An omnidirectional anti-crash unmanned aerial vehicle with a series multi-stage composite buffer structure

Abstract

This invention relates to the field of unmanned aerial vehicle (UAV) technology, specifically to an omnidirectional crash-resistant UAV with a series multi-level composite buffer structure. The UAV includes a flight control platform with a cargo box connected to its bottom. Support frames are connected to both sides of the cargo box, and rotors are mounted on the top of each support frame. Each support frame includes an X-shaped mounting bracket with two upper extensions and two lower extensions, the upper extensions being located above the lower extensions. The rotors are connected to each upper extension, and ground-contact pads are connected to each lower extension. An upper shock-absorbing buffer device is positioned between the upper extensions and the rotors. This invention utilizes the upper shock-absorbing buffer device on the upper extensions to absorb and buffer the powerful impact energy from the ground when the UAV contacts the ground, thereby protecting valuable onboard equipment and cargo.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle technology, and specifically to an omnidirectional crash-resistant unmanned aerial vehicle with a series multi-level composite buffer structure. Background Technology

[0002] With the rapid development of the low-altitude economy, drones have become the core of urban low-altitude logistics and emergency support systems due to their core advantages such as flexible operation, less restriction by terrain, high transportation efficiency, and ability to avoid traffic congestion. They have broad application prospects in scenarios such as emergency material transportation in mountainous / disaster areas and cargo transportation in remote areas, and are of great significance for improving logistics efficiency and expanding the boundaries of emergency support.

[0003] However, in actual large-scale application, existing cargo drones still have significant technical shortcomings and safety hazards: First, the design of existing cargo drones focuses on flight control stability and endurance under normal flight conditions, and the protection design for sudden crash scenarios such as power system failure and obstacle avoidance system failure is insufficient; Second, existing buffer structures are mostly only deployed at the bottom of the fuselage, which can only adapt to the single protection scenario of vertical fall, and cannot effectively protect against multi-directional impacts; Third, the cargo boxes of existing cargo drones are mostly fixed-size integrated designs, which cannot be flexibly adjusted and adapted according to the size, weight and type of the transported goods, making it difficult to meet diverse cargo transportation needs. Summary of the Invention

[0004] In response to the numerous shortcomings of the existing technologies, this invention proposes an omnidirectional crash-resistant buffer drone, which systematically solves the core technical problems of insufficient crash protection, multi-directional buffering, and poor cargo box adaptability of existing cargo drones.

[0005] The present invention provides an omnidirectional crash-resistant unmanned aerial vehicle with a series multi-level composite buffer structure, including a flight control platform. The bottom of the flight control platform is connected to a cargo box, and support frames are connected to both sides of the cargo box. A rotor is provided at the top of the support frame. The support frame includes an X-shaped fixed frame, and the X-shaped fixed frame is provided with two upper protruding ends and two lower protruding ends. The upper protruding ends are located above the lower protruding ends. The upper protruding end is connected to the rotor, and the lower protruding end is connected to the ground contact pad. An upper shock-absorbing and buffering device is provided between the upper protruding end and the rotor. The upper shock-absorbing and buffering device includes an upper buffer cylinder and an upper piston rod. One end of the upper buffer cylinder is fixedly connected to the upper protruding end, and an upper cylinder chamber is provided on the other end of the upper buffer cylinder. An upper elastic shock-absorbing device is fixedly connected to the end of the upper cylinder chamber near the upper protruding end. An upper piston rod is matched and provided in the upper cylinder chamber. One end of the upper piston rod extends out of the upper cylinder chamber and is connected to the rotor. The upper cylinder chamber includes a conical chamber and a cylindrical chamber located near the upper protruding end. The end of the conical chamber with the larger inner diameter is connected to and communicates with the cylindrical chamber. The end of the upper piston rod that extends into the upper cylinder chamber is also conical. The end of the upper elastic damping device that is away from the upper protruding end abuts against the end of the upper piston rod.

[0006] Preferably, at least two upper shock-absorbing buffer devices are provided between the upper protruding end and the rotor, and the upper shock-absorbing buffer devices are connected in sequence to form a composite upper shock-absorbing buffer device. One end of the composite upper shock-absorbing and buffering device is fixedly connected to the upper protruding end, and the other end of the composite upper shock-absorbing and buffering device is connected to the rotor. Of the two adjacent upper shock-absorbing devices, the one closer to the upper protruding end is the first upper shock-absorbing device, and the other upper shock-absorbing device is the second upper shock-absorbing device. The upper piston rod of the second upper shock-absorbing device extends into the upper cylinder chamber of the first upper shock-absorbing device and abuts against the upper elastic buffer device in the upper cylinder chamber of the first upper shock-absorbing device. The upper piston rod of the second upper shock-absorbing device is matched and connected to the upper cylinder chamber of the first upper shock-absorbing device.

[0007] Preferably, a lower shock-absorbing buffer device is provided between the lower protruding end and the ground contact pad; The lower shock absorption device includes a lower buffer cylinder and a lower piston rod. One end of the lower buffer cylinder is fixedly connected to the lower extension end. A lower cylinder chamber is provided on the other end of the lower buffer cylinder. A lower elastic shock absorption device is fixedly connected to the lower cylinder chamber near the lower extension end. A lower piston rod is matched and provided in the lower cylinder chamber. One end of the lower piston rod extends out of the lower cylinder chamber and is connected to the ground contact pad. The lower cylinder chamber includes a conical chamber and a cylindrical chamber located near the lower extension end. The end of the conical chamber with the larger inner diameter is connected to and communicates with the cylindrical chamber. The end of the lower piston rod that extends into the lower cylinder chamber is also conical. The end of the lower elastic damping device that is away from the lower extension end abuts against the end of the lower piston rod.

[0008] Preferably, at least two lower shock-absorbing buffer devices are provided between the lower protruding end and the ground contact pad, and the lower shock-absorbing buffer devices are connected in sequence to form a composite lower shock-absorbing buffer device; One end of the composite lower shock absorber is fixedly connected to the lower protruding end, and the other end of the composite lower shock absorber is connected to the ground contact pad. Of the two adjacent lower shock absorber devices, the one closer to the lower extension end is the first lower shock absorber device, and the other is the second lower shock absorber device. The lower piston rod of the second lower shock absorber device extends into the lower cylinder chamber of the first lower shock absorber device and abuts against the lower elastic buffer device in the lower cylinder chamber of the first lower shock absorber device. The lower piston rod of the second lower shock absorber device is matched and connected to the lower cylinder chamber of the first lower shock absorber device.

[0009] Preferably, both the upper elastic damping device and the lower elastic damping device are damping springs; The central axes of the damping springs in the same composite upper or lower damping device are located on the same straight line. Both the upper and lower cylinder chambers have a limiting ring platform at the end of the cylindrical chamber away from the conical chamber to prevent the upper or lower piston rod from dislodging. The diameter of the upper or lower piston rod located in the upper or lower cylinder chamber near the limiting ring is not less than the inner diameter of the limiting ring.

[0010] Preferably, the upper cylinder chamber and the upper piston rod extending into the upper cylinder chamber are in clearance fit; The depth of the cylindrical chamber of the upper cylinder is not greater than the maximum stroke of the upper elastic damping device when compressed. The lower cylinder chamber and the lower piston rod extending into the lower cylinder chamber are also clearance fit; The depth of the cylindrical chamber of the lower cylinder is not greater than the maximum stroke of the lower elastic damping device under compression.

[0011] Preferably, the upper buffer cylinder is provided with an upper air inlet and an upper air outlet, the upper air inlet is provided with an upper air inlet one-way valve, and both the upper air inlet and the upper air outlet are connected to the upper cylinder chamber. An upper throttling vent valve is provided on the upper exhaust port.

[0012] Preferably, the lower buffer cylinder is provided with a lower air inlet and a lower air outlet, the lower air inlet is provided with a lower air inlet one-way valve, and both the lower air inlet and the lower air outlet are connected to the lower cylinder chamber; A lower throttling vent valve is provided on the lower exhaust port.

[0013] Preferably, a rubber cushioning airbag is fixedly connected to the ground mat. The rubber cushioning airbag is fixedly connected to one end of the ground mat via a mounting base and a lower piston rod. The rubber cushioning airbag is equipped with an inflation one-way valve.

[0014] Preferably, the cargo box has a double-layer impact-resistant structure, including an outer carbon fiber protective shell and an inner cushioning liner, with honeycomb cushioning material filling the space between the inner cushioning liner and the outer carbon fiber protective shell. The top of the cargo box is equipped with a docking plate, which is fixedly connected to the flight control platform through multiple matching quick-connect locking slots and quick-connect locks; The bottom of the cargo box is fixedly equipped with a bottom auxiliary cushioning pad; The cargo box is fixedly connected to the X-shaped mounting frame.

[0015] This invention utilizes an upper shock-absorbing buffer device installed on the upper protruding end to absorb and buffer the powerful impact energy from the ground when the UAV contacts the ground, thereby protecting the valuable airborne equipment and cargo.

[0016] This invention utilizes a composite upper shock-absorbing buffer device formed by connecting at least two upper shock-absorbing buffer devices in sequence to achieve shock absorption and buffering effect, further improving the buffering effect; at the same time, the combination with the upper elastic shock-absorbing device further enhances the buffering effect, significantly improving the shock resistance of the drone during landing or improving the survival guarantee capability of the drone during crash.

[0017] This invention uses a series of internal shock-absorbing springs to absorb the destructive energy generated by the aircraft impacting the ground. When all the shock-absorbing springs are compressed to their limits and still insufficient to absorb all the impact energy, the piston rods of all the sequentially connected shock-absorbing buffer devices begin to simultaneously squeeze the buffer cylinders. By simultaneously crushing multiple sequentially connected buffer cylinders, the powerful ground impact energy is absorbed to the maximum extent. This achieves the most efficient energy absorption and buffering effect while ensuring a lightweight design, thereby protecting valuable airborne equipment and cargo. In the future, the drone equipment can be reused by simply replacing low-cost parts such as buffer cylinders and rotor blades.

[0018] The X-shaped fixed frame structure design of this invention can ensure that when a UAV falls to the ground in any posture and impacts the ground, at least one shock-absorbing and buffering device will impact the ground and trigger the shock-absorbing protection mechanism.

[0019] This invention enables crash protection: the entire drone is equipped with 8 sets of buffer devices to form a three-dimensional spatial protection network, which can ensure that when the drone falls to the ground in any posture (vertical, sideways, upturned, or oblique), at least one set of buffer devices will first contact the impact surface and trigger the shock absorption protection mechanism, thus solving the shortcomings of traditional drones that can only protect against vertical falls and have insufficient multi-directional collision protection capabilities.

[0020] The series-connected multi-stage composite buffer energy absorption system of this invention features an innovative three-stage energy absorption structure consisting of "elastic rubber buffer + return spring pre-buffer + conical surface compression buffer". Compared with a single spring or a single pneumatic buffer, the energy absorption efficiency is greatly improved, achieving a smooth attenuation of impact load and avoiding damage to the fuselage structure from rigid impacts.

[0021] This invention adopts a modular and universal design: the spacing between the two sets of X-shaped fixing frames can be flexibly adjusted through the adjustable connection unit to adapt to different specifications of cargo boxes; the components (springs, cylinders) of the shock absorption and buffer device have the same structure and can be interchanged according to different situations, enabling a rapid response to diverse cargo transportation needs.

[0022] This invention boasts extremely high repairability and very low maintenance costs: the buffer system adopts a modular design, with the buffer cylinder, shock-absorbing spring, and rubber buffer airbag all being standardized, easily damaged parts. After the impact, the return spring can automatically push the buffer device back to its original position. In the event of a crash, only the plastically deformed buffer cylinder and the damaged rubber buffer airbag need to be replaced to restore the drone to its original use, eliminating the need for complete disposal and significantly improving the reusability of the drone.

[0023] This invention can combine active and passive protection: the buffer system can be linked with the flight control system. When the flight control system detects a crash risk, it can adjust the fuselage attitude in advance so that the bottom with the strongest buffer capacity faces the impact surface, so that the buffer system is in the best working state and further improves the crash resistance effect. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall assembly structure of the present invention.

[0025] Figure 2 This is a schematic diagram showing the connection between the rubber buffer airbag and the lower shock-absorbing buffer device of the present invention.

[0026] Figure 3 This is a schematic diagram showing the connection between the rotor and the upper shock-absorbing buffer device of the present invention.

[0027] Figure 4 This is a schematic diagram of an X-shaped fixing frame structure.

[0028] Figure 5 This is a schematic diagram of the connection unit in an embodiment of the present invention.

[0029] Figure 6 This is a schematic diagram of the cargo box of the present invention.

[0030] Figure 7 This is a schematic diagram of the composite upper shock absorption and buffer device.

[0031] Figure 8 This is a schematic diagram of the flight control platform in an embodiment of the present invention.

[0032] Reference numerals: 1-Flight control platform, 2-Cargo box, 3-X-type mounting bracket, 4-Rotor, 5-Upper shock absorber, 6-Rubber shock absorber airbag, 7-Lower shock absorber, 8-Connecting plate, 9-Lower shock absorber cylinder, 10-Lower piston rod, 11-Upper shock absorber cylinder, 12-Upper piston rod, 13-U-shaped slide rail, 14-Slide seat, 15-Ground contact pad, 16-Rectangular groove, 17-First upper shock absorber, 18-Second upper shock absorber, 19-Upper cylinder chamber, 20-Shock absorber spring. Detailed Implementation

[0033] The present invention will be described below with reference to the accompanying drawings.

[0034] See Figure 1-8 As shown in Embodiment 1, an omnidirectional crash-resistant unmanned aerial vehicle (UAV) with a series multi-level composite buffer structure includes a flight control platform 1. The top of the flight control platform 1 integrates a controller, communicator, ultrasonic sensor, power supply, and various sensing sensors. Support frames are symmetrically arranged on both sides of the flight control platform 1. These support frames are X-shaped fixed frames 3, with their four extended ends respectively fixedly connected to two composite upper shock-absorbing buffer devices and two composite lower shock-absorbing buffer devices. The top of the composite upper shock-absorbing buffer device is equipped with a rotor 4, a drive motor, and a planetary reducer, while the bottom of the composite lower shock-absorbing buffer device is equipped with a rubber buffer airbag 6. A double-layered cargo box 2 is installed at the bottom of the flight control platform 1. The two sides of the cargo box 2 are assisted in locking by fixing structural components. In one embodiment, the fixing structural components can be four long connecting bolts inserted into the middle of the X-shaped fixed frame 3. After selecting the cargo box 2, the distance between the two X-shaped fixed frames 3 is adjusted, and the X-shaped fixed frames 3 are fixed to the corresponding bolt holes on both sides of the cargo box 2 through the four connecting bolts, thus assisting in locking. The drone is equipped with four composite upper shock-absorbing buffer devices and four composite lower shock-absorbing buffer devices, forming an all-directional buffer protection system covering the upper, lower, left, and right sides of the fuselage. At the same time, the modular cargo box 2 design adapts to diverse transportation needs.

[0035] In one embodiment, a lower shock-absorbing buffer device is provided between the lower protruding end and the ground contact pad 15; The lower shock absorption device includes a lower buffer cylinder 9 and a lower piston rod 10. One end of the lower buffer cylinder 9 is fixedly connected to the lower extension end. A lower cylinder chamber is provided on the other end of the lower buffer cylinder 9. A lower elastic shock absorption device is fixedly connected to the lower cylinder chamber near the lower extension end. A lower piston rod 10 is matched and provided in the lower cylinder chamber. One end of the lower piston rod 10 extends out of the lower cylinder chamber and is connected to the ground contact pad 15. The lower cylinder chamber includes a conical chamber and a cylindrical chamber located near the lower extension end. The end of the conical chamber with the larger inner diameter is connected to and communicates with the cylindrical chamber. The end of the lower piston rod 10 that extends into the lower cylinder chamber is also conical. The end of the lower elastic damping device that is away from the lower extension end abuts against the end of the lower piston rod 10.

[0036] At least two lower shock-absorbing buffer devices 7 are provided between the lower protruding end and the ground contact pad 15, and the lower shock-absorbing buffer devices 7 are connected in sequence to form a composite lower shock-absorbing buffer device. In one embodiment, an upper shock-absorbing device is provided between the upper protruding end and the rotor 4. The upper shock-absorbing device includes an upper buffer cylinder 11 and an upper piston rod 12. One end of the upper buffer cylinder 11 is fixedly connected to the upper protruding end, and an upper cylinder chamber is provided on the other end of the upper buffer cylinder 11. An upper elastic shock-absorbing device is fixedly connected to the end of the upper cylinder chamber near the upper protruding end. An upper piston rod 12 is matched and provided in the upper cylinder chamber. One end of the upper piston rod 12 extends out of the upper cylinder chamber and is connected to the rotor 4. The upper cylinder chamber includes a conical chamber and a cylindrical chamber located near the upper protruding end. The end of the conical chamber with the larger inner diameter is connected to and communicates with the cylindrical chamber. The end of the upper piston rod 12 that extends into the upper cylinder chamber is also conical. The end of the upper elastic damping device that is away from the upper protruding end abuts against the end of the upper piston rod.

[0037] As needed, it can be configured as follows: at least two upper shock-absorbing buffer devices 5 are provided between the upper extension end and the rotor 4, and the upper shock-absorbing buffer devices 5 are connected in sequence to form a composite upper shock-absorbing buffer device.

[0038] Example 2, the structure of the composite upper shock absorption and buffer device is as follows: Figure 2 As shown, from bottom to top, the components are: the buffer cylinder of the first upper shock absorber 17, the buffer cylinder of the second upper shock absorber 18, and the upper piston rod connected to the rotor 4. One end of the buffer cylinder of the second upper shock absorber 18 extends into the upper cylinder chamber 19 of the buffer cylinder of the first lower shock absorber 7, acting as a piston rod to form a second set of conical buffer units. The other end of the buffer cylinder of the second upper shock absorber 18 and the upper piston rod form a first set of conical buffer units. The end of the upper cylinder chamber 19 of the first upper shock absorber 17 is provided with a limiting ring to prevent the second upper shock absorber 18 from disengaging from the upper cylinder chamber 19 of the first lower shock absorber 7. An air inlet is provided on the side wall of the buffer cylinder of the first upper shock absorber 17, and an air inlet one-way valve is installed. Throttling and venting valves are installed on the top of the buffer cylinder of the first upper shock absorber 17 and the top of the buffer cylinder of the second upper shock absorber 18, so that the exhaust rate can be adjusted to achieve dynamic adjustment of the buffer stiffness.

[0039] Both the upper shock-absorbing buffer device 5 and the lower shock-absorbing buffer device 7 are equipped with shock-absorbing springs 20 in the cylinder chamber. In the same set of conical buffer units, the two ends of the shock-absorbing springs 20 abut against the cylinder chamber and the piston rod end, respectively. When there is no external force, the damping spring 20 pushes the piston rod to its maximum extension state. After the impact disappears, it drives the composite upper damping buffer device or the composite lower damping buffer device to automatically reset.

[0040] In Example 3, the four protruding ends of the X-shaped fixing frame 3 are all fixedly connected to the upper shock-absorbing buffer device 5 or the lower shock-absorbing buffer device 7 by threads to prevent rotation or axial movement. The X-shaped fixing frame 3 has a fixing hole for the cargo box 2 in the center and is rigidly connected to the side wall of the cargo box 2 by radial screws.

[0041] Example 4: The connecting unit is used to connect the flight control platform 1 and the X-shaped mounting bracket 3. The connecting unit includes two parallel high-strength U-shaped slide rails 13 and two sets of slide blocks 14. Two parallel square grooves are milled along the length direction on both sides of the flight control platform 1 to install the slide blocks 14 of the U-shaped slide rails 13. Part of the U-shaped slide rail 13 is embedded in the slide block 14, and the other part extends toward the X-shaped mounting bracket 3 and is fixedly connected to the connecting plate 8 fixed between the two upper protruding ends on the X-shaped mounting bracket 3 by bolts.

[0042] After adjusting the distance between the two sets of fixed frames, the U-shaped slide rail 13 can be locked in the corresponding position by connecting it to the corresponding hole on the flight control platform 1, so as to flexibly adjust the distance between the two sets of X-shaped fixed frames 3 to adapt to different specifications of cargo boxes 2.

[0043] In Example 5, the flight control platform 1 is milled from T700 carbon fiber high-strength plate and has an overall rectangular structure. Its top surface is divided into a standardized equipment installation area and a rectangular groove 16 for mounting the slide block 14 of the U-shaped slide rail 13, and bolt holes are provided for fixing and installing control system, power supply, communication device and sensor and other equipment by hexagonal bolts. At the same time, all electronic equipment and flight control platform 1 are padded with 1mm thick silicone rubber shock-absorbing pads, which can isolate the transmission of rotor 4 vibration to core electronic components and improve flight control stability. The bottom surface of flight control platform 1 is vertically provided with four docking positioning pins arranged in a rectangular array for quick and accurate positioning when installing with cargo box 2 to prevent cargo box 2 from moving laterally.

[0044] The quick-connect lock is a spring-type quick-connect lock in the prior art, which mainly consists of a locking tongue, a return spring, a pressing button and a housing; the spring-type quick-connect locks are symmetrically arranged on the outside of the four positioning pins at the bottom of the flight control platform 1, and the quick-connect lock slots for accommodating the spring-type quick-connect locks are opened on the outside of the four upwardly protruding cross bosses at the top of the cargo box 2 and are flush with the inward pressing direction of the quick-connect locks at the bottom of the flight control platform 1.

[0045] In Example 6, the cargo box 2 has a double-layer impact-resistant structure, including an outer carbon fiber protective shell and an inner cushioning pad, with aluminum honeycomb material filling the space between the inner cushioning pad and the outer carbon fiber protective shell. The top of the cargo box 2 has positioning holes adapted to the positioning pins and quick-release locks; the middle of both side walls has connection holes for connecting the X-shaped fixing bracket 3; and the bottom is equipped with a rubber auxiliary cushioning pad.

[0046] In Example 7, the rotor 4 drive motor is mounted on the top of the upper piston rod via a silicone rubber shock absorber. The output shaft of the rotor 4 drive motor is splinedly connected to the input end of the planetary reducer, and the output end of the reducer is fixed to the rotor 4. A flexible silicone rubber shell is fitted over the rotor 4 drive and reducer to provide initial cushioning in the event of a side or overhead impact on the rotor 4. The bottom of the rubber cushioning airbag 6 is connected to a rubber wear-resistant ground contact pad 15 with anti-slip patterns on the surface to increase ground friction and disperse impact force.

[0047] The working principle and usage process of this invention are as follows: Before transportation, select a cargo box 2 with appropriate specifications according to the size and weight of the goods to be transported, and load the goods into the cargo box 2; adjust the distance between the two sets of fixing devices by extending the U-shaped slide rail in the connecting unit to match the length of the cargo box 2, and then lock the slide rail through the bolt holes corresponding to the flight control platform 1 with bolts to fix the position; align the positioning hole on the top of the cargo box 2 with the positioning pin on the bottom of the flight control platform 1 for fixing, then lock the quick-locking tongue, and finally lock the side wall of the cargo box 2 to the fixing hole of the fixing device with the fastening bolts to complete the double fixing of the cargo box 2.

[0048] During flight, various sensors, ultrasonic radar, and cameras are installed to collect data in real time and control the rotor system to complete the flight path. The X-shaped shock absorption and buffer device also provides protection for the fuselage.

[0049] When a drone collides or crashes, the buffer system absorbs energy in three stages: First-stage elastic buffering phase: When the bottom falls vertically to the ground, the rubber buffer airbag 6 first undergoes large deformation to absorb the initial impact energy; when the rotor 4 is hit from the side or up, the flexible silicone rubber shell first deforms to absorb energy, while the blade breaks to unload the impact, and the synchronously compressed shock-absorbing spring 20 absorbs the impact energy and attenuates the initial peak impact force.

[0050] Secondary aerodynamic buffering stage: When the impact energy exceeds the primary load-bearing limit, the upper shock-absorbing buffer device 5 and / or the lower shock-absorbing buffer device 7 begin to contract, continuing to compress the shock-absorbing spring 20 while simultaneously squeezing the buffer cylinder, continuing to absorb the remaining impact energy to achieve smooth deceleration of the fuselage and avoid rigid impact. After the impact, the shock-absorbing spring 20 pushes the buffer cylinder and piston rod to automatically reset; if the buffer cylinder, flight control platform 1, and cargo box 2 are not structurally damaged, only the rubber buffer airbag 6 needs to be replaced and re-inflated, and the UAV can be put back into use.

[0051] When the composite upper shock-absorbing device and the composite lower shock-absorbing device fail, there is still residual impact. At this time, cargo box 2 enters the protection stage: the residual impact load is transferred to cargo box 2, the outer carbon fiber resists the impact, and the middle aluminum honeycomb layer absorbs energy further through controllable plastic deformation, ultimately meeting the protection requirements for civilian goods.

Claims

1. An omnidirectional crash-resistant unmanned aerial vehicle (UAV) with a series multi-level composite buffer structure, comprising a flight control platform, a cargo box connected to the bottom of the flight control platform, support frames connected to corresponding sides of the cargo box, and a rotor mounted on the top of the support frames, characterized in that, The support frame includes an X-shaped fixing frame, which has two upper protruding ends and two lower protruding ends, with the upper protruding ends located above the lower protruding ends; The upper protruding end is connected to the rotor, and the lower protruding end is connected to the ground contact pad. An upper shock-absorbing and buffering device is provided between the upper protruding end and the rotor. The upper shock-absorbing and buffering device includes an upper buffer cylinder and an upper piston rod. One end of the upper buffer cylinder is fixedly connected to the upper protruding end, and an upper cylinder chamber is provided on the other end of the upper buffer cylinder. An upper elastic shock-absorbing device is fixedly connected to the end of the upper cylinder chamber near the upper protruding end. An upper piston rod is matched and provided in the upper cylinder chamber. One end of the upper piston rod extends out of the upper cylinder chamber and is connected to the rotor. The upper cylinder chamber includes a conical chamber and a cylindrical chamber located near the upper protruding end. The end of the conical chamber with the larger inner diameter is connected to and communicates with the cylindrical chamber. The end of the upper piston rod that extends into the upper cylinder chamber is also conical. The end of the upper elastic damping device that is away from the upper protruding end abuts against the end of the upper piston rod.

2. The omnidirectional crash-resistant UAV with a series multi-level composite buffer structure as described in claim 1, characterized in that, At least two upper shock-absorbing devices are provided between the upper protruding end and the rotor, and the upper shock-absorbing devices are connected in sequence to form a composite upper shock-absorbing device. One end of the composite upper shock-absorbing and buffering device is fixedly connected to the upper protruding end, and the other end of the composite upper shock-absorbing and buffering device is connected to the rotor. Of the two adjacent upper shock-absorbing devices, the one closer to the upper protruding end is the first upper shock-absorbing device, and the other upper shock-absorbing device is the second upper shock-absorbing device. The upper piston rod of the second upper shock-absorbing device extends into the upper cylinder chamber of the first upper shock-absorbing device and abuts against the upper elastic buffer device in the upper cylinder chamber of the first upper shock-absorbing device. The upper piston rod of the second upper shock-absorbing device is matched and connected to the upper cylinder chamber of the first upper shock-absorbing device.

3. The omnidirectional crash-resistant UAV with a series multi-level composite buffer structure as described in claim 1, characterized in that, A lower shock-absorbing buffer device is provided between the lower protruding end and the ground contact pad; The lower shock absorption device includes a lower buffer cylinder and a lower piston rod. One end of the lower buffer cylinder is fixedly connected to the lower extension end. A lower cylinder chamber is provided on the other end of the lower buffer cylinder. A lower elastic shock absorption device is fixedly connected to the lower cylinder chamber near the lower extension end. A lower piston rod is matched and provided in the lower cylinder chamber. One end of the lower piston rod extends out of the lower cylinder chamber and is connected to the ground contact pad. The lower cylinder chamber includes a conical chamber and a cylindrical chamber located near the lower extension end. The end of the conical chamber with the larger inner diameter is connected to and communicates with the cylindrical chamber. The end of the lower piston rod that extends into the lower cylinder chamber is also conical. The end of the lower elastic damping device that is away from the lower extension end abuts against the end of the lower piston rod.

4. The omnidirectional crash-resistant UAV with a series multi-level composite buffer structure as described in claim 3, characterized in that, At least two lower shock-absorbing devices are provided between the lower protruding end and the ground contact pad, and the lower shock-absorbing devices are connected in sequence to form a composite lower shock-absorbing device. One end of the composite lower shock absorber is fixedly connected to the lower protruding end, and the other end of the composite lower shock absorber is connected to the ground contact pad. Of the two adjacent lower shock absorber devices, the one closer to the lower extension end is the first lower shock absorber device, and the other is the second lower shock absorber device. The lower piston rod of the second lower shock absorber device extends into the lower cylinder chamber of the first lower shock absorber device and abuts against the lower elastic buffer device in the lower cylinder chamber of the first lower shock absorber device. The lower piston rod of the second lower shock absorber device is matched and connected to the lower cylinder chamber of the first lower shock absorber device.

5. The omnidirectional crash-resistant UAV with a series multi-level composite buffer structure as described in claim 3, characterized in that, Both the upper elastic damping device and the lower elastic damping device are damping springs; The central axes of the damping springs in the same composite upper or lower damping device are located on the same straight line. Both the upper and lower cylinder chambers have a limiting ring platform at the end of the cylindrical chamber away from the conical chamber to prevent the upper or lower piston rod from dislodging. The diameter of the upper or lower piston rod located in the upper or lower cylinder chamber near the limiting ring is not less than the inner diameter of the limiting ring.

6. The omnidirectional crash-resistant UAV with a series multi-level composite buffer structure as described in claim 1, characterized in that, The upper cylinder chamber and the upper piston rod extending into the upper cylinder chamber are in clearance fit; The depth of the cylindrical chamber of the upper cylinder is not greater than the maximum stroke of the upper elastic damping device when compressed. The lower cylinder chamber and the lower piston rod extending into the lower cylinder chamber are also clearance fit; The depth of the cylindrical chamber of the lower cylinder is not greater than the maximum stroke of the lower elastic damping device under compression.

7. The omnidirectional crash-resistant UAV with a series multi-level composite buffer structure as described in claim 1, characterized in that, The upper buffer cylinder is provided with an upper air inlet and an upper air outlet. The upper air inlet is provided with an upper air inlet one-way valve. Both the upper air inlet and the upper air outlet are connected to the upper cylinder chamber. An upper throttling vent valve is provided on the upper exhaust port.

8. The omnidirectional crash-resistant UAV with a series multi-level composite buffer structure as described in claim 3, characterized in that, The lower buffer cylinder is provided with a lower air inlet and a lower air outlet. The lower air inlet is provided with a lower air inlet one-way valve. Both the lower air inlet and the lower air outlet are connected to the lower cylinder chamber. A lower throttling vent valve is provided on the lower exhaust port.

9. The omnidirectional crash-resistant UAV with a series multi-level composite buffer structure as described in claim 3, characterized in that, A rubber cushioning airbag is fixedly connected to the ground mat. The rubber cushioning airbag is fixedly connected to one end of the ground mat via a mounting base and a lower piston rod. The rubber cushioning airbag is equipped with an inflation one-way valve.

10. An omnidirectional crashworthy unmanned aerial vehicle with a series multi-level composite buffer structure as described in claim 1, characterized in that, The cargo box has a double-layer impact-resistant structure, including an outer carbon fiber protective shell and an inner cushioning liner, with honeycomb cushioning material filling the space between the inner cushioning liner and the outer carbon fiber protective shell. The top of the cargo box is equipped with a docking plate, which is fixedly connected to the flight control platform through multiple matching quick-connect locking slots and quick-connect locks; The bottom of the cargo box is fixedly equipped with a bottom auxiliary cushioning pad; The cargo box is fixedly connected to the X-shaped mounting frame.

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