JP2024031954A - Inductive linear displacement sensor device and method for determining the position of a moving object - Google Patents

Abstract

An inductive linear displacement sensor device for determining the position of a moving object, the measurement sensing device comprising a coupling element arranged on the moving object and a circuit support having an excitation structure and a receiving structure. An inductive linear displacement sensor device is provided. An excitation structure (14) is coupled to an oscillator circuit, the oscillator circuit inputs a periodic alternating signal to the excitation structure (14), and a coupling element (3) connects the excitation structure (14) and the reception structure (16). The air gap LS between the coupling element 3 and the receiving structure 16 changes between the starting position SP and the target position ZP along the movement path BB of the coupling element 3, The evaluation and control unit 18 evaluates the measurement signals MS1, MS2 in the receiving structure 16 and changes the amplitude of the measurement signals MS1, MS2 in the movement path BB of the coupling element 3. and is configured to determine the absolute angular position of the coupling element 3 and the mobile body. [Selection diagram] Figure 1

Description

The present invention relates to an inductive linear displacement sensor device for determining the position of a moving object. The subject of the invention is also a method for determining the position of a moving body, which can be implemented with such an inductive linear displacement sensor device.

An inductive displacement sensor is known from DE 102015206500 A1, which includes a planar primary coil for generating a magnetic field, and a planar primary coil for generating a magnetic field. The system includes a coil system having two planar secondary coils arranged to sense the position of a target, the target being movable along the secondary coils. The secondary coils each have an intersection. In this case, two identical secondary coils are arranged spatially separated from each other, and the intersection of the respective secondary coils is oriented parallel to the direction of movement of the target.

An inductive position sensor is known from German patent application 602004006168 (DE 602004006168 T2), which comprises at least one flat substrate on which a transmitting antenna and a receiving antenna are formed; an intermediately disposed coupling element configured to move relative to at least one flat substrate along a measurement direction transverse to the flat substrate. Depending on the position of the intermediately arranged coupling element along the measuring direction, the electromagnetic coupling between the transmitting antenna and the receiving antenna varies, and at least the transmitting antenna or the receiving antenna has a first axis centered on the first axis. and a second coil centered on a second axis that is transverse to the first axis.

German Patent Application No. 102015206500 (DE102015206500A1) Translation of German patent application No. 602004006168 (DE602004006168T2)

DISCLOSURE OF THE INVENTION An inductive linear displacement sensor device having the features of independent claim 1 provides an inductive linear displacement sensor device for determining the absolute position of a mobile body moving along a travel path, on which an electrically conductive coupling element is arranged, of at least one receiving structure. The increased periodicity has the advantage that it can be easily determined from at least two induced measurement signals. Typically, the at least one receiving structure is configured such that a plurality of measurement signal periods occur over the measurement range. This results in higher signal resolution and thus a smaller deviation in the identified position of the moving object. In this case, it can be considered a disadvantage that the absolute position of the mobile body can no longer be determined from the measurement signal due to the resulting ambiguity. The air gap between the coupling element and the at least one receiving structure varies over the travel path of the mobile body, thereby determining the absolute angular position from the measured signal at an increased periodicity of the at least one receiving structure. becomes possible. This is because a variable air gap over the measurement range affects at least two measurement signals in the same way. The essential idea of the invention lies in the modulation of the absolute position relative to the vector length or amplitude of the vector determined from at least two measurement signals, caused by a variable air gap.

Embodiments of the present invention provide an inductive linear displacement sensor device for determining the position of a moving body, comprising: an electrically conductive coupling element disposed on the moving body; at least one excitation structure and at least one receiving structure; an inductive linear displacement sensor device comprising: at least one measurement detection device including at least one circuit support having a structure; The at least one excitation structure is coupled to at least one oscillator circuit, and the at least one oscillator circuit inputs a periodic alternating signal to the at least one excitation structure during operation. The coupling element affects inductive coupling between the at least one excitation structure and the at least one reception structure. In this case, the air gap between the coupling element and the at least one receiving structure varies between the starting position and the target position along the movement path of the coupling element, resulting in an amplitude change of the at least two induced measurement signals. cause. At least one evaluation and control unit evaluates the at least two measurement signals induced in the at least one receiving structure and modulates the amplitudes of the at least two measurement signals induced over the travel path of the electrically conductive coupling element. The device is configured to determine a current absolute angular position representing a current position of the coupling element and the mobile body, taking into account further information about the coupling element and the moving object.

Furthermore, a method is proposed for determining the position of a mobile body, which can be implemented with such an inductive linear displacement sensor device. In this case, during operation, a periodic alternating signal is input to the at least one excitation structure. An electrically conductive coupling element is connected to the moving body and forms an inductive coupling between the at least one excitation structure and the at least one reception structure. At least two different measurement signals are induced via the at least one receiving structure and are provided as approximately trigonometric signals having a periodicity of each of the at least two periodicities. On the basis of the at least two measurement signals and further information modulated on the amplitudes of the at least two measurement signals, a current absolute angular position is determined which represents the absolute position of the coupling element and of the mobile body.

An evaluation and control unit in this specification can be understood as an electrical assembly or circuit that processes or processes or evaluates the detected sensor signals. Preferably, the evaluation and control unit can be constructed as an ASIC module (ASIC: application-specific integrated circuit). The evaluation and control unit can have at least one interface that can be configured by hardware and/or software. If implemented in hardware, the interface may be part of an ASIC module, for example. However, it is also possible for the interface to be a separate integrated circuit or to consist at least partially of discrete components. If implemented in software, the interface can be, for example, a software module mounted on a microcontroller adjacent to other software modules.

An "excitation structure" in the following can be understood as a transmission coil with a predetermined number of windings, which emits an alternating signal input by at least one oscillator circuit.

By means of the measures and developments specified in the dependent claim, an inductive linear displacement sensor device for determining the position of a moving body as defined in independent claim 1 and as defined in independent claim 8 , it is possible to advantageously improve the method for locating a mobile object.

It is particularly advantageous that at least one receiving structure can have at least two receiving coils. In this case, the at least two receiver coils may each have one periodically repeating loop structure, the geometry of the loop structure being such that the induced at least two measurement signals are approximately trigonometric. It is configured so that it is generated as a signal.

In an advantageous embodiment of the inductive linear displacement sensor device, the at least one receiving structure can have exactly two receiving coils, the exactly two receiving coils having at least two periodic Each of them has one periodicity. In this case, the first receive coil may form a sine channel and the second receive coil may form a cosine channel. The at least one evaluation and control unit is configurable to determine a corresponding angle value from the first measurement signal of the sine channel and the second measurement signal of the cosine channel by an arctangent function, and The current position of the connected element is based on the angle value. Alternatively, the at least one receiving structure may have at least three receiving coils, each of the at least three receiving coils having a periodicity of one of the at least two periodicities, and , forming a polymorphic system. In this case, the at least one evaluation and control unit can be configured to carry out a suitable phase transformation of the measurement signal of the polyphase system and to determine the corresponding angular value using an arctangent function. The current position of the connected element in is based on the angle value.

In a further advantageous embodiment of the inductive linear displacement sensor device, the at least one evaluation and control unit determines the current absolute position of the coupling element on the movement path by the determined angular value and the at least two guided and information regarding changing amplitudes of the measurement signal.

In a further advantageous embodiment of the inductive linear displacement sensor device, the evaluation and control unit is further configured to take into account the current amplification factor in determining the current absolute position of the coupling element in the automatic amplification control. Configurable. Such automatic amplification control can be used, for example, to achieve the best possible signal-to-noise ratio at the output of the at least one evaluation and control unit.

In an advantageous embodiment of the method, in order to determine the absolute angular position of the coupling element and of the mobile body, a signal is formed from the induced measurement signal or from a signal converted from the induced measurement signal. The length and angle of the vector can be identified and evaluated.

An embodiment of the invention is shown in the drawing and is explained in more detail in the following description. Other embodiments of the invention are shown in the drawings and are explained in more detail in the following description. In the drawings, components or elements that perform the same or similar functions are provided with the same reference symbols.

1 is a schematic perspective view of an embodiment of an inductive linear displacement sensor device according to the invention for determining the position of a moving object; FIG. 2 is a schematic characteristic curve diagram of two measurement signals of the inductive linear displacement sensor device according to the invention of FIG. 1; FIG. 3 is a schematic illustration of a Lissajous figure formed from the two measurement signals of FIG. 2; FIG. 1 is a schematic flowchart of an embodiment of a method according to the invention for locating a mobile object;

EMBODIMENTS OF THE INVENTION As can be seen from FIGS. 1 and 2, the illustrated embodiment of an inductive linear displacement sensor device 1 according to the invention for determining the position of a moving body is shown in FIG. and at least one measurement value detection device 10, which includes at least one circuit carrier 12 with at least one excitation structure 14 and at least one reception structure 16. . The at least one excitation structure 14 is coupled to at least one oscillator circuit (not shown), the at least one oscillator circuit inputting a periodic alternating signal to the at least one excitation structure 14 during operation. . The coupling element 3 effects an inductive coupling between at least one excitation structure 14 and at least one reception structure 16. The air gap LS between the coupling element 3 and the at least one receiving structure 16 varies between a starting position SP and a target position ZP along the movement path BB of the coupling element 3, and at least two guided measurements are performed. This causes amplitude changes in signals MS1 and MS2. At least one evaluation and control unit evaluates the at least two measurement signals MS1, MS2 induced in the at least one receiving structure 16 and determines the amplitude of the at least two measurement signals MS1, MS2 induced in the conductive structure. Taking into account the further information modulating over the movement path BB of the coupling element 3, a current absolute angular position is determined which represents the current position of the coupling element 3 and the mobile body.

As can be further seen from FIG. 1, the illustrated embodiment of the inductive linear displacement sensor device 1 consists of a single receiver with two receiver coils 16A, 16B, integrated in a transparently illustrated circuit carrier 12. A structure 16 is included. The two receiving coils 16A, 16B each have one periodically repeating loop structure 16.1A, 16.1B, 16.2A, 16.2B, which loop structures 16.1A, 16.1B, The geometry of 16.2A, 16.2B, as can be seen in FIG. 2, is configured such that the two induced measurement signals MS1, MS2 occur as approximately trigonometric signals. The circuit carrier 12 is formed as a multilayer printed circuit board 12A. As can be further seen from FIG. 1, the individual repeating loop structures 16.1A, 16.1B, 16.2A, 16.2B of the two receiving coils 16A, 16B each have a sinusoidal shape and a second The repeating loop structure 16.1B, 16.2B of the first receiver coil 16B is shifted by 90° with respect to the repeating loop structure 16.1A, 16.2A of the first receiver coil 16A. As can be further seen from FIG. 1, a plurality of sections of repeating loop structures 16.1A, 16.1B, 16.2A, 16.2B of the two receiver coils 16A, 16B are arranged in respective different layers of the circuit support 12. This makes it easy to avoid duplication. The sections of the repeating loop structures 16.1A, 16.1B, 16.2A, 16.2B, respectively arranged in different layers, are electrically interconnected via through-hole contacts 16.3. ing. Furthermore, the first receiver coil 16A has a reversal point, not shown in detail, at the target position ZP, which results in two opposite repeating loop structures 16.1A of the first receiver coil 16A, respectively. , 16.2A, a plurality of surfaces are formed in which magnetic fields each having a different direction are induced. In this case, the number of these plane pairs determines the periodicity of the first receiving coil 16A of the receiving structure 16. The second receiving coil 16B also has a reversal point, not shown in detail, at the target position ZP, thereby resulting in two opposite repeating loop structures 16.1B, 16 of the second receiving coil 16B, respectively. .2B, a plurality of surfaces are formed in which magnetic fields each having a different orientation are induced. In this case, the number of these plane pairs determines the periodicity of the second receiving coil 16B of the receiving structure 16. In the illustrated embodiment, the two receive coils each have one of two periodicities. Furthermore, the first receiving coil 16A of the receiving structure 16 forms a sinusoidal channel providing the first measurement signal MS1. The second receiving coil 16B of the receiving structure 16 forms a cosine channel providing a second measurement signal MS2. In this case, the evaluation and control unit 18, which is configured as an ASIC module 18A, uses an arctangent function from the two measurement signals MS1, MS2 to determine the corresponding angular position of the coupling element 3 on the movement path BB. The current position is based on this angular position.

In an alternative embodiment, not shown, of the inductive linear displacement sensor device 1, the at least one receiving structure 16 has at least three receiving coils with a periodically repeating loop structure. At least three receive coils form a polyphase system. In this case, the corresponding evaluation and control unit 18 carries out a suitable phase transformation of the signals of the polyphase system, preferably using a Clark transformation, and extracts from the two transformed measurement signals MS1, MS2 using an arctangent function. , identify the corresponding angular position.

As can be further seen from FIG. 1, the coupling elements 3, 3A, 3B, which can also be referred to as targets, are arranged in a first position where the coupling element 3A has a first distance AA to the surface of the printed circuit board 12A and in a first position where the coupling element 3B has a first distance AA to the surface of the printed circuit board 12A. is at a second position having a second distance AB to the surface of printed circuit board 12A. This means that the air gap LS corresponds to a first spacing AA in the first illustrated position of the coupling element 3A and to a second spacing AB in the illustrated second position of the coupling element 3B. means. The height of the voltage induced in the receiving coils 16A, 16B depends on the air gap LS. For known linear displacement sensor devices, a constant air gap LS is typically selected to achieve a constant signal-to-noise ratio. Due to the non-parallel guiding of the coupling element 3 along the movement path B, the air gap LS is variable, which influences the induced voltage or the height or amplitude of the measurement signals MS1, MS2. The movement of the coupling element 3 along the movement path B over the entire measurement range results in the demodulated measurement signals MS1, MS2 of FIG. In the complex plane of FIG. 3, the measurement signals MS1, MS2 represent vectors VA, VB that move along the illustrated Lissajous diagram depending on the position of the coupling element 3 between the starting position SP and the target position ZP. In this case, the vector length is influenced by the air gap LS. FIG. 3 shows by way of example the vectors VA, VB for the two positions of the coupling elements 3, 3A, 3B shown in FIG. The target position ZP corresponds to the end of the measurement range with the smallest air gap LS and thus the largest signal amplitude. Similarly, the starting position SP corresponds to the end of the measurement range with the largest air gap LS and the smallest signal amplitude. Due to the periodicity of the two, it is not possible to estimate the absolute position from the electrical phase angles a and b. This is because the vectors VA and VB rotate twice over the entire measurement range. A unique mapping to the absolute position of the coupling element 3 is possible simply by considering the varying vector length caused by the variable air gap LS as additional information. This means that the evaluation and control unit 18 determines the current absolute position of the coupling element 3 on the movement path BB with respect to the determined angular value and the changing amplitude of the at least two induced measurement signals MS1, MS2. It means to identify based on information. In order to determine the absolute angular position or absolute position of the coupling element 3 and of the moving body, the evaluation and control unit generates or converts the derived measurement signals MS1, MS2 from the derived measurement signals MS1, MS2. The lengths and angles a, b of the corresponding vectors VA, VB formed from the obtained signals are identified and evaluated.

In the illustrated embodiment of the inductive linear displacement sensor device 1, the evaluation and control unit 18 implements an automatic amplification control, whereby the current amplification is coefficients are taken into account.

As can further be seen from FIG. 4, the illustrated embodiment of the method 100 according to the invention for determining the position of a mobile body, which can be carried out by means of the above-described inductive linear displacement sensor device 1, periodically The method includes a step S100 in which an alternating signal is input to at least one excitation structure 14. In this case, an electrically conductive coupling element 3 is connected to the mobile body and forms an inductive coupling between the at least one excitation structure 14 and the at least one reception structure 16. In step S110, at least two different measurement signals MS1, MS2 are induced via the at least one receiving structure 16, and in step S120, approximately Provided as a trigonometric signal. In step S130, on the basis of the at least two measurement signals MS1, MS2 and further information modulated on the amplitudes of the at least two measurement signals MS1, MS2, a current The absolute angular position of is determined.

In the illustrated embodiment of the method 100, in step S130, the derived measurement signals MS1, MS2 are formed or derived from the derived measurement signals MS1, MS2 in order to determine the absolute angular position of the coupling element 3 and the mobile body. The lengths and angles a, b of the vectors VA, VB formed from the signals transformed from MS1, MS2 are determined and evaluated.

As can be further seen from FIG. 1, the coupling elements 3, 3A, 3B, which can also be referred to as targets, are arranged in a first position where the coupling element 3A has a first distance AA to the surface of the printed circuit board 12A and in a first position where the coupling element 3B has a first distance AA to the surface of the printed circuit board 12A. is at a second position having a second distance AB to the surface of printed circuit board 12A. This means that the air gap LS corresponds to a first spacing AA in the first illustrated position of the coupling element 3A and to a second spacing AB in the illustrated second position of the coupling element 3B. means. The height of the voltage induced in the receiving coils 16A, 16B depends on the air gap LS. For known linear displacement sensor devices, a constant air gap LS is typically selected to achieve a constant signal-to-noise ratio. Due to the non-parallel guiding of the coupling element 3 along the movement path B B , the air gap LS is variable, which influences the induced voltage or the height or amplitude of the measurement signals MS1, MS2. The movement of the coupling element 3 along the movement path B B over the entire measurement range results in the demodulated measurement signals MS1, MS2 of FIG. In the complex plane of FIG. 3, the measurement signals MS1, MS2 represent vectors VA, VB that move along the illustrated Lissajous diagram depending on the position of the coupling element 3 between the starting position SP and the target position ZP. In this case, the vector length is influenced by the air gap LS. FIG. 3 shows by way of example the vectors VA, VB for the two positions of the coupling elements 3, 3A, 3B shown in FIG. The target position ZP corresponds to the end of the measurement range with the smallest air gap LS and thus the largest signal amplitude. Similarly, the starting position SP corresponds to the end of the measurement range with the largest air gap LS and the smallest signal amplitude. Due to the periodicity of the two, it is not possible to estimate the absolute position from the electrical phase angles a and b. This is because the vectors VA and VB rotate twice over the entire measurement range. A unique mapping to the absolute position of the coupling element 3 is possible simply by considering the varying vector length caused by the variable air gap LS as additional information. This means that the evaluation and control unit 18 determines the current absolute position of the coupling element 3 on the movement path BB with respect to the determined angular value and the changing amplitude of the at least two induced measurement signals MS1, MS2. This means identifying based on information. In order to determine the absolute angular position or absolute position of the coupling element 3 and the moving body, the evaluation and control unit generates or converts the derived measurement signals MS1, MS2 from the derived measurement signals MS1, MS2. The lengths and angles a, b of the corresponding vectors VA, VB formed from the obtained signals are identified and evaluated.

Claims (9)

An inductive linear displacement sensor device (1) for determining the position of a moving body, comprising an electrically conductive coupling element (3) arranged on said moving body, at least one excitation structure (14) and at least one In an inductive linear displacement sensor device (1) comprising at least one measurement value detection device (10) comprising at least one circuit carrier (12) with one receiving structure (16),
The at least one excitation structure (14) is coupled to at least one oscillator circuit, the at least one oscillator circuit transmitting a periodic alternating signal to the at least one excitation structure (14) during operation. and enter
said coupling element (3) effects an inductive coupling between said at least one excitation structure (14) and said at least one reception structure (16);
An air gap (LS) between the coupling element (3) and the at least one receiving structure (16) provides a starting position (SP) and a target position along the movement path (BB) of the coupling element (3). (ZP) causing an amplitude change of at least two induced measurement signals (MS1, MS2);
At least one evaluation and control unit (18)
evaluating at least two measurement signals (MS1, MS2) induced in said at least one receiving structure (16);
modulating the amplitude of the at least two induced measurement signals (MS1, MS2) over the travel path (BB) of the electrically conductive coupling element (3), taking into account further information on the coupling element (3); and configured to identify a current absolute angular position representing the current position of the mobile object.
Inductive linear displacement sensor device (1). the at least one receiving structure (16) having at least two receiving coils (16A, 16B);
Inductive linear displacement sensor device (1) according to claim 1. the at least two receiving coils (16A, 16B) each have one periodically repeating loop structure (16.1A, 16.1B, 16.2A, 16.2B);
The geometry of the loop structure (16.1A, 16.1B, 16.2A, 16.2B) is such that the at least two induced measurement signals (MS1, MS2) occur as approximately trigonometric signals. It is configured as follows.
Inductive linear displacement sensor device (1) according to claim 2. The at least one receiving structure (16) has two receiving coils (16A, 16B), each of the two receiving coils (16A, 16B) having a periodicity of at least two periodicities. has
The first receiver coil (16A) forms a sine channel, the second receiver coil (16B) forms a cosine channel,
The at least one evaluation and control unit (18) determines a corresponding angle value from the first measurement signal (MS1) of the sine channel and the second measurement signal (MS2) of the cosine channel by an arctangent function. the current position of the coupling element (3) on the movement path (BB) is based on the angle value;
Inductive linear displacement sensor device (1) according to claim 3. The at least one receiving structure (16) has at least three receiving coils, each of the at least three receiving coils having a periodicity of at least two of the periodicities and having a polyphasic form a system,
The at least one evaluation and control unit (18) is configured to carry out a suitable phase transformation of the measurement signal of the polyphase system and to determine the corresponding angle value using an arctangent function, the current position of said coupling element (3) on the movement path (BB) is based on said angle value;
Inductive linear displacement sensor device (1) according to claim 3. The at least one evaluation and control unit (18) determines the current absolute position of the coupling element (3) on the movement path (BB) by the determined angular value and by the derived at least two measurements. and information regarding changing amplitudes of the signals (MS1, MS2).
Inductive linear displacement sensor device (1) according to claim 4 or 5. The evaluation and control unit (18) is further configured to take into account the current amplification factor when determining the current absolute position of the coupling element (3) in automatic amplification control.
Inductive linear displacement sensor device (1) according to any one of claims 4 to 6. A method (100) for determining the position of a mobile body, implementable by an inductive linear displacement sensor device (1) according to any one of claims 1 to 7, comprising:
In operation, a periodic alternating signal is input to the at least one excitation structure (14);
an electrically conductive coupling element (3) is connected to the mobile body and forms an inductive coupling between the at least one excitation structure (14) and the at least one reception structure (16);
At least two different measurement signals (MS1, MS2) are induced via said at least one receiving structure (16), approximately trigonometric, each having a periodicity of one of at least two periodicities. provided as a signal,
Based on the at least two measurement signals (MS1, MS2) and further information modulated on the amplitude of the at least two measurement signals (MS1, MS2), the coupling element (3) and the a current absolute angular position representing the absolute position is determined;
Method (100). is formed from the derived measurement signals (MS1, MS2) or from the derived measurement signals (MS1, MS2) in order to determine the absolute angular position of the coupling element (3) and of the mobile body. The length and angle (a, b) of the vector (VA, VB) formed from the transformed signal are identified and evaluated;
The method (100) of claim 8.