CN110631512A - External incident type angle sensing measuring device and method for bi-orthogonal plane mirror based on multi-longitudinal-mode self-mixing effect - Google Patents

External incident type angle sensing measuring device and method for bi-orthogonal plane mirror based on multi-longitudinal-mode self-mixing effect Download PDF

Info

Publication number
CN110631512A
CN110631512A CN201910940583.9A CN201910940583A CN110631512A CN 110631512 A CN110631512 A CN 110631512A CN 201910940583 A CN201910940583 A CN 201910940583A CN 110631512 A CN110631512 A CN 110631512A
Authority
CN
China
Prior art keywords
laser
plane mirror
longitudinal
angle
mode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN201910940583.9A
Other languages
Chinese (zh)
Other versions
CN110631512B (en
Inventor
吕亮
王晨辰
杨波
陈由泽
毕铁柱
周俊峰
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anhui University
Original Assignee
Anhui University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Anhui University filed Critical Anhui University
Priority to CN201910940583.9A priority Critical patent/CN110631512B/en
Publication of CN110631512A publication Critical patent/CN110631512A/en
Application granted granted Critical
Publication of CN110631512B publication Critical patent/CN110631512B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01BMEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00Measuring arrangements characterised by the use of optical techniques
    • G01B11/26Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)

Abstract

The application of the division relates to the technical field of optical measurement, in particular to a biorthogonal plane mirror external incidence type angle sensing measurement device and method based on a multi-longitudinal-mode self-mixing effect, wherein the device comprises a multi-longitudinal-mode laser, a sensing unit, a vibration target, a sliding device, a beam splitter, a photoelectric detector, a signal preprocessing unit and a signal processing unit; the sensing unit comprises a first rotating disc, a second rotating disc, a T-shaped transmission support, a first crossed plane mirror, a second crossed plane mirror, an orthogonal reflector and a reflector transmission support which are arranged side by side. The device has the advantages of simple structure, small volume and low cost, can realize non-contact real-time high-precision measurement, the sensing unit is a passive optical sensor, the power supply is not required, the light path of the testing device is a single light path, the environmental interference is small, the structure is simple, and the light path is convenient to adjust.

Description

External incident type angle sensing measuring device and method for bi-orthogonal plane mirror based on multi-longitudinal-mode self-mixing effect
The application is divisional application with application number 201810481300.4, application date 2018, 5, 18 and invention name 'angle sensing measuring device and method based on multi-longitudinal mode self-mixing effect'.
Technical Field
The invention relates to the technical field of optical measurement, in particular to a double-orthogonal plane mirror external incidence type angle sensing measurement device and method based on a multi-longitudinal-mode self-mixing effect.
Background
The angle measurement technology is an important component of the metering technology, and with the continuous development of the scientific technology, the angle measurement technology is widely applied to the technical fields of optical-mechanical-electrical integration, aerospace, military, national defense and the like.
The angle measurement technology mainly comprises a mechanical angle measurement technology, an electromagnetic angle measurement technology and an optical angle measurement technology. In the optical angle measurement technology, the interference angle measurement technology based on the laser self-mixing theory gradually becomes an important research object for high-precision angle measurement due to the advantages of a single optical path structure, auto-collimation and the like. However, the existing angle measuring device based on the laser self-mixing theory can only realize dynamic angle measurement and cannot be applied to measurement occasions where fixed angle measurement and quantitative measurement are required.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides an angle sensing measuring device and method capable of realizing fixed angle measurement and quantitative measurement based on a multi-longitudinal-mode self-mixing effect
In order to achieve the technical purpose, the technical scheme of the invention is as follows:
a biorthogonal plane mirror external incidence type angle sensing measuring device based on a multi-longitudinal-mode self-mixing effect comprises a multi-longitudinal-mode laser, a sensing unit, a vibration target, a sliding device, a beam splitter, a photoelectric detector, a signal preprocessing unit and a signal processing unit;
the sensing unit comprises a first rotating disc, a second rotating disc, a T-shaped transmission support, a first crossed plane mirror, a second crossed plane mirror, an orthogonal reflector and a reflector transmission support which are arranged side by side; the first turntable and the second turntable synchronously rotate through the T-shaped transmission bracket; the T-shaped transmission support comprises a first transmission rod and a support rod which are horizontally arranged and are perpendicular to each other, a first connecting column and a second connecting column are connected to two ends of the first transmission rod respectively, the bottom of the first connecting column and the bottom of the second connecting column are arranged on a first rotary table and a second rotary table respectively through bearings, the first transmission rod is parallel to a connecting line between the circle center of the first rotary table and the circle center of the second rotary table, and the middle part of the support rod is connected to the second connecting column; the first intersected plane mirror comprises a first plane mirror and a second plane mirror, one side of the first plane mirror is connected with one side of the second plane mirror, and the included angle between the mirror surface of the first plane mirror and the mirror surface of the second plane mirror is 90 degrees; the second intersecting plane mirror comprises a third plane mirror and a fourth plane mirror, one side of the third plane mirror is connected with one side of the fourth plane mirror, and the included angle between the third plane mirror and the fourth plane mirror is 90 degrees; the connecting edge of the first plane mirror and the second plane mirror and the connecting edge of the third plane mirror and the fourth plane mirror are respectively connected with the lower half parts of the two ends of the supporting rod, the angular bisector of the included angle between the first plane mirror surface and the second plane mirror surface and the angular bisector of the included angle between the third plane mirror surface and the fourth plane mirror surface are both vertical to the supporting rod, and the mirror surfaces of the first plane mirror, the second plane mirror, the third plane mirror and the fourth plane mirror are all deviated from the first transmission rod; the orthogonal reflector comprises a first reflector and a second reflector, one side of the first reflector is connected with one side of the second reflector, the included angle between the mirror surface of the first reflector and the mirror surface of the second reflector is 90 degrees, and the bisector of the included angle of the orthogonal reflector and the first transmission rod are positioned on the same straight line; the reflector transmission bracket comprises a second transmission rod and a third transmission rod which are symmetrically arranged, the bottom of one end of the second transmission rod is connected to the upper half part of one end of the support rod, the bottom of one end of the third transmission rod is connected to the upper half part of the other end of the support rod, the other end of the second transmission rod is connected with the other end of the third transmission rod, and the bottom of the joint of the first transmission rod and the third transmission rod is connected to the top of the joint of the first reflector and the second reflector;
the vibration target can vibrate, a reflection structure is attached to a vibration surface of the vibration target, the vibration target is located in front of the fourth plane mirror, an included angle between the vibration surface and the fourth plane mirror surface is 45 degrees, the bottom of the vibration target is fixed on the sliding device, the vibration target can move back and forth along the direction of the laser beam incident to the vibration surface by adjusting the sliding device, and the vibration surface and the laser beam incident to the vibration surface are always vertical in the moving process;
the multi-longitudinal-mode laser emits laser beams to the first plane mirror, and the included angle between the laser beams and the first plane mirror surface is 45 degrees;
the beam splitter is arranged between the multi-longitudinal-mode laser and the first plane mirror and is used for splitting a laser beam onto the photoelectric detector;
the photoelectric detector is used for converting the received laser signal into an electric signal and then sending the electric signal to the signal preprocessing unit;
the signal preprocessing unit is used for preprocessing the received electric signals, and the preprocessing at least comprises shaping, amplifying and filtering;
the signal processing unit is used for analyzing and processing the preprocessed electric signals to obtain the rotation angles of the first rotating disc and the second rotating disc to be tested.
As an improvement, an optical attenuator is also arranged between the multi-longitudinal mode laser and the beam splitter.
As an improvement, the sliding device comprises a sliding rail and a sliding block arranged on the sliding rail, and the bottom of the vibration target is fixed on the sliding block; the slide rail and the emergent laser are positioned on the same straight line;
as an improvement, the reflecting structure is a reflecting plane mirror or a reflecting film.
As a refinement, the vibration target is a speaker or a piezoelectric ceramic driven by a signal generator.
The angle measurement method of the bi-orthogonal plane mirror external incidence type angle sensing measurement device based on the multi-longitudinal mode self-mixing effect comprises the following steps: the vibration target vibrates, laser beams emitted by the multi-longitudinal-mode laser are incident on the vibration target through the sensing unit, the emitted laser is reflected by the reflecting structure and then fed back to the resonant cavity of the multi-longitudinal-mode laser along the original path to form a laser self-mixing signal, in the process, the turntable in the sensing unit rotates to cause the waveform of the laser self-mixing signal to change, the vibration target moves back and forth along the direction of the laser beams incident on the vibration surface by adjusting the sliding device, the vibration surface and the laser beams incident on the vibration surface are always kept vertical in the moving process to change the optical path of the vibration target from the multi-longitudinal-mode laser, so that the required laser self-mixing signals under different laser external cavity lengths are formed, the laser self-mixing signals under different laser external cavity lengths are collected by the photoelectric detector, and then the laser self-mixing signals are preprocessed by the signal preprocessing unit, and finally, analyzing the preprocessed laser self-mixing signals by using a signal processing unit to obtain the rotation angle of the turntable in the sensing unit, wherein the specific measurement and analysis method comprises the following steps:
for laser self-mixing signals of a multi-longitudinal-mode laser, different longitudinal modes of the laser only interfere with the self-mode, the finally formed laser self-mixing signals are laser self-mixing signal intensity superposition formed by the respective longitudinal modes, and according to a related interference mixing theory model, under the condition of not considering speckle influence, the multi-longitudinal-mode laser self-mixing signal intensity is obtained:
Figure BDA0002222753720000031
beta in the formula (1) is the total number of oscillation starting modes in the multi-longitudinal-mode laser, j represents the jth longitudinal mode in the laser, I0Is the initial light intensity,. DELTA.IjAmplitude of variation of light intensity of j-mode laser, phitjPhase, k, of the j-mode laser back and forth around the outer cavity0jWave number, op, of j mode in vacuumt(t) is the total optical path of real-time external cavity of the laser, c.c. represents the complex conjugate of the formula, and the calculationIn (1), the refractive index change caused by different longitudinal modes in the same material is negligible;
when the phase of the sensing unit changes, the external cavity total phase relationship is as follows:
phi in the formula (2)0jInitial phase of j-mode laser back and forth one revolution of the external cavity, delta phisjFor sensing unit phase change, delta phi, caused by rotation angle of the turntablecjFor compensating for phase changes, delta phi when measuring anglessj=-δφcj,op0Is the initial optical path of the external cavity of the laser, delta opsFor changes in the optical path of the sensing unit, delta op, caused by the angle of rotation of the turntablecTo compensate for optical path, ncIs the refractive index of air in the external cavity, and has a value of 1, nsIs the refractive index of the sensing unit, and has a constant value, LsFor the total geometrical length of the actual path of the laser light propagating in the sensor unit, LcTo compensate for the length;
Figure BDA0002222753720000042
in the formula (3) < omega >0Is the angular frequency of the laser, c is the speed of light in vacuum, ngIs the refractive index of the laser resonant cavity medium group, L0Is the laser resonant cavity length;
substituting formula (3) into formula (1) to obtain:
Figure BDA0002222753720000043
if the waveforms of the laser self-mixing signals of different modes are not separated, the waveforms of the modes need to keep the same phase or the phase delay is integral multiple of 2 pi:
φtj=k0jopt=2mk0jngL0=mφgjformula (5)
Namely:
opt=2mngL0formula (6)
In the formula (5), m is the external cavity mode order of the laser and is a positive integer phigjThe laser has a series of special position points for the phase of the laser which makes the laser self-mixing signal after being superimposed not generate waveform separation. As can be seen from equation (5), when the turntable rotates a certain angle, the phase of the light transmitted by the sensing unit changes, resulting in phi of each modetjChanging m value to make m no longer be integer, separating the waveform of the superposed laser self-mixing signal, regulating slide device to change vibration target position to compensate phase change, making the waveform of the superposed laser self-mixing signal become complete waveform, measuring vibration target position to obtain compensation phase change delta phicjFurther obtain the phase change delta phi of the sensing unit caused by the rotation angle of the rotary tablesjHere, the angle of rotation of the turntable causes a phase change δ φ in the sensing unitsjThe relationship of (a) is shown as follows:
Figure BDA0002222753720000051
in the formula (7)
Figure BDA0002222753720000052
Is the coefficient of variation of external optical path with angle, L, in the sensing units0For the total initial geometric length of the actual path of the laser light propagating in the sensor unit, ns0Is the refractive index of the sensing unit material;
using compensated phase in combination with sensing cell material refractive index ns0Total initial geometric length L of the actual path of the laser light propagating in the sensor units0The coefficient of variation of the external optical path in the sensing unit along with the angleAnd calculating to obtain the rotation angle of the rotary disc in the sensing unit.
From the above description, it can be seen that the present invention has the following advantages:
1. the sensing unit of the measuring device is a passive optical sensor, and power supply is not needed;
2. the test device has smaller volume and lower cost;
3. non-contact real-time high-precision measurement can be realized;
4. the optical path of the measuring device is a single optical path, the measuring device is small in environmental interference, simple in structure and convenient to adjust the optical path;
5. the sensitivity and resolution of angle measurement can be adjusted by designing parameters of the sensing unit and selecting different external cavity measuring tools.
Drawings
FIG. 1 is a schematic structural view of embodiment 1 of the present invention;
FIG. 2 is a schematic structural view of embodiment 1 of the present invention;
FIG. 3 is a schematic diagram of the optical path structure of an arbitrary-angle intersecting plane mirror in example 1 of the present invention;
FIG. 4 is a diagram showing simulation results of embodiment 1 of the present invention;
FIG. 5 is a diagram showing simulation results of embodiment 1 of the present invention;
FIG. 6 is a schematic structural view of embodiment 2 of the present invention;
FIG. 7 is a schematic structural view of embodiment 2 of the present invention;
FIG. 8 is a schematic diagram of the optical path structure of a single orthogonal plane mirror in example 2 of the present invention;
FIG. 9 is a schematic diagram of the optical path structure of a bi-orthogonal plane mirror in example 2 of the present invention;
fig. 10 is a diagram showing simulation results of embodiment 2 of the present invention.
Detailed Description
Embodiment 1 of the present invention is described in detail with reference to fig. 1 to 5, but the present invention is not limited to the claims.
As shown in fig. 1, an angle sensing and measuring device based on a multi-longitudinal-mode self-mixing effect includes a multi-longitudinal-mode laser 1, a sensing unit 2, a vibrating target 3, a sliding device 4, a beam splitter 5, a photodetector 6, a signal preprocessing unit 7 and a signal processing unit 8; the sensor unit 2 comprises a first turntable211. The second rotating disc 212, the transmission rod 213 and the intersecting plane mirror 214, the first rotating disc 211 and the second rotating disc 212 rotate synchronously through the transmission rod 213, the end parts of the two ends of the transmission rod 213 are respectively connected with the first connecting column 215 and the second connecting column 216, the bottom of the first connecting column 215 and the bottom of the second connecting column 216 are respectively arranged on the first rotating disc 211 and the second rotating disc 212 through bearings, the transmission rod 213 is parallel to the connecting line between the center of the first rotating disc 211 and the center of the second rotating disc 212, the intersecting plane mirror 214 comprises a first plane mirror 2141 and a second plane mirror 2142 with opposite mirror surfaces, one side of the first plane mirror 2141 is connected with one side of the second plane mirror 2142, the connecting sides of the first plane mirror 2141 and the second plane mirror 2142 are connected to the second connecting column 216, the mirror surfaces of the first plane mirror 2141 and the second plane mirror 2142 are both deviated from the transmission rod 213, the bisector of the included angle between the first plane, an included angle between the first plane mirror 2141 and the second plane mirror 2142 is denoted as α, and a value range of α is: 0 degree<α<180 degrees; the vibrating target 3 can vibrate, a reflecting structure is attached to the vibrating surface of the vibrating target 3, the vibrating target 3 is arranged outside the second plane mirror 2142, and the included angle between the vibrating surface and the mirror surface of the first plane mirror 2141 is equal to
Figure BDA0002222753720000061
The bottom of the vibration target 3 is fixed on a sliding device 4, the vibration target 3 can move back and forth along the direction of the laser beam incident on the vibration surface by adjusting the sliding device 4, and the vibration surface is always vertical to the laser beam incident on the vibration surface in the moving process; the multi-longitudinal-mode laser 1 emits laser beams onto the second plane mirror 2142, and the included angle between the laser beams and the second plane mirror 2142 is
Figure BDA0002222753720000071
The included angle formed by the laser beams emitted by the multi-longitudinal-mode laser 1 and the laser beams reflected by the second plane mirror 2142 is equal to alpha, and the included angle between the laser beams emitted by the multi-longitudinal-mode laser and the vibration surface of the vibration target is equal to alpha
Figure BDA0002222753720000072
The beam splitter 5 is arranged between the multi-longitudinal-mode laser 1 and the second plane mirror 2142 and is used for splitting the laser beam to the photoelectric detector 6; the photoelectric detector 6 is used for converting the received laser signal into an electric signal and then sending the electric signal to the signal preprocessing unit 7; the signal preprocessing unit 7 is used for preprocessing the received electric signals, and the preprocessing at least comprises shaping, amplifying and filtering; the signal processing unit 8 is configured to analyze the preprocessed electrical signals to obtain rotation angles of the first rotating disk 211 and the second rotating disk 212 to be tested.
The angle measuring method based on the measuring device comprises the following steps: the vibration target vibrates, the laser beam emitted by the multi-longitudinal mode laser is reflected to the second plane mirror, then reflected to the first plane mirror and then reflected to the vibration target, the laser beam incident to the vibration target is reflected by the reflection structure, the reflected beam is fed back to the resonant cavity of the multi-longitudinal mode laser along the original path to form a laser self-mixing signal, in the process, any rotating disc in the sensing unit rotates (the first rotating disc and the second rotating disc can synchronously rotate based on the arrangement of the transmission rod, when any rotating disc rotates, the transmission rod drives the other rotating disc to synchronously rotate), the intersecting plane mirror is driven to horizontally move to change the waveform of the laser self-mixing signal, the vibration target moves back and forth along the direction of the laser beam incident to the vibration surface by adjusting the sliding device, and the vibration surface and the laser beam incident to the vibration surface are always kept vertical in the moving process, the method comprises the following steps of changing the optical path of a multi-longitudinal-mode laser at a vibration target distance to form required laser self-mixing signals under different laser external cavity lengths, collecting the laser self-mixing signals under the different laser external cavity lengths by using a photoelectric detector, preprocessing the laser self-mixing signals by using a signal preprocessing unit, and analyzing the preprocessed laser self-mixing signals by using a signal processing unit to obtain the rotation angle of a turntable in a sensing unit, wherein the specific measurement and analysis method comprises the following steps:
for laser self-mixing signals of a multi-longitudinal-mode laser, different longitudinal modes of the laser only interfere with the self-mode, the finally formed laser self-mixing signals are laser self-mixing signal intensity superposition formed by the respective longitudinal modes, and according to a related interference mixing theory model, under the condition of not considering speckle influence, the multi-longitudinal-mode laser self-mixing signal intensity is obtained:
Figure BDA0002222753720000073
beta in the formula (1) is the total number of oscillation starting modes in the multi-longitudinal-mode laser, j represents the jth longitudinal mode in the laser, I0Is the initial light intensity,. DELTA.IjAmplitude of variation of light intensity of j-mode laser, phitjPhase, k, of the j-mode laser back and forth around the outer cavity0jWave number, op, of j mode in vacuumt(t) is the total optical path of the real-time external cavity of the laser, c.c. represents the complex conjugate of the formula, and the refractive index change caused by different longitudinal modes in the same material can be ignored in the calculation;
when the phase of the sensing unit changes, the external cavity total phase relationship is as follows:
Figure BDA0002222753720000081
phi in the formula (2)0jInitial phase of j-mode laser back and forth one revolution of the external cavity, delta phisjFor sensing unit phase change, delta phi, caused by rotation angle of the turntablecjFor compensating for phase changes, delta phi when measuring anglessj=-δφcj,op0Is the initial optical path of the external cavity of the laser, delta opsFor changes in the optical path of the sensing unit, delta op, caused by the angle of rotation of the turntablecTo compensate for optical path, ncIs the refractive index of air in the external cavity, and has a value of 1, nsIs the refractive index of the sensing unit, and has a constant value, LsFor the total geometrical length of the actual path of the laser light propagating in the sensor unit, LcTo compensate for the length;
Figure BDA0002222753720000082
in the formula (3) < omega >0Is the angular frequency of the laser and c is the light in vacuumSpeed, ngIs the refractive index of the laser resonant cavity medium group, L0Is the laser resonant cavity length;
substituting formula (3) into formula (1) to obtain:
Figure BDA0002222753720000083
if the waveforms of the laser self-mixing signals of different modes are not separated, the waveforms of the modes need to keep the same phase or the phase delay is integral multiple of 2 pi:
φtj=k0jopt=2mk0jngL0=mφgjformula (5)
Namely:
opt=2mngL0formula (6)
In the formula (5), m is the external cavity mode order of the laser and is a positive integer phigjThe laser has a series of special position points for the phase of the laser which makes the laser self-mixing signal after being superimposed not generate waveform separation. As can be seen from equation (5), when the turntable rotates a certain angle, the phase of the light transmitted by the sensing unit changes, resulting in phi of each modetjChanging m value to make m no longer be integer, separating the waveform of the superposed laser self-mixing signal, regulating slide device to change vibration target position to compensate phase change, making the waveform of the superposed laser self-mixing signal become complete waveform, measuring vibration target position to obtain compensation phase change delta phicjFurther obtain the phase change delta phi of the sensing unit caused by the rotation angle of the rotary tablesjHere, the angle of rotation of the turntable causes a phase change δ φ in the sensing unitsjThe relationship of (a) is shown as follows:
Figure BDA0002222753720000091
in the formula (7)
Figure BDA0002222753720000092
Is the coefficient of variation of external optical path with angle, L, in the sensing units0For the total initial geometric length of the actual path of the laser light propagating in the sensor unit, ns0Is the refractive index of the sensing unit material;
using compensated phase in combination with sensing cell material refractive index ns0Total initial geometric length L of the actual path of the laser light propagating in the sensor units0The coefficient of variation of the external optical path in the sensing unit along with the angleAnd calculating to obtain the rotation angle of the rotary disc in the sensing unit.
The external cavity change sensitivity S of the angle sensor can be further obtained by the formula (7)mLcAnd adjacent order angle difference delta thetam. Wherein the external cavity variation sensitivity SmLcMeans the length change of the compensation external cavity caused by the change of unit angle and the angle difference delta theta of adjacent levelmRefers to the angle theta2Position (m +1 level) and angle theta of external cavity equiphase point caused by (after change)1And (before change) the adjacent-level angle difference corresponding to the position (m level) of the external cavity equiphase point. In general, in the angle measurement process, if the measured angle difference in two consecutive measurement intervals is greater than the adjacent-stage angle difference Δ θmThe number of cycles of the waveform change of the self-mixing signal, i.e. the change of the value m, in two consecutive measurement intervals is recorded, and the length of the compensation external cavity is adjusted to restore the waveform of the laser self-mixing signal to the position where the waveform of the signal corresponding to the mth level coincides.
The external cavity variation sensitivity S is expressed by the formulas (8) and (9), respectivelymLcAnd adjacent order angle difference delta thetamExpression:
Figure BDA0002222753720000101
Figure BDA0002222753720000102
in the above measurement and analysis method, the analysis method of the relationship between the external optical path of the sensing unit and the angle change is as follows:
as shown in fig. 2, a start position O2V (i.e. the center O of the second turntable)2A line connecting the fixed points V of the intersecting plane mirrors) is parallel to the y-axis, and when the rotation angle of the first rotating disc 1 is theta
Figure BDA0002222753720000103
The second turntable 2 rotates by the same angle, and the transmission rod is always parallel to the x axis to ensure that the intersecting plane mirror does not deviate in the vertical direction and only generates translation in the xy plane. After the rotation, the first plane mirror and the second plane mirror are both crossed and shifted, the laser 1 emits laser through the point A, in the whole rotation process, the position of the laser 1 is always kept at the point A, light rays are reflected by the plane mirror and the reflector for multiple times and then return from the point D along the original path, and the radiuses of the first rotary disc and the second rotary disc are both R.
Based on the angle measurement system with the single-intersection plane mirror, the optical path change of the angle measurement system is theoretically calculated, a single intersection plane mirror structure diagram with any included angle as shown in figure 3 is established, and the vertex V of the intersection plane mirror1Reaches V after rotating2Primary light path AB1C1D1Become AB2C2D2The optical path difference can be derived as follows:
Figure BDA0002222753720000104
wherein,
Figure BDA0002222753720000105
geometrically derived:
the optical path difference caused by the angle change can be expressed as:
Figure BDA0002222753720000111
substituting equation (7) yields:
Figure BDA0002222753720000112
combining the formula (12), it can be known that the optical path difference is related to the included angle α between the two mirror surfaces and the rotation angle θ of the turntable, and the included angle between the special mirror surfaces is simplified as follows for the simplified equation:
(1) when the included angle alpha of the two mirror surfaces is 90 degrees, namely the two mirror surfaces are vertical, the optical path difference can be obtained:
ΔL=-4Rsinθ (14)
in this case, formula (14) is substituted into formulae (7), (8), and (9) to obtain:
δφsj=k0jns0|-4Rsinθ|=-k0jδ(ncLc)=-δφcj (15)
Figure BDA0002222753720000113
Figure BDA0002222753720000114
the experimental device is established based on the technical scheme, the experimental device adopts the dual-mode LD laser as a light source, simulation software is utilized for analog simulation, and for simplicity, only the intensity superposition waveform of the dual-mode LD laser self-mixing signal with the same amplitude is considered. The simulation results are shown in fig. 4. As can be seen from FIG. 4, when the angle is 0, the initial external cavity optical length of the laser is 1050mm and ngL0M is 1000, and the laser self-mixing signal waveform is not separated. When the angle of the sensing unit increases
Figure BDA0002222753720000115
When the phase of a sensing unit is slightly changed, the waveform of overlapped laser self-mixing signals is separated, the length of a fine-tuning compensation external cavity is 18.15mm, and the external cavity phase of the laser becomes phi againgM is 1000, the superposed laser beam disappears from the mixed signal waveform separately, and the laser beam passes throughAnd finally, the change of the corresponding angle of the sensing unit is obtained by measuring the compensation phase, so that the rotation angle of the turntable of the sensing unit is measured.
(2) When the included angle α of the mirror surface is 60 °, the optical path difference can be obtained:
Figure BDA0002222753720000121
in this case, by substituting equation (18) into equations (7), (8), and (9):
Figure BDA0002222753720000122
Figure BDA0002222753720000123
Figure BDA0002222753720000124
the experimental device is established based on the technical scheme, the experimental device adopts the dual-mode LD laser as a light source, simulation software is utilized for analog simulation, and for simplicity, only the intensity superposition waveform of the dual-mode LD laser self-mixing signal with the same amplitude is considered. The simulation diagram is shown in fig. 5. As can be seen from FIG. 5, when the angle is 0, the initial external cavity optical length of the laser is 1050mm and ngL0M is 1000, and the laser self-mixing signal waveform is not separated. When the angle of the sensing unit increases
Figure BDA0002222753720000125
When the laser self-mixing signal waveform is separated, the length of a fine-tuning compensation external cavity is 0.28mm, and the external cavity phase of the laser becomes phi againgThe overlapped laser wave shape disappears separately from the mixed signal wave shape, and finally the change of the corresponding sensing unit angle is obtained by measuring the compensation phase, thereby realizing the measurement of the rotating angle of the sensing unit turntable.
It can be seen from the derivation process that, compared with the conventional laser self-mixing angle measurement method, the incident type self-mixing angle measurement system and measurement method in the single arbitrary angle intersection plane mirror described in this embodiment have the advantages that the angle measurement range is not limited, and the system resolution is higher.
As can be seen from the above description, the present embodiment has the following advantages:
1. the sensing unit of the measuring device is a passive optical sensor, and power supply is not needed;
2. the test device has smaller volume and lower cost;
3. non-contact real-time high-precision measurement can be realized;
4. the optical path of the measuring device is a single optical path, the measuring device is small in environmental interference, simple in structure and convenient to adjust the optical path;
5. the sensitivity and the resolution of angle measurement can be adjusted by designing and selecting different external cavity measuring tools through parameters of the sensing unit;
6. the structure of the sensing unit is as follows: (1) when laser beams are incident to the intersecting plane mirrors, the laser beams are firstly incident to the second plane mirror on the inner side, namely, an internal incidence mode is adopted, so that the overall structure of the measuring system is compact; (2) through the reflection unit formed by the intersecting plane mirror and the vibration target, the auto-collimation of the laser self-mixing signal is realized, and compared with the reflection unit formed by the traditional plane mirror or the reflection unit formed by a right-angle prism, the optical path difference of the laser self-mixing signal is increased before and after rotation under the same rotation angle, so that the measurement resolution and the measurement range of the system are improved; (3) the whole structure of the measuring system is simple and easy to realize, the mechanical error is small, the included angle between the first plane mirror and the second plane mirror is adjustable, different angles correspond to different system measurement resolutions, and the included angle can be selected according to actual requirements.
Embodiment 2 of the present invention will be described in detail with reference to fig. 6 to 10, but the present invention is not limited to the claims.
As shown in fig. 6, an angle sensing and measuring device based on a multi-longitudinal-mode self-mixing effect includes a multi-longitudinal-mode laser 1, a sensing unit 2, a vibrating target 3, a sliding device 4, a beam splitter 5, a photodetector 6, a signal preprocessing unit 7, and a signal processing unit 8; the sensing unit 2 comprises a first rotary table 221 and a second rotary table 222 which are arranged side by side, a T-shaped transmission support, a first intersecting plane mirror, a second intersecting plane mirror, an orthogonal reflector and a reflector transmission support, wherein the first rotary table 221 and the second rotary table 222 synchronously rotate through the T-shaped transmission support 223, the T-shaped transmission support comprises a first transmission rod 2231 and a support rod 2232 which are horizontally arranged and perpendicular to each other, two ends of the first transmission rod 2231 are respectively connected with a first connecting column 228 and a second connecting column 229, the bottom of the first connecting column 228 and the bottom of the second connecting column 229 are respectively arranged on the first rotary table 221 and the second rotary table 222 through bearings, the first transmission rod 2231 is parallel to a connecting line between the circle center of the first rotary table 221 and the circle center of the second rotary table 222, the middle part of the support rod 2232 is connected to the second connecting column 229, the first intersecting plane mirror comprises a first plane mirror 2241 and a second plane mirror 2242, one side of the first plane mirror 2241 is connected with one side of the second plane mirror 2242, and the included angle of the planes is 90 °, the second intersecting plane mirror comprises a third plane mirror 2251 and a fourth plane mirror 2252, one side of the third plane mirror 2251 is connected to one side of the fourth plane mirror 2252 and the included angle between the mirror surface of the third plane mirror 2251 and the mirror surface of the fourth plane mirror 2252 is 90 °, the connecting edge of the first plane mirror 2241 and the second plane mirror 2242 and the connecting edge of the third plane mirror 2251 and the fourth plane mirror 2252 are connected to the lower half parts of both ends of the supporting bar 2232, the bisector of the included angle between the mirror surface of the first plane mirror 2241 and the second plane mirror 2242 and the bisector of the included angle between the mirror surface of the third plane mirror 2251 and the mirror surface of the fourth plane mirror 2252 are perpendicular to the supporting bar 2232, the mirror surfaces of the first plane mirror 2261, the second plane mirror 2242, the third plane mirror 2251 and the fourth plane mirror 2252 are all away from the first transmission bar 2231, the orthogonal mirror comprises a first mirror 1 and a second mirror 2262, one side of the first mirror 2261 is connected to one side of the second mirror 2262 and the third mirror 2252 The angle is 90 degrees, the bisector of the included angle is positioned on the same straight line with the first transmission rod 2231, the reflector transmission bracket comprises a second transmission rod 2271 and a third transmission rod 2272 which are symmetrically arranged, the bottom of one end of the second transmission rod 2271 is connected to the upper half part of one end of the support rod 2232, the bottom of one end of the third transmission rod 2272 is connected to the upper half part of the other end of the support rod 2232, the other end of the second transmission rod 2271 is connected with the other end of the third transmission rod 2272, and the bottom of the joint of the first reflector 2261 and the second reflector 2262 is connected to the top of the joint of the first reflector 2261 and; the vibration target 3 can vibrate, a reflection structure is attached to a vibration surface of the vibration target 3, the vibration target 3 is located in front of the fourth plane mirror 2252, an included angle between the vibration surface and the mirror surface of the fourth plane mirror 2252 is 45 degrees, the bottom of the vibration target 3 is fixed on the sliding device 4, the vibration target can move back and forth along the direction of the laser beam incident on the vibration surface by adjusting the sliding device 4, and the vibration surface and the laser beam incident on the vibration surface are always kept perpendicular in the moving process; the multi-longitudinal-mode laser 1 emits laser beams to the first plane mirror, and the included angle between the laser beams and the first plane mirror is 45 degrees; the beam splitter 5 is arranged between the multi-longitudinal-mode laser and the first plane mirror 2241 and is used for splitting a laser beam onto the photoelectric detector 6; the photoelectric detector 6 is used for converting the received laser signal into an electric signal and then sending the electric signal to the signal preprocessing unit 7; the signal preprocessing unit 7 is used for preprocessing the received electric signals, and the preprocessing at least comprises shaping, amplifying and filtering; the signal processing unit 8 is used for analyzing and processing the preprocessed electric signals to obtain the rotation angles of the first rotating disk and the second rotating disk to be tested.
The angle measuring method based on the measuring device comprises the following steps: the vibration target vibrates, the laser beam emitted by the multi-longitudinal mode laser enters a first plane mirror at an angle of 45 degrees, the laser beam is reflected to a first reflecting mirror through a second plane mirror, the first reflecting mirror reflects the laser beam to a second reflecting mirror and then is reflected to a third plane mirror through a second reflecting mirror, the direction of the laser beam entering the third plane mirror is the same as the direction of the laser beam emitted by the laser, the included angle between the laser beam and the third plane mirror is 45 degrees, the laser beam is sequentially reflected through the third plane mirror and the fourth plane mirror which are vertical to each other and then enters the vibration target at an angle of 90 degrees, the laser beam entering the vibration target is opposite to the direction of the laser beam emitted by the laser and is reflected by a reflecting structure, the reflected beam is fed back to the multi-longitudinal mode resonant cavity along the original path to form a laser self-mixing signal, in the process, any rotary disc in the sensing unit rotates (based on the arrangement of a T-shaped transmission bracket, when any one turntable rotates, the T-shaped transmission bracket drives the other turntable to synchronously rotate) to drive the first intersecting plane mirror and the second intersecting plane mirror to horizontally move, so that the waveform of the laser self-mixing signal is changed, the vibration target is moved back and forth along the direction of the laser beam incident on the vibration surface by adjusting the sliding device, the vibration surface and the laser beam incident on the vibration surface are always vertical in the moving process to change the optical path of the vibration target from the multi-longitudinal-mode laser, so that the required laser self-mixing signals under different laser external cavity lengths are formed, the laser self-mixing signals under different laser external cavity lengths are collected by the photoelectric detector, then the laser self-mixing signals are preprocessed by the signal preprocessing unit, and finally the preprocessed laser self-mixing signals are analyzed by the signal processing unit, the rotation angle of the rotary disc in the sensing unit can be obtained.
The specific measurement and analysis method of this embodiment is the same as the measurement and analysis method in embodiment 1, and referring to the analysis processes from formula (1) to formula (9), the difference between this embodiment and embodiment 1 is only that the specific structure of the sensing unit is different, so that the relationship between the external optical path and the angle change of the sensing unit in this embodiment is different from the relationship in embodiment 1.
In this embodiment, the method for analyzing the relationship between the external optical path of the sensing unit and the angle change is as follows:
as shown in FIG. 7, a start position P1P2(first intersecting plane mirror vertex P1Vertex P of plane mirror intersecting with second phase2Is parallel to the y-axis, when the first rotation angle is theta
Figure BDA0002222753720000151
The second turntable 2 rotates by the same angle, and the T-shaped transmission support is always parallel to the x axis to ensure that the first intersected plane mirror and the second intersected plane mirror do not deviate in the vertical direction and only generate translation in the xy plane. After rotating, the first plane mirror and the second plane mirrorThe surface mirror, the third plane mirror and the fourth plane mirror are mutually orthogonal and offset, the laser 1 emits laser from the point A, the position of the laser 1 is always kept at the point A in the whole rotating process, light rays are returned from the point H along the original path after being reflected by the plane mirror and the reflecting mirror for multiple times, and the radiuses of the first rotary table and the second rotary table are both R. The first intersecting plane mirror and the second intersecting plane mirror are orthogonal plane mirrors due to the fact that the included angle is 90 degrees.
Based on the angle measurement system with the double orthogonal plane mirrors, the optical path change of the angle measurement system is theoretically calculated, the experimental device is simplified, and the structural diagram of the single orthogonal plane mirror shown in fig. 8 is established.
As shown in FIG. 8, the vertex V of the orthogonal plane mirror1Reaches V after rotating2Primary light path AB1C1D1Become AB2C2D2The optical path difference can be derived from the geometrical relationship as follows:
Figure BDA0002222753720000161
the optical path difference caused by the angle change can be expressed as:
therefore, for the angle measurement system with the biorthogonal plane mirrors described in this embodiment, as shown in fig. 9, the optical path difference can be calculated as:
Figure BDA0002222753720000163
when the optical path of the feedback light changes one wavelength each time the laser changes one stripe from the mixed waveform, the following can be obtained:
in this case, by substituting equation (24) into equations (7), (8), and (9):
δφsj=k0jns0|2R(2sinθ-cosθ+1)|=-k0jδ(ncLc)=-δφcj (25)
Figure BDA0002222753720000164
the experimental device is established based on the technical scheme, the experimental device adopts the dual-mode LD laser as a light source, simulation software is utilized for analog simulation, and for simplicity, only the intensity superposition waveform of the dual-mode LD laser self-mixing signal with the same amplitude is considered. The simulation diagram is shown in fig. 10. As can be seen from FIG. 10, when the angle is 0, the external cavity initial optical path of the laser is 1050mm and ngL0M is 1000, and the laser self-mixing signal waveform is not separated. When the angle of the sensing unit increases
Figure BDA0002222753720000166
When the phase of the sensing unit slightly changes, the overlapped laser self-mixing signal waveform is separated, the length of the fine-tuning compensation external cavity is 13.34mm, and the external cavity phase of the laser becomes phi againgThe overlapped laser wave shape disappears separately from the mixed signal wave shape, and finally the change of the corresponding sensing unit angle is obtained by measuring the compensation phase, thereby realizing the measurement of the rotating angle of the sensing unit turntable.
As can be seen from the derivation process, compared with the conventional laser self-mixing angle measurement method, the system and the method for measuring the external incidence type laser self-mixing angle of the dual-orthogonal plane mirror described in this embodiment have the advantages that the angle measurement range is not limited, and the system resolution is higher.
As can be seen from the above description, the present embodiment has the following advantages:
1. the sensing unit of the measuring device is a passive optical sensor, and power supply is not needed;
2. the test device has smaller volume and lower cost;
3. non-contact real-time high-precision measurement can be realized;
4. the optical path of the measuring device is a single optical path, the measuring device is small in environmental interference, simple in structure and convenient to adjust the optical path;
5. the sensitivity and the resolution of angle measurement can be adjusted by designing and selecting different external cavity measuring tools through parameters of the sensing unit;
6. the structure of the sensing unit is as follows: (1) when a laser beam is incident on the first intersecting plane mirror, the laser beam is firstly incident on the first plane mirror at the outer side, namely, an external incidence mode is adopted, and compared with a traditional heterodyne interference system, the system structure is simpler; (2) through the reflection unit that first crossing plane mirror, first speculum, second crossing plane mirror and vibration target constitute, not only realized the auto-collimation of laser self-mixing signal but also compare in the reflection unit that the reflection unit or the right-angle prism that traditional level mirror constitute, under same turned angle, before and after the rotation, the optical path difference grow of laser self-mixing signal to the measurement resolution ratio and the measuring range of system have been improved.
In the two embodiments, the measuring device may be optimized or improved as follows:
1. preferably, in an embodiment with two rotating discs, a driving belt is sleeved on the first rotating disc and the second rotating disc, and the two rotating discs rotate synchronously through the driving belt;
2. preferably, the sliding device 4 includes a sliding rail 41 and a sliding block 42 disposed on the sliding rail 41, and the bottom of the vibration target is fixed on the sliding block 42; the slide rail 41 is in the same straight line with the direction of the laser beam incident to the vibration surface of the vibration target;
3. preferably, the reflecting structure may be a reflecting plane mirror, or may be a material having scattering properties or reflecting properties, such as a reflecting film;
4. preferably, the vibration target 3 can adopt a loudspeaker 32 driven by a signal generator 31 or piezoelectric ceramics, two loudspeakers 32 in fig. 1 and 6 respectively represent the positions of the loudspeaker before and after sliding along the sliding device;
5. preferably, the signal processing unit 8 may be a computer, an oscilloscope or a spectrometer;
6. in an improved mode, an optical attenuator 218 is additionally arranged between the multi-longitudinal-mode laser and the beam splitter, the optical attenuator 218 is used for adjusting the light intensity of feedback light received by the laser, and the feedback light is prevented from being too strong or exceeding a laser damage threshold, so that the accuracy of a measurement result is further ensured, and the optical attenuator can be a displacement type attenuator, an attenuation sheet type attenuator or other types of optical attenuators;
7. in the improved mode, the multi-longitudinal-mode laser 1 adopts a semiconductor laser, and integrates a photodiode in the semiconductor laser by utilizing the characteristics of the semiconductor laser to realize the function of the photoelectric detector, thereby simplifying the optical path of the whole device and removing a beam splitter and the photoelectric detector.
In summary, the invention has the following advantages:
1. the sensing unit of the measuring device is a passive optical sensor, and power supply is not needed;
2. the test device has smaller volume and lower cost;
3. non-contact real-time high-precision measurement can be realized;
4. the optical path of the measuring device is a single optical path, the measuring device is small in environmental interference, simple in structure and convenient to adjust the optical path;
5. the sensitivity and the resolution of angle measurement can be adjusted by designing and selecting different external cavity measuring tools through parameters of the sensing unit;
6. the optical path structure of the sensing unit is selected variously, and the sensing unit with corresponding characteristics can be selected according to specific requirements.
It should be understood that the detailed description of the invention is merely illustrative of the invention and is not intended to limit the invention to the specific embodiments described. It will be appreciated by those skilled in the art that the present invention may be modified or substituted equally as well to achieve the same technical result; as long as the use requirements are met, the method is within the protection scope of the invention.

Claims (6)

1. The utility model provides a biorthogonal level crossing external incidence type angle sensing measuring device based on many longitudinal modes are from mixing effect which characterized in that: the device comprises a multi-longitudinal-mode laser, a sensing unit, a vibration target, a sliding device, a beam splitter, a photoelectric detector, a signal preprocessing unit and a signal processing unit;
the sensing unit comprises a first rotating disc, a second rotating disc, a T-shaped transmission support, a first crossed plane mirror, a second crossed plane mirror, an orthogonal reflector and a reflector transmission support which are arranged side by side; the first turntable and the second turntable synchronously rotate through the T-shaped transmission bracket; the T-shaped transmission support comprises a first transmission rod and a support rod which are horizontally arranged and are perpendicular to each other, a first connecting column and a second connecting column are connected to two ends of the first transmission rod respectively, the bottom of the first connecting column and the bottom of the second connecting column are arranged on a first rotary table and a second rotary table respectively through bearings, the first transmission rod is parallel to a connecting line between the circle center of the first rotary table and the circle center of the second rotary table, and the middle part of the support rod is connected to the second connecting column; the first intersected plane mirror comprises a first plane mirror and a second plane mirror, one side of the first plane mirror is connected with one side of the second plane mirror, and the included angle between the mirror surface of the first plane mirror and the mirror surface of the second plane mirror is 90 degrees; the second intersecting plane mirror comprises a third plane mirror and a fourth plane mirror, one side of the third plane mirror is connected with one side of the fourth plane mirror, and the included angle between the third plane mirror and the fourth plane mirror is 90 degrees; the connecting edge of the first plane mirror and the second plane mirror and the connecting edge of the third plane mirror and the fourth plane mirror are respectively connected with the lower half parts of the two ends of the supporting rod, the angular bisector of the included angle between the first plane mirror surface and the second plane mirror surface and the angular bisector of the included angle between the third plane mirror surface and the fourth plane mirror surface are both vertical to the supporting rod, and the mirror surfaces of the first plane mirror, the second plane mirror, the third plane mirror and the fourth plane mirror are all deviated from the first transmission rod; the orthogonal reflector comprises a first reflector and a second reflector, one side of the first reflector is connected with one side of the second reflector, the included angle between the mirror surface of the first reflector and the mirror surface of the second reflector is 90 degrees, and the bisector of the included angle of the orthogonal reflector and the first transmission rod are positioned on the same straight line; the reflector transmission bracket comprises a second transmission rod and a third transmission rod which are symmetrically arranged, the bottom of one end of the second transmission rod is connected to the upper half part of one end of the support rod, the bottom of one end of the third transmission rod is connected to the upper half part of the other end of the support rod, the other end of the second transmission rod is connected with the other end of the third transmission rod, and the bottom of the joint of the first transmission rod and the third transmission rod is connected to the top of the joint of the first reflector and the second reflector;
the vibration target can vibrate, a reflection structure is attached to a vibration surface of the vibration target, the vibration target is located in front of the fourth plane mirror, an included angle between the vibration surface and the fourth plane mirror surface is 45 degrees, the bottom of the vibration target is fixed on the sliding device, the vibration target can move back and forth along the direction of the laser beam incident to the vibration surface by adjusting the sliding device, and the vibration surface and the laser beam incident to the vibration surface are always vertical in the moving process;
the multi-longitudinal-mode laser emits laser beams to the first plane mirror, and the included angle between the laser beams and the first plane mirror surface is 45 degrees;
the beam splitter is arranged between the multi-longitudinal-mode laser and the first plane mirror and is used for splitting a laser beam onto the photoelectric detector;
the photoelectric detector is used for converting the received laser signal into an electric signal and then sending the electric signal to the signal preprocessing unit;
the signal preprocessing unit is used for preprocessing the received electric signals, and the preprocessing at least comprises shaping, amplifying and filtering;
the signal processing unit is used for analyzing and processing the preprocessed electric signals to obtain the rotation angles of the first rotating disc and the second rotating disc to be tested.
2. The bi-orthogonal plane mirror external incidence type angle sensing measuring device based on the multi-longitudinal mode self-mixing effect as claimed in claim 1, wherein: and an optical attenuator is also arranged between the multi-longitudinal-mode laser and the beam splitter.
3. The bi-orthogonal plane mirror external incidence type angle sensing measuring device based on the multi-longitudinal mode self-mixing effect as claimed in claim 1, wherein: the sliding device comprises a sliding rail and a sliding block arranged on the sliding rail, and the bottom of the vibration target is fixed on the sliding block; the slide rail and the emergent laser are positioned on the same straight line.
4. The bi-orthogonal plane mirror external incidence type angle sensing measuring device based on the multi-longitudinal mode self-mixing effect as claimed in claim 1, wherein: the reflecting structure is a reflecting plane mirror or a reflecting film.
5. The bi-orthogonal plane mirror external incidence type angle sensing measuring device based on the multi-longitudinal mode self-mixing effect as claimed in claim 1, wherein: the vibration target is a speaker or a piezoelectric ceramic driven by a signal generator.
6. The angle measurement method of the bi-orthogonal plane mirror external incidence type angle sensing measurement device based on the multi-longitudinal mode self-mixing effect as claimed in claim 1, wherein: the vibration target vibrates, laser beams emitted by the multi-longitudinal-mode laser are incident on the vibration target through the sensing unit, the emitted laser is reflected by the reflecting structure and then fed back to the resonant cavity of the multi-longitudinal-mode laser along the original path to form a laser self-mixing signal, in the process, the turntable in the sensing unit rotates to cause the waveform of the laser self-mixing signal to change, the vibration target moves back and forth along the direction of the laser beams incident on the vibration surface by adjusting the sliding device, the vibration surface and the laser beams incident on the vibration surface are always kept vertical in the moving process to change the optical path of the vibration target from the multi-longitudinal-mode laser, so that the required laser self-mixing signals under different laser external cavity lengths are formed, the laser self-mixing signals under different laser external cavity lengths are collected by the photoelectric detector, and then the laser self-mixing signals are preprocessed by the signal preprocessing unit, and finally, analyzing the preprocessed laser self-mixing signals by using a signal processing unit to obtain the rotation angle of the turntable in the sensing unit, wherein the specific measurement and analysis method comprises the following steps:
for laser self-mixing signals of a multi-longitudinal-mode laser, different longitudinal modes of the laser only interfere with the self-mode, the finally formed laser self-mixing signals are laser self-mixing signal intensity superposition formed by the respective longitudinal modes, and according to a related interference mixing theory model, under the condition of not considering speckle influence, the multi-longitudinal-mode laser self-mixing signal intensity is obtained:
Figure FDA0002222753710000031
beta in the formula (1) is the total number of oscillation starting modes in the multi-longitudinal-mode laser, j represents the jth longitudinal mode in the laser, I0Is the initial light intensity,. DELTA.IjAmplitude of variation of light intensity of j-mode laser, phitjPhase, k, of the j-mode laser back and forth around the outer cavity0jWave number, op, of j mode in vacuumt(t) is the total optical path of the real-time external cavity of the laser, c.c. represents the complex conjugate of the formula, and the refractive index change caused by different longitudinal modes in the same material can be ignored in the calculation;
when the phase of the sensing unit changes, the external cavity total phase relationship is as follows:
Figure FDA0002222753710000032
phi in the formula (2)0jInitial phase of j-mode laser back and forth one revolution of the external cavity, delta phisjFor sensing unit phase change, delta phi, caused by rotation angle of the turntablecjFor compensating for phase changes, delta phi when measuring anglessj=-δφcj,op0Is the initial optical path of the external cavity of the laser, delta opsFor changes in the optical path of the sensing unit, delta op, caused by the angle of rotation of the turntablecTo compensate for optical path, ncIs the refractive index of air in the external cavity, and has a value of 1, nsIs the refractive index of the sensing unit, and has a constant value, LsFor the total geometrical length of the actual path of the laser light propagating in the sensor unit, LcTo compensate for the length;
Figure FDA0002222753710000033
in the formula (3) < omega >0Is the angular frequency of the laser, c is the speed of light in vacuum, ngIs the refractive index of the laser resonant cavity medium group, L0Is the laser resonant cavity length;
substituting formula (3) into formula (1) to obtain:
if the waveforms of the laser self-mixing signals of different modes are not separated, the waveforms of the modes need to keep the same phase or the phase delay is integral multiple of 2 pi:
φtj=k0jopt=2mk0jngL0=mφgjformula (5)
Namely:
opt=2mngL0formula (6)
In the formula (5), m is the external cavity mode order of the laser and is a positive integer phigjThe phase of the laser is round trip in the resonant cavity of the laser, so the laser has a series of special position points, the superposed laser self-mixing signal does not generate waveform separation, and as can be known from the formula (5), when the turntable rotates a certain angle, the phase of the light in the transmission of the sensing unit changes, which results in phi of each modetjChanging m value to make m no longer be integer, separating the waveform of the superposed laser self-mixing signal, regulating slide device to change vibration target position to compensate phase change, making the waveform of the superposed laser self-mixing signal become complete waveform, measuring vibration target position to obtain compensation phase change delta phicjFurther obtain the phase change delta phi of the sensing unit caused by the rotation angle of the rotary tablesjHere, the angle of rotation of the turntable causes a phase change δ φ in the sensing unitsjThe relationship of (a) is shown as follows:
Figure FDA0002222753710000042
in the formula (7)
Figure FDA0002222753710000043
Is the coefficient of variation of external optical path with angle, L, in the sensing units0For the total initial geometric length of the actual path of the laser light propagating in the sensor unit, ns0Is the refractive index of the sensing unit material;
using compensated phase in combination with sensing cell material refractive index ns0Total initial geometric length L of the actual path of the laser light propagating in the sensor units0The coefficient of variation of the external optical path in the sensing unit along with the angle
Figure FDA0002222753710000051
And calculating to obtain the rotation angle of the rotary disc in the sensing unit.
CN201910940583.9A 2018-05-18 2018-05-18 External incident type angle sensing measuring device and method for bi-orthogonal plane mirror based on multi-longitudinal-mode self-mixing effect Expired - Fee Related CN110631512B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910940583.9A CN110631512B (en) 2018-05-18 2018-05-18 External incident type angle sensing measuring device and method for bi-orthogonal plane mirror based on multi-longitudinal-mode self-mixing effect

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201810481300.4A CN108680121B (en) 2018-05-18 2018-05-18 Incident type angle sensing measuring device and method in single-arbitrary-angle intersecting plane mirror
CN201910940583.9A CN110631512B (en) 2018-05-18 2018-05-18 External incident type angle sensing measuring device and method for bi-orthogonal plane mirror based on multi-longitudinal-mode self-mixing effect

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
CN201810481300.4A Division CN108680121B (en) 2018-05-18 2018-05-18 Incident type angle sensing measuring device and method in single-arbitrary-angle intersecting plane mirror

Publications (2)

Publication Number Publication Date
CN110631512A true CN110631512A (en) 2019-12-31
CN110631512B CN110631512B (en) 2021-08-06

Family

ID=63805703

Family Applications (5)

Application Number Title Priority Date Filing Date
CN201910940583.9A Expired - Fee Related CN110631512B (en) 2018-05-18 2018-05-18 External incident type angle sensing measuring device and method for bi-orthogonal plane mirror based on multi-longitudinal-mode self-mixing effect
CN201910940538.3A Active CN110631511B (en) 2018-05-18 2018-05-18 Right-angle prism type angle sensing measurement device and method based on multi-longitudinal-mode self-mixing effect
CN201910940599.XA Expired - Fee Related CN110631513B (en) 2018-05-18 2018-05-18 Incident type angle sensing measuring device and method in biorthogonal plane mirror
CN201910941460.7A Expired - Fee Related CN110631514B (en) 2018-05-18 2018-05-18 Pentagonal prism type angle sensing measurement device and method based on multi-longitudinal mode self-mixing effect
CN201810481300.4A Active CN108680121B (en) 2018-05-18 2018-05-18 Incident type angle sensing measuring device and method in single-arbitrary-angle intersecting plane mirror

Family Applications After (4)

Application Number Title Priority Date Filing Date
CN201910940538.3A Active CN110631511B (en) 2018-05-18 2018-05-18 Right-angle prism type angle sensing measurement device and method based on multi-longitudinal-mode self-mixing effect
CN201910940599.XA Expired - Fee Related CN110631513B (en) 2018-05-18 2018-05-18 Incident type angle sensing measuring device and method in biorthogonal plane mirror
CN201910941460.7A Expired - Fee Related CN110631514B (en) 2018-05-18 2018-05-18 Pentagonal prism type angle sensing measurement device and method based on multi-longitudinal mode self-mixing effect
CN201810481300.4A Active CN108680121B (en) 2018-05-18 2018-05-18 Incident type angle sensing measuring device and method in single-arbitrary-angle intersecting plane mirror

Country Status (1)

Country Link
CN (5) CN110631512B (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110411377B (en) * 2019-06-11 2021-09-28 湖北光安伦芯片有限公司 Right angle detection and adjustment system and method
CN111141744B (en) * 2019-12-31 2023-01-31 广州维思车用部件有限公司 Lens detection device
CN113340370B (en) * 2021-06-04 2023-01-24 淄博海源电子科技有限公司 Intelligent sensing Internet of things water meter based on heterogeneous network
CN114322825A (en) * 2021-12-08 2022-04-12 中国电子科技集团公司第十一研究所 Visual super-large-size optical plane detection device and method
CN118089597B (en) * 2024-04-24 2024-07-09 天津揽海慧听科技有限公司 Laser scanning angle measuring device and method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040207835A1 (en) * 2003-04-18 2004-10-21 Pioneer Fa Corporation & Pioneer Corporation Auto-collimator
CN101236076A (en) * 2008-02-29 2008-08-06 成都工具研究所 Laser angle interferometry system possessing standard angle rotating platform and its measurement method
CN101583462A (en) * 2006-11-08 2009-11-18 辛迪斯股份公司 Industrial machine provided with interferometric measuring means
CN107576285A (en) * 2017-10-12 2018-01-12 安徽大学 Laser mixes micro- angle measurement system and measuring method certainly

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4061724A (en) * 1975-09-22 1977-12-06 Union Carbide Corporation Crystalline silica
CN1073522A (en) * 1991-12-12 1993-06-23 清华大学 The laser longitudinal mode splitting angular transducer
DE4400680C2 (en) * 1994-01-12 1995-11-02 Kayser Threde Gmbh Device for determining changes in distance of an object
CN1090754C (en) * 1998-11-13 2002-09-11 清华大学 High-resolution surface plasma wave angle/refractive index sensor
US6885438B2 (en) * 2002-05-29 2005-04-26 Kent L. Deines System and method for measuring velocity using frequency modulation of laser output
CN1263999C (en) * 2002-08-21 2006-07-12 中国科学院长春光学精密机械与物理研究所 Cylindrical grating shaft interference encoder
CN1257382C (en) * 2003-09-19 2006-05-24 南开大学 Electrooptical angle measurer
CN101949685B (en) * 2010-09-08 2011-11-16 南京师范大学 Fiber laser self-mixing interferometer and measurement method thereof
CN102564909B (en) * 2011-11-29 2014-05-07 中国科学院安徽光学精密机械研究所 Laser self-mixing multi-physical parameter measurement method and device for atmospheric particulate
PL219676B1 (en) * 2012-01-27 2015-06-30 Politechnika Warszawska Measuring method for angular deviations of the laser beam and an interferometer for measuring the angular deviations of the laser beam
KR101364183B1 (en) * 2012-08-01 2014-02-20 한국과학기술원 Slope-angle sensor with accuracy in steady state and transient state
CN103472254B (en) * 2013-09-09 2016-03-23 中国科学院合肥物质科学研究院 Based on square wave current modulation and the laser of FP etalon light splitting from mixing velocity measuring system and method
KR101980950B1 (en) * 2013-12-27 2019-08-30 인텔 코포레이션 Asymmetric optical waveguide grating resonators & dbr lasers
TWI502170B (en) * 2014-01-22 2015-10-01 Academia Sinica Optical measurement system and method for measuring linear displacement, rotation and rolling angles
CN106802165A (en) * 2017-03-02 2017-06-06 阜阳师范学院 Speed and distance synchronous measuring method and device based on laser self-mixing interference

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040207835A1 (en) * 2003-04-18 2004-10-21 Pioneer Fa Corporation & Pioneer Corporation Auto-collimator
CN101583462A (en) * 2006-11-08 2009-11-18 辛迪斯股份公司 Industrial machine provided with interferometric measuring means
CN101236076A (en) * 2008-02-29 2008-08-06 成都工具研究所 Laser angle interferometry system possessing standard angle rotating platform and its measurement method
CN107576285A (en) * 2017-10-12 2018-01-12 安徽大学 Laser mixes micro- angle measurement system and measuring method certainly

Also Published As

Publication number Publication date
CN110631514B (en) 2021-03-30
CN108680121A (en) 2018-10-19
CN110631513A (en) 2019-12-31
CN110631512B (en) 2021-08-06
CN110631514A (en) 2019-12-31
CN108680121B (en) 2020-11-27
CN110631513B (en) 2021-03-30
CN110631511B (en) 2021-01-05
CN110631511A (en) 2019-12-31

Similar Documents

Publication Publication Date Title
CN110631512B (en) External incident type angle sensing measuring device and method for bi-orthogonal plane mirror based on multi-longitudinal-mode self-mixing effect
CA2007190C (en) Laser optical ultrasound detection
CN100434862C (en) Method for measuring minute angle based on self-commix interference of laser and apparatus thereof
CN110132179B (en) Biorthogonal internal incidence type laser self-mixing micro-angle measuring system and measuring method
CN101033937A (en) Method and device of light splitting, image-forming and synchronous phase-shifting in optical interferometry.
US3809481A (en) Single reflector interference spectrometer and drive system therefor
CN104713649B (en) A kind of Fourier transform spectrometer, interferometer
US5196902A (en) Two-beam interferometer apparatus and method, and spectrometer utilizing the same
CN105333815A (en) Super lateral resolution surface three-dimensional online interference measuring system based on spectral dispersion line scanning
CN110806397B (en) Liquid concentration sensing measurement device and method based on multi-longitudinal-mode self-mixing effect
US3782176A (en) Apparatus for measuring vibration in a moving object
CN105333816A (en) Super lateral resolution surface three-dimensional online interference measuring system based on spectral dispersion full field
CN101329200A (en) Two-way output double-corner reflection body interferometer
US3535024A (en) Interferometer servo system
EP2167908B1 (en) Improved interferometer
CN108709717B (en) Device and method for measuring resonant cavity FSR of multi-longitudinal-mode laser by using large-amplitude laser self-mixing vibration signal
JPS6134430A (en) Active mirror wave-front sensor
CN212780503U (en) Fourier near infrared spectrum interferometer and instrument for online material detection
CN114739509B (en) Quadrilateral common-path time modulation interference spectrum imaging device and method
Yan External dihedral-angle error measurement based on Differential Wavefront Sensing
JPH0648364Y2 (en) Laser frequency meter
CN118068347A (en) Multi-target absolute distance measurement light path system and method based on double-light comb interference
CN116295781A (en) Vibration and micro-angle synchronous measurement device and method based on multi-longitudinal-mode self-mixing effect
JPH01221602A (en) Two-beam interference type linear encoder
JPH04505215A (en) Symmetric carrier frequency interferometer

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20210806