Apparatus and method for the redundant, absolute position determination of a movable body
First Claim
1. An apparatus for contactlessly detecting the absolute position of an element which is movable relative to magnetosensitive sensors and has a magnetic field source fastened on the movable element, two magnetosensitive sensors which are in one plane and are spatially offset in the direction of movement being arranged at a distance from the magnetic field source in such a manner that a first sensor signal can be measured using the first magnetosensitive sensor and a second sensor signal can be measured using the second magnetosensitive sensor, the first sensor signal and the second sensor signal representing a component of the magnetic field and the sensor signals having a phase offset φ
- in the range of 0°
<
φ
<
180°
or 180°
<
φ
<
360°
,wherein the apparatus has a redundant design such that it has two sensor elements, two such magnetosensitive sensors being arranged in each sensor element, and the magnetosensitive sensors and the sensor elements being integrated together on a sensor chip,the apparatus further comprising evaluation electronics configured to calculate an absolute position of the magnetic field source using a normalized sum signal and a normalized difference signal, wherein the absolute position for the sensor signals from each sensor element is redundantly determined.
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Accused Products
Abstract
The invention relates to an apparatus for contactlessly detecting the absolute position of an element which can move relative to magnetosensitive sensors and has a magnetic field source fastened on the movable element, wherein two magnetosensitive sensors in a plane which are spatially offset in the direction of movement are arranged at a distance from the magnetic field source. Provision is made for the apparatus to be redundant such that said apparatus has two sensor elements, wherein two such magnetosensitive sensors are arranged in each sensor element.
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Citations
18 Claims
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1. An apparatus for contactlessly detecting the absolute position of an element which is movable relative to magnetosensitive sensors and has a magnetic field source fastened on the movable element, two magnetosensitive sensors which are in one plane and are spatially offset in the direction of movement being arranged at a distance from the magnetic field source in such a manner that a first sensor signal can be measured using the first magnetosensitive sensor and a second sensor signal can be measured using the second magnetosensitive sensor, the first sensor signal and the second sensor signal representing a component of the magnetic field and the sensor signals having a phase offset φ
- in the range of 0°
<
φ
<
180°
or 180°
<
φ
<
360°
,wherein the apparatus has a redundant design such that it has two sensor elements, two such magnetosensitive sensors being arranged in each sensor element, and the magnetosensitive sensors and the sensor elements being integrated together on a sensor chip, the apparatus further comprising evaluation electronics configured to calculate an absolute position of the magnetic field source using a normalized sum signal and a normalized difference signal, wherein the absolute position for the sensor signals from each sensor element is redundantly determined. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- in the range of 0°
-
13. A method for determining the absolute position of an element which is movable relative to magnetosensitive sensors using an apparatus for contactlessly detecting an element which is movable relatively and has a magnetic field source fastened on the movable element, a first sensor element and a second sensor element being arranged at a distance from the magnetic field source, two magnetosensitive sensors which are spatially offset in the direction of movement being arranged in each sensor element, provision being made for a first sensor signal to be measured using the first magnetosensitive sensor of each sensor element and for a second sensor signal to be measured using the second magnetosensitive sensor of each sensor element, the first sensor signal and the second sensor signal representing a component of the magnetic field, and the sensor signals having a phase offset φ
- in the range of 0°
<
φ
<
180°
or 180°
<
φ
<
360°
, provision being madefor amplitude ratios to be determined by dividing a predefinable signal swing by a difference between a maximum value and a minimum value of the respective sensor signals, for offset values around the respective zero point of the sensor signals to be determined from the minimum and maximum values of the sensor signals, for normalized sensor signals to be calculated by subtracting the offset values from the sensor signals and by means of normalization with the amplitude ratios, the minimum and maximum values being determined by means of a relative movement of the element and the magnetic field source fastened thereto over a complete movement path while simultaneously detecting the sensor signals from both sensors, for a sum signal and a difference signal to be formed from the normalized sensor signals, for the sum signal and the difference signal to in turn be normalized after determining the amplitude ratio, the minimum and maximum values being determined by means of a relative movement of the element and the magnetic field source fastened thereto over a complete movement path while simultaneously measuring the sum signal and the difference signal and evaluating the minimum and maximum values of the sum signal and of the difference signal, and for an absolute position of the magnetic field source to be calculated using the normalized sum signal and the normalized difference signal, wherein the absolute position for the sensor signals from each sensor element is redundantly determined. - View Dependent Claims (14, 15, 16, 17, 18)
- in the range of 0°
Specification