阅读说明：本技术 基于漂移量反馈的高稳定性纳弧度量级角度测量方法与装置 (High-stability nanoradian magnitude angle measurement method and device based on drift amount feedback ) 是由 谭久彬 石剑 于洋 于 2021-07-30 设计创作，主要内容包括：本发明属于精密测量技术领域与光学工程领域,具体涉及基于漂移量反馈的高稳定性纳弧度量级角度测量方法与装置；该装置由LED光源、凸透镜、多狭缝光阑、分光镜、转折镜、偏转镜、准直物镜组、线阵CCD、四象限位置探测器以及平面反射镜组成；该方法使两路测量光束携带被测物角度变化信息,分别在两个传感器上形成各自图像,利用该两图像位置解算出被测物相对于光轴的俯仰角、偏航角,从而具有对被测物角度变化的探测能力；具有在相同测量量程下,角度极限分辨力达到纳弧度量级的技术优势；提高系统稳定性至十纳弧度量级,解决光束漂移量限制自准直仪极限分辨力的问题。此外,本发明所设计的系统装置具有结构体积小、测量精度高、测量频响高的技术优势。(The invention belongs to the technical field of precision measurement and the field of optical engineering, and particularly relates to a high-stability angle measurement method and device with a nanoradian magnitude based on drift feedback; the device consists of an LED light source, a convex lens, a multi-slit diaphragm, a spectroscope, a turning mirror, a deflection mirror, a collimation objective lens group, a linear array CCD, a four-quadrant position detector and a plane reflector; the method enables two measuring beams to carry the angle change information of the measured object, forms respective images on two sensors respectively, and utilizes the positions of the two images to calculate the pitch angle and the yaw angle of the measured object relative to an optical axis, thereby having the capability of detecting the angle change of the measured object; the method has the technical advantage that under the same measuring range, the angle limit resolution reaches the magnitude of nanoradian; the stability of the system is improved to ten-nanometer radian order, and the problem that the beam drift amount limits the ultimate resolution of the autocollimator is solved. In addition, the system device designed by the invention has the technical advantages of small structure volume, high measurement precision and high measurement frequency response.)

1. The high-stability nanoradian magnitude angle measuring device based on drift amount feedback is characterized by comprising a first spectroscope (2), a collimation objective group (4), a plane reflector (5), a first LED light source (6), a second convex lens (7), a first multi-slit diaphragm (8), a second LED light source (9), a third convex lens (10), a second multi-slit diaphragm (11), a second spectroscope (12), a first turning mirror (13), a second turning mirror (14), a third spectroscope (15), a first linear array CCD (16), a second linear array CCD (17), a fourth spectroscope (18) and a four-quadrant position detector (19); the collimation objective lens group (4) consists of a first convex lens (41) and a first concave lens (42); the light emitted by the first LED light source (6) and the second LED light source (9) is collimated by the second convex lens (7) and the third convex lens (10) respectively and then is incident to the first multi-slit diaphragm (8) and the second multi-slit diaphragm (11) in parallel; the first multi-slit diaphragm (8) and the second multi-slit diaphragm (11) are used as object planes, two beams of emitted light are converged by the first spectroscope (2), split by the fourth spectroscope (18) and divided into reflected light and transmitted light; the reflected light is vertically incident on a four-quadrant position photoelectric detector (19); the transmitted light is vertically incident to the collimating objective lens group (4) and collimated into parallel beams after being bent by the first bending mirror (13) and the second bending mirror (14); the parallel light beams are reflected by the plane reflector (5) and return along the original path, after being reflected by the second beam splitter (12), the parallel light beams are split by the third beam splitter (15), one path of the parallel light beams is incident on the first linear array CCD (16) for collecting imaging, and the other path of the parallel light beams is incident on the second linear array CCD (17) for collecting imaging;

the first multi-slit diaphragm (8) is a transmission diaphragm consisting of three parallel linear slits with equal distance and equal width, a first LED light source (6) is collimated by a second convex lens (7) and then irradiates the first multi-slit diaphragm (8), and a light beam emitted by the first multi-slit diaphragm is a first beam of measuring light of the device; the second multi-slit diaphragm (11) is the same as the first multi-slit diaphragm structure (8), but the slit direction of the second multi-slit diaphragm is vertical to the slit direction of the first multi-slit diaphragm (8), and the emitted light beam is the second beam measuring light of the device;

or

The first multi-slit diaphragm (8) is a transmission diaphragm consisting of four parallel linear slits with equal distance and equal width, a first LED light source (6) is collimated by a second convex lens (7) and then irradiates the first multi-slit diaphragm (8), and a light beam emitted by the first multi-slit diaphragm is a first beam of measuring light of the device; the second multi-slit diaphragm (11) is the same as the first multi-slit diaphragm structure (8), but the slit direction of the second multi-slit diaphragm is vertical to the slit direction of the first multi-slit diaphragm (8), and the emitted light beam is the second beam measuring light of the device;

the first linear array CCD (16) collects a first beam of measuring light for imaging, and the measuring direction of the sensor is mutually vertical to the slit direction of the first multi-slit diaphragm (8); a second linear array CCD (17) collects a second beam of measuring light for imaging, and the measuring direction of the sensor is mutually vertical to the slit direction of a second multi-slit diaphragm (11); the first linear array CCD (16) and the second linear array CCD (17) are arranged at the focal plane of the collimating objective lens group (4) and are conjugated with the positions of the first multi-slit diaphragm (8) and the second multi-slit diaphragm (11);

the four-quadrant position detector (19) is arranged behind the fourth light splitting mirror (18) and is used for collecting the real-time drift amount of the first beam of measuring light and the second beam of measuring light;

the first turning mirror (13) and the second turning mirror (14) are arranged in parallel, and the normal direction of the mirror surface and the incident direction of the light beam have a fixed small angle.

2. The high-stability nanoradian-level angle measurement device based on drift amount feedback of claim 1, further comprising a first deflection mirror (20) and a second deflection mirror (21);

the first deflection mirror (20) is arranged between the second convex lens (7) and the first multi-slit diaphragm (8), and the second deflection mirror (21) is arranged between the third convex lens (10) and the second multi-slit diaphragm (11) and is respectively used for finely adjusting the incidence directions of the first LED light source (6) and the second LED light source (9).

3. The high-stability nanoradian-level angle measurement device based on drift amount feedback is characterized by further comprising a first deflection mirror (20), a second deflection mirror (21), a second concave lens (43), a fourth convex lens (44) and a fifth convex lens (45);

the first deflection mirror (20) is arranged between the second convex lens (7) and the first multi-slit diaphragm (8), and the second deflection mirror (21) is arranged between the third convex lens (10) and the second multi-slit diaphragm (11) and is respectively used for finely adjusting the incidence directions of the first LED light source (6) and the second LED light source (9);

the second concave lens (43), the fourth convex lens (44), the fifth convex lens (45), the first convex lens (41) and the first concave lens (42) jointly form a collimation objective lens group (4).

4. The high-stability nanoradian-level angle measurement device based on drift amount feedback is characterized by further comprising a first deflection mirror (20), a second deflection mirror (21), a second concave lens (43), a fourth convex lens (44) and a fifth convex lens (45);

the first deflection mirror (20) is arranged between the second convex lens (7) and the first multi-slit diaphragm (8), and the second deflection mirror (21) is arranged between the third convex lens (10) and the second multi-slit diaphragm (11) and is respectively used for finely adjusting the incidence directions of the first LED light source (6) and the second LED light source (9);

the second concave lens (43), the fourth convex lens (44), the fifth convex lens (45), the first convex lens (41) and the first concave lens (42) jointly form a collimation objective lens group (4);

the fourth light splitting mirror (18) is arranged between the collimating objective lens group (4) and the plane reflecting mirror (5); two beams of measuring light emitted by the first multi-slit diaphragm (8) and the second multi-slit diaphragm (11) are split by the fourth light splitter (18), a reflected beam is reflected to the four-quadrant position detector (19) through the fourth light splitter (18) to be collected and imaged, and a transmitted beam is transmitted through the fourth light splitter (18) to continue to propagate.

5. The high-stability nanoradian magnitude angle measuring method based on drift amount feedback, which is realized on the high-stability nanoradian magnitude angle measuring device based on drift amount feedback in claim 1, is characterized by comprising the following steps of:

a, fixing a plane reflector (5) on the surface of a measured object;

step b, lighting the first LED light source (6) and the second LED light source (9), and adjusting the positions of the object to be measured and the plane reflector (5) to enable the geometric centers of the light spot images received by the first linear array CCD (16) and the second linear array CCD (17) to be positioned at the center positions of the two sensors;

c, adjusting the mounting directions of the first multi-slit diaphragm (8) and the second multi-slit diaphragm (11) to ensure that the directions of the light spot images received by the first linear array CCD (16) and the second linear array CCD (17) are respectively vertical to the mounting direction of the sensor;

d, controlling the first LED light source (6) and the second LED light source (9) to alternately flash at a fixed frequency, directly receiving two beams of measuring light emitted by the first LED light source (6) and the second LED light source (9) by the four-quadrant position detector (19), and alternately collecting the measuring light emitted by the first LED light source (6) and the second LED light source (9) by the first linear array CCD (16) and the second linear array CCD (17) respectively;

step e, when the plane reflector (5) rotates along with the measured object to generate a yaw angle and a pitch angle, the first linear array CCD (16) outputs a light beam and light spot displacement value generated by the first multi-slit diaphragm (8), wherein the light spot is at the position S1 away from the center of the image sensor, the second linear array CCD (17) outputs a light beam and light spot displacement value generated by the second multi-slit diaphragm (11), and the light spot is at the position S2 away from the center of the image sensor; the four-quadrant position detector (19) outputs the light spot displacement drift amounts E1 and E2 of the first LED light source (6) and the second LED light source (9);

step f, calculating alpha according to S1-E1 ═ f · tan (2 alpha) by using the displacement S1 of the light spot of the first linear array CCD (16) and the displacement drift amount E1 of the light spot of the four-quadrant position detector (19), wherein alpha is an angle of a yaw angle generated by a measured object; and calculating beta according to S2-E2 as f.tan (2 beta) by using the displacement S2 of the light spot of the second linear array CCD (17) and the displacement drift amount E2 of the light spot of the four-quadrant position detector (19), wherein the beta is the angle of the pitch angle generated by the measured object.

6. The high-stability angle measuring method based on drift amount feedback, which is implemented on the high-stability angle measuring device based on drift amount feedback of claim 2, claim 3 and claim 4, is characterized by comprising the following steps:

a, fixing a plane reflector (5) on the surface of a measured object;

step b, lighting the first LED light source (6) and the second LED light source (9), and adjusting the positions of the object to be measured and the plane reflector (5) to enable the geometric centers of the light spot images received by the first linear array CCD (16), the second linear array CCD (17) and the four-quadrant position detector (19) to be positioned at the center positions of the sensors;

c, adjusting the mounting directions of the first multi-slit diaphragm (8) and the second multi-slit diaphragm (11) to ensure that the directions of the light spot images received by the first linear array CCD (16) and the second linear array CCD (17) are respectively vertical to the mounting direction of the sensor;

d, controlling the first LED light source (6) and the second LED light source (9) to alternately flash at a fixed frequency, directly receiving two beams of measuring light emitted by the first LED light source (6) and the second LED light source (9) by the four-quadrant position detector (19), and alternately collecting the measuring light reflected by the first LED light source (6) and the second LED light source (9) respectively by the first linear array CCD (16) and the second linear array CCD (17);

step E, when the four-quadrant position detector (19) outputs the light spot displacement drift amounts E1 and E2 of the first LED light source (6) and the second LED light source (9), the first deflection mirror (20) generates angle change to adjust the light beam direction of the first LED light source (6), so that the light spot displacement drift amount E1 is always 0, and the second deflection mirror (21) generates angle change to adjust the light beam direction of the second LED light source (9), so that the light spot displacement drift amount E2 is always 0;

step f, when the plane reflector (5) rotates along with the measured object to generate a yaw angle and a pitch angle, the first linear array CCD (16) outputs a light beam and light spot displacement value generated by the first multi-slit diaphragm (8), wherein the light spot is at the position S1 away from the center of the image sensor, the second linear array CCD (17) outputs a light beam and light spot displacement value generated by the second multi-slit diaphragm (11), and the light spot is at the position S2 away from the center of the image sensor;

step g, calculating alpha according to S1 ═ f · tan (2 alpha) by using a displacement S1 of the light spot of the first linear array CCD (16), wherein alpha is an angle at which a yaw angle is generated by the measured object; and calculating beta according to S2 ═ f · tan (2 beta) by using the displacement S2 of the light spot of the second linear CCD (17), wherein beta is the angle of the measured object generating the pitch angle.

Technical Field

The invention belongs to the technical field of precision measurement, and particularly relates to a high-stability angle measuring method and device with a nanoradian magnitude based on drift amount feedback.

Background

In the field of precision measurement technology, optical engineering, advanced scientific experiments and high-end precision equipment manufacturing, there is an urgent need for a technique for measuring an auto-collimation angle with high resolution, high precision and high stability in a large working range. It supports the development of technical and instrumental equipment in the above mentioned fields.

In the field of precision measurement technology and instruments, the autocollimator is combined with the circular grating, and can perform any line angle measurement; the autocollimation technology is combined with the polyhedral prism, so that the surface angle measurement and the roundness measurement can be performed; the maximum working distance is from several meters to hundreds of meters; the resolution was from 0.1 to 0.01 arcsec.

In the fields of optical engineering and advanced scientific experiments, an autocollimator is combined with two-dimensional mutually perpendicular circular gratings, so that the spatial angle can be measured; the position reference is formed by two paths of autocollimators, and the included angle or the parallelism of every two optical axes can be measured. The angular operation ranges from tens of arcseconds to tens of angular minutes.

In the field of manufacturing of advanced scientific experimental devices and high-end precision equipment, the autocollimator can be used for measuring the angular rotation precision of the advanced scientific experimental device and the high-end precision equipment on the basis of rotary motion, and measuring the spatial linear precision of a linear motion reference and the parallelism and perpendicularity of every two motion references.

The auto-collimation technology has the advantages of non-contact, high measurement precision, convenience in use and the like, and is widely applied to the fields.

As shown in fig. 1, the conventional autocollimator includes a laser light source 1, a first convex lens 41, a first beam splitter 2, and an image sensor 3; the light beam emitted by the laser light source 1 is collimated into a parallel light beam by the convex lens 41 and then enters the reflecting surface of the measured object 5; the light beam reflected from the reflecting surface of the measured object 5 is imaged by the image sensor 3. In this configuration, the focal length of the collimating lens of the autocollimator is typically 500mm, the limiting displacement resolution of the conventional sensor is 30 to 50nm, and the effective measuring area is typically 5 × 5mm²(ii) a Meanwhile, the laser light source has larger drift amount, so that the measurement instability seriously influences the measurement ultimate resolution. The conditions are limited, so that the device can measure the spatial angle information of the measured objectIt is difficult to break through the resolution bottleneck of 0.003 arc-seconds (on the order of ten nanoradians) in the 300 arc-second range.

In summary, the system has the following two problems:

firstly, because the limit angle resolution of the autocollimator and the measuring range have a contradiction relationship, the high angle resolution of the nano radian order cannot be achieved in the traditional measuring range. If the focal length of the collimating objective lens of the autocollimator is increased, the resolution of the limiting angle of the autocollimator is improved, but the measuring range is reduced in proportion; if the effective measurement area of the sensor is increased, the ultimate displacement resolution is reduced, and the ultimate angle resolution of the autocollimator is also reduced. Therefore, the traditional technology can hardly reach the high angular resolution of 0.001 arc second (nano radian order) in the range of 300 arc second;

second, the laser source of the conventional auto-collimation technology has a beam drift amount, and the angular drift amount and the horizontal drift amount of the beam seriously affect the stability of the auto-collimator, thereby limiting the limit resolution of the auto-collimator. After the laser light source is collimated by the convex lens, the collimation precision can only reach 10 due to the drift amount of the laser light source^-7Radian order (hundredth radian order). The noise caused by the instability of the light source seriously limits the improvement of the limit resolution of the autocollimator.

Therefore, the traditional auto-collimation technology cannot achieve high angular resolution of a nanoradian order in the traditional measurement range while not having high measurement stability.

Disclosure of Invention

The invention discloses a high-stability angle measuring method and device based on drift amount feedback, aiming at the problems that the traditional auto-collimation angle measuring device cannot achieve high angle resolution of a nanoradian order in the traditional measuring range and does not have high measuring stability.

The method uses a four-quadrant position detector as a feedback detection module at the light source emergent end to detect the drift amounts of the horizontal drift and the angular drift generated by a light source in the device in real time and high precision; the deflection mirror is used as a feedback execution module, closed-loop feedback control is carried out in real time according to the measured drift amount, and light spots emitted by the light source are always controlled at the central position of the four-quadrant position detector, so that the stability of the light source is directly improved, and the drift amount is reduced. Experiments show that the method controls the flat drift and the angle drift of the light source to be ten-nanometer radian magnitude in real time, and solves the problem that the drift of the light beam limits the ultimate resolution of the autocollimator;

meanwhile, the method utilizes a collimating objective lens group, a multi-slit diaphragm, a two-way spectroscope and a two-way linear array CCD to realize a shunt multiplexing technology, and realizes the angle resolution measurement of the magnitude of nanoradian in a large range. Experiments show that the method can realize the angular resolution of one thousandth of an arc second within the range of three hundred arc seconds, and solve the problem that the autocollimator cannot achieve the high angular resolution of a nanoradian order within the traditional measurement range;

therefore, compared with the traditional auto-collimation measuring device, the auto-collimation measuring device has the technical advantages of high angle resolution and high measuring stability in the order of nano radian under the condition of the same measuring range.

The purpose of the invention is realized as follows:

the high-stability nanoradian magnitude angle measuring device based on drift amount feedback comprises a first LED light source, a second LED light source, a first convex lens, a fourth convex lens, a fifth convex lens, a first concave lens, a first multi-slit diaphragm, a second multi-slit diaphragm, a first spectroscope, a second spectroscope, a third spectroscope, a fourth spectroscope, a first turning mirror, a second turning mirror, a first linear array CCD, a second linear array CCD, a four-quadrant position detector and a plane mirror; the first LED light source and the second LED light source are collimated by the fourth convex lens and the fifth convex lens respectively and then are incident to the first multi-slit diaphragm and the second multi-slit diaphragm in parallel; the first multi-slit diaphragm and the second multi-slit diaphragm are used as object surfaces, two beams of emitted light are converged by the first spectroscope and split by the fourth spectroscope into reflected light and transmitted light; the reflected light vertically enters a four-quadrant position photoelectric detector; after transmitted light is bent by the first bending mirror and the second bending mirror, the transmitted light vertically enters the collimating objective group to be collimated into parallel light beams, then returns along the original path after being reflected by the plane reflector, is split by the third beam splitter after being reflected by the second beam splitter, one path of the transmitted light enters the first linear array CCD for collecting and imaging, and the other path of the transmitted light enters the second linear array CCD for collecting and imaging;

the first multi-slit diaphragm is a transmission diaphragm consisting of three parallel equidistant equal-width linear slits, and a first LED light source is collimated by a second convex lens and then irradiates the first multi-slit diaphragm, so that three parallel equidistant equal-width linear light spots are an object of the device, and a light beam emitted by the three parallel equidistant equal-width linear light spots is a first beam of measuring light of the device; the second multi-slit diaphragm has the same structure as the first multi-slit diaphragm, but the slit direction of the second multi-slit diaphragm is vertical to that of the first multi-slit diaphragm, so that an object emitting the second beam of measuring light is also three parallel linear light spots with equal distance and equal width, and is vertical to the light spots of the first beam of measuring light;

or

The first multi-slit diaphragm is a transmission diaphragm consisting of four parallel equidistant equal-width linear slits, and a first LED light source is collimated by a second convex lens and then irradiates the first multi-slit diaphragm, so that four parallel equidistant equal-width linear light spots are an object of the device, and a light beam emitted by the four parallel equidistant equal-width linear light spots is a first beam of measuring light of the device; the second multi-slit diaphragm has the same structure as the first multi-slit diaphragm, but the slits of the second multi-slit diaphragm are perpendicular to the slits of the first multi-slit diaphragm, so that the object emitting the second beam of measuring light is also four parallel linear light spots with equal distance and equal width, and is perpendicular to the light spots of the first beam of measuring light;

the first linear array CCD acquires a first beam of measuring light for imaging, and the measuring direction of the sensor is mutually vertical to the slit direction of the first multi-slit diaphragm; a second linear array CCD acquires a second beam of measuring light for imaging, and the measuring direction of the sensor is mutually vertical to the slit direction of a second multi-slit diaphragm;

the four-quadrant position detector collects the real-time drift amount of the first beam of measuring light and the second beam of measuring light, corrects the measuring result and further improves the stability of the system device;

the collimating objective group consists of a first convex lens and a first concave lens to form a telephoto objective group, and the focal length of the telephoto objective group is far greater than that of the first convex lens, so that the limiting angle resolution of the autocollimator is improved;

the first turning mirror and the second turning mirror are arranged in parallel and have a fixed small angle with the main optical axis, so that the long-focus optical path of the system device can be folded, and the space size of the system is reduced.

A high-stability nanoradian magnitude angle measuring method based on drift amount feedback, which is realized on the high-stability nanoradian magnitude angle measuring device based on drift amount feedback, comprises the following steps:

a, fixing a plane reflector to the surface of a measured object;

b, lighting the first LED light source and the second LED light source, and adjusting the positions of the object to be measured and the plane reflector to enable the geometric centers of the light spot images received by the first linear array CCD, the second linear array CCD and the four-quadrant position detector to be positioned at the center position of each sensor;

c, adjusting the mounting directions of the first multi-slit diaphragm and the second multi-slit diaphragm to ensure that the directions of the light spot images received by the first linear array CCD and the second linear array CCD are respectively vertical to the mounting direction of the sensor;

d, controlling the first LED light source and the second LED light source to alternately flash at a fixed frequency, wherein the four-quadrant position detector directly receives two beams of measuring light emitted by the first LED light source and the second LED light source, and the first linear array CCD and the second linear array CCD alternately collect the measuring light emitted by the first LED light source and the second LED light source respectively;

step e, when the plane reflector rotates along with the measured object to generate a yaw angle and a pitch angle, the first linear array CCD outputs a light beam and light spot displacement value generated by the first multi-slit diaphragm, wherein the distance between the light spot and the center of the image sensor is S1, the second linear array CCD outputs a light beam and light spot displacement value generated by the second multi-slit diaphragm, and the distance between the light spot and the center of the image sensor is S2; the four-quadrant position detector outputs spot displacement drift amounts E1 and E2 of the first LED light source and the second LED light source;

step f, calculating alpha according to S1-E1 ═ f · tan (2 alpha) by using the displacement S1 of the first linear array CCD light spot and the displacement drift amount E1 of the four-quadrant position detector light spot, wherein alpha is an angle of a yaw angle generated by a measured object; and calculating beta according to S2-E2 as f · tan (2 beta) by using the displacement S2 of the second linear array CCD light spot and the displacement drift amount E2 of the four-quadrant position detector light spot, wherein the beta is an angle of the measured object generating a pitch angle.

Has the advantages that:

1. aiming at the problem that the traditional auto-collimation angle measuring device does not have high measurement stability, a high-stability nanoradian magnitude angle measuring method based on drift amount feedback is provided. The method uses a four-quadrant position detector as a feedback detection module at the light source emergent end to detect the drift amounts of the horizontal drift and the angular drift generated by a light source in the device in real time and high precision; the deflection mirror is used as a feedback execution module, closed-loop feedback control is carried out in real time according to the measured drift amount, and light spots emitted by the light source are always controlled at the central position of the four-quadrant position detector, so that the stability of the light source is directly improved, and the drift amount is reduced; finally, the flat drift and the angle drift of the light source are controlled to be ten-nanometer radian magnitude, and the problem that the limit resolution of the autocollimator is limited due to the drift of the light beam is solved, which is one of the innovation points of the invention different from the prior art;

2. compared with the traditional measuring device, the device provided by the invention has the advantages that the laser light source is replaced by the LED light source, so that the measurement instability caused by the drift amount of the light source is directly reduced; the second convex lens and the third convex lens are used for collimating light emitted by the LED light source, the first multi-slit diaphragm and the second multi-slit diaphragm are used for modulating two paths of parallel light, and the first multi-slit diaphragm and the second multi-slit diaphragm are used as objects of the system device, so that the influence of angle drift and flat drift is further reduced, and the system device is different from the second innovation point of the prior art;

3. aiming at the problem that the traditional auto-collimation angle measuring device cannot achieve high angle resolution of a nanoradian order in the traditional measuring range, the method utilizes a collimation objective lens group, a multi-slit diaphragm, a double-path spectroscope and a double-path linear array CCD to realize a shunt multiplexing technology, and achieves the angle resolution measurement of the nanoradian order in a large range. The method can realize the angular resolution of one thousandth of angular second within the range of three hundred angular seconds, finally realize that the system reaches the high angular resolution of the magnitude of nanoradian within the traditional measuring range, break through the contradiction relation between the ultimate angular resolution of the autocollimator and the measuring range, and is the innovation point of the invention which is different from the prior art.

In addition, the invention has the following technical advantages:

firstly, a first turning mirror and a second turning mirror are selected to fold a long-focus light path of the system for two times, so that the volume of the system device is reduced, the system device is more suitable for a field measurement environment, and the influence of air fluctuation on a measurement result caused by overlarge size of the system device is avoided;

secondly, selecting a first multi-slit diaphragm and a second multi-slit diaphragm as objects of the angle measuring device, and simultaneously positioning three stripe light spots on each linear array CCD to improve the measuring stability of the system and the measuring precision of the angle measuring device;

thirdly, two paths of one-dimensional linear array CCDs are used for replacing two-dimensional image sensors, the total number of pixels of each sensor is small, the requirement on subsequent image processing technology is lowered, and the frequency response of the measuring device is improved.

Drawings

Fig. 1 is a schematic structural view of a conventional self-collimation angle measuring apparatus.

FIG. 2 is a schematic structural diagram of a first embodiment of a high-stability nanoradian-level angle measurement device based on drift amount feedback.

Fig. 3 is a schematic view of the structure and installation direction of the first multi-slit diaphragms 8 and 11 according to the first embodiment.

Fig. 4 is a schematic view of the structure and the installation direction of the second multi-slit diaphragms 8 and 11 according to the first embodiment.

Fig. 5 is a schematic view of the structure and mounting direction of the linear CCDs 16 and 17 according to an embodiment.

FIG. 6 is a schematic structural diagram of a second embodiment of the high-stability angle measuring apparatus with nanoradian measure based on drift amount feedback.

Fig. 7 is a schematic structural diagram of a third embodiment of the high-stability nanoradian-level angle measurement device based on drift amount feedback.

Fig. 8 is a schematic structural diagram of a fourth embodiment of the high-stability angle measuring apparatus with a nanoradian measure based on drift amount feedback.

In the figure: 1 laser light source, 2 first spectroscope, 3 image sensor, 4 collimation objective lens group, 41 first convex lens, 42 first concave lens, 43 second concave lens, 44 fourth convex lens, 45 fifth convex lens, 5 plane reflector, 6 first LED light source, 7 second convex lens, 8 first multi-slit diaphragm, 9 second LED light source, 10 third convex lens, 11 second multi-slit diaphragm, 12 second spectroscope, 13 first turning mirror, 14 second turning mirror, 15 third spectroscope, 16 first linear array CCD, 17 second linear array CCD, 18 fourth spectroscope, 19 four quadrant position detector, 20 first turning mirror, 21 second turning mirror.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The following describes in further detail specific embodiments of the present invention with reference to the accompanying drawings.

Detailed description of the preferred embodiment

The embodiment is an embodiment of a high-stability angle measuring device with a nanoradian magnitude based on drift amount feedback.

The high-stability angle measuring device with the magnitude of nanoradian based on drift feedback in the embodiment has a schematic structural diagram as shown in fig. 2. The angle measuring device comprises a first spectroscope 2, a collimation objective lens group 4 (a first convex lens 41 and a first concave lens 42), a plane reflector 5, a first LED light source 6, a second convex lens 7, a first multi-slit diaphragm 8, a second LED light source 9, a third convex lens 10, a second multi-slit diaphragm 11, a second spectroscope 12, a first turning mirror 13, a second turning mirror 14, a third spectroscope 15, a first linear array CCD16, a second linear array CCD17, a fourth spectroscope 18 and a four-quadrant position detector 19.

The first LED light source 6 and the second LED light source 9 are collimated by the second convex lens 7 and the third convex lens 10 respectively and then are incident in parallel to the first multi-slit diaphragm 8 and the second multi-slit diaphragm 11; with the first multi-slit diaphragm 8 and the second multi-slit diaphragm 11 as object planes, two beams of emitted light are converged by the first beam splitter 2, split by the fourth beam splitter 18 and divided into reflected light and transmitted light; the reflected light is vertically incident on the four-quadrant position photodetector 19; the transmitted light is vertically incident to the collimating objective lens group 4 and collimated into parallel beams after being bent by the first bending mirror 13 and the second bending mirror 14; the light beam is reflected by the plane mirror and returns along the original path, and is reflected by the second beam splitter 12 and split by the third beam splitter 15, wherein one path of light is incident on the first linear array CCD16 for collection and imaging, and the other path of light is incident on the second linear array CCD17 for collection and imaging;

the first multi-slit diaphragm 8 is a transmissive diaphragm consisting of three parallel equidistant equal-width linear slits, and the first LED light source 6 is collimated by the second convex lens 7 and then irradiates the first multi-slit diaphragm 8, so that three parallel equidistant equal-width linear light spots are an object of the device, and a light beam emitted by the three parallel equidistant equal-width linear light spots is a first beam of measuring light of the device; the second multi-slit diaphragm 11 is the same as the first multi-slit diaphragm structure 8, but the slit direction of the second multi-slit diaphragm is perpendicular to the slit direction of the first multi-slit diaphragm 8, so that the object emitting the second beam of measuring light is also three parallel linear light spots with equal distance and equal width, and is perpendicular to the light spots of the first beam of measuring light;

or

The first multi-slit diaphragm 8 is a transmissive diaphragm consisting of four parallel equidistant equal-width linear slits, and the first LED light source 6 is collimated by the second convex lens 7 and then irradiates the first multi-slit diaphragm 8, so that four parallel equidistant equal-width linear light spots are an object of the device, and light beams emitted by the four parallel equidistant equal-width linear light spots are a first beam of measuring light of the device; the second multi-slit diaphragm 11 is the same as the first multi-slit diaphragm structure 8, but the slit direction of the second multi-slit diaphragm is perpendicular to the slit direction of the first multi-slit diaphragm 8, so that the object emitting the second beam of measuring light is also four parallel linear light spots with equal distance and equal width, and is perpendicular to the light spots of the first beam of measuring light;

the first linear array CCD16 collects a first beam of measuring light for imaging, and the measuring direction of the sensor is mutually vertical to the slit direction of the first multi-slit diaphragm 8; the second linear array CCD17 collects the second beam of measuring light for imaging, and the measuring direction of the sensor is mutually vertical to the slit direction of the second multi-slit diaphragm 11;

the four-quadrant position detector 19 is arranged behind the fourth beam splitter 18 and is used for collecting the real-time drift amount of the first beam of measuring light and the second beam of measuring light;

the collimating objective lens group 4 consists of a first convex lens 41 and a first concave lens 42; the first linear array CCD16 and the second linear array CCD17 are arranged at the focal plane of the collimating objective lens group 4 and are conjugated with the positions of the first multi-slit diaphragm 8 and the second multi-slit diaphragm 11; when the plane mirror 5 is perpendicular to the optical axis and does not generate angle change, the centers of light spots collected by the first linear array CCD16 and the second linear array CCD17 are both at the geometric center position of the sensor;

the first turning mirror 13 and the second turning mirror 14 are arranged in parallel with each other and have a fixed small angle with the main optical axis.

The measurement principle is as follows:

when the object to be measured generates angular changes of the yaw angle α and the pitch angle β, the plane mirror 5 also generates angular changes of the yaw angle α and the pitch angle β. The two measuring beams incident on the plane mirror 5 generate deflection angles of 2 a and 2 β with the light beam reflected by the plane mirror 5 because the plane mirror 5 rotates with the object to be measured to generate yaw and pitch angles.

Controlling the first LED light source 6 and the second LED light source 9 to alternately flash at a fixed frequency, and at the moment, alternately collecting the measuring light emitted by the first LED light source 6 and the second LED light source 9 by the first linear array CCD16 and the second linear array CCD17 respectively; the principle of measurement of the traditional autocollimator is consistent, two measuring beams are respectively converged on a first linear array CCD16 and a second linear array CCD17, and the central positions of a beam spot and a linear array CCD sensor respectively generate displacements S1 and S2.

The four-quadrant position detector 19 measures the drift amounts of the first LED light source 6 and the second LED light source 9 in real time, and the light beam spot and the center position of the four-quadrant position detector 19 generate displacement drift amounts E1 and E2, respectively.

And satisfies the following relationships, S1-E1 ═ f · tan (2 α), S2-E2 ═ f · tan (2 β), and f is the focal length of the quasi-straight objective lens group 4.

Therefore, the angular changes of the yaw angle a and the pitch angle β of the object to be measured can be calculated according to the displacements S1 and S2 of the light spots on the first linear array CCD16 and the second linear array CCD17 and the sensor center positions, and the displacement drifts E1 and E2 of the light spots on the four-quadrant position detector 19 and the sensor center positions.

The embodiment of the method for measuring the angle of the high-stability nanoradian order based on the drift amount feedback comprises the following steps of:

step a, fixing a plane reflector 5 on the surface of a measured object;

step b, lighting the first LED light source 6 and the second LED light source 9, and adjusting the positions of the object to be measured and the plane reflector 5 to enable the geometric centers of the light spot images received by the first linear array CCD16 and the second linear array CCD17 to be positioned at the center positions of the two sensors;

c, adjusting the mounting directions of the first multi-slit diaphragm 8 and the second multi-slit diaphragm 11, so that the directions of the light spot images received by the first linear array CCD16 and the second linear array CCD17 are respectively perpendicular to the mounting directions of the sensors;

step d, controlling the first LED light source 6 and the second LED light source 9 to alternately flash at a fixed frequency, wherein the four-quadrant position detector 19 directly receives two beams of measuring light emitted by the first LED light source 6 and the second LED light source 9, and the first linear array CCD16 and the second linear array CCD17 alternately collect the measuring light emitted by the first LED light source 6 and the second LED light source 9 respectively;

step e, when the plane mirror 5 rotates along with the measured object to generate a yaw angle and a pitch angle, the first linear array CCD16 outputs a light beam and light spot displacement value generated by the first multi-slit diaphragm 8, wherein the light spot is S1 away from the center of the image sensor, and the second linear array CCD17 outputs a light beam and light spot displacement value generated by the second multi-slit diaphragm 11, wherein the light spot is S2 away from the center of the image sensor; the four-quadrant position detector 19 outputs spot displacement drift amounts E1 and E2 of the first LED light source 6 and the second LED light source 9;

step f, calculating alpha according to S1-E1 ═ f · tan (2 alpha) by using the displacement S1 of the light spot of the first linear array CCD16 and the displacement drift amount E1 of the light spot of the four-quadrant position detector 19, wherein alpha is an angle of a yaw angle generated by the measured object; and calculating beta according to S2-E2 ═ f · tan (2 beta) by using the displacement S2 of the light spot of the second linear array CCD17 and the displacement drift amount E2 of the light spot of the four-quadrant position detector 19, wherein the beta is an angle of the measured object generating the pitch angle.

The innovation point of the invention is that the first LED light source 6 and the second LED light source 9 are used as the light sources of the system device, so that the measurement instability caused by the drift amount of the light sources is directly reduced; the second convex lens 7 and the third convex lens 10 are used for collimating light emitted by the LED light source, the first multi-slit diaphragm 8 and the second multi-slit diaphragm 11 are used for modulating two paths of parallel light, and the first multi-slit diaphragm 8 and the second multi-slit diaphragm 11 are used as objects of the system device, so that the influence of angle drift and flat drift is further reduced; meanwhile, a four-quadrant position detector 19 is used as a feedback detection module to detect the drift amounts of the flat drift and the angle drift generated by a light source in the device in real time and high precision; the first deflection mirror 20 and the second deflection mirror 21 are used as feedback execution modules to perform closed-loop feedback control in real time according to the measured drift amount, and the light spot emitted by the light source is always controlled at the central position of the four-quadrant position detector 19; therefore, the horizontal drift and the angular drift of the light source are controlled to be in ten-nanometer radian magnitude in real time, and the problem that the limit resolution of the autocollimator is limited due to the drift of the light beam is solved;

the present invention uses the first convex lens 41 and the first concave lens 42 to form the collimating objective lens group 4, and uses the first linear array CCD16 and the second linear array CCD17 as the sensors of the system device. In the structure, the collimating objective group enlarges the focal length of the collimating objective of the angle measuring device to 3-4 times, thereby improving the limit angle resolution of the whole system to the magnitude of nano radian; the two one-dimensional linear array CCD sensors improve the measuring range by 3-4 times without reducing the ultimate displacement resolution of the sensor end, thereby solving the problem of reducing the measuring range caused by enlarging the focal length. Finally, the system achieves high angle resolution of a nano radian order in the traditional measurement range, and the contradiction relation between the ultimate angle resolution and the measurement range of the autocollimator is broken through.

Therefore, compared with the traditional self-collimation angle measuring device, the invention has the technical advantages that under the same measuring range, the angle limit resolution reaches the magnitude of nano radian and the measuring stability is high.

Detailed description of the invention

The embodiment is an embodiment of a high-stability angle measuring device with a nanoradian magnitude based on drift amount feedback.

The schematic structural diagram of the high-stability angle measuring device with the nanoradian magnitude based on the drift amount feedback in this embodiment is shown in fig. 6. On the basis of the first embodiment, in this embodiment, a first deflection mirror 20 is added between the second convex lens 7 and the first multi-slit aperture stop 8, and a second deflection mirror 21 is added between the third convex lens 10 and the second multi-slit aperture stop 11, as a feedback execution module, as shown in fig. 6.

The embodiment of the method for measuring the angle of the high-stability nanoradian order based on the drift amount feedback comprises the following steps of:

step a, fixing a plane reflector 5 on the surface of a measured object;

step b, lighting the first LED light source 6 and the second LED light source 9, and adjusting the positions of the object to be measured and the plane reflector 5 to enable the geometric centers of the light spot images received by the first linear array CCD16, the second linear array CCD17 and the four-quadrant position detector 19 to be positioned at the center position of each sensor;

c, adjusting the mounting directions of the first multi-slit diaphragm 8 and the second multi-slit diaphragm 11, so that the directions of the light spot images received by the first linear array CCD16 and the second linear array CCD17 are respectively perpendicular to the mounting directions of the sensors;

step d, controlling the first LED light source 6 and the second LED light source 9 to alternately flash at a fixed frequency, wherein the four-quadrant position detector 19 directly receives two beams of measuring light emitted by the first LED light source 6 and the second LED light source 9, and the first linear array CCD16 and the second linear array CCD17 alternately collect the measuring light reflected back after being emitted by the first LED light source 6 and the second LED light source 9 respectively;

step E, when the four-quadrant position detector 19 outputs the light spot displacement drift amounts E1 and E2 of the first LED light source 6 and the second LED light source 9, the first deflection mirror 20 generates an angle change to adjust the light beam direction of the first LED light source 6, so that the light spot displacement drift amount E1 is always 0, and the second deflection mirror 21 generates an angle change to adjust the light beam direction of the second LED light source 9, so that the light spot displacement drift amount E2 is always 0;

step f, when the plane mirror 5 rotates along with the measured object to generate a yaw angle and a pitch angle, the first linear array CCD16 outputs a light beam and light spot displacement value generated by the first multi-slit diaphragm 8, wherein the light spot is S1 away from the center of the image sensor, and the second linear array CCD17 outputs a light beam and light spot displacement value generated by the second multi-slit diaphragm 11, wherein the light spot is S2 away from the center of the image sensor;

step g, calculating alpha according to the displacement S1 of the light spot of the first linear array CCD16 and S1 ═ f · tan (2 alpha), wherein alpha is an angle of a yaw angle generated by a measured object; the displacement S2 of the light spot of the second linear array CCD17 is used to calculate β according to S2 ═ f · tan (2 β), where β is the angle at which the measured object generates the pitch angle.

The innovation point of the invention is that the fourth light splitting mirror 18 and the four-quadrant position detector 19 are used as feedback detection modules, the first deflection mirror 20 and the second deflection mirror 21 are added as feedback execution modules, and the light source drift amount is compensated in real time by measuring the drift amounts of light beams of two LED light sources in real time and controlling the deflection mirrors in a closed loop mode, thereby solving the problem of measurement instability caused by the light source drift amount.

Detailed description of the preferred embodiment

The embodiment is an embodiment of a high-stability angle measuring device with a nanoradian magnitude based on drift amount feedback.

The structural schematic diagram of the high-stability angle measuring device with the magnitude of nanoradians based on the drift amount feedback in this embodiment is shown in fig. 7. On the basis of the first specific embodiment, in this embodiment, a first deflecting mirror 20 is added between the second convex lens 7 and the first multi-slit diaphragm 8, and a second deflecting mirror 21 is added between the third convex lens 10 and the second multi-slit diaphragm 11, and is used as a feedback execution module; in the collimating objective lens group 4, a second concave lens 43, a fourth convex lens 44 and a fifth convex lens 45 are added, as shown in fig. 7.

The embodiment of the method for measuring the angle of the high-stability nanoradian order based on the drift amount feedback comprises the following steps of:

step a, fixing a plane reflector 5 on the surface of a measured object;

step b, lighting the first LED light source 6 and the second LED light source 9, and adjusting the positions of the object to be measured and the plane reflector 5 to enable the geometric centers of the light spot images received by the first linear array CCD16, the second linear array CCD17 and the four-quadrant position detector 19 to be positioned at the center position of each sensor;

c, adjusting the mounting directions of the first multi-slit diaphragm 8 and the second multi-slit diaphragm 11, so that the directions of the light spot images received by the first linear array CCD16 and the second linear array CCD17 are respectively perpendicular to the mounting directions of the sensors;

step d, controlling the first LED light source 6 and the second LED light source 9 to alternately flash at a fixed frequency, wherein the four-quadrant position detector 19 directly receives two beams of measuring light emitted by the first LED light source 6 and the second LED light source 9, and the first linear array CCD16 and the second linear array CCD17 alternately collect the measuring light reflected back after being emitted by the first LED light source 6 and the second LED light source 9 respectively;

step E, when the four-quadrant position detector 19 outputs the light spot displacement drift amounts E1 and E2 of the first LED light source 6 and the second LED light source 9, the first deflection mirror 20 generates an angle change to adjust the light beam direction of the first LED light source 6, so that the light spot displacement drift amount E1 is always 0, and the second deflection mirror 21 generates an angle change to adjust the light beam direction of the second LED light source 9, so that the light spot displacement drift amount E2 is always 0;

step f, when the plane mirror 5 rotates along with the measured object to generate a yaw angle and a pitch angle, the first linear array CCD16 outputs a light beam and light spot displacement value generated by the first multi-slit diaphragm 8, wherein the light spot is S1 away from the center of the image sensor, and the second linear array CCD17 outputs a light beam and light spot displacement value generated by the second multi-slit diaphragm 11, wherein the light spot is S2 away from the center of the image sensor;

step g, calculating alpha according to the displacement S1 of the light spot of the first linear array CCD16 and S1 ═ f · tan (2 alpha), wherein alpha is an angle of a yaw angle generated by a measured object; the displacement S2 of the light spot of the second linear array CCD17 is used to calculate β according to S2 ═ f · tan (2 β), where β is the angle at which the measured object generates the pitch angle.

The innovation point of the present invention is that a second concave lens 43, a fourth convex lens 44 and a fifth convex lens 45 are added to the collimating objective lens group 4 to form a new collimating objective lens group 4. The new collimating objective group has more optimized parameters, the influence of the aberration of the optical system of the device on the measurement result can be reduced, and the system error of the whole device is reduced.

Detailed description of the invention

The embodiment is an embodiment of a high-stability angle measuring device with a nanoradian magnitude based on drift amount feedback.

The structural schematic diagram of the high-stability angle measuring device with the magnitude of nanoradians based on the drift amount feedback in this embodiment is shown in fig. 8. On the basis of the first embodiment, in this embodiment, a fourth light splitting mirror 18 and a four-quadrant position detector 19 are added between the collimating objective lens group 4 and the plane reflecting mirror 5 as a feedback detection module; a first deflection mirror 20 is added between the second convex lens 7 and the first multi-slit diaphragm 8, and a second deflection mirror 21 is added between the third convex lens 10 and the second multi-slit diaphragm 11 as a feedback execution module; in the collimating objective lens group 4, a second concave lens 43, a fourth convex lens 44 and a fifth convex lens 45 are added, as shown in fig. 8.

The embodiment of the method for measuring the angle of the high-stability nanoradian order based on the drift amount feedback comprises the following steps of:

step a, fixing a plane reflector 5 on the surface of a measured object;

step b, lighting the first LED light source 6 and the second LED light source 9, and adjusting the positions of the object to be measured and the plane reflector 5 to enable the geometric centers of the light spot images received by the first linear array CCD16, the second linear array CCD17 and the four-quadrant position detector 19 to be positioned at the center position of each sensor;

c, adjusting the mounting directions of the first multi-slit diaphragm 8 and the second multi-slit diaphragm 11, so that the directions of the light spot images received by the first linear array CCD16 and the second linear array CCD17 are respectively perpendicular to the mounting directions of the sensors;

step d, controlling the first LED light source 6 and the second LED light source 9 to alternately flash at a fixed frequency, wherein the four-quadrant position detector 19 directly receives two beams of measuring light emitted by the first LED light source 6 and the second LED light source 9, and the first linear array CCD16 and the second linear array CCD17 alternately collect the measuring light reflected back after being emitted by the first LED light source 6 and the second LED light source 9 respectively;

step E, when the four-quadrant position detector 19 outputs the light spot displacement drift amounts E1 and E2 of the first LED light source 6 and the second LED light source 9, the first deflection mirror 20 generates an angle change to adjust the light beam direction of the first LED light source 6, so that the light spot displacement drift amount E1 is always 0, and the second deflection mirror 21 generates an angle change to adjust the light beam direction of the second LED light source 9, so that the light spot displacement drift amount E2 is always 0;

step f, when the plane mirror 5 rotates along with the measured object to generate a yaw angle and a pitch angle, the first linear array CCD16 outputs a light beam and light spot displacement value generated by the first multi-slit diaphragm 8, wherein the light spot is S1 away from the center of the image sensor, and the second linear array CCD17 outputs a light beam and light spot displacement value generated by the second multi-slit diaphragm 11, wherein the light spot is S2 away from the center of the image sensor;

step g, calculating alpha according to the displacement S1 of the light spot of the first linear array CCD16 and S1 ═ f · tan (2 alpha), wherein alpha is an angle of a yaw angle generated by a measured object; the displacement S2 of the light spot of the second linear array CCD17 is used to calculate β according to S2 ═ f · tan (2 β), where β is the angle at which the measured object generates the pitch angle.

The innovation point of the invention is that a fourth light splitting mirror 18 and a four-quadrant position detector 19 are added between a collimating objective lens group 4 and a plane reflecting mirror 5 as feedback detection modules, thereby not only measuring the drift amounts of light beams of two LED light sources in real time, but also measuring the light beam drift amount caused by the instability of an optical system in real time, compensating the light source drift amounts in real time by controlling a deflection mirror in a closed loop, and solving the problems of measurement instability caused by the light source drift amount and the instability of the optical system.