CN106225657B - displacement sensor - Google Patents
displacement sensor Download PDFInfo
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- CN106225657B CN106225657B CN201610662236.0A CN201610662236A CN106225657B CN 106225657 B CN106225657 B CN 106225657B CN 201610662236 A CN201610662236 A CN 201610662236A CN 106225657 B CN106225657 B CN 106225657B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness
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- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
The invention discloses a displacement sensor which comprises a voltage-stabilized power supply, an oscillator and a detection circuit. An oscillator, the power supply input end of which is coupled with the output end of the stabilized voltage power supply, is provided with a coil which is arranged opposite to the metal conductor. The oscillator gradually decreases the oscillation amplitude as the metal conductor gradually approaches the coil so that the regulated power supply gradually decreases the current at its output. The detection circuit is adapted to detect an electrical signal corresponding to a current value at the output of the regulated power supply. The control unit is coupled with the detection circuit and is suitable for calculating the distance between the metal conductor and the coil according to the electric signal.
Description
Technical Field
The invention relates to the technical field of equipment monitoring, in particular to a displacement sensor.
Background
The displacement sensor is also called a linear sensor, and belongs to a metal induction linear device. Common displacement sensors are for example hall or eddy current type, etc. Fig. 1 shows the operating principle of an eddy current sensor. The working mechanism of the eddy current displacement sensor system is that an LC oscillator is formed by a probe (namely a wound coil, equivalent to an inductor) and an internal circuit. An alternating magnetic field H1 is generated around the probe head. If no metallic conductor material is in proximity within the range of the magnetic field H1, all of the energy emitted into this range is released. Conversely, if there is metallic conductor material close to the probe head, the alternating magnetic field H1 will generate an electric eddy current field on the surface of the conductor, which will also generate an alternating magnetic field H2 in the opposite direction to H1. Due to the reaction of H2, the amplitude and phase of the probe head coil high frequency current are changed.
Fig. 2 shows a block diagram of a conventional eddy current displacement sensor. The oscillator in the sensor generates a high-frequency current signal by a fixed capacitance and inductance (C1, C2 and Lx in the figure) parallel resonance method. An alternating magnetic field H1 is generated around the probe head. When the metallic conductor material approaches the probe head, the alternating magnetic field H1 generates an eddy current field at the surface of the conductor. The eddy current field generates an alternating magnetic field H2 in a direction opposite to H1. Due to the reaction of H2, the amplitude and phase of the probe head coil high frequency current are changed. Thus, the oscillation amplitude Ux of the oscillator changes as the probe-to-measured distance δ changes. The existing technical scheme is to perform a series of processing such as detection filtering, amplification and linear correction on Ux, so as to determine the value of the distance delta between the probe and the measured object through the value of the output voltage Uo.
However, in a high-precision application scenario, the oscillator of the conventional displacement sensor has a problem of drift and the like when influenced by an environment such as temperature. Accordingly, the measurement values of the displacement sensors may deviate due to the influence of environmental conditions.
Therefore, the invention provides a novel displacement sensor technical scheme.
Disclosure of Invention
Therefore, the invention provides a new displacement sensor technical scheme, and at least one of the problems is effectively solved.
According to one aspect of the present invention, a displacement sensor is provided that includes a regulated power supply, an oscillator, and a detection circuit. An oscillator, the power supply input end of which is coupled with the output end of the stabilized voltage power supply, is provided with a coil which is arranged opposite to the metal conductor. The oscillator gradually decreases the oscillation amplitude as the metal conductor gradually approaches the coil so that the regulated power supply gradually decreases the current at its output. The detection circuit is adapted to detect an electrical signal corresponding to a current value at the output of the regulated power supply. The control unit is coupled with the detection circuit and is suitable for calculating the distance between the metal conductor and the coil according to the electric signal.
optionally, in the displacement sensor according to the present invention, the output terminal of the regulated power supply is provided with a current detection resistor. The detection circuit is adapted to detect a voltage value across the current detection resistor as an electrical signal.
optionally, in the displacement sensor according to the present invention, the regulated power supply includes an amplifier U1. The non-inverting input end of the amplifier is connected with a direct current power supply, and the inverting input end of the amplifier is provided with a first pull-down resistor R1. And a second resistor R2 is connected between the output end and the inverting input end of the stabilized voltage power supply. The current detection resistor R3 is connected between the output end of the voltage-stabilized power supply and the output end of the amplifier U1.
Alternatively, in the displacement sensor according to the present invention, the oscillator includes a transistor Q1. An emitter of the transistor Q1 is connected with a pull-down fourth resistor R4, and a fifth resistor R5 is connected between a base and the power supply input end VCC. A coil L and a first capacitor C1 are connected in parallel between the collector of the transistor Q1 and the power supply input terminal VCC. A second capacitor C2 is connected between the emitter and the collector. A third capacitor C3 is connected between the emitter and the supply input. The power supply input VCC of the oscillator is connected to a bypass capacitor C4. As the metal conductor gradually approaches the coil L, the current value gradually decreases.
Alternatively, in the displacement sensor according to the invention the control unit is adapted to determine a current value from the electrical signal and to calculate the distance of the metal conductor from the coil from the current value. The sensor may further comprise a wireless communication unit to which the control unit is coupled. The control unit is adapted to transmit the calculated distance to the outside through the wireless communication unit. The control unit is for example a Microprocessor (MCU). The wireless communication unit is, for example, ZigBee.
In summary, the displacement sensor of the present invention measures the distance between the oscillator coil and the metal conductor from the angle of energy change. When the metal conductor is gradually close to the coil of the oscillator, the current output to the oscillator by the voltage-stabilized power supply is gradually reduced. Therefore, the technical scheme of the invention can determine the distance between the metal conductor and the coil by detecting the change of the current at the output end of the stabilized voltage supply. However, the oscillation amplitude of the oscillator is susceptible to environmental influences that cause shifts (e.g., temperature drift, etc.). However, the output current of the regulated power supply is much less affected by the environment than the oscillation amplitude. Therefore, compared with the traditional mode of measuring the oscillation amplitude change, the displacement sensor has better accuracy and anti-interference capability.
Drawings
to the accomplishment of the foregoing and related ends, certain illustrative aspects are described herein in connection with the following description and the annexed drawings, which are indicative of various ways in which the principles disclosed herein may be practiced, and all aspects and equivalents thereof are intended to be within the scope of the claimed subject matter. The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description read in conjunction with the accompanying drawings. Throughout this disclosure, like reference numerals generally refer to like parts or elements.
FIG. 1 shows a working principle diagram of an eddy current sensor;
Fig. 2 shows a block diagram of a typical eddy current type displacement sensor;
FIG. 3 illustrates a schematic diagram of a displacement sensor 300 according to some embodiments of the invention;
FIG. 4 shows a schematic diagram of regulated power supply 400 according to one embodiment of the invention; and
fig. 5 shows a schematic diagram of an oscillator 500 according to an embodiment.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
FIG. 3 illustrates a schematic diagram of a displacement sensor 300 according to some embodiments of the invention. As shown in fig. 3, the displacement sensor 300 includes a regulated power supply 310, an oscillator 320, a detection circuit 330, and a control unit 340. The oscillator 320 has a coil disposed opposite a metal conductor. Here, the regulated power supply 310 is a dc regulated power supply and can output a stable voltage to the oscillator 320. Here, the regulated power supply 310 may be any of various known regulated dc power supplies, or may be a regulated power supply as shown in fig. 4. Oscillator 320 may be any of a variety of known LC oscillator circuits, and may also be the oscillator shown in fig. 5, which is not intended to be limiting. Unlike conventional eddy current sensors (which sense the amplitude of oscillation of the oscillator), the sensing circuit 330 of the present invention is adapted to sense an electrical signal at the output of regulated power supply 310 (coupled to the supply input of oscillator 320) corresponding to a current value. Here, the electric signal is, for example, a voltage value across the current detection resistor. However, the present invention is not limited thereto, and various known methods for detecting the magnitude of the current may be applied to the present invention. The control unit 340 is, for example, a Microprocessor (MCU), but is not limited thereto.
It should be noted that the displacement sensor 300 of the present invention considers the distance between the coil of the oscillator 320 and the metal conductor (not shown) from the viewpoint of the change in energy. Specifically, when the metal conductor is away from the coil of the oscillator 320, the energy in the coil is released directly. When the metal conductor is close to the coil of the oscillator 320, the eddy current field energy in the metal conductor may be fed back to the coil due to the eddy current effect. Here, the closer the metal conductor is to the coil, the more energy is fed back to the coil. Accordingly, oscillator 320 gradually decreases the oscillation amplitude as the metal conductor gradually approaches the coil of oscillator 320, and causes regulated power supply 310 to gradually decrease the current at the output.
in summary, as the metal conductor gets closer to the coil of oscillator 320, the current output from regulated power supply 310 to oscillator 320 gradually decreases. Thus, the control unit 340 can determine the distance between the metal conductor and the coil according to the current change at the output end of the regulated power supply 310 obtained from the detection circuit 330. In particular, control unit 340 is adapted to determine the current value at the output of regulated power supply 310 based on the electrical signal provided by detection circuit 330. Further, the control unit 340 may calculate the distance of the metal conductor from the coil according to the current value. In addition, when the electrical signal is a voltage signal corresponding to a current value, the control unit 340 may calculate the distance between the metal conductor and the coil directly from the voltage signal. The control unit 640 may also choose to store the calculated distance.
Optionally, the displacement sensor 300 of the present invention may further include a wireless communication unit (not shown). The wireless communication unit is, for example, ZigBee, or other communication units such as WiFi or 4G. The control unit 640 may select the calculated distance to be transmitted to the outside through the wireless communication unit.
In particular, when the distance between the metal conductor and the coil is not changed, the oscillation amplitude of the oscillator 320 is likely to be shifted (for example, temperature drift) by the environmental influence. However, the output current of regulated power supply 310 is much less environmentally affected than the oscillation amplitude. Therefore, the displacement sensor 300 of the present invention has better accuracy and interference rejection than the conventional way of measuring the oscillation amplitude variation.
FIG. 4 shows a schematic diagram of regulated power supply 400 according to one embodiment of the invention. As shown in FIG. 4, regulated power supply 400 includes amplifier U1. The non-inverting input terminal of the amplifier U1 is connected to a dc power supply. The inverting input of amplifier U1 is provided with a pull-down resistor R1. A second resistor R2 is connected between the output terminal and the inverting input terminal of the regulated power supply 400, and a current detection resistor R3 is connected between the output terminal of the regulated power supply and the output terminal of the amplifier U1. Here, the current detection resistor R3 is a very small resistor. The detection circuit (330) can measure the voltage of R3 and use the voltage as an electric signal corresponding to the output current of the regulated power supply.
Fig. 5 shows a schematic diagram of an oscillator 500 according to an embodiment. As shown in fig. 5, the oscillator 500 includes a transistor Q1. The emitter of the transistor Q1 is connected with a fourth pull-down resistor R4, and a fifth resistor R5 is connected between the base and the power supply input terminal VCC. A coil L and a first capacitor C1 are connected in parallel between the collector of the transistor Q1 and the power supply input terminal VCC. A second capacitor C2 is connected between the emitter and the collector of the transistor Q1, and a third capacitor C3 is connected between the emitter and the power supply input terminal. Optionally, a bypass capacitor C4 is connected to the supply input VCC of the oscillator 500.
In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be interpreted as reflecting an intention that: that the invention as claimed requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.
those skilled in the art will appreciate that the modules or units or components of the devices in the examples disclosed herein may be arranged in a device as described in this embodiment or alternatively may be located in one or more devices different from the devices in this example. The modules in the foregoing examples may be combined into one module or may be further divided into multiple sub-modules.
those skilled in the art will appreciate that the modules in the device in an embodiment may be adaptively changed and disposed in one or more devices different from the embodiment. The modules or units or components of the embodiments may be combined into one module or unit or component, and furthermore they may be divided into a plurality of sub-modules or sub-units or sub-components. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where at least some of such features and/or processes or elements are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.
Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.
Furthermore, some of the described embodiments are described herein as a method or combination of method elements that can be performed by a processor of a computer system or by other means of performing the described functions. A processor having the necessary instructions for carrying out the method or method elements thus forms a means for carrying out the method or method elements. Further, the elements of the apparatus embodiments described herein are examples of the following apparatus: the apparatus is used to implement the functions performed by the elements for the purpose of carrying out the invention.
as used herein, unless otherwise specified the use of the ordinal adjectives "first", "second", "third", etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this description, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as described herein. Furthermore, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter. Accordingly, many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the appended claims. The present invention has been disclosed in an illustrative rather than a restrictive sense, and the scope of the present invention is defined by the appended claims.
Claims (8)
1. A displacement sensor, comprising:
A regulated power supply;
The oscillator is provided with a coil arranged opposite to the metal conductor, and the oscillation amplitude is gradually reduced when the metal conductor is gradually close to the coil, so that the current of the output end is gradually reduced by the stabilized voltage supply; and
The detection circuit is suitable for detecting an electric signal corresponding to the current value of the output end of the stabilized voltage power supply; and
And the control unit is coupled with the detection circuit and is suitable for determining the current value according to the electric signal so as to calculate the distance between the metal conductor and the coil.
2. The sensor of claim 1, wherein the output of the regulated power supply is provided with a current sensing resistor;
The detection circuit is suitable for detecting the voltage values at two ends of the current detection resistor as the electric signals.
3. The sensor of claim 2, wherein the regulated power supply comprises an amplifier (U1), a dc power supply is connected to a non-inverting input of the amplifier (U1), a first resistor (R1) is provided to a pull-down inverting input, a second resistor (R2) is connected between the output of the regulated power supply and the inverting input, and the current sense resistor (R3) is connected between the output of the regulated power supply and the output of the amplifier (U1).
4. The sensor of claim 1, wherein the oscillator comprises a transistor (Q1),
The emitter of the resistor is connected with a fourth resistor (R4) which is pulled down, a fifth resistor (R5) is connected between the base of the resistor and the power supply input end (VCC),
a coil (L) and a first capacitor (C1) which are connected in parallel are connected between the collector of the transformer and a power supply input end (VCC),
A second capacitor (C2) is connected between the emitter and the collector,
A third capacitor (C3) is connected between the emitter and the supply input.
5. the sensor according to claim 4, wherein a bypass capacitance (C4) is connected to the supply input (VCC) of the oscillator.
6. The sensor of claim 5, further comprising a wireless communication unit coupled to the control unit;
The control unit is adapted to transmit the calculated distance to the outside through the wireless communication unit.
7. The sensor of claim 6, wherein the control unit comprises a Microprocessor (MCU).
8. The sensor of claim 6, wherein the wireless communication unit is ZigBee.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201610662236.0A CN106225657B (en) | 2016-08-12 | 2016-08-12 | displacement sensor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610662236.0A CN106225657B (en) | 2016-08-12 | 2016-08-12 | displacement sensor |
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| CN106225657A CN106225657A (en) | 2016-12-14 |
| CN106225657B true CN106225657B (en) | 2019-12-06 |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112513580A (en) * | 2019-08-02 | 2021-03-16 | 深圳市越疆科技有限公司 | Mechanical equipment shell and robot |
| CN114018144A (en) * | 2021-10-28 | 2022-02-08 | 上海隐冠半导体技术有限公司 | Sensor detection circuit and sensor detection method |
| CN116772702A (en) * | 2023-08-24 | 2023-09-19 | 河南卫华重型机械股份有限公司 | Eddy current distance acquisition circuit |
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| JPS6114501A (en) * | 1984-06-30 | 1986-01-22 | Nippon Kokan Kk <Nkk> | Eddy current type range finder |
| JPS6182117A (en) * | 1984-09-29 | 1986-04-25 | Nippon Kokan Kk <Nkk> | Direct current feedback type eddy current range finder |
| CN2283829Y (en) * | 1996-12-10 | 1998-06-10 | 姚广仁 | Intelligence magnetic means coating thickness measuring instrument |
| CN201247043Y (en) * | 2008-08-19 | 2009-05-27 | 江祥红 | Linear corrective circuit for electric vortex flow sensor |
| CN102072694A (en) * | 2010-12-15 | 2011-05-25 | 北京经纬恒润科技有限公司 | Eddy current distance sensor |
| CN105333808A (en) * | 2015-11-25 | 2016-02-17 | 珠海格力节能环保制冷技术研究中心有限公司 | Displacement detection circuit, eddy current displacement sensor as well as correcting circuit and method thereof |
-
2016
- 2016-08-12 CN CN201610662236.0A patent/CN106225657B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6114501A (en) * | 1984-06-30 | 1986-01-22 | Nippon Kokan Kk <Nkk> | Eddy current type range finder |
| JPS6182117A (en) * | 1984-09-29 | 1986-04-25 | Nippon Kokan Kk <Nkk> | Direct current feedback type eddy current range finder |
| CN2283829Y (en) * | 1996-12-10 | 1998-06-10 | 姚广仁 | Intelligence magnetic means coating thickness measuring instrument |
| CN201247043Y (en) * | 2008-08-19 | 2009-05-27 | 江祥红 | Linear corrective circuit for electric vortex flow sensor |
| CN102072694A (en) * | 2010-12-15 | 2011-05-25 | 北京经纬恒润科技有限公司 | Eddy current distance sensor |
| CN105333808A (en) * | 2015-11-25 | 2016-02-17 | 珠海格力节能环保制冷技术研究中心有限公司 | Displacement detection circuit, eddy current displacement sensor as well as correcting circuit and method thereof |
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