Mechanical flapping-wing aircraft imitating insect wings with variable flapping amplitudes

Abstract

The present invention discloses a mechanical flapping-wing aircraft with variable flapping amplitude, mimicking the wings of an insect. The aircraft comprises a fuselage frame, a wing assembly with forewings and hindwings, a fuselage muscle assembly located within the fuselage frame and connected to the wing assembly for driving the flapping of the forewings and hindwings, a forewing muscle assembly connected to the wing assembly for varying the flapping amplitude of the forewings, a hindwing muscle assembly connected to the wing assembly for varying the flapping amplitude of the hindwings, and a head power assembly located within the fuselage frame and connected to the fuselage muscle assembly for generating power to the fuselage muscle assembly. The invention can change the flapping phase, amplitude, and frequency of the forewings and hindwings to achieve longitudinal and lateral attitude control of the aircraft, addressing the problem of flapping-wing aircraft's lack of maneuverability and difficulty in hovering.

Description

Technical Field

[0001] The present invention relates to an aircraft, and particularly to a mechanical flapping-wing aircraft imitating insect wings with variable flapping amplitudes. Background Art

[0002] In the field of micro unmanned aerial vehicles, due to the unique aerodynamic mechanism in the low Reynolds number environment, flapping-wing aircraft have unique advantages compared with conventional fixed-wing aircraft and rotorcraft. Compared with fixed-wing aircraft, flapping-wing aircraft have higher maneuverability and excellent hovering ability, and can take off and land in narrow environments (such as indoors, jungles, etc.) and perform complex tasks; compared with rotorcraft, flapping-wing aircraft have the advantages of low aerodynamic noise and high aerodynamic efficiency; therefore, they have broad application prospects in the field of micro aircraft.

[0003] For the driving methods of flapping-wing aircraft, they can be divided into piezoelectric and mechanical types. Piezoelectric driving has a high frequency and a simple mechanism, but due to energy limitations, it is difficult to fly relying on independent energy sources, and most remain in the laboratory stage; mechanical driving has a complex structure and is difficult to miniaturize, but due to its simple energy requirements, it is widely used in micro flapping-wing aircraft with independent flight capabilities.

[0004] Traditional flapping-wing aircraft follow the control idea of fixed-wing aircraft and use the deflection of the tail fin rudder surface to achieve the attitude control of the aircraft, while natural flying insects can achieve their own attitude control by adjusting the flapping parameters of their wings and have higher flight maneuverability.

[0005] Therefore, it is urgent to solve the above problems. Summary of the Invention

[0006] Object of the Invention: The object of the present invention is to provide a mechanical flapping-wing aircraft imitating insect wings with variable flapping amplitudes, which changes the flapping amplitudes of the front and rear wings to solve the problems of insufficient maneuverability and difficulty in hovering of flapping-wing aircraft.

[0007] Technical Solution: To achieve the above object, the present invention discloses a mechanical flapping-wing aircraft imitating insect wings with variable flapping amplitudes, including a fuselage frame, a wing assembly having front wings and rear wings, a fuselage muscle assembly located inside the fuselage frame and connected to the wing assembly for driving the front and rear wings to flap, a front wing muscle assembly connected to the wing assembly for changing the flapping amplitude of the front wings, a rear wing muscle assembly connected to the wing assembly for changing the flapping amplitude of the rear wings, and a head power assembly located at the head of the fuselage frame and connected to the fuselage muscle assembly for generating power to the fuselage muscle assembly.

[0008] Among them, the fuselage muscle assembly includes a pair of front wing root rotating shafts connected to the front wings, a front cam thimble hinged to the pair of front wing root rotating shafts and forming a rotating pair, a front bearing fixed to the lower side of the front cam thimble, a front wing cam forming a rolling pair with the front bearing, a pair of rear wing root rotating shafts connected to the rear wings, a rear cam thimble hinged to the pair of rear wing root rotating shafts, a pair of rear bearings fixed to the lower side of the rear cam thimble, and a rear wing cam forming a rolling pair with each rear bearing. The head power assembly outputs power to drive the rotation of the front wing cam and the rear wing cam, respectively driving the front cam thimble and the rear cam thimble to reciprocate up and down. The axis of the front wing root rotating shaft reciprocates with the front cam thimble, and the axis of the rear wing root rotating shaft reciprocates with the rear cam thimble, generating the power for the wing flapping.

[0009] Preferably, a front slider is provided on the front cam thimble, and the front slider forms a sliding pair with the front sliding groove on the fuselage frame. A rear slider is provided on the rear cam thimble, and the rear slider forms a sliding pair with the rear sliding groove on the fuselage frame. The lower side of the front cam thimble is connected to the fuselage frame by a spring, which pulls it back during the downward stroke of the front wing cam to maintain the contact between the front cam thimble and the front wing cam. The rotation of the front wing cam and the pulling force of the spring cause the front cam thimble fixed in the front sliding groove of the fuselage frame to reciprocate. The lower side of the rear cam thimble is connected to the fuselage frame by a spring, which pulls it back during the downward stroke of the rear wing cam to maintain the contact between the rear cam thimble and the rear wing cam. The rotation of the rear wing cam and the pulling force of the spring cause the rear cam thimble fixed in the rear sliding groove of the fuselage frame to reciprocate.

[0010] Furthermore, the front wing muscle assembly includes a front wing servo fixed to the fuselage frame, a small gear connected to the output shaft of the front wing servo, a front wing bracket having a rack meshing with the small gear, and ball bearing joints located at both ends of the front wing bracket. The front wing bracket is provided with a front horizontal sliding groove, and the front horizontal sliding groove forms a sliding pair with the front wing slider on the fuselage frame. When the front wing servo drives the small gear to rotate, the front wing bracket is driven to slide left and right through the rack, changing the relative position of the ball bearing joint and the reciprocating motion plane of the front wing root rotating shaft. The front wing bracket moves from the leftmost position to the neutral position and then to the rightmost position, changing the flapping amplitude of the left and right wings of the front wing.

[0011] Further, the ball bearing joint supports at the middle of the wing root of the front wing, providing a fulcrum for the wing root. The wing root can slide and rotate at the ball bearing joint, forming a cylindrical pair. The up and down undulation of the front wing root rotating shaft will be converted into a large swing of the wing through the fulcrum.

[0012] Preferably, the hind wing muscle assembly includes a hind wing servo fixed to the fuselage skeleton, a double crank connected to the output shaft of the hind wing servo, two symmetrical hind wing brackets connected to the double crank, and a spherical bearing joint fixed to the hind wing brackets. The hind wing brackets are provided with rear transverse chutes, and the rear transverse chutes are in contact with the hind wing sliders on the fuselage skeleton to form a sliding pair. When the hind wing servo drives the double crank to rotate, the left and right hind wing brackets will simultaneously fold inwards or expand outwards, while reducing or increasing the relative position of the left and right spherical bearing joints with respect to the reciprocating motion plane of the hind wing root rotating shaft, thereby changing the flapping amplitude of the hind wing.

[0013] Furthermore, the spherical bearing joint supports the middle part of the hind wing root, providing a fulcrum for the hind wing root. The hind wing root can slide and rotate at the spherical bearing joint, forming a cylindrical pair. The up and down fluctuations of the hind wing root rotating shaft will be converted into large swings of the wing through the fulcrum.

[0014] Preferably, the root ends of the fore wings and hind wings are both fan-shaped connecting shafts, and both the fore wing root rotating shaft and the hind wing root rotating shaft have fan-shaped connecting holes. The root of the fore wing is inserted into the fore wing root rotating shaft, and the root of the fore wing can be limited in rotation in the fore wing root rotating shaft. The root of the hind wing is inserted into the hind wing root rotating shaft, and the root of the hind wing can be limited in rotation in the hind wing root rotating shaft.

[0015] Furthermore, the head power assembly includes brushless motors installed on the left and right sides of the head of the fuselage skeleton and a three-stage reduction gear set connected to the output shaft of each brushless motor. The gear shafts of the three-stage reduction gear set are fixed to the fuselage skeleton through bearings; the last-stage gear of the three-stage reduction gear set is coaxially arranged with the fore wing cam, and the synchronizing gear meshing with the last-stage gear at the same level is coaxially arranged with the hind wing cam. The fore wing cam and the hind wing cam are staggered in the radial direction. When the brushless motor is started, the torque is transmitted to the fore wing cam and the hind wing cam through the three-stage reduction gear set, driving the fore wing cam and the hind wing cam to rotate.

[0016] Furthermore, both the fore wings and hind wings of the wing assembly include pterostigma for reducing high-frequency vibrations, wing membranes, wing veins, and wing roots for bearing aerodynamic loads.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: The present invention can change the flapping phase, flapping amplitude, and flapping frequency of the front and rear wings to achieve longitudinal and lateral attitude control of the aircraft, solve the problem of insufficient maneuverability of the flapping-wing aircraft and difficulty in hovering; the servo motors provided for the front pair of wings of the present invention can drive the mechanism to increase the flapping amplitude on one side while decreasing the flapping amplitude on the other side, generating a rolling moment; the servo motors provided for the rear pair of wings can drive the mechanism while increasing or decreasing the flapping amplitudes on both sides, thereby generating a pitching moment; the wings can also rotate around the wing root axis while flapping up and down, increasing the aerodynamic efficiency; the present invention realizes the reciprocating movement of the wing roots through the cam structure in the fuselage muscle assembly, reducing the inertial force generated during the movement of the mechanism; through the fan-shaped connection structure of the wing root rotating shaft, the limited rotation of the wings during flapping is realized, improving the aerodynamic efficiency of the wing flapping; this aircraft does not require an additional tail wing to control the flight attitude, has a compact structure, simple operation, and a realistic bionic shape. Description of the Drawings

[0018] Figure 1 is the front view of the present invention;

[0019] Figure 2 is the side view of the present invention;

[0020] Figure 3 is the top view of the present invention;

[0021] Figure 4 is the schematic diagram of the internal structure of the present invention;

[0022] Figure 5 is the schematic diagram of the structure of the head power assembly in the present invention;

[0023] Figure 6 is the schematic diagram of the structures of the front wing cam and the rear wing cam in the present invention;

[0024] Figure 7 is the connection schematic diagram of the wing root part in the present invention;

[0025] Figure 8 is the movement schematic diagram of the wing root part in the present invention;

[0026] Figure 9 is the schematic diagram of the structure of the wing assembly in the present invention;

[0027] Figure 10 is the partial schematic diagram of the fuselage skeleton in the present invention;

[0028] Figure 11 is the schematic diagram of the wing flapping motion mechanism in the present invention;

[0029] Figure 12 is the schematic diagram of the front wing support moving mechanism in the present invention;

[0030] Figure 13 Schematic diagram of the mechanism for controlling the change in the flapping amplitude of the front wings of the present invention;

[0031] Figure 14 Schematic diagram of the mechanism for moving the rear wing support of the present invention;

[0032] Figure 15 Schematic diagram of the mechanism for controlling the change in the flapping amplitude of the rear wings of the present invention;

[0033] Figure 16 Schematic diagram of the connection between the front cam ejector pin and the fuselage skeleton at the initial stage in the present invention;

[0034] Figure 17 Schematic diagram of the connection between the front cam ejector pin and the fuselage skeleton when stretched in the present invention;

[0035] Figure 18 Schematic diagram of the connection between the rear cam ejector pin and the fuselage skeleton at the initial stage in the present invention;

[0036] Figure 19 Schematic diagram of the connection between the rear cam ejector pin and the fuselage skeleton when stretched in the present invention;

[0037] Figure 20 Schematic diagram of the structure of the three - stage reduction gear set in the present invention;

[0038] Figure 21 Schematic diagram of the structures of the front wing muscle assembly and the rear wing muscle assembly in the present invention;

[0039] Figure 22 Schematic diagram of the structure of the fuselage skeleton in the present invention. Detailed implementation manners

[0040] The technical solutions of the present invention will be further described below with reference to the accompanying drawings.

[0041] As Figure 1 、 Figure 2 、 Figure 3 and Figure 4As shown in the figure, a mechanical flapping-wing aircraft with variable flapping amplitudes imitating insect wings of the present invention includes a fuselage frame 9, wing assemblies, a fuselage muscle assembly, a front-wing muscle assembly, a rear-wing muscle assembly, and a head power assembly. The fuselage muscle assembly is located inside the fuselage frame and is used to drive the front and rear wings to flap. The front-wing muscle assembly is connected to the wing assemblies and is used to change the flapping amplitude of the front wings. The rear-wing muscle assembly is connected to the wing assemblies and is used to change the flapping amplitude of the rear wings. The head power assembly is located at the head of the fuselage frame and is connected to the fuselage muscle assembly and is used to generate power to the fuselage muscle assembly. The present invention controls the rotation speed of the brushless motor of the head power assembly to change the flapping phase and flapping frequency of the front and rear wings, and uses the front-wing muscle assembly and the rear-wing muscle assembly to change the flapping amplitude to achieve the longitudinal and lateral attitude control of the aircraft.

[0042] As Figure 5 shown, the head power assembly includes a brushless motor 18 and a three-stage reduction gear set 19. The 1100KV brushless motor 18 is installed on the left and right sides of the head of the fuselage frame, and the output shaft of each brushless motor is connected to a corresponding set of three-stage reduction gear sets 19. As Figure 20 shown, the gear shafts of the three-stage reduction gear set are fixed on the fuselage frame through bearings; the last-stage gear of the three-stage reduction gear set 19 is coaxially arranged with the front-wing cam 5, and the synchronous gear meshing with the last-stage gear at the same level is coaxially arranged with the rear-wing cam 10. Due to space limitations, when the rotation phase of the front-wing cam and the rear-wing cam is between 90° and 270°, there will be mutual interference of the mechanism. The rear-wing cam is divided into two. When the phase difference between the rotation of the front-wing cam and the rear-wing cam is within the interference range, the front-wing cam and the rear-wing cam are staggered radially. The brushless motor 18 starts, and transmits the torque to the front-wing cam 5 and the rear-wing cam 10 through the three-stage reduction gear set 18, and drives the front-wing cam and the rear-wing cam to rotate to provide the kinetic energy of the movement of the fuselage muscle assembly. The three-stage reduction gear set is composed of two standard involute gears with a module of 0.5. The number of teeth of the small gear is 10, the number of teeth of the large gear is 40, and the total reduction ratio is 64:1. The shafts of the reduction gears are fixed on the fuselage frame part through bearings.

[0043] As Figure 9As shown, the wing assembly has a pair of front wings 1 and a pair of rear wings 6. Both the front wings 1 and the rear wings 6 of the wing assembly include wing nodes 101, wing membranes 102, wing veins 103, and wing roots 104. The wing membrane 102 bears the aerodynamic load, similar to the skin of an airplane. The wing node 101 is filled with solder to change the mass distribution of the wing to reduce high-frequency vibration. The wing assembly is mainly responsible for generating aerodynamic force. The wing vein 103 is the main framework of the wing, transmitting the force of the wing membrane 102 to the wing root 104, similar to the wing beam and wing rib of an airplane. The wing node 101 is located outside the wing vein and is used to adjust the mass distribution of the wing, reducing the vibration of the wing during flapping, similar to the counterweight of an airplane. The wing root 104 connects the wing vein 103 and the wing root rotating shaft. The outer side is fixedly connected to the wing vein 103. The middle part is in contact with the spherical bearing joint to form a cylindrical pair, and the inner part is in contact with the wing root rotating shaft to form a rotating pair. The axial degree of freedom is restricted by the mortise buckle on the wing root rotating shaft to prevent it from slipping. As Figure 5 shown, through the limit design of the inner part of the wing root rotating shaft cooperating with the wing root, the wing root obtains a degree of freedom of rotation and can freely rotate within a range of 90°.

[0044] As Figure 6 , Figure 7 and Figure 8 shown, the fuselage muscle assembly includes a pair of front wing root rotating shafts 2, front cam push rods 3, front bearings 401, front wing cams 5, rear wing root rotating shafts 7, rear cam push rods 8, rear bearings 402, and rear wing cams 10. A pair of front wing root rotating shafts 2 are connected to the front wings 1. The wing root ends of the front wings 1 are all fan-shaped connecting shafts. The front wing root rotating shafts 2 have fan-shaped connecting holes. The wing roots of the front wings are inserted into the front wing root rotating shafts, and the wing roots of the front wings can be rotationally limited in the front wing root rotating shafts. The front cam push rod 3 is hinged to a pair of front wing root rotating shafts 2 and forms a rotating pair. The front bearing 401 is fixed to the lower side of the front cam push rod 3. The front wing cam 5 forms a rolling pair with the front bearing 401. A pair of rear wing root rotating shafts 7 are connected to the rear wings 6. The wing root ends of the rear wings 6 are fan-shaped connecting shafts. The rear wing root rotating shafts 7 have fan-shaped connecting holes. The wing roots of the rear wings are inserted into the rear wing root rotating shafts, and the wing roots of the rear wings can be rotationally limited in the rear wing root rotating shafts. The rear cam push rod 8 is hinged to a pair of rear wing root rotating shafts. A pair of rear bearings 402 are fixed to the lower side of the rear cam push rod. Two rear wing cams 10 form rolling pairs with the two rear bearings 402 one by one. The head power assembly outputs power to drive the front wing cam 5 and the rear wing cam 10 to rotate, respectively driving the front cam push rod 3 and the rear cam push rod 8 to reciprocate up and down. The axis of the front wing root rotating shaft 2 reciprocates with the front cam push rod 3, and the axis of the rear wing root rotating shaft 7 reciprocates with the rear cam push rod 8, generating the power for wing flapping.

[0045] As Figure 16 and Figure 17As shown in the figure, a front slider 301 is provided on the front cam ejector pin 3. The front slider 301 and the front chute 901 on the fuselage frame 9 form a sliding pair. A rear slider 801 is provided on the rear cam ejector pin 8. The rear slider 801 and the rear chute 902 on the fuselage frame form a sliding pair. The lower side of the front cam ejector pin 3 is connected to the fuselage frame 9 by a spring 20, and it is pulled back during the downward stroke of the front wing cam 5 to maintain the contact between the front cam ejector pin 3 and the front wing cam 5. The rotation of the front wing cam 5 and the pulling force of the spring cause the front cam ejector pin 3 fixed in the front chute 901 of the fuselage frame 9 to perform reciprocating motion. As Figure 18 and Figure 19 shown in the figure, the lower side of the rear cam ejector pin 8 is connected to the fuselage frame 9 by a spring 20, and it is pulled back during the downward stroke of the rear wing cam 10 to maintain the contact between the rear cam ejector pin 8 and the rear wing cam 10. The rotation of the rear wing cam 10 and the pulling force of the spring cause the rear cam ejector pin 8 fixed in the rear chute 902 of the fuselage frame 9 to perform reciprocating motion.

[0046] Due to the limitation of the mechanism space, the spring arrangements of the front cam ejector pin and the rear cam ejector pin are different. As Figure 16 and Figure 17 shown in the figure, the spring of the front cam ejector pin is arranged horizontally along the fuselage axis. As Figure 18 and Figure 19 shown in the figure, the spring of the rear cam ejector pin is arranged longitudinally along the fuselage axis. The spring is always in a stretched state, only with different stretching lengths.

[0047] As Figure 21 shown in the figure, the front wing muscle assembly includes a front wing servo 11, a pinion 12, a front wing bracket 13, and a ball bearing joint 14. The front wing servo 11 is fixed to the fuselage frame. The pinion 12 is connected to the output shaft of the front wing servo 11. The front wing bracket 13 has a rack meshing with the pinion 12. The ball bearing joints 14 are located at both ends of the front wing bracket. The front wing bracket 13 is provided with a front horizontal chute 1301. The front horizontal chute 1301 contacts with the front wing slider 903 on the fuselage frame 9 to form a sliding pair. When the front wing servo 11 drives the pinion 12 to rotate, the front wing bracket 13 is driven to slide left and right through the rack, changing the relative position of the ball bearing joint 14 and the reciprocating motion plane of the front wing root rotating shaft 2. The front wing bracket 13 moves from the leftmost position to the neutral position and then to the rightmost position, changing the flapping amplitude of the left and right wings of the front wing, so as to generate an asymmetric aerodynamic force on both sides of the fuselage to achieve the effect of lateral attitude control. The ball bearing joint 14 supports the middle part of the wing root of the front wing 1, providing a fulcrum for the wing root. The wing root can slide and rotate at the ball bearing joint 14 to form a cylindrical pair. The up and down undulation of the front wing root rotating shaft 2 will be converted into a large swing of the wing through the fulcrum. As Figure 11 shown in the figure, the process of the front wing root rotating shaft translating from the highest point to the lowest point. As Figure 12As shown, the front wing support moves from the leftmost position to the neutral position and then to the rightmost position, changing the flapping amplitudes of the left and right wings, as Figure 13 shown, thereby generating asymmetric aerodynamic forces on both sides of the fuselage to achieve the effect of lateral attitude control.

[0048] As Figure 14 and Figure 15 shown, the rear wing muscle assembly includes a rear wing servo 15, a double crank 16, a rear wing support 17, and a ball bearing joint 14. The double crank includes a first crank with its middle part connected to the output shaft of the rear wing servo, connecting rods symmetrically arranged at both ends of the first crank, and the other ends of the two connecting rods are respectively connected to the two rear wing supports in a one-to-one correspondence. The rear wing servo 15 is fixed to the fuselage skeleton, the double crank 16 is connected to the output shaft of the rear wing servo, the left and right symmetric rear wing supports 17 are connected to the double crank, the ball bearing joint 14 is fixed to the rear wing support 17, and the rear wing support 17 is provided with a rear lateral sliding groove 1701. The rear lateral sliding groove 1701 contacts the rear wing slider 904 on the fuselage skeleton to form a sliding pair. When the rear wing servo 15 drives the double crank 16 to rotate, the left and right rear wing supports 17 will simultaneously move inwards or outwards, simultaneously reducing or increasing the relative position of the left and right ball bearing joints 14 with respect to the reciprocating motion plane of the rear wing root rotating shaft 7, changing the flapping amplitude of the rear wing, thereby changing the pitching moment of the aircraft to achieve the effect of longitudinal attitude control. The ball bearing joint 14 supports the middle part of the root of the rear wing 6, providing a fulcrum for the wing root. The wing root can slide and rotate at the ball bearing joint 14 to form a cylindrical pair. The up and down fluctuations of the rear wing root rotating shaft 7 will be converted into large swings of the wing through the fulcrum.

[0049] As Figure 10 and Figure 22 shown, the fuselage skeleton 9 includes an inner skeleton 905, an outer skeleton 906, and a tail 907 for balancing the center of gravity and moment of inertia. The inner skeleton 905 and the outer skeleton 906 are connected to each other by bolts for convenient assembly. The inner skeleton 905 is provided with a front sliding groove 901, a rear sliding groove 902, a servo card slot 908 for placing the front wing servo 11, and a motor card slot 909 for placing the brushless motor 18; the outer skeleton 906 is provided with a front wing slider 903, a rear wing slider 904, and a bearing card slot 910 for placing the gears in the three-stage reduction gear set. The front sliding groove 901 and the front slider 301 of the front cam ejector pin 3 form a sliding pair to restrict the reciprocating motion trajectory of the front cam ejector pin. The rear sliding groove 902 and the rear slider 801 of the rear cam ejector pin 8 form a sliding pair to restrict the reciprocating motion trajectory of the rear cam ejector pin. The servo card slot 908, the bearing card slot 910, and the motor card slot 909 are responsible for placing the corresponding components. The front wing slider 903 and the rear wing slider 904 form sliding pairs with the sliding grooves on the front wing support 13 and the rear wing support 17 to restrict the translation of the support.

Claims

1. A mechanical flapping-wing aircraft with variable flapping amplitude imitating insect wings, characterized in that: It includes a fuselage skeleton (9), a wing assembly with a front wing (1) and a rear wing (6), a fuselage muscle assembly located inside the fuselage skeleton and connected to the wing assembly for driving the flapping of the front and rear wings, a front wing muscle assembly connected to the wing assembly for changing the flapping amplitude of the front wing, a rear wing muscle assembly connected to the wing assembly for changing the flapping amplitude of the rear wing, and a head power assembly located at the head of the fuselage skeleton and connected to the fuselage muscle assembly for generating power to the fuselage muscle assembly; the fuselage muscle assembly includes a pair of front wing root rotating shafts (2) connected to the front wing (1), a front cam ejector pin (3) hinged to the pair of front wing root rotating shafts to form a rotating pair, a front bearing (401) fixed to the lower side of the front cam ejector pin, a front wing cam (5) forming a rolling pair with the front bearing, a pair of rear wing root rotating shafts (7) connected to the rear wing (6), a rear cam ejector pin (8) hinged to the pair of rear wing root rotating shafts, a pair of rear bearings (402) fixed to the lower side of the rear cam ejector pin, and a rear wing cam (10) forming a rolling pair with each rear bearing. The head power assembly outputs power to drive the rotation of the front wing cam (5) and the rear wing cam (10), respectively driving the up-and-down reciprocating motion of the front cam ejector pin (3) and the rear cam ejector pin (8). The axis of the front wing root rotating shaft (2) reciprocates with the front cam ejector pin (3), and the axis of the rear wing root rotating shaft (7) reciprocates with the rear cam ejector pin (8) to generate wing flapping power. The rear wing muscle assembly includes a rear wing servo (15) fixed to the fuselage skeleton, a double crank (16) connected to the output shaft of the rear wing servo, two symmetric rear wing brackets (17) connected to the double crank, and a spherical bearing joint (14) fixed to the rear wing bracket. The rear wing bracket (17) is provided with a rear transverse chute (1701), and the rear transverse chute (1701) contacts the rear wing slider (904) on the fuselage skeleton to form a sliding pair. When the rear wing servo (15) drives the double crank (16) to rotate, the left and right rear wing brackets (17) will simultaneously converge towards the middle or expand towards both sides, simultaneously reducing or increasing the relative position of the left and right spherical bearing joints (14) with respect to the reciprocating motion plane of the rear wing root rotating shaft (7), thereby changing the flapping amplitude of the rear wing. The root ends of the front wings (1) and the rear wings (6) are both fan-shaped connecting shafts. The front wing root rotating shafts (2) and the rear wing root rotating shafts (7) are both provided with fan-shaped connecting holes. The root of the front wing is inserted into the front wing root rotating shaft, and the root of the front wing can be rotationally limited in the front wing root rotating shaft. The root of the rear wing is inserted into the rear wing root rotating shaft, and the root of the rear wing can be rotationally limited in the rear wing root rotating shaft. The head power assembly includes brushless motors (18) installed on the left and right sides of the head of the fuselage frame, and three-stage reduction gear sets (19) connected to the output shafts of each brushless motor. The gear shafts of the three-stage reduction gear sets are fixed to the fuselage frame through bearings. The last-stage gear of the three-stage reduction gear set (19) is coaxially arranged with the front wing cam (5), and the synchronous gear meshing with the last-stage gear at the same level is coaxially arranged with the rear wing cam (10). The front wing cam and the rear wing cam are staggered in the radial direction. When the brushless motor (18) is started, torque is transmitted to the front wing cam (5) and the rear wing cam (10) through the three-stage reduction gear set (19), and the front wing cam and the rear wing cam are driven to rotate.

2. The mechanical flapping-wing aircraft with variable flapping amplitude of imitating insect double wings according to claim 1, wherein: The front cam ejector pin (3) is provided with a front slider (301), and the front slider (301) and the front chute (901) on the fuselage frame (9) form a sliding pair. The rear cam ejector pin (8) is provided with a rear slider (801), and the rear slider (801) and the rear chute (902) on the fuselage frame form a sliding pair. The lower side of the front cam ejector pin (3) is connected to the fuselage frame (9) by a spring (20), and it is pulled back during the downward stroke of the front wing cam (5) to maintain the contact between the front cam ejector pin (3) and the front wing cam (5). The rotation of the front wing cam (5) and the pulling force of the spring cause the front cam ejector pin (3) fixed in the front chute (901) of the fuselage frame (9) to perform reciprocating motion. The lower side of the rear cam ejector pin (8) is connected to the fuselage frame (9) by a spring (20), and it is pulled back during the downward stroke of the rear wing cam (10) to maintain the contact between the rear cam ejector pin (8) and the rear wing cam (10). The rotation of the rear wing cam (10) and the pulling force of the spring cause the rear cam ejector pin (8) fixed in the rear chute (902) of the fuselage frame (9) to perform reciprocating motion.

3. The mechanical flapping-wing aircraft with variable flapping amplitude of imitating insect's double wings according to claim 1, characterized in that: The front wing muscle assembly includes a front wing servo (11) fixed to the fuselage frame, a small gear (12) connected to the output shaft of the front wing servo, a front wing bracket (13) having a rack meshing with the small gear, and ball bearing joints (14) located at both ends of the front wing bracket. The front wing bracket (13) is provided with a front transverse chute (1301), and the front transverse chute (1301) contacts the front wing slider (903) on the fuselage frame (9) to form a sliding pair. When the front wing servo (11) drives the small gear (12) to rotate, the front wing bracket (13) is driven to slide left and right through the rack, changing the relative position of the ball bearing joint (14) with respect to the reciprocating motion plane of the front wing root rotating shaft (2). The front wing bracket (13) moves from the leftmost position to the neutral position and then to the rightmost position, changing the flapping amplitude of the left and right wings of the front wing.

4. The mechanical flapping-wing aircraft with variable flapping amplitude of imitating insect's double wings according to claim 2, wherein: The ball bearing joint (14) is supported in the middle of the wing root of the front wing (1), providing a fulcrum for the wing root. The wing root can slide and rotate at the ball bearing joint (14), forming a cylindrical pair. The up and down undulation of the front wing root rotating shaft (2) will be converted into a large swing of the wing through the fulcrum.

5. The mechanical flapping-wing aircraft with variable flapping amplitude of imitating insect double wings according to claim 1, characterized in that: The ball bearing joint (14) is supported in the middle of the wing root of the rear wing (6), providing a fulcrum for the wing root. The wing root can slide and rotate at the ball bearing joint (14), forming a cylindrical pair. The up and down undulation of the rear wing root rotating shaft (7) will be converted into a large swing of the wing through the fulcrum.

6. The mechanical flapping-wing aircraft with variable flapping amplitude of imitating insect's double wings according to claim 1, wherein: Both the front wing (1) and the rear wing (6) of the wing assembly include pterostigma (101) for reducing high-frequency vibration, wing membrane (102) for bearing aerodynamic load, wing veins (103) and wing roots (104).

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