CN110398196A - A kind of LVDT sensor signal processing method and system for accurate measurement - Google Patents
A kind of LVDT sensor signal processing method and system for accurate measurement Download PDFInfo
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- CN110398196A CN110398196A CN201910654419.1A CN201910654419A CN110398196A CN 110398196 A CN110398196 A CN 110398196A CN 201910654419 A CN201910654419 A CN 201910654419A CN 110398196 A CN110398196 A CN 110398196A
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- signal
- lvdt sensor
- accurate measurement
- pulse signal
- sampling
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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
-
- 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
- G01B7/12—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring diameters
-
- 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
- G01B7/12—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring diameters
- G01B7/13—Internal diameters
Abstract
The invention belongs to mechanical workpieces field of measuring technique, and in particular to a kind of LVDT sensor signal processing method and system for accurate measurement, method include the following steps: step 1: obtain the analog signal of LVDT sensor output as pumping signal；Step 2: frequency, pulsewidth and the delay of pulse signal are set according to pumping signal；Step 3: frequency, pulsewidth and the delay of the pulse signal obtained using step 2 are carried out reconnaissance to the pumping signal that step 1 obtains and sample to obtain multiple sampled points, and smothing filtering is then overlapped and carried out to the signal amplitude of all sampled points, obtains pseudo- direct current signal；Step 4: pseudo- direct current signal being compensated, smothing filtering, output digit signals are then passed through.The present invention settles tri- acquisition, conditioning, AD steps at one go, improves the response speed of system, the requirement suitable for accurate measurement.
Description
Technical field
The invention belongs to mechanical workpieces field of measuring technique, and in particular to a kind of LVDT sensor letter for accurate measurement
Number processing method and system.
Background technique
In recent years, measuring technique is widely used to Aeronautics and Astronautics, automobile, high-accuracy mechanical manufacture, novel electron, new
In the new-product development of the industries such as the energy, medical joint prosthesis and the quality control of production process.Sensor can be by small position
Shifting amount is converted to analog electric signal, if be AD converted to the analog signals, is converted to digital signal, so that it may obtain
Corresponding displacement, and ensure with this precision of required workpiece.
In traditional high precision measuring system, such as demodulation scheme shown in Fig. 2, to analog quantity electricity after completing demodulation
When signal is AD converted, often require to export digital quantity signal equipped with high-order A/D converter.Both occupied space in this way
Increase cost again so that high precision measuring instrument often tall and big heaviness, inconvenient for use, however and small and exquisite measuring instrument not
It is able to satisfy precision and requirement functionally.Also there is the insufficient defect of flexibility using hardware demodulation simultaneously, come relative to software
It says, hardware realization often faces more difficulties when changing parameter.Such as when we need to modify the frequency of driving signal,
Hardware generally requires replacement component, this is very inconvenient.
Summary of the invention
It is big for circuit volume present in existing signal processing scheme, many and diverse problem of signal processing, this hair
It is bright to provide a kind of LVDT sensor signal processing method and system based on fine measuring instrument, adopt the following technical scheme that reality
It is existing:
A kind of LVDT sensor signal processing method for accurate measurement, includes the following steps:
Step 1: obtaining the analog signal of LVDT sensor output as pumping signal；
Step 2: frequency, pulsewidth and the delay of pulse signal are set according to pumping signal；
Step 3: the pumping signal that frequency, pulsewidth and the delay of the pulse signal obtained using step 2 obtain step 1 into
Row reconnaissance samples to obtain multiple sampled points, and smothing filtering is then overlapped and carried out to the signal amplitude of all sampled points, is obtained
To pseudo- direct current signal；
Step 4: pseudo- direct current signal being compensated, smothing filtering, output digit signals are then passed through
Further, packet is overlapped to the sampling of pumping signal in step 2 and to the signal amplitude of all sampled points
Include following steps:
Step a: respectively choosing q point to all wave crests in the pumping signal in the continuous n period and trough and complete sampling,
Middle n, q are positive integer；
Step b: being overlapped the range value of all wave crest sampled points, and the range value of all trough sampled points takes absolute value
After be overlapped, the summation of value after being finally overlapped twice.
Further, the smothing filtering is the smoothing processing of 2n point.
Further, the pulse signal frequency f that single-chip microcontroller is arranged is twice of exciting signal frequency, and pulse signal is arranged
Pulsewidth P and delay Td make Td=T-P/2, T is the period of pulse signal and T=1/f, the pulse signal frequency f=
10KHz, the pulsewidth P=20 μ s, the delay Td90 μ s.
Further, pseudo- direct current signal is compensated including linear compensation and nonlinear compensation in step 3.
A kind of LVDT sensor signal processing system for accurate measurement, comprising: LVDT sensor unit, pulse signal
Parameter set unit, sampling and superpositing unit and compensating unit；
The LVDT sensor unit is for exporting analog signal and passing it to excitation of the single-chip microcontroller as single-chip microcontroller
Signal；The pulse signal parameter set unit is used to be arranged according to pumping signal frequency, the pulsewidth of the pulse signal of single-chip microcontroller
And delay；The sampling and superpositing unit are used to sample pumping signal using the frequency, pulsewidth and delay of pulse signal,
Then smothing filtering is overlapped and carried out to the signal amplitude of all sampled points, obtains pseudo- direct current signal；The compensating unit
For being compensated to the pseudo- direct current signal of sampling and superpositing unit output, then carries out smothing filtering and obtain digital signal.
Further, sampling and superpositing unit include sampling subelement and superposition subelement；
The sampling subelement is used to respectively choose all wave crests in the pumping signal in the continuous n period and trough q
Point, wherein n, q are positive integer；
The superposition subelement is used to that being overlapped the range value of all wave crest sampled points of subelement output will to be sampled,
The range value of all trough sampled points is overlapped after taking absolute value, the value summation after being finally overlapped twice.
Further, the pulse signal frequency f that single-chip microcontroller is arranged is twice of exciting signal frequency, and pulse signal is arranged
Pulsewidth P and delay Td makes Td=T-P/2, T be the period of pulse signal and T=1/f, the pulse signal frequency f=
10KHz, the pulsewidth P=20 μ s, the delay Td=90 μ s.
Further, pseudo- direct current signal is compensated including linear compensation and nonlinear compensation in the compensating unit.
Further, it is characterised in that the single-chip microcontroller is using C8051F061 single-chip microcontroller as master chip.
The present invention also has the advantages that
(1) software conditioning circuit is used, hardware circuit is simplified, so that system is more stable, more anti-interference be ensure that
System response.
(2) acquisition, conditioning, AD are settled at one go, improve the response speed of system, the requirement suitable for accurate measurement.
(3) hardware circuit simplified significantly reduces the volume of system, and whole system is made to become more portable, and cost is more
Inexpensively, production process is simpler.
Detailed description of the invention
Fig. 1 is that classical signal improves general flow chart and present invention conditioning schematic diagram comparison diagram；
Fig. 2 is the signal intensity figure during a kind of conditioning of custom circuit；
Fig. 3 is the corresponding waveform diagram of signal condition of the present invention；
Fig. 4 is flow diagram of the invention.
Specific embodiment
The following provides a specific embodiment of the present invention, it should be noted that the invention is not limited to implement in detail below
Example, all equivalent transformations made on the basis of the technical solutions of the present application each fall within protection scope of the present invention.
The technical term occurred in this programme is explained first:
Linear compensation: according to LVDT sensor output voltage values under positive and negative maximum range respectively, proportionality coefficient is obtained
K, and linear fit is carried out using K in positive and negative maximum range and zero crossings respectively；
Nonlinear compensation: voltage corresponding between the positive and negative maximum range of LVDT sensor is subjected to equal part and is different electricity
Pressure distribution different address space, and deviant is written in these address spaces, and be added with measurement result.
As shown in Fig. 2, traditional coordinating program that signal is carried out, for example, sensor exports the signal of a sine wave,
A half-wave is formed after amplifier, comparator and multidiameter option switch, is passing through a subtracter for sine wave and half-wave
After various operational amplifiers, a steamed bun wave is exported.In multiple feedback filter circuit by second order and some
A controllable direct current output will be obtained after necessary section filtering, the displacement of the voltage value and sensor of the output is linear
Relationship.This is arrived, the conditioning part of circuit is completed.Next output one high-order converter of access is obtained into digital letter
After number, computer that signal could be made a gift to someone is further processed.
Present embodiment discloses a kind of LVDT sensor signal processing methods for accurate measurement, without accessing high position AD
Converter includes the following steps:
Step 1: obtaining the analog signal of LVDT sensor output as pumping signal；
Step 2: frequency, pulsewidth and the delay of pulse signal are set according to pumping signal；
Step 3: the pumping signal that frequency, pulsewidth and the delay of the pulse signal obtained using step 2 obtain step 1 into
Row reconnaissance samples to obtain multiple sampled points, and smothing filtering is then overlapped and carried out to the signal amplitude of all sampled points, is obtained
To pseudo- direct current signal；Sampling process includes setting sampling time, sampling interval and number of sampling points, and the sampling time is by pulse signal
Number of cycles determine that the sampling interval determines by the cycle length of pulse signal；
Step 4: pseudo- direct current signal being compensated, smothing filtering, output digit signals are then passed through.
It is overlapped to the sampling of pumping signal and to the signal amplitude of all sampled points including following step in step 2
It is rapid:
Step a: respectively choosing q point to all wave crests in the pumping signal in the continuous n period and trough and complete sampling,
Middle n, q are positive integer；
Step b: being overlapped the range value of all wave crest sampled points, and the range value of all trough sampled points takes absolute value
After be overlapped, the summation of value after being finally overlapped twice.
Wherein, as shown in figure 3, sampling and superposition to the pumping signal progress in any period in n period include as follows
Step, wherein n=8, q=5:
Specifically, needing after the frequency of the pulse signal of setting single-chip microcontroller, pulsewidth and delay according to pumping signal and pulse
The relative phase of signal, is finely adjusted frequency and delay, when sensor reaches maximum range or slightly exceeding maximum range,
If pumping signal generates deformation, the signal peak for adjusting frequency to gamut is fallen into sample range, whenever frequency is modified
Afterwards, the peak value of pumping signal will deviate, and need to reset corresponding pulse delay；
In actual operation, when changing delay, signal can generate certain stretching, so that the position of Wave crest and wave trough
Phase shift occurs.Because after providing ideal delay time for the first time in software, needing to be adjusted it according to actual waveform.Adjustment
Method it is as follows:
Give the time delayed signal that will be read one read-write address first, such as 102；Then it is compared with multichannel oscillograph defeated
Signal and pulse signal out, stir sensor, as long as in gamut scope, the wave crest of output waveform all falls within the height of pulse signal
In level pulsewidth；Otherwise, memory Unit 102 is written into new delay parameter.
Specifically, the pulse signal frequency f of setting single-chip microcontroller is twice of exciting signal frequency, the arteries and veins of pulse signal is set
Wide P and delay Td makes Td=T-P/2, T be the period of pulse signal and T=1/f.
Preferably, the pulse signal frequency f=10KHz, the pulsewidth P=20 μ s, the delay Td90 μ s.
Specifically, compensating pseudo- direct current signal including linear compensation and nonlinear compensation in step 3.
As shown in figure 4, output 1 be output to the producer for debugging, as the foundation of compensation, output 2 is output to making
User is finally obtained measured value after compensation.
The present embodiment also discloses a kind of LVDT sensor signal processing system for accurate measurement, comprising: LVDT is passed
Sensor cell, pulse signal parameter set unit, sampling and superpositing unit and compensating unit；
The LVDT sensor unit is for exporting analog signal and passing it to excitation of the single-chip microcontroller as single-chip microcontroller
Signal；The pulse signal parameter set unit is used to be arranged according to pumping signal frequency, the pulsewidth of the pulse signal of single-chip microcontroller
And delay；The sampling and superpositing unit are used to sample pumping signal using the frequency, pulsewidth and delay of pulse signal,
Then smothing filtering is overlapped and carried out to the signal amplitude of all sampled points, obtains pseudo- direct current signal；The compensating unit
For being compensated to the pseudo- direct current signal of sampling and superpositing unit output, then carries out smothing filtering and obtain digital signal.
Specifically, sampling and superpositing unit include sampling subelement and superposition subelement；
The sampling subelement is used to respectively choose all wave crests in the pumping signal in the continuous n period and trough q
Point, wherein n, q are positive integer；
The superposition subelement is used to that being overlapped the range value of all wave crest sampled points of subelement output will to be sampled,
The range value of all trough sampled points is overlapped after taking absolute value, the value summation after being finally overlapped twice.
Specifically, the pulse signal frequency f of setting single-chip microcontroller is twice of exciting signal frequency, the arteries and veins of pulse signal is set
Wide P and delay Td makes Td=T-P/2, T be the period of pulse signal and T=1/f.
Preferably, the pulse signal frequency f=10KHz, the pulsewidth P=20 μ s, the delay Td90 μ s.
Specifically, compensating pseudo- direct current signal including linear compensation and nonlinear compensation in the compensating unit.
Specifically, the single-chip microcontroller is using C8051F061 single-chip microcontroller as master chip, the seldom entire electricity of component demand
Road plate only has 56cm*16cm size.Inexpensive is also convenient for producing.
This system can be applied to the accurate measurement of a variety of instruments, such as:
When measuring the internal diameter or outer diameter of axis, first axis is fixed, enables LVDT sensor contact with axis and is depressed into measurement range
It is interior, during axis rotation, (outer) diameter or minimum in (outer) diameter can be shown in maximum,
The Aout of axis standard component is measured first and passes through key zero setting, and after zero setting, system can keep in current value, and with sensing
The current location of device is zero point, then measures the current Aout value of other workpiece, calculates and saves before current Aout value and zero setting
Value is subtracted each other, and (outer) diameter at (outer) diameter or minimum is obtained in maximum.
Claims (10)
1. a kind of LVDT sensor signal processing method for accurate measurement, which comprises the steps of:
Step 1: obtaining the analog signal of LVDT sensor output as pumping signal；
Step 2: frequency, pulsewidth and the delay of pulse signal are set according to pumping signal；
Step 3: the pumping signal that frequency, pulsewidth and the delay of the pulse signal obtained using step 2 obtain step 1 is selected
Point sampling obtains multiple sampled points, and smothing filtering is then overlapped and carried out to the signal amplitude of all sampled points, obtains puppet
Direct current signal；
Step 4: pseudo- direct current signal being compensated, smothing filtering, output digit signals are then passed through.
2. being used for the LVDT sensor signal processing method of accurate measurement as described in claim 1, which is characterized in that step 2
In to pumping signal carry out reconnaissance sample to obtain multiple sampled points, then to the signal amplitude of all sampled points be overlapped including
Following steps:
Step a: respectively choosing q point to all wave crests in the pumping signal in the continuous n period and trough and complete sampling, wherein n,
Q is positive integer；
Step b: being overlapped the range value of all wave crest sampled points, and the range value of all trough sampled points takes absolute value laggard
Row superposition, the value summation after being finally overlapped twice.
3. being used for the LVDT sensor signal processing method of accurate measurement as claimed in claim 2, which is characterized in that described flat
Cunning is filtered into 2nThe smoothing processing of point.
4. being used for the LVDT sensor signal processing method of accurate measurement as described in claim 1, which is characterized in that setting is single
The pulse signal frequency f of piece machine is twice of exciting signal frequency, and the pulsewidth P and delay Td that pulse signal is arranged make Td=T-
P/2, T are the period of pulse signal and T=1/f.
5. being used for the LVDT sensor signal processing method of accurate measurement as described in claim 1, which is characterized in that step 3
In pseudo- direct current signal is compensated including linear compensation and nonlinear compensation.
6. a kind of LVDT sensor signal processing system for accurate measurement characterized by comprising LVDT sensor list
Member, pulse signal parameter set unit, sampling and superpositing unit and compensating unit；
The LVDT sensor unit is for exporting analog signal and passing it to pumping signal of the single-chip microcontroller as single-chip microcontroller；
The pulse signal parameter set unit is used to be arranged according to pumping signal the frequency of pulse signal of single-chip microcontroller, pulsewidth and prolongs
When；The sampling and superpositing unit are for sampling pumping signal using the frequency, pulsewidth and delay of pulse signal, then
Smothing filtering is overlapped and carried out to the signal amplitude of all sampled points, obtains pseudo- direct current signal；The compensating unit is used for
The pseudo- direct current signal of sampling and superpositing unit output is compensated, smothing filtering is then carried out and obtains digital signal.
7. as claimed in claim 6 be used for accurate measurement LVDT sensor signal processing system, which is characterized in that sampling and
Superpositing unit includes sampling subelement and superposition subelement；
The sampling subelement is used to respectively choose q point to all wave crests in the pumping signal in the continuous n period and trough,
Middle n, q are positive integer；
The superposition subelement is used to that being overlapped the range value of all wave crest sampled points of subelement output will to be sampled, and owns
The range value of trough sampled point is overlapped after taking absolute value, the value summation after being finally overlapped twice.
8. being used for the LVDT sensor signal processing system of accurate measurement as claimed in claim 6, which is characterized in that setting is single
The pulse signal frequency f of piece machine is twice of exciting signal frequency, and the pulsewidth P and delay Td that pulse signal is arranged make Td=T-
P/2, T are the period of pulse signal and T=1/f.
9. being used for the LVDT sensor signal processing system of accurate measurement as claimed in claim 6, which is characterized in that the benefit
It repays in unit and pseudo- direct current signal is compensated including linear compensation and nonlinear compensation.
10. being used for the LVDT sensor signal processing system of accurate measurement as claimed in claim 6, it is characterised in that the list
Piece machine is using C8051F061 single-chip microcontroller as master chip.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113515062A (en) * | 2020-04-11 | 2021-10-19 | 南京和邦智能科技有限公司 | High-precision LVDT measuring circuit and measuring method |
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Application publication date: 20191101 |