Geometric central axis attitude adjusting and measuring method

Abstract

The invention relates to a geometric center axis attitude adjusting and measuring method, belongs to the technical field of satellite structure subsystem precision assembly, adopts a multi-equipment combined measurement method based on a laser tracker and theodolite-cubic mirror collimation, and meets the high-precision attitude parameter adjusting and measuring requirements of large and complex spacecrafts or technological equipment. An electronic longitude and latitude system capable of automatically collecting, calculating, analyzing and judging collimated images is adopted, on-site data measurement and operation guidance are completely automated, adjustment operation is accurately quantified, the current situations of human eye aiming and manual estimation in the past are changed, the implementation efficiency of the adjustment operation is improved, and the risk of calculation errors is reduced.

Description

Technical Field

[0001] The 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] In order 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 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 part of the adjustment during the installation process is cylindrical (or rectangular) with a small area, and the direction and strength of the force are extremely difficult to control. Currently, laser tracking contact measurement is used to sample the shape of the payload, obtain the center axis through mathematical fitting calculation, and then solve its attitude parameters relative to the product assembly reference; after analysis, if the installation error is greater than the indicator parameter, formulate adjustment measures that tend to the ideal error area, perform adjustment operations, and calculate and analyze the adjusted payload posture parameters again. After repeated adjustment and measurement operations, it gradually approaches the attitude error allowable area.

[0003] As the size of satellite structures increases, the payload installation position becomes relatively higher. For some satellites with special functional requirements, the payload attitude accuracy requirements are higher. The existing adjustment and measurement methods have many defects and deficiencies. Specifically,

[0004] (1) Low measurement efficiency. The whole process of posture parameter measurement adopts the contact measurement method based on laser tracking technology, which requires full-domain multi-point sampling of the product shape. Data calculation and analysis involve a large number of sample points, and a single measurement time is long. 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 approach" is adopted, which cannot monitor and control the adjustment operation in real time and accurately. 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 restricting the guarantee of product development nodes. Summary of the invention

[0006] The purpose of the present invention is to provide a method for adjusting the attitude of a geometric center axis, which adopts a multi-device joint measurement method based on laser tracking and theodolite-cubic mirror alignment to meet the high-precision attitude parameter adjustment requirements of large and complex spacecraft or process equipment. By adopting an electronic longitude and latitude system with automatic acquisition, calculation, analysis and judgment of collimated images, the data measurement and operation guidance on site are fully automated, and the adjustment operation is accurately quantified, which changes the previous status of human eye aiming and manual estimation, improves the efficiency of adjustment operation implementation, and reduces the risk of calculation errors.

[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 comprises the following steps:

[0009] (1) Use a laser tracker to sample the external surface of the load, obtain a sampling point set, 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, 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 an assembly reference coordinate system, calculate the attitude parameters of the geometric center axis L relative to the assembly reference J, and represent it 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 a theodolite to align the working surface of the optical cube mirror and record the initial values ​​of the theodolite azimuth and elevation angles, H0 and V0 respectively;

[0012] (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. 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 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 cubic mirror by adhesive connection.

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

[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 including an image recognition and calculation module, which 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 posture adjustment method of the present invention adopts a multi-device joint measurement method, separates the state detection and process monitoring of the load installation stage, and applies a measurement method suitable for the field conditions and structural characteristics of the measured features. It not only takes advantage of the laser tracking measurement system's high efficiency and accuracy in measuring the static dimensions of the product, but also takes advantage of the theodolite system's real-time and continuous observation of the motion posture, 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. After the collimation image is obtained after manual preliminary adjustment, the measuring instrument directly processes the image and data of the collimation image, calculates and displays the attitude parameter state value of the load cubic mirror in real time, and fully automates the on-site data measurement and operation guidance, and realizes precise quantification of the adjustment operation, which changes the previous situation of human eye aiming and manual estimation, improves the efficiency of the adjustment operation, and reduces the risk of calculation errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the debugging method of the present invention;

[0026] Figure 2 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;

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

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

[0029] like Figure 1 The schematic diagram of the geometric center axis adjustment method of the present invention is shown, 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 XOY plane) located on the aforementioned reference plane. Figure 1 The Y axis in the figure is theoretically orthogonal, and the actual angle deviation between the two (theoretical value is 90°) is not within the range of attitude parameter adjustment; the external surface of the load 1 can be measured, and its geometric features can be obtained by mathematical fitting calculation method. Further analysis can be performed to know its attitude parameters relative to the assembly reference J. The laser tracker 4 is used as the state measurement device for the initial and final attitudes of the geometric features of the axis of the load 1, the theodolite 5 is used as the process monitoring device for the adjustment operation of the axis of the load 1, and the optical cubic mirror 3 arranged on the load 1 is used as 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 of the present invention. Since the alignment angle range of the electronic theodolite is limited, if the measured axis of the product is at a large angle to the bottom surface of the assembly reference, the alignment direction of the working surface of the monitoring cubic mirror may exceed the sight range of the instrument. It is necessary to reasonably convert it through the bevel design of the adapter 2 to ensure that the instrument can achieve alignment measurement.

[0031] Figure 3 The figure shows a flow chart of the measurement method of the present invention, and 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, a large-scale and uniform sampling of the product's external surface is performed 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 hole are sampled, and the reference surface and reference hole are fitted. A reference circle is constructed through the center of the reference hole. The center of the reference circle is used as the coordinate origin, the reference surface normal is used as the X-axis, and the line connecting the centers of the reference holes is used as the Y-axis to construct an 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 collimation 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. Select a connection method that is firm to install and easy to disassemble. Ensure that the normal line of the collimation 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 (shown in Figure 1). Figure 1 The normal of the mirror collimation working surface is located in the monitoring range of the electronic theodolite (with the horizontal direction as the zero angle, the measurement range of the electronic theodolite in the pitch direction generally does not exceed ±47°). This project does not involve the rotation angle parameter around the geometric center axis of the load. It only needs to align and measure one mirror surface to monitor the attitude changes in two directions.

[0036] 3. Load geometric center axis monitoring process

[0037] (3) The electronic theodolite performs alignment measurement on the optical cube mirror on the wedge-shaped adapter, and records the initial values ​​of the azimuth and elevation angles of the electronic theodolite (H0, V0);

[0038] (4) According to the theoretical positional relationship between the axis 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, 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) in real time. i , V i ); According to the above analysis data, formulate a load adjustment plan, adjust the load appropriately, combine the theoretical value obtained above, revise the load adjustment plan, and continue to adjust the load until the reading of the electronic theodolite deviates from the theoretical parameters and 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 approaching 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 mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

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

Claims

1. A method for adjusting the attitude of a geometric center axis, characterized in that: The following steps are involved: (1) Using a laser tracker (4) to sample the external surface of the load (1), obtain a sampling point set, fit a regular shape, and construct 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, take the center of the reference circle as the coordinate origin, take the normal line 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) Installing the optical cubic mirror (3) on the load (1), and adjusting 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 within the monitoring range of the theodolite (5); (3) using 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 elevation angle of 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 ); calculating the deviation between the instant reading and the theoretical parameter of step (4), adjusting the reading of the theodolite (5) to the theoretical parameter of step (4) as the goal, performing adjustment operation until the reading of the theodolite (5) enters the error allowable area, and stopping the adjustment operation.

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. A 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. A 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 in a square shape, with a side length of 25-35 mm.

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

6. A 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 is characterized in that: With the horizontal direction as an angle of zero, 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 is characterized by: 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. A 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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