Separated piston device for putting folding wing unmanned aerial vehicle

Abstract

The invention discloses a separated piston device for putting of a folding wing unmanned aerial vehicle, and belongs to the technical field of unmanned aerial vehicle equipment. The separated piston device comprises a piston and a parachute; the upper end face of the piston is used for making contact with the unmanned aerial vehicle. The lower end face of the piston is connected with the parachute. When the piston ascends, the parachute can be automatically unfolded, and the sizes of the piston and the unmanned aerial vehicle are limited. The unmanned aerial vehicle can be separated from the unmanned aerial vehicle in time, and the unmanned aerial vehicle can be repeatedly launched for multiple times. The technical problem that a current unmanned aerial vehicle launcher piston is not disengaged in time, the risk that a propeller of an unmanned aerial vehicle is clamped exists, and therefore take-off of the unmanned aerial vehicle is affected is solved.

Description

Technical Field

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

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

[0003] A significant feature of folding-wing UAVs is their low cost. They can be launched from various platforms, conduct cruise flights in the air, and perform tasks such as intelligence, surveillance, and reconnaissance (ISR), target indication, information relay, area control, air alert, precision strike, and damage assessment after being equipped with different payloads. The takeoff of folding-wing UAVs requires a UAV launcher, which launches the folding-wing UAV to make it take off.

[0004] Current UAV launchers include a launch tube, a piston, and a gas generation device. The gas generation device and the piston are located inside the launch tube. The gas generation device uses solid propellant ignition to generate high-temperature gas, which pushes the piston to move, and then the piston pushes the UAV out of the launch tube to complete the launch.

[0005] There are two types of pistons in current UAV launchers. One is that when launching the UAV, the piston and the UAV fly out of the tube together and separate from the UAV in the air. If the separation is not timely, there is a risk of jamming the UAV's propeller, thus affecting the UAV's takeoff. The other is that when launching the UAV, a connecting mechanism is used to forcibly keep the piston in the launch tube. Although the piston separation problem is solved, the mechanism is complex, the preparation and reloading time is long, and the piston will generate a great impact force when stopping in the tube, causing damage to the launch tube, which is not conducive to cluster launch and secondary launch. The strength of the piston is relatively low and it is prone to being broken. Summary of the Invention

[0006] In order to solve the above problems, the present invention proposes a separable piston device for folding-wing UAV delivery, 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: The present invention proposes a separable piston device for folding-wing UAV delivery, including: 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.

[0008] Furthermore, a sinking space is provided on the lower end surface of the piston, and the parachute can be folded and placed in this sinking space.

[0009] Furthermore, the parachute cords are connected to the eye nuts; the eye nuts are connected to the piston by screws.

[0010] Furthermore, a clamping groove is provided on the upper end surface of the piston.

[0011] Furthermore, the piston is made of engineering plastics.

[0012] Furthermore, the outer peripheral surface of the piston is adapted to the inner wall of the launch tube, and the edges of the piston are rounded off.

[0013] Furthermore, when the piston is located inside the launch tube, the parachute is in a folded state; when the piston disengages from the launch tube and ascends, the parachute unfolds.

[0014] 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 obtained by calculating according to the piston parameter calculation model; wherein, the piston parameter calculation model includes geometric dimension constraints for ensuring that the piston does not rotate inside the launch tube and mechanical constraints for ensuring that the acceleration of the drone during launch meets the requirements.

[0015] Furthermore, the projected area of the parachute is a set area; the set area is obtained by calculating according to the force balance equation after the parachute unfolds.

[0016] Furthermore, the piston is a rectangular body.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: A separable piston device for folding-wing drone launch proposed by the present invention includes 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 unfold. When using this piston device to launch a drone, the piston can be launched out of the launch tube, and when the piston disengages from the launch tube, the parachute opens, increasing the wind resistance of the piston, reducing the flight speed of the piston in the air, enabling the piston to be separated from the tail of the drone in time, so as not to interfere with the drone rotor, and the piston can quickly land to provide a clear airspace environment, effectively reducing the interference to subsequent launched drones. The parachute can also reduce the landing speed of the piston, reduce the impact force between the piston and the ground, improve the service life of the piston, so that the piston can be reloaded into the launch tube for subsequent drone launches.

[0018] Advantages of additional aspects of the present invention will be partially given in the following description, partially will become obvious from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings of the specification, which form a part of the present application, are used to provide a further understanding of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application.

[0020] Figure 1 Schematic diagram of the structure of the piston device and the folding-wing unmanned aerial vehicle disclosed in the embodiment inside the launch tube; Figure 2 Schematic diagram of the folding-wing unmanned aerial vehicle and the piston device disclosed in the embodiment being ejected from the tube; Figure 3 Schematic diagram of the separation of the piston and the unmanned aerial vehicle after the parachute disclosed in the embodiment is opened; Figure 4 Schematic diagram of the parachute of the piston device disclosed in the embodiment being deployed; Figure 5 Schematic diagram of the gap between the piston and the inner wall of the launch tube disclosed in the embodiment; Figure 6 Schematic diagram of the jamming between the piston and the inner wall of the launch tube disclosed in the embodiment; Figure 7 Force distribution diagram of the piston disclosed in the embodiment.

[0021] Wherein: 1. Folding-wing unmanned aerial vehicle, 2. Piston, 3. Parachute, 4. Launch tube, 5. Gas generator, 6. Ring nut, 7. Sinking space. Detailed implementation manners

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0023] It should be noted that the following detailed description is exemplary and is 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 of ordinary skill in the technical field to which the present application belongs.

[0024] It should be noted that the terms used herein are only for describing specific implementation manners 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 "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] In the present invention, terms such as "fixed connection", "connected", "connected to" should be understood in a broad sense, which may mean a fixed connection, an integral connection or a detachable connection; it may be directly connected or indirectly connected through an intermediate medium. For relevant scientific research or technical personnel in this field, the specific meanings of the above terms in the present invention can be determined according to specific circumstances, and it should not be construed as a limitation to the present invention.

[0026] Embodiment 1 In this embodiment, a separable piston device for the launch of a folding-wing unmanned aerial vehicle is disclosed, which can realize the separation of the piston from the unmanned aerial vehicle immediately when the piston is launched out of the launch tube. During loading, the operation is simple, the device is strong and durable, and it can be launched repeatedly for many times to meet the requirements of cluster launch and secondary launch.

[0027] Specifically, a separable piston device for the launch of a folding-wing unmanned aerial vehicle disclosed in this embodiment is as Figures 1-7 shown, and includes: a piston 2 and a parachute 3; the upper end surface of the piston 2 is used to contact the unmanned aerial vehicle; 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.

[0028] The piston 2 of this embodiment is used to be loaded into the launch tube 4 to launch the folding-wing unmanned aerial vehicle 1. When the folding-wing unmanned aerial vehicle 1 is pneumatically catapulted, the piston 2 provides the thrust for the folding-wing unmanned aerial vehicle to exit the tube, and isolates the high-temperature gas generated by the gas generator 5 during the explosion of gunpowder from directly contacting the aircraft, protecting the aircraft from damage.

[0029] By installing the parachute 3 on the lower end surface of the piston 2, during the launch process of the folding-wing unmanned aerial vehicle 1, when the piston 2 is catapulted out of the launch tube 4, the parachute 3 opens, increasing the air resistance of the piston 2, reducing the flight speed of the piston 2 in the air, and enabling the piston 2 to be actively separated from the tail of the unmanned aerial vehicle; the parachute can also reduce the landing speed of the piston and reduce the impact with the ground; it improves the service life of the piston, reduces the flight distance of the piston in the air, and the piston can quickly land to provide a clear airspace environment, effectively reducing the interference to the subsequent launched unmanned aerial vehicles, and the piston can be quickly reloaded to improve the launch efficiency.

[0030] As Figure 4 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.

[0031] Preferably, the parachute shroud lines are connected to the eye nut 6; the eye nut 6 is connected to the piston 2 by screws.

[0032] According to the triangular folding method of the parachute canopy, the parachute shroud lines are folded by the figure-eight winding method. After the shroud lines and the canopy are folded, the parachute 3 can be placed in the sinking space 7 of the piston 2.

[0033] When the piston 2 is located inside the launch tube 4, the parachute 3 is in a folded state; during the process when the piston 2 disengages from the launch tube 4 and ascends, the parachute 3 unfolds.

[0034] A clamping groove is provided on the upper end face of the piston 2; this clamping groove is used to clamp the tail of the unmanned aerial vehicle; this clamping groove can be adjusted according to the shape of the tail of the unmanned aerial vehicle to be launched, so as to meet the launch requirements of different types of unmanned aerial vehicles.

[0035] The piston 2 of this embodiment is made of engineering plastic. Engineering plastic materials have high elasticity, impact resistance, and a relatively small friction coefficient, which can effectively improve the service life of the piston.

[0036] Preferably, the engineering plastic is processed into the piston 2 by means of 3D printing.

[0037] In traditional aircraft launchers, when the piston is pushed by high-pressure gas and moves axially inside the launch tube, it usually deviates from the center of the launch tube and generates deflection, squeezing against the inner wall of the launch tube, generating a large force, resulting in piston jamming and wedging, reducing the launch speed of the unmanned aerial vehicle and causing the launch to fail.

[0038] 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 chamfered to ensure that the piston does not jam when moving inside the launch tube.

[0039] For the separable piston device for folding-wing unmanned aerial vehicle delivery disclosed in this embodiment, before loading it into the launch tube 4, first connect the parachute ropes of the parachute 3 to the eye nut 6 through knots, and fold the parachute canopy according to the triangular parachute folding method, and the parachute ropes are folded by the figure-eight winding method. After the parachute canopy ropes are folded, connect the eye nut 6 to the lower end face of the piston by bolts. Finally, place the parachute canopy ropes in the sunken space 7 on the lower end face of the piston.

[0040] During loading, place the piston 2 into the launch tube 4 from the front of the launch tube, keep the launch tube cylinder at a certain angle, and the piston 2 naturally slides into the bottom of the tube under the action of gravity, contacting the gas generation chamber, thereby closing the top of the gas generation chamber.

[0041] During launch, the gas generator 5 is fired to generate high-temperature gas. Under the action of the high-temperature gas, the piston 2 pushes the folding-wing unmanned aerial vehicle 1 out of the launch tube. When the piston 2 is completely exposed from the launch tube, the parachute 3 quickly inflates and opens under the action of the air, decelerating the piston, thereby achieving active separation.

[0042] The separable piston device disclosed in this embodiment actively decelerates by deploying a parachute after the piston exits the barrel, enabling the piston to quickly separate from the tail of the drone. The parachute can also reduce the piston's ground contact speed and flight distance. On the one hand, it improves the piston's service life. On the other hand, the parachute also reduces the piston's flight distance, and during cluster launches, it can quickly provide a clear sky environment and effectively reduce interference with subsequent launched drones.

[0043] To ensure that the piston 2 does not get stuck during its movement in the launch barrel, the volume of the piston in this embodiment is defined as a set volume, and the mass of the piston is defined as a set mass; the set volume and set mass are obtained by calculating according to the piston parameter calculation model; among them, the piston parameter calculation model includes geometric dimension constraints to ensure that the piston does not rotate in the launch barrel and mechanical constraints to ensure that the acceleration of the drone during launch meets the requirements.

[0044] Specifically, the set volume and set mass are obtained by calculating according to the fillet radius at the edge of the piston, the rotation angle of the piston when it gets stuck with the launch barrel, the erection angle of the launch barrel, the launch gas pressure, the clearance between the piston and the inner wall of the launch barrel, the piston height, and the piston parameter calculation model.

[0045] Preferably, the piston is a rectangular body. Preferably, the rectangular body is a cuboid. Taking the cuboid piston as an example, the piston parameter calculation model will be described in detail.

[0046] For a cuboid piston, the height direction of the piston is consistent with the axial direction of the launch barrel. When the diagonal of the side surface of the piston is greater than the side length of the inner wall of the launch barrel, it can be ensured that the piston does not rotate in the launch barrel due to dimensional constraints. Among them, the side surface of the piston refers to the plane other than the upper and lower end faces of the piston. Therefore, the geometric dimension constraints to ensure that the piston does not rotate in the launch barrel can be expressed as: h 2 +( L - x ) 2 > L 2 ; In the formula, L is the side length of the inner wall of the launch barrel, x is the clearance between the piston and the inner wall of the launch barrel, h is the piston height, and this piston height refers to the distance between the upper and lower end faces of the piston.

[0047] During application, to avoid stress concentration, the edge of the piston is processed with a fillet. Let the radius of the fillet at the edge of the piston be R, assuming that the piston jams with the launcher tube, when the piston jams with the launcher tube, the chamfered corner at the edge of the piston is tangent to the inner wall of the launcher tube. At this time, the piston rotates from being parallel to the corresponding surfaces of the inner wall of the launcher tube on all sides to jamming with the launcher tube, and the rotation angle of the piston is α. When launching the UAV, the erection angle of the launcher tube is β, satisfying the geometric relationship conditions: L = ( L - x - 2R) cosα + ( h - 2R) sinα + 2R; L = A1B = A1R1 + R1D + CD + BC; R1D = (L - x - 2R) cosα; CD = ( h - 2R) sinα; In the formula, 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, BC is the distance between point B and point C, as Figure 5 , Figure 6 shown, Figure 5 is a schematic diagram of the clearance between the piston and the inner wall of the launcher tube, Figure 6 is a schematic diagram of the piston jamming with the inner wall of the launcher tube after deflection in the launcher tube. In the figure, point A1 and point A2 are two tangent points between the piston and the inner wall of the launcher tube; point R1, point R2, point R3 and point R4 are the centers of the chamfered corners at the two opposite edges of the lower end face of the piston and the centers of the chamfered corners at the two opposite edges of the upper end face of the piston. These four edges are four parallel edges, and these four edges include the edge where the piston is tangent to the inner wall of the launcher 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. Point R1, point R2, point R3, point R4, point A1 and point A2 are in the same plane, and this plane is parallel to the other two inner walls of the launcher tube. The other two inner walls of the launcher tube are the inner walls that are not tangent to the piston; point B is the intersection point of the extension line of the connection line between point A1 and point R1 and the inner wall of the launcher tube, point C is the projection of point R3 on the connection line between point A1 and point B, that is, the connection line between point R3 and point C is perpendicular to the connection line between point A1 and point B; point E is the intersection point of the extension line of the connection line between point A2 and point R3 and the connection line between point R4 and point R1, point D is the intersection point of the connection line between point E and point R2 and the connection line between point A1 and point B, A1R1 is equal to the chamfered corner radius R, and BC is equal to the chamfered corner radius R.

[0048] When the gas generator fires, high-temperature gas is generated to push the piston. When the critical jamming state occurs, the friction between the piston and the launcher tube increases. From the geometric relationship, it can be known that when the critical jamming state occurs, the normal pressure at point A1 N1' increases to the normal pressure at point A1 without jamming N by sinα times of 1, that is: N 1 = m 活塞 gcosβ; N 1' = (1 + sinα) N 1 = (1 + sinα)m 活塞 gcosβ; As Figure 7 shown, due to the jamming between the piston and the inner wall of the launch tube, a new frictional force is generated at point A2, and at the same time, a new support force is added to the inner wall of the launch tube, and this support force is equal to the normal pressure at point A2 N 2. At this time, the frictional force at point A2 is μ N 2, N 2 is equal to N 1', then: N 2 = (1 + sinα) N 1 = (1 + sinα)m 活塞 gcosβ; In this state, if the acceleration of the UAV is to meet the requirements, then there is: High-temperature gas pressure (P·S) - system frictional loss (μ N ) ≥ (UAV mass + piston mass) × acceleration, where N is the normal pressure at point A1 when the critical jamming state occurs N 1' and the normal pressure at point A2 N 2, that is, the mechanical constraint condition to ensure that the acceleration of the UAV meets the requirements during the launch process can be expressed as: PS - μ( N 1' + N 2) ≥ (m 无人机 + m 活塞 )a; In the formula, P is the high-temperature gas pressure generated by the gas launcher, that is, the launch gas pressure, S is the pressure area, when jamming occurs, it can be approximately the cross-sectional area of the inner tube of the launch tube, that is, S = L 2 , a is the acceleration of the UAV.

[0049] Therefore, when determining the set volume and set mass of the piston in this embodiment, according to the initially determined UAV mass m 无人机 , the fillet radius R at the edge of the piston, the rotation angle α of the piston when jamming occurs with the launch tube, the erection angle β of the launch tube, the launch gas pressure P, the inner wall side length of the launch tube L and the above formula, the clearance between the piston and the inner wall of the launch tube x and the piston height hWith the piston mass m 活塞 , according to the gap between the piston and the inner wall of the launch tube x and the side length of the inner wall of the launch tube L , the side length of the piston is calculated, where the side length of the piston is equal to the side length of the inner wall of the launch tube L minus the gap between the piston and the inner wall of the launch tube x ; According to the side length of the piston and the piston height h , the piston volume V is calculated; this piston volume and piston mass are the set volume and set mass of the piston.

[0050] In this embodiment, in order to prevent the piston from being damaged by hitting the ground after descending to the ground, the projected area of the parachute is limited to a set area; the set area is obtained by calculating according to the force balance equation after the parachute is deployed.

[0051] Specifically, in this embodiment, in order to prevent the piston from being damaged by hitting the ground after descending to the ground, the descending speed after the parachute is deployed is limited, and it is limited that the descending speed after the parachute is deployed is less than or equal to the set speed, and the set speed can be 5 m / s.

[0052] The projected area D of the parachute can be calculated by the parachute tension equation. When the gravity of the load is equal to the parachute tension, the parachute descends at a constant speed. Then the force balance equation after the parachute is deployed can be expressed as: ; In the formula, F is the parachute tension, that is, the required resistance, and this tension can be approximately calculated using the gravity m·g of the load. Here, m is the piston mass and g is the acceleration due to gravity; C d is the air resistance coefficient, which is determined according to 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 descending speed; the air resistance coefficient C d can be determined by wind tunnel tests or numerical simulations. For parachutes of different shapes, the resistance coefficient will be different. For example, the resistance coefficient of a sphere is about 0.5, while that of a square is 1.

[0053] Once the resistance coefficient, descending speed, and parachute tension F are determined, the projected area of the parachute can be calculated by the following formula: ; The projected area D calculated by the above formula is the set area.

[0054] The separable piston device proposed in this embodiment can effectively prevent piston jamming by limiting the mass and volume of the piston and the projected area of the parachute, and can effectively ensure low-velocity descent after the parachute is deployed, thereby reducing the collision force when the piston touches the ground, preventing the piston from being damaged, and increasing the service life of the piston.

[0055] Although the specific implementation mode of the present invention is described above in conjunction with the drawings, it is not a limitation on the protection scope of the present invention. Those skilled in the art should understand that, based on the technical solution of the present invention, various modifications or deformations that can be made by those skilled in the art without creative labor are still within the protection scope 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.

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

3. A separate piston device for launching a folding-wing UAV as claimed in claim 1, characterized in that: The parachute line is connected to the eye nut; the eye nut is connected to the piston via a screw.

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

5. A separate piston device for launching a folding-wing UAV as claimed in claim 1, characterized in that: The piston is made of fiberglass.

6. A separate piston device for launching a folding-wing UAV as claimed in claim 1, characterized in that: The outer peripheral surface of the piston is matched with the inner wall of the launching tube, and each edge of the piston is chamfered.

7. A separate piston device for launching a folding-wing UAV as claimed in claim 6, 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 rises, the parachute is unfolded.

8. A separate piston device for launching a folding-wing UAV as claimed in claim 6, characterized in that: The volume of the piston is the set volume, and the mass of the piston is the set mass; the set volume and the set mass are calculated according to 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.

9. A separate piston device for launching a folding-wing UAV as claimed in claim 1, characterized in that: The projection area of ​​the parachute is the set area; the set area is calculated based on the force balance equation after the parachute is deployed.

10. A separate 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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