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

• US 20030033071A1
• Filed: 06/20/2002
• Published: 02/13/2003
• Est. Priority Date: 06/22/2001
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: Kawasaki, Hiroaki
• Granted Patent: US 6,738,704 B2
• Time in Patent Office: Days
• 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 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 proximate to zero, and a gradient judging means for judging a gradient of a road surface on the basis of the determination of the determining means. 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 detecting means 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 proximate to zero, and a gradient judging means for judging a gradient of a road surface on the basis of 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 5 liner 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 any one of claims 2 to 3, wherein the obtained slip rate is corrected in accordance with the vehicle body speed of the vehicle.

5. 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 on the basis of the determination.

6. The method of claim 5, wherein a road surface gradient is judged, in case the acceleration of the vehicle body is within a specified range which proximate to zero, on the basis of values of slip rates which are within the specified range.

7. The method of claim 5, 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

8. The method of any one of claims 6 to 7, wherein the obtained slip rate is corrected in accordance with the vehicle body speed of the vehicle.

9. 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 on the basis of the determination of the determining means.