Methods and sensor devices for position detection

Abstract

A method for determining a position of a magnetic field sensor in a plane defined by a first direction and a second direction perpendicular to the first direction includes an act of measuring, by the magnetic field sensor, a 3D magnetic field vector of a magnetic field generated by a magnet separated from the plane by an air gap, the 3D magnetic field vector including a first magnetic field component in the first direction, a second magnetic field component in the second direction, and a third magnetic field component in a third direction perpendicular to the first direction and the second direction. The method further includes an act of determining a first displacement between the magnetic field sensor and the magnet in the first direction based on the first magnetic field component and the third magnetic field component.The method further includes an act of determining a second displacement between the magnetic field sensor and the magnet in the second direction based on the second magnetic field component and the third magnetic field component.

Description

Technical area

[0001] The present disclosure relates to methods and sensor devices for position detection. In particular, the present disclosure relates to methods for determining a position of a magnetic field sensor in a plane and sensor devices for performing such methods. background

[0002] In many technical applications, different components must be positioned relative to each other as precisely as possible. For example, autonomous robots must automatically position themselves at wireless charging stations. The efficiency of the charging process can be negatively impacted if the robots are not positioned precisely enough relative to the charging point.

[0003] The document US 2015 / 0 292 906 A1 concerns a system for measuring the relative position between two separate components. The document US 2012 / 0 262 162 A1 concerns a bidirectional magnetic position sensor with field rotation.

[0004] Manufacturers and developers of sensor devices for positioning purposes are constantly striving to improve their products. In particular, it may be desirable to develop efficient and fast methods for determining the position of an object. Additionally, it may be desirable to provide associated sensor devices for performing such methods. Summary

[0005] One aspect of the present disclosure relates to a method for determining a position of a magnetic field sensor in a plane defined by a first direction and a second direction perpendicular to the first direction. The method comprises an act of measuring, by the magnetic field sensor, a 3D magnetic field vector of a magnetic field generated by a magnet separated from the plane by an air gap, the 3D magnetic field vector comprising a first magnetic field component in the first direction, a second magnetic field component in the second direction, and a third magnetic field component in a third direction perpendicular to the first direction and the second direction. The method further comprises an act of determining a first displacement between the magnetic field sensor and the magnet in the first direction based on the first magnetic field component and the third magnetic field component.The first shift is determined based on. Δx=kxtan−1(BxBz), where Δx is the first displacement, k x is a first proportionality factor, and B x and B z the first magnetic field component and the third magnetic field component, respectively. The method further comprises a process of determining a second displacement between the magnetic field sensor and the magnet in the second direction based on the second magnetic field component and the third magnetic field component. The second displacement is determined based on Δy=kytan−1(ByBz), where Δy is the second displacement, k y is a second proportionality factor, and B y and B z the second magnetic field component and the third magnetic field component respectively.

[0006] Another aspect of the present disclosure relates to a sensor device. The sensor device comprises a magnetic field sensor. The magnetic field sensor is configured to move in a plane defined by a first direction and a second direction perpendicular to the first direction. The magnetic field sensor is further configured to measure a 3D magnetic field vector of a magnetic field generated by a magnet separated from the plane by an air gap. The 3D magnetic field vector comprises a first magnetic field component in the first direction, a second magnetic field component in the second direction, and a third magnetic field component in a third direction perpendicular to the first direction and the second direction. The sensor device further comprises a calculation unit.The calculation unit is configured to determine a first displacement between the magnetic field sensor and the magnet in the first direction based on the first magnetic field component and the third magnetic field component. The first displacement is determined based on. Δx=kxtan−1(BxBz), where Δx is the first displacement, k x is a first proportionality factor, and B x and B z the first magnetic field component and the third magnetic field component, respectively. The calculation unit is further configured to determine a second displacement between the magnetic field sensor and the magnet in the second direction based on the second magnetic field component and the third magnetic field component. The second displacement is determined based on Δy=kytan−1(ByBz), where Δy is the second displacement, k y is a second proportionality factor, and B y and Bz the second magnetic field component and the third magnetic field component respectively. Short description of the drawings

[0007] Methods and devices according to the disclosure are described in more detail below based on the drawings. Similar reference numerals may denote correspondingly similar parts. The technical features of the various illustrated examples may be combined, provided they are not mutually exclusive, and / or may be selectively omitted if not described as necessarily required. Fig. 1 includes the Fig. 1A and Fig. 1B, which schematically illustrate a perspective view and a top view of a sensor device 100 according to the disclosure. Fig. 2 illustrates a flow diagram of a method for determining a position of a magnetic field sensor in a plane according to the disclosure. Fig. 3 includes the Fig. 3A to Fig. 3C, which schematically illustrate a perspective view and two side views of a magnetic field generated by a magnet. Fig. 4 includes the Fig. 4A and Fig. 4B, illustrating a relationship between a first angle of a magnetic field vector and a first displacement between a magnetic field sensor and a magnet generating the magnetic field. Fig. 5 includes the Fig. 5A and Fig. 5B, illustrating a relationship between a second angle of a magnetic field vector and a second displacement between a magnetic field sensor and a magnet generating the magnetic field. Fig. 6 includes the Fig. 6A to Fig. 6C, which schematically illustrate an exemplary application of a method and a sensor device according to the disclosure. Fig. 7 schematically illustrates a top view of a sensor device 700 according to the disclosure. Fig. 8 schematically illustrates a side view of a sensor device 800 according to the disclosure. Detailed description

[0008] The methods and sensor devices described herein can be used to determine a relative position between a magnetic field sensor and a magnet. An object can be mechanically coupled to the magnetic field sensor or the magnet, such that a position of the object can be linked to the determined relative position of the magnetic field sensor and the magnet. The described methods and sensor devices are not limited to a particular application, but can be used in a variety of applications. In one example, the methods and sensor devices can be used in a wireless charging operation. In such an operation, the methods and sensor devices can be used by an autonomous robot to appropriately position itself relative to a wireless charging station. In another example, the methods and sensor devices can be used in a headlight alignment operation (e.g.,of a car). In such a process, a misalignment of an LED circuit board can be detected and adjusted. In yet another example, the methods and sensor devices can be used in a camera stabilization process. In such a process, the methods and sensor devices can be used for optical image stabilization, autofocus, and / or optical zoom (e.g., of a mobile phone). Here, a position of one or more lenses can be determined and used for their alignment.

[0009] With reference to Fig. 1 illustrates a plane defined by a first direction (x-direction) and a second direction (y-direction) perpendicular to the first direction. A third direction (z-direction) may extend perpendicular to the first direction and the second direction. A sensor device 100 may include a magnetic field sensor 2 and a calculation unit 10 connected thereto. The magnetic field sensor 2 may be configured to move in the xy-plane, in particular in a sector of the xy-plane that may be referred to as a movement range 4. The sensor device 100 may further include a magnet 6 separated from the xy-plane by an air gap 8. The magnet 6 may or may not be considered part of the sensor device 100.

[0010] In the illustrated example, the movement range 4 of the magnetic field sensor 2 may have the shape of a rectangle. In further examples, the shape of the movement range 4 may vary depending on the application under consideration. For example, the movement range 4 may measure approximately 10 mm in the x-direction and approximately 20 mm in the y-direction. However, these dimensions are not limiting in any way and are provided for illustrative purposes only.

[0011] The magnet 6 can be positioned at a reference position directly below the origin of the illustrated coordinate system. That is, the magnet 6 can be arranged on a line extending perpendicular to the xy plane through the coordinate origin. For example, the magnet 6 can be axially magnetized in the z-direction. In this respect, the upper half of the magnet 6 can correspond to a magnetic north pole, while the lower half of the magnet 6 can correspond to a magnetic south pole, or vice versa.

[0012] The magnetic field sensor 2 can be configured to measure a 3D magnetic field vector of the magnetic field generated by the magnet 6. The measured 3D magnetic field vector can include three magnetic field components in the x-direction, y-direction, and z-direction. The magnetic field sensor 2 can include one or more sensor elements that are not limited to a specific sensing technology. For example, a sensor element of the magnetic field sensor 2 can be a Hall sensor element, a magnetoresistive sensor element, a vertical Hall sensor element, or a fluxgate sensor element. A magnetoresistive xMR sensor element can be an AMR (Anisotropic Magneto-Resistive) sensor element, a GMR (Giant Magneto-Resistive) sensor element, or a TMR (Tunnel Magneto-Resistive) sensor element. In a specific case, the magnetic field sensor 2 can include or correspond to a 3D Hall sensor.The magnetic field sensor 2 and its sensor elements can be contained in a semiconductor chip.

[0013] Physical signals detected by the magnetic field sensor 2 can be converted into electrical signals and can be forwarded to other components (e.g., the calculation unit 10) for further processing or evaluation. In the illustrated case, a connection between the magnetic field sensor 2 and the calculation unit 10 is only qualitatively indicated by a dashed line. In practice, the calculation unit 10 can be implemented in various forms. In one example, the calculation unit 10 can include a digital signal processor, wherein the digital signal processor and the magnetic field sensor 2 can be integrated into a same semiconductor chip. In another example, the magnetic field sensor 2 can be included in a semiconductor chip, and the calculation unit 10 can be included in a microcontroller external to the semiconductor chip.

[0014] In the top view of Fig. 1B, the magnetic field sensor 2 can be offset from the coordinate origin and the magnet 6. In this regard, Δx can denote a first displacement between the magnetic field sensor 2 and the magnet 6 in the x-direction, while Δy can denote a second displacement between the magnetic field sensor 2 and the magnet 6 in the y-direction. A target position 12 of the magnetic field sensor 2 can be identified with the coordinate origin.

[0015] In some applications, a goal may be to move the magnetic field sensor 2 to the target position 12. For example, autonomous robots may need to be regularly recharged at a charging station located at a target position. In such a case, the magnetic field sensor 2 may be mechanically coupled to the robot, and the magnet 6 may be mechanically coupled to the charging station. For charging purposes, the position of the magnetic field sensor 2 (and thus the position of the robot) can be determined, and based on this, the robot can be moved to the charging station.

[0016] With reference to Fig. 2 illustrates a flowchart of a method according to the disclosure. The method is for determining a position of a magnetic field sensor in a plane defined by a first direction and a second direction perpendicular to the first direction. The method is described in a general manner to qualitatively specify aspects of the disclosure. For example, the method for determining the position of the magnetic field sensor 2 in the example of Fig. 1. It is understood that the method may include further aspects. For example, the method may be extended by any of the aspects described in connection with other examples described herein.

[0017] At 14, the magnetic field sensor may measure a 3D magnetic field vector of a magnetic field generated by a magnet separated from the plane by an air gap. The 3D magnetic field vector may include a first magnetic field component in the first direction, a second magnetic field component in the second direction, and a third magnetic field component in a third direction perpendicular to the first direction and the second direction. At 16, a first displacement between the magnetic field sensor and the magnet in the first direction may be determined based on the first magnetic field component and the third magnetic field component. At 18, a second displacement between the magnetic field sensor and the magnet in the second direction may be determined based on the second magnetic field component and the third magnetic field component. The following describes the method of Fig. 2 described in more detail.

[0018] With reference to Fig. Figure 3A schematically illustrates the magnetic field generated by the axially magnetized magnet 6 in the movement region 4. In particular, a plurality of magnetic field vectors are shown, representing the magnetic field at several positions in the movement region 4. Fig. Figure 3B illustrates the magnetic field of Fig. 3A when viewed in the y-direction, while Fig. 3C the magnetic field of Fig. 3A when viewed in the x-direction.

[0019] An exemplary 3D magnetic field vector 20 of the plurality of illustrated magnetic field vectors will now be considered. In the side view of Fig. 3B, the 3D magnetic field vector 20 can be divided into its first magnetic field component B z in the x-direction and its third magnetic field component B z in the z-direction. A first angle β1 between the 3D magnetic field vector 20 and the z-direction can be determined by a first arctangent value β1=tan−1(BxBz)

[0020] In the side view of Fig. 3C, the 3D magnetic field vector 20 can be divided into its second magnetic field component B y in the y-direction and its third magnetic field component B z in the z-direction. A second angle β2 between the 3D magnetic field vector 20 and the z-direction can be represented by a second arctangent value β2=tan−1(ByBz)

[0021] Each position of the magnetic field sensor 2 in the movement range 4 can be specified by its displacement with respect to the target position 12, ie by a pair of values ​​(Δx, Δy). Fig. Figure 4A illustrates a dependency between the first angle β1 (or the first arctangent tan−1(BxBz)) and the position of the magnetic field sensor 2 (ie (Δx, Δy)) in the considered movement range 4. This means that each position of the magnetic field sensor 2 in the movement range 4 can be mapped to a value of the first angle β1 and / or vice versa. For example, the dependence between the first angle β1 and the position (Δx, Δy) can be obtained by measurements and / or simulation results. As can be seen from Fig. As can be seen from Figure 4A, the dependency can be represented by a first quasi-level (or essentially by a first level).

[0022] Fig. Figure 4B illustrates a relationship between the first angle β1 and the x-position Δx of the magnetic field sensor 2 in the considered movement range 4 for a fixed value of Δy. As can be seen from Fig. 4B, a first dependence between the first angle β1 and the first displacement Δx may be quasi-linear (or substantially linear), ie Δx=kxtan−1(BxBz) where k x a first proportionality factor corresponding to the slope of the Fig. 4B. The factor k x can be determined in a calibration procedure described later.

[0023] Similar to the previous discussion, Fig. 5A a dependency between the second angle β2 (or the second arctangent tan−1(ByBz)) and the position of the magnetic field sensor 2 (ie (Δx, Δy)) in the considered movement range 4. This means that each position of the magnetic field sensor 2 in the movement range 4 can be mapped to a value of the second angle β2 and / or vice versa. For example, the dependence between the second angle β2 and the position (Δx, Δy) can be obtained by measurements and / or simulation results. As can be seen from Fig. As can be seen in Figure 5A, the dependency can be represented by a second quasi-level (or essentially by a second level).

[0024] Fig. Figure 5B illustrates a relationship between the second angle β2 and the y-position Δy of the magnetic field sensor 2 in the considered movement range 4 for a fixed value of Δx. As can be seen from Fig. 5B, a second dependence between the second angle β2 and the second displacement Δy may be quasi-linear (or substantially linear), ie Δy=kytan−1(ByBz) where k y a second proportionality factor corresponding to the slope of the (quasi-)straight line of Fig. 5B. The factor k y can be determined in a calibration procedure described later.

[0025] It should be noted that the range of motion 4 can be chosen so that the dependencies of the Fig. 4 and Fig. 5 are essentially linear. However, the dependencies between the angles (β1, β2) and the displacements (Δx, Δy) may not necessarily be linear (or quasi-linear) at positions outside the range of motion 4.

[0026] Referring again to the sensor device 100 of Fig. 1 and the procedure of Fig. 2, the magnetic field sensor 2 can be located at a position (Δx, Δy) to be determined during operation of the sensor device 100. In step 14, the magnetic field sensor 2 can measure the 3D magnetic field vector (B x , B y , B z) of the magnetic field generated by the magnet 6 at the position (Δx, Δy). Any other disturbing magnetic fields, such as stray fields, can be considered negligible herein. The obtained measurement signals can then be forwarded to the calculation unit 10 for further processing. In step 16, the calculation unit 10 can calculate the first displacement Δx using equation (3) based on the measured magnetic field components B x and B z In step 18, the calculation unit 10 can calculate the second displacement Δy using equation (4) based on the measured magnetic field components B y and B z calculate.

[0027] It is understood that the procedure of Fig. 2 may include one or more additional steps. Some example steps are given below.

[0028] In an optional further step, the magnetic field sensor 2 and / or the magnet 6 can be moved to a common position based on the calculated displacements Δx and Δy. In this regard, the magnetic field sensor 2 can, for example, be moved to the target position 12 and arranged directly above the magnet 6.

[0029] In a further optional step, the magnetic field sensor 2 can be mechanically coupled to an object. The magnetic field sensor 2 and the coupled object can move in the xy plane, while the magnet 6 can remain at its reference position. The position of the object can correspond to the position of the magnetic field sensor 2 and can thus be determined based on the calculated displacements Δx and Δy.

[0030] In a further optional step, the magnet 6 can be mechanically coupled to an object. In such a case, the magnetic field sensor 2 can remain at a reference position, while the magnet 6 and the object coupled thereto can move in the xy plane. The magnetic field sensor 2 can measure the 3D magnetic field vector of the magnetic field generated by the magnet 6, and the calculation unit 10 can determine the displacements Δx and Δy as previously described. A transmission unit can transmit (in particular wirelessly) the determined displacements to at least one actuator (e.g., a motor). The actuator can receive the determined displacements from the transmission unit and move the magnet 6 (and thus the object) based thereon. The transmission unit and the actuator can be considered part of the sensor device or not.

[0031] In a further optional step, the proportionality factors kx and k y of equations (3) and (4) based on a one-point calibration. In such a calibration process, a non-zero position of the magnetic field sensor 2 can be selected, i.e., a sensor position with an arbitrary first non-zero angle β1 and an arbitrary second non-zero angle β2. For the selected non-zero position, the 3D magnetic field vector (B x , B y , B z ) and the displacements Δx and Δy are measured. Using the measured magnetic field components, the angles β1 and β2 associated with the non-zero position can be calculated based on equations (1) and (2). In addition, as can be seen from the Fig. 4B and Fig. 5B, the values ​​of the angles β1 and β2 for displacement values ​​Δx and Δy of zero are zero. The proportionality factors k x and k ycan thus be determined based on measurements for only a single non-zero position.

[0032] The previously described methods and sensor devices according to the disclosure may surpass conventional concepts. In a first conventional concept, the 3D magnetic field data (B x , B y , B z ) to the positions around the magnet using a lookup table. Such a solution may require a large amount of data to be stored and extensive calibration to generate the lookup table. In a second conventional concept, a gradient descent algorithm can be used. Here, a sensor system can move gradually toward the position of the strongest magnetic field. Such a solution can be slow, as it may require extensive calculations in multiple steps.

[0033] In contrast to such conventional techniques, a relative position between the magnetic field sensor 2 and the magnet 6 can be determined by measuring the 3D magnetic field vector (B x , B y , B z ) and a simple calculation of the displacements Δx and Δy based on equations (1) to (4). There is a simple linear mapping between the angles β1, β2 and the displacements Δx, Δy. The proportionality factors k x and k ycan be determined by a simple one-point calibration as described above. After calculating the displacement values, the magnetic field sensor 2 can move directly to the target position 12. In short, the concepts described herein require only one calibration point (compared to the lookup table used in the first conventional solution) and only one simple calculation step (compared to the multiple calculation steps of the second conventional solution).

[0034] With reference to the Fig. 6A to Fig. Figure 6C illustrates an exemplary application of the previously described methods and sensor devices according to the disclosure. In particular, positioning of an autonomous robot relative to a wireless charging station is shown and discussed.

[0035] In Fig. 6A shows a (particularly autonomous) robot 22 including a magnetic field sensor 2 and a charging station 24 including a magnet 6. The robot 22 may be configured to move in the xy plane and may be offset relative to the charging station 24 by a first displacement Δx in the x-direction and a second displacement Δy in the y-direction.

[0036] In Fig. 6B, the magnetic field sensor 2 can measure a 3D magnetic field vector of the magnetic field generated by the magnet 6. A calculation unit (not illustrated) can determine the displacements Δx and Δy as previously described. Based on this, the robot 22 can move to a target position where the magnetic field sensor 2 is located directly above the magnet 6.

[0037] In Fig. 6C, the robot 22 can move in the z-direction toward the charging station 24 so that a charging port of the robot 22 can connect to the charging station 24 and a process for charging the robot 22 can begin.

[0038] In addition to the position detection described above, the methods and sensor devices according to the disclosure may be configured to measure a rotational or angular movement of a target. In this context, Fig. 7 is a plan view of a sensor device 700 according to the disclosure. The sensor device 700 may include some or all of the features of the sensor device 100 of Fig. 1 included.

[0039] A magnetic field sensor 2 can be offset from a target position 12 by the displacements Δx and Δy as described above. A first angular coordinate (or rotation angle) θ1 of the magnetic field sensor 2 in the xy plane can be determined based on the displacements Δx and Δy by θ1=tan−1(ΔxΔy)

[0040] Alternatively or additionally, a second angular coordinate (or rotation angle) θ2 of the magnetic field sensor 2 in the xy plane can be determined based on θ2=tan−1(ΔyΔx)=π2−θ1

[0041] Based on the determined angular coordinate(s), a rotational movement of an object that is mechanically coupled to one of the magnetic field sensor 2 or the magnet 6 can be determined.

[0042] With reference to Fig. 8, a sensor device 800 may include a circuit board 26 and a magnetic field sensor 2 arranged thereon. Additionally, the sensor device 800 may include a magnet 6, which may be encapsulated in an encapsulation 28. The encapsulation 28 may be configured to rotate about an axis of rotation 30 extending in the z-direction, wherein the magnet 6 may be offset from the axis of rotation 30. Rotation of the encapsulation 28 about the axis of rotation 30 may result in a movement of the magnet 6 along a circular curve. The magnetic field sensor 2 may be aligned with the axis of rotation 30.

[0043] During rotation of the encapsulation 28 and the magnet 6 embedded therein, the magnetic field sensor 2 can measure the 3D magnetic field vector of the magnetic field generated by the magnet 6. Angular coordinates can then be calculated by a calculation unit based on the measured magnetic field components and equations (5a) and / or (5b). The rotational movement and an angular position of the magnet 6 can be determined based on the calculated angular coordinates.

[0044] This in conjunction with the Fig. 7 and Fig. The concept described in Figure 8 may be configured to determine a rotational motion and / or a rotation angle of an object mechanically coupled to the magnet 6 (or to the encapsulation 28), wherein rotation of the object may be based on a rotation of the magnet 6. The object may be of any type. In one example, the object may include or correspond to an automotive component. An automotive component may, for example, be a steering wheel of a vehicle, in particular a steering wheel of an electric power steering system. In another example, the described concept may determine rotation angles of a valve or a component of a valve control system. In another example, the object may include or correspond to a windshield wiper or another component of a windshield wiper application. In yet another example, rotation angles of a component of a clutch may be determined.In still further examples, the object may include or correspond to a knob, a component of a motor (particularly electric or combustion), a shaft, an anemometer, etc.

[0045] In a specific example, this can be in conjunction with the Fig. 7 and Fig. The concept described in Figure 8 can be used in connection with a safety mechanism for functional safety, in particular functional safety for automobiles. The safety mechanism can be configured to detect a malfunction of an object performing a rotational movement. In this context, a rotation angle can be determined based on the described algorithm according to the disclosure. Additionally, the rotation angle can be determined based on a second, different algorithm. The determined rotation angles can then be compared and / or used for safety plausibility checks. Examples

[0046] In the following, methods for determining a position of a magnetic field sensor in a plane and sensor devices according to the disclosure are described by way of examples.

[0047] Example 1 is a method for determining a position of a magnetic field sensor in a plane defined by a first direction and a second direction perpendicular to the first direction, the method comprising: measuring, by the magnetic field sensor, a 3D magnetic field vector of a magnetic field generated by a magnet separated from the plane by an air gap, the 3D magnetic field vector comprising a first magnetic field component in the first direction, a second magnetic field component in the second direction, and a third magnetic field component in a third direction perpendicular to the first direction and the second direction; determining a first displacement between the magnetic field sensor and the magnet in the first direction based on the first magnetic field component and the third magnetic field component;and determining a second displacement between the magnetic field sensor and the magnet in the second direction based on the second magnetic field component and the third magnetic field component;

[0048] Example 2 is a method according to Example 1, wherein: determining the first displacement comprises calculating a first arctangent value based on the first magnetic field component and the third magnetic field component, and determining the second displacement comprises calculating a second arctangent value based on the second magnetic field component and the third magnetic field component.

[0049] Example 3 is a method according to Example 2, wherein: the first arctangent value represents a first angle between the 3D magnetic field vector and the third direction when viewed in the second direction, and the second arctangent value represents a second angle between the 3D magnetic field vector and the third direction when viewed in the first direction.

[0050] Example 4 is a method according to Example 3, wherein for a range of motion of the magnetic field sensor: a first dependency between the first angle and the first displacement is quasi-linear, and a second dependency between the second angle and the second displacement is quasi-linear.

[0051] Example 5 is a method according to any one of the preceding examples, wherein: the first shift is based on Δx=kx tan−1(BxBz) is determined, where Δx is the first displacement, k x is a first proportionality factor, and Bx and B z the first magnetic field component and the third magnetic field component, respectively, and the second displacement based on Δy=ky tan−1(ByBz) is determined, where Δy is the second displacement, k y is a second proportionality factor, and B y and B z the second magnetic field component and the third magnetic field component respectively.

[0052] Example 6 is a method according to Example 5, further comprising: determining the first proportionality factor and the second proportionality factor based on a one-point calibration.

[0053] Example 7 is a method according to example 5 or 6, wherein determining the first proportionality factor and the second proportionality factor comprises: measuring the first displacement and the second displacement for a non-zero sensor position having a first non-zero angle and a second non-zero angle, measuring the 3D magnetic field vector for the non-zero sensor position, and determining the first proportionality factor and the second proportionality factor based on the measured 3D magnetic field vector and the two measured displacements.

[0054] Example 8 is a method according to any of the preceding examples, further comprising: moving the magnetic field sensor and / or the magnet to a common position based on the first displacement and the second displacement, wherein the magnetic field sensor is arranged directly above the magnet.

[0055] Example 9 is a method according to any of the preceding examples, further comprising: mechanically coupling the magnetic field sensor to an object, and determining a position of the object based on the first displacement and the second displacement.

[0056] Example 10 is a method according to any one of Examples 1 to 8, further comprising: mechanically coupling the magnet to an object, and determining a position of the object based on the first displacement and the second displacement.

[0057] Example 11 is a method according to any of the preceding examples, further comprising: determining an angular coordinate of the magnetic field sensor in the plane based on the first displacement and the second displacement.

[0058] Example 12 is a method according to Example 11, wherein determining the angle coordinate is based on θ=tan−1(ΔxΔy), where θ is the angular coordinate, and Δx and Δy are the first displacement and the second displacement, respectively.

[0059] Example 13 is a method according to example 11 or 12, further comprising: determining a rotational motion of an object mechanically coupled to the magnet based on the angular coordinate.

[0060] Example 14 is a method according to any of the preceding examples, wherein the method is configured to be performed in a wireless charging operation, a headlight aiming operation, or a camera stabilization operation.

[0061] Example 15 is a sensor device comprising: a magnetic field sensor configured to: move in a plane defined by a first direction and a second direction perpendicular to the first direction, and measure a 3D magnetic field vector of a magnetic field generated by a magnet separated from the plane by an air gap, the 3D magnetic field vector comprising a first magnetic field component in the first direction, a second magnetic field component in the second direction, and a third magnetic field component in a third direction perpendicular to the first direction and the second direction;and a calculation unit configured to: determine a first displacement between the magnetic field sensor and the magnet in the first direction based on the first magnetic field component and the third magnetic field component, and determine a second displacement between the magnetic field sensor and the magnet in the second direction based on the second magnetic field component and the third magnetic field component;

[0062] Example 16 is a sensor device according to Example 15, wherein the magnetic field sensor is included in a semiconductor chip and the calculation unit is included in a microcontroller external to the semiconductor chip.

[0063] Example 17 is a sensor device according to Example 15, wherein the calculation unit comprises a digital signal processor, wherein the digital signal processor and the magnetic field sensor are integrated in a same semiconductor chip.

[0064] Example 18 is a sensor device according to any one of Examples 15 to 17, further comprising: a transmission unit configured to transmit the determined first displacement and second displacement; and at least one actuator configured to receive the determined first displacement and second displacement from the transmission unit and move the magnet based thereon.

[0065] Example 19 is a sensor device according to any one of Examples 15 to 18, wherein the magnet is axially magnetized in the third direction.

[0066] Example 20 is a sensor device according to any one of Examples 15 to 19, wherein the magnetic field sensor comprises a 3D Hall sensor.

[0067] Although the present disclosure has been described with reference to illustrative examples, this description is not intended to be interpreted in a limiting sense. Various modifications and combinations of the illustrative examples, as well as other examples of the disclosure, will become apparent to those skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass such modifications or examples.

Claims

[1] A method for determining a position of a magnetic field sensor (2) in a plane defined by a first direction and a second direction perpendicular to the first direction, the method comprising: Measuring, by the magnetic field sensor (2), a 3D magnetic field vector of a magnetic field generated by a magnet (6) separated from the plane by an air gap (8), the 3D magnetic field vector comprising a first magnetic field component in the first direction, a second magnetic field component in the second direction, and a third magnetic field component in a third direction perpendicular to the first direction and the second direction; Determining a first displacement between the magnetic field sensor (2) and the magnet (6) in the first direction based on the first magnetic field component and the third magnetic field component, where the first shift is determined based on Δx=kx tan−1(BxBz) where Δx is the first displacement, k x is a first proportionality factor, and B x and B z the first magnetic field component and the third magnetic field component, respectively; and Determining a second displacement between the magnetic field sensor (2) and the magnet (6) in the second direction based on the second magnetic field component and the third magnetic field component, where the second shift is determined based on Δy=ky tan−1(ByBz) where Δy is the second displacement, k y is a second proportionality factor, and B y and B z the second magnetic field component and the third magnetic field component respectively. [2] The method of claim 1, wherein: determining the first displacement comprises calculating a first arctangent value based on the first magnetic field component and the third magnetic field component, and determining the second displacement comprises calculating a second arctangent value based on the second magnetic field component and the third magnetic field component. [3] The method of claim 2, wherein: the first arctangent value represents a first angle between the 3D magnetic field vector and the third direction when viewed in the second direction, and the second arctangent represents a second angle between the 3D magnetic field vector and the third direction when viewed in the first direction. [4] Method according to claim 3, wherein for a movement range (4) of the magnetic field sensor (2): a first dependence between the first angle and the first displacement is quasi-linear, and a second dependence between the second angle and the second displacement is quasi-linear. [5] The method of any preceding claim, further comprising: determining the first proportionality factor and the second proportionality factor based on a one-point calibration. [6] A method according to any one of the preceding claims, wherein determining the first proportionality factor and the second proportionality factor comprises: Measuring the first displacement and the second displacement for a non-zero sensor position with a first non-zero angle and a second non-zero angle, Measuring the 3D magnetic field vector for the non-zero sensor position, and Determining the first proportionality factor and the second proportionality factor based on the measured 3D magnetic field vector and the two measured displacements. [7] Method according to one of the preceding claims, further comprising: moving the magnetic field sensor (2) and / or the magnet (6) to a common position based on the first displacement and the second displacement, wherein the magnetic field sensor (2) is arranged directly above the magnet (6). [8] Method according to one of the preceding claims, further comprising: mechanically coupling the magnetic field sensor (2) with an object, and Determine a position of the object based on the first displacement and the second displacement. [9] A method according to any one of claims 1 to 7, further comprising: mechanically coupling the magnet (6) to an object, and Determine a position of the object based on the first displacement and the second displacement. [10] Method according to one of the preceding claims, further comprising: determining an angular coordinate of the magnetic field sensor (2) in the plane based on the first displacement and the second displacement. [11] The method of claim 10, wherein determining the angular coordinate is based on θ=tan−1(ΔxΔy) where θ is the angular coordinate and Δx and Δy are the first displacement and the second displacement, respectively. [12] The method of claim 10 or 11, further comprising: determining a rotational movement of an object mechanically coupled to the magnet (6) based on the angular coordinate. [13] The method of any preceding claim, wherein the method is configured to be performed in a wireless charging process, a headlight alignment process, or a camera stabilization process. [14] Sensor device comprising: a magnetic field sensor (2) configured to: to move in a plane defined by a first direction and a second direction perpendicular to the first direction, and to measure a 3D magnetic field vector of a magnetic field generated by a magnet (6) separated from the plane by an air gap (8), wherein the 3D magnetic field vector comprises a first magnetic field component in the first direction, a second magnetic field component in the second direction, and a third magnetic field component in a third direction perpendicular to the first direction and the second direction; and a calculation unit (10) configured to: to determine a first displacement between the magnetic field sensor (2) and the magnet (6) in the first direction based on the first magnetic field component and the third magnetic field component, where the first shift is determined based on Δx=kx tan−1(BxBz) where Δx is the first displacement, k x is a first proportionality factor, and B x and B z are the first magnetic field component and the third magnetic field component, respectively, and to determine a second displacement between the magnetic field sensor (2) and the magnet (6) in the second direction based on the second magnetic field component and the third magnetic field component, where the second shift is determined based on Δy=ky tan−1(ByBz) where Δy is the second displacement, k y is a second proportionality factor, and B y and B z the second magnetic field component and the third magnetic field component respectively. [15] Sensor device according to claim 14, wherein the magnetic field sensor (2) is contained in a semiconductor chip and the calculation unit (10) is contained in a microcontroller outside the semiconductor chip. [16] Sensor device according to claim 14, wherein the calculation unit (10) comprises a digital signal processor, wherein the digital signal processor and the magnetic field sensor (2) are integrated in a same semiconductor chip. [17] Sensor device according to one of claims 14 to 16, further comprising: a transmission unit configured to transmit the determined first displacement and second displacement; and at least one actuator configured to receive the determined first displacement and second displacement from the transmission unit and to move the magnet (6) based thereon. [18] Sensor device according to one of claims 14 to 17, wherein the magnet (6) is axially magnetized in the third direction. [19] Sensor device according to one of claims 14 to 18, wherein the magnetic field sensor (2) comprises a 3D Hall sensor.

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