Laser diameter measuring method and diameter measuring instrument

Abstract

The invention relates to a laser diameter measuring method and a diameter measuring instrument, and the method comprises the following steps: enabling a laser range finder to sequentially aim at any three points on the section of the pipe wall of a to-be-measured pipe body, and measuring the distance between the laser range finder and the points in the process, recording the rotating angle of the laser range finder when the laser range finder is switched from aiming at one point to the next point to obtain a group of distance and rotating angle data; calculating the mutual distances of the three points according to the distance and rotation angle data; and calculating the diameter of the section of the pipe wall according to the mutual distances of the three points and a circumcircle diameter formula. According to the invention, the diameter of the pipe body is measured by using laser, and the device can be applied to some operation scenes (such as high-altitude measurement and underground measurement) in which direct measurement cannot be carried out.

Description

Technical Field

[0001] The invention relates to the technical field of pipe diameter measurement, in particular to a laser diameter measurement method and a diameter measuring instrument. Background Art

[0002] In the pipe diameter measurement operation, it is difficult to accurately measure the pipes buried at a greater depth by using a flower rod and visual inspection. At present, plastic pipes, cast iron pipes, steel pipes and other pipes have been used in drainage pipes. Different from the standard concrete pipes, their diameter sizes are often non-standard, so when measuring their pipe diameters, it is necessary to ensure the measurement accuracy.

[0003] The pipe diameter measurement data has a direct impact on the subsequent engineering repair or renovation plan. If the measurement data is inaccurate or has errors, it will affect the subsequent implementation. Therefore, in order to ensure the feasibility of the engineering plan, after the rough measurement on the ground, the surveyors are often required to go down the well to conduct accurate measurements. However, due to the limited space underground and the fact that the sewage pipe is in operation, the downhole measurement has a greater operational risk.

[0004] The commonly used diameter gauges on the market require the device to be measured to be placed in the middle of the pipe body for measurement. The measurement range is small, and the maximum effective measurement range is within 0.2 meters. It is not suitable for buried pipe diameter measurement. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a laser diameter measurement method and a diameter measuring instrument in view of the above shortcomings. The present invention uses laser to measure the diameter of the pipe body, which can be applied to some operating scenarios where direct measurement cannot be performed (such as high-altitude measurement, underground measurement).

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: A laser diameter measurement method comprises the following steps: A laser rangefinder is sequentially aimed at any three points on the cross section of the pipe wall of the pipe body to be measured, and in this process, the distance between the laser rangefinder and the points is measured, and the rotation angle of the laser rangefinder when switching from aiming at one point to the next point is recorded to obtain a set of distance and rotation angle data; According to the distance and rotation angle data, calculate the mutual distance of the three points; The diameter of the pipe wall section is calculated based on the mutual distances of the three points and the formula for the diameter of the circumscribed circle.

[0007] Further, the step of calculating the mutual distance between any two points of the three points according to the distance and rotation angle data includes: When the laser rangefinder is aimed at one of the points, a spatial coordinate system consisting of three axes, X, Y, and Z, is established, the position of the laser rangefinder is recorded as the origin Q, and the ray of the laser rangefinder is located on the QX axis; When the laser rangefinder aims at the next point, the angle of rotation around the QZ axis is recorded as , and its rotation angle relative to the XQY plane is recorded as ; According to the angle and angle , calculate the angle between the two points ; According to the distance and angle between the laser rangefinder and the two points , use the law of cosines to calculate the mutual distance between two points.

[0008] Furthermore, according to the angle and angle , calculate the angle between the two points The steps include: Convert laser rangefinder rays to unit vectors ,set up ; Get the rotation angle of the laser rangefinder's ray around the QZ axis The rotation matrix : ; Will and Multiply them together to get the direction vector : ; Get the rotation angle of the laser rangefinder's ray relative to the XQZ plane The rotation matrix : ; Will and Multiply them together to get the direction vector : ; and Angle Using the dot product formula we get: ; Dot Product ; because is the unit vector Rotated, so: .

[0009] Furthermore, according to the distance between the laser rangefinder and the two points and the angle , the formula for calculating the mutual distance between two points using the cosine theorem is: ; in, is the distance between two points, and are the distances between the laser rangefinder and the two points respectively.

[0010] Furthermore, the step of calculating the diameter of the pipe wall section according to the mutual distances of the three points and the circumscribed circle diameter formula includes: Note that any three points on the cross section of the tube wall to be tested are point A, point B and point C. According to Heron's formula, calculate the area of ​​the triangle formed by the three points. : ; Among them, p is the semi-perimeter of the triangle, a, b and c are the distances between the three points, that is, AB=a, BC=b, CA=c; the semi-perimeter p of the triangle is: ; Substituting equation (2) into equation (1), the area of ​​the triangle is for: ; Lead out from point C and pass through The auxiliary line CD of the origin O of the circumscribed circle of The intersection of the circumscribed circles of Connect DA. Since ∠CBA=∠CDA, and ∠CAD is a right angle, we get: ; Substituting equation (5) into equation (4), we get The diameter d of the circumscribed circle is: .

[0011] A laser diameter measuring instrument comprises a distance measuring module, an angle adjustment module and a control unit; The distance measurement module is used to measure the distance to the target point; The distance measuring module is arranged on the angle adjusting module, and the angle adjusting module is used to drive the distance measuring module to rotate in two mutually perpendicular planes; The control unit is used to receive and store the distance data measured by the distance measuring module and the rotation angle data of the angle adjustment module. The control unit is also used to calculate the diameter of the tube wall section of the tube body to be measured based on the distance data and the rotation angle data.

[0012] Furthermore, it also includes a bracket module, and the angle adjustment module is arranged on the bracket module.

[0013] After adopting the above technical solution, the present invention has the following advantages compared with the prior art: The present invention does not require surveyors to go down the well for measurement. It only requires the caliper to be aimed at any three points on the pipe wall cross-section of the pipe body to be measured. The mutual distances of the three points can be calculated based on the distances between the caliper and the three points, as well as the angle of rotation during the measurement process. Then, the diameter of the pipe body to be measured can be calculated based on the direct formula for the circumscribed circle.

[0014] The present invention is described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the laser diameter measuring instrument of the present invention; Figure 2 It is a schematic diagram of the local structure of the laser diameter measuring instrument of the present invention; Figure 3 This is a diagram showing the use status of the laser diameter measuring instrument of the present invention; Figure 4 A schematic diagram of an arbitrary triangle ABC and its circumscribed circle.

[0016] In the accompanying drawings, the components represented by the reference numerals are listed as follows: 1. Distance measurement module; 2. Angle adjustment module; 21. Vertical bracket; 22. Vertical rotation motor; 23. Horizontal rotation base; 24. Connecting base plate; 25. Horizontal rotation motor; 26. Level; 3. Control unit; 4. Bracket module. DETAILED DESCRIPTION

[0017] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0018] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", "clockwise" and "counterclockwise" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0019] Embodiment 1: A laser diameter measurement method specifically comprises the following steps: (1) Collect distance and rotation angle data: Use a laser rangefinder to aim at any three points on the cross-section of the pipe wall of the pipe to be measured in turn, and record these three points as point A, point B and point C. In this process, measure the distances between the laser rangefinder and point A, point B and point C respectively, and record the angle of rotation of the laser rangefinder when it switches from aiming at point A to aiming at point B, the angle of rotation of the laser rangefinder when it switches from aiming at point B to aiming at point C, and the angle of rotation of the laser rangefinder when it switches from aiming at point C to aiming at point A.

[0020] (2) Calculate the distance between point A and point B, the distance between point B and point C, and the distance between point C and point A: The following example shows how to calculate the distance between two points by calculating the distance between point A and point B. (2.1) Set up an aperture coordinate system consisting of the three axes X, Y, and Z, and the position of the laser rangefinder is the origin Q. When the laser rangefinder is aimed at point A, convert the ray of the laser rangefinder into a space vector , and assume is a unit vector; (2.2) When the laser rangefinder switches from aiming at point A to aiming at point B, the angle of rotation around the QZ axis is recorded as , and its rotation angle relative to the XQY plane is recorded as ; Get the rotation angle of the laser rangefinder around the QZ axis The rotation matrix : ; Vector With the rotation matrix Multiply them together to get the new direction vector : ; Get the rotation angle of the laser rangefinder relative to the XQY plane The rotation matrix : ; Vector With the rotation matrix Multiply them together to get the new direction vector : ; vector The direction vector to the X axis The angle ∠AQB is obtained by the dot product formula: ; Dot Product ; Since the vector is the unit vector Rotated and is a unit vector ,therefore: ;therefore: ; (2.3) Finally, the distance between point A and point B can be calculated using the law of cosines: ; Among them, AB is the distance between point A and point B, QA is the distance between the laser rangefinder and point A, and QB is the distance between the laser rangefinder and point B; Repeat steps (2.1) to (2.3) to obtain the distance between point B and point C and the distance between point C and point A.

[0021] (3) Calculation The diameter d of the circumscribed circle is the diameter d of the pipe wall section of the pipe to be tested: Calculate the area of ​​the triangle formed by points A, B, and C using Heron's formula : ; Among them, a is the distance between point A and point B, b is the distance between point B and point C, c is the distance between point C and point A, and p is the semi-perimeter of the triangle; Among them, the semi-perimeter p of the triangle is: ; Substitute (Formula 1) into (Formula 2): ; From the area formula of a triangle: ; like Figure 4 As shown, draw an auxiliary line CD from point C through the origin O of the circumscribed circle. D is the intersection of the auxiliary line CD and the circumscribed circle, and connect DA. From the equal included angles of the same chords in the circle, we know that ∠CBA=∠CDA. Since the triangle whose hypotenuse passes through the center of the circle is a right triangle, ∠CAD is a right angle. Therefore: ; Among them, AC and c are the distances between points A and C, CD is the distance between points C and D, and d is The diameter of the circumscribed circle; Substituting (Equation 5) into (Equation 4), we can get the diameter d of the circumscribed circle: .

[0022] Where d is The diameter of the circumscribed circle is the diameter of the tube wall section of the tube to be tested.

[0023] Embodiment 2: In order to implement the measurement method of the first embodiment, this embodiment provides a laser diameter measuring instrument.

[0024] In this embodiment, the laser diameter measuring instrument is mainly composed of a distance measuring module 1, an angle adjustment module 2, a control unit 3 and a bracket module 4; like Figure 1 and Figure 2 As shown, in this embodiment, the distance measuring module 1 includes a laser, a sensor and an optical observer. The distance measuring module 1 is used to measure the distance to the target point. It can be understood that the distance measuring module 1 is the laser rangefinder in the first embodiment.

[0025] The angle adjustment module 2 includes a vertical bracket 21, a vertical rotation motor 22, a horizontal rotation base 23, a connecting base plate 24 and a horizontal rotation motor 25. The distance measuring module 1 is rotatably arranged on the vertical bracket 21, the vertical rotation motor 22 is arranged on the vertical bracket 21, and the output end of the vertical rotation motor 22 is connected to the distance measuring module 1. The vertical rotation motor 22 is used to drive the distance measuring module 1 to rotate in a vertical plane. The vertical bracket 21 is arranged on the horizontal rotation base 23, the horizontal rotation base 23 is rotatably arranged on the connecting base plate 24, the horizontal rotation motor 25 is arranged on the connecting base plate 24, and the output end of the horizontal rotation motor 25 is connected to the horizontal rotation base 23. The horizontal rotation motor 25 is used to drive the horizontal rotation base 23 to rotate in a horizontal plane. A level meter 26 is also provided on the horizontal rotating base 23 , and the level meter 26 is used to detect the inclination angle of the horizontal rotating base 23 relative to the horizontal position.

[0026] The control unit 3 is connected with the laser, the sensor, the optical observation instrument, the vertical rotating motor 22, the horizontal rotating motor 25 and the level 26. The control unit 3 is used to receive the measurement data of the laser, the sensor, the optical observation instrument and the level 26, as well as the rotation angle data of the vertical rotating motor 22 and the horizontal rotating motor 25, and is also used to calculate the diameter of the pipe wall section of the pipe body to be measured according to these data; Furthermore, a display device is included, and the control unit 3 is connected to the display device, and the control unit 3 can display the received measurement data and rotation angle data and the calculated diameter through the display device; Furthermore, the control unit 3 may also add a communication module to realize wireless or wired communication through the communication module, and transmit the data obtained by the control unit and the calculated diameter data to the external terminal, or realize the remote control measurement function of the remote control terminal through the communication module.

[0027] The support module 4 is a tripod.

[0028] When using, Figure 3 As shown, the caliper is placed near the wellhead through the support module 4, and the support module 4 is adjusted in conjunction with the spirit level 26 to make the horizontal rotating base 23 in a horizontal state, so that the distance measuring module 1 is aligned with any three points on the pipe wall section of the pipe body to be measured, and the control unit 3 records the distance between the distance measuring module 1 and the three points and the rotation angle during the operation, and calculates the diameter of the pipe wall section of the pipe body to be measured based on the distance and rotation angle data.

[0029] The above is an example of the best implementation of the present invention, and the parts not described in detail are common knowledge of ordinary technicians in the field. The protection scope of the present invention shall be based on the content of the claims, and any equivalent transformation based on the technical enlightenment of the present invention is also within the protection scope of the present invention.

Claims

1. A laser diameter measurement method, characterized in that: The following steps are involved: A laser rangefinder is sequentially aimed at any three points on the cross section of the pipe wall of the pipe body to be measured, and in this process, the distance between the laser rangefinder and the points is measured, and the rotation angle of the laser rangefinder when switching from aiming at one point to the next point is recorded to obtain a set of distance and rotation angle data; According to the distance and rotation angle data, calculate the mutual distance of the three points; The diameter of the pipe wall section is calculated based on the mutual distances of the three points and the formula for the diameter of the circumscribed circle.

2. The laser diameter measurement method according to claim 1, characterized in that: The steps of calculating the mutual distance between any two points among the three points according to the distance and rotation angle data include: When the laser rangefinder is aimed at one of the points, a spatial coordinate system consisting of three axes, X, Y, and Z, is established, the position of the laser rangefinder is recorded as the origin Q, and the ray of the laser rangefinder is located on the QX axis; When the laser rangefinder aims at the next point, the angle of rotation around the QZ axis is recorded as , and its rotation angle relative to the XQY plane is recorded as ; According to the angle and angle , calculate the angle between the two points ; According to the distance and angle between the laser rangefinder and the two points , use the law of cosines to calculate the mutual distance between two points.

3. The laser diameter measurement method according to claim 2, characterized in that: According to the angle and angle , calculate the angle between the two points The steps include: Convert laser rangefinder rays to unit vectors ,set up ; Get the rotation matrix of the laser rangefinder's ray rotation angle around the QZ axis : ; Will and Multiply them together to get the direction vector : ; Get the rotation angle of the laser rangefinder's ray relative to the XQZ plane The rotation matrix : ; Will and Multiply them together to get the direction vector : ; and Angle Using the dot product formula we get: ; Dot Product ; because is the unit vector Rotated, so: .

4. The laser diameter measurement method according to claim 2, characterized in that: According to the distance and angle between the laser rangefinder and the two points , the formula for calculating the mutual distance between two points using the cosine theorem is: ; in, is the distance between two points, and are the distances between the laser rangefinder and the two points respectively.

5. The laser diameter measurement method according to claim 1, characterized in that: According to the mutual distance of three points and the formula of the diameter of the circumscribed circle, the steps of calculating the diameter of the pipe wall section include: Note that any three points on the cross section of the tube wall to be tested are point A, point B and point C. According to Heron's formula, calculate the area of ​​the triangle formed by the three points. : ; Among them, p is the semi-perimeter of the triangle, a, b and c are the distances between the three points, that is, AB=a, BC=b, CA=c; the semi-perimeter p of the triangle is: ; Substituting equation (2) into equation (1), the area of ​​the triangle is for: ; Lead out from point C through The auxiliary line CD of the origin O of the circumscribed circle of The intersection of the circumscribed circles of Connect DA. Since ∠CBA=∠CDA, and ∠CAD is a right angle, we get: ; Substituting equation (5) into equation (4), we get The diameter d of the circumscribed circle is: .

6. A laser diameter measuring instrument, characterized in that: It includes a distance measurement module, an angle adjustment module and a control unit; The distance measurement module is used to measure the distance to the target point; The distance measuring module is arranged on the angle adjusting module, and the angle adjusting module is used to drive the distance measuring module to rotate in two mutually perpendicular planes; The control unit is used to receive and store the distance data measured by the distance measuring module and the rotation angle data of the angle adjustment module. The control unit is also used to calculate the diameter of the tube wall section of the tube body to be measured based on the distance data and the rotation angle data.

7. The laser diameter measuring instrument according to claim 6, characterized in that: It also includes a bracket module, and the angle adjustment module is arranged on the bracket module.

Images