Position determination methods and position determination systems
The position determination system effectively addresses the challenge of detecting both rotational and translational movements by employing a magnetic field sensor system with a transmitter and evaluation unit, providing accurate and cost-effective position detection.
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- TDK MICRONAS GMBH
- Filing Date
- 2018-08-06
- Publication Date
- 2026-05-21
AI Technical Summary
Existing position determination systems struggle to accurately and cost-effectively detect both rotational and translational movements of control elements using magnetic field sensors.
A position determination system utilizing a transmitter with a permanent magnet or ferromagnetic component generating two perpendicular magnetic field components, detected by a magnetic field sensor, determines rotational and translational positions through an evaluation unit, allowing for reliable and economical detection.
Enables precise and economical determination of both rotational and translational positions of control elements using a two-dimensional magnetic field sensor, ensuring consistent vector magnitude independent of rotation angle.
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Abstract
Description
[0001] The invention relates to a position determination method and a position determination system.
[0002] From DE 10 2012 001 997 A1, an operating device for an electrical appliance is known. The operating device comprises a sensor unit with a permanent magnet and several magnetic field sensors.
[0003] A method for determining the position and orientation of a translationally and rotationally movable magnetic body is known from DE 10 2015 203 686 A1. Further position determination methods are known from DE 10 2013 102 477 A1 and DE 10 2007 054 801 A1.
[0004] Against this background, the object of the invention is to provide a device that further develops the state of the art.
[0005] The problem is solved by a position determination method with the features of claim 1 and by a position determination system with the features of claim 4. Advantageous embodiments of the invention are the subject of dependent claims.
[0006] According to the first subject matter of the invention, a position determination method for determining rotational and translational movements of a control element is provided by means of a position determination system.
[0007] The position determination system has a rotation axis, whereby the control element can only be rotated around the rotation axis in a basic position that is concentric to the rotation axis.
[0008] The control element can be moved in a first plane at a fixed rotation angle perpendicular to the axis of rotation.
[0009] The position determination system includes a transmitter, a magnetic field sensor, and an evaluation unit, with the transmitter being attached to the control element.
[0010] In one alternative, the transmitter includes a permanent magnet.
[0011] In a second alternative, the transmitter is ferromagnetic, with the magnetic field sensor comprising a backbiased permanent magnet.
[0012] The transmitter generates a first magnetic field component and a second magnetic field component perpendicular to the first magnetic field component, with the first magnetic field component and the second magnetic field component lying in a measurement plane of the magnetic field sensor.
[0013] The first magnetic field component and the second magnetic field component are determined using the magnetic field sensor, and a signal vector is determined from the first magnetic field component and the second magnetic field component using the evaluation unit.
[0014] The evaluation unit determines the length of the signal vector and compares it with a reference value to determine a deviation or a match.
[0015] If there is a match, a rotation angle of the control element around the axis of rotation is determined based on the first magnetic field component and the second magnetic field component, and if there is a discrepancy, a two-dimensional position of the control element in the first plane is determined based on the signal vector.
[0016] According to the second item, a position determination system is provided for detecting rotational and translational movements of a control element.
[0017] The position determination system has a rotation axis, whereby the control element can only be rotated around the rotation axis in a basic position that is concentric to the rotation axis.
[0018] With a fixed rotation angle, the control element can be moved perpendicular to the axis of rotation in a first plane.
[0019] The position determination system includes a transmitter, a magnetic field sensor, and an evaluation unit, with the transmitter being attached to the control element.
[0020] In one alternative, the transmitter includes a permanent magnet.
[0021] In a second alternative, the transmitter is ferromagnetic and the magnetic field sensor includes a backbiased permanent magnet.
[0022] The transmitter generates a first magnetic field component and a second magnetic field component perpendicular to the first magnetic field component, with the first magnetic field component and the second magnetic field component lying in a measurement plane of the magnetic field sensor.
[0023] The magnetic field sensor is arranged in such a way that the axis of rotation penetrates the magnetic field sensor.
[0024] The magnetic field sensor is designed to determine at least one first magnetic field component running perpendicular to the axis of rotation and at least one second magnetic field component running perpendicular to the axis of rotation and perpendicular to the first magnetic field component.
[0025] The magnetic field sensor is arranged at a distance from the encoder in a direction extending along the axis of rotation. Furthermore, it is understood that preferably only the encoder is movable, i.e., the magnetic field sensor is always fixed in position.
[0026] It is understood that the first magnetic field component and the second magnetic field component represent two components of a vector, and the initial position is characterized in particular by the fact that the two components of the vector have predetermined values. Preferably, the magnitude of the vector in the initial position is constant and greater than zero. In other words, the magnitude of the vector is independent of the angle of rotation and constant along a circular line around the axis of rotation.
[0027] It should be noted that in the second alternative, the term "backbias" refers to a permanent magnet positioned below the magnetic field sensor. The term "below" here denotes the side of the magnetic field sensor facing away from the transmitter.
[0028] It is understood that either rotational or translational movements are possible in this case. In other words, the control element can be rotated clockwise or counterclockwise around its own axis of rotation in a neutral position. However, if a translational movement is performed, a rotational movement is impossible.
[0029] An advantage of the device according to the invention is that, with a two-dimensional magnetic field sensor, i.e., with a magnetic field sensor that detects at least the first and second magnetic field components, both translational and rotational positions can be determined easily, cost-effectively, and reliably. It is understood here that the distance between the encoder and the magnetic field sensor along the axis of rotation in the home position is known.
[0030] In a further development, the control element assumes only predetermined rotational angular positions around the axis of rotation. Preferably, a complete rotation of 360° includes several detents. Preferably, six, twelve, or eighteen detents are provided.
[0031] In one embodiment, a value for the first magnetic field component and a value for the second magnetic field component are stored in a table for each predetermined rotation angle position.
[0032] It should be noted that the positioning system is designed to execute the procedure for determining the position.
[0033] In one further development, the sensor is designed as a permanent magnet with a center of mass and a main magnetization direction. Preferably, the axis of rotation penetrates the center of mass of the permanent magnet, wherein the main magnetization direction and the axis of rotation enclose an angle greater than 0°.
[0034] In a further training, the center of mass of the permanent magnet is arranged at a distance from the axis of rotation.
[0035] In one embodiment, the encoder and the magnetic field sensor are spaced apart from each other in a projection along the axis of rotation.
[0036] In one embodiment, the magnetic field sensor is arranged concentrically to the axis of rotation.
[0037] In another embodiment, the magnetic field sensor is designed as a Hall sensor or as a magnetoresistive sensor.
[0038] In a further training course, the magnetic field sensor is monolithically integrated with the evaluation unit on a semiconductor body.
[0039] In another training course, the magnetic field sensor is designed as a 2D sensor.
[0040] In one embodiment, the permanent magnet is predominantly or completely axially magnetized.
[0041] In a further development, the first magnetic field component and the second magnetic field component in the measurement plane of the magnetic field sensor are different from zero for all positions.
[0042] The invention is explained in more detail below with reference to the drawings. Similar parts are labelled with identical designations. The illustrated embodiments are highly schematic; that is, the distances and the lateral and vertical extents are not to scale and, unless otherwise indicated, do not exhibit any derivable geometric relationships to one another. The drawings show that Fig. 1 a cross-sectional view of a first embodiment according to the invention, Fig. 2 a cross-sectional view of a second embodiment according to the invention Fig. 3 a cross-sectional view of a third embodiment according to the invention, Fig. 4 a vector representation of the magnetic field components.
[0043] The illustration of Fig. Figure 1 shows a view of a first embodiment, position determination system PS for detecting rotary and translational movements of a control element BD.
[0044] The PS position determination system has a rotary axis D, whereby the control element BD can only be rotated around the rotary axis D in a basic position aligned concentrically to the rotary axis D.
[0045] However, with a fixed rotation angle, the control element BD can be moved perpendicular to the axis of rotation in a first plane, i.e. in an x-direction as well as in a y-direction.
[0046] In other words, with the present control element BD, either rotary or translational movements are possible, i.e., the control element BD can be rotated arbitrarily clockwise or counterclockwise around its own axis of rotation in a basic position, but if a translational movement is performed, a rotary movement is excluded.
[0047] The PS position determination system comprises a permanent magnet PM as an encoder, a magnetic field sensor S1 mounted on a carrier TR, and an evaluation unit (not shown). The permanent magnet PM is mounted on the control element BD concentrically to the axis of rotation D. The permanent magnet PM has a magnetization direction M. The magnetization direction M is at an angle to the axis of rotation D; in other words, the magnetization direction M is predominantly, but not exclusively, axial.
[0048] By means of the encoder, a first magnetic field component and a second magnetic field component perpendicular to the first magnetic field component are generated in a measuring plane of the 2D magnetic field sensor S1.
[0049] The magnetic field sensor S1 is arranged at a distance from the encoder in a direction extending along the axis of rotation such that the axis of rotation D preferably penetrates the magnetic field sensor S1 at its center of gravity.
[0050] It is understood that the first and second magnetic field components represent two components of a vector, and the initial position is characterized in particular by the fact that the two components of the vector have predetermined values. In this initial position, the magnitude of the vector is constant and greater than zero. In other words, the magnitude of the vector is independent of the angle of rotation and constant along a circular line around the axis of rotation.
[0051] In the illustration of the Fig. Figure 2 shows a cross-sectional view of a second embodiment according to the invention. The following only highlights the differences compared to the illustration of the Fig. 1 explained.
[0052] The permanent magnet PM is mounted on the control element BD non-concentrically and preferably at a distance from the axis of rotation D. The permanent magnet PM has a predominantly (not shown) or exclusively axial magnetization direction M.
[0053] In the illustration of the Fig. Figure 3 shows a cross-sectional view of a third embodiment according to the invention. The following only highlights the differences compared to the illustration of the Fig. 1 or Fig. 2 explained.
[0054] The permanent magnet PM is mounted in a so-called "back-bias" arrangement below the magnetic field sensor S1, concentric to the axis of rotation D.
[0055] In this case, the magnetic field sensor S1 is arranged below the support TR.
[0056] Preferably, the permanent magnet PM has a predominantly axial magnetization direction M - not shown - or an exclusively axial magnetization direction M - not shown.
[0057] The encoder on the control element BD is designed as a ferromagnetic part and changes the size of the two magnetic field components in the measuring plane of the magnetic field sensor S1 during a rotational or translational movement.
[0058] It should be noted that in the second alternative, the term "backbias" refers to a permanent magnet positioned below the magnetic field sensor. The term "below" here denotes the side of the magnetic field sensor facing away from the transmitter.
[0059] In the illustration of the Fig.Figure 4 shows a vector representation of the magnetic field components for the preceding embodiments. For clarity, the individual components of the device are not shown.
[0060] In the basic position GP, the magnitude of the two magnetic field components, i.e., the first magnetic field component and the second magnetic field component, is constant and greater than zero along a circular solid line formed concentric to the axis of rotation D.
[0061] In a positive x-direction and a positive y-direction shifted position VP of the encoder, the values of the two magnetic field components assume the values along the dashed line, depending on the initial rotation angle position before the translational movement.
Claims
[1] Position determination method for determining rotational and translational movements of an operating element (BD) using a position determination system (PS), wherein - the positioning system (PS) has a rotational axis (D), - the control element (BD) is rotatable around the axis of rotation (D) only in a basic position (GP) aligned concentrically to the axis of rotation (D), - the control element (BD) is movable in a first plane at a fixed rotation angle perpendicular to the axis of rotation (D), - the position determination system (PS) includes a transmitter and a magnetic field sensor (S1) and an evaluation unit, - the transmitter is attached to the control element (BD), - in a first alternative, the transmitter includes a permanent magnet (PM), - by means of the transmitter a first magnetic field component and a second magnetic field component perpendicular to the first magnetic field component is generated, wherein the first magnetic field component and the second magnetic field component lie in a measuring plane of the magnetic field sensor (S1), - the first magnetic field component and the second magnetic field component are determined using the magnetic field sensor (S1), - a signal vector is determined from the first magnetic field component and the second magnetic field component using the evaluation unit, characterized by , that - in a second alternative the transmitter is ferromagnetic and the magnetic field sensor (S1) includes a backbiased permanent magnet (PM), - the evaluation unit determines the length of the signal vector and compares it with a reference value to determine a deviation or a match, - if the first magnetic field component and the second magnetic field component match, a rotation angle of the control element (BD) about the axis of rotation (D) is determined, and - in case of deviation, a two-dimensional position of the control element (BD) in the first plane is determined based on the signal vector. [2] Position determination method according to claim 1, characterized by , that the control element (BD) assumes only predetermined rotational angle positions around the axis of rotation (D). [3] Position determination method according to claim 2, characterized by , that for each predetermined rotation angle position, a value for the first magnetic field component and a value for the second magnetic field component are stored in a table. [4] Position determination system (PS) for detecting rotational and translational movements of a control element (BD), wherein - the positioning system (PS) has a rotational axis (D), - the control element (BD) is rotatable around the axis of rotation (D) only in a basic position (GP) aligned concentrically to the axis of rotation (D), - the control element (BD) is movable in a first plane at a fixed rotation angle perpendicular to the axis of rotation (D), - the position determination system (PS) includes a transmitter and a magnetic field sensor (S1) and an evaluation unit, - the transmitter is attached to the control element (BD), - in a first alternative, the transmitter comprises a permanent magnet (PM), - in a second alternative the transmitter is ferromagnetic and the magnetic field sensor (S1) includes a backbiased permanent magnet (PM), - the transmitter generates a first magnetic field component and a second magnetic field component perpendicular to the first magnetic field component, wherein the first magnetic field component and the second magnetic field component lie in a measurement plane of the magnetic field sensor (S1), - the magnetic field sensor (S1) is arranged such that the axis of rotation (D) penetrates the magnetic field sensor (S1), - the magnetic field sensor (S1) is designed to determine at least one first magnetic field component perpendicular to the axis of rotation (D) and at least one second magnetic field component perpendicular to the axis of rotation (D) and perpendicular to the first magnetic field component, - the magnetic field sensor (S1) is arranged at a distance from the encoder in a direction extending along the axis of rotation (D) and - the position determination system (PS) is designed to perform the method according to any one of claims 1 to 3. [5] Position determination system (PS) according to claim 4, characterized by that the transmitter is designed as a permanent magnet (PM) with a center of mass and a main magnetization direction. [6] Position determination system (PS) according to claim 5, characterized by , that the axis of rotation (D) penetrates the center of mass of the permanent magnet (PM) and that the main magnetization direction and the axis of rotation (D) enclose an angle greater than 0°. [7] Position determination system (PS) according to claim 5, characterized by , that the center of mass of the permanent magnet (PM) is arranged at a distance from the axis of rotation (D). [8] Position determination system (PS) according to any one of claims 4 to 7, characterized by , that the magnetic field sensor (S1) is arranged concentrically to the axis of rotation (D). [9] Position determination system (PS) according to any one of claims 4 to 8, characterized by, that the magnetic field sensor (S1) is designed as a Hall sensor or as a magnetoresistive sensor. [10] Position determination system (PS) according to any one of claims 4 to 9, characterized by , that the magnetic field sensor (S1) is monolithically integrated with the evaluation unit on a semiconductor body. [11] Position determination system (PS) according to any one of claims 4 to 10, characterized by , that the magnetic field sensor (S1) is designed as a 2D sensor. [12] Position determination system (PS) according to any one of claims 4 to 11, characterized by , that the permanent magnet (PM) is axially magnetized. [13] Position determination system (PS) according to any one of claims 4 to 12, characterized by , that the first magnetic field component and the second magnetic field component in the measurement plane of the magnetic field sensor (S1) are different from zero.