Vehicle steering offset monitor

• US 5,795,997 A
• Filed: 08/01/1996
• Issued: 08/18/1998
• Est. Priority Date: 08/01/1996
• Status: Expired due to Fees

• Current Assignee: Arthur J. Gittins, Lawrence J. Wanner, Richard H. Adamson
• Original Assignee: Arthur J. Gittins, Lawrence J. Wanner, Richard H. Adamson
• Inventors: Adamson, Richard H., Gittins, Arthur J., Wanner, Lawrence J.
• Primary Examiner(s): Dombroske, George M.
• Application Number:
  US08/633,579
• Time in Patent Office: 747 Days
• Field of Search: 73/118.1, 340/438
• US Class Current: 73/117.02
• CPC Class Codes: B62D 15/02 Steering position indicators ; Steering position determination; Steering aids
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06
• CPC Class Codes: G01M 17/06 Steering behaviour; Rolling behaviour

Abstract

A apparatus and method for detecting an out-of-alignment condition of a wheeled vehicle with at least one steered wheel controlled by a steering wheel by comparing the relative number of periodic samples during a sampling period in which the vehicle steering wheel is positioned right of the center position as compared to left of the center position.

Claims

1. An apparatus for detecting an out-of-alignment condition of a wheeled vehicle with at least one steered wheel controlled by a steering wheel by comparing the relative number of periodic samples during a sampling period in which the vehicle steering wheel is positioned right of the center position as compared to left of the center position, the apparatus comprising;

sampler that periodically samples the position of the steering wheel and determines whether the steering wheel is in a center position, or a left position left of the center position, or a right position right of the center position,

fault determiner that determines a left fault condition when the number of samples in the left position exceeds the number of samples in the right position by a first predetermined number during the sampling period, or determines a right fault condition when the number of samples in the right position exceed the number of samples in the left position by the first predetermined number during the sampling period,

auto-reset that initiates a new sampling period when a left fault condition is determined, or a right fault condition is determined, or the number of samples made by the sampler during the sampling period reaches a second predetermined duration number,

a status indicator that indicates to a user a left failure or a right failure based upon a comparison of accumulated right fault conditions and accumulated left fault conditions over one or more sampling periods.

2. An apparatus as in claim 1 wherein the ratio of the first predetermined number to the second predetermined number is about 20%.

3. An apparatus as in claim 1 wherein the sampler comprises;

a stimulus attached to a rotatable together with a steering hub of the steering wheel

sensing system stationary with a column of the steering wheel such that the sensing system can determine a center position, left position, or a right position based upon the relative position of the stimulus with the sensing system.

4. An apparatus as in claim 3 additionally comprising a manual reset that initiates a new sampling period and resets the registers to initial values upon manual activation by the user.

5. An apparatus as in claim 3 wherein the stimulus comprises a magnetic material and the sensor comprises magnetic sensors.

6. An apparatus as in claim 1 wherein the fault determiner comprises a status register that is incremented when a sample is in the left position and decremented when a sample is the right position and a left fault condition is determined when the status register reaches a number that is equal to a initial value in the register plus the first predetermined value, and a right fault condition is determined when the status register reaches a number that is equal to the initial value in the status register minus the first predetermined value, and the auto-reset resets the status register to the initial value.

7. An apparatus as in claim 1 wherein the fault determiner comprises a status register that is decremented when a sample is in the left position and incremented when a sample is the right position and a left fault condition is determined when the status register reaches a number that is equal to a initial value in the register minus the first predetermined value, and a right fault condition is determined when the status register reaches a number that is equal to the initial value in the status register plus the first predetermined value, and the auto-reset resets the status register to the initial value.

8. An apparatus as in claim 1 wherein the status indicator indicates a left failure when the accumulated number of left fault conditions exceed the accumulated number of right fault conditions by a third predetermined number, and the status indicator indicates a right failure when the accumulated number of right fault conditions exceed the accumulated number of left fault conditions by the third predetermined number.

9. An apparatus as in claim 1 additionally comprising a system pauser that pauses the operation of the fault determiner upon ignition activation and resumes the operation of the fault determiner after a predetermined fourth number of center positions have been sampled by the sampler.

10. An apparatus as in claim 1 wherein the sample comprises a left position sensor and a right position sensor, the sampler determining a center position when both sensors are activated, determining a left position when the left sensor is activated and the right sensor is not activated, determining a right position when the right position is activated and the left sensor is not activated,

when both sensors are not activated the sampler determining a same position that was determined immediately before both sensors became not activated.

11. An apparatus as in claim 1 wherein the sampler periodically samples the position of the steering wheel at a constant preset time interval.

12. An apparatus as in claim 1 wherein the sampler periodically samples the position of the steering wheel at an interval based upon distance of vehicle travel.

13. A method for detecting an out-of-alignment condition of a wheeled vehicle with at least one steered wheel controlled by a steering wheel, the method comprising;

comparing the relative number of periodic samples during a sampling period in which the vehicle steering wheel is positioned right of the center position as compared to left of the center position.

14. A method for detecting an out-of-alignment condition of the wheeled vehicle with at least one steered wheel controlled by a steering wheel, the method comprising;

periodically sampling the position of the steering wheel and determining whether the steering wheel is in a center position, or a left position, of a right position) determining a left fault condition when the number of samples in the left position exceeds the number of samples in the right position by a first predetermined number during the sampling period,

determining a right fault condition when the number of samples in the right position exceed the number of samples in the left position by the first predetermined number during the sampling period,

resetting to initiate a new sampling period when a left fault condition is determined, or a right fault condition is determined, or the number of samples made by the sampler during the sampling period reaches a second predetermined duration number,

indicating to a user a left failure or a right failure based upon a comparison of accumulated right fault conditions and accumulated left conditions over one or more sampling periods.

15. A method as in claim 14 wherein the left fault condition is determined by incrementing a status register when a sample is in the left position and the status register reaches a number that is equal to a initial value in the register plus the first predetermined value, and a right fault condition is determined by decrementing the status register when a sample is in the right position and the status register reaches a number that is equal to the initial value in the status register minus the first predetermined value.

16. A method as in claim 14 wherein the left fault condition is determined by decrementing a status register when a sample is in the left position and the status register reaches a number that is equal to a initial value in the register minus the first predetermined value, and a right fault condition is determined by incrementing the status register when a sample is in the right position and the status register reaches a number that is equal to the initial value in the status register plus the first predetermined value.

17. A method as in claim 14 wherein a left failure is indicated when the accumulated number of left fault conditions exceed the accumulated number of right fault conditions by a third predetermined number, and a right failure when the accumulated number of right fault conditions exceed the accumulated number of left fault conditions by the third predetermined number.

18. A method as in claim 14 wherein the periodic sampling of the position of the steering wheel is at a constant preset time interval.

19. A method as in claim 14 wherein the periodic sampling of the position of the steering wheel is at an interval based upon distance of vehicle travel.

20. A method as in claim 14 wherein the periodic sampling of the position of the steering wheel may changed to a test mode wherein the sampling period is shorter.