FR3060530A1 - DEVICE FOR EJECTING A PROPULSE PARACHUTE BY BREAKING A CONTAINER FILLED WITH GAS UNDER PRESSURE AND EQUIPPING AN AIRCRAFT WITHOUT PILOT - Google Patents

Abstract

The invention relates to a device for ejecting a parachute equipping an unmanned aircraft, comprising a housing having an opening facing upwards, and a control device detecting an event causing the ejection of a parachute contained in the upper part of the house. The ejection device further comprises a container filled with pressurized gas placed under the parachute and provided with an envelope intended to be broken, and a device for breaking said envelope activated by the control device to break said envelope. According to an improvement, the rupture device comprises a heating element which is pressed onto said envelope in order to break it by heating. According to another characteristic, the heating element is an electrical resistance plated against at least a portion of the periphery of the envelope of the container.

Description

(54) The invention relates to a device for ejecting a parachute fitted to an unmanned aircraft, comprising a housing provided with an opening facing upwards, and a control device detecting an event causing the ejection of a parachute contained in the upper part of the accommodation. The ejection device further comprises a container filled with pressurized gas placed under the parachute and provided with an envelope intended to be ruptured, and a device for rupture of said envelope activated by the control device to rupture said envelope. According to an improvement, the rupture device comprises a heating element which is pressed against said envelope in order to break it by heating. According to another characteristic, the heating element is an electrical resistance pressed against at least part of the periphery of the envelope of the container.

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Device for ejecting a parachute propelled by the rupture of a container filled with gas under pressure and fitted to an unmanned aircraft

1. FIELD OF THE INVENTION

The field of the invention is that of unmanned aircraft, remotely controlled and carrying air support means enabling them to make journeys. In the event of a flight failure, the aircraft suddenly crashes. The invention relates more particularly to an automatic or controlled ejection device of a parachute propelled by the rupture of a container filled with a gas under pressure.

2. TECHNOLOGICAL BACKGROUND

It is known to unmanned aircraft equipped with means of lift in the air allowing them to make journeys above the ground. These devices are usually remotely controlled from a ground control box. This box emits signals indicating in particular the direction of movement according to a three-dimensional reference. Depending on their autonomy, these aircraft can determine their own trajectories, and give information on their situations and operating states. These devices can carry a payload and are heavy enough to cause damage and injury to people if the engines stop, resulting in a free fall.

As a result, French regulations make it mandatory to install a parachute on aircraft, such as drones over 2 kg and under 8 kg flying in an S3 scenario.

For aircraft in the 350 kg to 3 ton range there are compressed air systems inside a polymer bladder contained in a metal cylinder. A pyrotechnic or manual device is used to trigger the ejection of the parachute. These systems are heavy and unsuitable for drones weighing less than 25 kg.

Parachute ejection systems in the range of drones from 2 to 15 kg exist and are based either on the relaxation of a spring or on the implementation of a pyrotechnic charge.

The use of a spring requires a compression device for arming the ejector, either in situ or after dismantling the system in order to better apply the compression force. Maintaining the spring in the compressed position is achieved by mechanical locking using a crimped cable surrounding the coils of the spring or surrounding metal bars themselves resting on the outer coils of the spring. Cable breakage is obtained by heating due to the flow of electric current through the cable. The difficulty comes from keeping the spring compressed at the same time as the cable is crimped. This requires dismantling the system after each trip, even after a test just before the flight as recommended by the regulations.

The compression of the spring can be achieved by closing a cover holding the parachute and the compressed spring inside a box. The difficulty consists in placing the correctly folded parachute in the box and arming the spring while maintaining the parachute in the correct position during the closing of the cover. The ejection is carried out by means of a mechanical device which suddenly releases the cover, the latter then pivoting around a hinge. This has the effect of ejecting the parachute slightly at an angle, which reduces its ejection speed and can send it on the rotating propellers. In addition, the kinematics of the mechanical device can be the subject of malfunction due to the games and potential blockages in the moving parts (mechanical servomotors, gears, friction parts, etc.).

Other devices rest on a parachute fixed to a plate and protected by a cover stretched by elastic wires connected to a retaining hook associated with a servomechanism. In this device, the initial speed of exit of the parachute is random because it mainly depends on the speed of the air flow present during the triggering, the parachute being released more or less by gravity. This device does not comply with regulations which specify that the parachute must be ejected and not released by gravity.

Ejection systems using pyrotechnic processes based on gas cartridges in metal or composite cylinders are effective but are difficult or even impossible to transport by air due to the regulations in force. Powder devices are inherently dangerous and impossible to transport over long distances or by air without special provisions that few drone operators can implement.

There is therefore a real need for a solution which does not have the drawbacks described above, and which proposes an ejection device making it possible to rapidly propel a parachute outside the aircraft. This ejection device must be light, easy to install and comprising elements which do not require any particular constraints for transport.

3. STATEMENT OF THE INVENTION

In a particular embodiment of the invention, there is provided a device for ejecting a parachute fitted to an unmanned aircraft, comprising a housing provided with an opening facing upwards, and a control device detecting an event. causing the ejection of a parachute contained in the upper part of the housing. The ejection device further comprises a container filled with pressurized gas placed under the parachute and provided with an envelope intended to be ruptured, and a device for rupture of said envelope activated by the control device to rupture said envelope. In this way, the parachute is quickly ejected over the aircraft, and its installation before the flight is simple and quick.

According to a first embodiment, the envelope of the container deforms under heat and the rupture device comprises a heating element pressed against said envelope. The heating of said element causes an opening in the envelope of the container and the sudden escape of gas propels the parachute out of the housing. In this way, the ejection device propelling the parachute does not present any particular danger for its installation and transport.

According to another embodiment, the heating element is a flexible electrical resistance plated on at least a portion of the outer perimeter of the container or forming several turns around said perimeter, the breaking device comprises a current generator producing a heating of said resistance . In this way, the components are very common and the parachute ejection device is very inexpensive.

According to another embodiment, the flexible electrical resistance is fixed at the upper periphery of the container, immediately below the folded parachute. In this way, the opening of the container is located very close to the parachute and the released gas propels it more efficiently.

According to another embodiment, the flexible electrical resistance is tensioned by a spring, one end of which is secured to the housing. In this way, the electrical resistance does not risk moving during the elongation caused by its heating.

According to another embodiment, when the rupture device is activated, the control device triggers the stopping of engines which keep the aircraft in flight. In this way, the parachute is less likely to be damaged by the blades driven in rotation by the motors.

According to another embodiment, the control device emits a light and / or sound signal after activating the rupture device of said envelope. In this way, people in the vicinity are alerted to the failure of the aircraft and the triggering of the parachute.

According to another embodiment, the container has a neck having a thread, the bottom of the housing has an annular threaded element on which said neck is screwed, the pressurization of the container being effected by injecting gas through said threaded element annular. In this way, the mounting of the container in the aircraft and its pressurization once mounted is facilitated.

According to another embodiment, the annular threaded element in the lower part of the housing has a valve for manually eliminating the pressure contained in the container. In this way, once a flight has gone off without incident, it is very easy to deactivate the ejection device by purging the container.

According to another embodiment, the control device receives a signal from a remote control on the ground and activates the ejection of the parachute on receipt of said signal. In this way, the operator can trigger the ejection of the parachute on the ground if the flight of the aircraft does not proceed correctly.

4. LIST OF FIGURES

Other characteristics and advantages of the invention will appear on reading the following description, given by way of non-limiting example, and the attached drawings, in which:

FIG. 1 presents a diagram of a drone showing the main elements, according to an exemplary embodiment, FIG. 2 presents a diagram of a device for ejecting a parachute according to a preferred embodiment, FIG. 3 presents a equipment which keeps the resistance taut during its heating.

5. DETAILED DESCRIPTION

In all the figures in this document, identical elements are designated by the same reference numeral.

5.7 General principle

The invention relates to a device for ejecting a parachute fitted to an unmanned aircraft, comprising a housing provided with an opening facing upwards, and a control device detecting an event causing the ejection of a parachute contained in the upper part of the accommodation. The ejection device further comprises a container filled with pressurized gas placed under the parachute and provided with an envelope intended to be ruptured, and a device for rupture of said envelope activated by the control device to rupture said envelope. According to an improvement, the rupture device comprises a heating element which is pressed against said envelope in order to break it by heating. According to another characteristic, the heating element is an electrical resistance pressed against at least part of the periphery of the envelope of the container.

5.2 Description of an embodiment

FIG.l presents a view of a system comprising an aircraft 1 and its remote control unit 2. The aircraft relates to any unmanned flying object provided with means of lifting in the air, among such devices one finds in particular drones civil or military, orbiting systems, etc. The parachute ejection device is in its preferred embodiment more particularly suitable for drones weighing less than 25 kilograms. In the example described, the drone 1 comprises a frame 3, on which is fixed an electronic control card 4, a battery 5 and a plurality of arms 6 terminated by motors 7 which rotate the propellers. The control card 4 comprises a central unit associated with a program, a GPS module making it possible to know the precise position of the drone, an inertial unit, a radio communication module. Depending on the model, the drone is equipped with four arms with radial symmetry and as many motors, or six or eight arms. According to a variant, the suspension arms of the motors form an "H", four motors being arranged at the ends of the branches and two at the intersections. The drone can carry a payload fixed preferably under the chassis, this load can for example be a camera. The drone has feet 8 possibly fitted with shock absorbers 9 at their ends to land on the ground. As a variant, the drone can take on a heat engine, it then consumes fossil fuel.

The remote control unit 2 remotely controls the movements of the drone by communicating with it by a two-way radio link. The drone continuously transmits information such as:

- position obtained by GPS, or any other system for transmitting positioning signals emitted by a fixed point,

- speed obtained by analyzing the evolution of the position, altitude, quality of the radio signal received and of the radio link in general,

- general condition of the drone (battery level, temperature, vibration level, ...)

Depending on the commands issued by the unit 2 and the indications provided by the inertial unit, the control card 4 generates command signals to the various motors 7. The remote control unit 2 has commands for directing the drone, and means display to know its status, for example the charge level of its batteries or the quality of the radio link. An absence of signals from the drone can mean a significant failure, possibly requiring activation of the parachute.

The control card 4 receives the commands sent by the box 2, and calculates the control signals to be transmitted to the motors to carry out the requested movements. The program also performs background tasks such as stabilization of the drone using an inertial unit, and test tasks.

According to the invention, the drone has a device for ejecting a parachute making it possible, in the event of an engine (s) stopping during the flight, to slow down the free fall to minimize damage to the ground and avoid damaging the 'apparatus. This device comprises a housing 10 having an opening facing upwards, this housing is preferably cylindrical and made of fiberglass or composite. It must resist a sudden release of gas at the bottom in order to generate an upward air flow. The ejection device includes a control device 11 continuously analyzing the flight conditions in order to detect an event causing the drone to fall. These events are for example: engine stop, operation of the control card 4, violent collision with another flying object, air hole, etc. As these events result in most cases in a rapid decrease in altitude, the control device generally detects an abrupt decrease in altitude. The control device can have its own power supply so as to operate independently of the electronic control card 4, this characteristic is compulsory if the drone has a weight of more than 4 kilograms, as stipulated by the regulations in force. The ejection of the parachute can also be activated on the ground by the operator who visually observes a free fall of the drone or its evolution outside the flight area, the operator preferably having its own remote control to activate the ejection of the parachute. The control device triggers the engines 7 to stop when the parachute is ejected, for example by cutting off their power supplies.

When such an event occurs, the control device 11 triggers the ejection of a parachute 12 placed in the upper part of the housing 10, the ejection being caused by the rupture of a container 13 filled with gas under pressure placed under the parachute. The occurrence of such an event causes the activation of a mechanism intended to rupture the envelope of the container 13 in order to suddenly release the gas. This gas is preferably air under the pressure of ten bars or less, or an inert gas such as nitrogen. The volume of the container 13 depends on the size of the parachute to be ejected which itself depends on the weight of the drone. Tests using a 0.33 liter plastic container, inflated to a pressure of 4 bars and ejecting a 2.5 square meter parachute worked perfectly for a 4 kg drone.

The rupture mechanism can be a mechanical punch mounted in rotation whose star point pierces the container at a point of weakness. The punch is tensioned by a spring and is released by the movement of the counterweight of an electromagnet which is controlled by the control device 11.

According to a preferred alternative embodiment, the rupture mechanism comprises a heating element which is pressed against the outer envelope of the container 13, this container being made of a material which deforms under heat, plastic in general, for example PET (Polyethylene terephthalate). According to a preferred embodiment, this heating element is an electrical resistance 14 pressed against at least part of the outer perimeter of the container. This resistor is made of constantan or an equivalent metal with a resistance of 5 to 10 ohms / meter. The electrical resistance 14 can be a turn by making the complete turn of the container 13, and possibly several turns. The heating element can be placed in a more fragile place in the container, for example a place where the envelope is thinner, the local fragility of the container should not in itself cause it to rupture simply because of its pressurization.

Fig. 2 shows a preferred embodiment of a device for ejecting a parachute. According to this example, the shape of the housing 10 is cylindrical. The housing 10 follows the shape of a container 13 slipped inside, this container is advantageously a commercial plastic bottle 13 - 0.33 liter capacity with the neck oriented downwards. The bottom of this bottle is surrounded by at least one turn of an electrical resistance supplied by two electrical cables connected to the control device 11. The electrical resistance is pressed against the casing 15 of the bottle. Traveled by a current, the resistance heats up making the plastic soft. Under pressure, the envelope of the container 13 breaks, releasing the pressurized gas and propelling the parachute 12 outside the housing 10. According to an alternative embodiment, the electrical resistance 14 'is placed in the region 16 which adjoins the bottleneck. In this way, most of the bottle 13 is propelled upwards in the direction defined by the cylindrical wall of the container 10, and is ejected from said container 10 by pushing the parachute 12.

This embodiment guarantees an expulsion of the parachute from its housing 10 with an initial speed of 10 meters / second and the immediate tensioning of the lines, this measurement is carried out using a plastic bottle of 0.33 liters, inflated at a pressure of 4 bars.

The inflation of the bottle 13 is preferably carried out when the latter is secured to the container. For this, the container 10 is extended in the lower part by a frustoconical shape ending in a cylindrical ring whose inner wall is threaded. The annular threaded element 17 has a thread corresponding to that of the bottle 13, so that this bottle is secured to the container by screwing using the thread present at its neck. The annular threaded element 17 in the lower part of the housing 10 comprises a valve 18 allowing the filling of the bottle with a gas under pressure by means of a nozzle bringing the gas under pressure, and the maintenance of the gas during the withdrawal of the mouthpiece. Manual pressure on the valve makes it possible to empty the gas contained in the bottle 13. This operation is almost identical to filling an inner tube with a vehicle tire.

It can therefore be seen that the constituent elements of this parachute ejection device are very common and of low cost. Inflation can be carried out using a hand pump fitted with a pressure gauge, or an electric pump capable of producing a pressure of around ten bars.

The operating mode is as follows: the drone 1 and its remote control 2 are brought to the launch site. The operator takes a bottle already surrounded by its electrical resistance and screws it onto the thread of the container. Then, the operator connects a nozzle to the valve and inflates the bottle to the desired pressure. The tip is then removed and it is checked that there is no leakage. The operator then connects the electrical cables for supplying the resistor 14 to the control device 11, and then supplies it just before takeoff. If during the flight, the control device detects a loss of control of the drone causing a free fall, it supplies the electrical resistance 14 causing the rupture of the envelope of the bottle 13. The compressed air is then released propelling towards the up the parachute which opens and slows the fall of the drone.

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Advantageously, the control device 11 also triggers the emission of an audible and / or light signal making it possible to warn the immediate environment of the drone falling. This equipment is mandatory if the drone has a weight of more than 4 kilograms, as stipulated by the regulations in force at least in France, in 2016. In this way, people who may be below it can move away. According to another improvement, the control device emits a signal directly to the remote control 2, or through the electronic control card 4 and its radio communication module, to the remote control 2. In this way, the operator in command can be informed of the situation.

Advantageously, the drone has a transport case comprising spare bottles, previously equipped with their electrical resistance to break the envelope. The case also includes a small electric pump with a pressure switch, which stops inflation when the nominal pressure is reached.

In the case where the electrical resistance goes around the container, its heating causes an elongation which will separate it from the envelope. Fa Fig. 3 presents equipment which makes it possible to keep the resistance taut during its heating. According to this improvement, the electrical resistance is tensioned by a spring 20 which will separate it from a small circumference portion of the container 13. This spring can be a simple metal blade, one end of which is fixed to the interior wall of the housing 10 and the other end has a roller provided with a groove for the passage of the resistance. The two ends of the resistor are connected to the power cables 21 connected to the control device. In this way, the resistance is pressed onto a large part of the envelope of the container 13.

The invention is not limited to the embodiments which have just been described. In particular, the parachute ejection device can be used by any unmanned aircraft, regardless of its size and its propulsion mode.

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Claims (10)

1. Device for ejecting a parachute fitted to an unmanned aircraft (1), comprising a housing (10) provided with an opening oriented upwards, a control device (11) detecting an event causing the ejection of '' a parachute (12) contained in the upper part of the housing, characterized in that it further comprises a container (13) filled with gas under pressure placed under the parachute and provided with an envelope intended to be ruptured, and a rupture device (14) of said envelope activated by the control device (11) to rupture said envelope. 2. Ejection device according to claim 1, characterized in that the envelope of the container deforms under heat and in that the rupture device comprises a heating element (14, 14 ') pressed against said envelope, the heating said element causing an opening in the envelope of the container and the sudden escape of the gas propelling the parachute out of the housing. 3. Ejection device according to claim 2, characterized in that the heating element is a flexible electrical resistance plated on at least a portion of the outer perimeter of the container (13) or forming several turns around said perimeter, the rupture device comprising a current generator producing a heating of said resistance. 4. Ejection device according to claim 3, characterized in that the flexible electrical resistance is fixed at the upper periphery of the container, immediately below the folded parachute. 5. Ejection device according to claim 3 or 4, characterized in that the flexible electrical resistance (14) is tensioned by a spring (20), one end of which is secured to the housing (10). 6. Ejection device according to any one of the preceding claims, characterized in that, when the rupture device (14) is activated, the control device (11) triggers the stopping of motors ( 7) which keep the aircraft in flight. 5 7. Ejection device according to any one of the preceding claims, characterized in that the control device (11) emits a light and / or sound signal after activating the rupture device (14) of said envelope. 8. Ejection device according to any one of the preceding claims, characterized in that the container (13) has a neck having a thread and in that the bottom of the housing (10) has an annular threaded element (17) on which said neck is screwed, the pressurization of the container being effected by injecting gas through said annular threaded element. 15 9. Ejection device according to claim 8, characterized in that the annular threaded element (17) in the lower part of the housing (10) has a valve for manually eliminating the pressure contained in the container (13). 10. Ejection device according to any one of the preceding claims, 20 characterized in that the control device (11) receives a signal from a remote control on the ground and activates the ejection of the parachute (12) upon receipt of said signal. 1/2 2/2