A flexible vent device adapted for use with an active control cushion airbag

Abstract

A flexible vent device suitable for active control type buffer airbag, which can be opened according to predetermined overload or pressure. According to the requirements of airbag volume, buffer time and maximum pressure in the bag, the required vent area is determined, the corresponding area of the vent is opened on the buffer airbag, a layer of bursting membrane is covered on the vent for structural sealing, a flexible fabric cylinder is arranged outside the vent bursting membrane to bear the force of the bag body during the buffer process, the flexible fabric cylinder is closed by a closing rope before opening, the closing rope is limited by passing through the buckle on the flexible fabric cylinder during installation, and a cutter needs to be passed through at the same time. The closing rope and the cutter are fixed on the outer side of the flexible fabric cylinder, so the outer side of the fabric cylinder needs to be provided with a plurality of closing rope fixing buckles and a cutter fixing sleeve.

Description

TECHNICAL FIELD

[0001] The present application relates to a flexible vent device suitable for an active control type buffer airbag for a spacecraft active vent type buffer airbag vent. BACKGROUND

[0002] The spacecraft ground landing buffer method mainly includes compressible material buffer, braking rocket or anti-thrust engine buffer, mechanical transmission type buffer (landing leg type) and airbag buffer. The airbag buffer is widely used in the fields of aerospace and air-drop soft landing due to its small weight and packing volume, good folding performance, low cost and certain anti-rollover capability. The new generation manned spacecraft and reusable satellite of China currently adopt the airbag buffer as the landing buffer device for the lossless recovery of the landing cabin.

[0003] The airbag buffer can be divided into vent type airbag buffer and closed type airbag buffer according to the energy absorption mode. The vent type airbag buffer mainly discharges the energy absorbed in the landing process of the cabin through the gas movement in the bag to achieve the purpose of landing buffer. The active vent type airbag buffer mainly determines the overload of the cabin or the pressure in the bag during the buffer process. When the predetermined value is reached, the controller on the cabin sends the vent command to the airbag buffer, so that the single airbag actively vents or the multiple sub-airbags actively vent in a predetermined sequence. Therefore, the active vent type airbag buffer can control the overload value and pressure value when venting according to the needs, and can also make different sub-airbags open step by step according to a certain sequence, which not only can control the overload peak value of the buffer process, but also can improve the landing stability.

[0004] The active vent of the airbag buffer is realized by the actuating device on the vent and the control device on the cabin. At the same time, in order to control the maximum overload of the buffer process and the residual speed after the buffer, the size of the vent also needs to be reasonably designed.

[0005] The existing vent type airbag buffer currently adopts the passive sensing opening type vent device which is self-adaptive to the pressure in the bag. That is, the airbag vent is covered with a certain strength of burst membrane. When the pressure in the bag reaches the burst strength of the burst membrane, the burst membrane is passively burst to vent outward. This type of vent device cannot set different sub-airbags to open in a certain sequence when the number of airbags is greater than 2, and the adaptability to complex ground is poor, the time consistency of opening is poor, and even some vents cannot be opened, which may cause the side turning and overturning of the object being buffered during the landing process. SUMMARY

[0006] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and solve the problems of landing overload control and landing stability control.

[0007] The application is achieved by the following technical solutions

[0008] A flexible exhaust device for active control type buffer air bag, comprising a burst membrane, a flexible fabric cylinder, a closing rope and a cutter.

[0009] The burst membrane is sealed and covered on the exhaust port of the buffer air bag, and the flexible fabric cylinder is located outside the burst membrane to bear the force received by the air bag during the buffering process. The flexible fabric cylinder is closed by the closing rope before being opened, and the cutter is used to cut the closing rope.

[0010] The cutter is connected with an external controller.

[0011] Preferably, the closing rope and the cutter are fixed on the outer side of the flexible fabric cylinder, and the outer side of the flexible fabric cylinder is provided with a plurality of buckles for fixing the closing rope and a fixing sleeve for the cutter.

[0012] Preferably, a plurality of flexible exhaust devices are arranged on the buffer air bag according to the exhaust requirement of the buffer air bag.

[0013] Preferably, the area of the exhaust port of the buffer air bag is calculated by the following formula:

[0014]

[0015] Wherein

[0016]

[0017] In the formula, W is the average mass flow of the gas in the air bag during the buffering time, V is the volume of the air bag, ρ is the density of the gas in the air bag, t is the buffering time, μ is the flow attenuation coefficient, γ is the specific heat ratio of the gas, P is the maximum absolute pressure of the air bag during the exhaust, V is the specific volume of the gas under the exhaust pressure, and g is the acceleration of gravity. 排 比容

[0018] Preferably, the plurality of flexible exhaust devices are opened step by step for exhaust.

[0019] Preferably, during the buffering process, the pressure in the air bag or the overload of the landing cabin is collected to the controller, and when the predetermined value is reached, the controller sends an exhaust command to the cutter to cut the closing rope, the flexible fabric cylinder is opened, the burst membrane is burst, and the buffer air bag is exhausted.

[0020] Preferably, the material strength of the flexible fabric cylinder is equivalent to the material strength of the buffer air bag body.

[0021] Compared with the prior art, the application has the following beneficial effects:

[0022] ​​(1) The buffer airbag is mainly used for landing buffer of a spacecraft, controls the buffer overload in a predetermined range, and makes the landing attitude as stable as possible to avoid the situation of tilting or rolling. The core key technology of the exhaust port buffer airbag is the reasonable design of the exhaust port area, which is an effective means to control the overload peak value. The reasonable exhaust mode and exhaust strategy can make the airbag exhaust according to the predetermined program, which can ensure the stability of the landing process. This active control type exhaust mode is particularly important for manned spacecraft with high safety requirements and spacecraft with reuse requirements.

[0023] (2) The exhaust port device adopts a flexible design instead of a rigid design, which can effectively reduce the weight of the exhaust port and save the packaging volume, and has a positive significance for spacecraft with strict requirements on weight and volume.

[0024] (3) The exhaust port area is set according to the airbag volume, buffer time and maximum pressure in the airbag, which can effectively control the overload value in the buffer process.

[0025] (4) According to the pressure and overload value of different sub-airbags, different sub-airbags are set to exhaust according to a certain program to ensure the landing stability. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Schematic diagram of the closed exhaust port form of the flexible fabric cylinder before sealing.

[0027] Figure 2 Schematic diagram of the closed exhaust port form of the flexible fabric cylinder after sealing. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0029] The application is aimed at a flexible active control type exhaust port device for the buffer airbag of spacecraft landing cabin without loss of recovery. The exhaust port area is calculated according to the airbag volume, buffer time and maximum pressure in the airbag, and the corresponding area of the exhaust port is opened on the buffer airbag (when the exhaust port needs to be set as multiple, the sum of the areas of the multiple exhaust ports needs to be consistent with the total required area), and a layer of blasting membrane (which can be TPU film or other film that can be heat sealed or glued together with the airbag body) is covered on the exhaust port for structural sealing, and a flexible fabric cylinder is arranged outside the exhaust port blasting membrane to bear the force on the airbag body during the buffer process. The flexible fabric cylinder is sewn together with the airbag body by sewing, and the sewing strength needs to be able to bear the maximum pressure in the airbag. The flexible fabric cylinder is closed by a closing rope before opening, and the closing rope is limited by passing through the buckle on the flexible fabric cylinder during installation. A cutter is also passed through during installation, which is used to cut the closing rope when the exhaust port is opened. The cable of the cutter is connected to the controller on the spacecraft landing cabin. The closing rope and the cutter are fixed on the outside of the flexible fabric cylinder, so the outside of the fabric cylinder needs to be provided with several closing rope fixing buckles and a cutter fixing sleeve.

[0030] The cutter is the actuating device for opening the exhaust port, and the airbag pressure and cabin overload can be used as the starting signal. When pressure is used as the opening signal, a pressure sensor needs to be arranged on the buffer airbag to measure the pressure in the airbag during the buffer process and provide the signal to the control device. When overload is used as the starting signal, an overload sensor needs to be arranged on the landing cabin to measure the overload of the cabin during the buffer process and provide the signal to the control device. When the pressure or overload reaches the predetermined value, the control device on the landing cabin sends an instruction to the cutter, the cutter cuts the closing rope, the flexible fabric cylinder opens, the exhaust port blasting membrane is then blown up under the action of the gas pressure in the airbag, and the gas in the airbag is discharged outward. This method can realize step-by-step opening of different exhaust ports on the same airbag according to the ground landing terrain and the stability of the landing cabin during the landing process, and can also realize step-by-step discharge of different sub-airbags to keep the stability of the landing posture of the cabin.

[0031] A flexible exhaust port device suitable for active control type buffer airbag. The size of the required exhaust port is calculated first, and the corresponding size of the exhaust port is opened on the airbag. A blasting membrane, a flexible fabric cylinder, a closing rope and a cutter are arranged on the exhaust port. During the buffer process, the pressure in the airbag or the overload signal of the landing cabin is collected and provided to the control device. When the predetermined value is reached, the control device sends an exhaust instruction to the cutter, the closing rope of the exhaust port is cut, the flexible fabric cylinder is opened, the blasting membrane is blown up, and the airbag is exhausted.

[0032] The exhaust port is used to control the exhaust speed of the buffer airbag, thereby controlling the buffer overload peak. The exhaust port area is calculated by formula (1), and the exhaust port diameter and the number of exhaust ports are obtained by the exhaust port area:

[0033]

[0034] wherein:

[0035] W - average mass flow rate of the gas in the airbag during the buffer time, kg / s; has wherein V is the airbag volume, p is the airbag gas density, t is the buffer time;

[0036] μ - flow decay coefficient, generally taken as 0.7;

[0037] g - gravitational acceleration, taken as 9.81 m / s 2 ;

[0038] γ - specific heat ratio of the gas; for diatomic gases (nitrogen, oxygen) γ is taken as for monatomic gases (argon, helium) γ is taken as

[0039] P 排 - maximum absolute pressure of the airbag during the venting, initially taken as the same value as Pmax, MPa;

[0040] V 比容 - specific volume of the gas at the venting pressure, m 3 / kg;

[0041] for nitrogen, it can be taken as

[0042] The flexible venting port is composed of Figure 1 and Figure 2 . Wherein: 1) the material strength of the flexible fabric sleeve should be comparable to that of the airbag body; 2) the distance from the top end of the fixed buckle of the closure rope to the bottom of the flexible fabric sleeve should be slightly smaller than the radius of the venting port; 3) after the cutter is placed in the fixed sleeve, it is fixed on the flexible fabric sleeve by three stitches, and the position of the rope hole of the cutter should be flush with the top end of the fixed buckle of the closure rope. The closure rope is sequentially threaded through the fixed buckle and the rope hole of the cutter and then knotted and fixed, and the knot is preferably located opposite the cutter.

[0043] A flexible venting port device suitable for an actively controlled buffer airbag, the device and method need to first calculate the size of the required venting port and open a venting port of the corresponding size on the buffer airbag, and set a bursting membrane, a flexible fabric sleeve, a closure rope and a cutter on the venting port. During the buffering process, the pressure in the airbag or the overload of the landing cabin body is collected to the control device, and when the predetermined value is reached, the control device gives the venting instruction to the cutter, cuts off the closure rope, opens the flexible fabric sleeve, bursts the bursting membrane, and the airbag vents.

[0044] The device and method can use the pressure in the air bag and the overload of the cabin as the starting mode. When the pressure is used as the opening signal, a pressure sensor is arranged on the air bag to measure the pressure in the air bag during the buffering process and provide a signal to the control device. When the overload is used as the starting signal, an overload sensor is arranged on the landing cabin to measure the overload of the cabin during the landing process and provide a signal to the control device. When the pressure or the overload reaches a predetermined value, the control device on the landing cabin sends an instruction to the cutter, the cutter cuts the closing rope, the flexible fabric cylinder is opened, the exhaust port burst membrane is subsequently burst, the gas in the air bag is discharged outward, and the purpose of active exhaust of the air bag is achieved. According to the landing terrain and the stability of the cabin during the landing process, the method can realize step-by-step opening of different exhaust ports on the same air bag, and can also realize step-by-step exhaust of different sub-air bags, so that the stability of the cabin in the landing posture is maintained.

[0045] The contents not described in detail in the specification of the present application are known to those skilled in the art.

[0046] Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application by using the disclosed methods and technical contents without departing from the spirit and scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, which does not depart from the technical solutions of the present application, belongs to the protection scope of the technical solutions of the present application.

Claims

1. A flexible exhaust port device adapted to an actively controlled airbag, characterized in that, The invention relates to a buffer airbag, comprising a burst membrane, a flexible fabric tube, a closing rope and a cutter. The burst membrane is sealed on the exhaust port of the buffer airbag, the flexible fabric tube is outside the burst membrane and bears the force of the buffer airbag, the flexible fabric tube is closed by the closing rope before opening, and the cutter is used to cut the closing rope. The cutter is connected with an external controller. A plurality of flexible exhaust port devices are arranged on the buffer airbag according to the exhaust requirement of the buffer airbag. The area of the exhaust port of the buffer airbag is calculated by the following formula: where W is the average mass flow rate of the gas in the bladder during the buffer time, V is the volume of the bladder, p is the density of the gas in the bladder, t is the buffer time; μ is the flow decay coefficient; γ is the specific heat ratio of the gas; P 排 is the maximum absolute pressure of the bladder at the time of venting; V 比容 is the specific volume of the gas at the venting pressure; g is the acceleration due to gravity.

2. The flexible vent of claim 1, wherein, Wherein 3. The flexible vent of claim 1, wherein, The closing rope and the cutter are fixed on the outer side of the flexible fabric tube, and a plurality of buckles for fixing the closing rope and a cutter fixing sleeve are arranged on the outer side of the flexible fabric tube.

4. The flexible vent of claim 1, wherein, The plurality of flexible exhaust port devices are opened step by step.

5. The flexible vent of claim 1, wherein, During the buffer process, the pressure in the buffer airbag or the overload of the landing cabin is collected to the controller, when reaching the predetermined value, the controller sends an exhaust command to the cutter, the closing rope is cut, the flexible fabric tube is opened, the burst membrane is burst, and the buffer airbag is exhausted.

6. The flexible vent device of any one of claims 1 to 5, wherein, The material strength of the flexible fabric tube is equivalent to that of the buffer airbag.

7. The flexible vent device of any one of claims 1 to 5, wherein, The flexible fabric tube is sewn together with the buffer airbag by sewing.

8. The flexible vent device of any one of claims 1 to 5, wherein, The burst membrane is made of TPU film or film that can be heat sealed or glued together with the buffer airbag. The closing rope is installed through the buckles on the flexible fabric tube for limiting.

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