified range with a slip rate which has been obtained when running on a flat road.