Method and apparatus for determining a value of a zero point offset of a yaw rate sensor

• US 8,649,936 B2
• Filed: 03/31/2008
• Issued: 02/11/2014
• Est. Priority Date: 03/30/2007
• Status: Expired due to Fees

• Current Assignee: Penny & Giles Controls Ltd. (Curtiss-Wright Corporation)
• Original Assignee: Penny & Giles Controls Ltd. (Curtiss-Wright Corporation)
• Inventors: Lewis, Jason
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): Do, Truc M
• Application Number:
  US12/450,560
• Publication Number:
  US 20110035097A1
• Time in Patent Office: 2,143 Days
• Field of Search: 701/1, 701/41, 701/71, 700/1, 700/5, 700/37, 700/38, 700/39, 700/67, 700/68, 700/69, 700/70, 700/71, 700/72, 700/89, 700/73, 702/85, 702/94, 702/95, 702/96, 702/104, 702/142, 324/765, 324/754, 324/758, 324/158.1, 303/146, 348/86
• US Class Current: 701/36
• CPC Class Codes: A61G 5/045 Rear wheel drive
• CPC Class Codes: B60L 3/0038 relating to sensors
• CPC Class Codes: G01C 19/42 for indicating rate of turn; for integrating rate of turn
• CPC Class Codes: G01C 25/00 Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass testing, calibrating or compensating compasses G01C17/38

Abstract

There is described a method for determining a value of a zero point offset of a yaw rate sensor. The method comprises measuring over time the output of the yaw rate sensor, determining whether the measured output has remained within a set of limits for a pre-determined period and if it is determined that the measured output has remained within the limits for the pre-determined period, using at least one measured value of the output to determine the value of the zero point offset.

Claims

1. A method of controlling operation of a vehicle comprising the steps of:

determining a value of a zero point offset of a yaw rate sensor by;

measuring over a pre-determined period of time an output of the yaw rate sensor,

determining whether the measured output has remained within a first set of limits and a second set of limits for the pre-determined period of time, and

using at least one measured value of the output to determine the value of the zero point offset when it is determined that the measured output has remained within the first set of limits and the second set of limits for the pre-determined period of time; and

preventing driving of the vehicle until the zero point offset has been determined.

2. A method according to claim 1, the method further comprising, using a timer or counter to determine whether the pre-determined period has been reached.

3. A method according to claim 1, wherein the step of using at least one measured value of the output to determine the value of the zero point offset comprises, calculating an average value of a plurality of measured values of the output and using the average value as the value of the zero point offset.

4. A method according to claim 1, wherein the first set of limits is determined in dependence upon at least one measured value of the output of the yaw rate sensor.

5. A method according to claim 4, wherein the first set of limits comprises an upper limit and a lower limit, the upper limit being set a predetermined amount higher than a value determined in dependence upon the at least one measured value and the lower limit being set at a pre-determined amount lower than the value determined in dependence upon the at least one measured value.

6. A method according to claim 4, wherein the first set of limits comprises an upper limit and a lower limit, the upper limit being set a predetermined amount higher than the at least one measured value and the lower limit being set at a pre-determined amount lower than the at least one measured value.

7. A method according to claim 4, wherein the first set of limits comprises an upper limit and a lower limit the values of which vary over the pre-determined period in dependence upon variations in the measured output.

8. A method according to claim 7, wherein the values of the upper and lower limits of the first set of limits vary over the pre-determined period in dependence upon a monitored average value of the measured output.

9. A method according to claim 8, wherein the values of the upper and lower limits of the first set of limits are respectively maintained a pre-determined amount above and below the monitored average value of the measured output.

10. A method according to claim 1, wherein the step of determining whether the measured output has remained within the first set of limits for the pre-determined period comprises obtaining a sequence of values of the measured output and for each value in the sequence, determining whether it is within the limits, prior to the next value in the sequence being obtained.

11. A method according to claim 7 wherein the step of determining whether the measured output has remained within the first set of limits for the pre-determined period comprises obtaining a sequence of values of the measured output and for each value in the sequence, determining whether current maximum and minimum values of the sequence are within current determined values of the limits, prior to the next value in the sequence being obtained.

12. A method according to claim 1, wherein the second set of limits have pre-determined upper and lower values that are independent of the measured output.

13. A method according to claim 12 wherein the pre-determined upper and lower values of the second set of limits are recommended permissible upper and lower values for the zero point offset of the sensor.

14. A method according to claim 1, wherein the method is ended and then started afresh if it is determined that the measured output is outside the first set of limits or the second set of limits.

15. A method according to claim 1, wherein the method is implemented by a vehicle control system which prevents the vehicle from being drivable until the value of the zero point offset is determined.

16. A vehicle control system for determining a value of a zero point offset of a yaw rate sensor, the system arranged to measure over time an output of a yaw rate sensor, the system comprising:

a control module programmed to determine whether the measured output has remained within a first set of limits and a second set of limits for a pre-determined period of time and further programmed to use at least one measured value of the output to determine the value of the zero point offset when the control module determines that the measured output has remained within the first set of limits and the second set of limits for the pre-determined period of time.

17. A vehicle control system according to claim 16, wherein the first set of limits is determined in dependence upon at least one measured value of the output of the yaw rate sensor.

18. A vehicle control system according to claim 17, wherein the second set of limits have pre-determined upper and lower values that are independent of the measured output.

19. A vehicle comprising:

a vehicle control system according to claim 16.

20. A vehicle according to claim 19, wherein the vehicle control system is programmed to render the vehicle undrivable until the value of the zero point offset is determined.