Large-span spherical reflecting surface inspection method

Abstract

The invention discloses a large-span spherical reflecting surface inspection method, belongs to the technical field of large-span spherical reflecting surface maintenance, and solves the technical problem of low efficiency of an existing inspection and maintenance method. The method comprises the steps of formulating a detection climbing path according to the height of a node disc; when the reflecting surface is in a spherical state, randomly sampling at least two adjacent reflecting surface units; the maintainer climbs to the reflecting surface unit according to the climbing path; performing anti-corrosion inspection on a circular seam of a main cable of the cable net structure at the reflecting surface unit, and inspecting the reflecting surface unit according to a set inspection outline; when the anti-corrosion inspection is not qualified, corresponding anti-corrosion measures are taken for the circular seam of the main cable of the cable net structure, and the specific anti-corrosion measures and the construction date are recorded; and when the reflecting surface unit is inspected to be unqualified, corresponding maintenance measures are taken on the reflecting surface unit, and specific maintenance measures and construction dates are recorded. Work can be carried out on the premise that normal observation of the large-span spherical reflecting surface is not affected, and efficiency is high.

Description

Technical Field

[0001] The invention relates to the technical field of maintenance of a large-span spherical reflective surface, and more specifically, to an inspection method for a large-span spherical reflective surface. Background Art

[0002] During the detection process, FAST (radio telescope) will adjust the position and shape of each FAST reflector unit according to the detection direction. In the long-term operation process, adjacent reflector units may be damaged by collision, and the unit connection mechanism may be stuck when the reflector is displaced, causing the back frame rods to deform, which will affect the detection accuracy of the radio telescope.

[0003] At present, the method for inspecting the FAST reflector unit is that maintenance personnel use microgravity spiders to go to the reflector unit for inspection and maintenance, such as a giant radio telescope reflector inspection and maintenance method disclosed in patent CN110931984B.

[0004] However, the preparation work for the microgravity Spider-Man (including inflation, moving to the reflective surface unit via a cableway, etc.) takes a long time (much more than 1 hour) and is inefficient. Summary of the invention

[0005] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art, and an object of the present invention is to provide a large-span spherical reflective surface inspection method that can improve efficiency.

[0006] The technical solution of the present invention is: a large-span spherical reflective surface inspection method, comprising the following steps:

[0007] Step 1. According to the height of the node disk, a climbing path for maintenance personnel to reach the node disk is formulated to meet the requirement of arriving and being ready within 1 hour;

[0008] Step 2. When the reflective surface is in a spherical state, the maintenance personnel conduct an on-site inspection and randomly select at least two adjacent reflective surface units on-site;

[0009] Step 3. The maintenance personnel climbs to the reflecting surface unit according to the climbing path corresponding to the node disk where the reflecting surface unit is located;

[0010] Step 4. The maintenance personnel conduct an anti-corrosion inspection on the annular seam of the main cable of the cable net structure at the reflecting surface unit and keep records; inspect the reflecting surface unit according to the set inspection outline and keep records;

[0011] Step 5. When the anti-corrosion inspection fails, corresponding anti-corrosion measures are taken on the annular seam of the main cable of the cable net structure, and the specific anti-corrosion measures and construction date are recorded; when the reflection surface unit inspection fails, corresponding maintenance measures are taken on the reflection surface unit, and the specific maintenance measures and construction date are recorded.

[0012] As a further improvement, the following steps are also included:

[0013] Step 6. When the reflective surface is actively deformed, the maintenance personnel conduct an on-site inspection and randomly select at least 5 node disks on site;

[0014] Step 7. The maintenance personnel climb to the node disk according to the climbing path corresponding to the node disk to be inspected;

[0015] Step 8. The maintenance personnel inspect the connection mechanism of the node disk to be inspected according to the inspection outline and make records;

[0016] Step 9. When the connection mechanism fails the inspection, after the reflective surface of the connection mechanism area is in a spherical state, corresponding maintenance measures are taken on the connection mechanism, and the specific maintenance measures and construction date are recorded.

[0017] Furthermore, the climbing path includes:

[0018] When the height of the node plate is not more than 10m, the maintenance personnel can directly reach the node plate by climbing the ladder;

[0019] When the height of the node plate is greater than 10m, the maintenance personnel pass through the ring beam and climb along the main cables of the cable net structure to reach the node plate; or, the maintenance personnel first reach the adjacent node plate with a height not exceeding 10m by climbing a ladder, and then climb along the main cables of the cable net structure to the node plate with a height greater than 10m.

[0020] Furthermore, in step 2, a spherical area in a spherical state is determined according to the observation trajectory of the large-span spherical reflective surface, and at least two adjacent reflective surface units are randomly sampled in the spherical area.

[0021] Furthermore, in step 3, after the maintenance personnel climb to the reflective surface unit, they cooperate with the ground staff to install a simple lightweight hanging basket to facilitate maintenance work.

[0022] Furthermore, the inspection outline includes:

[0023] Check that there is no collision or damage between adjacent reflective surface units;

[0024] Check that the panels of the reflective surface unit form a complete plane without any unevenness, and that there is no obvious height difference between the panels of two adjacent reflective surface units;

[0025] The gap width between two adjacent reflector units is measured to be within the range of 65±15mm, and the telescopic length of the axial end point of the connection mechanism of the reflector unit in the direction of the center of the node disk is within the range of 60±10mm;

[0026] The end point axis of the connecting mechanism of the measuring reflective surface unit is in the middle position of the gantry without obvious deviation.

[0027] Furthermore, after the maintenance personnel arrive at the node disk, they open a panel of the reflective surface unit and inspect the reflective surface unit.

[0028] Furthermore, in step 6, the deformation area of ​​the reflective surface where the reflective surface is actively deformed is determined according to the observation trajectory of the large-span spherical reflective surface, and at least 5 node disks are randomly sampled in the deformation area.

[0029] Furthermore, the inspection outline also includes: visually and auditorily checking that when the reflective surface is displaced, the connecting mechanism of the reflective surface unit is well lubricated, there is no sticking, and the back frame rods are not deformed.

[0030] Furthermore, a large model is established based on the recorded data for big data analysis, and then combined with the comprehensive data of manual inspection or drone inspection, the development trend of the data is analyzed through the large model to predict the time of the next inspection.

[0031] Beneficial Effects

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] The present invention formulates different climbing paths according to node disks of different heights, so that maintenance personnel can meet the requirements of arriving and being prepared within 1 hour, and carry out inspection work without affecting the normal observation of the large-span spherical reflection surface. Compared with the current method of relying on microgravity spiders, the present invention is more efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a flow chart of the present invention;

[0035] Figure 2 This is a schematic diagram of the detection of a large-span spherical reflective surface;

[0036] Figure 3 It is a top view of a long-span spherical reflector;

[0037] Figure 4 for Figure 3 A schematic diagram of the structure of adjacent reflective surface units at A in the middle;

[0038] Figure 5 for Figure 4 Schematic diagram of the node disk structure at B in the middle;

[0039] Figure 6 is a schematic structural diagram of a reflective surface unit and a connecting mechanism;

[0040] Figure 7 This is a sampling order diagram of the gap width between adjacent reflective surface units.

[0041] Among them: 1-node plate, 2-reflection surface unit, 3-main cable of cable net structure, 4-connecting mechanism, 5-cable net, 6-ring beam, 7-pull-down cable, 8-actuator, 9-deformation area, 10-spherical area, 11-feed cabin. DETAILED DESCRIPTION

[0042] The present invention will be further described below with reference to the specific embodiments in the accompanying drawings.

[0043] The Fivehundred-meter Aperture Spherical radio Telescope (FAST), built by the National Astronomical Observatory of the Chinese Academy of Sciences, is the world's largest single-aperture radio telescope. It breaks through the 100-meter engineering limit of ground-based telescopes and creates a new model for building giant radio telescopes. The overall technical indicators of FAST are: aperture of 500m, curvature radius of the reflecting surface of 300m; illumination area aperture of 300m, focal ratio f / D = 0.467.

[0044] The FAST active reflector is mainly composed of a ring beam, a reflector, a cable net, an actuator, and a ground anchor. Figure 2-Figure 6 As shown, the cable net 5 is composed of a main cable 3 of the cable net structure, which is installed on a ring beam 6. The cable net 5 has 2225 node disks 1. About 4450 reflector units 2 are installed on the node disks 1 of the cable net 5 to form a reflector. A pull-down cable 7 and an actuator 8 are connected below each node disk 1, and the actuator 8 is connected to the ground anchor. By controlling the actuator 8, a 300-meter-diameter instantaneous parabola is realized for astronomical observation. When not observing, the entire FAST is in a spherical state. During observation, the area where the reflector actively deforms into a parabola is the deformation area 9 (i.e., the 300-meter-diameter instantaneous parabola), and the rest is the non-observation spherical area 10. The feed cabin 11 will move to the upper side corresponding to the deformation area 9 to receive signals.

[0045] like Figure 1 As shown, the present invention provides a large-span spherical reflective surface inspection method, comprising the following steps:

[0046] Step 1. According to the height of the node disk 1, a climbing path for maintenance personnel to reach the node disk 1 is formulated to meet the requirement of arriving and being ready within 1 hour;

[0047] Step 2. When the reflective surface is in a spherical state, the maintenance personnel conduct an on-site inspection and randomly select at least two adjacent reflective surface units 2 on-site;

[0048] Step 3. The maintenance personnel climbs to the reflector unit 2 according to the climbing path corresponding to the node disk 1 where the reflector unit 2 is located;

[0049] Step 4. The maintenance personnel conduct an anti-corrosion inspection on the annular seam of the main cable 3 of the cable net structure at the reflective surface unit 2 and keep records; inspect the reflective surface unit 2 according to the set inspection outline and keep records;

[0050] Step 5. If the anti-corrosion inspection fails, take corresponding anti-corrosion measures on the annular seam of the main cable 3 of the cable net structure, and record the specific anti-corrosion measures and construction date. It is convenient to judge which anti-corrosion measure has better anti-corrosion performance according to the recorded construction date; if the reflection surface unit 2 fails the inspection, take corresponding maintenance measures on the reflection surface unit 2, and record the specific maintenance measures and construction date. The above is a static inspection of the large-span spherical reflection surface.

[0051] Furthermore, the method further comprises the following steps:

[0052] Step 6. When the reflective surface is actively deformed, the maintenance personnel conduct an on-site inspection and randomly select at least 5 node disks 1 on site;

[0053] Step 7. The maintenance personnel climb to the node disk 1 according to the climbing path corresponding to the node disk 1 sampled for inspection;

[0054] Step 8. The maintenance personnel inspect the connection mechanism 4 of the node disk 1 to be inspected according to the inspection outline and make records;

[0055] Step 9. When the connection mechanism 4 fails the inspection, after the reflective surface in the area of ​​the connection mechanism 4 is in a spherical state, the connection mechanism 4 is repaired accordingly, and the specific repair measures and construction date are recorded. The above is a dynamic inspection of a large-span spherical reflective surface.

[0056] Climbing trails include:

[0057] When the height of the node disk 1 is not greater than 10m, the maintenance personnel can directly reach the node disk 1 by climbing the ladder;

[0058] When the height of the node plate 1 is greater than 10m, the maintenance personnel pass through the ring beam and climb along the main cable 3 of the cable net structure to reach the node plate 1; or, the maintenance personnel first reach the adjacent node plate 1 with a height not greater than 10m by climbing the ladder, and then climb along the main cable 3 of the cable net structure to the node plate 1 with a height greater than 10m. The purpose is to minimize the time spent by the maintenance personnel to reach the node plate 1 under the premise of ensuring safety.

[0059] In this embodiment, two node disks were randomly checked. The first node disk is numbered E006, which is lower from the ground, about 4 meters. Maintenance personnel can bring themselves and the equipment to the vicinity of the node disk by climbing a ladder, and the time required is measured to be about 4 minutes and 25 seconds. The second node disk is numbered B224, which is higher from the ground, about 30 meters. Maintenance personnel need to slide along the cable net from the edge of the ring beam to the vicinity of the designated node disk. The straight-line distance is visually about 90 meters, and then release the rope from the node disk to lift the equipment up. The time required is measured to be about 48 minutes and 35 seconds. All meet the requirements of arriving and being ready within 1 hour.

[0060] In step 2, the spherical area in the spherical state is determined according to the observation trajectory of the large-span spherical reflector, and at least two adjacent reflector units 2 are randomly sampled in the spherical area. In step 6, the deformation area of ​​the reflector actively deformed is determined according to the observation trajectory of the large-span spherical reflector, and at least five node disks 1 are randomly sampled in the deformation area.

[0061] In step 3, after the maintenance personnel climb to the reflector unit 2, they cooperate with the ground staff to install a simple lightweight hanging basket to facilitate maintenance work. That is, after the maintenance personnel reach the node disk, they lower the hanging rope, and the ground staff cooperate to hang the lightweight hanging basket to the node disk for installation. The maintenance personnel can enter the lightweight hanging basket for maintenance to improve safety and convenience.

[0062] After the maintenance personnel arrive at the node disk 1 , they open a panel of the reflection surface unit 2 and extend their body to the top of the reflection surface unit 2 to inspect the reflection surface unit 2 .

[0063] The inspection outline includes:

[0064] (1) Check that there is no collision or damage between adjacent reflective surface units 2; this is mainly done by visual inspection by maintenance personnel;

[0065] (2) Check that the panels of the reflective surface unit 2 form a complete plane without any unevenness, and that there is no obvious height difference between the panels of two adjacent reflective surface units 2; this can be done by using a ruler or a test board to check the surface;

[0066] (3) The gap width between two adjacent reflective surface units 2 measured by a ruler is within the range of 65 ± 15 mm, and the telescopic length of the connecting mechanism end point (i.e., the 1# connecting mechanism end point) of the reflective surface unit 2 in the axial direction of the center of the node disk 1 is within the range of 60 ± 10 mm;

[0067] (4) Use a ruler to measure the axis of the end point of the connection mechanism of the reflective surface unit 2 (i.e., the end point of the 2# connection mechanism) in the middle of the gantry, and there is no obvious deviation;

[0068] (5) Visually and auditorily check that the connection mechanism 4 of the reflective surface unit 2 is well lubricated, without sticking, and the back frame rods are not deformed when the reflective surface is displaced. This item is a dynamic inspection for large-span spherical reflective surfaces.

[0069] The sampling order of the gap width between adjacent reflective surface units 2 is as follows: Figure 7 As shown in the figure, the seam width and height difference measurement method uses a steel ruler and a level to measure, and the statistics are shown in Table 1.

[0070] Table 1 Record of gap width of reflective surface unit

[0071]

[0072] Furthermore, a large model can be established based on the recorded data for big data analysis, and then combined with the comprehensive data of manual inspections or drone inspections, the development trend of the data can be analyzed through the large model to predict the time of the next inspection, so as to ensure the stability and accuracy of the large-span spherical reflector.

[0073] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A method for inspecting a large-span spherical reflective surface, characterized in that: The following steps are involved: Step 1. According to the height of the node disk (1), a climbing path for maintenance personnel to reach the node disk (1) is formulated to meet the requirement of arriving and being ready within 1 hour; Step 2. When the reflective surface is in a spherical state, the maintenance personnel conduct an on-site inspection and randomly select at least two adjacent reflective surface units (2) on-site; Step 3. The maintenance personnel climb to the reflecting surface unit (2) according to the climbing path corresponding to the node disk (1) where the reflecting surface unit (2) is located; Step 4. The maintenance personnel conduct an anti-corrosion inspection on the annular seam of the main cable (3) of the cable net structure at the reflecting surface unit (2), and keep a record; the reflecting surface unit (2) is inspected according to the set inspection outline, and a record is kept; Step 5. When the anti-corrosion inspection fails, corresponding anti-corrosion measures are taken on the annular seam of the main cable (3) of the cable net structure, and the specific anti-corrosion measures and construction dates are recorded; when the reflection surface unit (2) fails the inspection, corresponding maintenance measures are taken on the reflection surface unit (2), and the specific maintenance measures and construction dates are recorded.

2. A large-span spherical reflective surface inspection method according to claim 1, characterized in that: The following steps are also included: Step 6. When the reflective surface is actively deformed, the maintenance personnel conduct an on-site inspection and randomly select at least 5 node disks (1) on site; Step 7. The maintenance personnel climb to the node disk (1) according to the climbing path corresponding to the node disk (1) to be inspected; Step 8. The maintenance personnel inspect the connection mechanism (4) of the node disk (1) to be inspected according to the inspection outline and keep records; Step 9. When the connection mechanism (4) fails the inspection, after the reflective surface of the connection mechanism (4) is in a spherical state, corresponding maintenance measures are taken on the connection mechanism (4), and the specific maintenance measures and construction date are recorded.

3. A large-span spherical reflective surface inspection method according to claim 1, characterized in that: The climbing path includes: When the height of the node plate (1) is not greater than 10 m, the maintenance personnel can directly reach the node plate (1) by climbing a ladder; When the height of the node plate (1) is greater than 10 m, the maintenance personnel pass through the ring beam and climb along the main cable (3) of the cable net structure to reach the node plate (1); or, the maintenance personnel first use a ladder to reach an adjacent node plate (1) with a height not greater than 10 m, and then climb along the main cable (3) of the cable net structure to reach the node plate (1) with a height greater than 10 m.

4. A large-span spherical reflective surface inspection method according to claim 1, characterized in that: In step 2, a spherical area in a spherical state is determined according to the observation trajectory of the large-span spherical reflective surface, and at least two adjacent reflective surface units (2) are randomly sampled in the spherical area.

5. A large-span spherical reflective surface inspection method according to claim 1, characterized in that: In step 3, after the maintenance personnel climb up to the reflective surface unit (2), they cooperate with the ground staff to install a simple lightweight hanging basket to facilitate maintenance work.

6. A large-span spherical reflective surface inspection method according to claim 1, characterized in that: The inspection outline includes: Check that there is no collision or damage between adjacent reflective surface units (2); Check that the panels of the reflective surface unit (2) form a complete plane without any unevenness, and that there is no obvious height difference between the panels of two adjacent reflective surface units (2); The gap width between two adjacent reflective surface units (2) is measured to be within the range of 65 ± 15 mm, and the telescopic length of the axial end point of the connection mechanism of the reflective surface unit (2) in the direction of the center of the node disk (1) is within the range of 60 ± 10 mm; The end point axis of the connection mechanism of the measuring reflective surface unit (2) is located in the middle of the door frame without obvious deviation.

7. A large-span spherical reflective surface inspection method according to claim 1, characterized in that: After the maintenance personnel arrive at the node disk (1), they open a panel of the reflection surface unit (2) and inspect the reflection surface unit (2).

8. A large-span spherical reflective surface inspection method according to claim 2, characterized in that: In step 6, the deformation area of ​​the reflector surface where the reflector surface is actively deformed is determined according to the observation trajectory of the large-span spherical reflector surface, and at least 5 node disks (1) are randomly sampled in the deformation area.

9. A large-span spherical reflective surface inspection method according to claim 2, characterized in that: The inspection outline also includes: visually and auditorily checking that the connection mechanism (4) of the reflective surface unit (2) is well lubricated and free of sticking when the reflective surface is displaced, and that the back frame rod is not deformed.

10. A large-span spherical reflective surface inspection method according to claim 2, characterized in that: A large model is established based on the recorded data for big data analysis. Subsequently, the comprehensive data of manual inspection or drone inspection is combined, and the development trend of the data is analyzed through the large model to predict the time of the next inspection.

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