A parachute-free airdrop device capable of self-balancing crosswind-resistant ground contact load.

Abstract

This invention discloses a parachute-less airdrop device capable of achieving crosswind-resistant, ground-reaching, load-balanced self-balancing, specifically relating to the field of parachute-less airdrop technology. The device includes an airdrop body, an unlocking and buffering mechanism, a load self-balancing mechanism, and a pneumatic deceleration and attitude adjustment device. The airdrop body includes a housing with several through holes around its perimeter, triangular parallel threaded grooves above the through holes, and two limiting grooves. The two limiting grooves are located on milled planes within groups of four through holes. The unlocking and buffering mechanism includes several unlocking rings, several buffer legs, several unlocking springs, several unlocking blades, several spring connecting blocks, and several pairs of guide rails located on both sides of the buffer legs. This invention, through its vertical retention function after the effective load touches the ground, and the stable posture of the airdrop's outer packaging and the effective load inside the airdrop upon ground contact, provides convenience for transporting objects requiring vertical upward movement.

Description

Technical Field

[0001] This invention relates to the field of parachuteless airdrop technology, specifically to a parachuteless airdrop device capable of achieving self-balancing of crosswind-resistant ground-contact load. Background Technology

[0002] Research on parachuteless airdrop started earlier abroad, and its main direction is based on navigation guidance precision airdrop system[1] (Song Xumin, Cheng Wenke, Peng Yong, et al. Advanced precision airdrop system[J]. Aerospace Return and Remote Sensing, 2004, (01): 6-10.); [2] Zhang Feng, Wang Haitao. European and American precision airdrop system[J]. Ordnance Automation, 2007, (06): 103-104. The developed guidance precision airdrop system GPADS can meet the precision airdrop mission of different loads from 91 kg to 19,000 kg; [3] Wang, Yi, Chunxin Yang, and Han Yang. "Neural network-based simulation and prediction of precise airdrop trajectory planning." Aerospace Science and Technology 120(2022): 107302. Genetic algorithm (GA) and Kane equation (KE) were used to train, verify and test BPNN (a model for predicting a large amount of airdrop landing data), and the airdrop landing radius was reduced to 77% of the traditional GA method and 54.6% of the KE model; [4] Zhang, An, et al. "Adaptive mutant particle swarm optimizationbased precise cargo airdrop of unmanned aerial vehicles." Applied SoftComputing 130 (2022): 109657. An airdrop strategy (SW-CCRP) for fixed-wing UAVs to transport cargo to a designated location under strong wind conditions was proposed and its effectiveness was verified;

[0003] Research on parachuteless airdrop in China started relatively late. The main focus is on the design of ground-contact buffer structures, and many use fluid-filled buffer structures such as water bladders and air bladders to absorb energy. For example, [5] Zhou Yu, Li Jianyang, Xing Wei, et al. Research progress on key technologies of buffer air bladders for recovery [J]. Packaging Engineering, 2019, 40(1): 80-86. [6] Jia Shan, Gao Xiangyu, Chen Jinbao, et al. Packaging design for low-altitude parachute-free and damage-free airdrop and verification of its self-stabilization and buffering performance [J]. Aerospace Return and Remote Sensing, 2022, 43(02):1-44. The attitude of the airdrop during the descent is stabilized by a self-deploying flexible wind resistance structure, and the landing accuracy of the airdrop at a height of 50m is controlled within 0.1m; [7] Ma Xiaoguang, Huo Ruikun, Han Minggang, et al. Finite element method strength optimization of airdrop leg buffer device [J]. Value Engineering, 2019, 38(29):165-168. In view of the problem of lightweighting of leg buffer, four variables, namely piston rod diameter, piston diameter, piston thickness and cylinder thickness, are optimized to obtain the minimum design size; [8] Zhu Jingshan, Xi Zhaojun, Wu Zhongda, et al. Water bladder assembly Airdrop impact simulation and optimization design [J]. Packaging Engineering, 2023, 44(07): 307-313. A water bladder assembly was designed and its reliability was verified by simulation; [9] Zhang Yuting, Geng Xiaokai, Ren Chunhua, et al. High-altitude drop simulation analysis of umbrella-less airdrop storage tank [J]. Packaging Engineering, 2022, 43(01): 66-74. Increasing the thickness of the storage tank and using a foam layer to reduce the counterweight reduces the overall weight while ensuring the performance of the airdrop;

[10] Shi Yongsheng, Sun Wenze. Influence of fiber hybrid layup on the impact resistance of umbrella-less airdrop box [J]. Packaging Engineering, 2023, 44(01): 300-308. Fiber hybrid layup was used to buffer the umbrella-less airdrop, and the composite layup suitable for buffering was obtained by comparison.

[0004] Current simulations of parachuteless airdrops primarily focus on the touchdown phase, neglecting the impact of aerodynamics on the airdrop's landing speed and attitude. Airbag-shaped airdrops require a relatively steep ground slope; on sloping terrain, the deviation between the stabilized position and the drop point becomes unpredictable. Leg-type and layered cushioning systems generally have a normal operating attitude range; exceeding this range can lead to partial touchdowns, causing localized packaging damage or even core load failure. Therefore, ensuring the airdrop's attitude upon touchdown is crucial. Existing airdrops rarely possess a function to maintain the vertical position of the core load after touchdown. The stable attitude of the outer packaging and the core load upon touchdown pose significant challenges for transporting items requiring vertical alignment. Summary of the Invention

[0005] To address the shortcomings of existing parachute-less airdrop packaging in terms of attitude maintenance, post-contact anchoring, and post-contact load self-balancing, this invention provides a parachute-less airdrop device capable of achieving crosswind-resistant ground contact load self-balancing. This device combines a strip wind-shelter structure with buffer legs and optimizes them to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact buffer load, the device comprising an airdrop body, an unlocking buffer mechanism, a load self-balancing mechanism, and a pneumatic deceleration and attitude adjustment device.

[0007] The airdrop body includes a box, which includes several through holes around its perimeter, a triangular parallel threaded groove located above the through holes, and two limiting grooves; the two limiting grooves are respectively located on the milled plane in a group of four through holes.

[0008] The unlocking buffer mechanism includes several unlocking rings, several buffer legs, several unlocking springs, several unlocking blades, several spring connecting blocks, and several pairs of guide rails arranged on both sides of the buffer legs.

[0009] The unlocking ring includes a second triangular parallel threaded groove on the inner wall of the top of the unlocking ring and a connecting hole on the outer wall of the top of the unlocking ring; the second triangular parallel threaded groove is connected to the first triangular parallel threaded groove on the housing.

[0010] The non-ground-contact end of the buffer leg has a through hole, and the through hole is connected to the slider by a screw and nut. The slider has a groove.

[0011] The unlocking spring includes two through holes.

[0012] The unlocking knife has an unlocking handle glued to a groove in the buffer leg; the unlocking knife is located below the unlocking spring, which is initially in a ring-shaped and stretched state, and after the unlocking knife cuts the unlocking spring, the unlocking spring tends to remain vertical;

[0013] The several through holes three on the spring connecting block are connected to the corresponding through holes two on the unlocking spring by screws and nuts and are glued to the unlocking ring;

[0014] The guide rail includes several through holes and a groove. The several through holes are connected to several through holes on the housing by screws and nuts. The slider slides along the direction of the groove.

[0015] The load self-balancing mechanism includes an outer ring, an inner ring hinged to the outer ring, and an effective load fixedly connected to the inner ring.

[0016] The outer ring includes a pair of outer ring hinge joints and two outer ring hinge interfaces; the outer ring hinge joints mate with the limiting grooves on the housing; the inner ring includes a pair of first inner ring hinge joints and several second inner ring hinge joints, the pair of first inner ring hinge joints mate with the outer ring hinge interfaces of the outer ring; the effective load includes several effective load hinge interfaces, the several effective load hinge interfaces are fixedly connected to four second inner ring hinge joints on the inner ring;

[0017] Preferably, the airdrop body also includes a top cover located above the container, the bottom end of which has a connection point and is connected to the container by an interference fit.

[0018] Preferably, the unlocking buffer mechanism further includes several pads, each pad having several through holes. The pads are located between the buffer leg and the housing, and are mainly used to cushion the impact of the buffer leg on the housing. They also have a certain function of maintaining the sliding direction of the buffer leg within the guide rail. The through holes are connected to the through holes of the buffer leg by bolts and are located in the groove of the guide rail.

[0019] Preferably, the pneumatic deceleration and attitude adjustment device includes a connecting ring, several connecting rods, a striped windshield frame, and a striped windshield fabric;

[0020] The connecting ring includes several through holes and several square holes; the connecting rod connects the through holes of the connecting ring and the connecting hole of the unlocking ring through an overfit; the strip windproof frame includes an upper frame, a lower frame and a sub-frame, which are respectively fixed in several square holes on the connecting ring through an overfit adhesive, and the strip windproof fabric is fixed to the strip windproof frame through adhesive.

[0021] The present invention has the following advantages:

[0022] This invention achieves the ground-touching buffer characteristic by unlocking the buffer mechanism and the load self-balancing mechanism. When the airdropped body touches the ground, the buffer legs come into contact with the ground. The structure around the bottom of the legs has poor strength and begins to deform and absorb energy, thereby achieving the ground-touching buffer characteristic.

[0023] After the airdrop body 1 lands, the buffer leg 202 absorbs energy and deforms, and the airdrop body 1 quickly stabilizes. The outer ring 301 slides out of the limiting groove 10103 of the box 101, gaining the degree of freedom to rotate vertically in the two limiting grooves. The hinge between the outer ring 301 and the inner ring 302 gives the degree of freedom perpendicular to the rotation direction of the outer ring 301 and the direction of the main axis of the box 101. The fixed connection between the inner ring 302 and the effective load 303 gives the load self-balancing mechanism 3 two rotational degrees of freedom θx and θz. Therefore, when the center of gravity O of the payload 303 is not directly below the intersection point O1, a restoring torque M will be generated to make the center of gravity O vertical with the intersection point O1. Thus, the center of gravity O always tends to be directly below the intersection point O1 of the two rotation axes, thereby achieving the "load self-balancing" characteristic. Compared with the existing technology, the vertical holding function of the payload after touching the ground, the stable posture of the airdropped outer packaging after touching the ground, and the posture of the airdropped payload are convenient for transporting some objects that require vertical upward movement. Attached Figure Description

[0024] Figure 1 This is a grouping diagram of the overall components of a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact load according to an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the airdrop body in an airdrop device that can achieve self-balancing of crosswind-resistant ground contact buffer load according to an embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of the box in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact load according to an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the top cover of a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact load according to an embodiment of the present invention.

[0028] Figure 5 This is a schematic diagram of the unlocking buffer mechanism in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact buffer load according to an embodiment of the present invention.

[0029] Figure 6 This is a schematic diagram of the unlocking ring in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground-contact buffer load according to an embodiment of the present invention.

[0030] Figure 7 This is a schematic diagram of the buffer leg in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact load according to an embodiment of the present invention.

[0031] Figure 8This is a schematic diagram of the unlocking spring in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact load according to an embodiment of the present invention.

[0032] Figure 9 This is a schematic diagram of the unlocking blade in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact buffer load according to an embodiment of the present invention;

[0033] Figure 10 This is a schematic diagram of a spring connecting block in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact load according to an embodiment of the present invention.

[0034] Figure 11 This is a schematic diagram of the guide rail in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact load according to an embodiment of the present invention.

[0035] Figure 12 This is a schematic diagram of a pad block in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact load according to an embodiment of the present invention.

[0036] Figure 13 This is a schematic diagram of a load self-balancing mechanism in a parachute-less airdrop device that can achieve self-balancing of crosswind-resistant ground-contact buffer load according to an embodiment of the present invention;

[0037] Figure 14 This is a schematic diagram of the outer ring in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact buffer load according to an embodiment of the present invention.

[0038] Figure 15 This is a schematic diagram of the inner ring of a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground-contact load according to an embodiment of the present invention.

[0039] Figure 16 This is a schematic diagram of the effective load in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact buffer load according to an embodiment of the present invention.

[0040] Figure 17 This is a schematic diagram of the aerodynamic deceleration and attitude adjustment device in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact buffer load according to an embodiment of the present invention.

[0041] Figure 18 This is a schematic diagram of the connecting ring in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground-contact load according to an embodiment of the present invention;

[0042] Figure 19 This is a schematic diagram of a connecting rod in a parachute-free airdrop device that can achieve self-balancing of crosswind-resistant ground contact load according to an embodiment of the present invention.

[0043] Figure 20This is a schematic diagram of the strip wind shield frame in a parachute-free airdrop device that can achieve self-balancing of crosswind ground contact buffer load according to an embodiment of the present invention;

[0044] Figure 21 This is a schematic diagram of the striped windproof tarpaulin in an umbrella-less airdrop device that can achieve self-balancing of crosswind ground contact buffer load according to an embodiment of the present invention;

[0045] Figure 22 This is a schematic diagram of the deceleration and attitude adjustment principle provided by the present invention;

[0046] Figure 23 A schematic diagram of the self-balancing principle provided by the present invention;

[0047] Figure 24 The comparison diagram before and after optimization provided by this invention;

[0048] Figure 25 The optimization process flowchart provided by this invention;

[0049] Figure 26 A schematic diagram of the design parameters of the parachute-free airdrop device provided by the present invention;

[0050] Figure 27 The target variable and design variable cloud diagram provided for this invention;

[0051] Figure 28 A graph showing the changes in falling speed and falling attitude data for the initial scheme provided by this invention;

[0052] Figure 29 A comparison diagram of the speed and attitude of the optimized configuration and the follower configuration provided by this invention.

[0053] In the diagram: 1. Airdrop body; 101. Box body; 10101. Through hole; 10102. Parallel threaded groove one; 10103. Limiting groove; 102. Top cover; 10201. Connection point; 2. Unlocking buffer mechanism; 201. Unlocking ring; 20101. Parallel threaded groove two; 20102. Connection hole; 202. Buffer leg; 20201. Slider; 20202. Through hole one; 20203. Groove; 203. Unlocking spring; 20301. Through hole two; 204. Unlocking knife; 20401. Unlocking knife handle; 205. Spring connecting block; 20501. Through hole three; 206. Guide rail; 20601. Through hole 4. 207. Pad; 20701. Through Hole 5; 3. Load self-balancing mechanism; 301. Outer ring; 30101. Outer ring hinge joint; 30102. Outer ring hinge interface; 302. Inner ring; 30201. First inner ring hinge joint; 30202. Second inner ring hinge joint; 303. Payload; 30301. Payload hinge interface; 4. Pneumatic deceleration and attitude adjustment device; 401. Connecting ring; 40101. Through Hole 6; 40102. Square hole; 402. Connecting rod; 403. Striped windproof frame; 40301. Upper frame; 40302. Lower frame; 40303. Sub-frame; 404. Striped windproof fabric. Detailed Implementation

[0054] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] like Figures 1-22 As shown, this embodiment provides a parachute-free airdrop device that can achieve crosswind-resistant ground contact buffer load self-balancing. The device includes an airdrop body 1, an unlocking buffer mechanism 2, a load self-balancing mechanism 3, and a pneumatic deceleration and attitude adjustment device 4.

[0056] The airdrop body 1 includes a box 101, which includes a plurality of through holes 10101 around its perimeter, a triangular parallel threaded groove 10102 located above the plurality of through holes 10101, and two limiting grooves 10103; the two limiting grooves 10103 are respectively located on the milled plane in the four through holes 10101 in a group;

[0057] The unlocking buffer mechanism 2 includes several unlocking rings 201, several buffer legs 202, several unlocking springs 203, several unlocking blades 204, several spring connecting blocks 205, and several pairs of guide rails 206 disposed on both sides of the buffer legs 202.

[0058] The unlocking ring 201 includes a second triangular parallel threaded groove 20101 on the inner wall of the top of the unlocking ring 201 and a connecting hole 20102 on the outer wall of the top of the unlocking ring 201; the second triangular parallel threaded groove 20101 and the first triangular parallel threaded groove 10102 on the housing 101 cooperate to connect, so as to facilitate the unlocking ring 201 and the housing 101 to unlock.

[0059] The non-ground-contact end of the buffer leg 202 is provided with a through hole 20202, and the through hole 20202 is connected to the slider 20201 by screws and nuts. The slider 20201 is provided with a groove 20203.

[0060] The unlocking spring 203 includes two through holes 20301;

[0061] The unlocking knife 204 has an unlocking handle 20401 glued to the groove 20203 of the buffer leg 202; the unlocking knife 204 is located below the unlocking spring 203, the unlocking spring 203 is initially in a ring and in a stretched state, and after the unlocking knife 204 cuts the unlocking spring 203, the unlocking spring 203 tends to remain vertical.

[0062] The several through holes 20501 on the spring connecting block 205 are connected to the through holes 20301 on the corresponding unlocking spring 203 by screws and nuts and are glued to the unlocking ring 201.

[0063] The guide rail 206 includes several through holes 20601 and grooves 20602. The several through holes 20601 are connected to several through holes 10101 on the housing 101 by screws and nuts. The slider 20201 slides along the direction of the groove 20602.

[0064] The load self-balancing mechanism 3 includes an outer ring 301, an inner ring 302 hinged to the outer ring 301, and an effective load 303 fixedly connected to the inner ring 302.

[0065] The outer ring 301 includes a pair of outer ring hinge joints 30101 and two outer ring hinge interfaces 30102; the outer ring hinge joints 30101 cooperate with the limiting grooves 10103 on the housing 101; the inner ring 302 includes a pair of first inner ring hinge joints 30201 and several second inner ring hinge joints 30202, the pair of first inner ring hinge joints 30201 cooperate with the outer ring hinge interfaces 30102 of the outer ring 301; the effective load 303 includes several effective load hinge interfaces 30301, the several effective load hinge interfaces 30301 are fixedly connected to four second inner ring hinge joints 30202 on the inner ring 302;

[0066] Preferably, the airdrop body 1 further includes a top cover 102 located above the box body 101, the bottom end of the top cover 102 having a connection 10201 and the connection 10201 being connected to the box body 101 by an interference fit.

[0067] Preferably, the unlocking buffer mechanism 2 further includes several pads 207, each pad 207 having several through holes 20701. The pads 207 are located between the buffer leg 202 and the housing 101, and are mainly used to cushion the impact of the buffer leg 202 on the housing 101. They also have a certain function of maintaining the sliding direction of the buffer leg 202 within the guide rail 206. The through holes 20701 are bolted to the through holes 20202 of the buffer leg 202 and are located in the grooves 20602 of the guide rail 206.

[0068] Preferably, the pneumatic deceleration and attitude adjustment device 4 includes a connecting ring 401, a plurality of connecting rods 402, a striped windproof frame 403, and a striped windproof fabric 404;

[0069] The connecting ring 401 includes several through holes 40101 and several square holes 40102; the connecting rod 402 connects the through holes 40101 of the connecting ring 401 with the connecting hole 20102 of the unlocking ring 201 through an overfit; the striped windproof frame 403 includes an upper frame 40301, a lower frame 40302 and a sub-frame 40303, which are respectively fixed in the several square holes 40102 on the connecting ring 401 through an overfit adhesive, and the striped windproof fabric 404 is fixed to the striped windproof frame 403 through adhesive.

[0070] The use of striped windproof fabric 404 reduces the lateral windward area compared to traditional parachutes, thus reducing the torque of crosswinds on the airdropped body 1 and mitigating the effect of crosswinds.

[0071] This embodiment provides a parachute-less airdrop device capable of self-balancing crosswind-resistant ground contact load buffering, which includes the following processes during operation:

[0072] 1. In-flight deceleration and attitude adjustment process

[0073] After the airdrop body 1 is deployed, it moves downwards under the influence of gravity. A force diagram of the parachute-less airdrop during its descent is drawn, as follows: Figure 23 As shown. The height of the parachute-less airdrop is L, and the gravity is G. Since the main mass is concentrated in the effective payload 303, its center of mass is located at a = 0.1m below the upper surface of the device. When the airdrop is in free fall in the air after being airdropped, due to the influence of machining accuracy, asymmetry of air resistance, and crosswinds, the forces on both sides of the device's central axis will not be the same. Therefore, the attitude angle of the airdrop caused by various reasons is denoted as θ.

[0074] In this situation, due to the obstruction effect of the airdrop, the windward side of the airdrop body 1 and the hood 404 will experience greater wind resistance than the leeward side. Simultaneously, because the upper part has a larger deployment angle, its windward area S is larger than that of the lower part, according to the air resistance calculation formula... In the formula, This is the drag coefficient. air density, To ensure effective windward area, Due to the airdrop's descent speed, the upper layer of the double-layered striped windproof cover 404 will bear more aerodynamic drag than the lower layer. Therefore, the aerodynamic drag on the airdrop body 1 and the aerodynamic drag on the striped windproof cover 404 will form a resultant force. Since the airdrop's descent speed is greater than (up to 10 times) the crosswind speed, the aerodynamic drag can be considered as an upward vertical force. When the attitude deviates, the resultant force of the wind resistance on the windward side is reasonably greater than that on the leeward side. Therefore, this difference in aerodynamic drag will generate a torque M that corrects the airdrop's orientation, thus achieving the characteristic of deceleration and attitude adjustment.

[0075] 1.1 Orthogonal Optimization Design

[0076] 1.11 Optimization Methods

[0077] The umbrella-less wind shield structure and energy-absorbing legs provide an effective buffer and energy absorption method for umbrella-less airdrops. However, the simulation process involves too much computation and takes too long, with a single operation taking up to 8 hours. Therefore, it cannot be optimized using optimization algorithms that require a large number of data samples.

[0078] Therefore, this paper employs orthogonal experimental design to reasonably select a set of design variables within the feasible region of the design variables of the airdrop model, ensuring that this set fully reflects the relationship between the optimization objective variables and the design variables. Using finite element parametric simulation, parametric simulation calculations are performed on the selected sample models to obtain the optimization objective variable values ​​corresponding to each sample model in the solution set. The response surface methodology is used to analyze the data obtained from the finite element analysis, fitting the optimization objective and selecting the optimal solution or solution set. Finally, a configuration is selected within the design variable range, and its objective parameters are compared with the optimal solution set to verify the correctness of the optimal solution set. The optimization process flowchart is as follows: Figure 25 As shown.

[0079] 1.12 Design Variables and Objective Function

[0080] To ensure the self-correcting function of the double-layer flexible structure remains unaffected, two parameters for parachute-free airdrop are selected as design variables: l—length of the wind-resistant material; h—height of the wind-resistant material, such as... Figure 26 As shown.

[0081] Where 'l' represents a multiple relationship, the initial model's windshield length is denoted as 'l0', and subsequent optimized model lengths are denoted as 1.3l0, 1.5l0, and so on. As the windshield size 'l' increases, its vertical projected area and windward area increase, thus increasing wind resistance during descent. Due to uncertainties in manufacturing precision and the magnitude and direction of crosswind speed during descent, the potential difference in wind resistance between the two sides of the airdrop also increases as the windshield size 'l' increases. Therefore, the final landing speed is expected to decrease as the windshield length 'l' increases, and the air attitude angle will become more unstable. 'h' represents the height of the windshield from the airdrop body; the initial model has h=0. As the windshield height 'h' increases, the gap between the windshield and the airdrop widens, allowing air to flow more easily between them to generate greater lift. However, as the windshield height 'h' increases, the aerodynamic point of action, i.e., the focal point, shifts upwards, and the center of mass also shifts upwards, making the attitude angle difficult to estimate. Therefore, the final landing speed is expected to decrease as the wind speed h increases. The relationship between the aerial attitude angle and the wind speed h is not yet clear and needs to be analyzed through simulation and experimentation.

[0082] There are two main indicators for evaluating airdrop performance: ground contact velocity and maximum attitude angle. The airdrop ground contact buffering process is the process of absorbing and converting all kinetic energy, according to the kinetic energy formula... The velocity of the airdrop upon impact has a significant impact on the airdrop cushioning process. Airdrop cushioning is directional, and most impact cushioning devices require a specific impact posture to be effective. Therefore, the maximum attitude angle is a key factor in evaluating airdrop success. Thus, the impact velocity and maximum attitude angle are used as objective functions.

[0083] For the optimization of the deceleration and buffer device for parachuteless airdrop and the multi-objective reverse-flow, the airdrop ground contact speed and maximum attitude angle are taken as optimization objectives, and the parachute length and height are taken as design variables. The optimization mathematical model is as follows:

[0084]

[0085] In the formula: This refers to the airdrop's contact speed with the ground. l0 represents the maximum attitude angle for airdrop; l0 represents the initial parachute length.

[0086] 1.13 The range of values ​​for design variables and the values ​​for orthogonal experiments

[0087] Orthogonal experimental design should consider how to arrange multi-factor, multi-level experiments to obtain the required analytical data reasonably and effectively, and use appropriate methods to analyze these data to determine which factors are the main factors and what combination of levels of each factor is optimal for the experimental indicators.

[0088] Based on engineering experience, the value ranges of two design variables were selected, and the values ​​of the design variables should conform to the actual engineering situation. Therefore, 25 different samples were selected based on the combination of the two design variables, and the first 10 samples were shown in Table 1.

[0089] Table 1 Range of Design Variable Values

[0090]

[0091] 1.14 Response surface methodology was used for analysis.

[0092] Table 2 Experimental Results

[0093]

[0094] Based on the data in Table 2, a quadratic polynomial regression model of the velocity and maximum attitude angle during the parachute-less airdrop descent process was obtained using Design-Expert software:

[0095] Table 3. Variance Analysis of the Supplementary Quadratic Polynomial Model for Ground Contact Velocity of Parachute-less Airdrops

[0096]

[0097] Table 4. Variance Analysis of the Supplementary Quadratic Polynomial Model for Maximum Attitude Angle in Parachute-less Airdrop

[0098]

[0099] Analysis of variance (ANOVA) on the quadratic polynomial regression equations (Tables 3 and 4) shows that the F-value of the regression equation model for the descent velocity after supplementing the data is 76.73, and the p-value is <0.0001, therefore this model is considered significant. In this model, the p-values ​​of A, B, AB, and A2B are <0.05, therefore they are considered to have a significant impact on the descent velocity. The regression equation model for the maximum attitude angle after supplementing the data has an F-value of 31.93, and the p-value is 0.0002 <0.05, therefore this model is considered significant. In this model, the p-values ​​of A², B², A²B, AB², A², B², A²B, AB², A²B², A²B², AB², A², A²B², A²B, and A6 are <0.05, therefore they are considered to have a significant impact on the maximum attitude angle.

[0100] Table 5. Velocity model fitting data

[0101]

[0102] Table 6. Attitude Model Fitting Data

[0103]

[0104] The regression equation for velocity has a multivariate correlation coefficient R² = 0.9693, CV = 2.24% < 10%, and AdeqPrecisior = 28.9061 > 4. Therefore, the experiment can be considered to have high reliability and accuracy, and the fitted regression equation has high reliability. The regression equation for the maximum attitude angle has a multivariate correlation coefficient R² = 0.9897, CV = 6.11% < 10%, and AdeqPrecisior = 26.7092 > 4. Therefore, the experiment can be considered to have high reliability and accuracy, and the fitted regression equation has high reliability.

[0105] Based on the quadratic polynomial regression model of the descent speed and maximum attitude angle obtained above for parachute-less airdrop, a cloud map of the target variable and design variable can be plotted. The cloud map shows that for descent speed, a longer parachute and higher parachute height result in a slower ground contact speed. For the maximum attitude angle, the configurations shown in red in the diagram, namely 1.05l0, 1.45l0, and 1.75l0, should be avoided. Overlaying the two cloud maps yields the optimal configuration solution set within a given range (l0~1.8l0, h0~h150). The selected optimal configuration solution set includes 1.3l0h150, 1.65l0h125, 1.8l0h0, 1.8l0h50, 1.8l0h100, 1.8l0h150, and solutions within their surrounding regions.

[0106] Simulations show that without a wind-assisted landing gear, the ground contact velocity is 15 m / s, making it difficult to maintain the airborne attitude (resulting in somersaults). The wind-assisted landing gear can reduce the ground contact velocity to 9 m / s, while maintaining the airborne attitude within 20°. Figure 24 As shown.

[0107] Figure 28 The data for the initial descent velocity and attitude are shown, with a maximum velocity of 12.4 m / s and a maximum attitude angle of 21.6°.

[0108] Figure 29 The speed and attitude of the optimized configuration and the random configuration are compared (the top three black-red-green configurations are the optimized configurations). The optimized configuration can reach a ground contact speed of 9.05 m / s and a maximum attitude angle of 19°.

[0109] 2. Ground contact buffering process

[0110] After the airdropped main body 1 touches the ground, the cushioning legs 202 come into contact with the ground. The structure around the bottom of the legs is relatively weak, so it begins to deform and absorb energy, thereby achieving the characteristic of ground impact cushioning.

[0111] 3. Unlocking process

[0112] After the airdropped body 1 touches the ground, the buffer leg 202 contacts the ground. Due to the slider 20201 on the buffer leg 202 and the groove 20601 on the guide rail 206, the buffer leg 202 moves upward relative to the guide rail 206. The buffer leg 202 drives the unlocking knife 204 to cut the unlocking spring 203. The unlocking spring 203, made of elastic thin metal, drives the unlocking ring 201 to spring open, and the unlocking is completed, thus achieving the characteristic of unlocking upon contact with the ground.

[0113] 4. Load self-balancing process

[0114] like Figure 24 As shown, after the airdrop body 1 lands, the buffer leg 202 absorbs energy and deforms, and the airdrop body 1 quickly stabilizes. The outer ring 301 slides out of the limiting groove 10103 of the box 101, gaining the degree of freedom to rotate vertically in the two limiting grooves. The hinge between the outer ring 301 and the inner ring 302 provides a degree of freedom perpendicular to the rotation direction of the outer ring 301 and the main axis of the box 101. The fixed connection between the inner ring 302 and the effective load 303 gives the load self-balancing mechanism 3 two rotational degrees of freedom, θx and θz. Therefore, when the center of gravity O of the effective load 303 is not directly below the intersection point O1, a restoring torque M will be generated to make the center of gravity O and the intersection point O1 vertical. Thus, the center of gravity O always tends to be directly below the intersection point O1 of the two rotation axes, thereby achieving the "load self-balancing" characteristic.

[0115] When there is a crosswind, it does not act directly on the payload 303, which has most of the mass, but rather on the aerodynamic deceleration and attitude adjustment device 4. Since the rotational degree of freedom axis of the load self-balancing device 3 is closer to the center of mass, the attitude of the payload 303 is less affected by the crosswind. The aerodynamic deceleration and attitude adjustment device 4 is lighter in mass and more susceptible to the direction of the wind, but the main wind speed when it touches the ground comes from the vertical direction, so the crosswind will not have a significant impact on the aerodynamic deceleration and attitude adjustment device 4.

[0116] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A parachute-free aerial delivery device capable of self-balancing against crosswind touchdown cushion loads, characterized by: The device includes an airdrop body (1), an unlocking buffer mechanism (2), a load self-balancing mechanism (3), and a pneumatic deceleration and attitude adjustment device (4). The airdrop body (1) includes a box (101), the box (101) includes a through hole (10101) provided around its body, a triangular parallel threaded groove (10102) located above the through hole (10101) and a limiting groove (10103); the two limiting grooves (10103) are respectively located on the milled plane in the four through holes (10101) in a group; The unlocking buffer mechanism (2) includes an unlocking ring (201), a buffer leg (202), an unlocking spring (203), an unlocking blade (204), a spring connecting block (205), and guide rails (206) disposed on both sides of the buffer leg (202). The unlocking ring (201) includes a second triangular parallel threaded groove (20101) on the inner wall of the top of the unlocking ring (201) and a connecting hole (20102) on the outer wall of the top of the unlocking ring (201); the second triangular parallel threaded groove (20101) is connected to the first triangular parallel threaded groove (10102) on the housing (101); The buffer leg (202) has a through hole (20202) on its non-grounding end. The through hole (20202) is connected to the slider (20201) by a screw and nut. The slider (20201) has a groove (20203). The unlocking spring (203) includes two through holes (20301). The unlocking knife (204) has an unlocking handle (20401) glued to the groove (20203) of the buffer leg (202); the unlocking knife (204) is located below the unlocking spring (203), the unlocking spring (203) is initially in a ring and in a stretched state, and after the unlocking knife (204) cuts the unlocking spring (203), the unlocking spring (203) tends to remain vertical; The several through holes three (20501) on the spring connecting block (205) are connected to the corresponding through holes two (20301) on the unlocking spring (203) by screws and glued to the unlocking ring (201); The guide rail (206) includes a through hole (20601) and a groove (20602). The through hole (20601) is connected to the through hole (10101) on the housing (101) by screws and nuts. The slider (20201) slides along the direction of the groove (20602). The load self-balancing mechanism (3) includes an outer ring (301), an inner ring (302) hinged to the outer ring (301), and an effective load (303) fixedly connected to the inner ring (302). The outer ring (301) includes an outer ring hinge joint (30101) and an outer ring hinge interface (30102); the outer ring hinge joint (30101) cooperates with the limiting groove (10103) on the housing (101); the inner ring (302) includes a first inner ring hinge joint (30201) and a second inner ring hinge joint (30202), the first inner ring hinge joint (30201) cooperates with the outer ring hinge interface (30102) of the outer ring (301); the payload (303) includes a payload hinge interface (30301), the payload hinge interface (30301) is fixedly connected to the second inner ring hinge joint (30202) on the inner ring (302).

2. The parachute-less airdrop device according to claim 1, which can achieve self-balancing of crosswind-resistant ground contact load, is characterized in that: The airdrop body (1) also includes a top cover (102) located above the box (101), the bottom end of the top cover (102) having a connection (10201) and the connection (10201) being connected to the box (101) by an interference fit.

3. The parachute-less airdrop device according to claim 1, which can achieve self-balancing of crosswind-resistant ground contact load, is characterized in that: The unlocking buffer mechanism (2) also includes a pad (207), on which a through hole five (20701) is provided. The through hole five (20701) is connected to the through hole one (20202) of the buffer leg (202) by bolts and is located in the groove (20602) of the guide rail (206).

4. The parachute-less airdrop device according to claim 1, which can achieve self-balancing of crosswind-resistant ground contact load, is characterized in that: The pneumatic deceleration and attitude adjustment device (4) includes a connecting ring (401), a connecting rod (402), a striped windproof frame (403), and a striped windproof cloth (404). The connecting ring (401) includes a through hole six (40101) and a square hole (40102); the connecting rod (402) is connected to the connecting hole six (40101) of the connecting ring (401) and the connecting hole (20102) of the unlocking ring (201) by an overfit; the striped windproof frame (403) includes an upper frame (40301), a lower frame (40302) and a sub-frame (40303), which are respectively fixed in the square hole (40102) on the connecting ring (401) by an overfit adhesive, and the striped windproof cloth (404) is fixed to the striped windproof frame (403) by adhesive.

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