Apparatus and method for the determination of a direction of an object

• US 20050258820A1
• Filed: 04/06/2005
• Published: 11/24/2005
• Est. Priority Date: 04/07/2004
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Forster, Bernhard
• Granted Patent: US 7,535,215 B2
• Time in Patent Office: Days
• US Class Current: 324/165
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06
• CPC Class Codes: G01D 5/147 influenced by the movement of a third element, the position of Hall device and the source of magnetic field being fixed in respect to each other
• CPC Class Codes: G01D 5/2451 Incremental encoders G01D5/2454 takes precedence
• CPC Class Codes: G01P 13/04 Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement
• CPC Class Codes: G01P 3/488 delivered by variable reluctance detectors

Abstract

An apparatus for the determination of a momentary relative direction of an indicator object depending on a magnetic field influenced or generated by the indicator object includes first means for sensing a course of a first magnetic field component of the magnetic field, second means for sensing a course of a second magnetic field component of the magnetic field, and means for evaluating the course of the first magnetic field component and the second magnetic field component in order to determine the momentary, relative direction of the indicator object, the first magnetic field component and the second magnetic field component being offset in angle with respect to each other.

Claims

1. An apparatus for the determination of a momentary relative direction of an indicator object depending on a magnetic field influenced or generated by the indicator object, comprising:

a first sensor for sensing a course of a first magnetic field component of the magnetic field;

a second sensor for sensing a course of a second magnetic field component of the magnetic field; and

an evaluator for evaluating the course of the first magnetic field component and the second magnetic field component in order to determine the momentary, relative direction of the indicator object, the first magnetic field component and the second magnetic field component being offset in angle with respect to each other.

2. The apparatus of claim 1, wherein the first magnetic field component and the second magnetic field component are substantially perpendicular to each other.

3. The apparatus of claim 1, wherein the first and second sensors are arranged substantially perpendicular to the relative direction of the indicator object and spaced at a given distance from the indicator object.

4. The apparatus of claim 2, wherein the first magnetic field component passes substantially parallel to the relative direction of the indicator object, and wherein the second magnetic field component passes substantially perpendicular to the relative direction of the indicator object.

5. The apparatus of claim 1, wherein the first and second sensors are arranged immediately adjacent to each other.

6. The apparatus of claim 5, wherein the first and second sensors are arranged next to each other or on top of each other with reference to the relative direction of the indicator object.

7. The apparatus of claim 1, wherein the indicator object is a gear, a gear rack, a pole wheel, or a pole bar.

8. The apparatus of claim 1, wherein the relative direction is the direction of movement or direction of rotation of the indicator object relative to the first and second sensors.

9. The apparatus of claim 1, wherein the relative velocity is the longitudinal velocity or rotation velocity of the indicator object relative to the first and second sensors.

10. The apparatus of claim 1, wherein the first sensor provides a first evaluation signal and the second sensor a second evaluation signal, wherein the evaluator is formed to determine a reversal point of one of the evaluation signals and the slope in the reversal point of the one evaluation signal, and to assert the momentary value or the sign of the respective other evaluation signal, with a direction of rotation of the indicator object each being fixedly associated with each momentary value of sign with reference to the reversal point.

11. The apparatus of claim 10, wherein the first and second evaluation signals are phase-shifted by 90°

with respect to each other.

12. The apparatus of claim 1, wherein the first and/or second sensors comprise a sensor element of a group of sensor elements, the group comprising elements from the group consisting of AMR, GMR, TMR, CMR elements (AMR=anisotropic magnetoresistance, GMR=giant magnetoresistance, TMR=tunnel magnetoresistance, CMR=colossal magnetoresistance), vertical Hall sensor elements, horizontal Hall sensor elements, magnetoresistor elements, magnetotranisator elements (MAGFETs), giant planar Hall-effect sensors, spin transistors, GMI (giant magnetic impedance) elements, or magnetodiodes.

13. The apparatus of claim 1, wherein the first sensor comprises a sensor element sensitive with reference to the first magnetic field component, and wherein the second sensor comprises a sensor element sensitive with reference to the second magnetic field component.

14. The apparatus of claim 1, wherein the first and/or second magnetic field sensors comprise a plurality of sensor elements.

15. The apparatus of claim 14, wherein the plurality of sensor elements is connected in a bridge circuit.

16. The apparatus of claim 1, wherein the first sensor comprises two sensor elements at a given distance and the second sensor two sensor elements at a given distance.

17. The apparatus of claim 16, wherein the two sensor elements of the first sensor are equal, and wherein the two sensor elements of the second sensor are equal.

18. The apparatus of claim 16, wherein the waveforms of the two sensor elements of the first sensor and the waveforms of the two sensor elements of the second sensor are processed further differentially.

19. The apparatus of claim 16, wherein the two sensor elements of the first sensor and the two sensor elements of the second sensor are each arranged at a pitch distance of the indicator object with respect to each other.

20. A method of determining a momentary, relative direction of an indicator object depending on a magnetic field influenced or generated by the indicator object, comprising the steps of:

sensing a course of a first magnetic field component;

sensing a course of a second magnetic field component; and

evaluating the course of the first magnetic field component and the second magnetic field component in order to determine the momentary, relative direction of the indicator object, the first magnetic field component and the second magnetic field component being offset in angle with respect to each other.

21. A computer program with a program code for performing, when the computer program is executed on a computer, the method of determining a momentary, relative direction of an indicator object depending on a magnetic field influenced or generated by the indicator object, comprising the steps of:

sensing a course of a first magnetic field component;

sensing a course of a second magnetic field component; and

evaluating the course of the first magnetic field component and the second magnetic field component in order to determine the momentary, relative direction of the indicator object, the first magnetic field component and the second magnetic field component being offset in angle with respect to each other.