CN106931884A - The measuring system and its measuring method of Micro and nano manipulation platform Three Degree Of Freedom - Google Patents

Abstract

The invention relates to the field of laser detection technology of a micro-nano control platform, and discloses a three-degree-of-freedom measurement system for a micro-nano control platform. The micro-nano control platform includes a platform base and a displacement platform. The measurement system includes: The first laser interferometer and the second laser interferometer, and the optical assembly configured as a cross on the displacement platform, the optical assembly includes a first right-angle lens part and a second right-angle lens part; it also includes an image sensor and is arranged on the The spectroscopic mirror on the optical path of the outgoing light reflected by the first right-angle lens part, and the spectroscopic optical path reflected by the spectroscopic mirror is perpendicular to the photosensitive surface of the image sensor. The invention also provides a three-degree-of-freedom measurement method of the micro-nano control platform. The measurement system and the measurement method thereof provided by the invention can realize the measurement of three degrees of freedom in space and have high measurement accuracy.

Description

Three-degree-of-freedom measurement system and measurement method for micro-nano manipulation platform

technical field

The invention relates to the technical field of laser detection of a micro-nano control platform, in particular to a three-degree-of-freedom measurement system and a measurement method for a micro-nano control platform.

Background technique

With the development and application of micro-nano control technology, the micro-nano control platform with multiple degrees of freedom, especially the rotation degree of freedom, has attracted more and more attention, and the precise measurement of angular displacement and linear displacement is an important factor affecting its development.

Laser interferometers are widely used in various precision measurement systems due to their advantages such as high resolution, non-contact, little influence from the environment, and sensitive response. The laser interferometer performs displacement measurement based on the interference between the reference beam and the measuring beam. If the optical path difference of the two beams does not change, the detector will find a stable signal between the two poles of constructive and destructive interference. ; If there is a change in the optical path difference, the detector will find a change signal between the poles of constructive and destructive interference every time the optical path changes, and these changes will be calculated and used to measure the distance between the two optical paths difference between changes. Existing laser interferometers often can only measure a single translational motion or a single angular displacement. When there is a change in optical path difference, the laser interferometer cannot judge whether the change is caused by translational motion or by the rotation of the micro-nano control platform, so the micro-nano control platform is doing non-centered rotational motion, that is, existing translational motion In the case of rotational motion, it is impossible to decouple translational motion and angular displacement and measure them simultaneously.

Contents of the invention

(1) Technical problems to be solved

An object of the present invention is to provide a three-degree-of-freedom measurement system for a micro-nano control platform, which can measure translational motion and The angular displacement is decoupled and measured at the same time, and the measurement accuracy is high and the structure is simple.

Another object of the present invention is to provide a three-degree-of-freedom measurement method for a micro-nano manipulation platform.

(2) Technical solution

In order to solve the above technical problems, the present invention provides a three-degree-of-freedom measurement system for a micro-nano control platform, the micro-nano control platform includes a platform base and a displacement platform located on the platform base, which is characterized in that it includes:

a first laser interferometer and a second laser interferometer located on the first axis, the central axis of the emission hole of the first laser interferometer being collinear with the central axis of the emission hole of the second laser interferometer; and

An optical assembly configured as a cross on the displacement platform, the optical assembly includes a first right-angle mirror part corresponding to the first laser interferometer, the first right-angle mirror part includes a first right-angle mirror surface and a second right-angle mirror surface, and the first right-angle mirror surface The incident light emitted by a laser interferometer is parallel to the outgoing light after the incident light is reflected by the first right-angle mirror surface and the second right-angle mirror surface of the first right-angle lens part, and the optical assembly also includes a second right-angle light corresponding to the second laser interferometer. The lens part, the second right-angle lens part includes a first right-angle mirror surface and a second right-angle mirror surface, and the incident light emitted by the second laser interferometer and the incident light pass through the first right-angle mirror surface and the second right-angle mirror surface of the second right-angle lens part the reflected outgoing rays are parallel; and

It also includes an image sensor and a spectroscopic mirror arranged on the optical path of the outgoing light reflected by the first right-angle lens part, and the split optical path reflected by the spectroscopic mirror is perpendicular to the photosensitive surface of the image sensor.

Wherein, the optical assembly includes an optical assembly base arranged on a displacement platform, and four slots configured in a cross shape are arranged on the optical assembly base, and a glass sheet is arranged in each slot, wherein, close to the first laser The two glass sheets of the interferometer form a first right-angle mirror part, and the two glass sheets close to the second laser interferometer form a second right-angle mirror part, wherein the two glass sheets close to the first laser interferometer face the first laser interferometer One side of the instrument is coated with a reflective film, and the side of the two glass sheets close to the second laser interferometer facing the second laser interferometer is coated with a reflective film.

The present invention also provides a three-degree-of-freedom measurement method for a micro-nano control platform, which includes:

S1: Decompose the motion of the displacement platform into translational motion along the first axis, translational motion along the second axis perpendicular to the first axis, and rotational motion around the center point of the platform, and the translational distance of the displacement platform along the second axis is a ₁ , the translation distance along the first axis is a ₂ , and the rotation angle around the center point of the platform is θ;

S2: Measure the moving distance X ₁ of the outgoing light of the first right-angle lens part by the image sensor, and obtain the translational movement distance a ₁ =X ₁ /2 along the second axis;

S2: The optical path difference Y ₁₁ in the first direction on the first axis measured by the first laser interferometer; the optical path difference Y ₂₂ in the second direction on the first axis measured by the second laser interferometer; calculated by the following formula It is obtained that the optical path difference Y ₁ received by the first laser interferometer due to the translational movement of the displacement platform along the first axis, the optical path difference Y 2 received by the first laser interferometer due to the rotational movement of the displacement platform around the center point of the platform, and the optical path difference Y ₂ received by the first laser interferometer along the first axis The translational distance a ₂ of an axis;

Y ₁₁ =Y ₁ +Y ₂ ,

Y ₂₂ =-Y ₁ +Y ₂ ,

Y ₁ =2a ₂ ;

S4: in the said rotation movement around the center point of the platform, the first reflection point of the first right-angle mirror surface of the first right-angle mirror part before the displacement platform rotates and the first right-angle mirror surface of the first right-angle mirror part after the displacement platform rotates The distance between the first reflection point is m, the second reflection point of the second right-angle mirror surface of the first right-angle lens part before the displacement platform rotates and the second reflection point of the second right-angle mirror surface of the first right-angle lens part after the displacement platform rotates The distance between them is n, then let α=m/n, and it is known that L ₀ is the distance between the incident ray and the outgoing ray of the first right-angle lens part before the displacement platform does not move, then the displacement is calculated by the following formula Platform rotation angle θ:

(3) Beneficial effects

The three-degree-of-freedom measurement system of the micro-nano control platform provided by the present invention realizes displacement measurement in the direction of the second axis of the displacement platform through an image sensor, and realizes displacement measurement in the direction of the first axis through two laser interferometers on the first axis. And indirectly calculate the rotation angle of the micro-nano control platform, so as to realize the displacement and angle measurement of three degrees of freedom in space, which overcomes the limitations of existing detection devices and satisfies the real-time measurement of linear displacement and angular displacement with multiple degrees of freedom in space. Measure feedback. In addition, the measurement system has a simple structure and high measurement accuracy.

Description of drawings

Fig. 1 is a structural schematic diagram of a three-degree-of-freedom measurement system of a micro-nano control platform according to the present invention;

Fig. 2 is a top view of a three-degree-of-freedom measurement system of a micro-nano manipulation platform in Fig. 1;

Fig. 3 is a schematic structural view of a preferred embodiment of the optical assembly of the measuring system in Fig. 1;

Fig. 4 is the schematic diagram before and after the movement of the displacement platform in Fig. 1;

Fig. 5 is the schematic diagram of the motion decomposition of the displacement platform in Fig. 4, wherein (a) is the structural representation before the displacement platform moves; (b) is the schematic diagram of the decomposed displacement platform moving along the X axis; (c) is the decomposed A schematic diagram of translation of the displacement platform along the Y axis; and (d) a schematic diagram of the rotation of the decomposed displacement platform around the center point of the displacement platform;

Fig. 6 is a schematic diagram of the incident light and the outgoing light before and after the displacement platform is translated along the X axis in Fig. 5(b);

Fig. 7 is a schematic diagram of the incident light and the outgoing light before and after the displacement platform is translated along the Y axis in Fig. 5(c);

FIG. 8 is a schematic diagram of incident light and outgoing light before and after the displacement platform rotates around the center point of the platform in FIG. 5( d ).

In the figure, 1: first laser interferometer; 2: second laser interferometer; 3: image sensor; 4: displacement platform; 5: platform base; 6: optical component; 601: optical component base; 602: glass sheet; 603: fixed bracket; 604: movable bracket; 605: bolt.

detailed description

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", The orientation or positional relationship indicated by "radial direction", "circumferential direction", "X axis" and "Y axis" are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than Nothing indicating or implying that a referenced device or element must have a particular orientation, be constructed, and operate in a particular orientation should therefore not be construed as limiting the invention.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

In the present invention, unless otherwise clearly specified and limited, terms such as "installation", "connection", "connection" and "fixation" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection , or integrated; can be mechanically connected, can also be electrically connected or can communicate with each other; can be directly connected, can also be indirectly connected through an intermediary, can be the internal communication of two components or the interaction relationship between two components, unless expressly defined otherwise. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

Fig. 1 and Fig. 2 show a preferred embodiment of a three-degree-of-freedom measurement system of a micro-nano manipulation platform according to the present invention. As shown in Figure 1, the micro-nano manipulation platform includes a platform base 5 and a displacement platform 4 on the platform base 5, and the measurement system includes: a first laser interferometer 1 and a second laser interferometer located on the first axis (Y axis) Interferometer 2, the central axis of the emission hole of the first laser interferometer 1 is collinear with the central axis of the emission hole of the second laser interferometer 2; The component 6 includes a first right-angle lens part corresponding to the first laser interferometer 1, the first right-angle lens part includes a first right-angle mirror surface and a second right-angle mirror surface, and the incident light emitted by the first laser interferometer 1 is in line with the incident light The outgoing rays reflected by the first right-angle mirror surface and the second right-angle mirror surface of the first right-angle lens part are parallel. The initial angle of incidence of the mirror is 45°. The optical assembly also includes a second right-angle lens part corresponding to the second laser interferometer 2, the second right-angle lens part includes a first right-angle mirror surface and a second right-angle mirror surface, and the incident light emitted by the second laser interferometer and the incident light The outgoing rays reflected by the first right-angle mirror surface and the second right-angle mirror surface of the second right-angle mirror part are parallel. In this embodiment, the initial incident angle of the incident light emitted by the second laser interferometer 2 incident on the first right-angle mirror surface of the second right-angle mirror part is 45°.

In addition, the measurement system also includes an image sensor 3 and a spectroscope 7 arranged on the optical path of the outgoing light reflected by the first right-angle mirror part.

The three-degree-of-freedom measurement system of the micro-nano control platform provided by the present invention can realize displacement measurement in the direction of the second axis (X-axis) perpendicular to the Y-axis through the image sensor 3 and the beam splitter 7, and through two laser beams on the Y-axis The interferometer can realize the displacement measurement in the Y direction, and can indirectly calculate the rotation angle of the micro-nano control platform (the specific calculation method will be described below), so as to realize the displacement and angle measurement of three degrees of freedom in space, which overcomes the The limitations of existing detection devices meet the real-time measurement feedback of linear displacement and angular displacement with multiple degrees of freedom in space. In addition, the measurement system has a simple structure and high measurement accuracy.

Specifically, as shown in FIG. 3 , the optical assembly 6 includes an optical assembly base 601 arranged on the displacement platform 1, and four slots configured in a cross shape are arranged on the optical assembly base 601, and in each slot Both are provided with a glass sheet 602, wherein, the two glass sheets 602 (the first glass sheet and the second glass sheet) close to the first laser interferometer 1 in the optical assembly 6 are coated on the side facing the first laser interferometer 1 Reflective film, two glass sheets 602 (third glass sheet and fourth glass sheet) close to the second laser interferometer 2 are coated with reflective film on the side facing the second laser interferometer 2 .

Preferably, the optical assembly further includes two fixed brackets 603 located on the optical assembly base 601 and two movable brackets 604 capable of moving in the X-axis direction, one of the fixed brackets 603 respectively abuts against the first laser interferometer 1 On the two glass sheets (the first glass sheet and the second glass sheet), another fixed bracket 603 is attached to the two glass sheets (the third glass sheet and the fourth glass sheet) near the second laser interferometer 2 respectively , one of the movable brackets 604 abuts on the second glass sheet and the third glass sheet respectively, and the other movable bracket 604 abuts on the first glass sheet and the fourth glass sheet respectively, the cross sections of the fixed bracket 603 and the movable bracket 604 are both Isosceles right-angled shape. A bolt 605 is provided at the outer end of the movable bracket 604, and a threaded hole matched with the bolt 605 is provided on the optical assembly base 601. When the head of the bolt is screwed, the bolt shank abuts on the movable bracket 604, so that the movable bracket 604 slides along the X direction, so that the corresponding glass sheet is fixed between the corresponding movable support 603 and the fixed support 604 .

In this embodiment, the first laser interferometer 1 and the second laser interferometer 2 are supported and connected to the platform base 5 respectively.

The invention also discloses a method for measuring three degrees of freedom of a micro-nano control platform, which comprises the following steps:

S1: Decompose the motion of the micro-nano manipulation platform (as shown in Figure 4) into translational motion of the displacement platform 4 along the X axis (as shown in Figure 5(b)), and translational motion along the Y axis (as shown in Figure 5(c) )) and the rotational motion around the center of the platform (as shown in Figure 5(d)), let the translational distance of the displacement platform 4 along the X-axis be a ₁ , the translational distance along the Y-axis be a ₂ and the translational distance around the platform center The rotation angle of the point is θ;

S2: Measure the moving distance X ₁ of the outgoing light of the first right-angle lens part by the image sensor, and obtain the translational movement distance a ₁ of the X-axis = X ₁ /2;

Specifically, as shown in FIG. 6, _L0 is the distance between the incident light AB and the outgoing light CD of the first right-angle lens part when the displacement platform ₄ is not moving; L1 is the distance between the displacement platform 4 and the translational movement along the X axis. _The distance X ₁ between the incident ray _AE and the outgoing ray FG of the _first right-angle lens part _; The distance the light moves can obtain the displacement a ₁ =X ₁ /2 of the micro-nano manipulation platform along the X-axis.

When the displacement platform 4 moves along the X axis, the change of the optical path difference in the Y direction is 0, that is, when the displacement platform 4 moves along the X axis, the outputs of the first laser interferometer 1 and the second laser interferometer 2 have no change.

S3: The first optical path difference Y ₁₁ of the Y axis is measured by the first laser interferometer 1; the second optical path difference Y 22 of the Y axis is measured by the second laser interferometer 2, and the first optical path difference Y ₂₂ is calculated by the following formula The optical path difference Y 1 received by the laser interferometer 1 due to the translational movement of the displacement platform 4 along the Y axis, the optical path difference Y ₂ received by the first laser interferometer ₁ due to the rotational movement of the displacement platform around the center point of the platform, and the optical path difference along the Y axis Translation distance a ₂ (as shown in Figure 7);

Y ₁₁ =Y ₁ +Y ₂ ,

Y ₂₂ =-Y ₁ +Y ₂ ,

Y ₁ =2a ₂ ;

S4: set in the described rotational movement around the center point of the platform, as shown in Figure 8, the first reflection point B of the first right-angle lens part before the displacement platform 4 rotates and the first reflection point B of the first right-angle lens part after the displacement platform 4 rotates The distance between a reflection point E is m, and the distance between the second reflection point C of the first right-angle mirror part before the displacement platform 4 rotates and the second reflection point F of the first right-angle mirror part after the displacement platform 4 rotates is n , then let α=m/n, and it is known that L ₀ is the distance between the incident ray AB and the outgoing ray CD of the first right-angle lens part before the displacement platform 4 does not move (as shown in Figure 7), then by the following formula Calculate the rotation angle θ of the displacement platform 4:

When the displacement platform 4a moves along the Y axis, the optical path difference Y 1 received by the first laser interferometer 1 due to the translational movement of the displacement platform 4a along the Y axis, and the optical path difference Y ₁ received by the first laser interferometer 1 due to the rotational movement of the displacement platform around the center point of the platform The optical path difference Y ₂ and the translational distance a ₂ along the Y axis (as shown in Figure 8), then Y ₁ , Y ₂ and a ₂ satisfy the following formula;

Y ₁₁ =Y ₁ +Y ₂ ,

Y ₂₂ =-Y ₁ +Y ₂ ,

Y ₁ =2a ₂ ;

Before and after the rotational movement of the displacement platform 4b around the center point of the platform, when the direction and position of the incident light AB remain unchanged, the direction and position of the outgoing light CD also do not change.

In Fig. 8, a horizontal straight line KN is drawn through point K, an extension line of GF is drawn through point F, and the horizontal line passing through point K intersects at point N.

(1) Set the rotation angle of the displacement platform 4 as θ, when the rotation angle θ is 0°, the incident ray is AB, the outgoing ray is CD, the incident angle of the incident ray is 45°, and the exit angle of the outgoing ray CD is also 45° °, so EB//CG.

(2) When the rotation angle θ is not 0°, the incident ray is AE, the outgoing ray is FG, and the incident angle of the incident ray is 45°+θ. At this time, ∠KEF=45°-θ. In the right angle ΔEKF, ∠ KEF＝45°-θ, ∠EKF＝90°, we can get ∠EFK＝45°+θ.

In Fig. 8, ∠FKN=45°-θ, ∠GHM=∠EFK=45°+θ, ∠KFN=∠GFM=45°+θ. So ∠KNF=180°-∠FKN-∠KFN=90°. The extension line FN//EB of GF is parallel, so GF//EB.

The distance from AB to CD is BC=L ₁ . The distance from FG to EB is EG, ∠GEF＝90°-∠BEK-∠KEF＝2θ, and EG is perpendicular to GF, so EG＝EF×cos2θ, where

EF=EK/cos(45°-θ),

BK=BC×cos45°,

EG=L ₁ can be obtained.

Therefore CD and FG are parallel and the distance from CD to AB is equal to the distance from FG to AB, so the straight line CD and the straight line FG coincide.

The optical path difference after the displacement platform 4 rotates is: Y ₂ =EF+FC-EB-BC. It can be seen from geometric knowledge that △EOB≈△COF (that is, the two shaded triangles in the figure are similar), and the similarity ratio is set as

∠GEF=2×θ;

From the above conditions, the following equation can be obtained:

In ΔFJK, ∠BEK＝45°-θ, ∠EKB＝θ, we know from the law of sine:

The joint solution of equations (1) and (2) can obtain the rotation angle θ of the micro-nano manipulation platform.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention within.

Claims (3)

1. a kind of measuring system of Micro and nano manipulation platform Three Degree Of Freedom, the Micro and nano manipulation platform includes platform base and is located at Displacement platform on the platform base, it is characterised in that including：

First laser interferometer and second laser interferometer on first axle, in the launch hole of first laser interferometer Heart axis is conllinear with the central axis of the launch hole of second laser interferometer；And

It is located on displacement platform and is configured to criss-cross optical module, the optical module includes corresponding with first laser interferometer First right angle optic portion, the first right angle optic portion includes the first right angle minute surface and the second right angle minute surface, and first laser The incident ray of interferometer transmitting is with the incident ray through the first right angle minute surface of the first right angle optic portion and the second prism square Emergent ray after the reflection of face is parallel, and optical module also includes the second right angle optic portion corresponding with second laser interferometer, The second right angle optic portion includes the first right angle minute surface and the second right angle minute surface, and the incident light that second laser interferometer is launched Line is with the incident ray through the emergent ray after the first right angle minute surface and the second right angle mirror-reflection of the second right angle optic portion It is parallel；And

Also include dividing in the light path of imageing sensor and the emergent ray being arranged on after being reflected through the first right angle optic portion Light microscopic is vertical through the light splitting optical path of dichroic mirror and the photosurface of described image sensor.

2. measuring system as claimed in claim 1, it is characterised in that optical module includes the optics being arranged on displacement platform Unitized substructure, is provided with optical module base and is configured to criss-cross four draw-in grooves, and glass is provided with each draw-in groove Glass piece, wherein, two sheet glass near first laser interferometer form the first right angle optic portion, near second laser interference Two sheet glass of instrument form the second right angle optic portion, wherein, two sheet glass near first laser interferometer are towards the The one side of one laser interferometer is coated with reflective membrane, and two sheet glass near second laser interferometer are dry towards second laser The one side of interferometer is coated with reflective membrane.

3. a kind of measuring method of Micro and nano manipulation platform Three Degree Of Freedom, it is characterised in that including：

S1：By the Kinematic Decomposition of displacement platform into the translational motion along first axle, along the second axis vertical with first axle Translational motion and the rotary motion around Platform center point, if displacement platform along second axis translation distance be a₁, along first The translation distance of axis is a₂And around Platform center point the anglec of rotation be θ；

S2：The displacement X of the emergent ray of the first right angle optic portion is measured by imageing sensor₁, draw along second axis Translational motion is apart from a₁=X₁/2；

S2：The first direction optical path difference Y on first axle is measured by first laser interferometer₁₁；Measured by second laser interferometer Second direction optical path difference Y on first axle₂₂；First laser interferometer is calculated because displacement platform is along by below equation The optical path difference Y that the motion of one axis translation is received₁, first laser interferometer connects because of displacement platform around Platform center point rotary motion The optical path difference Y for receiving₂With the translation distance a along first axle₂；

Y₁₁=Y₁+Y₂,

Y₂₂=-Y₁+Y₂,

Y₁=2a₂；

S4:Described in being located in the rotary motion of Platform center point, the first of displacement platform rotation preceding first right angle optic portion First reflection of the first right angle minute surface of the first right angle optic portion after first pip and the displacement platform rotation of right angle minute surface The distance between point is m, the second pip of the second right angle minute surface of displacement platform rotation preceding first right angle optic portion and position It is n to move the distance between second pip of the second right angle minute surface of the first right angle optic portion after platform rotates, then make α=m/ N, and known L₀For displacement platform does not move the distance between incident ray and emergent ray of preceding first right angle optic portion, then The anglec of rotation θ of displacement platform is calculated by following formula：

$Y_2=\frac{L_0}{cos2\mathrm{\θ}}+\frac{L_0\×\mathrm{\α}}{1+\mathrm{\α}}tan2\mathrm{\θ}-\frac{L_0}{1+\mathrm{\α}}tan2\mathrm{\θ}-L_0;$