KR101191458B1

KR101191458B1 - Structure Deformation Measurement System and method

Info

Publication number: KR101191458B1
Application number: KR20100104837A
Authority: KR
Inventors: 명현; 전해민
Original assignee: 한국과학기술원
Priority date: 2010-10-26
Filing date: 2010-10-26
Publication date: 2012-10-18
Also published as: KR20120043502A

Abstract

Structure displacement measuring systems and methods are provided. The structure displacement measuring system controls the irradiation angle of the first laser irradiator so that the laser beam irradiated from the first laser irradiator is irradiated inside the second screen, and the laser beam irradiated from the second laser irradiator is inside the first screen. The irradiation angle of the second laser irradiator is controlled to be irradiated, and the relative displacement of the first structure with respect to the second structure using the first image generated by photographing the first screen and the second image generated by photographing the second screen. Estimate This makes it possible to adjust the position of the points inside the screen by controlling the direction of the irradiating lasers for the measurement of the structure displacement, so that the displacement measurement of the structure is always possible in any external situation.

Description

Structure Deformation Measurement System and Method

The present invention relates to a structure displacement measuring system and method, and more particularly to a system and method capable of measuring the displacement of a large structure.

Civil or architectural structures are exposed to external loads such as traffic, earthquakes, gusts, Therefore, in the case of civil engineering or building structure, reasonable and accurate design construction is important, but proper maintenance work is very important for maintaining the optimum usability of the structure and extending the life of the structure. In particular, with the recent increase in large structures such as high-rise buildings and long bridges, the importance of the Structural Health Monitoring System has increased. Such a structural safety diagnosis system can improve the stability of the structure by measuring, analyzing and diagnosing the dynamic behavior of the structures such as bridges and buildings. The structure safety diagnosis system requires many techniques such as structure damage identification method, data acquisition and transmission method, and the like.

Structural safety diagnostic systems typically use inclinometers, acceleration sensors, strain gauges, PZT sensors, etc. to measure structure displacement. Although the measurement of displacement is very important, it has not been studied much because of the huge size of the structure and the difficulty of access. One of the most commonly used methods of structural displacement measurement is the use of contact-type sensors that require a linear variable differential transformer (LVDT) and a stable reference point at the bottom. However, this type of contact sensor is not practical because it requires a reference point to be observed from the outside.

Displacement measurement using vision is also one of the active research areas. Most of the currently developed vision methods are to install a target on the structure to be measured and observe the movement of the target by using a high-performance camera at a remote reference point. This method also requires a reference point and the distance between the target and the camera is far. Because of this, it is difficult to measure due to the weather.

Accordingly, there is a growing need for vision and laser-based mobile robotic devices and methods that do not require a reference point and are robust to external environmental changes such as weather and illumination.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a structure displacement measuring system and method which can adjust the point positions inside the screen by controlling the direction of the laser beams for measuring the structure displacement. In providing.

Another object of the present invention is to provide a structure displacement measuring system and method capable of more accurate structure displacement measurement based on initial offset correction.

In accordance with an aspect of the present invention, a structure displacement measuring system includes: a first laser irradiator installed on a first structure and irradiating a laser beam to a second screen attached to the second structure; A second laser irradiator installed on the second structure and irradiating a laser beam to a first screen attached to the first structure; A first camera photographing the first screen to generate a first image; A second camera photographing the second screen to generate a second image; And controlling an irradiation angle of the first laser irradiator so that the laser beam irradiated from the first laser irradiator is irradiated inside the second screen, and the laser beam irradiated from the second laser irradiator is irradiated inside the first screen. And a control module for controlling the irradiation angle of the second laser irradiator to estimate the relative displacement of the first structure with respect to the second structure using the first image and the second image.

Preferably, the control module corrects the displacement estimated in the estimating step by using a calibration matrix for initial offset correction.

The control module detects a first screen image in the first image, a second screen image in the second image, and a plurality of laser points by the first laser irradiator in the detected second screen image. And a transformation matrix for detecting a laser point by the second laser irradiator from the detected first screen image, and converting a coordinate system of the first laser irradiator into a coordinate system of a first screen and a coordinate system of the first screen. Converts the coordinate system of the second screen into a coordinate system of the second screen, converts the coordinate system of the second laser irradiator into a coordinate system of the second screen, and converts the coordinate system of the second screen into the coordinate system of the second screen. A second equation of motion is generated by using a transformation matrix that is converted into a coordinate system of the first screen, and the second equation of motion It is preferable to estimate the displacement using the second equation of motion.

The control module may estimate the displacement by applying the first and second kinematic equations to an iterative calculation method such as Newton-Labson method or Extended Kalman Filtering (EKF) method.

The control module calculates a first laser irradiation angle at which the positional difference between the laser point formed on the second screen and the second target point is minimized by the first laser irradiator, and calculates the first laser irradiation angle according to the first laser irradiation angle. The laser irradiation angle of the laser irradiator is controlled, and the second laser irradiation angle is calculated by calculating a second laser irradiation angle that minimizes the position difference between the laser point formed on the first screen and the first target point by the second laser irradiator. It is preferable to control the laser irradiation angle of the said 2nd laser irradiator accordingly.

The first laser irradiator may irradiate two laser beams onto the second screen, and the second laser irradiator may irradiate one laser beam onto the first screen.

The control module controls the center of the two laser points by the first laser irradiator to be coupled to the second target point of the second screen, and the laser point by the second laser irradiator is controlled by the first screen of the first screen. It is preferable to control so as to be in one target point.

The first target point may be the center of the first screen, and the second target point may be the center of the second screen.

Meanwhile, the structure displacement measuring method according to the present invention includes a first irradiation step of irradiating a laser beam to a second screen attached to the second structure from a first laser irradiator installed on the first structure; A second irradiation step of irradiating a laser beam to a first screen attached to the first structure from a second laser irradiator installed on the second structure; A first control step of controlling an irradiation angle of the first laser irradiator such that the laser beam irradiated from the first laser irradiator is irradiated into the second screen; A second control step of controlling an irradiation angle of the second laser irradiator such that the laser beam irradiated from the second laser irradiator is irradiated into the first screen; A first generation step of photographing the first screen to generate a first image; A second generation step of generating a second image by photographing the second screen; And estimating a relative displacement of the first structure relative to the second structure using the first image and the second image.

The structure displacement measuring method may further include correcting the displacement estimated in the estimating step by using a calibration matrix for initial offset correction.

The estimating step may include detecting a first screen image from the first image;
Detecting a second screen image in the second image; Detecting a plurality of laser points by the first laser irradiator from the detected second screen image; Detecting a laser point by the second laser irradiator on the detected first screen image; Generating a first equation of motion using a transformation matrix for converting the coordinate system of the first laser irradiator into a coordinate system of the first screen and a transformation matrix for converting the coordinate system of the first screen to the coordinate system of the second screen; Generating a second equation of motion using a transformation matrix for converting the coordinate system of the second laser irradiator into a coordinate system of the second screen and a transformation matrix for converting the coordinate system of the second screen to the coordinate system of the first screen; And estimating the displacement by using the first and second motion equations.

The estimating of the displacement may include estimating the displacement by applying the first and second equations of motion to an iterative calculation method such as Newton-Labson method or Extended Kalman Filtering (EKF) method.

The first control step may include: calculating a first laser irradiation angle that minimizes a position difference between a laser point formed on the second screen and a second target point by the first laser irradiator; And controlling the laser irradiation angle of the first laser irradiator according to the calculated first laser irradiation angle, wherein the second control step comprises: a laser formed on the first screen by the second laser irradiator Calculating a second laser irradiation angle that minimizes the positional difference between the point and the first target point; And controlling the laser irradiation angle of the second laser irradiator according to the calculated second laser irradiation angle.

The first irradiating step irradiates two laser beams from the first laser irradiator to the second screen, and the second irradiating step irradiates one laser beam from the second laser irradiator to the first screen. can do.

The first control step may include controlling the center of two laser points by the first laser irradiator to the second target point of the second screen, and the second control step may be performed by the second laser irradiator. The laser point may be controlled to be coupled to the first target point of the first screen.

On the other hand, the structure displacement control system according to the present invention, is installed on the first structure, the first laser irradiator for irradiating a laser beam to a second screen attached to the second structure; A second laser irradiator installed on the second structure and irradiating a laser beam to a first screen attached to the first structure; A first camera photographing the first screen to generate a first image; A second camera photographing the second screen to generate a second image; And a transformation matrix for detecting a plurality of laser points by the first laser irradiator in the second image, and converting a coordinate system of the first laser irradiator into a coordinate system of a first screen, and converting a coordinate system of the first screen into the second system. A first equation of motion is generated using a transformation matrix that is converted into a coordinate system of a screen, a laser point is detected by the second laser irradiator in the first image, and the coordinate system of the second laser irradiator is converted into a coordinate system of a second screen. A second kinematic equation is generated using a transform matrix for converting to and a transform matrix for converting the coordinate system of the second screen to the coordinate system of the first screen, and using the first and second motion equations, And a control module for estimating the relative displacement of the first structure relative to the second structure.

On the other hand, the structure displacement control method according to the invention, the first irradiation step of irradiating a laser beam to the second screen attached to the second structure from the first laser irradiator installed on the first structure; A second irradiation step of irradiating a laser beam to a first screen attached to the first structure from a second laser irradiator installed on the second structure; A first generation step of photographing the first screen to generate a first image; A second generation step of generating a second image by photographing the second screen; Detecting a plurality of laser points by the first laser irradiator in the second image; Generating a first equation of motion using a transformation matrix for converting the coordinate system of the first laser irradiator into a coordinate system of the first screen and a transformation matrix for converting the coordinate system of the first screen to the coordinate system of the second screen; Detecting a laser point by the second laser irradiator in the first image; Generating a second equation of motion using a transformation matrix for converting the coordinate system of the second laser irradiator into a coordinate system of the second screen and a transformation matrix for converting the coordinate system of the second screen to the coordinate system of the first screen; And estimating a relative displacement of the first structure relative to the second structure using the first and second motion equations.

The structure displacement control method may further include correcting the displacement estimated in the estimating step by using a correction matrix for initial offset correction.

On the other hand, the computer-readable recording medium according to the present invention, the first irradiation step of irradiating a laser beam from the first laser irradiator installed on the first structure to the second screen attached to the second structure; A second irradiation step of irradiating a laser beam to a first screen attached to the first structure from a second laser irradiator installed on the second structure; A first control step of controlling an irradiation angle of the first laser irradiator such that the laser beam irradiated from the first laser irradiator is irradiated into the second screen; A second control step of controlling an irradiation angle of the second laser irradiator such that the laser beam irradiated from the second laser irradiator is irradiated into the first screen; A first generation step of photographing the first screen to generate a first image; A second generation step of generating a second image by photographing the second screen; And estimating a relative displacement of the first structure relative to the second structure using the first image, the irradiation angle of the first laser irradiator , the second image and the irradiation angle of the second laser irradiator; Contains programs that can run.

On the other hand, the computer-readable recording medium according to the present invention, the first irradiation step of irradiating a laser beam from the first laser irradiator installed on the first structure to the second screen attached to the second structure; A second irradiation step of irradiating a laser beam to a first screen attached to the first structure from a second laser irradiator installed on the second structure; A first generation step of photographing the first screen to generate a first image; A second generation step of generating a second image by photographing the second screen; Detecting a plurality of laser points by the first laser irradiator in the second image; Generating a first equation of motion using a transformation matrix for converting the coordinate system of the first laser irradiator into a coordinate system of the first screen and a transformation matrix for converting the coordinate system of the first screen to the coordinate system of the second screen; Detecting a laser point by the second laser irradiator in the first image; Generating a second equation of motion using a transformation matrix for converting the coordinate system of the second laser irradiator into a coordinate system of the second screen and a transformation matrix for converting the coordinate system of the second screen to the coordinate system of the first screen; And estimating a relative displacement of the first structure relative to the second structure using the first and second motion equations. Contains programs that can run.

As described above, according to the present invention, it is possible to adjust the position of the point to the inside of the screen by controlling the direction of the laser irradiation for the structure displacement measurement, it is always possible to measure the displacement of the structure in any external situation.

In addition, more accurate structural relative displacement measurements can be made based on initial offset calibration.

In addition, according to the present invention, the distance between the screen and the camera can be shortened, so that unlike the conventional vision method, the external environment is hardly affected.

1 is a view showing the concept of a laser stance fixed structure displacement measuring system,
2 is a detailed block diagram of a laser stance fixed structure displacement measuring system;
3 shows a simulation result showing the effect of the initial offset correction,
4 is a view illustrating a concept of a laser attitude controlled structure displacement measuring system;
5 shows the laser irradiator-A in detail;
6 is a detailed block diagram of a laser attitude controlled structure displacement measuring system;
7 to 11 are views showing the results of simulating the measurement performance of the structure displacement of the controlled structure displacement measurement system shown in FIG. 4, and
12 and 13 are diagrams showing simulation results capable of comparing the controlled structure displacement measuring system and the fixed structure displacement measuring system.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

1. Laser attitude "fixed" structure displacement measuring system

1 is a view showing the concept of a laser stance fixed structure displacement measurement system. Laser attitude "Fixed" structure displacement measuring system is a system in which the direction of the laser irradiated on the screen for measuring the structure displacement is fixed. Hereinafter, for convenience of notation and description, it will be abbreviated as "fixed structure displacement measuring system".

As shown in FIG. 1, a fixed structure displacement measurement system includes a measurement module-A 110, a measurement module-B 120, and a calculation module (not shown). Measurement module-A 110 is installed in Structure-A (not shown) and measurement module-B 120 is installed in Structure-B (not shown).

Measurement module-A 110 includes a screen-A 111, a laser irradiator-A 113, and a camera-A 115, and measurement module-B 120 includes a screen-B 121, a laser irradiator. -B 123 and camera-B 125.

The laser irradiator-A 113 irradiates a pair of parallel laser beams to the screen-B 121. Accordingly, a pair of laser points are formed on the screen-B 121 attached to the structure-B. The camera-B 125 transfers the image-B generated by photographing the screen-B 121 to the calculation module.

The laser irradiator-B 123 irradiates one laser beam to the screen-A 111. Accordingly, one laser point is formed on the screen-A 111 attached to the structure-A. The camera-A 115 transfers the image-A generated by photographing the screen-A 111 to the calculation module.

The calculation module estimates the structure displacement by using the image-A received from the camera-A 115 and the image-B received from the camera-B 125. Here, "displacement structure" is a relative displacement, physically coordinate system of the screen -A (111) attached to the structure -A relative to the coordinate system of the screen Σ _B -B (121) attached to the structure -B Σ _A Means.

The structure displacement p can be expressed as [x, y, z, θ, φ, ψ]. here,

1) x is the linear displacement in the x direction from screen-B 121 to screen-A 111,

2) y is the linear displacement in the y direction from screen-B 121 to screen-A 111,

3) z is the linear displacement in the z direction from Screen-B 121 to Screen-A 111,

4) θ is the rotational displacement of the x coordinate axis of the screen-A (111) relative to the x coordinate axis of the screen-B 121,

5) φ is the rotational displacement of the y coordinate axis of the Screen-A (111) with respect to the y coordinate axis of the Screen-B 121, and

6) ψ is a rotational displacement of the z coordinate axis of Screen-A 111 with respect to the z coordinate axis of Screen-B 121.

Hereinafter, a calculation module for estimating the structure displacement p = [x, y, z, θ, φ, ψ] using the image-A and the image-B will be described in detail with reference to FIG. 2. 2 is a detailed block diagram of a computing module.

As illustrated in FIG. 2, the calculation module 200 includes an image corrector 210, a screen detector 220, a laser point detector 230, and a displacement estimator 240.

The image corrector 210 corrects and removes the distortion added to the image-A received from the camera-A 115. Similarly, for the image-B received from the camera-B 125, the image corrector 210 corrects and removes the distortion.

The screen detector 220 detects the Screen-A (111) image from the corrected image-A and detects the Screen-B (121) image from the corrected image-B by using a Corner Detection Algorithm. do.

The laser point detector 230 detects the position ^A O of the laser point projected from the detected screen-A 111 image. In addition, the laser point detector 230 detects positions ^B O and ^B Y of two laser points projected from the detected screen-B 121 image.

The displacement estimator 240 uses the positions ^A O, ^B O, and ^B Y of the laser points detected by the laser point detector 230 to displace the structure p = [x, y, z, θ, φ, ψ ] Is estimated.

2. Structure displacement estimation process

Hereinafter, the process of estimating the structure displacement p = [x, y, z, θ, φ, ψ] by the displacement estimator 240 will be described in detail.

Referring to FIG. 1, the geometric relationship between the laser point positions m = [ ^A O, ^B O, ^B Y] ^T and the structure displacement p = [x, y, z, θ, φ, ψ] ^T is shown. Kinematic Equation can be derived.

To this end, the coordinate system of the screen -B (121) Σ _B requires the coordinate system of the screen from -A (111) Σ conversion matrix for converting the coordinates to _A ^A T _B, which is expressed as Equation 1 below.

Here, T (x, y, z) is a translation matrix about the x, y, and z axes, R (x, θ) is a rotation matrix about the x-axis, and R (y, φ) is the rotation matrix about the y axis, and R (z, ψ) is the rotation matrix about the z axis.

The position ^A O of the laser point formed on the screen-A 111 may be calculated according to Equation 2 below using the transformation matrix ^A T _B.

Here, [0, L] means the x coordinate and the y coordinate of the laser irradiator-B 123 on the screen-B 121. And Z _BA means the distance from the screen-B 121 to the screen-A (111).

In the same manner as in Equation 2, ^B O and ^B Y can also be calculated. On the other hand, since the screen-A 111 and the screen-B 121 are xy planes, the z coordinate is zero. Accordingly, the z coordinates of the laser points on screen-A 111 or screen-B 121 are zero.

If the calculated positions ^A 0, ^B O and ^B Y of the laser points are respectively divided with respect to the x coordinate and the y coordinate, a motion equation such as Equation 3 below may be derived.

Here, s _θ is sinθ, c _θ is cosθ, ^A O _x is the coordinate, ^A O of ^A O x _y is the y-coordinate, ^B O _x is the x-coordinate of ^B O, ^B O _y of ^A O is y of ^B O coordinate, y ^a _x is the x coordinate of y ^a, y ^a _y represents the y coordinate of the ^a y.

By applying the Newton-Raphson method shown in Equation 4 below using the equation of motion M shown in Equation 3, displacement p = [x, y, z, θ, φ, ψ] It is possible to estimate.

Where Jp (= ∂M / ∂p) is Jacobian (Jacoby function: Jacobian) of the equation M, J ⁺ _p is pseudo-inverse of Jacobian,

Denotes laser point positions estimated by M, and m (k) denotes actual observed laser point positions.

In the above, the Newton-Lapson technique is used to estimate the displacement p, but it is only one implementation, so it is possible to use another iterative calculation technique. For example, it is also possible to estimate the displacement p = [x, y, z, θ, φ, ψ] by applying the motion equation M shown in Equation 3 to the Extended Kalman Filtering (EKF) technique.

3. Initial Offset correction( Calibration of initial offset )

Hereinafter, in the fixed structure displacement measuring system described above and the controlled structure displacement measuring system described below, a method of correcting offset due to initial displacement will be described in detail.

For the initial offset calibration, we first calculate the initial displacement p ₀ = [x ₀ , y ₀ , z ₀ , θ ₀ , φ ₀ , ψ ₀ ] ^T and use it to generate a calibration matrix. Matrix ^A T _cal is shown in Equation 5 below.

Where T (x, y, z) is a translation matrix for the X, Y, and Z axes, R (x, θ) is a rotation matrix for the X axis, and R (y, [theta] is the rotation matrix about the Y axis, and R (z, ψ) is the rotation matrix about the z axis.

Thereafter, as shown in Equation 6 below, the inverse of the calibration matrix ^A T _cal is multiplied by the transformation matrix ^A T _B to obtain a corrected transformation matrix T _new .

Using the corrected transformation matrix T _new, we can obtain the displacement p _new whose initial offset is corrected, and the corrected displacement p _new = [x ', y', z ', θ', φ ', ψ'] As shown in Equation 7, it can be expressed using the elements of T _new .

3 shows a simulation result showing the effect of the initial offset correction. In FIG. 3, the solid line is the displacement estimation result when the initial offset is corrected, and the dotted line is the displacement estimation result when the initial offset is not corrected.

As shown in FIG. 3, it can be seen that the solid line starts from 0, due to the correction of the initial offset.

4. Laser attitude "controlled" structure displacement measuring system

In the fixed structure displacement measuring system described above, laser points are required to be present in the screen as a prerequisite for estimating structure displacement. However, due to environmental impacts, it may be difficult for laser points to be irradiated into the screen, which needs to be compensated for.

Hereinafter, a structure displacement measuring system capable of adjusting point positions by controlling the irradiation direction of lasers by 2-DOF driving is proposed.

4 is a view illustrating a concept of a laser attitude controlled structure displacement measuring system. Laser attitude "Controlled" structure displacement measuring system is a system that can control the direction of the laser irradiated to the screen to measure the structure displacement, and ultimately adjust the position of the laser point on the screen. For convenience, abbreviated as "controlled structure displacement measuring system".

As shown in FIG. 4, the controlled structure displacement measurement system includes a measurement module-A 410, a measurement module-B 420, and a control module (not shown). Measurement module-A 410 is installed in Structure-A (not shown) and measurement module-B 420 is installed in Structure-B (not shown).

Measurement module-A 410 has a screen-A 411, a laser irradiator-A 413 and a camera-A 415, and measurement module-B 420 has a screen-B 421, a laser irradiator A B-423 and a camera-B 425.

The laser irradiator-A 413 irradiates a pair of parallel laser beams. The laser irradiator-A 413 is rotatable about the x and z axes. The left side of FIG. 5 shows a view of the laser irradiator-A 413 as viewed from above, and the right side of FIG. 5 shows a view of the laser irradiator-A 413 as viewed from the right.

The laser irradiator-A 413 is drive controlled by the control module. Specifically, the control module is arranged such that the center of the pair of laser points by the laser irradiator-A 413 is centered on the target point-B in the screen-B 421 attached to the structure-B. Control the laser irradiation angle.

The camera-B 425 transfers the image-B generated by photographing the screen-B 421 to the calculation module.

The laser irradiator-B 423 irradiates one laser beam. The laser irradiator-B 423 is also rotatable about the x and z axes.

The laser irradiator-B 423 is also drive controlled by the control module. Specifically, the control module is configured such that the laser irradiation angle of the laser irradiator-B 423 is such that the laser point by the laser irradiator-B 423 is coupled to the target point-A in the screen-B 421 attached to the structure-B. To control.

The camera-A 415 transfers the image-A generated by photographing the screen-A 411 to the calculation module.

The control module controls the laser irradiation angles of the laser irradiators 413 and 423 by using 'image-A received from the camera-A 415' and 'image-B received from the camera-B 425'. And estimate the displacement of the structure.

Hereinafter, a control module that controls the laser irradiation angle using the image-A and the image-B and estimates the structure displacement p = [x, y, z, θ, φ, ψ] in detail with reference to FIG. 6. Explain. 6 is a detailed block diagram of the control module.

As shown in FIG. 6, the control module 600 includes an image corrector 610, a screen detector 620, a laser point detector 630, a displacement estimator 640, a point position difference calculator 650, A laser irradiation angle calculator 660, a laser irradiation angle controller 670, a transformation matrix generator 680, and a calibration matrix generator 690 are provided.

The image corrector 610, the screen detector 620, and the laser point detector 630 may be implemented in the same manner as the image corrector 210, the screen detector 220, and the laser point detector 230 illustrated in FIG. 2. Therefore, detailed description thereof will be omitted.

The point position difference calculator 650 calculates the position difference between the center of the pair of laser points by the laser irradiator-A 413 and the target point-B. In addition, the point position difference calculator 650 calculates a position difference between the laser point and the target point-A by the laser irradiator-B 423.

Here, target point-A is the center of screen-A, and target point-B is the center of screen-B.

The laser irradiation angle calculation unit 660 is a laser irradiation of the laser irradiator-A (413) to minimize the positional difference between the 'center of a pair of laser points by the laser irradiator-A (413)' and 'target point-B' Calculate the angle. In addition, the laser irradiation angle calculator 660 calculates the laser irradiation angle of the laser irradiator-B 423 which minimizes the positional difference between the 'laser point by the laser irradiator-B 423' and the 'target point-A'. do.

The laser irradiation angle controller 670 controls the laser irradiator-A 413 and the laser irradiator-B 423, respectively, so that the laser irradiation is performed according to the laser irradiation angle calculated by the laser irradiation angle calculator 660.

A transformation matrix generating unit 680, a laser irradiator -A (413) coordinate system Σ _A laser irradiator -B (423) generates a _"to the coordinate system of the screen -A Σ _A transformation matrix ^A T _A to convert _', and for for the coordinate system Σ _B generates _"the transformation matrix ^B T _B to convert to the coordinate system of the screen Σ _B -B _'.

Hereinafter, a process of generating the transformation matrix ^A T _A _′ and the transformation matrix ^B T _B _′ by the transformation matrix generator 680 will be described in detail.

Equation 8 below including the laser irradiation angles of the laser irradiator-A 413 can be assumed.

Where ^B t is the center of screen-B 421 to target point-B. ^B t _x is the x-coordinate of ^B t, ^B t _y is the y coordinate of ^B t. Θ _A and ψ _A mean laser irradiation angles such that the center of the laser points by the laser irradiator-A 413 is located at the center of the screen-B 421 which is the target point-B.

In addition, [0, 0] means the x coordinate and the y coordinate of the laser irradiator-A 413 in the screen-A 411, and Z _A'B is the laser irradiator-A 413 and the screen-B 421. ) Is the distance between.

Since the z coordinate is zero in the coordinate system Σ _B of the screen-B 421, the z coordinate of the target point ^B t is zero. Meanwhile, in Equation 8, the transformation matrix ^B T _A may be obtained by calculating an inverse of ^A T _B shown in Equation 1.

Meanwhile, similarly to Equation 8, the following Equation 9 including the laser irradiation angles of the laser irradiator-B 423 may be assumed.

Where ^A t is the center of screen-A 411 to target point-A. ^A t _x t ^A is the x-coordinate, _y is the y-coordinate of ^A t ^A t. Θ _B and ψ _B mean laser irradiation angles such that the laser point irradiated from the laser irradiator-B 423 is located at the center of the screen-A 411 which is the target point-A.

In addition, [0, -L] means the x coordinate and the y coordinate of the laser irradiator-B 423 in the screen-B 421, and Z _B'A denotes the laser irradiator-B 423 and the screen-A ( 411) distance.

Since the z coordinate is zero in the coordinate system Σ _A of the screen-A 411, the z coordinate of the target point ^A t is zero.

When the above Equations 8 and 9 are combined into one, the relationship between the target points and the laser irradiation angles may be expressed by Equation 10.

here,

to be. And, θ is a rotation angle in a coordinate system Σ _AB to _B of the screen -A (411) screen coordinate system Σ -B (421) at the time of _A in the x-axis, θ _B is to the x axis screen -B It is the rotation angle from the coordinate system (Sigma) _B of (421) to the coordinate system (Sigma) _{B '} of the laser irradiator-B (423).

Meanwhile,

Similarly,

ego,

Is,

to be.

By applying the Newton-Rabson technique or EKF using Equation M _r shown in Equation 10, it is possible to estimate the laser irradiation angles that can locate the laser point or the center of the laser points at the target point.

Coordinates of laser irradiation -A (413) Σ _{A 'screen} -A (411) Σ coordinate system transformation matrix to convert _A ^A T _A of _the' possible is calculated using the θ ψ _A and _A, equation (11) below, and same.

Further, in the same way as above, the coordinate system of the applicator -B (423) using the θ and ψ _B _B. Σ _B to calculate the _"a transformation matrix ^B T _B to convert to the coordinate system of the laser _B Σ screen -B (421) _' Of course you can.

Meanwhile, the calibration matrix generator 690 generates a calibration matrix ^A T _cal for initial offset calibration. The calibration matrix generator 690 generates a calibration matrix according to the above-described "3. initial offset calibration".

The displacement estimator 640 may include 1) positions of three laser points detected by the laser point detector 630, and 2) transformation matrices ^A T _A _′ , ^B T generated by the transformation matrix generator 680. _{B ′} 3) The structure displacement is estimated using the calibration matrix ^A T _cal generated by the calibration matrix generator 690.

Hereinafter, a method of estimating structure displacement by the displacement estimating unit 640 will be described in detail.

First, using the positions of the three laser points detected by the laser point detector 630 and the transformation matrices ^A T _A _′ and ^B T _B _′ generated by the transformation matrix generator 680, the displacement p = The equation of motion including [x, y, z, θ, φ, ψ] is derived.

Specifically, the position ^A O _B _′ of the laser point irradiated from the laser irradiator-B 423 to the screen-A 411 is expressed by Equation 12 below.

Further, the positions ^B O _A _′ and ^B Y _A _′ of the laser points irradiated from the laser irradiator-A 413 to the screen-B 421 are expressed by Equation 13 below.

In Equations 12 and 13, the z coordinates of ^A O _B _′ , ^B O _A _′ and ^B Y _A _′ are zero.

Integrating equations (12) and (13) into one, a motion equation including the displacement p = [x, y, z, θ, φ, ψ] for the controlled structure displacement measurement system is derived as shown in equation (14) below. .

Subsequently, the displacement estimator 640 repeatedly applies the Newton-Rapson method shown in Equation 4 using the equation M _vs. in Equation 14, whereby displacement p = [x, y, z, θ, φ , ψ] is estimated. In addition, the displacement estimating unit 640 may estimate the displacement p = [x, y, z, θ, φ, ψ] by applying the motion equation M _vs shown in Equation 14 to the EKF technique.

The displacement estimator 640 obtains the corrected transform matrix T _new by substituting the correction matrix ^A T _cal generated by the correction matrix generator 690 into Equation 6 described above, and corrects the corrected transform matrix T _new. By using Equation 7, the displacement p _new = [x ', y', z ', θ', φ ', ψ'] obtained by correcting the initial offset is obtained.

5. Simulation Results

7 to 11 are diagrams showing the results of simulating the measurement performance of the structure displacement of the controlled structure displacement measurement system shown in FIG.

7 to 11, the solid line represents the actual structure displacement, the long dotted line represents the estimated structure displacement when the initial offset calibration is performed, and the short dotted line represents the estimated structure displacement when the initial offset calibration is not performed. Indicates. Meanwhile, the distance between Structure-A and Structure-B was assumed to be 100m.

According to the simulation result using the Newton-Rapson method shown in FIG. 7, it can be seen that the estimated structure displacement converges to the actual structure displacement in a relatively short time when the initial offset correction is performed.

In addition, FIG. 8 shows a simulation result of applying the Newton-Rabson technique when noise is added artificially to the detected laser point positions. In this case, the results are relatively satisfactory.

On the other hand, Figure 9 shows the results of estimating the structure displacement by applying the EKF technique in the same conditions as in Figure 8, it can be seen that the excellent performance even when the EKF technique is applied.

In addition, FIG. 10 shows a simulation result of applying the Newton-Rabson technique when the x coordinate of the structure displacement is artificially changed. In this case, it can be seen that the convergence to the actual structure displacement is changed well.

On the other hand, Figure 11 shows the results of estimating the structure displacement by applying the EKF technique under the same conditions as in Figure 10, it can be seen that the excellent performance even when the EKF technique is applied.

The upper part of FIG. 12 shows the position coordinates of the radar points in the screen when the Newton-Lapson technique is applied in the controlled structure displacement measuring system, and the lower part of FIG. The position coordinates of the point are shown. 12 it can be seen that the displacement of the laser point is more stable in the controlled structure displacement measurement system.

In addition, FIG. 13 illustrates a case in which the EKF technique is applied under the same conditions as in FIG. 12, and the same result as in FIG. 12 can be obtained.

Meanwhile, the structure-A and the structure-B in which the measurement module-A and the measurement module-B mentioned in the above embodiments are installed may be separate structures as well as a single structure.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

110, 410: Measurement module-A 111, 411: Screen-A
113, 413: Laser irradiator-A 115, 415: Camera-A
120, 420: Measurement module-B 121, 421: Screen-B
123, 423: laser irradiator-B 125, 425: camera-B
200: operation module 210: image correction unit
220: screen detection unit 230: laser point detection unit
240: displacement estimation unit 600: control module
610: image correction unit 620: screen detection unit
630: laser point detection unit 640: displacement estimation unit
650: point position difference calculation unit 660: laser irradiation angle calculation unit
670: laser irradiation angle control unit 680: transformation matrix generation unit
690: calibration matrix generator

Claims

A first laser irradiator installed on the first structure and irradiating a laser beam to a second screen attached to the second structure;
A second laser irradiator installed on the second structure and irradiating a laser beam to a first screen attached to the first structure;
A first camera photographing the first screen to generate a first image;
A second camera photographing the second screen to generate a second image; And
The irradiation angle of the first laser irradiator is controlled so that the laser beam irradiated from the first laser irradiator is irradiated inside the second screen, and the laser beam irradiated from the second laser irradiator is irradiated inside the first screen. And a control module for controlling an irradiation angle of the second laser irradiator and estimating a relative displacement of the first structure with respect to the second structure using the first image and the second image. Structure displacement measuring system.

The method of claim 1,
The control module,
And correcting the estimated displacement using a calibration matrix for initial offset calibration.

The method of claim 1,
The control module,
Detecting a first screen image in the first image, detecting a second screen image in the second image, detecting a plurality of laser points by the first laser irradiator in the detected second screen image,
Detecting a laser point by the second laser irradiator on the detected first screen image,
Generating a first equation of motion using a transformation matrix for converting the coordinate system of the first laser irradiator into a coordinate system of the first screen and a transformation matrix for converting the coordinate system of the first screen to the coordinate system of the second screen,
Generating a second equation of motion using a transformation matrix for converting the coordinate system of the second laser irradiator into a coordinate system of the second screen and a transformation matrix for converting the coordinate system of the second screen to the coordinate system of the first screen,
And using the first and second motion equations to estimate the displacement.

The method of claim 3, wherein
The control module,
And applying the first and second kinematic equations to an iterative calculation technique of one of Newton-Rapson and Extended Kalman Filtering (EKF) techniques to estimate the displacement.

The method of claim 1,
The control module,
The first laser irradiation angle is calculated by the first laser irradiator to minimize the position difference between the laser point formed on the second screen and the second target point, the laser irradiation of the first laser irradiator according to the first laser irradiation angle Control the angle,
The second laser irradiation angle is calculated by the second laser irradiator to minimize the position difference between the laser point formed on the first screen and the first target point, and the laser irradiation of the second laser irradiator according to the second laser irradiation angle Structure displacement measuring system, characterized in that for controlling the angle.

The method of claim 1,
The first laser irradiator,
Irradiate two laser beams onto the second screen,
The second laser irradiator,
And irradiating one laser beam onto the first screen.

The method according to claim 6,
The control module,
Control the center of the two laser points by the first laser irradiator to be joined to the second target point of the second screen,
And control the laser point by the second laser irradiator to the first target point of the first screen.

8. The method of claim 7,
The first target point is the center of the first screen,
And the second target point is the center of the second screen.

A first irradiation step of irradiating a laser beam from a first laser irradiator installed on the first structure to a second screen attached to the second structure;
A second irradiation step of irradiating a laser beam to a first screen attached to the first structure from a second laser irradiator installed on the second structure;
A first control step of controlling an irradiation angle of the first laser irradiator such that the laser beam irradiated from the first laser irradiator is irradiated into the second screen;
A second control step of controlling an irradiation angle of the second laser irradiator such that the laser beam irradiated from the second laser irradiator is irradiated into the first screen;
A first generation step of photographing the first screen to generate a first image;
A second generation step of generating a second image by photographing the second screen; And
Estimating a relative displacement of the first structure with respect to the second structure using the first image and the second image.

The method of claim 9,
And correcting the displacement estimated in the estimating step by using a calibration matrix for initial offset correction.

The method of claim 9,
The estimating step,
Detecting a first screen image in the first image;
Detecting a second screen image in the second image;
Detecting a plurality of laser points by the first laser irradiator from the detected second screen image;
Detecting a laser point by the second laser irradiator on the detected first screen image;
Generating a first equation of motion using a transformation matrix for converting the coordinate system of the first laser irradiator into a coordinate system of the first screen and a transformation matrix for converting the coordinate system of the first screen to the coordinate system of the second screen;
Generating a second equation of motion using a transformation matrix for converting the coordinate system of the second laser irradiator into a coordinate system of the second screen and a transformation matrix for converting the coordinate system of the second screen to the coordinate system of the first screen; And
Estimating the displacement by using the first equation and the second equation of motion.

12. The method of claim 11,
Estimating the displacement,
And applying the first and second equations of motion to an iterative calculation method of any one of Newton-Labson and Extended Kalman Filtering (EKF) techniques to estimate the displacement.

The method of claim 9,
The first control step,
Calculating a first laser irradiation angle at which a position difference between a laser point formed on the second screen and a second target point is minimized by the first laser irradiator; And
Controlling the laser irradiation angle of the first laser irradiator according to the calculated first laser irradiation angle;
The second control step,
Calculating a second laser irradiation angle by which the position difference between the laser point formed on the first screen and the first target point is minimized by the second laser irradiator; And
And controlling the laser irradiation angle of the second laser irradiator in accordance with the calculated second laser irradiation angle.

The method of claim 9,
The first irradiation step,
Irradiating two laser beams from the first laser irradiator to the second screen,
The second irradiation step,
And irradiating one laser beam from the second laser irradiator onto the first screen.

The method of claim 14,
The first control step,
Control the center of the two laser points by the first laser irradiator to be joined to the second target point of the second screen,
The second control step,
And controlling the laser point by the second laser irradiator to the first target point of the first screen.

16. The method of claim 15,
The first target point is the center of the first screen,
And the second target point is the center of the second screen.

A first laser irradiator installed on the first structure and irradiating a laser beam to a second screen attached to the second structure;
A second laser irradiator installed on the second structure and irradiating a laser beam to a first screen attached to the first structure;
A first camera photographing the first screen to generate a first image;
A second camera photographing the second screen to generate a second image; And
A transformation matrix for detecting a plurality of laser points by the first laser irradiator in the second image, and converting a coordinate system of the first laser irradiator into a coordinate system of a first screen, and converting a coordinate system of the first screen to the second screen A first equation of motion is generated using a transformation matrix that transforms the coordinate system into a coordinate system, a laser point is detected by the second laser irradiator in the first image, and the coordinate system of the second laser irradiator is used as the coordinate system of the second screen. A second motion equation is generated using a transform matrix for transforming and a transform matrix for transforming a coordinate system of the second screen into a coordinate system of the first screen. The second motion equation is generated using the first motion equation and the second motion equation. And a control module for estimating the relative displacement of the first structure relative to the second structure. Above measurement system.

18. The method of claim 17,
The control module,
And correcting the estimated displacement using a calibration matrix for initial offset calibration.

A first irradiation step of irradiating a laser beam from a first laser irradiator installed on the first structure to a second screen attached to the second structure;
A second irradiation step of irradiating a laser beam to a first screen attached to the first structure from a second laser irradiator installed on the second structure;
A first generation step of photographing the first screen to generate a first image;
A second generation step of generating a second image by photographing the second screen;
Detecting a plurality of laser points by the first laser irradiator in the second image;
Generating a first equation of motion using a transformation matrix for converting the coordinate system of the first laser irradiator into a coordinate system of the first screen and a transformation matrix for converting the coordinate system of the first screen to the coordinate system of the second screen;
Detecting a laser point by the second laser irradiator in the first image;
Generating a second equation of motion using a transformation matrix for converting the coordinate system of the second laser irradiator into a coordinate system of the second screen and a transformation matrix for converting the coordinate system of the second screen to the coordinate system of the first screen; And
Estimating a relative displacement of the first structure relative to the second structure using the first and second motion equations.

20. The method of claim 19,
And correcting the displacement estimated in the estimating step by using a calibration matrix for initial offset correction.

A first irradiation step of irradiating a laser beam from a first laser irradiator installed on the first structure to a second screen attached to the second structure;
A second irradiation step of irradiating a laser beam to a first screen attached to the first structure from a second laser irradiator installed on the second structure;
A first control step of controlling an irradiation angle of the first laser irradiator such that the laser beam irradiated from the first laser irradiator is irradiated into the second screen;
A second control step of controlling an irradiation angle of the second laser irradiator such that the laser beam irradiated from the second laser irradiator is irradiated into the first screen;
A first generation step of photographing the first screen to generate a first image;
A second generation step of generating a second image by photographing the second screen; And
Estimating a relative displacement of the first structure relative to the second structure by using the first image and the second image; and a computer-readable recording medium containing a program capable of performing the same.

A first irradiation step of irradiating a laser beam from a first laser irradiator installed on the first structure to a second screen attached to the second structure;
A second irradiation step of irradiating a laser beam to a first screen attached to the first structure from a second laser irradiator installed on the second structure;
A first generation step of photographing the first screen to generate a first image;
A second generation step of generating a second image by photographing the second screen;
Detecting a plurality of laser points by the first laser irradiator in the second image;
Generating a first equation of motion using a transformation matrix for converting the coordinate system of the first laser irradiator into a coordinate system of the first screen and a transformation matrix for converting the coordinate system of the first screen to the coordinate system of the second screen;
Detecting a laser point by the second laser irradiator in the first image;
Generating a second equation of motion using a transformation matrix for converting the coordinate system of the second laser irradiator into a coordinate system of the second screen and a transformation matrix for converting the coordinate system of the second screen to the coordinate system of the first screen; And
Estimating a relative displacement of the first structure with respect to the second structure using the first and second motion equations.