Method for measuring the distance between reference points in an aircraft assembly jig measurement field using a laser tracker

Abstract

The application belongs to the technical field of aircraft assembly measurement, and particularly relates to a laser tracker measurement method for measuring the distance between reference points in an aircraft assembly tool measurement field, which combines the alignment measurement point and the reference measurement point, uses the absolute ranging function of the laser tracker to calibrate, constructs a ranging coordinate system, and uses the multi-degree-of-freedom precise adjustment structure of the articulated arm robot to position the laser tracker on the extension line of the reference measurement point, so as to realize high-precision measurement of the distance between the two reference measurement points, correct the error of network measurement of the laser interferometer with high precision, and realize high-precision measurement of the large aircraft assembly site.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aircraft assembly measurement, and particularly relates to a laser tracker measurement method for measuring the distance between reference points in an aircraft assembly tool measurement field. BACKGROUND

[0002] In the process of aircraft assembly, a relatively precise large tool measurement field needs to be constructed as the basis for aircraft product assembly measurement. The tool measurement field is generally constructed on a stable foundation and is composed of measurement reference stations and measurement reference points.

[0003] At present, the most precise measurement means is laser tracker measurement. Laser trackers on the market have high precision, but the engineering measurement range is 20 m, and they are greatly affected by light stability and are prone to light interruption, which is not suitable for high-precision measurement of large aircraft assembly sites in complex environments.

[0004] Before the performance of laser trackers is greatly improved, laser interferometer networking is used to measure large aircraft assembly sites, but the laser interferometer networking measurement cannot interrupt the light between two points, and a full-length standard guide rail needs to be set, which is difficult to operate, especially for a large number of point measurements, and it is difficult to ensure measurement accuracy.

[0005] The laser tracker has a ranging function without using a guide rail. The ranging function of the laser tracker is used to precisely measure the distance between the measurement reference points in the aircraft assembly tool measurement field, correct the errors of laser interferometer networking measurement, and achieve high-precision measurement of large aircraft assembly sites to ensure the precision of large aircraft manufacturing. In view of this, the application is proposed. SUMMARY

[0006] The purpose of the application is to provide a laser tracker measurement method for measuring the distance between reference points in an aircraft assembly tool measurement field. The ranging function of the laser tracker is used to precisely measure the distance between the measurement reference points in the aircraft assembly tool measurement field, correct the errors of laser interferometer networking measurement, and achieve high-precision measurement of large aircraft assembly sites.

[0007] The technical solution of the application is as follows:

[0008] A laser tracker measurement method for measuring the distance between reference points in an aircraft assembly tool measurement field, comprising:

[0009] Step 1: Arrange four alignment measurement points on the foundation, which envelope two reference measurement points, the two reference measurement points being a first reference measurement point and a second reference measurement point;

[0010] Step 2: Arrange an auxiliary laser tracker on the foundation to measure and calibrate the two reference measurement points and the four alignment measurement points, and preliminarily calculate the distance L0 between the two reference measurement points.

[0011] Step three, taking the first reference measurement point as the origin, and the line connecting the two reference measurement points as an axis reference direction, a ranging coordinate system is established;

[0012] Step four, arranging a joint arm robot on the foundation, and setting an online laser tracker on the joint arm robot;

[0013] Step five, using the online laser tracker to complex the calibration data of the two reference measurement points and the four alignment measurement points, and inversely calculating the position coordinates of the online laser tracker;

[0014] Step six, in the ranging coordinate system, driving the online laser tracker by the joint arm robot to move towards the extension line of the line connecting the two reference measurement points in the direction of the first reference measurement point, and positioning the online laser tracker on the extension line;

[0015] Step seven, measuring the position distance L1 of the first reference measurement point and the position distance L2 of the second reference measurement point by the online laser tracker, and calculating the accurate distance L3 = | L1- L2| between the two reference measurement points.

[0016] Optionally, in the above-mentioned laser tracker measurement method for measuring the distance between the reference points in the aircraft assembly tool measurement field, the alignment measurement points, the first reference measurement point and the second reference measurement point are reflection points, the center of a reflection target ball is taken, the reflection target ball is supported on the foundation by a reflection seat, and the reflection seat adopts a magnetic reflection seat.

[0017] The line connecting the two reference measurement points is parallel to the upper surface of the foundation;

[0018] The four alignment measurement points are distributed in a rectangular shape, and the line connecting the two reference measurement points is on the symmetry line of the rectangle formed by the four alignment measurement points.

[0019] The rectangle formed by the four alignment measurement points exceeds the two ends of the line connecting the two reference measurement points by 0.5 m in the length direction, and the width is 1 / 20 of the length of the line connecting the two reference measurement points.

[0020] Optionally, in the above-mentioned laser tracker measurement method for measuring the distance between the reference points in the aircraft assembly tool measurement field, the auxiliary laser tracker is arranged within the envelope range of the four alignment measurement points and close to the first reference measurement point.

[0021] Optionally, in the above-mentioned laser tracker measurement method for measuring the distance between the reference points in the aircraft assembly tool measurement field, the joint arm robot is arranged at the extension position of the line connecting the two reference measurement points in the direction of the first reference measurement point.

[0022] Optionally, in the above-mentioned laser tracker measurement method for measuring the distance between the reference points in the aircraft assembly tool measurement field, the online laser tracker is fixed to the end of the joint arm robot by a flange.

[0023] Optionally, in the above-mentioned measurement method of the laser tracker for measuring the distance between reference points in the aircraft assembly tooling measurement field, the online laser tracker is driven by an articulated arm robot, which is divided into large-range coarse driving with an accuracy of more than 1 mm and small-range fine driving with an accuracy of less than 1 mm. The step distance of the small-range fine driving with an accuracy of less than 1 mm to the outward extension line is less than L0×sinα, where α is the angle between the line connecting the online laser tracker and the second reference measurement point and the line connecting the two reference measurement points.

[0024] Optionally, in the above-mentioned method for measuring the distance between reference points in an aircraft assembly tooling measurement field using a laser tracker, the criterion for determining whether the online laser tracker is positioned on the outer extension line is:

[0025] α≤0.003°;

[0026] δ≤L0×sinα, where δ is the distance between the first reference measurement point and the line connecting the online laser tracker and the second reference measurement point.

[0027] Optionally, in the above-mentioned method for measuring the distance between reference points in the aircraft assembly tooling measurement field using a laser tracker, the online laser tracker is positioned on the outer extension line, and the distance between it and the first reference measurement point does not exceed 1m.

[0028] This application has at least the following beneficial technical effects:

[0029] This invention provides a laser tracker measurement method for the distance between reference points in an aircraft assembly tooling measurement field. By combining the alignment measurement point with the reference measurement point, the laser tracker is calibrated using its absolute ranging function to construct a ranging coordinate system. Furthermore, a multi-degree-of-freedom precision adjustment structure of an articulated arm robot is used to position the laser tracker on the outer extension line of the reference measurement point, achieving high-precision measurement of the distance between the two reference measurement points. This method can also accurately correct errors in laser interferometer network measurements, enabling high-precision measurement at large aircraft assembly sites. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the laser tracker measurement method for the distance between reference points in an aircraft assembly tooling measurement field, provided in an embodiment of this application.

[0031] in:

[0032] 1-Foundation; 2-Alignment measurement point; 3-First benchmark measurement point; 4-Second benchmark measurement point; 5-Auxiliary laser tracker; 6-Articulated arm robot; 7-Online laser tracker.

[0033] To better illustrate this embodiment, some content in the accompanying drawings may be omitted, enlarged, or reduced. They are for illustrative purposes only and should not be construed as limiting the scope of this application. Detailed Implementation

[0034] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, and other related parts can be referred to the general design.

[0035] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The word "comprising" as used in this application description indicates that the concept preceding the word encompasses the concepts listed following the word and their equivalents, without excluding other related concepts.

[0036] Furthermore, the terms indicating location used in the description of this application are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation" and "connection" used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0037] A method for measuring the spacing between reference points in an aircraft assembly tooling measurement field using a laser tracker, such as... Figure 1 As shown.

[0038] Step 1: Arrange four alignment measurement points 2 on the foundation 1. The four alignment measurement points 2 enclose two reference measurement points, which are the first reference measurement point 3 and the second reference measurement point 4.

[0039] Find the measurement point 2, the first reference measurement point 3, and the second reference measurement point 4 as the reflection point, take the center of the reflection target ball, and support the reflection target ball on the foundation 1 with the reflection seat. The reflection seat can be a magnetic reflection seat.

[0040] The line connecting the two reference measurement points is parallel to the upper surface of foundation 1.

[0041] The four alignment measurement points 2 are arranged in a rectangle, and the line connecting the two reference measurement points is located on the line of symmetry of the rectangle formed by the four alignment measurement points 2.

[0042] The rectangle formed by the four alignment measurement points 2 extends 0.5m beyond both ends of the line connecting the two reference measurement points in the length direction, and its width is 1 / 20 of the length of the line connecting the two reference measurement points.

[0043] Step 2: Deploy an auxiliary laser tracker 5 on the foundation 1. Use the auxiliary laser tracker 5 to measure and calibrate two reference measurement points and four alignment measurement points 2, and preliminarily calculate the distance L0 between the two reference measurement points.

[0044] The auxiliary laser tracker 5 is positioned within the envelope of the four alignment measurement points 2 and is close to the first reference measurement point 3.

[0045] The current upper limit for L0 is 80m.

[0046] Step 3: Establish a distance measurement coordinate system with the first reference measurement point 3 as the origin and the line connecting the two reference measurement points as a reference axis.

[0047] Step 4: Deploy the articulated arm robot 6 on the foundation 1, and install the online laser tracker 7 on the articulated arm robot 6.

[0048] The articulated arm robot 6 is positioned at the outer edge of the line connecting the two reference measurement points, extending towards the first reference measurement point 3.

[0049] The online laser tracker 7 is connected to the end of the articulated arm robot 6 via a flange.

[0050] Step 5: Use the online laser tracker 7 to recompile the calibration data of the two reference measurement points and the four alignment measurement points 2, and then reverse-engineer the position coordinates of the online laser tracker 7.

[0051] Step 6: In the ranging coordinate system, the articulated arm robot 6 drives the online laser tracker 7 to move towards the outer extension line of the line connecting the two reference measurement points towards the first reference measurement point 3, thereby positioning the online laser tracker 7 on the outer extension line.

[0052] The articulated arm robot 6 drives the online laser tracker 7, which is divided into large-range coarse driving with an accuracy of more than 1 mm and small-range fine driving with an accuracy of less than 1 mm. The step distance of the small-range fine driving with an accuracy of less than 1 mm to the outward extension line is less than L0×sinα, where α is the angle between the line connecting the online laser tracker 7 and the second reference measurement point 4 and the line connecting the two reference measurement points.

[0053] The articulated arm robot 6 can first be roughly moved over a large range with an accuracy of more than 1 mm to move the online laser tracker 7. After the online laser tracker 7 gets close to the outer extension line, it can then be finely moved over a small range of less than 1 mm to move the online laser tracker 7. Finally, the online laser tracker 7 is positioned on the outer extension line. Before finely moving the online laser tracker 7 over a small range of less than 1 mm, step five can be repeated.

[0054] The criteria for determining whether the online laser tracker 7 is positioned on the outer extension line are as follows:

[0055] α≤0.003°; for extremely high measurement accuracy requirements, α≤0.001° can be set.

[0056] δ≤L0×sinα, where δ is the distance between the first reference measurement point 3 and the line connecting the online laser tracker 7 and the second reference measurement point 4.

[0057] The online laser tracker 7 is positioned on the outer extension line, and the distance between it and the first reference measurement point 3 is no more than 1m.

[0058] Step 7: Measure the position distance L1 of the first reference measurement point 3 and the position distance L2 of the second reference measurement point 4 using the online laser tracker 7, and calculate the precise distance L3 between the two reference measurement points = |L1-L2|.

[0059] In a specific example, L1 = 81000.00001 mm, L2 = 1000.0082 mm, and L3 = 79999.99181 mm were calculated. The error with the standard 80 mm is no more than 0.01 mm, which shows extremely high measurement accuracy.

[0060] The above-described embodiment discloses a laser tracker measurement method for measuring the distance between reference points in an aircraft assembly tooling measurement field. By combining a calibration measurement point with a reference measurement point, the laser tracker's absolute ranging function is used for calibration to construct a ranging coordinate system. Furthermore, a multi-degree-of-freedom precision adjustment structure of an articulated arm robot is used to position the laser tracker on the outer edge of the reference measurement point, achieving high-precision measurement of the distance between two reference measurement points. This method is applicable to measuring the distance between reference points in aircraft assembly tooling measurement fields ranging from 30m to 80m or even larger. It can also accurately correct errors in laser interferometer network measurements, enabling high-precision measurement at large aircraft assembly sites.

[0061] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A method for measuring the spacing between reference points in an aircraft assembly tooling measurement field using a laser tracker, characterized in that, include: Step 1: Arrange four alignment measurement points (2) on the foundation (1). The four alignment measurement points (2) enclose two reference measurement points, which are the first reference measurement point (3) and the second reference measurement point (4). Step 2: Set up an auxiliary laser tracker (5) on the foundation (1), and use the auxiliary laser tracker (5) to measure and calibrate two reference measurement points and four alignment measurement points (2), and preliminarily calculate the distance L0 between the two reference measurement points; Step 3: Establish a distance measurement coordinate system with the first reference measurement point (3) as the origin and the line connecting the two reference measurement points as a reference axis. Step 4: Arrange the articulated arm robot (6) on the foundation (1) and set up an online laser tracker (7) on the articulated arm robot (6); Step 5: Use the online laser tracker (7) to recompile the calibration data of the two reference measurement points and the four alignment measurement points (2), and reverse the position coordinates of the online laser tracker (7); Step 6: In the ranging coordinate system, the articulated arm robot (6) drives the online laser tracker (7) to move towards the outer extension line of the line connecting the two reference measurement points towards the first reference measurement point (3), and position the online laser tracker (7) on the outer extension line; Step 7: Measure the position distance L1 of the first reference measurement point (3) and the position distance L2 of the second reference measurement point (4) using an online laser tracker (7), and calculate the precise distance L3 between the two reference measurement points = |L1-L2|. Find the measurement point (2), the first reference measurement point (3), and the second reference measurement point (4) as the reflection point, take the center of the reflection target ball, and support the reflection target ball on the foundation (1) with the reflection seat. The reflection seat adopts the magnetic reflection seat. The line connecting the two reference measurement points is parallel to the upper surface of the foundation (1); The four alignment measurement points (2) are arranged in a rectangle. The line connecting the two reference measurement points is on the line of symmetry of the rectangle formed by the four alignment measurement points (2). The rectangle formed by the four alignment measurement points (2) extends 0.5m beyond both ends of the line connecting the two reference measurement points in the length direction, and its width is 1 / 20 of the length of the line connecting the two reference measurement points.

2. The measurement method for the distance between reference points in an aircraft assembly tooling measurement field according to claim 1, characterized in that, The auxiliary laser tracker (5) is arranged within the envelope of the four alignment measurement points (2) and close to the first reference measurement point (3).

3. The method for measuring the distance between reference points in an aircraft assembly tooling measurement field using a laser tracker, as described in claim 2, is characterized in that... The articulated arm robot (6) is positioned at the outer edge of the line connecting the two reference measurement points toward the first reference measurement point (3).

4. The method for measuring the distance between reference points in an aircraft assembly tooling measurement field using a laser tracker, as described in claim 3, is characterized in that... The online laser tracker (7) is connected to the end of the articulated arm robot (6) via a flange.

5. The method for measuring the distance between reference points in an aircraft assembly tooling measurement field using a laser tracker, as described in claim 4, is characterized in that... The articulated arm robot (6) drives the online laser tracker (7), which is divided into a large-range coarse drive with an accuracy of more than 1 mm and a small-range fine drive with an accuracy of less than 1 mm. The step distance of the small-range fine drive with an accuracy of less than 1 mm is less than L0*sinα, where α is the angle between the line connecting the online laser tracker (7) and the second reference measurement point (4) and the line connecting the two reference measurement points.

6. The method for measuring the distance between reference points in an aircraft assembly tooling measurement field using a laser tracker, as described in claim 5, is characterized in that... The criteria for determining whether the online laser tracker (7) is positioned on the extension line are: α≤0.003°； δ≤L0*sinα, where δ is the distance between the first reference measurement point (3) and the line connecting the online laser tracker (7) and the second reference measurement point (4).

7. The method for measuring the distance between reference points in an aircraft assembly tooling measurement field using a laser tracker according to claim 6, characterized in that, The online laser tracker (7) is positioned on the outer extension line, and the distance between it and the first reference measurement point (3) is no more than 1m.

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