CN112129230A - Two-dimensional grating for high-resolution and high-precision plane displacement measurement - Google Patents
Two-dimensional grating for high-resolution and high-precision plane displacement measurement Download PDFInfo
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Abstract
A two-dimensional grating for high resolution and high precision planar displacement measurement, comprising: disk body and code marking. Wherein, the disk body is made of glass material plated with an opaque coating film or opaque metal material; the coding marked lines are a group of transparent marked lines which are arranged according to a specific code. When x represents a coding element in the horizontal dimension and y represents a coding element in the vertical dimension, the coding mark lines include four coding mark lines, each of which represents { x ═ 0, y ═ 0}, { x ═ 1, y ═ 1}, { x ═ 0, and y ═ 1}, and all the coding mark lines have the same horizontal spacing and the same vertical spacing. When the code disc is imaged by the image sensor, the coded value can be identified, and then the transverse and longitudinal displacement information is obtained through the decoding table. Meanwhile, the distances between all the coding marked lines are the same, so that the subdivision operation of displacement can be conveniently realized through centroid operation. The invention can realize high-resolution and high-precision two-dimensional displacement measurement by matching with image identification.
Description
Technical Field
The invention relates to the field of photoelectric displacement precision measurement, in particular to a two-dimensional grating for high-resolution and high-precision plane displacement measurement.
Background
The digital photoelectric displacement measurement is a high-precision measurement technology integrating light collector and electricity, and becomes a key technology in the fields of industrial manufacturing, aerospace, military equipment and the like due to the advantages of high precision, high resolution, wide measurement range, easiness in butt joint with digital equipment and the like. Meanwhile, with the increasing development of the production and manufacturing industry, higher requirements are put forward on the digital displacement measurement technology, and the method mainly comprises the following steps: high measurement accuracy and high resolution. The research on high-resolution and high-precision plane displacement measurement is popular in the field of basic manufacturing research and has important significance.
For the existing developed ultra-precise displacement sensor, if the sensor is applied to the field of two-dimensional or multi-dimensional displacement measurement, a plurality of sets of sensors are matched with a corresponding measurement system. For two-dimensional displacement measurement, one displacement sensor cannot be used alone unless two sets of sensors are combined to complete measurement. Two-dimensional displacement measurement is needed in many fields, and a general displacement sensor can only solve the problem of one-dimensional displacement measurement. At present, the two-dimensional displacement of a measuring plane is mainly divided into two forms. One is that one-dimensional displacement sensors are respectively arranged in the x direction and the y direction, and plane two-dimensional displacement measurement is realized by respectively measuring the displacement in the x direction and the y direction; the other is to adopt an integrated two-dimensional displacement sensor and adopt a set of displacement sensors to finish two-dimensional displacement measurement.
According to analysis, when two sets of one-dimensional displacement sensors are adopted, the installation precision is difficult to guarantee, and a large measurement error can be introduced. And the adoption of an integrated two-dimensional measurement mode is the current priority scheme. In order to realize two-dimensional plane measurement, the key is to research a two-dimensional grating code disc. In the traditional technology center, the absolute plane displacement measurement cannot be well solved by a moire fringe method, a magnetic grid method and the like.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides the two-dimensional grating for high-resolution and high-precision plane displacement measurement, and the image recognition of the coding marked line on the scale can be simply and conveniently realized through the cooperation of the image sensor, so that the high-resolution and high-precision two-dimensional plane displacement measurement is realized.
The technical scheme adopted by the invention for solving the technical problem is as follows:
a two-dimensional grating for high resolution and high precision planar displacement measurement, the two-dimensional grating comprising: the disc body and the coding marked line arranged on the disc body; the tray body is a square tray body made of metal or glass material plated with a light-proof film; the code reticle includes four light-transmitting rectangles, wherein the horizontal code value is x, and the vertical code value is y, that is, the code values of the four rectangles are { x ═ 0, y ═ 0}, { x ═ 1, y ═ 1} and { x ═ 0, y ═ 1 }.
Preferably, among the four rectangles, there are rectangles and squares; the length of the long side of the rectangle is 2 times of the length of the short side.
Preferably, the range of the transverse and longitudinal directions of the disc body is L, N code marked lines are arranged in the range, the distance between the central points of the adjacent code marked lines is L/N, and the two lengths of the code marked lines are respectively set as follows: a and B, wherein L/4N < a < L/2N, B ═ a/2.
Preferably, the four rectangles have the following structures:
the length of the first shape is B, and the height of the first shape is B;
the length of the second shape is A, and the height of the second shape is B;
the length of the shape III is A, and the height of the shape III is A;
the length of the shape four is B, and the height of the shape four is A.
Preferably, the coding marked line adopts a corresponding shape to code according to the arrangement sequence of the horizontal coding value and the vertical coding value; the horizontal coding and the vertical coding are respectively coded according to a shift coding mode;
assuming that the number of bits of the horizontal code is n, and the initial code value of the initial 0 th code to the nth code is {0,0,0, …,1}, the ith code can be represented as XiI.e. by
In the formula (I), the compound is shown in the specification,
representing an exclusive OR operation, a1～anRespectively operating coefficients, wherein the values of the coefficients are '1' or '0', and not all the coefficients are '0'; calculating the code value of each bit code in turn, and selecting the coefficient a appropriately1～anIs calculated to obtain 2nAn encoded value.
When n is 3, a1～a3＝{1,0,1}；
When n is 4, a1～a4＝{1,0,0,1}；
When n is 5, a1～a5＝{1,0,0,1,0}；
When n is 6, a1～a6＝{1,0,0,0,0,1}；
When n is 7, a1～a7＝{1,0,0,0,0,0,1}；
When n is 8, a1～a8＝{1,0,0,0,1,1,1,0}；
When n is 9, a1～a9＝{1,0,0,0,0,1,0,0,0}；
When n is 10, a1～a10＝{1,0,0,0,0,0,0,1,0,0}；
In the code values obtained by calculation according to a formula, each group of adjacent n code values form a group of codes, n groups of different codes are in total, and the corresponding i value is a decoded value; accordingly, the value of the vertical code is calculated according to the formula.
Preferably, the starting position of the horizontal coding value is located at the leftmost side or the rightmost side of the disk body, and then the horizontal coding value is sequentially arranged according to the coding sequence; the initial position of the longitudinal coding value is positioned at the uppermost side or the lower side of the disk body and then arranged according to the coding sequence in sequence.
The invention has the beneficial effects that: the invention provides a two-dimensional grating for high-resolution and high-precision plane displacement measurement, which can simply and conveniently realize image recognition of a code marking on a scale through the cooperation of an image sensor, thereby realizing high-resolution and high-precision two-dimensional plane displacement measurement.
Drawings
FIG. 1 is a schematic diagram of a disk structure of a two-dimensional grating for high-resolution and high-precision plane displacement measurement according to the present invention.
FIG. 2 is a schematic diagram of a coding reticle structure of a two-dimensional grating for high resolution and high precision planar displacement measurement according to the present invention.
Fig. 3 is a schematic diagram of a two-dimensional plane displacement measuring device.
Fig. 4 is a schematic diagram of a (16 × 16) two-dimensional grating two-dimensional displacement calculation disclosed in the embodiment of the present invention.
In the figure: 1. the device comprises a disc body, 2, a coding reticle, 21, a first shape, 22, a second shape, 23, a third shape, 24, a fourth shape, 3, an image sensor, 4, a processing circuit, 5, an imaging lens, 6, an illumination light source, 7 and a support.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Referring to fig. 1, a (16 × 16) bit encoded two-dimensional grating disclosed in an embodiment of the present invention includes: disk body 1, code marking 2. The coded graticule 2 is marked on the disc body 1. The disk body 1 is an opaque square disk and is made of glass materials or metal materials plated with opaque films.
Referring to fig. 2, a schematic diagram of a shape of a coding reticle disclosed in the embodiment of the present invention includes: shape one 21, shape two 22, shape three 23, shape four 24. If the horizontal code value is x and the vertical code value is y, then the code value represented by the shape one is { x ═ 0, y ═ 0}, the shape two is { x ═ 1, y ═ 0}, the shape three is { x ═ 1, y ═ 1}, and the shape four is { x ═ 0, y ═ 1 }.
The first shape 21, the second shape 22, the third shape 23 and the fourth shape 24 are respectively four rectangles with different lengths and widths. And the measuring range length in the direction of the transverse axis is L, N coding intervals are arranged in the measuring range, and the distance between adjacent coding marked lines in the transverse axis is L/N. The width in the x-axis direction includes two widths: width one is denoted as a and width two is denoted as B. A is twice the width of B. The same is true for the vertical axis.
Preferably, L/4N < a < L/2N, B ═ a/2.
The length of the first shape 21 is B, and the height of the first shape is B;
the length of the second shape 22 is A, and the height of the second shape is B;
the length of the third shape 23 is A, and the height of the third shape is A;
the shape four 24 has a length B and a height a.
And the coding marked lines 2 are coded by adopting corresponding shapes according to the arrangement sequence of the transverse coding numerical values and the longitudinal coding numerical values. The horizontal coding and the vertical coding are coded according to a shift coding mode respectively.
Assuming that the number of bits of the horizontal codes is n and the code values of the initial 0 th code to the nth code are (initial code values) {0,0,0, …,1}, the ith code can be represented as XiI.e. by
In the formula (I), the compound is shown in the specification,
representing an exclusive OR operation, a1～anThe coefficients are respectively calculated to have values of "1" or "0", and are not all "0". Calculating the code value of each bit code in turn, and selecting the coefficient a appropriately1～anCan be calculated to obtain 2nAn encoded value.
Preferably, when n is 3, a1～a7＝{1,0,1}；
Preferably, when n is 4, a1～a7＝{1,0,0,1}；
Preferably, when n is 5, a1～a7＝{1,0,0,1,0}；
Preferably, when n is 6, a1～a7＝{1,0,0,0,0,1}；
Preferably, when n is 7, a1～a7＝{1,0,0,0,0,0,1}；
Preferably, when n is 8, a1～a8＝{1,0,0,0,1,1,1,0}；
Preferably, when n is 9, a1～a9＝{1,0,0,0,0,1,0,0,0}；
Preferably, when n is 10, a1～a10＝{1,0,0,0,0,0,0,1,0,0}.
And (2) according to the code values obtained by the formula (1), each group of adjacent n code values form a group of codes, n groups of different codes are shared, and the corresponding i value is the decoded value.
Accordingly, the value of the vertical code is also calculated according to equation (1).
The initial positions of the encoding values are located at the leftmost side (or the right side) of the disk body 1, and then are sequentially arranged according to the encoding sequence.
As shown in fig. 3, the two-dimensional plane displacement measuring device disclosed in the embodiment of the present invention includes: the device comprises a disc body 1, a coding reticle 2, an image sensor 3, a processing circuit 4, an imaging lens 5, an illumination light source 6 and a support 7. The support 7 drives the image sensor 3 to move two-dimensionally on a plane.
Light rays emitted by the illumination light source 5 are reflected by the disc body 1, and the patterns of the coding reticle 2 are mapped into the image sensor 3 through the imaging lens 5, so that the coding reticle 2 is imaged.
The image sensor 3 sends the received image to the processing circuit 4, and realizes decoding and subdivision calculation according to the coded mark lines in the image, thereby realizing plane two-dimensional displacement measurement with high resolution and high precision.
Referring to fig. 4, a schematic diagram of a (16 × 16) two-dimensional displacement calculation disclosed in the embodiment of the present invention. To achieve accurate coding, the field of view of the image sensor 3 should include at least 4 × 4 of the encoded reticle 2. A coordinate system is set with the transverse central axis of the image field of view as the x-axis and the longitudinal central axis as the y-axis.
When the transverse displacement is obtained, the width of the transverse code is read, the numerical value represented by the current marking in the transverse direction is judged according to the width of each marking, and a decoding table is inquired to obtain a decoding value Ax. In the fourth drawing, the horizontal coding is "1101". Then, the centroids of the code reticle 2 adjacent to the two sides of the y-axis are calculated, the centroids are x1 and x2, respectively, and then the values of the lateral subdivision can be expressed as:
in the formula, etaxBy a subdivision factor, ηxThe larger the longitudinal resolution that can be achieved. By checking the decode value AxAnd a subdivision value BxCan obtain the final transverse measurement value Cx＝Ax·ηx+Bx。
Similarly, when the longitudinal displacement is obtained, the width of the longitudinal code is read, the numerical value represented by the current marking in the transverse direction is judged according to the width of each marking, and the decoding table is inquired to obtain the decoding value Ax. In fig. four, the vertical code is "0000". Then, the centroids of the code reticle 2 adjacent to both sides of the x-axis are calculated, the centroids are y1 and y2, respectively, and then the values of the longitudinal subdivision can be expressed as:
in the formula, etayBy a subdivision factor, ηyThe larger the longitudinal resolution that can be achieved. By checking the decode value AyAnd a subdivision value ByCan obtain the final transverse measurement value Cy＝Ay·ηy+By。
The two-dimensional resultant displacement is then expressed as
The invention has the advantages of easy realization of absolute high-resolution and high-precision displacement measurement, and easy realization of a high-resolution displacement subdivision algorithm because the transverse/longitudinal distances of all the marked lines in the plane grating are the same.
Claims (6)
1. A two-dimensional grating for high resolution and high precision planar displacement measurement, the two-dimensional grating comprising: the disc body and the coding marked line arranged on the disc body; the tray body is a square tray body made of metal or glass material plated with a light-proof film; the code reticle includes four light-transmitting rectangles, wherein the horizontal code value is x, and the vertical code value is y, that is, the code values of the four rectangles are { x ═ 0, y ═ 0}, { x ═ 1, y ═ 1} and { x ═ 0, y ═ 1 }.
2. A two-dimensional grating for high resolution and high accuracy planar displacement measurement according to claim 1, wherein of the four rectangles, there are rectangles and squares; the length of the long side of the rectangle is 2 times of the length of the short side.
3. The two-dimensional grating for high resolution and high precision plane displacement measurement of claim 1, wherein the range of the disc body in the horizontal and vertical directions is L, N code marks are provided in the range of the range, the distance between the center points of the adjacent code marks is L/N, and the two lengths of the code marks are respectively: a and B, wherein L/4N < a < L/2N, B ═ a/2.
4. A two-dimensional grating for high resolution and high precision planar displacement measurement according to claim 1 or 3, wherein the four rectangular structures are:
the length of the first shape is B, and the height of the first shape is B;
the length of the second shape is A, and the height of the second shape is B;
the length of the shape III is A, and the height of the shape III is A;
the length of the shape four is B, and the height of the shape four is A.
5. A two-dimensional grating for high resolution and high precision planar displacement measurement according to claim 1 or 3, wherein the coded reticle is coded in a corresponding shape according to the arrangement order of the horizontal coded values and the vertical coded values; the horizontal coding and the vertical coding are respectively coded according to a shift coding mode;
assuming that the number of bits of the horizontal code is n, and the initial code value of the initial 0 th code to the nth code is {0,0,0, …,1}, the ith code can be represented as XiI.e. by
In the formula (I), the compound is shown in the specification,
representing an exclusive OR operation, a1～anAre respectively an operational coefficient, the value of which is "1" or "0", and not all "0"; calculating the code value of each bit code in turn, and selecting the coefficient a appropriately1～anCan be calculated to obtain 2 at mostnA code value Xi。
When n is 3, a1～a3＝{1,0,1}；
When n is 4, a1～a4＝{1,0,0,1}；
When n is 5, a1～a5＝{1,0,0,1,0}；
When n is 6, a1～a6＝{1,0,0,0,0,1}；
When n is 7, a1～a7＝{1,0,0,0,0,0,1}；
When n is 8, a1～a8＝{1,0,0,0,1,1,1,0}；
When n is 9, a1～a9＝{1,0,0,0,0,1,0,0,0}；
When n is 10, a1～a10＝{1,0,0,0,0,0,0,1,0,0}；
Of the code values calculated according to the formula, each group of adjacent n code values { X }i,Xi+1,…,Xi+n-1Forming a group of codes, wherein n groups of different codes are in total, and the corresponding value i is a decoding value; accordingly, the value of the vertical code is calculated according to the formula.
6. The two-dimensional grating for high-resolution and high-precision plane displacement measurement according to claim 1, wherein the starting position of the transverse code values is located at the leftmost side or the rightmost side of the disc body and then arranged according to the coding sequence in sequence; the initial position of the longitudinal coding value is positioned at the uppermost side or the lower side of the disk body and then arranged according to the coding sequence in sequence.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113029001A (en) * | 2021-03-18 | 2021-06-25 | 中国科学院长春光学精密机械与物理研究所 | Linear displacement measuring device and method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2535686A2 (en) * | 2011-06-13 | 2012-12-19 | Mitutoyo Corporation | Optical encoder including displacement sensing normal to the encoder scale grating surface |
| CN103033141A (en) * | 2012-12-28 | 2013-04-10 | 中国科学院长春光学精密机械与物理研究所 | Two-dimensional displacement measurement device |
| US8829420B2 (en) * | 2010-06-09 | 2014-09-09 | Nikon Corporation | Two dimensional encoder system and method |
| CN107121072A (en) * | 2017-05-22 | 2017-09-01 | 合肥工业大学 | Two-dimentional absolute displacement encoder |
| CN107525471A (en) * | 2017-08-21 | 2017-12-29 | 合肥工业大学 | Two-dimentional absolute encoding Three-degree-of-freedom motion platform measuring system |
-
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8829420B2 (en) * | 2010-06-09 | 2014-09-09 | Nikon Corporation | Two dimensional encoder system and method |
| EP2535686A2 (en) * | 2011-06-13 | 2012-12-19 | Mitutoyo Corporation | Optical encoder including displacement sensing normal to the encoder scale grating surface |
| CN103033141A (en) * | 2012-12-28 | 2013-04-10 | 中国科学院长春光学精密机械与物理研究所 | Two-dimensional displacement measurement device |
| CN107121072A (en) * | 2017-05-22 | 2017-09-01 | 合肥工业大学 | Two-dimentional absolute displacement encoder |
| CN107525471A (en) * | 2017-08-21 | 2017-12-29 | 合肥工业大学 | Two-dimentional absolute encoding Three-degree-of-freedom motion platform measuring system |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113029001A (en) * | 2021-03-18 | 2021-06-25 | 中国科学院长春光学精密机械与物理研究所 | Linear displacement measuring device and method |
| CN113029001B (en) * | 2021-03-18 | 2022-02-11 | 中国科学院长春光学精密机械与物理研究所 | Linear displacement measuring device and method |
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