System and method for determining vehicle speed

• US 8,983,678 B2
• Filed: 09/22/2010
• Issued: 03/17/2015
• Est. Priority Date: 06/16/2010
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Louie, Justin, Tao, Xuefeng Tim
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): Figueroa, Jaime
• Application Number:
  US12/887,743
• Publication Number:
  US 20110313629A1
• Time in Patent Office: 1,637 Days
• Field of Search: 701/1, 701/51, 701/55, 731/150.8, 180/170, 303/121, 303/166, 303/168, 303/177, 303/183, 303/184, 303/185, 340/441, 702/142
• US Class Current: 701/1
• CPC Class Codes: G01P 11/00 Measuring average value of speed by determining time taken to traverse a fixed distance G01P3/64, G01P5/18
• CPC Class Codes: G01P 3/50 for measuring linear speed G01P3/56 takes precedence

Abstract

A system for a vehicle includes a speed determination module, a buffer module, and a speed prediction module. The speed determination module determines changes in measured vehicle speed. The buffer module stores the determined changes in measured vehicle speed. The speed prediction module predicts a speed of the vehicle when the measured vehicle speed is less than a predetermined threshold, wherein the predicted vehicle speed is based on an average of the stored changes in measured vehicle speed.

Claims

1. A system for a vehicle, comprising:

a speed determination module that determines changes in measured vehicle speed;

a buffer module that stores the determined changes in measured vehicle speed; and

a speed prediction module that predicts a speed of the vehicle when the measured vehicle speed is less than a predetermined threshold, wherein the predicted vehicle speed is based on an average of the stored changes in measured vehicle speed.

5. The system of claim 1, further comprising:

an inflection point detection module that detects a vehicle speed inflection point when a polarity of the changes in measured vehicle speed has changed for longer than a predetermined period.

9. The system of claim 1, further comprising:

a component control module that controls shifting of a transmission based on the predicted vehicle speed.

10. The system of claim 1, wherein the measured vehicle speed is based on measurements from one of a transmission output shaft speed (TOSS) sensor and an anti-lock braking system (ABS) wheel sensor.

2. A system for a vehicle, comprising:

a speed determination module that determines changes in measured vehicle speed;

a buffer module that stores the determined changes in measured vehicle speed;

a speed prediction module that predicts a speed of the vehicle when the measured vehicle speed is less than a predetermined threshold, wherein the predicted vehicle speed is based on an average of the stored changes in measured vehicle speed; and

a reset module that resets the buffer module when the buffer module includes greater than Y stored changes having less than a predetermined value, wherein Y is an integer greater than or equal to zero.

3. The system of claim 2, wherein the reset module resets the buffer module when the measured vehicle speed has been less than the predetermined threshold for longer than a predetermined period.

4. The system of claim 3, wherein either initially or after the buffer module is reset, the speed prediction module waits for N measured vehicle speeds greater than the predetermined threshold or for a predetermined period before predicting vehicle speed, wherein N is an integer greater than or equal to one.

6. A system for a vehicle, comprising:

a speed determination module that determines changes in measured vehicle speed;

a buffer module that stores the determined changes in measured vehicle speed;

a speed prediction module that predicts a speed of the vehicle when the measured vehicle speed is less than a predetermined threshold, wherein the predicted vehicle speed is based on an average of the stored changes in measured vehicle speed; and

an inflection point detection module that detects a vehicle speed inflection point when a polarity of the changes in measured vehicle speed has changed for longer than a predetermined period, wherein the inflection point detection module resets the buffer module when a vehicle speed inflection point is detected.

7. The system of claim 6, wherein after resetting the buffer module, the inflection point detection module loads the buffer module with an average of X changes in measured vehicle speed, wherein the X changes in measured vehicle speed correspond to a period after detecting the vehicle speed inflection point.

8. The system of claim 7, wherein after the buffer module is loaded, the speed prediction module resumes prediction of the vehicle speed.

11. A method for determining a speed of a vehicle, comprising:

determining changes in measured vehicle speed;

storing the determined changes in measured vehicle speed in a buffer; and

predicting the speed of the vehicle when the measured vehicle speed is less than a predetermined threshold, wherein the predicted vehicle speed is based on an average of the stored changes in measured vehicle speed.

15. The method of claim 11, further comprising detecting a vehicle speed inflection point when a polarity of the changes in measured vehicle speed has changed for longer than a predetermined period.

19. The method of claim 11, further comprising controlling shifting of a transmission based on the predicted vehicle speed.

20. The method of claim 11, further comprising measuring vehicle speed using one of a transmission output shaft speed (TOSS) sensor and an anti-lock braking system (ABS) wheel sensor.

12. A method for determining a speed of a vehicle, comprising:

determining changes in measured vehicle speed;

storing the determined changes in measured vehicle speed in a buffer;

predicting the speed of the vehicle when the measured vehicle speed is less than a predetermined threshold, wherein the predicted vehicle speed is based on an average of the stored changes in measured vehicle speed; and

resetting the buffer when the buffer includes greater than Y stored changes having less than a predetermined value, wherein Y is an integer greater than or equal to zero.

13. The method of claim 12, further comprising resetting the buffer when the measured vehicle speed has been less than the predetermined threshold for longer than a predetermined period.

14. The method of claim 13, further comprising either initially or after the buffer is reset, waiting for N measured vehicle speeds greater than the predetermined threshold or for a predetermined period before predicting vehicle speed, wherein N is an integer greater than or equal to one.

16. A method for determining a speed of a vehicle, comprising:

determining changes in measured vehicle speed;

storing the determined changes in measured vehicle speed in a buffer;

predicting the speed of the vehicle when the measured vehicle speed is less than a predetermined threshold, wherein the predicted vehicle speed is based on an average of the stored changes in measured vehicle speed;

detecting a vehicle speed inflection point when a polarity of the changes in measured vehicle speed has changed for longer than a predetermined period; and

resetting the buffer when a vehicle speed inflection point is detected.

17. The method of claim 16, further comprising after resetting the buffer, loading the buffer module with an average of X changes in measured vehicle speed, wherein the X changes in measured vehicle speed correspond to a period after detecting the vehicle speed inflection point.

18. The method of claim 17, further comprising after the buffer is loaded, resuming prediction of the vehicle speed.