Space pose measurement method for large component hoisting butt joint

Abstract

This invention discloses a spatial pose measurement method for the hoisting and docking of large components, belonging to the field of spatial pose measurement technology. The method includes establishing a first coordinate system based on the space of the hoisting and docking site, a second coordinate system based on the position of the measurement assembly system, a third coordinate system based on the sensor position, and a fourth coordinate system based on the support rod position. The method obtains the transformation relationships between the first, second, third, and fourth coordinate systems, acquires the coordinates of the support rod relative to the measurement assembly system in the second coordinate system, and obtains the pitch angle of the measurement assembly system relative to the support rod. The acquired data is then transformed in each coordinate system to obtain the spatial position of the large component relative to the support rod. This invention combines real-time measurement of the position and attitude of the measuring fixture with the inner envelope structure characteristics of the hoisting equipment (large components typically use gantry cranes) to achieve collision risk assessment throughout the entire hoisting process, effectively controlling the risk of collision damage during hoisting.

Description

Technical Field

[0001] This invention relates to the field of spatial attitude measurement technology, and in particular to a spatial attitude measurement method and system for hoisting and docking large components. It is especially suitable for high-precision real-time attitude measurement and docking guidance of large components in the fields of aviation, aerospace and shipbuilding during the hoisting process. Background Technology

[0002] In the final assembly of large equipment such as aircraft and ships, the hoisting and docking of large components is a critical step, and the accuracy and efficiency of their attitude measurement directly determine the assembly quality and efficiency. These hoisted components are often enormous in size and weight, and are "non-cooperative targets," meaning their surfaces cannot be pre-installed with cooperative markers for measurement. Furthermore, the hoisting environment is complex, with issues such as obstructed views and vibration interference, placing extremely high demands on the accuracy, robustness, and real-time performance of the measurement system.

[0003] Currently, the hoisting and docking of large components largely relies on manual visual inspection, trial and error, or measurement methods based on large instruments such as total stations and laser trackers. Manual methods are inefficient, inaccurate, and prone to errors; while large instruments offer higher accuracy, they suffer from drawbacks such as high cost, cumbersome measurement procedures, the need for manual aiming, and poor real-time performance, making them unsuitable for the demands of modern intelligent and automated assembly. In recent years, measurement methods based on vision or line structured light have been developed, but single sensors have limitations in measurement range, accuracy, and resistance to occlusion. Furthermore, machine vision suffers from limitations such as large data volumes and poor real-time performance, hindering its application in aero-engine collision risk assessment and early warning.

[0004] Chinese invention patent application CN202310495587.7 discloses a spatial attitude measurement method and system for hoisting an aero-engine. This invention establishes a global coordinate system, a measurement coordinate system, a reflection reference surface coordinate system, and a working surface coordinate system on the aero-engine. By irradiating a laser line onto an auxiliary component and reflecting a portion of the laser line onto the reflection reference surface, it ensures that the attitude of the aero-engine and engine mount can be measured in real time throughout the hoisting process, effectively solving the problem of spatial attitude measurement for aero-engines. Chinese invention patent application CN201710408940.8 discloses a method for accurate position measurement and alarm during the installation, disassembly, and hoisting of large components of a hydro-generator. This method mainly uses an angle monitoring alarm unit installed on the hoisting component at the hoisting site and multiple displacement monitoring alarm units evenly distributed around the hoisting component to monitor the tilt angle and distance from the predetermined position of the hoisting component in real time. The monitoring data is then uploaded to a background analysis and monitoring system in real time, effectively improving the efficiency and quality of the hoisting work.

[0005] However, the above methods are designed for large components that can be installed with rigid supports in specific scenarios. They are not very universal and cannot obtain the geometric dimensions (usually the radius) of the rigid supports with high precision. Summary of the Invention

[0006] The purpose of this invention is to provide a spatial pose measurement method for the hoisting and docking of large components, based on existing technology. This method uses a multi-2D laser profilometer combination system to measure the relative position of the hoisting support rods, providing real-time and accurate pose data for the hoisting equipment, while effectively controlling the collision risk during the hoisting process of large components.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for measuring the spatial pose of a large component during hoisting and docking, comprising: S1: Establish the first coordinate system based on the space of the hoisting docking site, establish the second coordinate system based on the position of the measurement assembly system, establish the third coordinate system based on the position of the sensor, and establish the fourth coordinate system based on the position of the support rod; S2: Obtain the transformation relationships between the first coordinate system, the second coordinate system, the third coordinate system, and the fourth coordinate system; S3: Obtain the coordinates of the support rod relative to the measurement assembly system in the second coordinate system, as well as the pitch angle of the measurement assembly system relative to the support rod; S4: Transform the data obtained in S3 into various coordinate systems to obtain the spatial position of the large component relative to the support rod.

[0008] In the above technical solution, the measurement assembly system includes a rigid measuring fixture fixed to the bottom of the large component being hoisted, and a laser profilometer fixed to the rigid measuring fixture, wherein the laser profilometer is a sensor.

[0009] In the above technical solution, the rigid measuring fixture is equipped with three laser profilometers at different positions, and a third coordinate system is established based on the positions of the three laser profilometers.

[0010] In the above technical solution, the laser beams emitted by the three laser profilometers are projected onto the top surface of the hoisting support rod, and intersect with the hoisting support rod to generate three feature points; The two-dimensional data of the light stripes corresponding to the three feature points are transformed in the second coordinate system to obtain the three-dimensional coordinates of the feature points. Based on the geometric model constraints of the support rod, the three-dimensional coordinates of the center of the top surface of the support rod are fitted and calculated, and the spatial position, pitch angle and roll angle of the support hole of the hoisting large component in the first coordinate system are calculated simultaneously.

[0011] In the above technical solution, the support rod is cylindrical, and the feature point is located at the junction of the top surface and the side surface of the support rod.

[0012] In the above technical solution, the geometric model constraint is a spatial circle constraint, and the synchronous solution includes: The coordinates of three edge points relative to their own linear structure in the third coordinate system are obtained using three laser profilometers. By using the constraints of the spatial circle, the trajectory equation of the center of the measured circle in the second coordinate system is obtained; Solve the trajectory equation to obtain the spatial coordinates of the center of the measured circle in the second coordinate system and the radius of the measured circle.

[0013] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: This invention is based on non-cooperative target measurement, utilizing the object's own geometric features for measurement. It eliminates the need for pre-installing any cooperative markers on the large components being measured, thus offering strong adaptability. It can simultaneously obtain high-precision spatial five-DOF pose and key assembly dimensions, providing comprehensive information. The symmetrical layout of multiple sensors creates measurement redundancy, and combined with rigid tooling and precise calibration, effectively reduces single-point measurement errors and occlusion effects, resulting in high measurement accuracy and good repeatability. The high-speed measurement frequency enables real-time calculation and output of pose information, meeting the needs of dynamic guidance during hoisting processes.

[0014] The system boasts high integration, a compact structure, and a single type of sensor, facilitating installation, calibration, and maintenance, and allowing for easy integration into existing hoisting equipment. Based on the relative positional relationship between the hoisted large component and the measuring fixture, combined with real-time measurements of the fixture's position and attitude, and leveraging the internal envelope structure characteristics of the hoisting equipment (large components typically utilize gantry cranes), it enables a comprehensive collision risk assessment of the hoisted large component throughout the entire hoisting process, effectively controlling the risk of collision damage during hoisting. Attached Figure Description

[0015] The present invention will be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 This is a flowchart illustrating this embodiment; Figure 2 This is a schematic diagram of the measurement combination system in this embodiment; Figure 3 It is the spatial geometric relationship of the pitch angle of the measured circle; Figure 4 It is the spatial geometric relationship of the roll angle of the measured circle. Detailed Implementation

[0016] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0017] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0018] Example 1 This implementation example Figure 1 As shown, it includes the following steps: Step S1: Establish a global coordinate system (first coordinate system) in the spatial direction of the hoisting and docking site, establish a measurement system coordinate system (second coordinate system) based on the position of the combined measurement system, establish a sensor coordinate system (third coordinate system) based on the sensor position, and establish a support rod coordinate system (fourth coordinate system) based on the support rod's own position.

[0019] The combined measurement system includes a rigid measuring fixture, on which three 2D laser profilometers are symmetrically distributed along the axis. The second coordinate system is mainly established based on the position of the rigid measuring fixture.

[0020] A 2D laser profilometer is used as the sensor, and a third coordinate system is established based on the relative positions of the three sensors.

[0021] Step S2: Once the four coordinate systems are determined, calibrate them to obtain the transformation relationships between the first, second, third, and fourth coordinate systems.

[0022] Step S3: Obtain the pitch angle of the combined measurement system relative to the support rod, and the spatial coordinates of the measurement model relative to the support rod.

[0023] In this embodiment, the rigid measuring fixture is fixedly installed at the bottom of the large hoisting component, so that the combined measuring system moves together with the large component.

[0024] Controlling the movement of the hoisting equipment causes the laser beam emitted by the 2D laser profilometer to be projected onto the top surface of the hoisting support rod, and the intersection of the laser beam and the hoisting support rod generates three feature points.

[0025] Two-dimensional data of light stripes output by a 2D laser profilometer are acquired, and this data is converted to the coordinate system of the combined measurement system to obtain the three-dimensional coordinates of the feature points.

[0026] Based on the geometric model constraints of the hoisting support rod, the three-dimensional coordinates of the center of the top surface of the hoisting support rod are fitted and calculated, and the three-dimensional position of the hoisting support hole of the large component in the global coordinate system, the two-axis attitude angles (pitch angle and roll angle), and the key geometric dimensions of the top surface of the hoisting support rod are obtained simultaneously.

[0027] The calculated position, attitude, and radius data are output to the hoisting control system to achieve real-time guidance and collision avoidance control during the hoisting process.

[0028] The synchronous solution process is as follows: Three 2D laser profilometers can be used to obtain the spatial coordinates of three edge points relative to their own line structured light sensor coordinate system. ,in , and It is a constant value. Based on coordinate transformation theory, it can be calculated. , , Coordinates in the measurement system coordinate system: In the formula , and These represent the rotations of the individual line structured light sensor's own coordinate system around the x, y, and z axes in the measurement system's coordinate system, respectively. , , These are the coordinates of the edge points under the corresponding line structured light sensor. , , i The coordinates of the origin of a single line structured light sensor relative to the coordinate system of the measurement system are spatial coordinates. .

[0029] Let the spatial coordinates of the center of the measured circle in the coordinate system of the measurement system be... By applying the constraints of the spatial circle, the equation of the center of the measured circle is obtained as follows: Solving the above equation of the sphere yields the spatial coordinates of the center of the measured circle in the coordinate system of the measurement system. And the radius of the circle being measured.

[0030] For the two angles of the circle being measured, in the coordinate system of the object being measured o z x z y z z z In the middle, the normal vector The angle of clockwise rotation around the x-axis is defined as the pitch angle. The angle of clockwise rotation around the y-axis is defined as the roll angle. .Depend on , , The coordinates of the three points can be used to obtain the unit normal vector of the plane formed by the three points. : In the formula, These are the plane normal vectors. Components in the x, y, and z axes.

[0031] This implementation example Figure 3 As shown, in In a plane, the unit normal vector of the measured plane. From the origin o z Points A and B are points A in the z-axis. z Projection on the axis. , The pitch angle can be obtained from geometric relationships. The expression: This implementation example Figure 4 As shown, the normal vector Projected onto the x−z plane, the projection vector for We can obtain: On the x−z plane, the projection vector The angle between the zz axis and the positive direction of the zz axis is the roll angle. From geometric relationships, we know that... equal Magnitude and Projection Vector The ratio of the module length, taking into account the direction of rotation, can be used to obtain the roll angle by combining equation (5). The expression: .

[0032] Step S4: Convert the results to the global coordinate system and send them to the hoisting control system through the system control and processing unit for real-time control.

[0033] Example 2 To verify the effectiveness of the present invention, a detailed explanation is given by taking the real-time orientation measurement of a cylindrical support rod with a theoretical radius of R=80.000mm during the hoisting and docking process of a certain type of aircraft as an example.

[0034] Three 2D laser profilometers with a linearity of 26 μm were selected. They were axially symmetrically mounted at 120° intervals on a rigid measuring fixture, forming a combined measurement system. The fixture was reliably fixed to the stationary reference point of the hoisting system. A high-precision standard cylinder (nominal radius 80.000 mm) was placed at the target docking position of the support rod to simulate the target being measured. By controlling the hoisting system, the combined measurement system measured the standard cylinder from different directions, collecting multiple sets of data. The rigid transformation parameters (rotation matrix R and translation vector T) from the coordinate systems of the three line structured light sensors to the coordinate system of the combined measurement system were calibrated.

[0035] The hoisting process begins with the measurement module being lifted. Moving the measurement module allows the line lasers from three 2D laser profilometers to illuminate the surface of the support rod being measured. Data is collected and the two-dimensional coordinates of the three feature points in their respective sensor coordinate systems are output. These coordinates are then uniformly transformed to the coordinate system of the combined measurement system. The transformed coordinates are as follows: According to the spatial circle constraint, the three points P1, P2, P3 satisfy the following system of equations, where (x0, y0, z0) are the coordinates of the circle center and r is the radius: Combining the conditions that the three points and the center of the circle are coplanar, the coordinates of the center and the radius of the circle are obtained as follows: Calculate the plane normal vector : Pitch angle α (rotation about the X-axis): Roll angle β (rotation about the Y-axis): The measured radius deviated from the theoretical value of 80.000 mm by +0.023 mm. After 20 consecutive repeated measurements, the standard deviation of the combined measurement system for the support rod radius was less than 0.05 mm, the standard deviation for the center position measurement was less than 0.03 mm, and the standard deviation for the attitude angle measurement was less than 0.02°. The results demonstrate that the method and system described in this invention can simultaneously and with high precision acquire the spatial pose and key geometric dimensions of the hoisting support rod, fully meeting the measurement requirements for precision hoisting and docking of large components.

[0036] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A method for measuring the spatial pose of a large component during hoisting and docking, characterized in that... include: S1: Establish the first coordinate system based on the space of the hoisting docking site, establish the second coordinate system based on the position of the measurement assembly system, establish the third coordinate system based on the position of the sensor, and establish the fourth coordinate system based on the position of the support rod; S2: Obtain the transformation relationships between the first coordinate system, the second coordinate system, the third coordinate system, and the fourth coordinate system; S3: Obtain the coordinates of the support rod relative to the measurement assembly system in the second coordinate system, as well as the pitch angle of the measurement assembly system relative to the support rod; S4: Transform the data obtained in S3 into various coordinate systems to obtain the spatial position of the large component relative to the support rod.

2. The spatial pose measurement method for hoisting and docking large components according to claim 1, characterized in that: The measurement assembly system includes a rigid measuring fixture fixed to the bottom of the large component being hoisted, and a laser profilometer fixed to the rigid measuring fixture, wherein the laser profilometer is a sensor.

3. The spatial pose measurement method for hoisting and docking large components according to claim 2, characterized in that: The rigid measuring fixture is equipped with three laser profilometers at different positions, and a third coordinate system is established based on the positions of the three laser profilometers.

4. The spatial pose measurement method for hoisting and docking large components according to claim 3, characterized in that: The laser beams emitted by the three laser profilometers are projected onto the top surface of the hoisting support rod, intersecting with the hoisting support rod to generate three feature points; The two-dimensional data of the light stripes corresponding to the three feature points are transformed in the second coordinate system to obtain the three-dimensional coordinates of the feature points. Based on the geometric model constraints of the support rod, the three-dimensional coordinates of the center of the top surface of the support rod are fitted and calculated, and the spatial position, pitch angle and roll angle of the support hole of the hoisting large component in the first coordinate system are calculated simultaneously.

5. The spatial pose measurement method for hoisting and docking large components according to claim 4, characterized in that... The support rod is cylindrical, and the feature point is located at the junction of the top and side surfaces of the support rod.

6. The spatial pose measurement method for hoisting and docking large components according to claim 4, characterized in that... The geometric model constraint is a spatial circle constraint, and the synchronous solution includes: The coordinates of three edge points relative to their own linear structure in the third coordinate system are obtained using three laser profilometers. By using the constraints of the spatial circle, the trajectory equation of the center of the measured circle in the second coordinate system is obtained; Solve the trajectory equation to obtain the spatial coordinates of the center of the measured circle in the second coordinate system and the radius of the measured circle.

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