阅读说明：本技术 一种基于薄翼理论设计的变桨距折叠旋翼伞降空投装置 (Variable-pitch folding rotor parachute drop air-drop device based on thin-wing theoretical design ) 是由 郭庆 薛文灏 顾佳辉 于 2021-09-08 设计创作，主要内容包括：本发明公开了一种基于薄翼理论设计的变桨距折叠旋翼伞降空投装置,涉及空投技术领域,包括货舱、翼头和折叠旋翼三部分；所述货舱整体形状为六面体结构,所述货舱包括底座,所述底座的六个角上均设有连接杆,相邻两个所述连接杆之间设有舱壁,所述连接杆的上端设有顶板,所述顶板的外侧设有六个连接架,所述顶板中心通过连接轴和连接架连接在货舱上部；本发明在原传统伞降空投的基础上,增加了可折叠的旋翼设备,并通过数学建模和参数优化得出了旋翼的安装角和半展长耦合下的最优参数选择。与传统伞降空投相比,带有自旋翼的空投设备具有高升阻比、桨距可调、低故障率、低成本、受气候影响小等优势,且对物资的降落速度和位置能进一步跟踪。(The invention discloses a variable-pitch folding rotor wing parachuting air-drop device designed based on a thin wing theory, which relates to the technical field of air-drop and comprises a cargo hold, a wing head and a folding rotor wing; the whole cargo compartment is of a hexahedral structure and comprises a base, connecting rods are arranged at six corners of the base, a compartment wall is arranged between every two adjacent connecting rods, a top plate is arranged at the upper end of each connecting rod, six connecting frames are arranged on the outer side of each top plate, and the center of each top plate is connected to the upper part of the cargo compartment through a connecting shaft and the connecting frames; on the basis of the original traditional parachute drop air drop, the foldable rotor wing equipment is added, and the optimal parameter selection under the coupling of the installation angle and the half span length of the rotor wing is obtained through mathematical modeling and parameter optimization. Compared with the traditional parachute drop air drop, the air drop device with the self-rotary wing has the advantages of high lift-drag ratio, adjustable propeller pitch, low failure rate, low cost, small influence of weather and the like, and can further track the dropping speed and position of materials.)

1. The utility model provides a folding rotor parachute drop device of feather based on thin wing theoretical design which characterized in that: comprises three parts of a cargo hold, a wing head and a folding rotor wing;

the whole cargo compartment is of a hexahedral structure, the cargo compartment comprises a base (1), connecting rods (2) are arranged at six corners of the base (1), a compartment wall (3) is arranged between every two adjacent connecting rods (2), a top plate (4) is arranged at the upper end of each connecting rod (2), six connecting frames (5) are arranged on the outer side of each top plate (4), and the center of each top plate (4) is connected to the upper part of the cargo compartment through a connecting shaft (6) and the connecting frames (5); the wing head comprises a wing head box body (8), steering engine mounting plates (10) in three directions are arranged inside the wing head box body (8), a bearing seat (7) is arranged in the middle of the inside of the wing head box body (8), and the bearing seat (7) is assembled and connected with a connecting shaft (6);

a support plate (9) is arranged on the outer side of the bearing seat (7);

the folding rotor wing comprises a wing root (11) and an outer wing (13), and the wing root (11) section is connected with the outer wing (13) section through a carbon tube; the side surface of the wing root (11) is connected with a mounting shaft (12), and the other end of the mounting shaft (12) is connected with a rudder angle in the wing head and a steering engine; the wing root (11) and the outer wing (13) are connected through a stainless steel 304 hinge with a torsion spring.

2. A pitching folding rotor parachute device designed based on the thin wing theory according to claim 1, characterized in that the bulkhead (3), the base (1), the top plate (4) and the connecting frame (5) are provided with corresponding lightening holes considering the material strength.

3. A variable-pitch folding rotor parachute device designed based on the thin wing theory as claimed in claim 2, wherein both ends of the mounting plate (10) are fixedly connected to the inner wall of the wing head box body (8), the surface of the mounting plate (10) is provided with a group of large round holes, a group of rectangular openings and a group of mounting holes, the large round holes are used for wiring inside the wing head, and the mounting holes are used for mounting the folding rotor.

4. A device for the airborne delivery of a folded-rotor pitch parachute based on the design of the thin wing theory according to claim 3, wherein the base (1) and the top plate (4) are both made of carbon fiber material.

5. A device for the airborne delivery of a folded-rotor pitch parachute based on the thin-wing theoretical design according to claim 4, wherein the bulkhead (3) is made of acrylic material.

6. A device for the parachuting of a folded rotor with variable pitch designed on the basis of the theory of thin wings according to claim 5, characterized in that the angle of installation of the outer wing (13) is 8 ° -12 °.

7. A device for the parachuting of a folded rotor with variable pitch designed on the basis of the theory of thin wings according to claim 6, characterized in that the half span length of the outer wing (13) is 0.35m to 0.5 m.

8. A pitch-controlled folding rotor parachute arrangement designed on the basis of the thin-wing theory according to any one of claims 1 to 7, wherein the lower ends of six connecting rods (2) of the cargo compartment extend downward through the base (1), and the lower ends of the connecting rods (2) are provided with shock-absorbing and cushioning members.

9. The variable-pitch folding rotor parachute device designed based on the thin-wing theory as claimed in claim 8, wherein night-time visible lights are arranged on the outer side wall of the cargo compartment.

Technical Field

The invention belongs to the technical field of technical airdrop, and particularly relates to a variable-pitch folding rotor parachute drop device designed based on a thin wing theory.

Background

In the air-drop mode, the traditional parachute always occupies the mainstream position. The parachute is invented by the inventor, and has a plurality of advantages through continuous improvement of the process and gradual optimization of the design. However, the mode of 'canopy + parachute line' is adopted, so that the speed is reduced mainly by the aid of differential pressure resistance when the parachute falls, the potential is nearly the limit, and some outstanding problems cannot be solved effectively all the time. For example, the cost and the loss of the parachute are always quite high whether the supplies are supplied during war or the supplies are delivered for emergency rescue, and the secondary loss caused by failure and large dispersion degree due to the influence of climate and environment can exist; in addition, the goods and materials are in an irrespective state after being thrown after the parachute is descended, the falling speed and the falling position of the thrown goods and materials cannot be monitored and fed back in real time, and the parachute is very complicated to recover and fold. Compared with the prior art, the self-rotary wing mode has the advantages of high lift-drag ratio, adjustable pitch, low failure rate, low cost, small influence of weather and the like. In order to improve the efficiency of material supply, reduce secondary loss and monitor materials in real time, a folding rotor wing and parachute drop air-drop buffer device is designed and manufactured, has the advantages of high repeated utilization rate, obvious deceleration, convenience and quickness in folding, easiness in finding at night, real-time path feedback and the like, and provides a novel solution for disaster relief and wartime supply.

Disclosure of Invention

The invention aims to provide a variable-pitch folding rotor wing parachute drop air-drop device designed based on the thin wing theory, aiming at the problems that the existing air-drop device is low in supply efficiency, high in cost, greatly influenced by climate and inconvenient to fold.

The invention is realized by the following technical scheme: a variable-pitch folding rotor wing parachute drop air-drop device designed based on a thin wing theory comprises a cargo hold, a wing head and a folding rotor wing;

the whole cargo compartment is of a hexahedral structure and comprises a base, connecting rods are arranged on six corners of the base, a compartment wall is arranged between every two adjacent connecting rods, a top plate is arranged at the upper end of each connecting rod, six connecting frames are arranged on the outer side of each top plate, and the center of each top plate is connected to the upper part of the cargo compartment through a connecting shaft and the connecting frames;

the wing head comprises a wing head box body, steering engine mounting plates in three directions are arranged inside the wing head box body, a bearing seat is arranged in the middle of the inside of the wing head box body, and the bearing seat is assembled and connected with a connecting shaft;

a supporting plate is arranged on the outer side of the bearing seat;

the folding rotor wing comprises a wing root and an outer wing, and the wing root section is connected with the outer wing section through a carbon tube; the side surface of the wing root is connected with an installation shaft, and the other end of the installation shaft is connected with a rudder angle in the wing head and a steering engine; the wing root and the outer wing are hinged by stainless steel 304 with torsion springs.

Preferably, corresponding lightening holes are designed on the bulkhead, the base, the top plate and the connecting frame under the premise of considering the material strength.

Preferably, the both ends fixed connection of mounting panel is on the inner wall of wing head box, the surface of mounting panel is provided with a set of big round hole, a set of rectangle trompil and a set of mounting hole, big round hole is used for the wiring of wing head inside, the mounting hole is used for installing folding rotor.

Preferably, the base and the top plate are both made of carbon fiber materials.

Preferably, the bulkhead is made of acrylic materials.

Preferably, the installation angle of the rotor wing is 8-12 degrees.

Preferably, the half span length of the rotor is 0.35m-0.5 m.

Compared with the prior art, the invention has the following advantages:

1. on the basis of the original traditional parachute drop air drop, the foldable rotor wing equipment is added, and the optimal parameter selection under the coupling of the installation angle and the half span length of the rotor wing is obtained through mathematical modeling and parameter optimization. Compared with the traditional parachute drop air drop, the air drop device with the self-rotary wing has the advantages of high lift-drag ratio, adjustable propeller pitch, low failure rate, low cost, small influence of weather and the like, and can further track the dropping speed and position of materials.

2. Compared with the traditional device, the buffer landing frame and the night visual lamp are additionally arranged, so that the device is easy to find at night, the completeness of the throwing device and materials is guaranteed, and a reasonable shock absorption buffer part is realized to reduce the impact of the falling of the device and prevent falling.

3. The invention can be widely applied to disaster relief and wartime supply, and can also be applied to dangerous investigation and survey sites when relevant instruments are loaded. The production mode shared by the military and the civil can be adopted in the market, and related sales permission can be given, so that the important function of mutual assistance and mutual assistance of the military and the civil is realized.

Drawings

FIG. 1 is a schematic view of the present invention;

FIG. 2 is a schematic top view of the present invention;

FIG. 3 is a schematic side view of the present invention;

FIG. 4 is a schematic structural diagram of the case of the present invention;

FIG. 5 is a schematic view of a wing head according to the present invention;

figure 6 is a schematic view of a portion of a folded rotor configuration according to the present invention;

FIG. 7 is a schematic view of a folded rotor configuration according to the present invention;

FIG. 8 is a schematic view of the rotor of the present invention under a force during a fall;

figure 9 is a schematic view of a rotor according to the present invention showing a cross-sectional airflow direction;

FIG. 10 is a schematic view of a rotor blade according to the present invention in cross-section under force;

FIG. 11 is a graph of the descent speed, linear speed of the rotor, and relative resultant velocity versus time of the present invention;

fig. 12 shows the effect of the half span length of the rotor at different mounting angles on landing speed.

Reference numbers in the figures: 1. a base; 2. a connecting rod; 3. a bulkhead; 4. a top plate; 5. a connecting frame; 6. a connecting shaft; 7. a bearing seat; 8. a wing head box body; 9. a support plate; 10. mounting a plate; 11. a wing root; 12. installing a shaft; 13. and an outer wing.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

As can be seen from fig. 1 to 9, the present invention provides an engineering technical solution, which is composed of a cargo hold, a wing head and a folding rotary wing. The composition and design of the three parts are described in detail below.

As can be seen from fig. 4, the overall shape of the cargo tank is a hexahedral structure, and the cargo tank is composed of a base 1 made of carbon fiber material, six corresponding connecting rods 2 and a bulkhead 3 made of acrylic material. For weight reduction design, corresponding weight reduction holes are designed on the premise that the bulkhead 3 and the carbon fiber base 1 both consider material strength. In order to ensure that the cargo hold is smoothly assembled with the wing head component corresponding to the wing head component shown in the figure 5, a top plate 4 made of carbon fiber materials is added on the cargo hold, and the center of the top plate 4 is connected with the cargo hold part through a connecting shaft 6 and six corresponding pairs of connecting frames 5; similarly, for weight reduction and buffer consideration, corresponding weight reduction holes are designed on the carbon fiber top plate 4 and the connecting frame 5.

The lower ends of six connecting rods 2 of the cargo hold penetrate through the base 1 to extend downwards, and the lower ends of the connecting rods 2 are provided with shock-absorbing buffering parts which are used for reducing the impact of the falling of the device and preventing the falling.

The outside of cargo hold still is equipped with the visual lamp at night for the device is easily found night, ensures to put in the device and the complete of goods and materials.

The rotor head of fig. 5 is a core device for mounting a rotor and placing a parachute, and the outside of the rotor head consists of a hexahedral wing head box body 8 and steering engine mounting plates 10 in three directions. Wherein, mounting panel 10 surface is provided with a set of great circle hole, a set of rectangle trompil and a set of mounting hole, through the inside wiring of the convenient wing head of great circle hole to can install folding rotor through the mounting hole. Further, a bearing housing 7 is centrally placed to be fitted with the connecting shaft 6 in fig. 4, and a support plate 9 is installed near the bearing housing 7 to prevent falling off and displacement in use. In the falling process, the rotation of the rotor head can drive the connected rotor to rotate.

The folded rotor portion is made up of the wing root 11 portion of figure 6 and the outer wing 13 section of figure 7. The wing root 11 section and the outer wing 13 section are connected through a carbon tube, the wing root 11 of the figure 6 is connected to the inside of the wing head through a mounting shaft 12, the mounting shaft 12 of the wing root 11 section is connected with a steering engine through a rudder angle, and three Futabas3003 steering engines are mounted on the mounting plate 10, so that the purpose of regulating and controlling the mounting angle and the pitch is achieved; the outer wing 13 section is connected with the wing root 11 section through a stainless steel 304 hinge with a torsion spring, and the folding effect is achieved. In the descending process, the outer wing section is unfolded automatically by the lifting force generated by the rotor wing and the upward airflow, and compared with connection modes such as a clamping plate and a bolt, the mode reduces the damage to the aerodynamic appearance of the rotor wing as much as possible, and the structure has large bearing capacity.

Description of the technology

In modeling the device kinematically, the rotor analysis uses a simplified flat plate flow-around method. The plate bypass flow is a simple and practical classical theoretical model for analyzing the wing lift resistance. The problem of the plate streaming can be solved according to the thin wing theory. For low-speed non-compressible flow, the lift drag equation is:

wherein L is rotor lift, D is the resistance that the rotor receives, U is rotor closing speed, S is the reference area of rotor, C_LIs a coefficient of lift, C_Dρ is the air density, which is the drag coefficient. The drag coefficient can be written as: c_D＝2sin²α. While the lift of the flat plate needs to be discussed in classification under the conditions of large attack angle and small attack angle: when the angle of attack exceeds a certain value (around 15 °), the flat plates undergo flow separation and the lift coefficient suddenly decreases, so that in a state of small angle of attack where no flow separation occurs, the lift coefficient can be represented as C_L2 pi sin α; under the condition of larger attack angle, the lift coefficient is reduced to C relative to the former due to the large-area flow separation_L2sin α cos α. In simulation analysis, stress conditions under a small attack angle are mainly considered in combination with reality.

The calculation of the lift resistance of the rotor wing is based on the calculation result of the plate flow, and the effect of the lift resistance induced by the blade tip is ignored because the aspect ratio of the rotor wing is relatively large. During rotor descent, velocity vector relationships and aerodynamic force analyses were plotted at three different positions of the rotor, as shown in FIG. 8, where v is_aIndicates the resultant velocity, v_rIndicating linear velocity of rotation, v_eIndicating the vertical drop velocity, F the aerodynamic force, and the three positions indicated by the superscript 123. In the area near the wing tip, the linear speed of rotation is high, so that the attack angle of the rotor is low, therefore, the generated aerodynamic force inclines backwards relative to the vertical direction, the horizontal component of the aerodynamic force hinders the rotation of the rotor, namely, corresponding to the driven area in fig. 8, the linear speed of rotation gradually decreases as the aerodynamic force approaches the root of the rotor, the local attack angle gradually increases, the direction of aerodynamic force gradually inclines forwards, and the rotor is gradually driven to rotate, such as the driving area in fig. 8; as the angle of attack continues to increase as the wing root section approaches, the rotor is about to enter a stall condition, such as the stall region of figure 8. For the sake of simplicity, we set the lift-drag coefficient at the mid-point of the rotor as the mean lift-drag coefficient of the rotor, taking into account the driving effect of the rotor aerodynamic forces on the rotor motion.

Because the gliding motion of the device in the horizontal direction does not influence the motion of the device in the vertical direction, only the motion process of the device in the vertical direction is considered in the establishment of the related motion equation, and the motion freedom degrees are two: vertical translation and rotation about the rotor mast. The vertical translation is that the device moves under the action of the lift force of the rotor wing, the resistance force and the gravity of the parachute and the cargo hold; the rotor rotating around the main shaft does accelerated motion under the action of driving force. The airflow direction and the section stress analysis when the rotor rotates are shown in fig. 9 and fig. 10.

Based on the above analysis, the equation of motion of the rotor is established as:

Mg-(Dsinr+Lcosr)＝Ma

R(Lsinr-Dcosr)＝Jβ

wherein M and J are total mass of the device and rotational inertia around the main shaft, alpha and beta are acceleration of the device in the vertical direction and angular acceleration of the device rotating around the main shaft, g is gravitational acceleration, R is half span length of the rotor, L and D are lift force and resistance of the rotor, and R is sum of an attack angle alpha of the rotor and a mounting angle theta, namely included angle of the synthetic airflow and the rotating relative motion airflow.

The cabin body part is divided into a parachute and a cargo hold, the parachute is fixedly connected with the rotor wing, and extra resistance of air serving as fluid to moving objects is increased in the falling process. To simplify the calculations, the unfolded parachute is considered a hemisphere, the resistance experienced during the descent of the hemisphere is taken into account and the flow in the flow field is considered laminar. Considering the factors of the surface area shape, smoothness and the like, the resistance formula can be written as f₁＝k₁ρA₁V²，A₁For the parachute cross-sectional area, k1 is the drag coefficient (k1 ≈ 0.42, assuming Re ≈ 10)⁴) Assuming that the resistance coefficient does not change with the Reynolds number, and V is the falling speed; in a similar way, the cargo hold is also influenced by air resistance in the falling process, and the cargo hold is simplified into a cylindrical cargo hold by applying the above-mentioned assumption, wherein the resistance equation of the cylindrical cargo hold is as follows: f. of₂＝k₂ρA₂V²A2 is the cross-sectional area of the cargo hold, k₂Is the coefficient of resistance (k)₂0.82, assuming Re 10⁴)。

First, we choose the following standard parameters to simulate the fall of the device. The parameters are estimated according to the mass and length of the manufacturing material, the whole device is unloaded by 2.5kg, the initial height is set to be 30m, the half-span length of the rotor wing is 0.45m, the chord length of the rotor wing is 0.15m, the installation angle of the rotor wing is 8 degrees, and the rotary inertia of the rotor wing is calculated according to the mass and the length of the manufacturing materialAnd (3) calculating, solving a differential equation set considering the resistance of the cargo hold and the parachute, and drawing the relation between the vertical falling speed V, the linear speed wR of the rotor wing, the relative airflow resultant speed U and the falling time, wherein the falling speed V is approximately equal to 8.75m/s as can be known from the graph of FIG. 11.

For an air-drop device, the falling speed of the whole device is expected to be low, so that the structural damage to the device caused by falling impact can be reduced as much as possible, the average speed of the falling process is improved, and the falling time in the air is shortened, so that the influence of horizontal motion on the whole device is reduced, and the horizontal motion is easily influenced by the environment in actual air-drop falling. Therefore, the landing speed and the landing time are considered in the parameter optimization, and an optimal solution is explored between the landing speed and the landing time. For the landing speed and the landing time of the equipment, the landing speed and the landing time mainly depend on the installation angle and the half-span length of a rotor wing, an initial range is set for the two parameters, the installation angle is set to be 2-15 degrees, the half-span length of the rotor wing is set to be 0.2-0.5 m, and single-parameter and double-parameter joint optimization are respectively carried out on the two parameters.

Considering a single parameter optimization of the setting angle, i.e. considering the effect of the rotor setting angle on the landing speed and the fall time of the device, the mass of a single rotor is about 300 g.

Table 1 results on the mounting angle optimization

Secondly, considering the half-span length factor of the rotor, the half-span length of the rotor is optimized, and the numerical result of the half-span length of the rotor from 0.2m to 0.5m is as follows:

TABLE 2 results for half span optimization

Half display length (m)	Landing speed (m/s)	Time of descent(s)
			0.2	23.6791	2.5231
0.25	23.2661	2.5532
			0.3	22.5562	2.6001
0.35	20.9660	2.6878
			0.4	5.7135	3.8060
0.45	5.7353	6.2989
			0.5	5.7436	7.4403

As can be seen from the data in the table, with the increase of the half-spread length, the landing speed is reduced firstly and then the landing speed is increased by a small amplitude; the falling time is increased by a small margin and then increased by a large margin.

From the data in the table, when the variation range of the installation angle is 2-6 degrees, the influence of the half-span length of the rotor wing is small in the range, although the theoretical landing speed reaches a desired small value, the falling time of the whole device is still long, and the influence of the installation angle is a main factor; when the installation angle is in the range of 13-15 degrees, the falling time is further reduced, but the falling speed is too high, and the influence factor of half-span length of the rotor wing is small. For the half-span length of the rotor wing, when the value range of the half-span length of the rotor wing is 0.2m-0.3m, the landing speed of the device is nearly the speed value of free falling from the height of 30m, so that when the span length of the rotor wing is too small, the generated lift resistance is small, and the influence on the falling process of the device is approximately negligible. In summary, the initial range of parameters for the joint optimization considers a setting angle of 8 ° -12 ° and a rotor half span length of 0.35m-0.5 m.

Fig. 12 shows a relationship between landing speed and half span length of the rotor, and a relationship between landing time and half span length of the rotor, which correspond to a fixed mounting angle. As can be seen from the figure, the larger the installation angle is, the integral floor falls

Further analysis shows that the installation angle is 9 degrees, and the turning point is when the half-span length R of the rotor wing is 0.4 m. When R is larger than 0.4m, the change trend of the landing speed is smaller, and the change trend of the falling time is larger; when R is less than 0.4m, the change trend of the landing speed is larger, and the change trend of the falling time is smaller. Therefore, when the installation angle is 9 degrees and the half-span length R of the rotor wing is 0.4m, the falling time and the landing speed reach the optimal solution of joint optimization.

The dynamic equation of the whole system can be further rewritten by comprehensively considering the resistance influence of the cargo hold and the parachute as follows:

it is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation. The use of the phrase "comprising one of the elements does not exclude the presence of other like elements in the process, method, article, or apparatus that comprises the element.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.