CN204085440U - The capacitive displacement precision measurement apparatus of double frequency excitation - Google Patents
The capacitive displacement precision measurement apparatus of double frequency excitation Download PDFInfo
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- CN204085440U CN204085440U CN201420587419.7U CN201420587419U CN204085440U CN 204085440 U CN204085440 U CN 204085440U CN 201420587419 U CN201420587419 U CN 201420587419U CN 204085440 U CN204085440 U CN 204085440U
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Abstract
The utility model discloses a kind of capacitive displacement precision measurement apparatus of double frequency excitation, tell double frequency excitation capacitive displacement precision measurement apparatus comprise emitting electrode insulated substrate 1 and receiving electrode insulated substrate 9.Low frequency 6, high frequency 5 sinusoidal voltage source superposition coupling 4 is adopted to encourage insulated substrate 1 emitting electrode 8, pass through capacitance coupling effect, pole span gap 20 change is converted to double frequency amplitude-modulated signal by receiving electrode 19, and obtains two-way displacive modulation voltage signal by high impedance buffering decoupling circuit 12, bandpass filtering amplifying circuit 13, precise rectification circuit 14.By judge two-way displacive modulation voltage signal magnitude relativeness can the displacement of accurate Calculation receiving electrode relative transmission electrode, movement velocity and direction.This capacitive displacement precision measurement process does not rely on the instantaneous amplitude of receiving electrode single channel output signal; Device scheme is flexible, and measuring accuracy is high, and sensing elements installation accuracy requires low, is easy to apply in low cost autonation device.
Description
Technical field
The utility model relates to a kind of electric approach checkout equipment, specifically a kind of capacitive displacement precision measurement apparatus of double frequency excitation.
Background technology
Along with the fast development of modern industry and science and technology, accurate and ultra precise measurement is more and more extensive in the application in the fields such as precision machinery technology, microelectric technique, Ultraprecision Machining.The precision measurement of displacement is one of topmost research direction in dimensional measurement, raising along with machining precision impels the innovation of more high-precision measuring technique and method, the surveying instrument of the method such as favourable grating, magnetic grid, laser in practical application, greatly enrich the means measured, also promote the future development that displacement measuring technology is measured toward high precision, wide range, multi-dimensional displacement simultaneously.Apply more accurate displacement measuring technique means and mainly contain in current industry and life: differential transformer displace￣ ment transducer, two-frequency laser interferometer, laser displacement sensor, grating scale, microscope measuring technology and capacitive displacement transducer etc.
Current accurate displacement fields of measurement, capacitive displacement transducer changes the capacity effect displacement transducer causing electrostatic capacitance amount to change especially by polar plate spacing, because having, structure is simple, dynamic response good, cost is low, good stability, measuring accuracy are high, can realize the features such as non-contact measurement and be widely used in every field.Because the electrostatic capacitance value between capacitive transducer two-plate is less, along with improving constantly of exciting signal frequency, coupled signal is not only decayed and seriously, is easily disturbed, and the linearity of front-end circuit is difficult to ensure.When adopting low-frequency excitation, although drive signal strength is comparatively large, to dynamic displacement, particularly the response speed of vibration signal is difficult to meet the demands; Adopt constant current driven mode, dynamic respond speed and precision can be improved, but containing larger direct current biasing in output signal; Adopt bipolar electrode model can reduce signal to be biased and drift, improve signal to noise ratio (S/N ratio), but testing circuit interference free performance is poor; Though adopt high-frequency drive mode can improve the sensitivity of effectively output signal, range of displacement measurement is limited.Above-mentioned factor makes current capacitive displacement precision measurement apparatus equip in the generality production that total amount is huge and apply limited in various daily device.
Summary of the invention
The utility model, for the deficiencies in the prior art, provides that a kind of scheme is flexible, measuring accuracy is high, and antijamming capability is strong, applies easy double frequency excitation capacitive displacement precision measurement apparatus.
The technical solution of the utility model is as follows:
A capacitive displacement precision measurement apparatus for double frequency excitation, is characterized in that: prepare emitting electrode in an insulated substrate bottom surface, and emitting electrode is a circular electrode, and electrode centers is connected with main line to front by a via hole, another insulated substrate prepares receiving electrode, simultaneously in order to reduce interference and marginal effect of electric field to the impact of measurement result, receiving electrode is closely surrounded by an equipotential ring structure, keeps electric insulation between the two, the overall dimensions of receiving electrode and equal potential belt and emitting electrode consistent size, screen layer is prepared, whole electrodes of screen layer complete covering lower surface on another surface of insulated substrate emitting electrode and receiving electrode, when carrying out accurate displacement measurement, emitting electrode insulated substrate is arranged on fixed reference, receiving electrode insulated substrate is arranged on mobile object, keep receiving electrode insulated substrate parallel with emitting electrode insulated substrate, emitting electrode aligns with receiving electrode center, a clearance is had between emitting electrode and receiving electrode, with the high frequency that amplitude is equal, stimulated emission electrode after low frequency two kinds of sinusoidal voltage source mixing superpositions, receiving electrode center is connected to voltage signal testing circuit by the main line that via hole is drawn, the displacement of the relative fixed reference of object being measured is drawn by DSP computational analysis receiving electrode two-way output displacement modulated voltage signal, dynamic response and detection resolution.
Emitting electrode of the present utility model accesses two amplitudes consistent high frequency, low-frequency sinusoidal AC voltages source superposed signal; Receiving electrode is just to time vertically mobile above emitting electrode, high frequency, the low-frequency sinusoidal AC voltages signal of receiving electrode coupling, its amplitude changes with the distance change moved up and down, and by corresponding C/V change-over circuit, can obtain the corresponding relation of distance and voltage.
The utility model shares an electrode emission signal by after high-frequency excitation signal, low-frequency excitation Signal averaging, by receiving electrode end decoupling circuit by signals revivification is and the high frequency of original signal same frequency, low frequency filtered signal.The different direct current signal of two-way can be obtained by subsequent amplification circuitry, precise rectification circuit.High frequency pumping mode can embody advantage in response speed; Lower frequency pumping system performance in displacement resolution, measurement range, the linearity, the index such as anti-interference is more excellent.
Receiving electrode size design of the present utility model is moderate, ensure that the intensity of output signal; Be clearance between emitting electrode and receiving electrode, displacement measurement process is noncontact working method, and mechanical friction and loss do not occur measuring process.
When the receiving electrode that between reception insulated substrate of the present utility model and transmitting insulated substrate, size of gaps, change in dielectric constant cause and emitting electrode coupling capacitance change, the high frequency that receiving electrode exports, the amplitude of low-frequency voltage signal synchronously change, by judge two groups of voltage signal magnitude relativeness can the displacement of accurate Calculation receiving electrode relative transmission electrode, movement velocity and direction of motion.
Displacement measurement process of the present utility model does not rely on the instantaneous amplitude of receiving electrode single channel output signal; The utility model scheme is flexible, and measuring accuracy is high, and sensing elements installation accuracy requires low, is easy to apply in low cost autonation device.
Accompanying drawing explanation
Fig. 1 is the utility model schematic diagram.
Fig. 2 is upper surface 1 schematic diagram of emitting electrode insulated substrate.
Fig. 3 is lower surface 7 schematic diagram of emitting electrode insulated substrate.
Fig. 4 is upper surface 9 schematic diagram of receiving electrode insulated substrate.
Fig. 5 is lower surface 17 schematic diagram of receiving electrode insulated substrate.
Embodiment
As shown in Figure 1, the capacitive displacement precision measurement method of double frequency excitation, is characterized in that:
A, prepare annular emission electrode 8 at the lower surface 7 of emitting electrode insulated substrate, the radius of annular emission electrode 8 is moderate, to ensure the intensity outputed signal; The circle centre position of annular emission electrode 8 has the via hole 2 of a minor diameter, electrically conducting (as shown in Figure 3) between via hole 2 and emitting electrode 8;
B, the upper surface 1 of emitting electrode insulated substrate prepare high frequency sinusoidal alternating voltage source circuit 5, low-frequency sinusoidal AC voltages source circuit 6 and superposition coupled circuit 4, high frequency sinusoidal alternating voltage source circuit 5 and low-frequency sinusoidal AC voltages source circuit 6 are connected with superposition coupled circuit 4 respectively, and superposition coupled circuit 4 is connected (as shown in Figure 2) with via hole 2 by main line 3;
C, prepare circular reception electrode 19 and an equal potential belt 18 at the lower surface 17 of receiving electrode insulated substrate, receiving electrode 19 closely surrounds by equal potential belt 18, electric insulation is kept between equal potential belt 18 and receiving electrode 19, equal potential belt 18 and the concyclic heart of receiving electrode 19, the overall dimensions of equal potential belt 18 and receiving electrode 19 and emitting electrode 8 consistent size, the circle centre position of circular reception electrode 19 has the via hole 10 of a minor diameter, electrically conducting (as shown in Figure 5) between via hole 10 and receiving electrode 19;
D, prepare HF voltage testing circuit 15, low-frequency voltage testing circuit 16, rectification circuit 14, amplifying circuit 13 and decoupling circuit 12 at the upper surface 9 of receiving electrode insulated substrate, via hole 10 is connected to decoupling circuit 12 by main line 11, decoupling circuit 12 is connected with amplifying circuit 13, amplifying circuit 13 is connected with rectification circuit 14, and rectification circuit 14 is connected respectively on HF voltage testing circuit 15 and low-frequency voltage testing circuit 16 (as shown in Figure 4);
E, be arranged on a steel pedestal by emitting electrode insulated substrate 1 by a manual adjustments precision displacement table, receiving electrode insulated substrate 9 is fixed on the Z axis platform of displacement platform by alloy L-type fixture.In test process, first the X-axis of adjusted position moving stage and Y-axis make emitting electrode 8 and receiving electrode 19 keep center to align, and the Z axis of displacement platform is used for producing adjustable air gap 20, i.e. significance bit shifting signal (as shown in Figure 1);
F, the receiving electrode 19 that between reception insulated substrate 9 and transmitting insulated substrate 1, size of gaps, change in dielectric constant cause change (as shown in Figure 1) with emitting electrode 8 coupling capacitance;
Mixed frequency signal decoupling zero first by forming buffering decoupling circuit 12 by the RLC series resonance filtering circuit of high input impedance amplifier and two groups of high frequencies, low frequency, thus is obtained two-way high frequency, low frequency amplitude-modulated signal by the coupled signal of the utility model receiving electrode 19.The amplitude-modulated signal that RLC wave filter exports is by obtaining final two-way displacive modulation voltage signal (as shown in Figure 4,5) after amplifying circuit 13 and precise rectification circuit 14;
The utility model adopts the high frequency amplifier chip drives emitting electrode 8 for capacitive load, and high frequency sinusoidal alternating voltage source circuit 5 and low-frequency sinusoidal AC voltages source circuit 6 have employed active crystal oscillator multivibrator and RLC series resonance bandpass filter produces sinusoidal signal (as shown in Figure 1, 2);
The utility model reference bit shifting signal is based on high accuracy number pulse length meter, reference bit shifting signal and receiving electrode insulated substrate 9 export two-way displacive modulation voltage signal and carry out synchronized sampling and data analysis respectively by enhancing quadrature coding pulse (eQEP) module of dsp chip and high-precision analog digital conversion chip (A/D), obtain the real time value relation (as shown in Figure 1) of double frequency displacive modulation voltage signal and polar plate spacing 20;
The utility model according to the real time value relation of the double frequency displacive modulation voltage signal obtained and polar plate spacing 20, can the displacement of accurate Calculation receiving electrode relative transmission electrode, movement velocity and direction of motion (as shown in Figure 1);
The high input impedance amplifier model that the utility model adopts is THS4631, and the high frequency amplifier chip model of employing is THS4041 (Texas instruments);
The high accuracy number pulse length meter (Magnescale DK812VR Japan) that the utility model adopts, its range is 12mm, resolution 0.1 μm, and full scale measuring accuracy is 1 μm, and maximum displacement response speed is 42m/min;
The dsp chip that the utility model adopts is TMS320F28335, and the high-precision analog digital conversion chip (A/D) of employing is AD7606;
Insulated substrate of the present utility model adopts printed circuit board (PCB) (Printed Circuit Board-PCB) technique to make.PCB technology has that structure is simple, cost is low, the cycle that designs and produces is short, lightweight and is easy to the advantage such as fixing.
Claims (7)
1. a capacitive displacement precision measurement apparatus for double frequency excitation, is characterized in that: prepare emitting electrode in an insulated substrate bottom surface, and emitting electrode is a circular electrode, and electrode centers is connected with main line to front by a via hole, another insulated substrate prepares receiving electrode, simultaneously in order to reduce interference and marginal effect of electric field to the impact of measurement result, receiving electrode is closely surrounded by an equipotential ring structure, keeps electric insulation between the two, the overall dimensions of receiving electrode and equal potential belt and emitting electrode consistent size, screen layer is prepared, whole electrodes of screen layer complete covering lower surface on another surface of insulated substrate emitting electrode and receiving electrode, when carrying out accurate displacement measurement, emitting electrode insulated substrate is arranged on fixed reference, receiving electrode insulated substrate is arranged on mobile object, keep receiving electrode insulated substrate parallel with emitting electrode insulated substrate, emitting electrode aligns with receiving electrode center, a clearance is had between emitting electrode and receiving electrode, with the high frequency that amplitude is equal, stimulated emission electrode after low frequency two kinds of sinusoidal voltage source mixing superpositions, receiving electrode center is connected to voltage signal testing circuit by the main line that via hole is drawn, the displacement of the relative fixed reference of object being measured is drawn by DSP computational analysis receiving electrode two-way output displacement modulated voltage signal, dynamic response and detection resolution.
2. the capacitive displacement precision measurement apparatus of double frequency excitation according to claim 1, is characterized in that: emitting electrode accesses two amplitudes consistent high frequency, low-frequency sinusoidal AC voltages source superposed signal simultaneously.
3. the capacitive displacement precision measurement apparatus of double frequency excitation according to claim 1 and 2, it is characterized in that: share an electrode emission signal after high-frequency excitation signal, low-frequency excitation Signal averaging, by receiving electrode end decoupling circuit by signals revivification be and the high frequency of original signal same frequency, low frequency filtered signal.The different direct current signal of two-way can be obtained by subsequent amplification circuitry, precise rectification circuit.
4. the capacitive displacement precision measurement apparatus of double frequency excitation according to claim 1, is characterized in that: be clearance between emitting electrode and receiving electrode, displacement measurement process is noncontact working method, and mechanical friction and loss do not occur measuring process.
5. the capacitive displacement precision measurement apparatus of double frequency excitation according to claim 1, is characterized in that: prepare screen layer on another surface of insulated substrate emitting electrode and receiving electrode, whole electrodes of screen layer complete covering lower surface.
6. the capacitive displacement precision measurement apparatus of double frequency excitation according to claim 1, it is characterized in that: emitting electrode and receiving electrode keep center alignment, when receiving electrode upper and lower vertically moves, the high frequency that receiving electrode decoupling zero is amplified, the amplitude of low-frequency voltage signal synchronously change.
7. the capacitive displacement precision measurement apparatus of double frequency excitation according to claim 1, is characterized in that: effective range of the present utility model is 0-1.5mm.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104697424A (en) * | 2015-03-04 | 2015-06-10 | 浙江师范大学 | Double-frequency four-quadrant plane coordinate position detection method |
| CN105890552A (en) * | 2016-04-06 | 2016-08-24 | 浙江师范大学 | Three-degree of freedom linear displacement detection method |
| CN106289043A (en) * | 2016-08-10 | 2017-01-04 | 成都芯通科技股份有限公司 | A kind of capacitive distance measuring method, device and calibrating method thereof |
| CN107102782A (en) * | 2016-02-22 | 2017-08-29 | 台湾艾华电子工业股份有限公司 | Position sensor and its type variable capacitance component |
| CN108761710A (en) * | 2017-04-03 | 2018-11-06 | 三星电机株式会社 | The actuator and camera model of camera model |
| CN115824026A (en) * | 2023-02-14 | 2023-03-21 | 南方科技大学 | Differential resonant cavity displacement sensing system |
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2014
- 2014-09-29 CN CN201420587419.7U patent/CN204085440U/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104697424A (en) * | 2015-03-04 | 2015-06-10 | 浙江师范大学 | Double-frequency four-quadrant plane coordinate position detection method |
| CN107102782A (en) * | 2016-02-22 | 2017-08-29 | 台湾艾华电子工业股份有限公司 | Position sensor and its type variable capacitance component |
| CN107102782B (en) * | 2016-02-22 | 2023-03-14 | 台湾艾华电子工业股份有限公司 | Position sensor and variable capacitance component thereof |
| CN105890552A (en) * | 2016-04-06 | 2016-08-24 | 浙江师范大学 | Three-degree of freedom linear displacement detection method |
| CN105890552B (en) * | 2016-04-06 | 2018-11-20 | 浙江师范大学 | A kind of Three Degree Of Freedom linear displacement detecting method |
| CN106289043A (en) * | 2016-08-10 | 2017-01-04 | 成都芯通科技股份有限公司 | A kind of capacitive distance measuring method, device and calibrating method thereof |
| CN106289043B (en) * | 2016-08-10 | 2019-04-12 | 成都芯通软件有限公司 | A kind of capacitive distance measurement method, device and its calibrating method |
| CN108761710A (en) * | 2017-04-03 | 2018-11-06 | 三星电机株式会社 | The actuator and camera model of camera model |
| CN115824026A (en) * | 2023-02-14 | 2023-03-21 | 南方科技大学 | Differential resonant cavity displacement sensing system |
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