Redundant position sensing system for a vehicle

• US 20060190142A1
• Filed: 02/18/2005
• Published: 08/24/2006
• Est. Priority Date: 02/18/2005
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Katrak, Kerfegar K., Stockbridge, John N.
• Granted Patent: US 8,538,622 B2
• Time in Patent Office: Days
• US Class Current: 701/1
• CPC Class Codes: F02D 11/106 Detection of demand or actuation
• CPC Class Codes: F02D 11/107 Safety-related aspects
• CPC Class Codes: F02D 2400/08 Redundant elements, e.g. two sensors for measuring the same parameter
• CPC Class Codes: F02D 41/222 relating to the failure of sensors or parameter detection devices
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A redundant position sensing system includes a device having a position between minimum and maximum positions. First and second sensor modules include first and second sensor resistances. A value of one of the first or second sensor resistances increases and a value of the other of the first or second resistances decreases when the device moves from the minimum position to the maximum position. A maximum value of the first sensor resistance ranges between a first maximum value and a second maximum value that is greater than the first maximum value due to a first manufacturing tolerance. A maximum value of the second sensor resistance ranges between a third maximum value and a fourth maximum value that is greater than the third maximum value due to a second manufacturing tolerance. The second maximum value is less than the third maximum value.

Claims

1. A redundant position sensing system, comprising:

a device having a position between minimum and maximum positions; and

first and second sensor modules that include first and second sensor resistances, respectively, wherein a value of one of said first or second sensor resistances increases and a value of the other of said first or second resistances decreases when said device moves from said minimum position to said maximum position;

wherein a maximum value of said first sensor resistance ranges between a first maximum value and a second maximum value that is greater than said first maximum value due to a first manufacturing tolerance, wherein a maximum value of said second sensor resistance ranges between a third maximum value and a fourth maximum value that is greater than said third maximum value due to a second manufacturing tolerance, and wherein said second maximum value is less than said third maximum value.

2. The redundant position sensing system of claim 1 further comprising a control module that communicates with said first and second sensor modules, wherein said first and second sensor modules generate first and second position values based on said first and second sensor resistances, respectively, and wherein said sensor module determines first and second positions of said device based on said first and second position values, respectively.

3. The redundant position sensing system of claim 2 further comprising first and second conductors having first ends that communicate with said first and second sensor modules, respectively, and second ends that communicate with said control module, wherein said first sensor module transmits said first position value on said first conductor and said second sensor module transmits said second position value on said second conductor.

4. The redundant position sensing system of claim 2 wherein said control module compares said first and second position values and activates an alarm indicator when a difference between said first and second position values is less than a predetermined value.

5. The redundant position sensing system of claim 2 wherein said control module compares said first and second positions of said device and activates an alarm indicator when a difference between said first and second positions is greater than a predetermined value.

6. The redundant position sensing system of claim 2 wherein said control module converts said first and second positions of said device into first and second normalized values, respectively, that represent a fraction of a range between said minimum and maximum positions of said device.

7. The redundant position sensing system of claim 6 wherein said control module compares said first and second normalized values and activates an alarm indicator when a difference between said first and second normalized values is greater than a predetermined value.

8. The redundant position sensing system of claim 2 wherein said control module utilizes only said first position value for system control during normal operations and when no alarm indicators are activated.

9. The redundant position sensing system of claim 1 wherein said first and second manufacturing tolerances are approximately equal to 20% and wherein a ratio of said first maximum value of said first sensor resistance to said third maximum value of said second sensor resistance is less than or equal to 0.5.

10. The redundant position sensing system of claim 1 wherein said first and second sensor resistances are generated by a resistive ink deposition process.

11. The redundant position sensing system of claim 1 wherein first ends of said first and second sensor resistances communicate with a supply potential and second ends of said first and second sensor resistances communicate with a ground potential.

12. The redundant position sensing system of claim 2 wherein said first and second sensor modules include first and second series resistances, respectively, first ends of said first and second series resistances communicate with adjustable ends of said first and second sensor resistances, and said first and second series resistances generate said first and second position values, respectively.

13. The redundant position sensing system of claim 12 wherein said first and second position values are based on a voltage that is applied to said first and second sensor resistances and based on first and second combined resistances, respectively, and wherein said first and second combined resistances include said first and second sensor resistances, said first and second series resistances, and first and second contact resistances that are generated at said adjustable ends of said first and second sensor resistances, respectively.

14. The redundant position sensing system of claim 12 wherein said first and second series resistances have manufacturing tolerances that are approximately equal to 20% and wherein a ratio of a value of said first series resistance to a value of said second series resistance is less than or equal to 0.5.

15. The redundant position sensing system of claim 1 wherein minimum values of said first and second sensor resistances are set greater than or equal to 7% of said first maximum value of said first sensor resistance and said third maximum value of said second sensor resistance, respectively.

16. The redundant position sensing system of claim 1 wherein said device is one of an accelerator pedal, a brake pedal, a clutch pedal, or a throttle blade of a vehicle.

17. A redundant position sensing system for a vehicle, comprising:

a vehicle device having a position between minimum and maximum positions, wherein said vehicle device is one of an accelerator pedal, a brake pedal, a clutch pedal, or a throttle blade of a vehicle; and

first and second sensor modules that include first and second sensor resistances, respectively, wherein a value of one of said first or second sensor resistances increases and a value of the other of said first or second resistances decreases when said device moves from said minimum position to said maximum position;

wherein a ratio of a maximum value of said first sensor resistance to a maximum value of said second sensor resistance is less than or equal to 0.5.

18. A method for operating a redundant position sensing system, comprising:

connecting first and second sensor modules to a device having a position between minimum and maximum positions, wherein said first and second sensor modules include first and second sensor resistances, respectively;

increasing a value of one of said first or second sensor resistances when said device moves from said minimum position to said maximum position; and

decreasing a value of the other of said first or second sensor resistances when said device moves from said minimum position to said maximum position,

wherein a maximum value of said first sensor resistance ranges between a first maximum value and a second maximum value that is greater than said first maximum value due to a first manufacturing tolerance, wherein a maximum value of said second sensor resistance ranges between a third maximum value and a fourth maximum value that is greater than said third maximum value due to a second manufacturing tolerance, and wherein said second maximum value is less than said third maximum value.

19. The method of claim 18 further comprising:

generating a first position value based on said first sensor resistance;

generating a second position value based on said second sensor resistance;

transmitting said first and second position values to a control module; and

determining first and second positions of said device at said control module based on said first and second position values, respectively.

20. The method of claim 19 further comprising:

transmitting said first position value to said control module on a first conductor; and

transmitting said second position value to said control module on a second conductor.

21. The method of claim 19 further comprising:

comparing said first and second position values; and

activating an alarm indicator when a difference between said first and second position values is less than a predetermined value.

22. The method of claim 19 further comprising:

comparing said first and second positions of said device; and

activating an alarm indicator when a difference between said first and second positions is greater than a predetermined value.

23. The method of claim 19 further comprising converting said first and second positions of said device into first and second normalized values, respectively, that represent a fraction of a range between said minimum and maximum positions of said device.

24. The method of claim 23 further comprising:

comparing said first and second normalized values; and

activating an alarm indicator when a difference between said first and second normalized values is greater than a predetermined value.

25. The method of claim 19 further comprising utilizing only said first position value for system control during normal operations and when no alarm indicators are activated.

26. The method of claim 18 wherein said first and second manufacturing tolerances are approximately equal to 20% and wherein a ratio of said first maximum value of said first sensor resistance to said third maximum value of said second sensor resistance is less than or equal to 0.5.

27. The method of claim 18 further comprising generating said first and second sensor resistances by a resistive ink deposition process.

28. The method of claim 18 wherein first ends of said first and second sensor resistances communicate with a supply potential and second ends of said first and second sensor resistances communicate with a ground potential.

29. The method of claim 19 wherein said first and second sensor modules include first and second series resistances, respectively, first ends of said first and second series resistances communicate with adjustable ends of said first and second sensor resistances, and said first and second series resistances generate said first and second position values, respectively.

30. The method of claim 29 wherein said first and second position values are based on a voltage that is applied to said first and second sensor resistances and based on first and second combined resistances, respectively, and wherein said first and second combined resistances include said first and second sensor resistances, said first and second series resistances, and first and second contact resistances that are generated at said adjustable ends of said first and second sensor resistances, respectively.

31. The method of claim 29 wherein said first and second series resistances have manufacturing tolerances that are approximately equal to 20% and wherein a ratio of a value of said first series resistance to a value of said second series resistance is less than or equal to 0.5.

32. The method of claim 18 wherein minimum values of said first and second sensor resistances are set greater than or equal to 7% of said first maximum value of said first sensor resistance and said third maximum value of said second sensor resistance, respectively.

33. The method of claim 18 wherein said device is one of an accelerator pedal, a brake pedal, a clutch pedal, or a throttle blade of a vehicle.

34. A method for operating a redundant position sensing system for a vehicle, comprising:

connecting first and second sensor modules to a vehicle device having a position between minimum and maximum positions, wherein said first and second sensor modules include first and second sensor resistances, respectively, and wherein said vehicle device is one of an accelerator pedal, a brake pedal, a clutch pedal, or a throttle blade of a vehicle;

increasing a value of one of said first or second sensor resistances when said device moves from said minimum position to said maximum position; and

decreasing a value of the other of said first or second sensor resistances when said device moves from said minimum position to said maximum position,

wherein a ratio of a maximum value of said first sensor resistance to a maximum value of said second sensor resistance is less than or equal to 0.5.