A separate piston device for deploying folding-wing drones

Abstract

The present invention discloses a detachable piston device for deploying a folding-wing drone, belonging to the technical field of drone equipment. The detachable piston device comprises a piston and a parachute; the upper end surface of the piston is configured to contact the drone; the lower end surface of the piston is connected to the parachute; and the parachute automatically deploys when the piston ascends. The device also defines the dimensions of the piston and the drone. The present invention enables both timely separation from the drone and repeated drone launches. It addresses the current technical problem of drone launchers where the piston fails to disengage in a timely manner, posing a risk of jamming the drone's propeller and thus affecting takeoff.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned equipment, and in particular to a detachable piston device for launching a folding-wing unmanned aerial vehicle. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] A notable feature of folding-wing UAVs is their low cost. They can be deployed from a variety of platforms and patrol in the air. When equipped with different payloads, they can perform tasks such as surveillance and reconnaissance (ISR), target indication, information relay, area blockade, air alert, precision strikes, and damage assessment. The takeoff of folding-wing UAVs requires a UAV launcher, which launches the folding-wing UAV and enables it to take off.

[0004] The current drone launcher includes a launch tube, a piston and a gas generating device; the gas generating device and the piston are located inside the launch tube. The gas generating device uses solid propellant to ignite to generate high-temperature gas, which pushes the piston to move, and then the piston pushes the drone out of the launch tube to complete the launch.

[0005] There are two types of pistons in current drone launchers. One is that when launching a drone, the piston and the drone fly out of the tube together and separate from the drone in the air. If the separation is not timely, there is a risk of the drone propeller being stuck, thus affecting the drone's takeoff; the other is that when launching a drone, a connecting mechanism is used to forcibly retain the piston in the launch tube. Although this solves the problem of piston separation, the mechanism is complex, and the preparation and reloading time is long. In addition, when the piston stops in the tube, it will generate a huge impact force, causing damage to the launch tube, which is not conducive to cluster launch and secondary launch; the piston is also weak and is prone to being shattered. Summary of the Invention

[0006] In order to solve the above problems, the present invention proposes a detachable piston device for launching a folding-wing UAV, which can not only achieve timely separation from the UAV, but also achieve multiple repeated launches of the UAV.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention proposes a detachable piston device for deploying a folding-wing UAV, comprising: a piston and a parachute; the upper end surface of the piston is used to contact the UAV; the lower end surface of the piston is connected to the parachute; when the piston moves upward, the parachute can be automatically deployed.

[0009] Furthermore, a sinking space is provided on the lower end surface of the piston, and the parachute can be folded and placed in the sinking space.

[0010] Furthermore, the parachute rope is connected to the eye nut; the eye nut is connected to the piston via a screw.

[0011] Furthermore, a groove is provided on the upper end surface of the piston.

[0012] Furthermore, the piston is made of engineering plastic.

[0013] Furthermore, the outer peripheral surface of the piston is adapted to the inner wall of the launch tube, and each edge of the piston is chamfered.

[0014] Furthermore, when the piston is located in the launch tube, the parachute is in a folded state; when the piston is separated from the launch tube and is in the process of rising, the parachute is unfolded.

[0015] Furthermore, the volume of the piston is a set volume, and the mass of the piston is a set mass; the set volume and set mass are calculated based on a piston parameter calculation model; wherein the piston parameter calculation model includes geometric dimension constraints to ensure that the piston does not rotate in the launch tube and mechanical constraints to ensure that the acceleration of the UAV meets the requirements during the launch process.

[0016] Furthermore, the projected area of the parachute is a set area; the set area is calculated based on a force balance equation after the parachute is deployed.

[0017] Furthermore, the piston is a rectangular body.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention proposes a detachable piston device for launching a folding-wing drone, comprising a piston and a parachute. The upper end surface of the piston is used to contact the drone, and the lower end surface of the piston is connected to the parachute; and when the piston moves upward, the parachute can automatically deploy. When the drone is launched using this piston device, the piston can be launched out of the launch tube, and when the piston is separated from the launch tube, the parachute opens, increasing the wind resistance of the piston and reducing the piston's flight speed in the air, so that the piston is separated from the tail of the drone in time, thereby not causing interference with the drone's rotor. The piston can also land quickly to provide a clear environment, effectively reducing interference with subsequently launched drones. The parachute can also reduce the piston's landing speed, reduce the impact force between the piston and the ground, and increase the piston's service life, so that the piston can be reloaded into the launch tube for subsequent drone launches.

[0020] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings in the specification, which constitute a part of this application, are used to provide further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute improper limitations on this application.

[0022] Figure 1 This is a schematic diagram of the structure of the piston device and the folding-wing UAV in the launch tube disclosed in the embodiment;

[0023] Figure 2 A schematic diagram of a folding-wing UAV and a piston device disclosed in an embodiment being ejected from a cylinder;

[0024] Figure 3 This is a schematic diagram of the separation of the piston and the drone after the parachute is opened according to the embodiment;

[0025] Figure 4 This is a schematic diagram of the deployment of a piston device parachute disclosed in an embodiment;

[0026] Figure 5 Schematic diagram of the gap between the piston and the inner wall of the launch tube disclosed in the embodiment;

[0027] Figure 6 A schematic diagram of a piston and an inner wall of a launch tube being stuck in the embodiment disclosed;

[0028] Figure 7 This is a force distribution diagram of the piston disclosed in the embodiment.

[0029] Among them: 1. Folding-wing drone, 2. Piston, 3. Parachute, 4. Launch tube, 5. Gas generator, 6. Eye nut, 7. Sinking space. DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] In the present invention, terms such as "fixed connection," "connected," and "connection" should be interpreted broadly to mean a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediary. Relevant researchers or technicians in this field may determine the specific meanings of these terms in the present invention based on specific circumstances, and they should not be construed as limitations of the present invention.

[0034] Example 1

[0035] In this embodiment, a detachable piston device for deploying folding-wing UAVs is disclosed, which can enable the piston to be immediately separated from the UAV when it is fired out of the launch tube. During loading, it is easy to operate, strong and durable, and can be launched repeatedly to meet the needs of cluster launch and secondary launch.

[0036] Specifically, this embodiment discloses a separate piston device for deploying a folding-wing UAV, such as Figure 1-Figure 7 As shown, it includes: a piston 2 and a parachute 3; the upper end surface of the piston 2 is used to contact the drone; the lower end surface of the piston 2 is connected to the parachute 3; when the piston 2 moves upward, the parachute 3 can be automatically deployed.

[0037] The piston 2 of this embodiment is installed in the launch tube 4 to launch the folding-wing UAV 1. During the pneumatic ejection of the folding-wing UAV 1, the piston 2 provides the thrust for the UAV to exit the launch tube, and prevents the high-temperature gas generated by the gas generator 5 during the gunpowder explosion from directly contacting the aircraft, thereby protecting the aircraft from damage.

[0038] By installing a parachute 3 on the lower end surface of the piston 2, during the launch process of the folding-wing UAV 1, when the piston 2 is ejected from the launch tube 4, the parachute 3 opens, increasing the wind resistance of the piston 2, reducing the flight speed of the piston 2 in the air, and actively separating the piston 2 from the tail of the UAV; the parachute can also reduce the landing speed of the piston and reduce the impact with the ground; the service life of the piston is increased, the flight distance of the piston in the air is reduced, the piston can land quickly to provide a clear environment, effectively reducing interference with subsequently launched UAVs, and the piston can be quickly reloaded, thereby improving launch efficiency.

[0039] like Figure 4 As shown, in this embodiment, a sinking space 7 is provided on the lower end surface of the piston 2 , and the parachute 3 can be folded and placed in the sinking space 7 .

[0040] Preferably, the parachute cord is connected to the eye nut 6; the eye nut 6 is connected to the piston 2 via a screw.

[0041] The parachute canopy is folded according to the triangular folding method, and the parachute ropes are folded by the figure-8 winding method. After the ropes and canopy are folded, the parachute 3 can be placed in the sinking space 7 of the piston 2.

[0042] When the piston 2 is located in the launch tube 4, the parachute 3 is in a folded state; when the piston 2 is separated from the launch tube 4 and rises, the parachute 3 is unfolded.

[0043] A card slot is provided on the upper end surface of the piston 2; the card slot is used to clamp the tail of the drone; the card slot can be adjusted according to the shape of the tail of the drone to be launched to meet the launch requirements of different types of drones.

[0044] The piston 2 of this embodiment is made of engineering plastics. The engineering plastics material has high elasticity, impact resistance, and a low friction coefficient, which can effectively increase the service life of the piston.

[0045] Preferably, the piston 2 is made of engineering plastic by 3D printing.

[0046] In traditional aircraft launchers, when the piston is pushed by high-pressure gas and moves axially in the launch tube, it usually deviates from the center of the launch tube and is squeezed against the wall of the launch tube, generating a large force, causing the piston to get stuck and wedged, reducing the launch speed of the drone and causing the launch to fail.

[0047] The outer peripheral surface of the piston 2 of this embodiment is adapted to the inner wall of the launch tube 4, and the edges of the piston 2 are rounded to ensure that the piston will not get stuck when moving in the launch tube.

[0048] This embodiment discloses a detachable piston device for deploying a folding-wing drone. Before loading the parachute into a launch tube 4, the parachute cords 3 are first connected to an eye nut 6 via a knot. The canopy is then folded using the triangular folding method, with the cords folded using a figure-of-eight winding method. After the canopy cords are folded, the eye nut 6 is bolted to the lower end face of the piston. Finally, the canopy cords are placed in a recessed space 7 in the lower end face of the piston.

[0049] During loading, the piston 2 is placed into the launch tube 4 from the front, and the launch tube body is kept at a certain angle. Under the action of gravity, the piston 2 naturally slides into the bottom of the tube and contacts the gas production chamber, thereby sealing the top of the gas production chamber.

[0050] During launch, the gas generator 5 is activated to generate high-temperature gas, which in turn pushes the folding-wing drone 1 out of the launch tube. Once the piston 2 is fully exposed, the parachute 3 rapidly inflates and opens under the action of air, decelerating the piston and achieving active separation.

[0051] The detachable piston device disclosed in this embodiment deploys a parachute after the piston exits the cylinder, actively decelerating it and rapidly separating it from the tail of the drone. The parachute simultaneously reduces the piston's touchdown speed and flight distance, increasing its service life while also reducing its flight distance. This allows for rapid clearance during cluster launches, effectively minimizing interference with subsequent drone launches.

[0052] To ensure that the piston 2 does not get stuck when moving in the launch tube, the volume of the piston in this embodiment is limited to a set volume, and the mass of the piston is limited to a set mass; the set volume and set mass are calculated based on a piston parameter calculation model; wherein the piston parameter calculation model includes geometric dimensional constraints to ensure that the piston does not rotate in the launch tube and mechanical constraints to ensure that the acceleration of the drone during the launch process meets the requirements.

[0053] Specifically, the set volume and set mass are calculated based on the fillet radius of the piston edge, the rotation angle of the piston when the piston and the launch tube are stuck, the vertical angle of the launch tube, the launch gas pressure, the gap between the piston and the inner wall of the launch tube, the piston height, and the piston parameter calculation model.

[0054] Preferably, the piston is a rectangular body, and preferably, the rectangular body is a cuboid. Taking a cuboid piston as an example, the piston parameter calculation model is described in detail.

[0055] For a rectangular piston, the height direction of the piston is consistent with the axial direction of the launch tube. When the side diagonal of the piston is greater than the side length of the inner wall of the launch tube, the piston can be guaranteed not to rotate in the launch tube due to dimensional constraints. The side of the piston refers to the plane outside the upper and lower end surfaces of the piston. Therefore, the geometric dimensional constraint that ensures that the piston does not rotate in the launch tube can be expressed as:

[0056] h 2 +( L - x ) 2 > L 2 ;

[0057] Where, L is the side length of the inner wall of the launch tube, x is the gap between the piston and the inner wall of the launch tube, h is the piston height, which refers to the distance between the upper end surface and the lower end surface of the piston.

[0058] In order to avoid stress concentration during application, the piston edge is rounded. The radius of the piston edge rounding is RAssuming that the piston and the launch tube are stuck, when the piston and the launch tube are stuck, the rounded corners of the piston edge are tangent to the inner wall of the launch tube. At this time, the piston rotates from each side parallel to the corresponding surface of the inner wall of the launch tube until the piston and the launch tube are stuck. The rotation angle of the piston is α, and the vertical angle of the launch tube when launching the drone is β, which satisfies the geometric relationship conditions:

[0059] L =( L - x -2R)cosα+( h -2R)sinα+2R;

[0060] L =A1B=A1R1+R1D+CD+BC;

[0061] R1D=(L- x -2R)cosα;

[0062] CD=( h -2R)sinα;

[0063] Where A1B is the distance between point A1 and point B, A1R1 is the distance between point A1 and point R1, R1D is the distance between point R1 and point D, CD is the distance between point C and point D, and BC is the distance between point B and point C. Figure 5 、 Figure 6 As shown, Figure 5 Schematic diagram of the gap between the piston and the inner wall of the launch tube. Figure 6 Schematic diagram of the piston getting stuck with the inner wall of the launch tube after deflection in the launch tube. In the figure, points A1 and A2 are the two tangent points between the piston and the inner wall of the launch tube; points R1, R2, R3 and R4 are the centers of the chamfered corners of the two opposite edges of the lower end face of the piston and the centers of the chamfered corners of the two opposite edges of the upper end face of the piston. The four edges are four parallel edges, including the edge where the piston is tangent to the inner wall of the launch tube, and the edge to which point R1 belongs is the same as the edge to which point A1 belongs, the edge to which point R3 belongs is the same as the edge to which point A2 belongs, and points R1, R2, R3, R4 and A Point 1 and point A2 are on the same plane, and the plane is parallel to the other two inner walls of the launch tube, which are not tangent to the piston; Point B is the intersection of the extended line of the line connecting points A1 and R1 and the inner wall of the launch tube, Point C is the projection of point R3 on the line connecting points A1 and B, that is, the line connecting points R3 and C is perpendicular to the line connecting points A1 and B; Point E is the intersection of the extended line of the line connecting points A2 and R3 and the line connecting points R4 and R1, Point D is the intersection of the line connecting points E and R2 and the line connecting points A1 and B, A1R1 is equal to the fillet radius R, and BC is equal to the fillet radius R.

[0064] When the gas generator is fired, high-temperature gas is generated to push the piston. When a critical stuck state is generated, the friction between the piston and the launch tube increases. From the geometric relationship, it can be seen that when a critical stuck state is generated, the positive pressure of point A1 is N 1' increases to the positive pressure at point A1 when there is no sticking N 1 times sinα, that is:

[0065] N 1=m 活塞 gcosβ;

[0066] N 1'=(1+sinα) N 1=(1+sinα)m 活塞 gcosβ;

[0067] like Figure 7 As shown, due to the stagnation between the piston and the inner wall of the launch tube, a new friction force is generated at point A2, and at the same time, a new supporting force is added to the inner wall of the launch tube, which is equal to the positive pressure at point A2. N 2. The friction force at point A2 is μ N 2, N 2 equals N 1', then:

[0068] N 2=(1+sinα) N 1=(1+sinα)m 活塞 gcosβ;

[0069] In this state, to ensure that the acceleration of the drone meets the requirements, we have to:

[0070] High temperature gas pressure (P·S) - system friction loss (μ N ) ≥ (UAV mass + piston mass) × acceleration, where, N is the positive pressure at point A1 when the critical stuck state occurs N 1' and the positive pressure at point A2 N The sum of 2, that is, the mechanical constraint condition to ensure that the acceleration of the UAV during the launch process meets the requirements can be expressed as:

[0071] PS-μ( N 1'+ N 2)≥(m 无人机 +m 活塞 )a;

[0072] Where P is the high-temperature gas pressure generated by the gas launcher, that is, the launch gas pressure, and S is the pressure area. When the jam occurs, it can be approximated as the cross-sectional area of the launch tube, that is, S= L 2 , a is the acceleration of the UAV.

[0073] Therefore, in this embodiment, when determining the set volume and set mass of the piston, the preliminarily determined drone mass m can be used. 无人机 , the fillet radius R of the piston edge, the rotation angle α of the piston when the piston and the launch tube are stuck, the vertical angle β of the launch tube, the launch gas pressure P, and the length of the inner wall of the launch tube L The above formula can be used to calculate the gap between the piston and the inner wall of the launch tube. x , piston height h and piston mass m 活塞 , according to the gap between the piston and the inner wall of the launch tube x and the inner wall length of the launch tube L , calculate the side length of the piston, where the side length of the piston is equal to the side length of the inner wall of the launch tube L Subtract the gap between the piston and the inner wall of the launch tube x ; According to the piston side length and piston height h The piston volume V is calculated; the piston volume and the piston mass are the set volume and the set mass of the piston.

[0074] In order to prevent the piston from being damaged by colliding with the ground after descending to the ground, this embodiment limits the projected area of the parachute to a set area; the set area is calculated based on the force balance equation after the parachute is deployed.

[0075] Specifically, in order to prevent the piston from being damaged by colliding with the ground after descending to the ground, this embodiment limits the descending speed of the parachute after deployment, and limits the descending speed of the parachute after deployment to be less than or equal to a set speed, which can be 5m / s.

[0076] The projected area D of a parachute can be calculated using the parachute tension equation. When the weight of the load is equal to the parachute tension, the parachute descends at a constant speed. The force balance equation for the deployed parachute can then be expressed as:

[0077] ;

[0078] Where F is the parachute's pulling force, or the required resistance, which can be approximated by the weight of the load, m·g, where m is the piston mass and g is the acceleration due to gravity; C d is the air resistance coefficient, which is determined by the shape and material of the parachute; ρ is the air density ；D is the projected area of the parachute; v is the speed of the parachute relative to the air, that is, the descent speed; the air resistance coefficient C d This can be determined through wind tunnel testing or numerical simulation. The drag coefficient varies for different parachute shapes. For example, a spherical parachute has a drag coefficient of approximately 0.5, while a square parachute has a drag coefficient of 1.

[0079] Once the drag coefficient, descent speed, and parachute tension F are determined, the projected area of the parachute can be calculated using the following formula:

[0080] ;

[0081] The projected area D calculated by the above formula is the set area.

[0082] The separate piston device proposed in this embodiment can effectively prevent the piston from getting stuck by limiting the mass and volume of the piston and the projected area of the parachute, and effectively ensure a low and uniform landing after the parachute is deployed, thereby reducing the impact force when the piston touches the ground, preventing damage to the piston, and increasing the service life of the piston.

[0083] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A separate piston device for launching a folding-wing UAV, characterized in that: include: A piston and a parachute; the upper end surface of the piston is used to contact the drone; the lower end surface of the piston is connected to the parachute; When the piston moves upward, the parachute can be automatically deployed; The outer circumference of the piston is adapted to the inner wall of the launch tube, and the edges of the piston are rounded. The volume of the piston is a set volume, and the mass of the piston is a set mass. The set volume and set mass are calculated according to a piston parameter calculation model. The piston parameter calculation model includes geometric constraints to ensure that the piston does not rotate in the launch tube and mechanical constraints to ensure that the UAV acceleration meets the requirements during launch. The geometric constraints are expressed as: ； Where L is the length of the inner wall of the launch tube, x is the gap between the piston and the inner wall of the launch tube, and h is the piston height, which refers to the distance between the upper end surface and the lower end surface of the piston. The rotation angle of the piston is α, and the vertical angle of the launch tube when launching the drone is β. The geometric relationship conditions are as follows: ; ; ; ; Wherein, R is the radius of the chamfered corners of the piston edge, A1B is the distance between points A1 and B, A1R1 is the distance between points A1 and R1, R1D is the distance between points R1 and D, CD is the distance between points C and D, BC is the distance between points B and C, A1 and A2 are the two tangent points of the piston and the inner wall of the launch tube, B is the intersection of the extended line of the line connecting points A1 and R1 and the inner wall of the launch tube, points R1, R2, R3 and R4 are the centers of the chamfered corners of the two opposite edges of the lower end face of the piston and the centers of the chamfered corners of the two opposite edges of the upper end face of the piston, C is the projection of point R3 on the line connecting points A1 and B, D is the intersection of the line connecting points E and R2 with the line connecting points A1 and B, and point E is the intersection of the extended line connecting points A2 and R3 with the line connecting points R4 and R1; The mechanical constraint condition is expressed as: ; Where P is the high-temperature gas pressure generated by the gas launcher, that is, the launch gas pressure, and S is the pressure area. When the jam occurs, it can be approximated as the cross-sectional area of the launch tube, that is, S=L 2 , N1' is the positive pressure at the critical stuck state point A1, N2 is the positive pressure at the critical stuck state point A2, For drone quality, is the mass of the piston, and a is the acceleration of the drone.

2. A separate piston device for launching a folding-wing UAV according to claim 1, characterized in that: A sinking space is provided on the lower end surface of the piston, and the parachute can be folded and placed in the sinking space.

3. The detachable piston device for launching a folding-wing UAV according to claim 1, characterized in that: The parachute cord is connected to the eye nut; the eye nut is connected to the piston via a screw.

4. The detachable piston device for launching a folding-wing UAV according to claim 1, characterized in that: A clamping groove is arranged on the upper end surface of the piston.

5. The detachable piston device for launching a folding-wing UAV according to claim 1, characterized in that: The piston is made of engineering plastic.

6. The detachable piston device for launching a folding-wing UAV according to claim 1, characterized in that: When the piston is in the launch tube, the parachute is in a folded state; when the piston is separated from the launch tube and rising, the parachute is unfolded.

7. The detachable piston device for launching a folding-wing UAV according to claim 1, characterized in that: The projected area of the parachute is the set area; the set area is calculated based on the force balance equation after the parachute is deployed.

8. The detachable piston device for launching a folding-wing UAV according to claim 1, characterized in that: The piston is a rectangular body.

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