A method for adjusting the attitude of a geometric center axis

Abstract

This invention relates to a method for adjusting the attitude of a geometric center axis, a technique used in the field of precision assembly technology for satellite structural subsystems. This method utilizes a multi-device joint measurement method based on a laser tracker and theodolite-cubic mirror alignment, meeting the requirements for high-precision attitude parameter adjustment for large, complex spacecraft or process equipment. An electronic latitude and longitude system, capable of automatically capturing, calculating, analyzing, and judging collimated images, fully automates on-site data measurement and operational guidance, enabling precise quantification of adjustment operations. This approach replaces the previous practice of manual aiming and estimation, improving the efficiency of adjustment operations and reducing the risk of miscalculations.

Description

Technical Field

[0001] The present invention belongs to the technical field of satellite structural subsystem precision assembly, and in particular relates to a method for adjusting the attitude of a geometric center axis. Background Art

[0002] To ensure the on-orbit performance of satellite payloads (such as SADA and antennas), it is necessary to strictly guarantee the accuracy and reliability of the payload posture during the development phase of the satellite structural subsystem. Due to the small size of the payload itself and the high requirements for attitude accuracy (such as the technical indicator that the attitude error is no more than 0.005°), the force-bearing parts adjusted during the installation process are cylindrical (or rectangular) with a small area, making the direction and strength of the force extremely difficult to control. Currently, laser tracking contact measurement is used to sample the shape of the payload, and the central axis is obtained through mathematical fitting calculations. The attitude parameters relative to the product assembly reference are then calculated. After analysis, if the installation error is greater than the indicator parameter, adjustment measures are formulated to approach the ideal error area, and adjustments are made. The adjusted payload attitude parameters are calculated and analyzed again. After repeated adjustments and measurements, the attitude error allowable area is gradually approached.

[0003] As satellite structures grow in size, payload installation locations become relatively higher. For some satellites with special functional requirements, payload attitude accuracy requirements are increased. Existing adjustment and measurement methods have many defects and deficiencies. Specifically,

[0004] (1) Low measurement efficiency. The entire process of posture parameter measurement uses a contact measurement method based on laser tracking technology. It requires full-area multi-point sampling of the product shape. Data calculation and analysis involve a large number of sample points. The single measurement time is long and the operator needs to sample the overall shape of the load multiple times, which takes a lot of time.

[0005] (2) Poor process guidance. The adjustment guidance idea of ​​"status verification and gradual approximation" is adopted, which cannot provide real-time monitoring and precise control of the adjustment operation. Repeated overall sampling is required to confirm the installation status, resulting in insufficient effectiveness of the adjustment operation, a large number of invalid operations or excessive operations, and high operation intensity. The application of existing methods requires a large amount of product mainline development time, which has become a bottleneck problem that restricts the guarantee of product development nodes. Summary of the Invention

[0006] The present invention aims to provide a method for adjusting the attitude of a geometric center axis. This method utilizes a multi-device joint measurement method based on laser tracking and theodolite-cube alignment to meet the requirements for high-precision attitude parameter adjustment for large, complex spacecraft or process equipment. By employing an electronic latitude and longitude system capable of automatically capturing, calculating, analyzing, and judging collimated images, on-site data measurement and operational guidance are fully automated, enabling precise quantification of adjustment operations. This approach replaces the previous practice of manual aiming and estimation, improving the efficiency of adjustment operations and reducing the risk of miscalculations.

[0007] The above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

[0008] A method for adjusting the attitude of a geometric center axis includes the following steps:

[0009] (1) Use a laser tracker to sample the external surface of the load, obtain a set of sampling points, fit a regular shape, and construct the geometric center axis L through calculation and analysis; sample the load docking surface and positioning hole, fit the reference surface and reference hole, construct a reference circle through the center of the reference hole, use the center of the reference circle as the coordinate origin, the reference surface normal as the X-axis, and the line connecting the centers of the reference holes as the Y-axis to construct an assembly reference coordinate system, calculate the attitude parameters of the geometric center axis L relative to the assembly reference J, and express them as the pitch attitude angle α and azimuth attitude angle β of the axis relative to the assembly reference J;

[0010] (2) Install the optical cube mirror on the load and adjust the installation posture of the optical cube mirror to ensure that the following requirements are met: the normal line of the mirror working surface is parallel to the load geometric center axis L, or the plane where the two are located is perpendicular to any reference axis of the assembly reference coordinate system; the normal line of the mirror working surface is within the monitoring range of the theodolite;

[0011] (3) Use the theodolite to measure the alignment of the optical cubic mirror working surface, and record the initial values ​​of the theodolite azimuth and elevation angles as H0 and V0 respectively;

[0012] (4) According to the theoretical positional relationship between the geometric center axis L and the assembly datum J, the theoretical pitch attitude angle α0 and the azimuth attitude angle β0 are calculated. The corresponding adjustment amounts are α0-α and β0-β. When the load geometric center axis L is in the theoretical state, the theoretical parameters of the theodolite are H0+α0-α and V0+β0-β respectively.

[0013] (5) Adjust the load according to the theoretical parameters in step (4), and the instant reading of the theodolite is (H i , V i ); calculate the deviation between the instant reading and the theoretical parameter of step (4), and adjust the theodolite reading to the theoretical parameter of step (4) as the goal, and perform the adjustment operation until the theodolite reading enters the error allowable area, and stop the adjustment operation.

[0014] It also includes an adapter, one end of which is connected to the external surface of the load, and the other end is connected to the optical cubic mirror. The normal direction of the connection surface between the adapter and the optical cubic mirror is parallel to the geometric center axis L of the load.

[0015] The adapter is wedge-shaped, the inclined surface of the wedge-shaped adapter is connected to the external surface of the load, and the side plane of the wedge-shaped adapter is connected to the optical cubic mirror.

[0016] The contact surface between the adapter and the optical cube mirror is square with a side length of 25-35mm.

[0017] The adapter is connected to the load by screw connection or adhesive connection, and the adapter is connected to the optical cube mirror by adhesive connection.

[0018] The optical cubic mirror is fixed to the end of the load.

[0019] With the horizontal direction as zero degree, the normal angle range of the collimating working surface of the optical cubic mirror is -47° to 47°.

[0020] The theodolite is an electronic theodolite that includes an image recognition and calculation module, and can automatically adjust the angle fine-tuning mechanism of the instrument until the optical sighting line is aligned with the collimated image.

[0021] After the adjustment is completed, use a laser tracker to recheck the attitude parameters of the load geometric center axis L relative to the assembly reference coordinate system. If it does not meet the design requirements, return to step (5) to readjust and re-measure until the requirements are met.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The geometric center axis attitude adjustment method of the present invention adopts a multi-device joint measurement method, separates the state detection and process monitoring of the load adjustment stage, and applies a measurement method suitable for the on-site conditions and structural characteristics of the measured features. It not only takes advantage of the high efficiency and precision of the laser tracking measurement system for measuring the static dimensions of the product, but also takes advantage of the real-time and continuous observation of the motion attitude of the theodolite system, rather than using a single device to measure the entire process.

[0024] (2) The method for adjusting the attitude of the geometric center axis of the present invention preferably adopts an electronic theodolite system with an automatic acquisition / analysis function of the collimation image. The system can be manually preliminarily adjusted to a collimated state. After the collimation image is obtained, the measuring instrument directly processes the image and data of the collimation image, calculates and displays the attitude parameter state value of the payload cubic mirror in real time, and fully automates the on-site data measurement and operation guidance. The adjustment operation is accurately quantified, which changes the previous situation of human eye aiming and manual estimation, improves the efficiency of the adjustment operation implementation, and reduces the risk of calculation errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the debugging method of the present invention;

[0026] Figure 2 Schematic diagram of the detection object posture and the optical cubic mirror alignment measurement surface selection of the present invention;

[0027] Figure 3 This is a flow chart for implementing the measurement method of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments:

[0029] like Figure 1 The figure shows a schematic diagram of the geometric center axis adjustment method of the present invention, which includes a payload 1, a wedge-shaped adapter 2, an optical cubic mirror 3, a laser tracker 4, and a theodolite 5. The geometric center axis refers to the geometric center axis of a regular shape component represented by a satellite payload. The satellite assembly station is strictly adjusted, and one of the reference planes of the assembly reference (shown in FIG. Figure 1 The geometric center axis of load 1 is in a horizontal state with a reference axis (shown as the XOY plane) located on the aforementioned reference plane. Figure 1 The Y-axis in the figure is theoretically orthogonal, and the actual angular deviation between the two (theoretical value is 90°) is not within the range of attitude parameter adjustment. By measuring the external surface of load 1 and obtaining its geometric characteristics through mathematical fitting calculation methods, further analysis can determine its attitude parameters relative to assembly datum J. A laser tracker 4 is used as a state measurement device for the initial and final attitudes of the geometric characteristics of load 1's axes. A theodolite 5 is used as a process monitoring device for load 1's axis adjustment operations. The optical cubic mirror 3 deployed on load 1 is the measurement object for process monitoring.

[0030] like Figure 2 The figure shows a schematic diagram of the posture of the detection object and the selection of the alignment measurement surface of the optical cubic mirror in the present invention. Due to the limited range of the electronic theodolite's collimation angle, if the measured axis of the product forms a large angle with the bottom surface of the assembly reference, the alignment direction of the monitoring cubic mirror working surface may exceed the instrument's sight range. It is necessary to reasonably convert it through the bevel design of the adapter 2 to ensure that the instrument can achieve collimation measurement.

[0031] Figure 3 The figure shows a flow chart of the measurement method of the present invention. The specific steps are as follows:

[0032] 1. Measurement of the initial state of the load geometric center axis

[0033] (1) Using a laser tracker, the product's external surface is sampled over a large area and uniformly to obtain a sampling point set W, which is then fitted into a cylinder. After calculation and analysis, the geometric center axis L is constructed. The load assembly reference features are sampled, i.e., the docking surface and its positioning holes are sampled, and the reference surface and reference hole are fitted. The reference circle is constructed through the center of the reference hole. The center of the reference circle is used as the coordinate origin, the normal of the reference surface is used as the X-axis, and the line connecting the centers of the reference holes is used as the Y-axis to construct the assembly reference coordinate system. According to the design process file, the assembly reference J is constructed. The attitude parameters of the geometric center axis L relative to the assembly reference J are calculated, which are represented by the pitch attitude angle α and the azimuth attitude angle β of the axis relative to the assembly reference J.

[0034] 2. Installation of optical cube mirror

[0035] (2) Arrange the optical cube mirror at the appropriate position of the load (to reduce the probability of blocking the collimating light, it is chosen to be set near the end in the example). The mirror body is connected to the product through a wedge-shaped adapter. A connection method that is firm to install and easy to disassemble is selected to ensure that the normal line of the collimating working surface of the mirror body is approximately parallel to the central axis of the load, or that the plane where the two are located is approximately perpendicular to one of the reference axes of the assembly reference (see Figure 1). Figure 1 The Y-axis in the image); the normal to the mirror's alignment surface is within the monitoring range of the electronic theodolite (with the horizontal direction as zero degrees, the electronic theodolite's pitch measurement range generally does not exceed ±47°). This project does not involve rotation angle parameters around the payload's geometric center axis; only one mirror surface needs to be aligned and measured to monitor attitude changes in two directions.

[0036] 3. Load geometric center axis monitoring process

[0037] (3) Use the electronic theodolite to align the optical cube mirror on the wedge adapter and record the initial values ​​of the electronic theodolite's azimuth and elevation angles (H0, V0);

[0038] (4) According to the theoretical positional relationship between the axis and the assembly datum J, the theoretical pitch attitude angle α0 and the azimuth attitude angle β0 are calculated. The corresponding adjustment amounts are α0-α and β0-β. According to the above analysis, when the load geometric center axis is in the theoretical state, the theoretical parameters of the electronic theodolite should be (H0+α0-α, V0+β0-β).

[0039] (5) The electronic theodolite monitors the load adjustment process. The instrument has the function of automatic acquisition / analysis of collimated images and can calculate and display the load attitude parameter status value (H i , V i ); Based on the above analysis data, formulate a load adjustment plan, adjust the load appropriately, combine the theoretical values ​​obtained above, revise the load adjustment plan, and continue to adjust the load until the deviation between the electronic theodolite reading and the theoretical parameters meets the load technical requirements.

[0040] 4. Confirmation of the final state of the load geometric center axis

[0041] (6) According to step (2), the laser tracker samples and analyzes the geometric center axis of the load, and evaluates the posture parameters of the geometric center axis L of the load relative to the assembly reference J. If the technical requirements are met, the adjustment is terminated and the final data is recorded; otherwise, the adjustment is continued in the direction of the theoretical value, and the laser tracker is used again to measure and evaluate the posture parameters of the geometric center axis L of the load relative to the assembly reference J until the technical requirements are met.

[0042] The above description is only the best specific implementation method of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

[0043] The contents not described in detail in the specification of the present invention belong to the common knowledge of professionals in this field.

Claims

1. A method for adjusting the attitude of a geometric center axis, characterized by: The following steps are involved: (1) Using a laser tracker (4) to sample the external surface of the load (1), obtaining a set of sampling points, fitting a regular shape, and constructing a geometric center axis L through calculation and analysis; Sample the docking surface and positioning hole of the load (1), fit the reference surface and reference hole, construct a reference circle through the center of the reference hole, use the center of the reference circle as the coordinate origin, use the normal of the reference surface as the X axis, and the line connecting the centers of the reference holes as the Y axis to construct the assembly reference coordinate system, calculate the attitude parameters of the geometric center axis L relative to the assembly reference J, and express them as the pitch attitude angle α and azimuth attitude angle β of the axis relative to the assembly reference J; (2) Install the optical cubic mirror (3) on the load (1), and adjust the installation posture of the optical cubic mirror (3) to ensure that the following requirements are met: the normal line of the mirror working surface is parallel to the geometric center axis L of the load (1), or the plane where the two are located is perpendicular to any reference axis of the assembly reference coordinate system; the normal line of the mirror working surface is located in the monitoring range of the theodolite (5); (3) Using the theodolite (5) to measure the alignment of the working surface of the optical cubic mirror (3), and recording the initial values ​​of the azimuth angle and the pitch angle of the theodolite (5) as H0 and V0 respectively; (4) According to the theoretical positional relationship between the geometric center axis L and the assembly reference J, the theoretical pitch attitude angle α0 and the azimuth attitude angle β0 are calculated, and the corresponding adjustment amounts are α0-α and β0-β. When the geometric center axis L of the load (1) is in the theoretical state, the theoretical parameters of the theodolite (5) are H0+α0-α and V0+β0-β respectively; (5) According to the theoretical parameters of step (4), the load (1) is adjusted, and the instant reading of the theodolite (5) is (H i , V i ); Calculate the deviation between the instant reading and the theoretical parameter of step (4), adjust the reading of the theodolite (5) to the theoretical parameter of step (4) as the goal, perform the adjustment operation, and stop the adjustment operation when the reading of the theodolite (5) enters the error allowable area.

2. A method for adjusting the geometric center axis posture according to claim 1, characterized in that: It also includes an adapter seat (2), one end of which is connected to the external surface of the load (1), and the other end is connected to the optical cubic mirror (3), and the normal direction of the connection surface between the adapter seat (2) and the optical cubic mirror (3) is parallel to the geometric center axis L of the load (1).

3. The method for adjusting the geometric center axis posture according to claim 2, characterized in that: The adapter seat (2) is wedge-shaped, the inclined surface of the wedge-shaped adapter seat (2) is connected to the external surface of the load (1), and the side plane of the wedge-shaped adapter seat (2) is connected to the optical cubic mirror (3).

4. The method for adjusting the geometric center axis posture according to claim 2, characterized in that: The contact surface between the adapter (2) and the optical cubic mirror (3) is square, with a side length of 25-35 mm.

5. The method for adjusting the geometric center axis posture according to claim 2, characterized in that: The adapter seat (2) and the load (1) are connected in a screw connection or adhesive connection manner, and the adapter seat (2) and the optical cubic mirror (3) are connected in a adhesive connection manner.

6. The method for adjusting the geometric center axis posture according to claim 1, characterized in that: The optical cubic mirror (3) is fixed to the end of the load (1).

7. The method for adjusting the geometric center axis posture according to claim 1, characterized in that: With the horizontal direction as a zero-degree angle, the normal angle range of the collimating working surface of the optical cubic mirror (3) is -47° to 47°.

8. The method for adjusting the geometric center axis posture according to claim 1, characterized in that: The theodolite (5) is an electronic theodolite comprising an image recognition and calculation module, and can automatically adjust the angle fine-tuning mechanism of the instrument until the optical sighting line is aligned with the collimated image.

9. The method for adjusting the geometric center axis posture according to claim 1, characterized in that: After the adjustment is completed, the laser tracker (4) is used to recheck the posture parameters of the geometric center axis L of the load (1) relative to the assembly reference coordinate system. If it does not meet the design requirements, return to step (5) to readjust and re-measure until the requirements are met.

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