A method for marking the baseline of a film-type cargo containment system based on drones

Abstract

A method for marking the reference line of a film-type cargo containment system based on an unmanned aerial vehicle can quickly and accurately complete the marking construction work of the film-type containment system. According to the design drawing, the theoretical coordinate values ​​of 16 vertices, the theoretical lengths of 8 longitudinal edges, the theoretical coordinates of the reference axis loop line and the theoretical length of the liquid dome in the X direction are obtained. The actual coordinate values ​​of 16 vertices, the actual lengths of 8 longitudinal edges, the actual coordinates of the reference axis loop line and the actual length of the liquid dome in the X direction are obtained by using point cloud processing software. The difference between the actual measured value and the theoretical value of the cargo hold does not exceed the inspection length, and the optimal loop lines are selected for spraying. The cargo hold modeling method based on the unmanned aerial vehicle laser radar mapping technology of the present invention is more accurate, does not require the help of an installation platform, does not rely on GTT marking drawings and their software, can complete the marking work of the film hold, greatly reduces the manual construction work and the types of marking equipment and tools, improves the marking accuracy, and shortens the marking period.

Description

Technical Field

[0001] The invention belongs to the field of film type containment system design and construction, and in particular relates to a reference line marking method for a film type cargo containment system based on an unmanned aerial vehicle. Background Art

[0002] In the MARK membrane containment system, in order to ensure the installation accuracy of each insulating component and the primary and secondary screen walls, it is necessary to first draw the installation reference line inside the cargo hold after the hull bottom is formed and the installation platform (a special large scaffolding) is built. Figure 1 The figure shows the schematic diagram of the reference line and loop line in the cargo hold. Because the main screen wall is a corrugated plate with regular wrinkles and has continuity in the three directions of XYZ inside the cargo hold, the common practice in the industry is to measure the size of each side and the coordinate value of the vertex in the cargo hold through laser trackers and other equipment on the inner bottom of the hull and the cargo hold, and draw the center point of each side line on the deck, and then import the measurement data into the M3 software of the French GTT company for calculation. The software generates the ideal reference line coordinate value of each deck, and then draws the actual reference line inside the cargo hold based on the calculation results through laser rangefinders, laser levelers, ink fountains, tape measures and other tooling tools. A similar method has been published in patent number ZL 202011418423.7.

[0003] However, since the construction premise of this method is that the installation platform is completed, the construction period is affected by the construction progress of the installation platform. For a 175,000 m³ LNG carrier, there are 1 25,000 m³ and 3 50,000 m³ cargo holds, each of which is more than 30 meters high and 30-50 meters long. In order to complete the length measurement and marking of each plane inside such a large cargo hold, the installation platform is required to place the laser tracker and receiving device at each target point and complete the marking and marking of the corresponding edges.

[0004] Secondly, due to the influence of weld height and hull shape, the laser tracker receiver cannot be placed at the actual boundary, and the coordinates of each vertex cannot be directly measured. Instead, the deck is simulated by placing 4 to 6 laser tracker receivers near each edge, and the vertex coordinates are obtained through the intersection lines and intersection points formed by the software. This method cannot truly reflect the actual coordinate values ​​of each vertex and the length of each edge.

[0005] Thirdly, during the marking process, it is necessary to cooperate with the laser leveler, use the tape measure and marker pen to mark the bulkhead at intervals of about 2m, and then use the ink fountain to connect these marked points one by one to get the reference line. The construction process requires a large amount of manual work and a long construction period. The construction on the top surface and upper slope is difficult and the accuracy is difficult to control.

[0006] UAV surveying and spraying technology has been applied in agriculture, forestry, mining, infrastructure engineering and many other fields. At present, based on laser radar technology and perfect flight control system algorithm, it is possible to achieve precise positioning flight in a limited space, complete three-dimensional surveying and mapping work and form a real-time point cloud map. With the help of point cloud post-processing software such as Leica 3DR and Trimble, three-dimensional modeling, measurement, deformation analysis, and volume calculation can be completed. The three-dimensional model based on the point cloud is more accurate and reflects the actual three-dimensional coordinates of the measured object. UAVs equipped with spray cans can complete precise spraying work according to the specified flight path. If UAV surveying and spraying technology is introduced into the marking work of the film cargo containment system, the marking process can be advanced, the measurement accuracy can be improved, and the labor cost can be reduced. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a method for marking the baseline of a film-type cargo containment system based on an unmanned aerial vehicle, which aims to quickly and accurately complete the marking construction work of the film-type containment system. The technical solution adopted is:

[0008] S1. Obtain the theoretical values ​​of the cargo hold according to the design drawing. The theoretical coordinate values ​​of 16 vertices, the theoretical lengths of 8 longitudinal edges, and the coordinates of the reference axis loop line AN 3the , AN 2the , AN 1the , the length of the liquid dome in the X direction is D LDXthe .

[0009] S2. After the cargo hold is formed and the hull bottom paint is sprayed, a surveying drone suitable for limited space flight is placed in the hold. Before the drone takes off, the target area for measurement in the hold is configured and the overlap rate (60%-80%) is set. The drone autonomously generates a flight route and then takes off. After the aerial photography is completed, point cloud information is obtained.

[0010] S3. Import the point cloud information in the drone into the point cloud processing software (Leica 3DR and Trimble, etc.) to build a 3D model of the actual cargo hold.

[0011] S4. Obtain the actual coordinate values ​​of 16 vertices in the point cloud processing software, measure the actual lengths of the 8 longitudinal edges, find the midpoint position of each edge, and record the actual midpoint coordinate data.

[0012] S5. Check the difference between each measured value and the theoretical value of the cargo hold. If it exceeds the inspection length, recheck the input data. If it does not exceed the inspection length, proceed to the next step.

[0013] S6. Enter the actual midpoint coordinate data of the above sides into the flight control system of the spraying drone, take off the spraying drone, fly to the specified midpoint coordinate position, and spray the recorded midpoint position on the inner wall of the cargo hold.

[0014] S7. Based on the actual cargo hold measurement values, the optimal hold size is obtained by calculation, the optimal hold type is established, and the optimal reference axis loop line coordinates are obtained: AN 3cal , AN 2cal , AN 1cal In the optimal cabin type, the reference lines of each deck must be continuous and perpendicular to each other.

[0015] S8. Actual coordinates of the midpoints of the four sides perpendicular to the hull bottom and the optimal loop AN 1cal Four differences in coordinates in the Z direction M lcal (Z), find the optimal reference axis loop line in the solid 3D model AN 1cal The difference between any of the four sides l M lcal (Z) is M lcal (Z)= AN 1cal- AN 1the+ M lact (Z)-1 / 2[ A act (Z) -A the (Z)+( B act (Z) -B the (Z))].

[0016] in:

[0017] M lact (Z) is the actual coordinate Z value of the midpoint of side l;

[0018] A act (Z) is the actual coordinate Z value of vertex A at one end of edge l;

[0019] A the (Z) is the theoretical coordinate Z value of vertex A at one end of edge l;

[0020] B act (Z) is the actual coordinate Z value of vertex B at the other end of edge l;

[0021] B the(Z) is the theoretical coordinate Z value of vertex B at the other end of side l.

[0022] S9. Use a spraying drone to spray the optimal reference shaft ring line on the bottom surface of the cargo hold AN 1cal .

[0023] S10. Actual coordinates of the midpoints of the four sides parallel to the hull bottom and the optimal loop AN 2cal Four differences in the Y direction M lcal (Y), Find the optimal reference axis loop in the solid 3D model AN 2cal The difference between any of the four sides l M lcal (Y) is: M lcal (Y)= AN 2cal- AN 2the+ M lact (Y)-1 / 2[ A act (Y) -A the (Y)+( B act (Y) -B the (Y))].

[0024] in:

[0025] M lact (Y) is the actual Y coordinate value of the midpoint of side l;

[0026] A act (Y) is the actual coordinate Y value of vertex A at one end of edge l;

[0027] A the (Y) is the theoretical coordinate Y value of vertex A at one end of edge l;

[0028] B act (Y) is the actual Y coordinate value of vertex B at the other end of side l;

[0029] B the (Y) is the theoretical coordinate Y value of vertex B at the other end of side l.

[0030] S11. Adjust the optimal reference axis loop line based on the center line of the liquid dome AN2cal Get the adjustment reference axis circle line AN 2shi Because the main shield at the liquid dome has continuous corrugation with the main shield in the cargo hold, the reference axis ring line needs to be adjusted according to the Y axis centerline at the liquid dome. AN 2cal location.

[0031] S12. Use a spraying drone to spray and adjust the reference axis ring line on the bottom surface of the cargo hold AN 2shi .

[0032] S13. Actual coordinates and optimal loop lines based on the midpoints of the longitudinal eight-side lines of the top, bottom, port and starboard surfaces AN 3cal The difference of the coordinates in the X direction is used to obtain the optimal midpoint coordinate X value of each of the eight sides. M lcal (X), and then find the optimal reference axis loop line in the solid 3D model AN 3cal , the optimal midpoint coordinate X value of any edge l among the eight edges M lcal (X) is:

[0033] M lcal (X)= AN 3cal- AN 3the+ M lact (X)-1 / 2[ A act (X) -A the (X)+( B act (X) -B the (X))].

[0034] in:

[0035] M lact (X) is the actual coordinate X value of the midpoint of side l;

[0036] A act (X) is the actual coordinate X value of vertex A at one end of edge l;

[0037] A the (X) is the theoretical coordinate X value of vertex A at one end of edge l;

[0038] B act(X) is the actual coordinate X value of vertex B at the other end of side l;

[0039] B the (X) is the theoretical coordinate X value of vertex B at the other end of side l.

[0040] S14. Adjust the optimal reference axis loop line based on the liquid dome edge AN 3cal Get the adjustment reference axis circle line AN 3shi Also, because the main barrier wall at the cargo hold has continuity with the main barrier wall corrugation in the cargo hold, it is also necessary to calculate the liquid dome edge line LD M Adjusting the reference axis circle AN 3cal location.

[0041] S15. Use a spraying drone to spray and adjust the reference axis ring line on the bottom surface of the cargo hold AN 3shi .

[0042] S16. Find the optimal reference axis BR1 for the upper and lower inclined surfaces up , BR1 low In order to ensure that the corrugations of the upper and lower slopes are continuous with the corrugations of the B / D surface after the connection of the corner components and the corner connectors, it is necessary to determine the reference baseline RE on the B / D surface by calculation based on the optimal cabin data. up ,RE low , R.E. up ,RE low Relative to the optimal loop AN 1cal The difference Z up , Z low Right now:

[0043] Z up =170+340×[1 / 2(n3+n4)] round up;

[0044] Z low =170+340×[1 / 2(n1+n2)] round up;

[0045] n 1= [( AN 1cal - TH -170) / 340-1] round up;

[0046] n 2= [( AN1cal - H lowcal -170) / 340 / 2-1] round up;

[0047] n 3= [( H cal -AN 1cal - TH -170) / 340-1] round up;

[0048] n 4= [( H cal -AN 1cal - H upcal -170) / 340-1] and round up.

[0049] in:

[0050] TH It is the sum of the theoretical resin layer thickness and the theoretical insulation layer thickness;

[0051] H lowcal is the optimal lower slope height value;

[0052] H upcal is the optimal upper slope height value;

[0053] H cal is the optimal cargo hold height.

[0054] And the reference line RE up , R.E. low Based on the actual length of the hypotenuse, through RE up , R.E. low With BR1 up , BR1 low The correlation formula in the Z direction is used to obtain RE up , R.E. low With BR1 up , BR1 low The Z coordinate difference Z BR1up , Z BR1low ,Right now: Z BR1up = H cal -AN 1cal - Z up-l upact sinα; Z BR1low = AN 1cal - Z low -l lowact sinα .

[0055] in:

[0056] l upact is the actual length of any upper hypotenuse;

[0057] l lowact is the actual length of any lower hypotenuse;

[0058] α is the acute angle between the hypotenuse and the base;

[0059] Finally, the slope reference axis BR1 is found in the 3D model through the difference up , BR1 low；

[0060] S17. Use a spraying drone to spray the upper and lower slopes on the bottom surface of the cargo hold with the optimal reference axis BR1 up , BR1 low；

[0061] S18. The drone mission is completed and the baseline marking of the film cargo containment system is completed.

[0062] The beneficial effects of the present invention are:

[0063] 1. The cargo hold modeling method based on UAV lidar mapping technology is more accurate, reflecting the actual three-dimensional coordinates of the cargo hold and providing a data basis for subsequent cargo hold flatness measurement.

[0064] 2. Drone-based marking work can advance this process without the help of an installation platform. At the same time, it greatly reduces manual construction work and the types of marking equipment and tools, improves marking accuracy, and shortens marking construction period. The construction period for each deck is adjusted from approximately 2-3 days / 12 people to 2-3 days / 5 people per deck.

[0065] 3. This marking method can express the coordinates of each reference line and loop line through a formula, and can complete the marking of membrane tanks without relying on GTT marking drawings and software. It realizes the independent innovation and efficient application of this technology, greatly improves the level of autonomy, and brings new breakthroughs in the field of membrane tank marking. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figures 1 - 7 , Figure 10 It is a schematic diagram of the operation process;

[0067] Figure 8 yes Figure 7 A is an enlarged schematic diagram;

[0068] Figure 9 yes Figure 7 A magnified schematic diagram of B. DETAILED DESCRIPTION

[0069] The present invention will be further described in conjunction with the accompanying drawings.

[0070] S1. Obtain the theoretical values ​​of the cargo hold according to the design drawing. The theoretical coordinate values ​​of the 16 vertices , , , , , , , , , , , ), , , , Theoretical lengths of the 8 longitudinal sides: , , , , , , , Theoretical lengths of the 16 horizontal sides: , , , , , , , , , , , , , , , . Datum axis loop line coordinates: , 0, , the length of the liquid dome in the X direction is .

[0071] S2. After the cargo hold is formed and the hull bottom paint is sprayed, a surveying drone suitable for limited space flight is placed in the hold. Before the drone takes off, the target area for measurement in the hold is configured and the overlap rate is set to 80%. The drone autonomously generates a flight route and then chooses to take off. After the aerial photography is completed, point cloud information is obtained.

[0072] S3. Import the point cloud information in the drone into the point cloud processing software (Leica 3DR and Trimble, etc.) to build a 3D model of the actual cargo hold. The 3D coordinate origin is set as follows: Figure 2 shown.

[0073] S4. Obtain the actual coordinate values ​​of 16 vertices in the point cloud processing software , , , , , , , , , , , ), , , , . Measure the actual lengths of the 8 longitudinal sides: , , , , , , , and the actual lengths of the 16 horizontal sides , , , , , , , , , , , , , , , . Find the midpoint of each side and record the midpoint coordinates , , , , , , , , , , , , , , , , , , , , , , , .

[0074] S5. Check the difference between each measured value and the theoretical value of the cargo hold. If it exceeds the inspection length, recheck the input data. If it does not exceed the inspection length, proceed to the next step.

[0075] S6. Enter the actual midpoint coordinate data of the above sides into the flight control system of the spraying drone, take off the spraying drone, fly to the specified midpoint coordinate position, and spray the recorded midpoint position on the inner wall of the cargo hold.

[0076] S7. Establish the optimal cabin type based on the actual cargo hold. Because there is a size deviation between the actual cabin type and the theoretical cabin type, in order to draw a reference line inside the actual cargo hold, it is necessary to establish the optimal cabin size through calculation based on the actual measurement value. In addition, the reference lines of each deck in the optimal cabin type must be continuous and perpendicular to each other, such as Figure 2 , 3 As shown, the optimal cabin size is defined as follows:

[0077]

[0078]

[0079]

[0080]

[0081] =

[0082] =

[0083] =

[0084] =

[0085] Optimal reference axis loop coordinates: , 0,

[0086] S8. Find the optimal reference axis loop line in the solid 3D model based on the actual midpoint position of each side , see Figure 4 .

[0087] Optimal reference axis loop Intersects with DF, DJ, BJ, and BF at , , , .

[0088] In the F side,

[0089]

[0090]

[0091] In the J side,

[0092]

[0093]

[0094] In the actual 3D model of the cargo hold, according to the calculated Z-direction offset values ​​of the midpoints of the four sides DF, DJ, BJ, and BF , , , Get the corresponding coordinate value after offset , , , .

[0095] S9. Use a spraying drone to spray the optimal reference shaft ring line on the bottom surface of the cargo hold Set the flight path of the drone for line drawing so that the drone passes through the above four points. , , , Start spraying at any point, the path passes through the other three points, and the two adjacent points are connected by a straight line. After the setting is completed, the drone takes off and completes the optimal reference axis loop line Apply painting.

[0096] S10. Find the optimal reference axis loop line in the solid 3D model based on the actual midpoint position of each side , line see Figure 5 .

[0097] Optimal reference collar Intersects with DA, BA, BC, and DC at , , , .

[0098] In side A,

[0099]

[0100]

[0101] In the C side,

[0102]

[0103]

[0104] In the actual 3D model of the cargo hold, the Y-direction offset values ​​of the midpoints of the four sides DA, BA, BC, and DC are calculated. , , , Get the corresponding coordinate value after offset , , , .

[0105] S11. Adjust the optimal reference axis loop line based on the center line of the liquid dome Get the adjustment reference axis circle line Because the main shield at the liquid dome has continuous corrugation with the main shield in the cargo hold, the reference axis ring line needs to be adjusted according to the Y axis centerline at the liquid dome. First, locate the Y-axis centerline of the liquid dome in the actual 3D model of the cargo hold. , and extend the center line to the BC side to intersect Point, record and The difference in the Y direction Then according to the difference right , , The points are adjusted accordingly and the adjustment points are located in the 3D model. , , .

[0106] S12. Use a spraying drone to spray and adjust the reference axis ring line on the bottom surface of the cargo hold Set the flight path of the drone for line drawing so that the drone passes through the four points mentioned in S11 , , , Start spraying at any point, the path passes through the other three points, and the two adjacent points are connected by a straight line. After the setting is completed, the drone takes off and completes the reference axis loop line Apply painting.

[0107] S13. Find the optimal reference axis loop line in the solid 3D model based on the actual midpoint position of each side , see Figure 6 Optimal reference axis loop Intersects with AE, EF, FG, GC, CK, KJ, HJ, and HA at , , , , , , , .

[0108] The same method as S8 and S10 is used to calculate the A, F, C, and J surfaces respectively. , , , , , , , The calculated X-direction offset values ​​of the midpoints of the eight sides AE, EF, FG, GC, CK, KJ, HJ, and HA are used in the actual three-dimensional model of the cargo hold. , , , , , , , , get the corresponding coordinate value after offset , , , , , , , .

[0109] S14. Adjust the optimal reference axis loop line based on the liquid dome edge Get the adjustment reference axis circle line Also, because the main barrier wall at the cargo hold has continuity with the main barrier wall corrugation in the cargo hold, it is also necessary to follow the edge line of the liquid dome. Adjusting the reference axis circle location.

[0110] The intersection line between the liquid dome and the A surface in the actual 3D model of the cargo hold ,by is the midpoint, Take any equal distance on both sides and record the coordinate values , , measured on the A surface , To the Loop Line Distance and ,but The adjustment value in the X direction is - Then adjust the value right , , , , , , , The eight vertices are adjusted accordingly and the adjustment points are located in the 3D model. , , , , , , , .

[0111] S15. Use a spraying drone to spray the bottom surface of the cargo hold to adjust the reference shaft ring line Set the flight path of the drone to make the drone pass through the eight vertices mentioned in S14 , , , , , , , Start spraying at any point, the path passes through the other seven points, and the two adjacent points are connected by a straight line. After the setting is completed, the drone takes off and completes the reference axis loop line Apply painting.

[0112] S16. Find the optimal reference axis of the upper and lower inclined surfaces , ,like Figure 7 To ensure that the corrugations of the upper and lower slopes are continuous with the corrugations of the B / D surface after the connection of the corner components and the corner connectors, it is necessary to use the B / D surface reference line RE up , R.E. low The reference axis of the inclined plane , .

[0113] For 2 / 3 / 4 / cabins, the upper and lower bevel angles are , let TH = theoretical resin layer thickness + theoretical insulation layer thickness, for MARK III FLEX type membrane cabin, TH = 12.5 + 400 = 412.5mm.

[0114] , . , .

[0115] The reference axis RE up , R.E. low Distance to optimal reference axis loop The distance is:

[0116] .

[0117] .

[0118] in addition,

[0119] .

[0120] .

[0121] According to and The values ​​of are used to locate the optimal reference axis in the three-dimensional solid model. , Intersection value with upper and lower oblique edges , , , , , , , .

[0122] S17. Use a spraying drone to spray the upper and lower slopes on the bottom surface of the cargo hold to achieve the optimal reference axis , ,like Figure 10 Set the flight path of the drone for line drawing so that the drone paths are connected in straight lines. and , and , and , and After the setting is completed, the drone takes off and completes the optimal reference axis of the upper and lower slopes , Apply painting.

[0123] S18. The drone mission is completed and the baseline marking of the film cargo containment system is completed.

Claims

1. A method for marking a reference line of a film-type cargo containment system based on an unmanned aerial vehicle, characterized in that: The specific operations are as follows: S1. Obtain the theoretical values ​​of the cargo hold according to the design drawing: the theoretical coordinate values ​​of 16 vertices, the theoretical lengths of 8 longitudinal edges, the coordinates of the reference axis loop AN 3the , AN 2the , AN 1the , the length of the liquid dome in the X direction is D LDXthe ; S2. After the cargo hold is formed and the hull bottom is painted, a surveying drone suitable for limited space flight is placed in the hold. Before the drone takes off, the target area to be measured in the hold is configured and the overlap rate is set. The drone autonomously generates a flight route and then takes off. After the aerial photography is completed, point cloud information is obtained; S3. Import the point cloud information in the drone into the point cloud processing software to build a three-dimensional model of the actual cargo hold; S4. Obtain the actual coordinate values ​​of 16 vertices in the point cloud processing software, measure the actual lengths of the 8 longitudinal edges, find the midpoint position of each edge, and record the actual midpoint coordinate data; S5. Check the difference between each measured value and the theoretical value of the cargo hold. If it exceeds the inspection length, recheck the input data. If it does not exceed the inspection length, proceed to the next step; S6. Enter the actual midpoint coordinate data of the above sides into the flight control system of the spraying drone, and the spraying drone takes off, flies to the designated midpoint coordinate position, and sprays the recorded midpoint position on the inner wall of the cargo hold; S7. Based on the actual cargo hold measurement values, the optimal hold size is obtained by calculation, the optimal hold type is established, and the optimal reference axis loop line coordinates are obtained: AN 3cal , AN 2cal , AN 1cal , in the optimal cabin type, the reference lines of each deck must be continuous and perpendicular to each other; S8. Actual coordinates of the midpoints of the four sides perpendicular to the hull bottom and the optimal loop AN 1cal The difference of coordinates in the Z direction is used to obtain the optimal midpoint coordinate Z value of each of the four sides. M lcal (Z), and then find the optimal reference axis loop line in the solid 3D model AN 1cal， The optimal midpoint coordinate Z value of any side l among the four sides M lcal (Z) is: M lcal (From)= AN 1cal - AN 1the + M lact (Z)-1 / 2[ A act (WITH) -A the (From)+( B act (WITH) -B the (WITH))]; in: M lact (Z) is the actual coordinate Z value of the midpoint of side l; A act (Z) is the actual coordinate Z value of vertex A at one end of edge l; A the (Z) is the theoretical coordinate Z value of vertex A at one end of edge l; B act (Z) is the actual coordinate Z value of vertex B at the other end of edge l; B the (Z) is the theoretical coordinate Z value of vertex B at the other end of side l; S9. Use a spraying drone to spray the optimal reference shaft ring line on the bottom surface of the cargo hold AN 1cal ; S10. Actual coordinates of the midpoints of the four sides parallel to the hull bottom and the optimal loop AN 2cal The four differences of the coordinates in the Y direction are used to obtain the optimal midpoint coordinate Y values ​​of the four sides. M lcal (Y), and then find the optimal reference axis loop line in the solid 3D model AN 2cal， The optimal midpoint coordinate Y value of any side l among the four sides M lcal (Y) is: M lcal (Y)= AN 2cal - AN 2the + M lact (Y)-1 / 2[ A act (AND) -A the (Y)+( B act (AND) -B the (AND))]; in: M lact (Y) is the actual Y coordinate value of the midpoint of side l; A act (Y) is the actual coordinate Y value of vertex A at one end of edge l; A the (Y) is the theoretical coordinate Y value of vertex A at one end of edge l; B act (Y) is the actual Y coordinate value of vertex B at the other end of side l; B the (Y) is the theoretical coordinate Y value of vertex B at the other end of side l; S11. Adjust the optimal reference axis loop line based on the center line of the liquid dome AN 2cal Get the adjustment reference axis circle line AN 2shi ; S12. Use a spraying drone to spray and adjust the reference axis ring line on the bottom surface of the cargo hold AN 2shi ; S13. Actual coordinates and optimal loop lines based on the midpoints of the longitudinal eight-side lines of the top, bottom, port and starboard surfaces AN 3cal The difference of the coordinates in the X direction is used to obtain the optimal midpoint coordinate X value of each of the eight sides. M lcal (X), and then find the optimal reference axis loop line in the solid 3D model AN 3cal， The optimal midpoint coordinate X value of any edge l among the eight edges M lcal (X) is: M lcal (X)= AN 3cal - AN 3the + M lact (X)-1 / 2[ A act (X) -A the (X)+( B act (X) -B the (X))]; in: M lact (X) is the actual coordinate X value of the midpoint of side l; A act (X) is the actual coordinate X value of vertex A at one end of edge l; A the (X) is the theoretical coordinate X value of vertex A at one end of edge l; B act (X) is the actual coordinate X value of vertex B at the other end of side l; B the (X) is the theoretical coordinate X value of vertex B at the other end of side l; S14. Adjust the optimal reference axis loop line based on the liquid dome edge AN 3cal Get the adjustment reference axis circle line AN 3shi ; S15. Use a spraying drone to spray and adjust the reference axis ring line on the bottom surface of the cargo hold AN 3shi ; S16. Find the optimal reference axis BR1 for the upper and lower inclined surfaces up , BR1 low In order to ensure that the corrugations of the upper and lower slopes are continuous with the corrugations of the B / D surface after the connection of the corner components and the corner connectors, it is necessary to determine the reference baseline RE on the B / D surface by calculation based on the optimal cabin data. up ,RE low , R.E. up ,RE low Relative to the optimal loop AN 1cal The difference Z up , Z low Right now: Z up =170+340×[1 / 2(n3+n4)] round up; Z low =170+340×[1 / 2(n1+n2)] round up; n 1= [( AN 1cal - TH -170) / 340-1] round up; n 2= [( AN 1cal - H lowcal -170) / 340 / 2-1] round up; n 3= [( H cal -AN 1cal - TH -170) / 340-1] round up; n 4= [( H cal -AN 1cal - H upcal -170) / 340-1] round up; in: TH It is the sum of the theoretical resin layer thickness and the theoretical insulation layer thickness; H lowcal is the optimal downslope height value; H upcal is the optimal upper slope height value; H upcal is the optimal upper slope height value; H cal is the optimal cargo hold height value; And the reference line RE up , R.E. low Based on the actual length of the hypotenuse, through RE up , R.E. low With BR1 up , BR1 low The correlation formula in the Z direction is used to obtain RE up , R.E. low With BR1 up , BR1 low The Z coordinate difference Z BR1up , Z BR1low ,Right now: Z BR1up = H cal -AN 1cal - Z up -l upact sinα; Z BR1low = AN 1cal -Z low -l lowact sinα; in, l upact is the actual length of any upper hypotenuse; l lowact is the actual length of any lower hypotenuse; α is the acute angle between the hypotenuse and the base; Finally, the slope reference axis BR1 is found in the 3D model through the difference up , BR1 low ; S17. Use a spraying drone to spray the upper and lower slopes on the bottom surface of the cargo hold with the optimal reference axis BR1 up， BR1 low ; S18. The drone mission is completed and the baseline marking of the film cargo containment system is completed.

2. A method for marking a reference line of a film-type cargo containment system based on an unmanned aerial vehicle according to claim 1, characterized in that: In step S2, the overlap rate is 60%-80%.

3. The method for marking a reference line of a film-type cargo containment system based on an unmanned aerial vehicle according to claim 1, characterized in that: In step S3, the point cloud processing software is Leica 3DR and Trimble.

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