CN113665806B - Flapping-wing and rotor wing combined type micro air vehicle - Google Patents

Abstract

The invention provides a composite type miniature aircraft of flapping wings and rotor wings, which aims to solve the problems that the traditional flapping-rotor aircraft has too high wing load and has larger unbalanced aerodynamic moment and friction moment when the wing is flown forward to drive a fuselage to rotate. The main aerodynamic surface of the aircraft is a pair of flapping rotors, a pair of passively rotating rotors are only introduced below the plane of the flapping rotors, the small rotor rotating shaft is consistent with the flapping rotor rotating shaft, and the reverse rotation is realized under the combined action of the lower washing airflow and the forward flying airflow of the flapping rotors so as to supplement the lift force of the aircraft, reduce unbalanced moment and friction moment, thereby improving the lift force of the aircraft and reducing the design difficulty of a control system.

Description

A flapping wing and rotor composite micro-aircraft

technical field

The present invention relates to the field of micro-aircraft, specifically but not exclusively, to a micro-aircraft with flapping wings and rotors.

Background technique

With the continuous advancement of microelectronics technology in recent years, the miniaturization of aircraft has gradually become the research focus in the field of aviation. MAVs are small in size, light in weight, strong in maneuverability, and low in cost. They can be used in large quantities after mass production, and have broad application prospects in military and civilian applications. They can be used for reconnaissance, exploration, and rescue assistance in complex environments. The focus of current micro-aircraft research is mostly concentrated in the field of bionic micro-aircraft.

The flapping rotor layout is a kind of layout of the flapping wing and rotor composite micro air vehicle designed by combining the principle of biological flight with the aerodynamic principle of traditional aircraft. The flapping rotor layout combines the two movements of the flapping wing and the rotor. During the movement, the wings actively flap vertically and rotate passively. Therefore, this type of layout has both the high lift advantage of the flapping wing layout at low Reynolds number and the high aerodynamics of the rotor layout. Features of efficiency.

In the past, people proposed various designs of flapping rotorcraft, such as the patent "a flapping rotorcraft based on piezoelectric drive and its driving method" (patent No. ZL 201711019042.X) and the patent "a micromechanical slide rail type Control flapping rotorcraft" (Patent No. ZL 201511021309.X). These flapping rotor designs have certain problems in the aerodynamic performance scheme, which are mainly reflected in the following aspects: First, the flapping rotor mainly relies on the down-shooting process to generate lift, while the up-shooting process contributes little to the lift. Therefore, the greater the wing load of a single flapping rotor, the more obvious the difference between the up and down beat loads, and the greater the requirement for the instantaneous power of the motor. The second is that when the flapping rotor is flying forward, one wing is in the forward stage, while the other side is in the backward stage. The lift of the wing in the forward stage is relatively large, while the lift of the wing in the backward stage is small. The difference in lift between the two sides It will cause significant unbalanced moment, which requires high control system design. The third is that although the rotation of the flapping rotor is driven by aerodynamic torque and is passive, there is still friction torque driving the fuselage to rotate due to the friction between the mechanism components, so the friction torque needs to be overcome during design.

The coaxial counter-rotating wing design scheme is an effective way to solve the above problems. For example, the patent "A Coaxial Reverse Double Flapping Rotor Mechanism" (patent No. ZL201910332059.3) proposes a multi-pair wing scheme, in order to pass the number of wings The increase to reduce wing loading and aerodynamic fluctuations eliminates the unbalanced moment between the front and rear wings. However, in this scheme, the multi-wings rotate coaxially and reversely, and the two sets of wings are of the same size. During the movement, the lower wing is in the wake of the upper wing, and is always disturbed by the downwash airflow of the upper wing. The aerodynamic efficiency is lower than that of the upper wing. In addition, the two sets of wings are actively driven wings, so the aircraft needs to drive the two sets of wings to move at the same time, and the requirements for mechanism transmission and driving energy are also high. For this reason, it is still necessary to explore the multi-wing design scheme of simpler flapping wing and rotor compound micro-aircraft to solve the above three problems.

Contents of the invention

In order to solve the problems of the traditional flapping rotor such as flapping wing and rotor composite micro-aircraft with too high wing load, unbalanced aerodynamic moment generated by the wing when flying forward, and frictional torque driving the fuselage to rotate, the present invention proposes a flapping wing and rotor Composite micro-aircraft. The main aerodynamic surface of the aircraft is still a pair of flapping rotors, and a pair of passive horizontally rotating small rotors are introduced below the rotation plane of the flapping rotors. The rotation axis of the small rotors is consistent with the rotation axis of the flapping rotors. Under the joint action of the downwash airflow of the flapping rotor and the forward flying flow, the reverse rotation realizes the supplement to the lift of the aircraft, reduces the unbalanced moment and the frictional moment, so as to reduce the lift generation requirement of the flapping rotor and reduce the difficulty of flight control of the aircraft, thereby Improve aircraft performance.

Specifically, the present invention is a flapping wing and rotor composite micro-aircraft, which is characterized in that it includes a base, a transmission device, a micro motor, a flapping rotor, and a small rotor.

The base is used to fix the micro motor and the transmission device, wherein a cylindrical cavity is opened on the upper surface of the base for fixing the micro motor, and the back of the cylindrical cavity is a support structure for positioning and supporting the reducer gear of the transmission device and the inner rod of the actuator.

The micro motor is fixed in the reserved cylindrical cavity of the base. The micro-motor outputs power, and the transmission device drives the flapping rotor to vertically reciprocate and passively rotate.

The flapping rotor is installed on the top of the transmission device, and is flapped and rotated together by the flapping assembly and the rotating assembly of the transmission device. The flapping rotor comprises a main beam, two auxiliary beams and a wing membrane. One end of the main beam is fixedly connected to the end of the beating assembly of the transmission device, and connected to the wing root ends of the two auxiliary beams, and the main beam and the auxiliary beam are pasted on the membrane. During the initial installation, when the main beam of the flapping rotor flaps to the horizontal plane, the angle between the plane where the flapping rotor is located and the horizontal plane is designed to be between 10° and 15°. The main purpose of setting this angle is to increase the rotation speed of the flapping rotor itself To increase the size of the downwash airflow to drive the small rotor to rotate, on the other hand, the angle of attack of the flapping rotor is set near the angle of attack for high lift generation to ensure high lift generation.

The small rotor is a lightweight film structure, coaxial with the flapping rotor, installed under the flapping rotor, and only performs rotational motion. The horizontal installation direction of the small rotor is opposite to that of the flapping rotor to realize reverse rotation. The wingspan of the small rotor is 1/2-1/3 of the wingspan of the fluttering rotor, so as to ensure that the small rotor has a small moment of inertia to rotate quickly to generate lift. The aspect ratio of the small rotor is 5-7, which ensures the high aerodynamic efficiency of the small rotor. The rotation plane of the small rotor is horizontal, and the distance from the rotation plane of the flapping rotor is within 0.5-0.75 times the length of the flapping rotor, and its rotation axis is the same as that of the flapping rotor. The root of the small rotor is bonded to the rotating assembly of the actuator to realize the reverse rotation around the rotation axis and the flapping rotor.

The transmission device includes a main shaft gear, a reducer and an actuator. The main shaft gear is fixed on the output shaft of the micro-motor, and is engaged with the reducer to reduce the high-speed rotational motion output by the motor. The actuator includes an oscillating component, a flapping component and a rotating component. The speed reducer is connected with the oscillating component of the actuator, and converts the decelerated circular motion into the up and down vertical oscillation of the oscillating component. The oscillating component drives the flapping component to drive a pair of fluttering rotors to perform a reciprocating flapping motion; the flapping rotors generate thrust torque through the flapping motion and then start to rotate around the rotating component, and the small rotors are combined by the downwash airflow of the flapping rotors and the front-flying incoming flow. The action rotates around the rotating assembly, but in the opposite direction to the flapping rotor. The rotating assembly can realize the flapping rotor and the small rotor rotating around the same rotating shaft in opposite directions and at different speeds.

The motion process of a flapping-wing and rotor composite micro-aircraft is as follows: after the aircraft is powered, the micro-motor outputs high-speed rotation, and after being decelerated by the reducer, the flapping rotor is driven by the oscillating component and the flapping component to perform reciprocating flapping, and the flapping motion is generated. After a thrust moment, it starts to rotate. During hovering flight, the passive rotation of the small rotor is driven by the flapping rotor wake airflow, while in forward flight it is driven by the joint action of the flapping rotor wake airflow and the forward flying flow. This feature is similar to a windmill or a windmill toy for children. Since the flapping rotor and the small rotor are horizontally installed in opposite directions, they rotate in opposite directions when they move.

A flapping wing and rotor composite micro-aircraft uses a small rotor to improve aerodynamic performance and reduce the difficulty of flight control. The working principle is as follows:

(1) Compared with the traditional single-pair flapping rotor layout, in the present invention, a small rotor is added below the flapping rotor. The design of the small rotor with a light moment of inertia and a large aspect ratio ensures that the rotor can move forward under the action of the incoming flow from above. Rapid rotation to generate additional lift, resulting in reduced flapping rotor loading;

(2) When flying forward, the flapping rotor will have a large unbalanced moment due to the asymmetry of the incoming flow velocity during the forward and backward stages of the wing during the forward flight. After the introduction of the small rotor, the fast forward flight movement will bring about the high-speed rotation of the small rotor, and the small rotor will also have an unbalanced moment due to the force asymmetry between the forward and backward stages when the small rotor is flying forward. However, since the flapping rotor and the small rotor rotate in the opposite direction, the unbalanced moment of the two is just opposite, so the existence of the small rotor will weaken the existence of the unbalanced moment and reduce the difficulty of the control system design.

(3) Although the flapping rotor is passive in its rotation, there is still a frictional moment between it and the components of the transmission mechanism. In order to achieve stable control of the fuselage, it is necessary to overcome the frictional moment of the mechanism during control. The existence of the counter-rotating motion of the small rotor will introduce a reverse frictional moment, which will offset the frictional moment of the flapping rotor to a certain extent, and will also reduce the difficulty of the control system design.

The advantages of the present invention are:

(1) A kind of flapping wing and rotor composite micro-aircraft of the present invention reduces the load and power consumption of each wing, and the small rotor can supplement the lift generation without providing additional power, which reduces the output power of the motor.

(2) A flapping wing and rotor composite micro-aircraft of the present invention alleviates the unbalanced moment and small inter-mechanism friction moment when the traditional flapping rotor flies forward, and reduces the difficulty of control system design.

Description of drawings

Fig. 1 is the overall schematic diagram of a kind of flapping wing and rotor composite micro-aircraft of the present invention;

Fig. 2 is the flapping rotor schematic diagram of a kind of flapping wing and rotor composite micro-aircraft of the present invention;

Fig. 3 is a schematic diagram of the base of a flapping wing and rotor combined micro-aircraft of the present invention;

Fig. 4 is a schematic diagram of a transmission base of a flapping-wing and rotor composite micro-aircraft of the present invention;

Fig. 5 is a schematic diagram of a micro-motor of a flapping-wing and rotor composite micro-aircraft of the present invention;

In the picture:

1-flapping rotor 2-small rotor 3-base

4-Transmission device 5-Micro motor

101-Main Beam 102-Short Beam 103-Slanted Beam

104-foil 401-main shaft gear 402-big gear

403-Drive connecting rod 404-Inner rod 405-Rotor bracket

406-Large support 407-Large bearing 408-Small support

409-small bearing 410-wing connecting rod 411-rocker arm

Detailed ways

In order to understand the above-mentioned purpose, features and advantages of the present invention more clearly, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described here. Therefore, the protection scope of the present invention is not limited by the specific details disclosed below. EXAMPLE LIMITATIONS. The present invention will be further described in detail with reference to the accompanying drawings and embodiments.

Fig. 1 is the overall schematic diagram of a flapping wing and rotor combined micro-aircraft of the present invention, including a flapping rotor 1, a small rotor 2, a base 3, a transmission device 4, and a micromotor 5.

Fig. 2 shows an exemplary embodiment of the flapping rotor 1, the one main beam 101 and the two auxiliary beams 102, 103 are made of carbon fiber rods, and the wing membrane 104 is made of polyethylene film. During the initial installation, when the main beams of the flapping rotor 1 and the small rotor 2 are located in the horizontal plane, the angle between the flapping rotor 1 and the horizontal plane is designed to be between 10° and 15°, and the cylinder at the root of the main beam 101 is fixedly installed on the transmission In the reserved hole of the rocker arm 411 of the device 4. As shown in FIG. 1 , a pair of flapping rotors 1 are arranged anti-symmetrically with respect to the rotation axis.

An exemplary embodiment of the small rotor 2 is structurally the same as the flapping rotor 1, and also includes a main beam, two auxiliary beams and a membrane, and only the span length of the wing is 1/3-1/2 of the span of the flapping rotor 1 , the aspect ratio of the wing is between 5-7, the installation direction of the small rotor in the horizontal plane is opposite to that of the flapping rotor 1, and the bottom end of the main beam of the small rotor is bonded to the extended end of the rotor bracket 405 of the actuator rotating assembly.

Fig. 3 shows an exemplary embodiment of the base 3, which is integrally made of resin material or polylactic acid material through 3D printing. The base 3 has a symmetrical structure, a cylindrical cavity is reserved in the center of the upper surface, and a gear rack is arranged behind the cavity to support the large gear 402 . A space is reserved at the rear side of the gear rack for positioning the main shaft gear 401 . Thereafter, a sleeve is arranged in the vertical direction, and a central hole and a side groove are respectively opened for limiting the inner rod 404 .

Fig. 4 shows an exemplary embodiment of transmission device 4, including main shaft gear 401, speed reducer (big gear 402), oscillation assembly (transmission link 403, inner rod 404), flapping assembly (wing link 410a and 410b, rocker arms 411a and 411b), rotating assembly (rotor bracket 405, large support 406, large bearing 407, small support 408, small bearing 409). The inner rod 404 is made of light carbon fiber rod, the large bearing 407 and the small bearing 409 are made of light metal bearings, and the rest of the parts are integrally made of resin material or polylactic acid material through 3D printing. The main shaft gear 401 and the bull gear 402 mesh in the same plane and are perpendicular to the bottom surface of the base 3 . One end of the transmission connecting rod 403 is connected with the eccentric hole of the bull gear 402 with a rivet, and the other end is connected with the inner rod 404 through the groove of the sleeve side wall of the base 3 through the rivet. The inner rod 404 is placed in the sleeve of the base 3 and can slide vertically in the sleeve. The rotor bracket 405 is installed above the top of the sleeve of the base 3, leaving a certain gap with the upper end surface of the sleeve, and the inner rod 404 is inserted into the middle opening. The large support 406 is installed above the rotor support 405, leaving a certain gap with the upper end surface of the rotor support, and is hinged with the wing connecting rod 410, and the large bearing 407 is installed in the reserved hole of the large support 406. The small support 408 is mounted on the top of the inner rod 404 and hinged with the rocker arm 411 , and the small bearing 409 is installed in the reserved hole of the small support 408 . The wing link 410 is hinged to the rocker arm 411 . The function of the transmission device 4 is to convert the high-speed circular motion output by the motor into the up and down motion of the oscillating component through the reducer, drive the flapping component, and drive the flapping rotor 1 to perform a reciprocating flapping motion, and the flapping rotor 1 generates After the thrust moment, it starts to rotate around the rotating assembly.

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

In conjunction with Fig. 1-Fig. 5, the working process of a kind of flapping wing and rotor composite micro-aircraft of the present invention is illustrated. After the aircraft is powered, the micro-motor 5 outputs high-speed circular motion, which is decelerated by the transmission device 4 and converted into the reciprocating flapping motion of the flapping rotor 1 to generate a couple moment that drives the flapping rotor 1 to rotate, and the flapping rotor 1 starts to rotate until the rotation is stable, generating lift. When hovering, the small rotor 2 is passively rotated reversely by the wake airflow of the flapping rotor 1; when flying forward, the small rotor 2 is passively rotated reversely by the wake airflow of the flapping rotor 1 and the incoming flow of the forward flight.

Although the present invention has been described in detail with general descriptions and specific examples above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims (5)

1. A composite miniature aircraft with flapping wings and rotor wings is characterized by comprising a base, a transmission device, a miniature motor, flapping rotor wings and small rotor wings;

the flapping rotor wings and the small rotor wings are both a pair, and the flapping rotor wings are arranged at the tail end of the transmission device and can flap and rotate together with the transmission device;

the small rotor wing is of a light film structure, is coaxial with the flapping rotor wing, and is horizontally arranged below the flapping rotor wing in a rotating plane, and only performs rotating motion; the horizontal installation direction of the small rotor wing is opposite to that of the flapping rotor wing so as to realize reverse rotation;

the transmission device comprises a main shaft gear, a speed reducer and an executing mechanism; the main shaft gear is fixed on the output shaft of the miniature motor and meshed with the speed reducer to drive the high-speed rotary motion output by the motor to reduce the speed; the actuating mechanism comprises an oscillating assembly, a flapping assembly and a rotating assembly; the speed reducer is connected with the executing mechanism oscillating assembly, 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 flapping rotor wing to perform reciprocating flapping motion; the flapping rotor starts to rotate around the rotating assembly after generating pushing moment through flapping motion, and the small rotor rotates around the rotating assembly under the action of wake airflow and forward flying flow of the flapping rotor, but the rotating direction is opposite to that of the flapping rotor.

2. A composite flapping-rotor microminiature aircraft according to claim 1, wherein the small rotor span is 1/2-1/3 of the flapping wing span to ensure that the small rotor has a small moment of inertia for rapid rotation to generate lift.

3. A composite flapping-rotor microminiature aircraft according to claim 1, wherein the aspect ratio of the small rotor is 5-7 to ensure high aerodynamic efficiency of the small rotor.

4. A composite flapping-rotor microminiature aircraft according to claim 1, wherein the distance between the plane of rotation of the small rotor and the plane of rotation of the flapping rotor is in the range of 0.5 to 0.75 times the length of the flapping wing span.

5. A composite flapping-rotor microminiature aircraft according to claim 1, wherein the rotary assembly of the actuator is adapted to effect counter-rotation of the flapping rotor and the mini rotor about the same axis of rotation at different speeds.

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