An optical calibration device with a large field of view

Abstract

A large field of view optical calibration device, comprising a base and a tripod. A slewing bearing is provided at the upper end of the base, and an azimuth servo assembly is provided on the side wall of the base. A cross beam is provided at the upper end of the slewing bearing, and a central round hole is provided on the cross beam. A workbench passing through the central round hole on the cross beam is provided at the upper end of the base. Three brackets are evenly distributed on the side wall of the workbench, and a reference theodolite is provided on the brackets. A rectangular hole is provided on the upper side end surface of one end of the cross beam, and a vertical beam fixed on the cross beam is provided above the rectangular hole. A lead screw is provided in the vertical beam, and the upper end of the lead screw is connected to a lifting servo assembly installed at the top of the vertical beam. A guide rail is provided on one side of the vertical beam, and a lifting bracket is fitted on the guide rail. The lifting bracket is connected to the lead screw nut on the lead screw. A self-collimation theodolite is installed at the lower end of the lifting bracket through a theodolite bracket. A laser tracker is installed at the upper end of the tripod. The present invention can automatically measure within a range of 360°, and can greatly improve the measurement efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of precision instrument testing and applications, and particularly relates to a large field-of-view optical calibration device. Background Art

[0002] Inertial navigation test equipment or optical test equipment has its own original coordinate system, and it is necessary to calibrate this coordinate system before starting to be put into use. For general application scenarios, a theodolite can be used to complete the calibration of the original coordinate system; for occasions where the zero reference is blocked, two or three theodolites are required to bypass the obstacle of the initial reference and indirectly introduce the reference into the original coordinate system of the equipment to be measured.

[0003] When the reference theodolite cannot complete the measurement at the current fixed position, it is necessary to use one or more reference theodolites as a reference transition. Before moving the position, it is "aligned" with the reference theodolite. After moving the position, it is again "aligned" by aiming at the reference theodolite. The process of the two "alignments" before and after is a coordinate transformation. Usually, the process of moving the position of the self-collimating theodolite is called "station transfer".

[0004] Taking an inertial navigation test turntable as an example, after the turntable is installed in place, it is necessary to use a theodolite to introduce the "north reference" into the plane mirror on the pitching frame. The normal reference of this plane mirror is parallel to the pitching axis, and it has been adjusted by the manufacturer at the time of leaving the factory. Therefore, the pitching axis and the north reference are aligned through coordinate transformation.

[0005] For complex optical test equipment with multiple plane mirrors, it is also necessary to calibrate each plane mirror before starting to use. Since the plane mirrors are distributed around the equipment and not in the same plane, it is impossible to complete the accuracy calibration at one time. It is necessary to change the position of the self-collimating theodolite. Therefore, it is necessary to introduce multiple reference theodolites. The multiple reference theodolites are used as references for each other, and there is a definite transformation matrix between each two of them. After installing the multiple reference theodolites, the azimuth axis and pitching axis vectors of each reference theodolite are tested by a laser tracker, and then the coordinate system is established.

[0006] The existing problems of the existing equipment are that when calibrating the reference of a complex optical system, since the self-collimating theodolite cannot complete the measurement in a single time and "station transfer" is required, the measurement process is extremely cumbersome. Manually moving the self-collimating theodolite is time-consuming and laborious, which is not conducive to realizing standardized and modular production. Summary of the Invention

[0007] The object of the present invention is to provide a large field-of-view optical calibration device to solve the problems in the above background art. During the whole test process, the self-collimating theodolite of this device can automatically lift and rotate, without manual movement, which can greatly improve the test efficiency and avoid introducing human errors.

[0008] The technical solution adopted to achieve the above object is a large field-of-view optical calibration device, including a base and a tripod. A slewing bearing is provided at the upper end of the base, and an azimuth servo assembly is provided on the side wall of the base. A cross beam is provided at the upper end of the slewing bearing, and a central circular hole is provided on the cross beam. A workbench passing through the central circular hole on the cross beam is provided at the upper end of the base. Three brackets are evenly distributed on the side wall of the workbench, and a reference theodolite is provided on the brackets. A rectangular hole is provided on the upper side end surface of one end of the cross beam, and a vertical beam fixed to the cross beam is provided above the rectangular hole. A lead screw is provided in the vertical beam, and the upper end of the lead screw is connected to a lifting servo assembly installed at the top of the vertical beam. A guide rail is provided on one side of the vertical beam, and a lifting bracket is fitted on the guide rail. The lifting bracket is connected to the lead screw nut on the lead screw. A autocollimation theodolite is installed at the lower end of the lifting bracket through a theodolite bracket. A laser tracker is installed at the upper end of the tripod.

[0009] Further, the slewing bearing includes an inner ring and an outer ring. The inner ring is fixed to the upper end of the base, the outer ring is fitted and installed outside the inner ring, the upper end of the outer ring is fixedly connected to the cross beam, and the outer ring is a gear structure; the azimuth servo assembly includes an azimuth servo motor fixed to the side wall of the base, and the output end of the azimuth servo motor is connected to a gear meshing with the outer ring of the slewing bearing.

[0010] Further, three brackets are evenly distributed on the side wall of the workbench along the circumferential direction above the cross beam, and reference theodolites are installed at the upper ends of the three brackets.

[0011] Further, the lifting servo assembly includes a lifting servo motor, and the output end of the lifting servo motor is connected to the upper end of the lead screw; the lead screw is connected to the lifting bracket through a lead screw nut, and the rotation of the lead screw drives the lifting bracket to move up and down along the guide rail through the lead screw nut.

[0012] Beneficial effects

[0013] Compared with the prior art, the present invention has the following advantages.

[0014] 1. Since the present invention has a large lifting range and a 360-degree rotation range, the autocollimation theodolite can observe the top surface, bottom surface and each reference surface of each side of the device to be measured; the three reference theodolites are evenly distributed around the device to be measured, so the reference coordinate system provided by the reference theodolites can also be extended to the entire measurement process;

[0015] 2. The present invention has full-process automatic measurement within 360 degrees, which can greatly improve the measurement efficiency, reduce the interference of human factors, and is conducive to realizing the standardization and modularization of the production process. Description of the drawings

[0016] The present invention will be further described in detail below with reference to the accompanying drawings.

[0017] Figure 1 is a schematic structural diagram of the present invention;

[0018] Figure 2 is a schematic structural diagram of the present invention equipped with a device to be measured;

[0019] Figure 3 is a schematic structural diagram of the workbench in the present invention;

[0020] Figure 4 is a schematic structural diagram of the cross beam in the present invention;

[0021] Figure 5 is a schematic structural diagram of the lifting bracket in the present invention. Specific embodiments

[0022] The present invention will be further described below in conjunction with specific embodiments and the accompanying drawings.

[0023] As Figures 1 - 5 shown, a large field of view optical calibration device includes a base 15 and a tripod 1. A slewing bearing 14 is provided at the upper end of the base 15, and an azimuth servo assembly 13 is provided on the side wall of the base 15. A cross beam 16 is provided at the upper end of the slewing bearing 14, and a central circular hole 12 is provided on the cross beam 16. A workbench 5 passing through the central circular hole 12 on the cross beam 16 is provided at the upper end of the base 15. Three brackets 4 are evenly distributed on the side wall of the workbench 5, and a reference theodolite 3 is provided on the bracket 4. A rectangular hole 18 is provided on the upper side end surface of one end of the cross beam 16, and a vertical beam 11 fixed to the cross beam 16 is provided above the rectangular hole 18. A lead screw 7 is provided in the vertical beam 11, and the upper end of the lead screw 7 is connected to a lifting servo assembly 6 installed at the top of the vertical beam 11. A guide rail 10 is provided on one side of the vertical beam 11, and a lifting bracket 8 is fitted on the guide rail 10. The lifting bracket 8 is connected to a lead screw nut on the lead screw 7. A self-collimation theodolite 9 is installed at the lower end of the lifting bracket 8 through a theodolite bracket 19. A laser tracker 2 is installed at the upper end of the tripod 1.

[0024] The slewing bearing 14 includes an inner ring 141 and an outer ring 142. The inner ring 141 is fixed to the upper end of the base 15, the outer ring 142 is fitted and installed on the outside of the inner ring 141, and the upper end of the outer ring 142 is fixedly connected to the cross beam 16. The outer ring 142 is a gear structure; the azimuth servo assembly 13 includes an azimuth servo motor 131 fixed to the side wall of the base 15, and an output end of the azimuth servo motor 131 is connected to a gear 132 meshing with the outer ring 142 of the slewing bearing 14.

[0025] Three brackets 4 are evenly distributed on the side wall of the workbench 5 along the circumferential direction above the cross beam 16, and a reference theodolite 3 is installed at the upper end of each of the three brackets 4.

[0026] The lifting servo assembly 6 includes a lifting servo motor, and the output end of the lifting servo motor is connected to the upper end of the lead screw 7; the lead screw 7 is connected to the lifting bracket 8 through a lead screw nut, and the rotation of the lead screw 7 drives the lifting bracket 8 to move up and down along the guide rail 10 through the lead screw nut.

[0027] In the present invention, the workbench 5 is supported by the base 15 and passes through the central circular hole 12 on the cross beam 16. Three brackets 4 are evenly distributed along the circumference on the side wall of the workbench 5, and three reference theodolites 3 are installed on the upper end faces of the brackets 4, and there are three reference theodolites.

[0028] A rectangular hole 18 is designed on the upper side end face of one end of the cross beam 16. The rectangular hole 18 is a through-hole structure. The lower end of the lifting bracket 8 slides downward along the guide rail 10 and passes through the rectangular hole 18 to reach the bottom of the lifting position.

[0029] The cross beam 16 is fixed on the outer ring 142 of the slewing bearing 14, and the vertical beam 11 is fixed on the upper side end face of the right end of the cross beam 16. The cross beam 16 drives the vertical beam 11 to rotate around the azimuth axis.

[0030] The working principle of the present invention is that the lifting servo assembly 6 drives the lead screw 7. The lead screw 7 is connected to the lifting bracket 8 through a screw pair structure. The lifting and lowering movement of the lifting bracket 8 indirectly drives the autocollimation theodolite 9 to move up and down along the guide rail 10; the lifting servo assembly 6, the lead screw 7 and the guide rail 10 are all supported by the vertical beam 11, and the vertical beam 11 is integrally installed on the upper end face of one end of the cross beam 16; the lower end face of the cross beam 16 is fixedly connected to the outer ring 142 of the slewing bearing 14, and the azimuth servo assembly 13 drives the outer ring 142 of the slewing bearing 14 to indirectly drive the autocollimation theodolite 9 to rotate around the azimuth axis; the workbench 5 and the base 15 are fixed on the same foundation together. The inner ring surface of the workbench 5 is installed with the device under test 17. Three reference theodolites 3 are fixed on three evenly distributed brackets 4 on the circumference of the workbench 5. Let the three reference theodolites 3 be reference theodolite A, reference theodolite B, and reference theodolite C respectively. Three reference theodolite coordinate systems C1, C2, and C3 are constructed through the laser tracker 2. There are coordinate transformation matrices T1, T2, and T3 between the three coordinate systems; during the measurement process, if the line of sight of the autocollimation theodolite 9 to the reference theodolite A is blocked, then the reference theodolite B or the reference theodolite C can be selected for observation. Finally, through the coordinate transformation matrix, it is equivalent to aiming at the reference theodolite A.

[0031] The base 15 and the workbench 5 are fixed on the same ground surface. The inner ring of the workbench 5 is fixed with the device under test 17. Three reference theodolites 3 are fixed on three evenly distributed brackets 4 on the circumference of the workbench 5. The device under test 17 remains stationary throughout the test process, and only the two axes of the three reference theodolites 3 are in motion.

[0032] Install a slewing bearing 14 at the upper end of the base 15, and install an azimuth servo assembly 13 on the side of the base 15. The azimuth servo assembly 13 drives the outer ring 142 of the slewing bearing 14 to rotate.

[0033] Install a cross beam 16 on the upper end face of the outer ring 142 of the slewing bearing 14. A central round hole 12 is provided at the center of the cross beam 16. A rectangular hole 18 is designed on the upper side of one end of the cross beam 16. The central round tube of the cross beam 16 passes through the workbench 5, and the rectangular hole of the cross beam 16 can pass through the lower end of the lifting bracket 8, thereby driving the autocollimator 9 to also pass through the rectangular hole 18 of the cross beam 16.

[0034] Install a vertical beam 11 on the upper side end face of one end of the cross beam 16. Install a guide rail 10, a lifting servo assembly 6 and a lead screw 7 on the inner plane of the vertical beam 11. The lifting servo assembly 6 drives the lead screw 7 to drive the lifting bracket 8 to slide up and down along the guide rail 10.

[0035] When the present invention is specifically implemented, taking the base 15 and the workbench 5 as the basic supports, the base 15 and the workbench 5 are fixed on the same ground surface, and the upper end face of the workbench 5 is fixed with the device to be measured 17, which is in a static state during the whole measurement process.

[0036] Three brackets 4 are evenly distributed along the circumference on the workbench 5. A reference theodolite 3 is fixed on the upper end face of the bracket 4 with screws. During the whole measurement process, the three reference theodolites 3 rotate the pitch and azimuth axes according to the measurement requirements to provide a reference for the autocollimator.

[0037] Fix the inner ring 141 of the slewing bearing 14 on the upper end face of the base 15 with screws. Install an azimuth servo assembly 13 on the side of the base 15. The gear 132 of the azimuth servo assembly 13 meshes with the outer ring 142 of the slewing bearing 14 and drives the outer ring 142 of the slewing bearing 14 to rotate.

[0038] Fix the cross beam 16 on the upper end face of the outer ring 142 of the slewing bearing 14 with screws. The center of the cross beam 16 is designed as a central round hole 12, and the central round hole 12 is a circular through-hole structure. A rectangular hole 18 is designed on the upper end face of one end of the cross beam 16. The central round hole 12 of the cross beam 16 passes through the workbench 5, and the rectangular hole 18 of the cross beam 16 can pass through the lower end of the lifting bracket 8, thereby driving the autocollimator 9 to also pass through the rectangular hole 18 of the cross beam 16.

[0039] Fix the vertical beam 11 on the upper side end face of one end of the cross beam 16 with screws. Fix the guide rail 10, the lifting servo assembly 6 and the lead screw 7 on the inner plane of the vertical beam 11 with screws, and fix the lead screw nut in the lead screw 7 to the lifting bracket 8 with screws. The lifting servo assembly 6 drives the lead screw 7 to drive the lifting bracket 8 to slide up and down along the guide rail 10.

[0040] Before starting the installation of the device 17 under test, the establishment of the reference coordinate system should be completed. First, fix the tripod 1 on a flat and stable ground, and fix the laser tracker 2 on the tripod 1. Taking the reference theodolite A as the main reference and the reference theodolites B and C as the auxiliary references, sequentially measure the pose information of the three reference theodolites 3, and complete the establishment of the coordinate systems C1, C2, and C3, as well as the calculation of the coordinate transformation matrices T1, T2, and T3.

[0041] In the present invention, an autocollimator is fixed between the pitching axes of the autocollimating theodolite, and a double-sided reference mirror is fixed between the pitching axes of the reference theodolites A, B, and C.

[0042] In the present invention, the number of the reference theodolites 3 is three, which are evenly distributed on the circumference of the workbench 5. In the actual application process, the number of the reference theodolites 3 can be increased or decreased according to the actual situation, which should not only meet the actual measurement requirements but also consider the cost factor.

Claims

1. An optical calibration device with a large field of view angle, comprising a base (15) and a tripod (1), characterized in that, The upper end of the base (15) is provided with a slewing bearing (14), and an azimuth servo assembly (13) is provided on the side wall of the base (15). The upper end of the slewing bearing (14) is provided with a cross beam (16), and a central circular hole (12) is provided on the cross beam (16). The upper end of the base (15) is provided with a workbench (5) passing through the central circular hole (12) on the cross beam (16). Three brackets (4) are evenly distributed on the side wall of the workbench (5), and a reference theodolite (3) is provided on the bracket (4). On the upper side end face of one end of the cross beam (16), there is a rectangular hole (18), and above the rectangular hole (18), there is a vertical beam (11) fixed on the cross beam (16). A lead screw (7) is arranged in the vertical beam (11), and the upper end of the lead screw (7) is connected to a lifting servo assembly (6) installed at the top of the vertical beam (11). One side of the vertical beam (11) is provided with a guide rail (10), and a lifting bracket (8) is fitted on the guide rail (10). The lifting bracket (8) is connected to the lead screw nut on the lead screw (7). The lower end of the lifting bracket (8) is installed with an autocollimation theodolite (9) through a theodolite bracket (19). The upper end of the tripod (1) is installed with a laser tracker (2).

2. The large field of view optical calibration device according to claim 1, wherein The slewing bearing (14) includes an inner ring (141) and an outer ring (142). The inner ring (141) is fixed to the upper end of the base (15), the outer ring (142) is fitted and installed on the outside of the inner ring (141), and the upper end of the outer ring (142) is fixedly connected to the cross beam (16). The outer ring (142) is of a gear structure. The azimuth servo assembly (13) includes an azimuth servo motor (131) fixed on the side wall of the base (15), and the output end of the azimuth servo motor (131) is connected to a gear (132) meshing with the outer ring (142) of the slewing bearing (14).

3. The large field of view optical calibration device according to claim 1, wherein On the side wall of the workbench (5) above the cross beam (16), three brackets (4) are evenly distributed along the circumferential direction, and a reference theodolite (3) is installed at the upper end of each of the three brackets (4).

4. A large field of view optical calibration device according to claim 1, characterized in that The lifting servo assembly (6) includes a lifting servo motor, and the output end of the lifting servo motor is connected to the upper end of the lead screw (7). The lead screw (7) is connected to the lifting bracket (8) through a lead screw nut. When the lead screw (7) rotates, it drives the lifting bracket (8) to move up and down along the guide rail (10) through the lead screw nut.

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