EP2208026A2

EP2208026A2 - Measuring method and measuring instrument for inductively determining angles and/or positions

Info

Publication number: EP2208026A2
Application number: EP08847579A
Authority: EP
Inventors: Gerd Reime
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-11-09
Filing date: 2008-11-05
Publication date: 2010-07-21
Also published as: WO2009059750A2; WO2009059750A3; DE102007053881A1; DE102007053881B4

Abstract

In a measuring method and a measuring instrument for inductively determining the angle and/or position of at least two parts (B1, B2) relative to one another, two transmission coils (11, 12) which are arranged at an angle from each other and generate a magnetic field as a result of a current are associated with one part (B1), and a reception coil (13) in which a current is induced as a result of the magnetic field generated by the transmission coils (11, 12) is associated with other part (B2). The magnetic field is generated as a result of a current that flows through the transmission coils (11, 12) and is clocked by means of a clock controller (14). A magnetic field is thus induced in the reception coil (13) and is converted into an electrical signal (41) which is then assigned to the transmission coils (11, 12). The assigned signals are fed to regulators (17, 18) to generate a comparative value (70) at the output (16c) of a comparator (16) in order to regulate the current flowing into the transmission coils (11, 12). The currents through the transmission coils are regulated such that the amplitude values (41 A, 41 B) of the electrical signal (41) become identical at the inputs (16a, 16b) of the comparator (16), said amplitude values (41 A, 41 B) being associated with the transmission coils. The ratio between the current values fed to the transmission coils (11, 12) is acquired as a measure for determining the position and/or angle of the parts (B1, B2) relative to one another.

Description

Measuring method and measuring device for inductive angle and / or

location

description

Related to related applications

The present application claims the priority of German Patent Application 10 2007 053 881.4, filed on 09.11.2007, the disclosure content of which is expressly also made the subject of the present application.

Field of the invention

The invention relates to a measuring method and a measuring device for inductive angle and / or position determination of at least two components to each other according to the preamble of claim 1 and 9 respectively.

State of the art

When measuring components to each other can not always be measured to a stationary reference point. This is z. B. in the measurement of Luftbalgfederungen in trucks the case. For such and similar purposes, it is necessary to measure different points relative to each other. This has hitherto been done e.g. by hand with optical aids by positioning two points relative to each other. However, the optical systems have the disadvantage in this purpose that they are subject to the same pollution, as the Radfederung itself.

For measuring dynamic changes, the HALIOS process has already been described in EP 0 706 648 B1. This method is suitable for optical as well as for inductive purposes. The transmitters are operated by a clock generator time-wise and alternately. The signal regulated in the amplitude of at least one path acts on the receiver in such a way that a reception signal signal without isochronous signal components. The received signal of the receiver is fed to a synchronous demodulator, which in turn decomposes the received signal into the signal components corresponding to at least two transmitters. These are compared in a comparator with each other, wherein in the idle state without foreign influences a signal corresponding to a zero state arises.

If no signal corresponding to this zero state is present at the output of the comparator, the power supplied to the transmitters is regulated until this state is reached. This evaluates the control value at the output of the comparator, which is also a measure of the deviation from the zero state.

Object of the invention

On the basis of this prior art, the object of the present invention is to provide an improved measuring method and an improved measuring device for the inductive angle determination and / or position determination, which are cost-effective and as far as possible insensitive to environmental influences.

This object is achieved by a measuring method having the features of claim 1 and by a measuring device having the features of claim 9.

The invention makes use of the principle that in the known HALIOS method it is also measured whether an alternating field is present in the receiving coil as a result of the mutually operated transmitting coils. This alternating field is compensated to zero by the controlled introduction of current into the transmitting coils or the concomitant change in the magnetic field caused by the transmitting coils until the magnetic fields in the receiving coil caused by the current flowing in the coils cancel each other out. Up to this point in time, however, amplitude values which can be assigned to the transmitting coils are present from the two transmitting coils at the receiving coil, whereby the ratio of these amplitude values to one another does not depend on the magnitude of the amplitude. This ratio is also a measure of the angular and / or positional mung of the components to each other. This makes it possible to create a simple and extremely robust sensor unit even for harsh environmental conditions. The usual, working in a mechanically narrow range, fine mechanical devices such as rotary potentiometer or Hall generators omitted. The sensor units can be "coarsely" positioned at a great distance from each other without the need for a mechanical connection to one another Pollution or wetness do not affect the measurement In addition, the components of the sensor units can be positioned on a printed circuit board with conductor tracks and without further assembly Elements are used.

Any existing measuring range limits, which are determined by the minimum power limits of the driver powers for the transmitting coils, can be overcome by, if necessary, upon detecting the reaching of a limit, the current direction in the respective transmitting coil is changed. As a result, measuring range limits of up to 360 ° can be achieved.

Further advantages emerge from the subclaims and the following description.

Brief description of the figures

In the following the invention will be explained in more detail with reference to the attached figures. Show it:

1 is a block diagram of an electronics for performing the measuring method,

2 shows the arrangement of the coils in the relatively moving components,

2a-2d show the change of the amplitude values of all cycles in a measuring cycle over time at the areas A, B, C and FIG

-C at 0 ° or 180 °,

Fig. 3 shows the current signals for a transmission channel (the second channel is indicated by dashed lines). Detailed description of preferred embodiments

The invention will now be described by way of example with reference to the accompanying drawings. However, the embodiments are only examples that are not intended to limit the inventive concept to a particular arrangement. Before describing the invention in detail, it should be noted that it is not limited to the respective components of the device and the respective method steps, since these components and methods may vary. The terms used herein are intended only to describe particular embodiments and are not intended to be limiting. In addition, if singular or indefinite articles are used in the specification or claims, this also applies to the majority of these elements unless the overall context clearly makes otherwise clear.

1 shows a block diagram for a measuring method for inductive position and / or angle determination of at least two components B1, B2 relative to one another. At least two transmitting coils 11, 12 are assigned to one component B1, while at least one receiving coil 13 is assigned to the other component B2. As a result of a current which is passed through the transmitting coils 11, 12, and due to the magnetic fields generated thereby, a current in the receiving coil 13 is induced. The magnetic fields are in the receiving coil 13 as a result of the clock control 14, the alternately via the output 14a and the inverted output 14b the at least two transmitting coils 11, 12 clocked induced alternating field, so that the current in the receiving coil 13 with the clock of Clock control changes. The difference of the magnetic fields in the receiving coil is simultaneously position-dependent on the position and especially angular position of the transmitting coil to the receiving coil 13. The induced in the receiving coil 13 magnetic field that changes in movement of the transmitting coils 11, 12 relative to the receiving coil 13, passes over the one - Ganges 23a, 23a ^{1 of} the amplifier 23 via the output 23b as an electrical signal 41 to a synchronous demodulator D with sensitive amplitude comparator. There, the electrical signal via the switches S1, S2 the respective transmitting coils 11, 12 as amplitude value 41 A, 41 B assigned. Via the lines 60a, 60b and the Resistors R1, R2 and the associated integration elements C1, C2 pass the thus determined amplitude values to the inputs 16a, 16b of the comparator 16.

There, the associated amplitude values 41 A, 41 B of the electrical signal 41 are compared in order to generate a comparison value 70 at the output 16 c of the comparator. If there is a difference at the inputs 16a, 16b, this will be present as a control voltage at the output 16c. This comparison value 70 is supplied inversely via the lines 71, 74 to the input 17a and via the line 75 via the inverter 15 to the input 18a of regulators 17, 18 configured as phase-reversed control stages. These regulators 17, 18 are connected at their other inputs 17b, 17c and 18b, 18c to the outputs 14a, 14b of the clock controller 14. The controllers control via their outputs 17d, 18d via the lines 31, 32 on the one hand and 37, 36 on the other hand, the transmitting coils 11, 12 supplied control signal or regulated in the transmitting coil current, thereby extinguishing the induced in the receiving coil 13 of the transmitting coil alternating field. This leads to a time-variable regulation until the amplitude values 41 A, 41 B of the electrical signal 41 assigned to the transmission coils 11, 12 at the inputs 16a, 16b of the comparator 16 become the same. The transmitting coils 11, 12 may optionally be connected to the ground 39 via the line 38. This method is known per se as HALIOS method from EP 0 706 648 B1.

In order to determine the position and / or angle determination of the at least two components B1, B2 relative to one another, the ratio of the control values to one another, which are represented by the currents on the lines, is now considered. They are supplied via the lines 72, 73 to a microprocessor 80 which detects the ratio and outputs 94 as the value. These time-variable amplitude values, which are influenced by the regulators 17, 18, namely form the rotation or a movement of the components to be detected as a rotation relative to one another. They can be positioned "coarsely" and do not require a mechanical connection to each other, they do not affect the measurement due to dirt or moisture, and the arrangement is essentially based on HALIOS standard amplitude control with additional driver electronics that can be used as needed to reverse the phase , Preferably, two similar transmitting coils are used, but different coils may be used, if desired, as this may lead to correspondingly altered results. The transmitting coils 11, 12 are preferably arranged close to one another and can preferably be arranged orthogonally. Another angular arrangement is possible. In the embodiment of FIGS. 1, 2, the receiving coil 13 is located on the bisector of the transmitting coils 11, 12. This is not absolutely necessary, because in principle any other angular arrangement of the transmitting coils can be made to the receiving coil.

The coils can be designed as a printed version on a printed circuit board. In practice, for example, about 70 turns with 40mm PCB diameter have been proven for a range of over one meter. The transmitting coils and the receiving coil can be connected to corresponding resonance capacitors according to the possibly provided impedances Z1, Z2, e.g. may consist of resistors are provided that prevent unnecessary harmonics of the Halios Rectangular. Resonance formation in the receiving circuit simultaneously increases the sensitivity of the system. The whole system can also be operated with one sine beat.

Evaluation is e.g. the angle of rotation of the sensor units to each other, without the distance has an influence. Thus, with a fixed transmission arrangement with two transmitting coils 11, 12, which are tilted + 45 ° and -45 ° to the horizontal, the horizontal receiving coil 13 can be shifted in the distance, without the measured value changes. Movement possibilities lying in the sheet plane of FIG. 1 in the exemplary embodiment are indicated by the arrows 20, 21 in FIG. 1, wherein a movement in the direction of the arrow 20 only supplies a measured value, if at the same time a rotation with respect to the arrangement of the receiving coil 13 relative to the transmitting coils 11, 12 takes place.

The measured value lies in the described arrangement in the middle of the possible measured value range. A rotation of the components B1, B2, on the one hand the transmission len and on the other hand wear the receiving coil, leads to a corresponding positive or negative deviation. It does not matter whether a rotation takes place locally or whether one of the two arrangements is moved vertically, since this movement is equal to a rotational movement. In a 90 ° arrangement of the transmitting coils to each other is formed around this arrangement at each point in space a magnetic field with exactly 90 ° offset field lines due to the magnetic fields in the transmitting coils 11, 12th Areas outside the circle plane also contain the 90 ° offset field lines with an additional angle component. By appropriate rotation of the receiving coil, however, this angle component can be fully compensated.

The angular deviation of the transmitting or receiving unit is mapped in the amplitude values in the Halios system by an amplitude control. In the far field e.g. From about 10 cm of the electromagnetic transmitter, the amplitude change is approximately linear to the angle change. If the amplitude of a phase, as provided in the standard Halios method, is controlled from zero to the maximum power, an angle range of, for example, +/- 25 ° can be detected. In order to detect a range of +/- 45 °, therefore, the amplitude of the phase must be mirrored above zero in negative ranges, this is achieved by the fact that when controlling from the maximum value to zero and, for example, the phase 0 ° the value increases again from zero, but with 180 ° phase rotation. This is possible with the inductive solution in that the current direction in the coil can be changed.

The phase of the current of the at least two transmitting coils 11, 12 is thus rotated at the control limits of the current drivers for the transmitting coils 11, 12, which is determined by a power of zero. With opposite amplitude values 41 A, 41 B, the current direction is changed when an amplitude of zero is reached. This is shown in FIGS. 2a to 2d. In the case of A, a movement takes place along the line A. As shown in FIG. 2a, this leads to equal amplitude values 51, 52 at a phase of 0 and 180 °. However, if a rotation in the direction of the line B, the amplitude value 53 associated with the transmitting coil 12 decreases in Fig. 2b, so that the ratio of the amplitude values changes, which corresponds to a certain angular deviation. Another angle deviation from the line A in the direction of the line C. is now no longer representable, since the amplitude value 53 can not be further reduced. If one of the two electrical currents K1, K2 in FIG. 3 in the transmitter coil 11, 12 approaches zero, the phase can be rotated from zero with suitable driver electronics and thus the current direction can be changed, and the control goes through 180 ° ° rotated phase on. This is shown in FIG. When the currents are reduced, starting at a certain point at a phase of 0 °, only one signal with the value zero is obtained. If the relative rotation between the transmitting coil and the receiving coil continues in the same direction, the control is continued in the same direction, the current signal being rotated or inverted by 180 ° in the corresponding coil. The same applies to the current K2, which is shown in dashed lines in Fig. 3 for the sake of completeness and is mirrored only at the angle 0 °.

In an angular range of approximately 0 to +/- 25 °, both transmission phases of the transmission coils in the Halios method have 0 and 180 °, while they are equal in the angular range greater than +/- 25 °, ie both have either 0 ° or 180 ° , The phase inversion is achieved by a corresponding circuit arrangement, a phase mirror in addition to the Halios method. By switching the current direction in the transmitting coils in a further measuring cycle, an angle determination can be achieved from +/- 45 °, so that with a suitable evaluation of the currents, a total angle determination of 360 ° is possible.

For a three-dimensional angle or position determination, a further coil is arranged so that its main axis intersects with the main axes of the two existing transmitting coils. Preferably, the main axes of the transmitting coils form a Cartesian coordinate system, wherein the third transmitting coil is occupied by a further measuring phase.

It will be understood that this description is susceptible to various modifications, changes and adaptations, ranging from equivalents to the appended claims. LIST OF REFERENCE NUMBERS

11.12 transmission coil

13 receiver coil

14 clock control

14a, 14b output

15 inverters

16 comparators

16a, 16b entrance

16c output

17, 18 controls

17a, 17b, 17c entrance

18a, 18b, 18c entrance

17d, 18d output

20.21 arrow

23 amplifiers

23a, 23a 'entrances

23b output

31,32,36,37,38 pipe

39 mass

41 Electric signal

41A.41B Amplitude value

51, 52, 53, 54 amplitude value

6OA, 6OB pipe

70 comparative value

71 -75 line

80 microprocessor

94 value

B1. B2 component

R1. R2 resistance

C1. C2 integration elements

Z1.Z2 impedance

Claims

claims

1. Measuring method for inductive angle and / or position determination of at least two components (B1, B2) to one another, wherein the one component (B1) at least two angularly arranged mutually, as a result of a current magnetic field forming transmitter coils (11, 12) are assigned and wherein the other component (B2) is assigned at least one receiving coil (13) in which a current is induced as a result of the magnetic field built up by the transmitting coils (11, 12), with at least one clock control (14) for alternately clocked operation of the at least two transmitting coils (11, 12), with the steps

Establishing the magnetic field as a result of a clocked current flowing through the transmit coils (11, 12) due to the clock control (14), inducing a magnetic field in the receive coil (13) due to the magnetic fields produced by the current in the transmit coils and converting that in the receive coil (13) induced magnetic field into an electrical signal (41),

Assigning the amplitude values (41A, 41B) of the electrical signals (41) to the transmitting coils (11, 12),

Comparing the associated amplitude values (41A, 41B) of the electrical signal (41) to produce a comparison value (70) at the output (16c) of a comparator (16) for controlling the amplitude values of the current flowing into the transmitting coils (11, 12) by means of at least a regulator (17, 18), so that the amplitude values (41 A, 41 B) of the electrical signal (41) associated with the transmitting coils become the same at the inputs (16a, 16b) of the comparator (16), characterized by detecting the Ratio of the currents supplied to the transmitting coils (11, 12) to each other as a measure of the position and / or angle determination of the components (B1, B2) to each other.

2. Measuring method according to claim 1, characterized in that the phase of the current of the at least two transmitting coils at the control limits of Stromtrei- is reversed for the transmitting coils (11, 12) determined by a power of zero.

3. Measuring method according to claim 1 or 2, characterized in that, starting from the zero position with opposite amplitude values (41 A, 41 B) when the amplitude is zero, the current direction is changed.

4. Measuring method according to one of claims 1 to 3, characterized in that the transmitting coils (11, 12) are arranged at an angle to the receiving coil.

5. Measuring method according to one of the preceding claims, characterized in that the transmitting coils (11, 12) are arranged orthogonal to each other.

6. Measuring method according to one of the preceding claims, characterized in that for the three-dimensional position determination, a further transmitting coil is provided, the main axis intersects with the main axes of the at least two transmitting coils.

7. Measuring method according to claim 6, characterized in that the main axes span a Cartesian coordinate system.

8. Measuring method according to one of the preceding claims, characterized in that in a rectilinear relative movement of the components (B1, B2) to each other an angle determination is carried out, from which the position change is determined.

9. Measuring device for inductive angle and / or position determination of at least two components (B1, B2) to one another, wherein the one component (B1) at least two angularly arranged mutually, as a result of a current magnetic field forming transmitting coils (11, 12) are assigned and wherein the other component (B2) at least one receiving coil (13) is associated, in the current induced by the transmitting coils (11, 12) induces a current with

- At least one clock control (14) for alternately clocked operation of the at least two transmitting coils (11, 12),

Means (D) for assigning the amplitude values (41A, 41B) of the electrical signals (41) to the transmitting coils (11, 12),

- at least one comparator (16) for comparing the associated amplitude values (41 A, 41 B) of the electrical signal (41) to produce a comparison value (70) at the output (16c) of the comparator (16) for controlling the amplitude values of the in the transmitting coils (11, 12) flowing current by means of at least one regulator (17, 18), so that the transmission coils associated amplitude values (41 A, 41 B) of the electrical signal (41) at the inputs (16a, 16b) of the comparison (16) be the same size, characterized by a microprocessor (80) for detecting the ratio of the transmitting coils (11, 12) supplied currents to each other as a measure of the angular and / or position determination of the components (B1, B2) to each other.

10. Measuring device according to claim 9, characterized in that the controllers (17,18) are control stages with phase reversal, wherein the control values are represented by the currents on the lines (74,75), and a phase reversal occurs when at least one of the currents which are supplied to the at least two transmitting coils to the control limits of the current drivers for the transmitting coils (11, 12), which is determined by a power of zero.

11. Measuring device according to claim 9 or 10, characterized in that the transmitting coils (11, 12) are arranged at an angle to the receiving coil (13) and / or orthogonal to each other.

12. Measuring device according to one of claims 9 to 11, characterized in that the transmitting coils (11, 12) are arranged orthogonal to each other.

13. Measuring device according to one of claims 9 to 12, characterized in that for the three-dimensional position determination, a further transmitting coil is provided, whose main axis intersects with the main axes of the at least two transmitting coils.

14. Measuring device according to claim 13, characterized in that the main axes span a Cartesian coordinate system.