Combined high-altitude balloon and control method

Abstract

The combined high-altitude balloon comprises an anchoring balloon and a heavy-load balloon, and the anchoring balloon is pulled to the top of the heavy-load balloon; the anchoring balloon is an overpressure balloon made of a polyethylene material, is in a transversely-arranged streamline shape, and has the cable membrane structure characteristic that the longitudinal reinforcing ribs and the circumferential reinforcing ribs are tied on the ball membrane to form a bulge. The invention further comprises a control method of the combined high-altitude balloon, mooring posture control and track guidance are achieved through the anchoring balloon, and the anchoring balloon enables the size and buoyancy of the heavy-load balloon to be kept constant through the air storage and pressurization functions. The problem that an existing high-altitude balloon freely flies along with wind and cannot conduct active track guiding is solved.

Description

Technical Field

[0001] The present application relates to the field of high-altitude balloon design in an aerostat system, and in particular to the design of a combined moored balloon with a trajectory guidance function. Background Art

[0002] High-altitude balloons are currently the only platforms that can stably fly in near-space and can carry all kinds of payloads for space science experiments. High-altitude balloons are made of linear low-density polyethylene (LLDPE) film material. According to the pressure difference between the inside and outside of the balloon, high-altitude balloons can be divided into zero-pressure balloons and super-pressure balloons. Zero-pressure high-altitude balloons were developed earlier. There is an exhaust pipe at the bottom of the zero-pressure balloon that is connected to the atmosphere. The interior is only affected by the helium pressure gradient and cannot withstand a large internal and external pressure difference. It adopts the natural shape proposed by Upson in 1939. Zero-pressure balloons have the advantages of high flying altitude and heavy load. However, due to the influence of the temperature difference between day and night, the volume of the zero-pressure balloon shrinks when the temperature drops, which reduces the buoyancy and the flying altitude. It is necessary to maintain the level flight altitude by throwing sand and other methods, which shortens the flight time. At present, the maximum volume of conventional heavy-loaded zero-pressure balloons can reach 1 million m 3 Above, the load reaches 3.6T, and the flight altitude is close to 40km. Under the influence of the temperature difference between day and night, the volume and shape of the zero-pressure balloon change, resulting in a height difference. In engineering, solid ballast or helium exhaust is often used to maintain the flight altitude, but it has an irreversible impact on the total mass and buoyancy of the balloon, and it is impossible to achieve reversible height control, which is not suitable for long-duration flight.

[0003] The super-pressure balloon is closed to the outside world and has a certain internal and external pressure difference to resist changes in environmental temperature. The volume of the super-pressure balloon can remain unchanged, and it can maintain a constant flight altitude to achieve the goal of long-term airborne flight. At present, super-pressure balloons mostly adopt a "pumpkin-shaped" design, which uses a geometric configuration with an increased local curvature radius and reinforcing ribs to jointly withstand the internal and external pressure difference. As super-pressure balloons develop in the direction of large-scale and heavy-loaded, the membrane stress caused by overpressure will inevitably increase gradually, and due to the complex structure, it faces many technical problems. NASA established the ULDB project in 1998, with the goal of developing a balloon aircraft that can transport a payload of 2721kg to 33.5km for up to 100 days. ULDB chose the pumpkin super-pressure balloon design. After years of development, the current volume has reached 530,000 m 3 , but it has never been able to achieve the heavy-load and long-flight goals proposed by ULDB.

[0004] Considering that balloons need to respond to changing atmospheric environments during long-duration flights, such as changes in atmospheric isobaric surfaces and zero-wind layer heights, or need to have certain navigation control functions, such as avoiding entering no-fly zones by mistake, and controlling flight trajectories with the help of atmospheric wind directions at different altitudes, reversible control of flight altitude will be beneficial to the improvement of long-duration balloon flights and flight performance, thereby ensuring the smooth completion of high-altitude scientific experiments. The practice of balloon altitude and trajectory control can be traced back to the flight of the Montgolfier hot air balloon by the Marquis de Rozier of France in 1785. Rozier adjusted the flight altitude of the balloon by changing the air temperature. Later, with the development of balloon technology, balloonists proposed many altitude control methods, such as throwing ballast, discharging or filling lifting gas, or using atmospheric environment, wind speed, etc., but the control effect was not good or reversible control could not be achieved. Inspired by the airship altitude control method, balloonists introduced a new control method using a double-ball system, using the air auxiliary airbag as ballast, and developed the AB type (Air Ballast) balloon altitude control method. Air is injected into the airbag to increase the weight of the balloon system, causing the balloon altitude to drop, and vice versa. The typical layout of the AB type balloon is shown in Figure 1, which is designed by Lachenmeier, Saito, Businger and Steren. Since the beginning of the 1990s, the AB type balloon has developed rapidly, with increasingly complex internal structures and increasing reliability. For example, Google balloons have also chosen the AB type control method. Professor Paul Voss of the University of Massachusetts proposed another altitude control double-ball system, called the DE type (Differential Expansion) balloon, in which the main zero-pressure balloon bears the main load, and a small super-pressure balloon is designed at the bottom or inside, and a helium circulation circuit is set up to communicate with the main balloon (the typical layout is shown in Figure 1, the balloon configuration designed by Voss). The super-pressure balloon inhales helium from the main balloon to reduce the volume of the main balloon and reduce the altitude of the balloon. If the super-pressure balloon discharges helium into the main balloon, increasing the volume of the main balloon, the floating altitude will increase.

[0005] These combined balloons are only designed to achieve long-duration flight and altitude adjustment. By changing the flight altitude, the balloon is placed in a flight environment with different wind speeds and directions, passively changing the flight direction, and cannot actively control the balloon's flight trajectory. This patent combines balloon styles to not only have long flight time and heavy-load functions, but also actively adjust the attitude angle of the anchored balloon to achieve trajectory guidance. Summary of the invention

[0006] This application proposes a combined high-altitude balloon and control method to achieve heavy-load, long-flight, controllable trajectory flight, solving the problem that the current high-altitude balloons fly freely with the wind and cannot be actively guided. And further improve the long-flight and heavy-load performance of the balloon. From the perspective of the combined balloon, the three functions of heavy load, long flight time and trajectory control are achieved at the same time, providing a reference for the high-altitude balloon to achieve the ULDB flight goal as soon as possible.

[0007] On the one hand, an embodiment of the present application proposes a combined high-altitude balloon, including an anchored balloon and a heavy-loaded balloon, wherein the anchored balloon is towed on the top of the heavy-loaded balloon; the anchored balloon is a super-pressure balloon made of polyethylene material, has a horizontally placed streamlined shape, and has a cable-membrane structure characterized in that the longitudinal reinforcement ribs and the circumferential reinforcement ribs form a bulge on the balloon membrane.

[0008] Preferably, the heavy-load balloon is a zero-pressure balloon with a circumferential stress of zero.

[0009] Preferably, a propeller is installed at the head and / or tail of the moored balloon.

[0010] Preferably, flanges are installed at the head and tail of the anchored balloon, which are connected to the heavy-load balloon through an ascending air pipe and a descending air pipe respectively.

[0011] Preferably, the moored balloon and the heavy-loaded balloon are connected by a rope cage, and the rope cage is suspended at the bottom of the moored balloon through multiple points.

[0012] Preferably, the mooring balloon is externally covered with a rib-free polyethylene film.

[0013] Preferably, the middle section of the mooring balloon is welded with a thin film.

[0014] The embodiments of the present application also provide a control method for a combined high-altitude balloon, using the combined high-altitude balloon described in any one of the embodiments of the present application, tethered attitude control and trajectory guidance are achieved through an anchored balloon, and the anchored balloon maintains a constant volume and buoyancy of the heavy-loaded balloon through an air storage and pressurization function.

[0015] In one embodiment, the control method further includes, by connecting a descending air pipe and an ascending air pipe between the moored balloon and the heavy-loaded balloon, the moored balloon replenishes helium to the heavy-loaded balloon at night, and the heavy-loaded balloon inputs helium to the moored balloon during the day.

[0016] In one embodiment, the control method further comprises changing the flight direction of the combined system by changing the angle of attack and / or sideslip angle of the moored balloon by means of a propeller installed on the moored balloon.

[0017] At least one of the above technical solutions adopted in the embodiments of the present application can achieve the following beneficial effects:

[0018] The combined balloon design proposed in the present invention combines the advantages of large zero-pressure balloons and streamlined super-pressure balloons, and jointly realizes the three functions of heavy load, long flight time and trajectory guidance. It can not only give play to the advantages of zero-pressure balloons in being suitable for heavy loads and high flight altitudes, but also reduce the restrictions of ground distribution stations on the balloon's flight trajectory and duration, and make up for the shortcomings of zero-pressure balloons in duration and trajectory control. Continuously improving the flight performance of high-altitude scientific balloons can provide a good flight platform for conducting more complex balloon-borne scientific experiments. The present invention provides a useful reference for the development of near-space aerostat technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0020] Figure 1.a ~e are various types of combined balloon configurations in the prior art, among which

[0021] Figure 1.a Designed for Lachenmeier.T.(1991)

[0022] Figure 1.b Designed for Saito (2010)

[0023] Figure 1.c Designed for Businger (1996)

[0024] Figure 1.d Designed for Al an Stern (2017)

[0025] Figure 1.e Designed for Paul B Voss (2005)

[0026] Figure 2 This is an embodiment of the combined high-altitude balloon structure of the present application;

[0027] Figure 3 The working state structure diagram of the polyethylene film mooring balloon for this application;

[0028] Figure 4 Design diagram for zero-pressure balloon;

[0029] Figure 5 Design drawings for the moored balloon's appearance;

[0030] Figure 6 The force curves of the moored balloon membrane in the longitudinal and circumferential directions;

[0031] Figure 7 To bear the longitudinal and circumferential reinforcements of the moored balloon membrane;

[0032] Figure 8 Cutting pattern for the membrane of the anchoring balloon. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0034] The present invention aims to adopt a combined moored balloon design for existing large-scale heavy-load zero-pressure balloons to achieve three major functions of heavy load, long flight time and trajectory guidance.

[0035] The patent proposes to combine the zero-pressure balloon and the PE airship to give full play to the advantages of their respective structures and jointly achieve the three functions of heavy load, long flight time and trajectory control. The invention provides a set of design schemes for the combined balloon and introduces them with specific calculation examples. The specific contents include the design of the heavy-load natural-shaped balloon, the cable membrane structure design of the upper anchored balloon, the combination implementation method and flight operation.

[0036] The technical solutions provided by various embodiments of the present application are described in detail below in conjunction with the accompanying drawings.

[0037] Figure 2 This is an embodiment of the combined high-altitude balloon structure of the present application. Combined airships are generally considered to be one of the solutions for achieving long-duration flights. A combined high-altitude balloon proposed in an embodiment of the present application includes an anchor balloon 21 and a heavy-load balloon 22, and the anchor balloon is towed on the top of the heavy-load balloon. The heavy-load balloon is a zero-pressure balloon with a circumferential stress of 0. The anchor balloon is a super-pressure balloon made of polyethylene material, which is a horizontal streamline shape, and has a cable membrane structure characterized by longitudinal reinforcement ribs and circumferential reinforcement ribs that form a bulge 23 on the balloon membrane.

[0038] The heavy-load balloon is also called the main balloon, which can carry a payload by tying a pod 25 through a rope cage 24. The pod can also include flight control, measurement and control devices, solar panels, energy storage batteries, propellers, etc. A parachute 26 can also be configured under the heavy-load balloon and connected to the pod. In one embodiment, a zero-pressure balloon is used as the main balloon to provide heavy-load buoyancy, and the structure and shape still use a natural shape with zero circumferential stress.

[0039] In one embodiment of the present application, the main balloon design parameters are: volume 1120000m 3, film thickness 20.32μm, flight altitude 38.4km, load weight 2.75T, maximum diameter 140m, sphere height 121m, mass 1.8T, moment of inertia: 2870000kgm 2 .

[0040] In some embodiments, the balloon made of polyethylene material is referred to as a PE airship. The PE airship used adopts longitudinal and circumferential reinforcement ribs to withstand stress. The PE airship is used as an air storage airbag to transport helium to compensate for the buoyancy of the main zero-pressure balloon when the volume shrinks at night, thereby achieving highly stable and long-duration flight. Different from the previous arrangement of placing the PE airship below the main zero-pressure balloon, the patent tethers the PE airship above the main balloon so that the combined airship system has a certain trajectory guidance function.

[0041] The mooring balloon selected for this application is a polyethylene cable membrane super-pressure balloon with a streamlined shape. Since the shape of the balloon is similar to that of corn, it is called a "corn kernel" super-pressure balloon. The corn kernel super-pressure balloon has the advantages of constant flight altitude and long flight time, but its structure is complex, and its flight altitude and load are limited. If the corn kernel super-pressure balloon is used as an mooring balloon towed on top of a large heavy-load balloon, the tethered attitude control and trajectory guidance functions can be realized. At the same time, the gas storage and pressurization function of the mooring balloon makes the volume and buoyancy of the main balloon below constant, realizing long-duration flight.

[0042] In one embodiment of the present application, a corn kernel superpressure balloon is used as an anchoring balloon, and its design parameters are: volume 10000m, membrane thickness 38μm, maximum pressure 1000Pa, maximum sphere diameter 8.8m, sphere length 67.5m, and mass 201.7kg.

[0043] The head and / or tail of the moored balloon are equipped with propellers 27 to achieve balloon twisting. Preferably, the airship is placed horizontally and the airship shape is trimmed into a streamlined shape to reduce resistance, and propellers are installed at the head and tail to achieve balloon yaw operation.

[0044] The combined high-altitude balloon of the present application can deliver a 3.6T payload to an altitude of 40km and fly around a set location for a long time.

[0045] Figure 3 The working state structure diagram of the polyethylene film mooring balloon of the present application is shown in FIG. Preferably, flanges 31 are installed at the head and tail of the mooring balloon, which are connected to the heavy-load balloon through the ascending air pipe 28 and the descending air pipe 29 respectively.

[0046] Preferably, the moored balloon and the heavy-loaded balloon are connected by a rope cage 32, and the rope cage is suspended from the bottom of the moored balloon by a multi-point suspension rope 33. The moored balloon and the heavy-loaded balloon below are connected by a rope cage to utilize the yaw stability brought by the large rotational inertia of the heavy-loaded balloon.

[0047] Preferably, the mooring balloon is covered with a non-ribbed polyethylene film 34 on the outside.

[0048] Preferably, the middle section of the moored balloon is welded with a film 35 to ensure symmetry between the left and right bubbles, see partial schematic diagram A.

[0049] The anchored balloon is provided with reinforcement rib binding nodes 38 distributed at various locations, which are the intersections of the longitudinal reinforcement ribs 36 and the circumferential reinforcement ribs 37. The small bulge 23 of the balloon membrane formed by the reinforcement ribs increases the local curvature radius of the balloon membrane to reduce the stress, as shown in the partial schematic diagram B.

[0050] The embodiments of the present application also provide a control method for a combined high-altitude balloon, using the combined high-altitude balloon described in any one of the embodiments of the present application, tethered attitude control and trajectory guidance are achieved through an anchored balloon, and the anchored balloon maintains a constant volume and buoyancy of the heavy-loaded balloon through an air storage and pressurization function.

[0051] Affected by the temperature difference, when the pressure difference of the main balloon increases, the excess helium is discharged into the super-pressure balloon through the ascending air pipe. When the temperature decreases, the super-pressure balloon inflates the main balloon through the descending air pipe to ensure that the volume does not change. Therefore, in one embodiment, the control method further includes, in order to resist the reduction in volume and buoyancy of the main balloon caused by the temperature difference between day and night, by connecting the descending air pipe and the ascending air pipe between the anchoring balloon and the heavy-load balloon, the anchoring balloon replenishes helium to the heavy-load balloon at night, and the heavy-load balloon inputs helium to the anchoring balloon during the day to achieve the gas storage function.

[0052] In one embodiment, the control method further includes changing the attack angle and / or sideslip angle of the moored balloon by a propeller installed on the moored balloon to change the flight direction of the combined system. If the attack angle and sideslip angle of the corn grain airship are changed, the combined airship system is subjected to pitch and yaw torques, thereby changing the flight direction of the combined airship.

[0053] The combined balloon of the present application is a non-traditional combined balloon, and its design and manufacturing are characterized by certain complexity and diversity. Technical research is carried out on several key technologies. The present application provides a design and / or manufacturing method for a combined balloon system.

[0054] The balloon system and the manufacturing method thereof proposed in this application include an anchored balloon and a heavy-loaded balloon, and the manufacturing methods thereof. 3 Heavy-load balloon, 10,000 m 3 This is explained using an anchored balloon as an example.

[0055] First, about the main balloon design. Figure 4 This is the design drawing of the zero-pressure balloon. The main balloon adopts a natural shape with zero circumferential stress. 3The main balloon membrane is a 23μm polyethylene film with 214 membranes, a maximum membrane width of 1.99m, a bottom angle of 50.15°, and a busbar length of 207.11m. The balloon surface area is 53020.90m 2 The double-layer head is 70.32m long, the balloon membrane mass is 1149.98kg, the double-layer throw mass is 323.02kg, the mass of the reinforcement belt used is 265.93kg, and the total mass of the balloon is close to 1.8T.

[0056] The second is the corn-kernel super-pressure balloon tethered to the head of the zero-pressure balloon. Figure 5 This is the design drawing of the moored balloon shape. Specifically, it is an axisymmetric structure, with the axis horizontal, the left and right ends as poles, and the meridian lines intersecting at the poles. The circumferential line is a closed curve where the surface perpendicular to the axis intersects with the main balloon surface. The axial profile contour line ignores the bulge and is smoothed as the mother line. The GNVR shape is adopted, which consists of four segments: ellipse segment, cylinder segment, arc segment and parabola segment. The equation is:

[0057]

[0058]

[0059]

[0060] Where D max =15.83m, the length of the ellipse segment is 1.25D max , the length of the cylindrical segment is 1.32D max , the length of the arc segment is 1.625D max The overall length is 3.05D max In the generatrix equation, x is the axial coordinate of the balloon, y is the radius of the cross-section, and D max is the diameter of the largest cross-sectional circumference of the moored balloon.

[0061] The corn kernel superpressure balloon used as the mooring balloon has 32 bulges along the longitudinal direction, that is, 31 circumferential reinforcing ribs. There are 30 longitudinal reinforcing ribs. The longitudinal lengths of each bulge are [6.62, 2.7, 2.45, 2.21, 2.21, 1.96, 2.21, 1.96, 1.96, 1.72, 1.72, 1.96, 1.72, 1.72, 1.96, 1.96, 1.96, 1.96, 1.96, 1.96, 2.21, 1.96, 1.96, 2.21, 2.21, 2.7, 2.7, 5.15] m. The fully inflated mooring balloon is as follows Figure 3 shown.

[0062] Figure 6The force curves of the moored balloon membrane in the longitudinal and circumferential directions are shown. The bulges at both ends of the balloon can be appropriately extended in the longitudinal direction due to the small force. At the same time, the membrane stress reaches the maximum value at the maximum diameter in the middle, which is close to 7MPa.

[0063] Figure 7 The anchored balloon membrane is subjected to the force of the warp and circumferential reinforcement ribs. The maximum circumferential tension is close to 400kg. If the reinforcement ribs are still made of 3mm diameter PBO fiber ropes, the tension of a single rope can reach 800kg, which can still meet the needs of the circumferential reinforcement ribs. The plane cutting shape of each bulge after unfolding is fitted to obtain the plane cutting pattern of the anchored balloon as shown below Figure 8 As shown. The surface area of ​​a single membrane reaches 214.58m 2 , with a mass of 7.69kg.

[0064] The outer contour in the figure is the plane cut film shape of the anchored balloon finally obtained; the edge shape 82 of the balloon film required by the simulation calculation is similar to the wave shape and is not suitable for processing and manufacturing. Therefore, the first busbar 81 is fitted on the basis of the wave shape to facilitate processing. The second busbar 83 is the meridian reinforcement busbar after the surface of the tethered balloon is bulged under the action of the circumferential reinforcement line 85; the shape of the third busbar 84 is the shape of the balloon busbar if the bulge configuration is not adopted, but a smooth simple rotating body structure. It can be concluded that after the balloon is bulged due to the reinforcement ribs, the balloon needs more balloon film material, that is, the first busbar 81 has a lot more balloon film material than the third busbar 84.

[0065] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of further restrictions, the elements defined by the sentence "comprises..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0066] It will be understood by those skilled in the art that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0067] Those skilled in the art will understand that unless otherwise defined, all terms (including technical, technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs.

[0068] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A combined high-altitude balloon, characterized in that: It comprises an anchor balloon and a heavy-load balloon. The anchor balloon is towed on the top of the heavy-load balloon. The anchor balloon is a super-pressure balloon made of polyethylene material, has a horizontal streamline shape, and has a cable membrane structure characterized in that the longitudinal reinforcement ribs and the circumferential reinforcement ribs form a bulge on the balloon membrane.

2. A combined high-altitude balloon as claimed in claim 1, characterized in that: The heavy-load balloon is a zero-pressure balloon with a circumferential stress of zero.

3. A combined high-altitude balloon as claimed in claim 1, characterized in that: A propeller is installed at the head and / or tail of the anchored balloon.

4. The combined high-altitude balloon according to claim 1, characterized in that: The head and tail of the anchored balloon are provided with flanges, which are connected with the heavy-load balloon through an ascending air pipe and a descending air pipe respectively.

5. The combined high-altitude balloon according to claim 1, characterized in that: The mooring balloon and the heavy-load balloon are connected by a rope cage, and the rope cage is suspended at the bottom of the mooring balloon through multiple points.

6. The combined high-altitude balloon according to claim 1, characterized in that: The mooring balloon is covered with a non-ribbed polyethylene film on the outside.

7. The combined high-altitude balloon according to claim 1, characterized in that: The middle section of the anchored balloon is welded with a thin film.

8. The method for controlling a combined high-altitude balloon according to any one of claims 1 to 7, characterized in that: The moored balloon is used to realize tethered attitude control and trajectory guidance. The moored balloon maintains constant volume and buoyancy of the heavy-loaded balloon through the gas storage and pressurization function.

9. The control method according to claim 8, characterized in that: By connecting the descending air tube and the ascending air tube between the anchored balloon and the heavy-load balloon, the anchored balloon replenishes helium to the heavy-load balloon at night, and the heavy-load balloon supplies helium to the anchored balloon during the day.

10. The control method according to claim 8, characterized in that: The flight direction of the combined system is changed by changing the angle of attack and / or sideslip angle of the anchored balloon through the propeller installed on the anchored balloon.

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