DE102008026604A1 - Position or speed sensor arrangement, particularly revolution speed sensor arrangement for use in motor vehicles, has sensor with sensitive principal plane and encoder with encoder groove surface - Google Patents

Abstract

The position or speed sensor arrangement has a sensor (1) with a sensitive principal plane (3) and an encoder (2) with an encoder groove surface (4). The sensor detects the magnetic field produced or modulated by the encoder. The sensor has two magnetic field sensor elements which are so arranged that an element output signal of the former magnetic field sensor element has a phase shift value between 75 degree and 105 degree to another element output signal of the latter magnetic field sensor element. An independent claim is included for a method for position or speed measurement with a sensor arrangement.

Description

The The invention relates to a position and / or speed sensor arrangement according to the preamble of claim 1, a method for position and / or speed measurement according to the preamble of claim 11 and the use of the sensor assembly in motor vehicles.

pamphlet DE 10 2005 039 280 A1 proposes an integrated sensor having a group of magnetic field sensor elements and a signal processing circuit. The group comprises magnetic field sensor elements with different main detection directions, for example both magnetoresistive sensor elements and Hall elements. The magnetic field sensor elements of the group are arranged in the form of a grid and detect a magnetic field spatially resolved, ie with respect to different detection points.

The Invention has set itself the task of a position and / or Speed sensor arrangement and a method for position and / or to suggest speed measurement, which only a relatively simple signal processing for obtaining position and / or speed information and in particular additional information needed.

The The object is achieved by the Sensoran Regulation according to claim 1 and the method according to claim 11.

Of the The invention is based on the idea, at least two magnetic field sensor elements to arrange with mutually different main detection direction, that the element output signals of these magnetic field sensor elements have a phase shift amount between 75 ° and 105 ° to each other.

Under a first sensitive main plane is preferably a plane understood, with respect to which the sensor is sensitive and Field components of the magnetic field can detect which this plane penetrate. The penetration angle of the field components, the can be detected in particular of the type and the arrangement of the magnetic field sensor elements dependent.

The Encoder track surface preferably has a scale for encoding or detecting rotary or alternatively translational Relative movements on.

The Magnetic field is preferably in the course of a relative movement between Encoder and sensor modulated by the encoder. It is in particular the sensor or encoder is stationary.

The Sensor arrangement is preferred over at least two lines connected to an electronic control unit and is in particular over these two lines supplied with energy. The sensor is the appropriately as an active sensor educated.

The first main detection direction of the first magnetic field sensor element is preferably in the first sensitive main plane of the sensor.

The The first sensitive main plane of the sensor is preferably a base surface a sensor housing or to this base area essentially parallel.

Of the Phase shift amount between the at least one element output signal the first magnetic field sensor element and the at least one element output signal of the second magnetic field sensor element is expediently in Essentially 90 °.

It it is preferred that the first and the second magnetic field sensor element are formed so that the first magnetic field sensor element substantially Magnetic field components detected in the other direction than the second Magnetic field sensor element. This results in particular from the first and second main detection direction corresponding to the respective magnetic field sensor element type assigned.

Of the Sensor is preferably sensitive to its first Main plane substantially parallel to the encoder track surface aligned with the encoder. Alternatively, preferably, sensor and Encoder arranged relative to each other so that the Angle between the first sensitive main plane of the sensor and the encoder track area is less than 15 °. By this arrangement, the sensor arrangement can be relatively flat or saves space and thus relatively inexpensive become.

The first and the second magnetic field sensor element preferably each have one or more sensitive structures which are each arranged substantially in a structural plane, wherein the first and the second magnetic field sensor element are arranged substantially parallel to each other or in a common plane with respect to their respective structural plane. Alternatively, preferably, the angle between the structural planes of the first and the second magnetic field sensor element is less than 15 °. Under a sensitive structure is particularly preferred a conductor segment of a magnetoresistive sensor element and / or a Hall cell or a segment of a Hall element understood.

The first main detection direction is expediently to the second main detection direction substantially 90 ° turned pronounced.

The first magnetic field sensor element with the first main detection direction is preferably designed as a magnetoresistive sensor element and the second magnetic field sensor element with the second main detection direction as a hall element. The at least one magnetoresistive sensor element is particularly known as AMR (anisotropic magnetoresistive) or GMR (giant magnetoresistive) sensor element or as another magnetoresistive Sensor element formed.

The Encoder track surface of the encoder is preferably alternating coded and in particular has several north-south pole pairs and / or tooth-gap pairs.

At least the first and the second magnetic field sensor elements are expediently arranged so that they have the magnetic field with respect to the first sensitive main plane of the sensor in a defined, common Essentially capture detection point together. Here are in particular one or more magnetic field sensor elements having the first main detection direction together relative to one or more magnetic field sensor elements with the second main detection direction with respect to the sensitive one Main level and the defined detection point substantially arranged concentrically. Under the common detection point is particularly preferably understood a common reading point of the sensor.

The sensor preferably has a signal processing circuit which is designed such that it generates at least one of the element output signals of the first and the second magnetic field sensor element, in particular a digital sensor output signal which contains at least one of the following information:
The relative and / or absolute position between encoder and sensor and / or the relative speed between the encoder and sensor and / or the relative direction of movement between the encoder and sensor and / or the magnetic field strength of the magnetic field detected by the sensor and / or the distance between the encoder and Sensor and / or at least one information about the plausibility of the sensor output signal.

Of the Sensor expediently comprises a chip, which at least the first and the second magnetic field sensor element as well In particular, the signal processing circuit has. The chip is particularly preferably designed as an ASIC, and includes in particular preferably at least one integrated Hall element and a magnetoresistive sensor element, which, for example, on an outer surface of the Chips on an additional insulating layer in thin-film technology is applied.

The the first and second magnetic field sensor elements are alternatively preferable connected by wire bond or flip chip directly or indirectly.

It it is preferred that the sensor comprises at least one magnetic means, in particular has a permanent magnet. This is particularly preferred magnetized so that it is a magnetic support field for at least one designed as an anisotropic magnetoresistive sensor element Magnetic field sensor element provides and / or generates a magnetic field which is due to an encoder, which essentially does not have its own magnetic field is generated, modulated, the encoder for this at least partially formed of soft magnetic material.

It is expedient that the first magnetic field sensor element as AMR sensor element (anisotropic magnetoresistive) and the second Magnetic field sensor element is designed as a Hall element. By means of the AMR element is due to its relatively high sensitivity a relatively precise detection of at least one scale graduation the encoder and / or a defined scale division segment carried out. By means of the additional Hall element Additional information is particularly preferably determined or calculated.

The method is preferably developed by at least one of the following information items being obtained directly or indirectly from the element output signals in a signal processing circuit:
The relative and / or absolute position between encoder and sensor and / or the relative speed between encoder and sensor and / or the relative direction of movement between encoder and sensor and / or the magnetic field strength of the magnetic field detected by the sensor and / or the distance between the encoder and sensor and / or at least one information about the plausibility of the sensor output signal.

Especially is the first magnetic field sensor element as a magnetoresistive Sensor element formed and the second magnetic field sensor element as a Hall element and the two element output signals are so generates that relative to each other a phase shift amount of have substantially 90 °.

It is preferred that information about the relative Movement direction between encoder and sensor is determined by with respect to the element output signals of the least one first and second magnetic field sensor element the slope, in particular the sign of the slope, the first element output in a first zero crossing with a slope, in particular the sign the slope, of the second element output signal in one of the first Zero crossing leading or trailing zero crossing compared or taken into account. Alternatively, preferably an information about the relative direction of movement between Encoder and sensor determined by a zero crossing of a Element output signal, the sign of the value of an element output signal another magnetic field sensor element is determined. This is in particular by means of a comparator, the value of the element output signal of another magnetic field sensor element having an average voltage of the element output signals compared. Alternatively, preferably, information about the relative direction of movement between sensor and encoder Determining a relative change in position and / or a Angle change between the first element output signal and the second element output signal, in particular by the Angle of the first element output at a first time and the angle of the second element output signal to a second one Date determined and taken into account, this being first and second time have a time interval from one another, which is less than half the period of the element output signals. As a result, to determine the relative direction of motion no Zero crossing of one of the element output signals considered become.

The magnetic field strength or information about the magnetic field strength of the magnetic field detected by the sensor is preferably determined by, essentially at the time a zero crossing of an element output signal, the value of the element output signal a different magnetic field sensor element is taken into account. In particular, at a zero crossing of the element output signal a magnetoresistive sensor element, the value of an element output signal a Hall element, particularly preferred directly from this value the field strength and / or the magnetic Flux density determined. By the phase shift of the element output signals to each other, the zero crossings of an element output signal essentially as an indicator of the existence of the maximum Amount of the element output signal of the other magnetic field sensor element used or as "trigger points" to determine the magnetic field strength can be used. At least an information about the magnetic field strength and / or flux density is then most preferred the distance or the air gap length between encoder and Sensor detected. Alternatively, preferably, the magnetic field strength of the magnetic field detected by the sensor calculated by the circle radius of both, in particular as sinusoidal and cosinusoidal, Element output signals is determined and more preferably the Root from the sum, the sine square of the value of the first element output signal and the cosine square of the value of the second element output signal, each at a defined time, is calculated.

Under a zero crossing is expediently one Under or exceeding a defined value, in particular an average, understood by an element output.

The relative direction of movement between encoder and sensor, the magnetic Field strength of the magnetic field detected by the sensor, the distance between encoder and sensor, and the at least one information about the plausibility of the sensor output signal are preferred Further information.

It is appropriate that in a signal processing circuit the sensor and / or in an electronic connected to the sensor Control unit position information and / or speed information is determined by interpolation. In particular, the Element output signal of a Hall element for correction or interpolation used an element output signal of an AMR sensor element.

Prefers the magnetic field strength becomes out of the element output signal a Hall element and in the evaluation of the element output signal an AMR sensor element for correction, particularly with regard to the waveform of the AMR element output signal, which is particularly preferably dependent on the magnetic Field strength has harmonics.

For determining or calculating the relative position and / or speed between the sensor and the encoder, an arctangent function is preferably applied to the quotient of the values of the element output signals of the first and the second magnetic field sensor element, expediently at a common time, wherein these element output signals are in particular substantially sinusoidal or cosinusoidal signals are formed, which are phase-shifted at, substantially, 90 ° to each other. This quotient, to which the arctangent function is applied for determining position and / or velocity information, is particularly preferred for the respective pairs of values of the element output signals of the first and second magnetic field sensor element in a memory unit, very particularly preferably as a table of experimentally determined and / or by simulation or as a "look-up table" deposited. This storage unit is conveniently accessed in the application of the arctangent function. By storing values in a look-up table and using them when using the arctangent function, systematic errors, in particular with regard to the signal shape of the element output signals, can be corrected relatively easily and precisely, or errors resulting therefrom can be avoided.

The Element output signal of a Hall element is preferably for "flip-detection" of the element output signal an AMR sensor element used. Under "flipping" is understood a signal disturbance, which is in a undesirable doubling of the signal frequency of the element output signal the AMR sensor element expresses and example from a faulty relative positioning between sensor and Encoder results.

Of the Sensor expediently comprises at least one AMR sensor element and is arranged relative to the encoder so that the AMR sensor element operated in low-field operation or as a field probe becomes.

Under the magnetic field strength of the magnetic field measured and / or is determined, is also or alternatively the magnetic Flow density or other field size understood.

Of the Sensor is preferred as a speed sensor, in particular as a wheel speed sensor, educated.

The Sensor arrangement according to the invention and the inventive Methods are provided for use in all technical fields in which a rotational or translational relative movement and / or a relative position between encoder and sensor detected shall be. The inventive compounds are preferred Sensor arrangement and the inventive method for use in motor vehicles or in automation technology intended. In particular, its use is safety-critical Applications provided, particularly preferably in motor vehicle brake and / or control systems.

Further preferred embodiments will be apparent from the dependent claims and the following descriptions of embodiments on the hand of figures.

It show in a schematic representation

1 An embodiment of a sensor arrangement in which the sensor is arranged with respect to its first sensitive main plane parallel to the encoder track surface of the encoder,

2 an exemplary sensor arrangement in which the sensor is arranged with respect to its first sensitive main plane perpendicular to the encoder track surface of the encoder,

3 exemplary signal waveforms of the element output signals of the first and second magnetic field sensor elements,

4 Exemplary embodiments for the relative arrangement of one or more magnetic field sensor elements with a first main detection direction to one or more magnetic field sensor elements with a second main detection direction,

5 an embodiment in which the sensor is connected to an electronic control unit, and

6 an exemplary sensor, which is designed as an integrated chip.

In 1 an embodiment of a sensor arrangement is shown, in which sensor 1 with respect to its first sensitive main plane 3 parallel opposite encoder track surface 4 of the encoder 2 is arranged. encoder 2 is alternately coded and has north-south pole pairs N, S, between which the magnetic field B →, of which only one field line is illustrated as an example, is expressed. sensor 1 comprises two magnetic field sensor elements, not shown, one of which is formed as an AMR sensor element and has a first main detection direction in the direction of the y-axis of the illustrated Cartesian coordinate system or parallel to this y-axis. The second magnetic field sensor element is designed as a Hall element and has a second main detection direction in the direction or parallel to the z-axis. These two magnetic field sensor elements detect this through the encoder 2 generated and in the course of relative movements between encoder 2 and sensor 1 from the encoder 2 modulated magnetic field in a common detection or reading point. As a result of this and because of the element technologies "AMR" and "Hall" used for the magnetic field sensor elements, the element output signals of these two magnetic field sensor elements have a phase shift of 90 ° relative to each other. The sensor 1 may have relatively compact dimensions, since the phase shift between the element output signals not by a spaced apart arrangement of the magnetic field sensor elements in relative Movement direction, parallel to the y-axis, between sensor 1 and encoders 2 , is produced. The AMR sensor element is arranged with respect to its not shown sensitive structures in the sensitive main plane or parallel to the encoder track surface 4 arranged. The AMR sensor element is thus operated in weak-field operation. Due to this parallel alignment between sensor 1 and encoders 2 is a relatively flat and space-saving design of the sensor array he goes.

2 shows an exemplary sensor arrangement in which sensor 1 with respect to its first sensitive main plane 3 perpendicular to the encoder track surface 4 of the encoder 2 is aligned. An unillustrated first magnetic field sensor element, which is designed as an AMR sensor element and arranged with respect to its sensitive structures parallel to the sensitive main plane, detects the magnetic field B → with respect to its components in the Z direction. The second magnetic field sensor element, which is not shown, which is formed as a Hall element and also with respect to its sensitive structures parallel to the sensitive main plane 3 is arranged and thus parallel to the AMR sensor element, detects y-components of the magnetic field B →.

In 3 are exemplary element output signals of the magnetic field sensor elements of the sensor array 1 shown. In this case, the detected magnetic flux density B of the magnetic field components in the y-direction is shown in dashed lines.

4 shows in the representations a) to g) various, exemplary arrangements of the at least first magnetic field sensor element 5 or a group of magnetic field sensor elements 5a . 5b . 5c . 5d with the first main detection direction relative to the second magnetic field sensor element 6 or a group of magnetic field sensor elements 6a . 6b . 6c . 6d with the second main detection direction. The magnetic field sensor elements having the first main detection direction are configured, for example, as AMR sensor elements, and the magnetic field sensor elements having the second main detection direction are formed as Hall elements, which are hatched. By way of example, all magnetic field sensor elements with respect to their sensitive structures are arranged parallel or in the first sensitive main plane of the sensor or lie flat against the first sensitive main plane. The one or more AMR sensor elements 5 . 5a . 5b . 5c . 5d are each substantially concentric with the one or more Hall elements 6 . 6a . 6b . 6c . 6d arranged and have a common defined detection point 7 on. The AMR sensor elements 5 . 5a . 5b . 5c . 5d have the first main detection direction in the y direction and the Hall elements 6 . 6a . 6b . 6c . 6d the second main detection direction in the z direction, each according to an in 1 shown relative alignment between sensor and encoder. Regarding one in 2 As shown, the relative orientation between sensor and encoder, the AMR sensor elements have the first main detection direction in the z-direction and the Hall elements, the second main detection direction in the y-direction.

5 exemplifies the connection of a sensor 1 to an electronic control unit ECU by means of a two-wire interface. sensor 1 has an AMR sensor element 5 with element output signal SE1 and a Hall element 6 with element output signal SE2. The element output signals SE1, SE2 are respectively pre-amplified in a signal conditioning stage V1, V2 and a signal processing circuit 8th which generates a digital sensor output signal Sout, which is transmitted to the ECU. This sensor output signal contains exemplary position information, speed information and various additional information.

In 6 is an exemplary, integrated sensor designed as a chip 1 displayed. This comprises an ASIC which has a signal processing circuit. A hall element 6 , as the second magnetic field sensor element, is integrated in the ASIC. The ASIC has an insulating layer on its upper outer surface 9 on which a magnetoresistive sensor element 5 , as the first magnetic field sensor element, is arranged in thin-film technology.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 102005039280 A1 [0002]

Claims (14)

Position and / or speed sensor arrangement comprising a sensor ( 1 ) with at least one first sensitive main plane ( 3 ) and an encoder ( 2 ) with at least one encoder track surface ( 4 ), whereby the sensor ( 1 ) one from the encoder ( 2 ) can detect and / or modulated magnetic field (B →) and wherein the sensor at least a first ( 5 ) and a second one ( 6 ) Magnetic field sensor element, wherein the first magnetic field sensor element ( 5 ) has at least one first main detection direction (y →) and the second magnetic field sensor element ( 6 ) has an at least second main detection direction (z →) different from the first main detection direction, characterized in that the first ( 5 ) and the second ( 6 ) Magnetic field sensor element are arranged so that at least one element output signal (SE1) of the first magnetic field sensor element ( 5 ) to at least one element output signal (SE2) of the second magnetic field sensor element ( 6 ) has a phase shift amount between 75 ° and 105 °. Sensor arrangement according to claim 1, characterized that this phase shift amount is substantially 90 °. Sensor arrangement according to claim 1 or 2, characterized in that the sensor ( 1 ) with respect to its first sensitive main plane ( 3 ) substantially parallel to the encoder track surface ( 4 ) of the encoder ( 2 ) is aligned. Sensor arrangement according to at least one of claims 1 to 3, characterized in that the first ( 5 ) and the second ( 6 ) Magnetic field sensor element each having one or more sensitive structures, which are each arranged substantially in a structural plane, wherein the first and the second magnetic field sensor element are arranged with respect to their respective structural plane substantially parallel to each other or in a common plane. Sensor arrangement according to at least one of the claims 1 to 4, characterized in that the first main detection direction (y →) with respect to the second main detection direction (z →) is essentially 90 ° turned pronounced. Sensor arrangement according to at least one of claims 1 to 5, characterized in that the first magnetic field sensor element ( 5 ) is formed with the first main detection direction as a magnetoresistive sensor element and the second magnetic field sensor element ( 6 ) is formed with the second main detection direction as a Hall element. Sensor arrangement according to at least one of claims 1 to 6, characterized in that at least the first ( 5 ) and the second ( 6 ) Magnetic field sensor element are arranged so that they the magnetic field (B →) with respect to the first sensitive main plane ( 3 ) of the sensor ( 1 ) in a defined common detection point ( 7 ) essentially collectively. Sensor arrangement according to claim 7, characterized in that a ( 5 ) or multiple magnetic field sensor elements ( 5a . 5b . 5c . 5d ) with the first main detection direction (y →, z →) together relative to one ( 6 ) or multiple magnetic field sensor elements ( 6a . 6b . 6c . 6d ) with the second main detection direction (z →, y →) with respect to the main sensitive plane ( 3 ) and the defined detection point ( 7 ) are arranged substantially concentrically. Sensor arrangement according to at least one of claims 1 to 8, characterized in that the sensor ( 1 ) a signal processing circuit ( 8th ) which is designed to be at least from the element output signals (SE1, SE2) of the first ( 5 ) and the second ( 6 ) Magnetic field sensor element, in particular digital, sensor output signal (Sout) generated, which includes at least one of the following information: the relative and / or absolute position between encoder and sensor and / or the relative speed between the encoder and sensor and / or the relative direction of movement between the encoder and Sensor and / or the magnetic field strength of the magnetic field detected by the sensor and / or the distance between the encoder and the sensor and / or at least one information about the Plausibi quality of the sensor output signal. Sensor arrangement according to at least one of claims 1 to 9, characterized in that the sensor ( 1 ) comprises a chip which comprises at least the first ( 5 ) and the second ( 6 ) Magnetic field sensor element and in particular the signal processing circuit (ASIC). Method for position and / or speed measurement with a sensor arrangement, in particular according to at least one of claims 1 to 10, in which by means of a sensor ( 1 ), which has at least one first main sensitive plane ( 3 ) and at least a first ( 5 ) and a second one ( 6 ) Magnetic field sensor element, a through an encoder ( 2 ) is detected and / or modulated magnetic field (B →) is detected, wherein the first magnetic field sensor element ( 5 ) has at least one first main detection direction (y →) and the second ( 6 ) Magnetic field sensor element at least a second, different from the first main detection direction, the main detection direction (z →), characterized in that at least one element output signal (SE1) of the first magnetic field sensor element ( 5 ) and at least one element output signal (SE2) of the second magnetic field sensor element ( 6 ) in the course of the detection of the magnetic field (B →), wherein these two element output signals (SE1, SE2) relative to each other have a phase shift amount between 75 ° and 105 °. Method according to claim 11, characterized in that in a signal processing circuit ( 8th ) from the element output signals (SE1, SE2) at least one of the following information is obtained directly or indirectly: the relative and / or absolute position between the encoder and sensor and / or the relative speed between encoder and sensor and / or the relative direction of movement between encoder and sensor and / or the magnetic field strength of the magnetic field detected by the sensor and / or the distance between the encoder and the sensor and / or at least information about the plausibility of the sensor output signal. Method according to claim 11 or 12, characterized in that the first magnetic field sensor element ( 5 ) is formed as a magnetoresistive sensor element and the second magnetic field sensor element ( 6 ) as a Hall element and the two element output signals (SE1, SE2) in particular relative to each other have a phase shift amount of substantially 90 °. Use of the sensor arrangement according to at least one of claims 1 to 10 in motor vehicles, in particular as a speed sensor arrangement.