Capacitive distance measurement method and device and calibration method thereof

A distance measurement and capacitive technology, which is applied in the field of capacitive distance measurement, can solve the problems that it is difficult to meet the measurement accuracy requirements of millimeter level, the ultrasonic distance measurement environment has a great influence, and the device is complicated and huge, so as to expand the dynamic range of measurement and increase the accuracy. Large measurement dynamic range, overcome the effect of mutual interference

Active Publication Date: 2017-01-04
成都芯通软件有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, some can achieve high measurement accuracy, but they cannot be applied to short-distance measurement due to the complexity of the device; The environment has a great impact, and it is difficult to meet the measurement accuracy requirements on the order of millimeters; some, such as capacitive sensor products, are basically aimed at switch application scenarios, and their measurement accuracy is very limited, so they cannot be used to accurately measure distances, and they support The number of probes is small, because the mutual interference between the probes is serious during the probe expansion, resulting in a serious drop in measurement accuracy, so it is impossible to expand the number of probes according to the demand

Method used

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  • Capacitive distance measurement method and device and calibration method thereof
  • Capacitive distance measurement method and device and calibration method thereof
  • Capacitive distance measurement method and device and calibration method thereof

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Experimental program
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Embodiment 1

[0049]A capacitive distance measuring device disclosed in an embodiment of the present invention includes: a probe, an excitation unit, a capacitive voltage conversion unit, a logarithmic amplification processing unit, a data acquisition conversion unit, and a control unit.

[0050] Such as figure 1 As shown, the capacitor Cs is formed between the probe and the tested part. When the relative distance between the tested part and the probe changes, the capacitance of the capacitor Cs changes accordingly. The larger the distance, the smaller the capacitance. By measuring the capacitance The relative distance between the DUT and the probe can be measured.

[0051] Wherein, the excitation unit is connected with the probe, and is used to apply the first excitation signal to the probe; specifically, the excitation unit may include a digital-to-analog converter (Digital-To-Analog Converter, DAC), which is used to generate such as a phase-shifted sine wave signal, Excitation signals s...

Embodiment 2

[0057] Such as figure 2 As shown, on the basis of the aforementioned device, the capacitive distance measuring device disclosed in a preferred embodiment of the present invention further includes a shielding layer arranged on the back of the probe, connected to the excitation unit, and the medium between the probe and the shielding layer can be an insulating isolation material or other filler material;

[0058] Correspondingly, the excitation unit is also used to apply a second excitation signal to the probe; wherein the amplitude and phase of the second excitation signal are the same as those of the first excitation signal. The control unit can also be used to determine the phase, amplitude, etc. of the first excitation signal applied by the excitation unit.

[0059] In a preferred embodiment, the above device may further include a display unit connected to the control unit for displaying the distance value, for example, an electronic display device such as a liquid crystal...

Embodiment 3

[0063] A capacitive distance measuring device disclosed in a preferred embodiment of the present invention, on the basis of the aforementioned device, further includes: image 3 The excitation sampling circuit shown. Among them, the excitation unit is connected to the probe (that is, the probe side of the capacitor Cs) through the sampling resistor Rs, and the excitation signal is applied to the probe; the capacitance-voltage conversion unit is connected to the instrumentation amplifier (Instrumentation Amplifier, INA) across the sampling resistor Rs, for example, A precision low-power instrumentation amplifier to acquire the first voltage signal.

[0064] Specifically, if the formula for calculating the capacitance of a plate capacitor is simplified, the relationship between the voltage and the distance can be approximated as V s =V 0 +k / D, where, Vs represents the voltage across the resistor Rs, V0 represents the relative voltage of the capacitor Cs, D represents the dista...

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Abstract

The present invention relates to a capacitive distance measurement method. The method comprises the steps of using a control unit to determine the time when an excitation unit applies a first excitation signal; using the excitation unit to apply the first excitation signal to a probe; using a capacitance-voltage conversion unit to obtain a first voltage signal corresponding to the capacitance formed between the probe and a measured member; using the control unit to determine the time when a logarithm amplification processing unit carries out the logarithm amplification processing; using the logarithm amplification processing unit to carry out the logarithm amplification processing on the first voltage signal to obtain a second voltage signal; using a data acquisition conversion unit to convert the second voltage signal into a third voltage signal; using the control unit to convert the third voltage signal into a distance value. The present invention also discloses a capacitive distance measurement device and a calibration method thereof.

Description

technical field [0001] The invention relates to the technical field of electronic distance measurement, in particular to a capacitive distance measurement method, device and calibration method thereof. Background technique [0002] In the prior art, there are many kinds of sensing devices for distance measurement, such as laser ranging, infrared ranging, radio ranging, ultrasonic ranging, image recognition ranging, and capacitive sensor ranging. Among them, some can achieve high measurement accuracy, but they cannot be applied to short-distance measurement due to the complexity of the device; The environment has a great impact, and it is difficult to meet the measurement accuracy requirements on the order of millimeters; some, such as capacitive sensor products, are basically aimed at switch application scenarios, and their measurement accuracy is very limited, so they cannot be used to accurately measure distances, and they support The number of probes is small, because th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01B7/14
CPCG01B7/14
Inventor 余飞王斌
Owner 成都芯通软件有限公司
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