Strategy for ensuring the safety of an airship in the event of overheating of its solar generator

Abstract

The present invention relates to a strategy for ensuring the safety of an airship in the case of heat generation of a solar generator of the airship. A stratospheric airship, the stratospheric airship includes a non-rigid balloon-shaped hull, the non-rigid balloon-shaped hull is equipped with a solar generator disposed on the upper part of the non-rigid balloon-shaped hull, the solar generator is intended to be irradiated by the sun during flight, the airship includes: at least one device for managing the center-of-gravity position of the airship; at least one device for stabilizing the attitude of the airship; and a module for coupling control of the devices, the module is configured to control the airship in a manner that causes the airship to rotate approximately half a turn about its longitudinal axis when the traveling speed of the airship relative to the surrounding air is lower than a first threshold and / or the temperature of the solar generator is higher than a second threshold, so as to protect the solar generator from being irradiated by the sun.

Description

Technical Field

[0001] The present invention relates to a non-rigid airship platform, commonly known by its English name "blimp", equipped with a solar generator. Background Art

[0002] The vast majority of tropospheric airships do not use solar generators, but rather non-renewable energy sources such as kerosene. The troposphere is located between the Earth's surface and the stratosphere, and the stratosphere is the second layer of the Earth's atmosphere, including between the troposphere (below) and the mesosphere (above). Depending on latitude and season, the altitude of the upper limit of the troposphere (tropopause) is approximately 8 km to 15 km.

[0003] On the other hand, solar generators are commonly used on stratospheric airships. It is known to perform thermal control of the solar generator based on the installation of a heat exchanger and a thermal protection member built into the solar generator, for example, as described in "Thermal protection method of the solar array for stratospheric airships" by Junhui Meng, Zhongbing Yao, Huafei Du, Mingyun Lv in Applied Thermal Engineering 111 (2017) 802–810. In terms of altitude, speed, and availability, even if the ideal performance of such an airship cannot be obtained, the impact of such a solution on mass is significant, thus endangering the feasibility of the solution.

[0004] In addition, overheating of the solar generator may be caused by the airship traveling too slowly relative to the surrounding air and thus experiencing insufficient forced convection. Summary of the Invention

[0005] The object of the present invention is to alleviate the above problems and, in particular, to avoid overheating of the solar generator in the case of too low forced convection.

[0006] One aspect of the present invention proposes a stratospheric airship comprising a non-rigid balloon-shaped hull equipped with a solar generator disposed on the upper part of the non-rigid balloon-shaped hull, the solar generator being intended to be irradiated by the sun during flight, the airship comprising:

[0007] at least one device for managing the position of the center of gravity of the airship;

[0008] at least one device for stabilizing the attitude of the airship; and

[0009] A module for coupling control of the device, the module being configured to control the airship in a manner such that the airship rotates approximately half a turn about its longitudinal axis when the traveling speed of the airship relative to the surrounding air is lower than a first threshold and / or the temperature of the solar generator is higher than a second threshold, so as to protect the solar generator from solar irradiation.

[0010] Therefore, when the speed of the airship relative to the surrounding air is lower than the first threshold (when it is higher than the first threshold, thermal regulation by convection with the surrounding air prevents the solar generator and thus prevents overheating of the balloon-shaped hull and its gas), in this case, the present invention makes it possible to avoid damage to the stratospheric airship. If the sun shines on the solar generator all the time, the temperature of the solar generator will rise rapidly. Similarly, when the temperature of the solar generator exceeds the second threshold, or when both conditions are met, the present invention makes it possible to avoid damage to the stratospheric airship. In this type of case, the present invention makes it possible to avoid rupture of the solar generator and damage to the balloon-shaped hull supporting the solar generator by raising the temperature of the balloon-shaped hull material below the solar generator, or by heating the lift-generating gas and increasing the internal pressure so as to increase the tension of the balloon-shaped hull material to prevent damage to the solar generator.

[0011] Therefore, such a stratospheric airship has the ability to hide the solar generator from the sun, thereby preventing the solar generator from rising in temperature under the action of the solar flux, thus reducing the associated thermal stress and mechanical stress. It also makes it possible to avoid increasing the thermal flux generated towards the non-rigid balloon-shaped hull and liable to cause damage or even rupture of the non-rigid balloon-shaped hull, and limits the heating of the lift-generating gas inside the non-rigid balloon-shaped hull due to conduction through the balloon-shaped hull, thereby limiting the increase in internal pressure, which increase in internal pressure may also cause the balloon-shaped hull to rupture.

[0012] Coupling control means the coordinated management of the device for stabilizing the attitude of the airship and the device for managing the center of gravity position of the airship. This coupling also includes detecting that the airspeed has dropped below a first predefined threshold and / or the temperature of the solar generator has risen above a second predefined threshold.

[0013] In one embodiment, the first threshold is lower than 10 m / s -1 .

[0014] Specifically, a high enough speed makes it possible to maximize forced convection and thus reduce the thermal impact of the solar flux on the solar generator and on the balloon-shaped hull. As a result, the engineering specifications of these components are relaxed or loosened.

[0015] According to one embodiment, the first threshold is equal to 5 m / s-1 。

[0016] Such a threshold requires raising the specifications related to the temperature tolerance of the solar generator and the balloon-shaped hull, but provides more margin with respect to the maximum airspeed that the airship can reach, and this eases the constraints imposed on the maneuvers that can be performed during flight.

[0017] In one embodiment, the second threshold is below 120 °C and, for example, equal to 100 °C.

[0018] In one embodiment, the device for managing the position of the center of gravity of the airship is an active device.

[0019] Using an active device for managing the position of the center of gravity makes it possible to optimize the configuration of the airship to meet requirements, facilitate the maneuvers required during the various flight phases, and make the airship more robust in the face of changes in the surrounding environment.

[0020] According to one embodiment, the active device for managing the position of the center of gravity of the airship includes a controlled member configured to displace a heavy object.

[0021] For example, the controlled member may include an actuator and a return device.

[0022] The heavy object may be a component carried on the airship specifically for performing this function, or may be a component that the airship uses for other functions during flight and that becomes movable in order to add this active management feature.

[0023] The active device for managing the position of the center of gravity of the airship may include at least one member capable of moving around the balloon-shaped hull.

[0024] In one embodiment, the device for managing the position of the center of gravity of the airship is a passive device.

[0025] For example, the passive device for managing the position of the center of gravity of the airship may include a component carried on the airship that is pre-positioned so that the center of gravity of the airship is located between the longitudinal axis of the airship and the solar generator.

[0026] The main advantage of this passive management of the center of gravity position is that it is operationally simpler and does not involve any mechanisms compared to an active system.

[0027] The on-board components may include at least one battery and / or at least one fuel cell and / or at least one fuel tank.

[0028] According to one embodiment, the device for stabilizing the attitude of the airship is an active device.

[0029] For example, an active device for stabilizing the attitude of an airship may include aerodynamic control surfaces and / or gimbal-mounted thrusters and / or side thrusters and / or flywheels.

[0030] In one embodiment, the device for stabilizing the attitude of the airship is a passive device.

[0031] For example, a passive device for stabilizing the attitude of an airship may be a pendulum return caused by a predetermined setting of the center of gravity of the airship away from the longitudinal axis.

[0032] The aim is to set the center of gravity of the airship in such a way that, as required, the center of gravity of the airship is on the correct side of the longitudinal axis, i.e., when the airspeed is below a first threshold and / or when the temperature of the solar generator is above a second threshold, the center of gravity of the airship is located between the longitudinal axis of the airship and the upward-facing sun-exposed solar generator, and under standard conditions, the center of gravity of the airship is located between the longitudinal axis of the airship and the payload pod.

[0033] Another aspect of the present invention also proposes a method for controlling a stratospheric airship, the stratospheric airship including a non-rigid balloon-shaped hull equipped with a solar generator arranged on an upper part of the non-rigid balloon-shaped hull, the solar generator being intended to be irradiated by the sun during flight, wherein the position of the center of gravity of the airship and the stabilization of the attitude of the airship are controlled in a coupled manner such that when the traveling speed of the airship relative to the surrounding air is below a first threshold and / or the temperature of the solar generator is above a second threshold, the airship rotates approximately half a turn about its longitudinal axis to protect the solar generator from sun exposure. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be better understood from the following description of several embodiments given by way of completely non-limiting examples illustrated by the drawings, in which:

[0035] Figure 1 A stratospheric airship according to one aspect of the present invention is schematically illustrated;

[0036] Figure 2a A stratospheric airship according to one aspect of the present invention is schematically illustrated; and

[0037] Figure 2b A stratospheric airship according to Figure 2a an aspect of the invention is schematically illustrated;

[0038] Figure 3a A stratospheric airship according to one aspect of the present invention is schematically illustrated; and

[0039] Figure 3b A stratospheric airship according to Figure 3aStratospheric airship of aspects of the invention.

[0040] In all the figures, parts having the same reference numerals are similar. Detailed description

[0041] Figure 1 The stratospheric airship 1 is depicted, which includes a non-rigid balloon-shaped hull 2, a gondola 3, a thruster 4, and a device 5 for stabilizing the attitude of the airship.

[0042] The non-rigid balloon-shaped hull 2 includes a solar generator 6 disposed on the upper part of the non-rigid balloon-shaped hull 2, which is intended to be irradiated by the sun during flight. The solar generator 6 can be inside or outside the balloon-shaped hull 2.

[0043] The gondola 3 houses a power supply and a control system, as well as the technical equipment required for various tasks of the airship, which may involve observation, surveillance, or telecommunications.

[0044] The solar generator 6 enables the power supply of on-board equipment during the day and recharges the electrical energy storage system, which then takes over the power supply of on-board equipment at night.

[0045] The airship 1 includes at least one device 7 for managing the center of gravity position of the airship; at least one device 5 for stabilizing the attitude of the airship; and a module 8 for coupling control of the devices, such that when the traveling speed of the airship relative to the surrounding air is lower than a first threshold S1 and / or the temperature of the solar generator is higher than a second threshold S2, the airship 1 rotates approximately half a turn around its longitudinal axis AL to protect the solar generator 6 from solar irradiation.

[0046] Even if not all cases are detailed in the following part of the present specification, each of the device 7 for managing the center of gravity position of the airship and the device 5 for stabilizing the attitude of the airship can be active or passive.

[0047] The airship 1 includes a sensor 9 that measures the traveling speed of the airship 1 relative to the surrounding air.

[0048] The first threshold S1 is lower than 10 m / s -1 and advantageously equal to 5 m / s -1 .

[0049] The second threshold S2 is lower than 120 °C and advantageously equal to 100 °C.

[0050] When the device 7 for managing the position of the center of gravity of the airship 1 is an active device, the device 7 may include a controlled member configured to displace the heavy weight 7a. The controlled member may include an actuator 7b and a return device 7c, and the heavy weight 7a may include a member carried on the airship 1 that is specifically designed to perform this function (such as ballast) or a member that also performs other functions (such as an energy storage device).

[0051] When the device 7 for managing the position of the center of gravity of the airship 1 is a passive device, or in other words, when the management of the position of the center of gravity of the airship 1 is completely passive, the device 7 may include a member carried on the airship 1 that is pre-positioned in such a way that the center of gravity CdG of the airship 1 lies between its longitudinal axis AL and the solar generator 6 located above and facing the sun during standard operation. The on-board member may include at least one battery, and / or at least one fuel cell and / or at least one fuel tank or any other device with a total mass sufficient to perform this function.

[0052] Standard operation means the operation of the airship 1 when the speed of the airship 1 relative to the surrounding air is higher than or equal to a first threshold S1 and / or when the temperature of the solar generator is lower than or equal to a second threshold S2.

[0053] When the device 5 for stabilizing the attitude of the airship 1 is an active device, the device 5 may include aerodynamic control surfaces and / or gimbal-mounted thrusters and / or side thrusters and / or flywheels.

[0054] When the device 5 for stabilizing the attitude of the airship 1 is a passive device, the device 5 may include a swing return caused by setting the center of gravity CdG of the airship 1 in such a way that the center of gravity CdG of the airship 1 lies between the longitudinal axis AL of the airship 1 and the solar generator 6 located above and facing the sun during standard operation.

[0055] Now, two detailed non-limiting embodiments follow.

[0056] Figure 2a and Figure 2b An example of a stratospheric airship 1 is illustrated, which includes a passive device 7 for managing the position of the center of gravity CdG of the airship 1, and the passive device 7 is connected to an active device 5 for stabilizing the attitude of the airship 1.

[0057] The position of the center of gravity CdG of the airship 1 is positioned at a desired location, that is, on the same side as the solar generator 6 with respect to the longitudinal axis AL, or in other words, between the longitudinal axis AL and the top of the balloon-shaped hull where the solar generator 6 is provided. During the standard operation of the airship 1, the solar generator 6 faces the sun, and the attitude is controlled by the active device 5 for stabilizing the attitude, as Figure 2a shown.

[0058] This operation is carried out on the ground before takeoff by changing the position of various on-board equipment (avionics, energy storage devices, etc.).

[0059] Once in flight, available actuators 5 such as the following are used to affect the attitude of the airship: aerodynamic control surfaces and / or gimbal-mounted thrusters and / or side thrusters and / or flywheels, which form active devices for stabilizing the attitude of the airship.

[0060] If the speed of the airship 1 drops below a first threshold S1 relative to the surrounding air and / or the temperature of the solar generator 6 reaches a second threshold S2, the airship 1 rotates approximately 180° about its longitudinal axis AL, and the airship positions itself Figure 2b in the position shown, in which the solar generator 6 is protected from the sun's rays.

[0061] Figure 3a and Figure 3b illustrates a stratospheric airship 1 that includes an active device 7 for managing the position of the center of gravity CdG of the airship 1, which is coupled to a passive device 5 for stabilizing the attitude of the airship 1.

[0062] The position of the center of gravity CdG is modified during flight by shifting heavy objects in the desired direction. To do this, certain modules 7a mounted on the balloon-shaped hull 2 are movable. Battery modules are particularly advantageous for this operation due to their significant mass. These modules 7a can be made movable by a very reliable device based on return devices 7c and actuators 7b acting in opposite directions or by an actuator system on rails or cables.

[0063] In the standard case, the center of gravity CdG of the airship 1 is positioned at the desired location, i.e., on the side opposite the solar generator 6 with respect to the longitudinal axis AL, or in other words, between the longitudinal axis AL and the payload pod 3. In the standard operation of the airship 1, the solar generator 6 faces the sun, and the attitude is passively stabilized by the swinging return action caused by the position of the center of gravity CdG and the attitude is controlled by the active device 5 for stabilizing the attitude, as Figure 3a shown.

[0064] If the speed of the airship 1 drops below a first threshold S1 relative to the surrounding air and / or the temperature of the solar generator 6 reaches a second threshold S2, the active device 7 for managing the position of the center of gravity CdG brings the center of gravity CdG back between the longitudinal axis AL and the top of the balloon-shaped hull 2 provided with the solar generator 6. The effect of this action is to generate a swinging moment, causing the airship to rotate 180° about its longitudinal axis AL, and the airship positions itself Figure 3bThe position shown, at which the solar generator 6 is protected from solar irradiation.

Claims

1. A stratospheric airship (1), the stratospheric airship comprising a non-rigid balloon-shaped hull (2), the non-rigid balloon-shaped hull being equipped with a solar generator (6) disposed on an upper portion of the non-rigid balloon-shaped hull (2), the solar generator being intended to be irradiated by the sun during flight, the stratospheric airship (1) comprising: at least one management device (7) for managing the center-of-gravity position of the stratospheric airship; at least one stabilizing device (5) for stabilizing the attitude of the stratospheric airship; and a module (8) that controls the attitude of the stratospheric airship to cause the stratospheric airship to rotate approximately half a turn about its longitudinal axis (AL) when the traveling speed of the stratospheric airship (1) relative to the surrounding air is lower than a first threshold (S1) and / or when the temperature of the solar generator is higher than a second threshold (S2), so as to protect the solar generator (6) from being irradiated by the sun, wherein the at least one management device (7) for managing the center-of-gravity position of the stratospheric airship comprises components carried on the stratospheric airship, the components being pre-positioned such that the center of gravity of the stratospheric airship is located between the longitudinal axis (AL) of the stratospheric airship and the solar generator (6), and wherein the at least one stabilizing device (5) for stabilizing the attitude of the stratospheric airship comprises aerodynamic control surfaces.

2. The stratospheric airship (1) according to claim 1, wherein, The first threshold value (S1) is less than 10 ms -1 .

3. The stratospheric airship (1) according to claim 2, wherein, The first threshold value (S1) is equal to 5 ms -1 .

4. The stratospheric airship (1) according to any one of claims 1 to 3, wherein, the second threshold (S2) is lower than 120 °C.

5. The stratospheric airship (1) according to claim 4, wherein, the second threshold (S2) is equal to 100 °C.

6. The stratospheric airship (1) according to claim 1, wherein, the at least one management device (7) for managing the center-of-gravity position of the stratospheric airship is an active device.

7. The stratospheric airship (1) according to claim 6, wherein, the active device for managing the center-of-gravity position of the stratospheric airship comprises a controlled component configured to displace a heavy object (7a).

8. The stratospheric airship (1) according to claim 7, wherein, the controlled component comprises an actuator (7b) and a return device (7c).

9. The stratospheric airship (1) according to claim 7 or 8, wherein, the heavy object comprises a component carried on the stratospheric airship.

10. The stratospheric airship (1) according to claim 6, wherein, the active device for managing the center-of-gravity position of the stratospheric airship comprises at least one component capable of moving around the non-rigid balloon-shaped hull.

11. The stratospheric airship (1) according to claim 1, wherein, the components on the airship include at least one battery and / or at least one fuel cell and / or at least one fuel tank.

12. The stratospheric airship (1) according to claim 1, wherein, the at least one stabilizing device (5) for stabilizing the attitude of the stratospheric airship is a passive device.

13. The stratospheric airship (1) according to claim 12, wherein, the passive device for stabilizing the attitude of the stratospheric airship is a swing return caused by a predetermined setting in which the center of gravity of the stratospheric airship is displaced from the longitudinal axis (AL).

14. A method for controlling a stratospheric airship (1), the stratospheric airship comprising a non-rigid balloon-shaped hull (2), the non-rigid balloon-shaped hull being equipped with a solar generator (6) arranged on the upper part of the non-rigid balloon-shaped hull, the solar generator being intended to be irradiated by the sun during flight, wherein, the position of the center of gravity of the stratospheric airship and the stability of the attitude of the stratospheric airship are controlled in a linked manner by a module in the stratospheric airship, and when the travel speed of the stratospheric airship relative to the surrounding air is lower than a first threshold (S1) and / or when the temperature of the solar generator is higher than a second threshold (S2), the module controls the attitude of the stratospheric airship so that the stratospheric airship rotates by approximately half a turn about its longitudinal axis (AL) to protect the solar generator (6) from being irradiated by the sun, wherein at least one management device (7) for managing the position of the center of gravity of the stratospheric airship comprises components carried on the stratospheric airship, the components being pre-positioned such that the center of gravity of the stratospheric airship is located between the longitudinal axis (AL) of the stratospheric airship and the solar generator (6), and wherein at least one stabilizing device (5) for stabilizing the attitude of the stratospheric airship comprises aerodynamic control surfaces.

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