Real-time determination of grade and superelevation angles of roads

• US 20060276939A1
• Filed: 06/02/2005
• Published: 12/07/2006
• Est. Priority Date: 06/02/2005
• Status: Abandoned Application

• Current Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Ameen, Yashwant K.
• Application Number:
  US11/144,475
• Publication Number:
  US 20060276939A1
• Time in Patent Office: Days
• US Class Current: 701/1
• CPC Class Codes: B60T 2210/22 Banked curves
• CPC Class Codes: B60T 2210/24 Curve radius
• 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

Abstract

A novel method, apparatus, and system are disclosed for estimating a grade angle and superelevation angle of a road upon which a vehicle is traveling. In one embodiment, the present teachings comprise a method for measuring a quantity of specified vehicle associated parameters, including a grade angle composite acceleration parameter, which is used to derive an estimation of a grade angle. Similarly, a superelevation composite acceleration parameter is measured, and subsequently used to derive an estimation of a superelevation angle. Such grade angle and superelevation angle estimations are useful in certain vehicle safety applications.

Claims

1. A method for determining real-time parameters for a vehicle, comprising:

a) determining a grade angle component, comprising;

i) defining a vehicle first sensing axis that is approximately parallel to a longitudinal axis of the vehicle;

ii) defining a vehicle grade angle composite acceleration parameter, wherein the vehicle grade angle composite acceleration parameter comprises at least two grade angle components, including a gravity grade angle acceleration component and a grade angle vehicle acceleration component; and

iii) separating the gravity grade angle acceleration component from the grade angle vehicle acceleration component; and

b) determining a superelevation angle component, comprising;

i) defining a vehicle second sensing axis that is approximately parallel to a lateral axis of the vehicle;

ii) defining a vehicle superelevation composite acceleration parameter, wherein the vehicle superelevation composite acceleration parameter comprises at least two superelevation components, including a gravity superelevation component and a centrifugal acceleration component; and

iii) separating the gravity superelevation component from the centrifugal acceleration component.

2. The method of claim 1, wherein step of separating the gravity grade angle acceleration component from the grade angle vehicle acceleration component comprises:

a) measuring real-time vehicle velocity over a first predetermined time period;

b) measuring real-time vehicle accelerometer information over the first predetermined time period; and

c) calculating a grade angle incremental velocity residual.

3. The method of claim 1, wherein step of separating the gravitational superelevation component from the centrifugal acceleration component comprises:

a) measuring real-time vehicle velocity information over a second predetermined time period;

b) measuring a radius of curvature through which the vehicle is accelerating;

c) calculating a vehicle turn rate over the second predetermined time period;

d) calculating a vehicle centrifugal acceleration based at least in part on the radius of curvature measured in step (b), the real-time vehicle velocity information measured in step (a), and the vehicle turn rate calculated in step (c);

e) measuring a vehicle acceleration; and

f) calculating a superelevation incremental velocity residual.

4. The method of claim 2, wherein step (c) of calculating the grade angle incremental velocity residual comprises:

a) integrating the real-time vehicle accelerometer information incrementally and;

b) subtracting the real-time vehicle velocity from the incrementally integrated real-time vehicle acceleration information, thereby defining a grade angle incremental velocity residual.

5. The method of claim 3, wherein step (f) of calculating a superelevation incremental velocity residual comprises:

a) subtracting the vehicle centrifugal acceleration calculated in step (d) from the vehicle acceleration measured in step (e), thereby defining an acceleration component due to gravity; and

b) integrating the acceleration component due to gravity over the second predetermined time period thereby defining the superelevation incremental velocity residual.

6. The method of claim 3, wherein step (f) of calculating a superelevation incremental velocity residual comprises:

a) integrating the vehicle centrifugal acceleration over the second predetermined time period;

b) measuring a vehicle velocity; and

c) subtracting the integrated vehicle centrifugal acceleration of step (a) from the velocity measured in step (b), thereby defining a superelevation incremental velocity residual.

10. The apparatus of claim 7, further comprising:

a) a computer-readable medium capable of storing a computer program, wherein the computer program executes instructions implementing the method of claim 1.

13. The system of claim 1, further comprising:

a) a computer-readable medium capable of storing a computer program, wherein the computer program executes instructions implementing the method of claim 1.

7. An apparatus estimating real-time data associated with a vehicle, comprising:

a) a first accelerometer having a first sensing axis that is aligned approximately parallel to a longitudinal axis of a vehicle;

b) at least one electrical communication bus operatively coupled to the first accelerometer;

c) a digital signal processor operatively coupled to the at least one electrical communication bus;

d) a second accelerometer having a second sensing axis that is aligned approximately parallel to a lateral axis of the vehicle, wherein the second accelerometer is operatively connected to the at least one electrical communication bus; and

e) a yaw rate sensor operatively coupled to the at least one electrical communication bus.

8. The apparatus set forth in claim 7, wherein the at least one electrical communication bus comprises a wireless communication system.

9. The apparatus of claim 7, further comprising:

a) a digital computer system programmed to control operation of the apparatus set forth in claim 7.

11. A system simultaneously determining a grade angle and a superelevation angle of a vehicle, comprising:

a) a two-axis accelerometer having a first sensing axis and a second sensing axis, wherein the first sensing axis is approximately orthogonal to the second sensing axis, and wherein the first sensing axis is aligned approximately with a vehicle longitudinal vehicle axis, and wherein the second sensing axis is aligned approximately with a vehicle lateral vehicle axis;

b) an electrical communication bus operatively coupled to the two-axis accelerometer;

c) a yaw-rate sensor operatively coupled to the electrical communication bus; and

d) a digital signal processor operatively coupled to the electrical communication bus, wherein the digital signal processor calculates a grade angle and a superelevation estimate of a road upon which the vehicle is traveling.

12. The system of claim 11, further comprising:

a) a digital computer system programmed to control operation of the system defined in claim 11.

14. The system of claim 11, wherein the electrical communication bus comprises a wireless communication system.