阅读说明：本技术 一种共轴同向旋转的双扑旋翼飞行器 (Coaxial homodromous double-flapping rotor aircraft ) 是由 周超 李港 褚松涛 吴江浩 于 2021-08-24 设计创作，主要内容包括：为了解决现有扑旋翼飞行器单平面构型翼载荷变化剧烈、飞行器气动效率低,多平面构型下方翼气动性能受尾迹影响性能损失的问题,本发明提出了一种共轴同向旋转的双扑旋翼飞行器。该飞行器上下两对翼同轴布置,同频率反向竖直拍动并同向同速旋转,通过在两翼打开合拢的过程中增加水平方向的推力矩,实现翼旋转力矩平衡状态下获得更快的被动旋转速度,实现了升力增加和气动效率提升。(The invention provides a double-flapping rotary wing aircraft capable of rotating coaxially and in the same direction, and aims to solve the problems that the load of a single-plane configuration wing of the existing flapping rotary wing aircraft changes violently, the aerodynamic efficiency of the aircraft is low, and the aerodynamic performance of a lower wing of a multi-plane configuration is affected by a wake and the performance is lost. The upper and lower pairs of wings of the aircraft are coaxially arranged, flap vertically in the same frequency and in the opposite direction and rotate at the same speed, and the thrust moment in the horizontal direction is increased in the process of opening and closing the two wings, so that the faster passive rotation speed is obtained in the state of the balance of the rotation moment of the wings, and the increase of the lift force and the improvement of the pneumatic efficiency are realized.)

1. A double-flapping rotor aircraft rotating coaxially and in the same direction is characterized by comprising an upper wing, a lower wing, a base, a transmission device and a micro motor;

the upper wing and the lower wing are in a pair, are coaxially arranged, are respectively installed at the upper end and the lower end of the transmission device, vertically flap together with the transmission device at the same flapping frequency, and passively rotate at the same speed and in the same direction in the upper horizontal plane and the lower horizontal plane under the action of thrust moment generated by flapping;

the upper wing and the lower wing flap reversely in a flapping period, when the upper wing finishes flapping, the two wings are attached, when the flapping process finishes, the two wings are closest, when the upper wing starts flapping, the two wings are quickly opened, and in the process, the thrust and the thrust moment in the horizontal direction are increased by utilizing the opening and closing effect, so that the upper wing and the lower wing can obtain higher rotating speed at the same time, the generation of lift force is enhanced, and the aerodynamic efficiency is improved.

2. A co-axial co-rotating dual-flapping rotary-wing aircraft according to claim 1, wherein the upper wing and the lower wing are identical in structure and each comprise a main beam, two auxiliary beams and a wing membrane; when the upper wing and the lower wing are initially installed, when the main beams of the upper wing and the lower wing flap to the horizontal plane, the included angle between the plane where the upper wing and the lower wing are located and the horizontal plane is designed to be between 15 degrees and 25 degrees; the upper wing is arranged in an anti-symmetric manner about the rotating shaft of the upper wing, and the installation requirement of the lower wing is the same as that of the upper wing.

3. A co-axial co-rotating dual-flapping rotary-wing aircraft according to claim 1, wherein the flapping amplitudes of the upper wing and the lower wing are the same, and to ensure that the wings fit over a larger area when they are closest, the opening and closing effect is significant, and the flapping amplitudes of the upper wing and the lower wing are limited to 20 ° to 30 °.

4. A co-axial co-rotating double-flapping rotary-wing aircraft according to claim 1, wherein the distance between the tips at the end of the flapping of the upper wing is not more than 4 times the average geometric chord length of the wings of said upper wing, in order to increase the horizontal thrust to achieve high rotational speed by opening and closing effect during the transition from flapping of the upper wing to flapping of the lower wing.

5. A co-axial co-rotating dual-flapping rotary-wing aircraft according to claim 1, wherein said transmission comprises a main shaft gear, a speed reducer, and an actuator;

the spindle gear is fixed on the output shaft of the micro motor and is in meshing transmission with the speed reducer to reduce the speed of the high-speed rotary motion output by the motor; the actuating mechanism comprises an oscillating component, a flapping component and a rotating component; the speed reducer is connected with the oscillating assembly of the actuating mechanism, and the circular motion after speed reduction is changed into vertical oscillation of the oscillating assembly; the oscillating assembly drives the flapping assembly to drive the upper wing and the lower wing to perform symmetrical reverse reciprocating flapping motion, namely when the upper wing performs upward flapping motion, the lower wing performs downward flapping motion synchronously.

6. A co-axial co-rotating dual-flapping rotary-wing aircraft according to claims 1 and 5, wherein the upper wing and the lower wing are passively rotated in conjunction with the actuator rotating assembly, and are restrained by the rotating assembly to maintain the upper wing and the lower wing rotating at the same speed.

Technical Field

The present invention relates to the field of micro-aircraft, and in particular, but not exclusively, to a double-flapping rotary-wing aircraft rotating coaxially and in the same direction.

Background

With the continuous maturation of the traditional aircraft design technology and the great progress of the microelectronic technology since the nineties of the twentieth century, the concept of micro aircraft has been proposed and its rapid development has been promoted. The micro aircraft has small volume, light weight and strong maneuverability, has wide application prospect in the aspects of national safety and national economic construction, and can be used for investigation, exploration, assistance in rescue and the like in complex environments. Currently, the research of the micro air vehicle focuses on the field of the bionic micro air vehicle.

At present, people gradually and deeply know the biological flying principle, and a plurality of bionic micro aircrafts are constructed by imitating the biological flying. With the improvement of the technology, people also actively break through the limitation of the biological flight movement physiological structure, and in order to design an aircraft with higher performance, the biological flight principle and the traditional aircraft pneumatic principle are combined to design a composite micro aircraft layout, wherein one of the composite micro aircraft layout is a flapping rotor wing. The flapping rotor wing layout integrates two motions of a flapping wing and a rotor wing, the wings actively and vertically flap and passively rotate when moving, and therefore the layout has the advantages of high lift force of the flapping wing layout moving under the low Reynolds number and high aerodynamic efficiency of the rotor wing layout.

In the past, a monoplanar configuration has been proposed for a flapping-rotor aircraft, such as the patent "a flapping-rotor aircraft based on piezoelectric drive and a driving method" (patent No. ZL 201711019042.X) and the patent "a micromachine slide rail type controllable flapping-rotor aircraft" (patent No. ZL 201511021309. X). The flapping rotor wing mainly depends on the downward flapping process to generate lift force, and the upward flapping process has small contribution to the lift force, so that the load of the aircraft wing is high under the condition of high load generation, the transient force peak value difference of the upward flapping process and the downward flapping process of the wing is large, the aerodynamic force changes violently, the power consumption is high, and the efficiency is low. To solve this problem, some designs have proposed the concept of multiple wings, such as the patent "a coaxial counter-rotating double flapping rotor mechanism" (patent No. ZL 201910332059.3) which proposes the solution of multiple pairs of wings in order to reduce the wing load and aerodynamic force fluctuation by increasing the number of wings. In the scheme, the multiple wings rotate coaxially and reversely, the lower wing is completely positioned in the wake of the upper wing, the lower wing is very strongly interfered by the downward washing flow of the upper wing, and the lower wing has lower pneumatic efficiency.

Past studies of flow interference between multiple wings at low reynolds numbers have revealed that multiple wings may gain aerodynamic advantage from wing interference, one effect being the opening and closing effect. The opening and closing effect may enhance the aerodynamic forces perpendicular to the opening and closing direction during the opening and closing of the wings. Therefore, in order to address the problem of how much lower wing would not benefit from upper wing interference in previous multi-planar flapping rotor configurations, it is necessary to explore other flapping rotor designs in an attempt to achieve a more optimal performance aircraft through the application of the multi-wing interference effect.

Disclosure of Invention

The invention provides a double-flapping rotor aircraft capable of rotating coaxially and in the same direction, and aims to solve the problems that the load of a single-plane configuration wing of the existing flapping rotor aircraft changes violently, the aerodynamic efficiency of the aircraft is low, and the aerodynamic performance of a lower wing of a multi-plane configuration is affected by the wake of an upper wing, so that the performance is lost. The upper and lower pairs of wings of the aircraft flap reversely at the same frequency and rotate at the same speed in the same direction, and the thrust moment in the horizontal direction is increased in the process of opening and closing the two wings, so that the faster passive rotation speed is obtained under the condition of balanced rotation moment of the wings, and the increase of lift force and the improvement of aerodynamic efficiency are realized.

The opening and closing mechanism applied in the invention is one of flapping wing high lift mechanisms, and the action principle is as follows: the two flapping wings are close to each other and attached when the upward flapping process is finished, and are quickly opened when the downward flapping process is started. When the two wings are quickly opened after being closed, a ring amount is generated on each wing; because the two wings are opened without the shedding of the starting vortex, the delay effect of the shedding of the starting vortex on the maximum lift force is avoided, and the wings generate larger aerodynamic force immediately at the beginning of flapping. The opening and closing mechanism mainly increases the force perpendicular to the opening and closing movement direction, and insects mainly apply the mechanism to increase the lift force, and researches show that the average lift force can be increased by about 8-19% by virtue of the opening and closing mechanism. In the flapping-rotor wing, the flapping rotor wing vertically flaps, so that the upper wing and the lower wing are designed to flap reversely, namely the lower wing performs upward flapping motion when the upper wing flaps downward, and the opening and closing motion is designed in the vertical direction, so that the effect is mainly used for enhancing the thrust and the thrust moment in the horizontal direction so as to improve the rotating speed of the flapping rotor wing. An increase in the speed of rotation of the flapping rotors further enhances lift generation and increases aerodynamic efficiency.

The invention relates to a coaxial homodromous double-flapping rotor aircraft which is characterized by comprising an upper wing, a lower wing, a base, a transmission device and a micro motor. The micro motor is arranged on the base, outputs power, and drives the transmission device to drive the upper wing and the lower wing to flap vertically and reciprocally. The upper wing and the lower wing are in a pair, are coaxially arranged, are respectively installed at the upper end and the lower end of the transmission device, vertically flap together with the transmission device at the same flapping frequency, and passively rotate at the same speed and in the same direction in the upper horizontal plane and the lower horizontal plane under the action of thrust moment generated by flapping.

The upper wing and the lower wing have the same structure and respectively comprise a main beam, two auxiliary beams and a wing membrane. One end of the main beam is fixedly connected in a mounting hole of the rocker arm at the tail end of the transmission device and connected with the wing root ends of the two auxiliary beams, and the main beam and the auxiliary beams are adhered to the wing membrane. When the upper wing and the lower wing are initially installed, when the main beams of the upper wing and the lower wing flap to the horizontal plane, included angles between planes of the upper wing and the lower wing and the horizontal plane are designed to be 15-25 degrees, the pair of upper wings are arranged in a reverse symmetry mode relative to a rotating shaft, and the installation requirements of the lower wing are the same as those of the upper wing.

The base is used for fixing the micro motor and the transmission device, wherein a cylindrical cavity is formed in the upper surface of the base and used for fixing the micro motor, and a supporting structure is arranged behind the cylindrical cavity and used for positioning and supporting the transmission device speed reducer and the executing mechanism.

The micro motor is fixed in the reserved cylindrical cavity of the base.

The transmission device comprises a main shaft gear, a speed reducer and an actuating mechanism. The main shaft gear is fixed on the output shaft of the micro motor and is in meshing transmission with the speed reducer to reduce the speed of the high-speed rotating motion output by the motor. The actuating mechanism comprises an oscillating component, a flapping component and a rotating component. The speed reducer is connected with the oscillating assembly of the executing mechanism, and the circular motion after speed reduction is changed into the vertical oscillating motion of the oscillating assembly. The oscillating assembly drives the flapping assembly to drive the upper wing and the lower wing to perform reverse reciprocating flapping motion, namely, when the upper wing performs upward flapping motion, the lower wing performs downward flapping motion synchronously. The flapping amplitudes of the upper wing and the lower wing are the same, and in order to ensure that the joint area is large enough when the two wings are close to each other and the opening and closing effect is obvious, the flapping amplitudes of the upper wing and the lower wing (defined as the angle formed between the positions of the main beam when the upper wing or the lower wing reaches the upper limit position and the lower limit position in one flapping cycle) are limited to be 20-30 degrees. The upper wing and the lower wing start to passively rotate along with the rotating component of the actuating mechanism after generating thrust moment through flapping motion, and the rotating component limits and maintains the upper wing and the lower wing to rotate at the same speed.

The upper wing and the lower wing flap reversely in a flapping cycle, namely when the upper wing flaps downwards, the lower wing flaps upwards, when the upper wing flaps downwards, the two wings are attached to each other, and when the lower wing flaps downwards, the two wings are closest to each other, and when the upper wing flaps upwards, the two wings are opened quickly. In order to increase the horizontal thrust to obtain high rotating speed by utilizing the opening and closing effect in the process of changing the upper wing from downward flapping to upward flapping, the distance between two wing tips at the end of the downward flapping process of the upper wing is not more than 4 times of the average geometric chord length (defined as the area of a single wing divided by the span length of the single wing) of the upper wing.

The working principle that the motion process of a coaxial homodromous double-flapping rotor aircraft and the pneumatic performance of upper and lower wings is improved by utilizing an opening and closing effect is as follows: after the power is supplied to the aircraft, the micro motor outputs high-speed rotation, the upper wing and the lower wing are driven by the oscillating assembly and the flapping assembly to flap reciprocally after the speed is reduced by the speed reducer, and after the flapping motion generates a thrust moment, the upper wing and the lower wing both maintain the same-direction and same-speed rotation by the rotating assembly until the rotation is stable. In a complete flapping cycle, the motion relation and aerodynamic force generation process between the upper wing and the lower wing is as follows:

(1) when the upper wing beats downwards, the lower wing beats upwards, the upper wing and the lower wing generate respective aerodynamic force through flapping and rotating motion, and the working process of the flapping wing is similar to that of the traditional single-plane flapping rotor wing;

(2) when the lower flapping motion of the upper wing is finished and the upper flapping motion is finished, the upper wing and the lower wing are gradually jointed and folded to be quickly opened, the aerodynamic force of the wings in the horizontal direction is obviously increased, and the upper wing and the lower wing can obtain larger horizontal rotation moment;

(3) when the upper wing continues to perform upward flapping, the lower wing performs downward flapping, and the mutual interference between the two separated wings is reduced until a new flapping cycle begins;

(4) after the wings obtain higher horizontal rotation moment, the rotation speeds of the two wings are obviously improved, and although the rotation moments generated by the upper wing and the lower wing are different due to the influence of factors such as machining and manufacturing, wake interference and the like, the rotation speed of the upper wing and the rotation speed of the lower wing are limited to the same value by the rotating assembly, so that the opening and closing movement can occur in each flapping cycle.

The invention has the advantages that:

(1) according to the coaxial homodromous double-flapping rotary wing aircraft, the upper wing and the lower wing are opened and closed in one flapping cycle, the thrust and the rotating moment in the horizontal direction of the wings are increased, and the wings can obtain higher rotating speed, so that the lift force and the aerodynamic efficiency of the wings are improved.

(2) Compared with the flapping rotor craft with a single-plane configuration, the double-flapping rotor craft with coaxial and homodromous rotation has the advantages that the high rotation speed of the wings increases the lift force of the wings in the upward flapping process, so that the load change of the wings is slowed down; the increase of the number of the wings reduces the load of the single wing, and improves the aerodynamic efficiency of the aircraft.

(3) Compared with the conventional coaxial double-flapping rotor aircraft, the coaxial homodromous double-flapping rotor aircraft provided by the invention fully utilizes the flow interference effect among multiple wings, and avoids the problem that the multiple wings interfere and cannot provide pneumatic benefits in the traditional multiple wing arrangement scheme.

Drawings

FIG. 1 is a general schematic view of a co-axial co-rotating dual-flapping rotary-wing aircraft of the present invention;

FIG. 2 is a schematic view of the upper wing of a co-axial co-rotating dual-flapping rotary-wing aircraft of the present invention;

FIG. 3 is a schematic view of the base of a co-axial co-rotating dual-flapping rotorcraft according to the present invention;

FIG. 4 is a schematic view of the transmission mount of a co-axial co-rotating dual-flapping rotorcraft according to the present invention;

figure 5 is a schematic view of the micro-motors of a co-axial co-rotating dual-flapping rotorcraft according to the present invention;

in the figure:

1-upper wing 2-lower wing 3-base

4-transmission device 5-micro motor

101-main beam 102-short beam 103-oblique beam

104-wing membrane 401-main shaft gear 402-big gear

403-driving connecting rod 404-inner rod 405-big support

406-big bearing 407-small support 408-small bearing

409-wing connecting rod 410-rocker arm

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below. The present invention will be described in further detail with reference to the accompanying drawings and examples.

Fig. 1 is an overall schematic diagram of a coaxial homodromous double-flapping-rotor micro aircraft, which comprises an upper wing 1, a lower wing 2, a base 3, a transmission device 4 and a micro motor 5.

Fig. 2 shows an exemplary embodiment of the upper wing 1 and the lower wing 2, the one main girder 101 and the two auxiliary girders 102, 103 being made of carbon fiber rods, and the wing membrane 104 being made of polyethylene film. When the initial installation is carried out, when the main beams of the upper wing 1 and the lower wing 2 are positioned in a horizontal plane, the included angle between the plane of the upper wing 1 and the plane of the lower wing 2 and the horizontal plane is designed to be between 15 degrees and 25 degrees, and the cylinder at the root of the main beam 101 is fixedly installed in the reserved hole of the rocker arm 410 of the transmission device 4. As shown in fig. 1, a pair of upper wings 1 are arranged antisymmetrically about a rotation axis, and the lower wings 2 are installed as required for the upper wings. The flapping amplitudes of the upper wing 1 and the lower wing 2 are the same, and in order to ensure that the joint area is large enough when the two wings are close to each other and the opening and closing effect is obvious, the flapping amplitudes of the upper wing 1 and the lower wing 2 are limited to be 20-30 degrees. In order to increase the horizontal thrust by utilizing the opening and closing effect to obtain high rotating speed in the process of changing the upper wing 1 from downward flapping to upward flapping, the distance between the wingtips of the upper wing 1 and the lower wing 2 is not more than 4 times of the chord length of the upper wing 1 when the downward flapping process of the upper wing 1 is finished.

Fig. 3 shows an exemplary embodiment of the base 3 integrally made of a resin material or a polylactic acid material by 3D printing. The base 3 is of a symmetrical structure, a cylindrical cavity is reserved in the center of the upper surface, and gear racks are symmetrically arranged on the upper side and the lower side of the rear of the cavity respectively to play a role in supporting the large gears 402a and 402 b. The rear side of the frame is reserved for positioning the main shaft gear 401. Two sleeves are symmetrically arranged in the vertical direction behind the positioning rod, and are respectively provided with a central hole and a side groove for limiting the inner rods 404a and 404 b.

Fig. 4 shows an exemplary embodiment of the transmission 4, comprising a main shaft gear 401, a reducer (large gears 402a and 402b), an oscillating assembly (transmission links 403a and 403b, inner rods 404a and 404b), a flapping assembly (wing links 409a-d, rocker arms 410a-d), a rotating assembly (large mount 405, large bearings 406a and 406b, small mounts 407a and 407b, small bearings 408a and 408 b). The inner rod 404 is made of a light carbon fiber rod, the large bearing 406 and the small bearing 408 are made of light metal bearings, and the rest parts are integrally made of resin materials or polylactic acid materials through 3D printing. The main shaft gear 401 and the large gears 402a and 402b are engaged in the same plane and perpendicular to the upper and lower symmetrical planes of the base 3. The positions of the large gears 402a and 402b maintain two eccentric holes and are centrosymmetric about the index center of the main shaft gear 401. One end of the transmission connecting rod 403 is connected with an eccentric hole of the large gear 402 by a rivet, and the other end of the transmission connecting rod passes through a sleeve side wall groove of the base 3 by the rivet to be connected with the inner rod 404. The inner rod 404 is disposed within the sleeve of the base 3 and is vertically slidable within the sleeve. The large support 405 is arranged on the top of the sleeve of the base 3 and is hinged with the wing connecting rod 409, and the large bearing 406 is arranged in a reserved hole of the large support 405. The small support 407 is arranged on the top of the inner rod 404 and is hinged with the rocker arm 410, and the small bearing 408 is arranged in a reserved hole of the small support 407. The wing link 409 is hinged to a rocker arm 410. The transmission device 4 is used for converting high-speed circular motion output by the motor into up-and-down motion of the oscillating assembly through speed reduction of the speed reducer, driving the flapping assembly and driving the upper wing 1 and the lower wing 2 to carry out symmetrical reverse reciprocating flapping motion; the upper wing 1 and the lower wing 2 start to rotate around the rotating assembly after generating thrust moment through flapping motion, and maintain the same-speed rotation through the limitation of the rotating assembly.

Fig. 5 shows an exemplary embodiment of the micromotor 5. The micro motor 5 is arranged in a reserved cylindrical cavity of the base 3, and an output shaft is fixedly connected with a main shaft gear 401 in the transmission device 4.

The operation of a co-axial co-rotating double-flapping rotary wing aircraft according to the invention is described with reference to fig. 1-5. After the power is supplied to the aircraft, the micro motor 5 outputs high-speed circular motion, the speed is reduced through the transmission device 4 and the high-speed circular motion is converted into reverse reciprocating flapping motion of the upper wing 1 and the lower wing 2, torque for driving the wings to rotate is generated, the upper wing 1 and the lower wing 2 both rotate at the same direction and the same speed through the rotating assembly until the rotation is stable, and lift force is generated. In one period, the upper wing 1 and the lower wing 2 are bound to approach each other once, that is, when the downward flapping motion of the upper wing 1 is finished and the upward flapping motion is finished. At the moment, the upper wing 1 and the lower wing 2 are gradually fitted and folded to be quickly opened, aerodynamic force in the horizontal direction of the wings is obviously increased in the process under the action of an opening and folding effect, the upper wing 1 and the lower wing 2 also obtain larger horizontal rotating moment, and the rotating speed of the two wings is obviously improved after the wings obtain higher horizontal rotating moment, so that the incoming flow dynamic pressure is increased, and the generation of higher lifting force is facilitated.

Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.