Electronic circuit for automatically compensating for errors in a sensor with an analog output signal

• US 5,757,181 A
• Filed: 06/07/1995
• Issued: 05/26/1998
• Est. Priority Date: 06/22/1992
• Status: Expired due to Term

• Current Assignee: Continental Automotive Systems, Inc. (Continental AG)
• Original Assignee: Durakool, Inc.
• Inventors: Nuss, John Richard, Wolf, Ronald J., Lynch, Martin James
• Primary Examiner(s): Snow, Walter E.
• Application Number:
  US08/486,650
• Time in Patent Office: 1,084 Days
• Field of Search: 324/207.12, 324/207.25, 324/207.21, 324/207.22, 324/225, 324/235, 324/173, 324/174
• US Class Current: 324/207.12
• CPC Class Codes: F02D 11/106 Detection of demand or actuation
• CPC Class Codes: F02D 41/2432 Methods of calibration
• CPC Class Codes: F02D 41/2474 Characteristics of sensors
• CPC Class Codes: G01D 3/02 with provision for altering or correcting the law of variation
• CPC Class Codes: G01D 3/022 having an ideal characteristic, map or correction data stored in a digital memory
• CPC Class Codes: G01D 3/0365 the undesired influence being measured using a separate sensor, which produces an influence related signal
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

A smart angular position sensor includes electronic circuitry for automatically compensating for errors in the output signal of the sensor. The electronic circuitry includes an electronic memory for storing predetermined compensation values used to compensate the output signal of the sensor. The predetermined compensation values are determined by comparing the output signal of the sensor with ideal values at predetermined angular positions. The deviation of the actual values relative to the ideal values is used in determining the compensation values. The compensation values are stored in the electronic memory and are used to automatically compensate the output signal of the sensor.

Claims

1. An electronic circuit for automatically compensating for part to part errors in a sensor which generates predetermined sensor output signals within a predetermined output range, the circuit comprising:

means for sensing the output signal of said sensor;

means for automatically compensating for non-temperature related part to part errors in said output signal, wherein said compensating means includes means for storing ideal output values for said sensor at predetermined calibration points and means for generating compensation values as a predetermined function of said ideal values for the entire output range of the sensor and wherein said compensating means further includes means for automatically compensating for errors in the output signal resulting from temperature deviations.

2. An electronic circuit as recited in claim 1, wherein said predetermined sensor output signals are analog signals.

3. An electronic circuit as recited in claim 1, wherein said predetermined sensor output signals are digital signals.

4. An angular position sensor for sensing the angular position of a pivotally mounted device mounted in a predetermined housing comprising:

a sensor housing adapted to be mechanically coupled to said predetermined housing;

a circular magnet with a central aperture for generating magnetic flux defining a magnetic axis through opposing North and South magnetic poles;

a drive arm, rotatably carried relative to said sensor housing, said drive arm including means for providing a mechanical coupling to said pivotally mounted device and means for carrying said magnet;

means at least partially disposed within said central aperture of said magnet for sensing the magnetic flux density generated by said magnet, said sensing means disposed at a substantially constant air gap relative to said magnet; and

means for enabling continuous mechanical adjustment of the sensitivity of said generating means.

5. An angular position sensor as recited in claim 4, further including means for providing temperature compensation for said sensor.

6. An angular position sensor as recited in claim 4, further including means for hermetically sealing said generating means.

7. An angular position sensor as recited in claim 6, wherein said sealing means includes a potting compound.

8. An angular position sensor as recited in claim 6, wherein said potting compound is an epoxy.

9. An angular position sensor as recited in claim 4, wherein said housing is formed from a predetermined non-magnetically conductive material.

10. An angular position sensor as recited in claim 9, wherein said predetermined material is plastic.

11. An angular position sensor for sensing the angular position of a pivotally mounted device mounted in a predetermined housing about a predetermined pivot axis, said sensor comprising:

a sensor housing adapted to be mechanically coupled to said predetermined housing, said housing including means for enabling rotatable coupling to said pivotally mounted device in said predetermined housing;

means for providing magnetic signals that vary as a function of the angular position of said pivotally mounted device including means for providing a mechanical coupling to said pivotally mounted device and a magnet having north and south magnetic poles defining one or more magnetic axes therethrough;

means responsive to said magnetic signals for generating electrical signals representative of said angular position of said pivotally mounted device, said generating means having a sensing plane for sensing said magnetic signals, said generating means having a predetermined offset voltage when said sensing plane is generally aligned with said magnetic axis;

said generating spaced away from said providing means defining a predetermined substantially constant air gap; and

sensitivity adjustment means for mechanically adjusting the sensitivity of said generating means.

12. An angular position sensor as recited in claim 11, wherein said magnet is a circular magnet.

13. An angular position sensor as recited in claim 11, further including means for linearizing the output signal of said generating means.

14. An angular position sensor for sensing the angular position of a pivotally mounted device about a predetermined pivot axis disposed in a predetermined housing, said sensor comprising:

a sensor housing adapted to be mechanically coupled to said predetermined housing and for enabling rotatable coupling with said pivotally mounted device;

means for providing magnetic signals that vary as a function of the angular position of said pivotally mounted device including a magnet having opposing north and south magnetic poles defining one or more magnetic axes therethrough, said providing means including means for providing a rotatable coupling to said pivotally mounted device in said predetermined housing; and

means responsive to said magnetic signals for generating electrical signals representative of the angular position of said pivotally mounted device, including a Hall effect device having a predetermined sensing plane, said sensing plane disposed substantially parallel with respect to said predetermined pivot axis.

15. An angular position sensor as recited in claim 14 further including means for linearizing the output signals from said generating means.

16. An angular position sensor for sensing the angular position of a pivotally mounted device about a predetermined pivot axis, said angular position sensor including a housing;

coupling means for providing a mechanical coupling to said pivotally mounted device, rotatably mounted relative to said housing;

magnetic field generating means having North and South poles; and

signal generating means responsive to said coupling means are generating an electrical signal representative of the angular position of said pivotally mounted device, characterized in that said magnetic field generating means consist of a circular magnet with a central aperture defining two semicircular portions of opposite magnetic polarities and that said signal generating means are disposed within said central aperture.

17. An electronic circuit for automatically compensating errors in the output signal of a displacement type sensor which generates predetermined sensor output signals within a predetermined output range, the errors due to part to part variations said sensor, said electronic circuit comprising:

a memory for storing ideal values for said output signals at predetermined points within said predetermined output range of said sensor;

means for compensating said output signals to compensate for part to part variations in said sensor relative to said stored ideal values and generating compensated output signals corresponding to said sensor output signals; and

means for compensating for errors due to temperature variations.

18. An electronic circuit as recited in claim 17, wherein said predetermined sensor output signals are analog signals.

19. An electronic circuit as recited in claim 17, wherein said predetermined sensor output signals are digital signals.