CN111547237A

CN111547237A - Ornithopter with two-degree-of-freedom motion

Info

Publication number: CN111547237A
Application number: CN202010375032.5A
Authority: CN
Inventors: 王姝歆; 熊凡; 陈国平; 金宝; 刘润
Original assignee: Nanjing University of Aeronautics and Astronautics
Current assignee: Nanjing University of Aeronautics and Astronautics
Priority date: 2020-05-06
Filing date: 2020-05-06
Publication date: 2020-08-18
Anticipated expiration: 2040-05-06
Also published as: CN111547237B

Abstract

The invention discloses a flapping-wing aircraft with two degrees of freedom, which comprises a rack, a motor and a gear reduction mechanism, wherein the rack is provided with a pair of flapping mechanisms and a pair of rotating mechanisms, the gear reduction mechanism is respectively connected with the motor and the flapping mechanisms, the side surface of the rack is symmetrically provided with a sliding chute, each rotating mechanism comprises a guide block, a guide rod and a spring, one end of each guide rod is fixedly connected with the corresponding guide block, the other end of each guide rod is connected with a bionic wing, the guide blocks can rotate along the semicircular inner wall of the corresponding sliding chute at the upper end and the lower end of the corresponding sliding chute and drive the bionic wings to rotate, the guide rods are provided with the springs and reset under the action of. The up-and-down motion of the guide block and the up-and-down flapping of the bionic wings form 180-degree opposite phase. The invention can realize the flapping amplitude of 100 degrees and the rotation amplitude of 90 degrees, and can better simulate the motion characteristic of the periodic large-amplitude flapping of the insect wings; the motion with two degrees of freedom is realized by using the pair of flapping mechanisms and the pair of rotating mechanisms, so that the problems of complexity and heaviness in the driving rotation of a multi-link or space mechanism can be reduced.

Description

Ornithopter with two-degree-of-freedom motion

Technical Field

The invention belongs to the field of aircrafts, and particularly relates to a flapping-wing aircraft with two degrees of freedom.

Background

The micro aircraft has three different flight modes: fixed wing, rotor and flapping wing. Compared with the conventional aircraft, the Reynolds number of the micro aircraft is very low and is about 10¹～10⁵In the meantime. In the Reynolds number range, natural flyers such as insects and birds do not fly in a fixed wing or rotor wing driving mode similar to mechanical flight, but the natural flyers fly autonomously by means of flapping wings, have extremely high maneuvering flexibility and consume little energy.

The micro flapping wing air vehicle, also known as a micro flapping wing machine, a micro flapping wing air vehicle, an insect-imitating flying robot and the like is designed by imitating the movement mechanism of natural insects, and is one of the focuses of the current research. The miniature flapping wing aircraft can integrate the lifting, hovering and propelling functions into a flapping wing system, can fly for a long distance by using very small energy, has stronger maneuverability, and can take off in situ or in a small field and hover in the air, thereby being more suitable for executing tasks under the long-time non-energy supplement and long-distance conditions, and further having wide application prospect in the military and civil fields.

Through the search and discovery of the prior art, two papers relate to the research of a two-degree-of-freedom flapping wing mechanism. The university of aerospace, journal of jiaming et al, beijing, 2006 (09): 1087 and 1090, in the paper "design and kinematic analysis of bionic flapping wing mechanism", a two-degree-of-freedom flapping wing mechanism is designed. The flapping and rotating motion is realized by adopting two groups of crank rocker mechanisms and differential gears which are connected in parallel. Raynaud et al, in mechanical design and manufacture, 2017 (06): 241-244, in the article "design and motion analysis of two-degree-of-freedom bionic flapping-wing flying robot", a two-degree-of-freedom flapping-wing mechanism is designed. The spatial RSSR mechanism and the crank-rocker mechanism are coupled to realize flapping and rotation, wherein the spatial RSSR mechanism realizes flapping motion, and the crank-rocker mechanism realizes torsion motion. The two designs are both complex and have small flapping wing motion amplitude, the existing flapping wing mechanism with one degree of freedom is too simple, and the flapping wing mechanisms with three degrees of freedom are too complex and heavy.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the defects in the prior art, the invention aims to provide the ornithopter capable of simulating the wings of insects, realizing 100-degree flapping and 90-degree rotation, simplifying a driving mechanism and realizing light-weight two-degree-of-freedom motion.

The technical scheme is as follows: the invention relates to a flapping-wing machine with two degrees of freedom, which comprises a machine frame, a motor and a gear reduction mechanism, wherein a pair of flapping mechanisms and a pair of rotating mechanisms are arranged on the machine frame, the gear reduction mechanism is respectively connected with the motor and the flapping mechanisms, sliding grooves are symmetrically arranged on the side surface of the machine frame, each rotating mechanism comprises a guide block, a guide rod and a spring, one end of each guide rod is fixedly connected with the corresponding guide block, the other end of each guide rod is connected with a bionic fin, the guide blocks can rotate along the semicircular inner walls of the sliding grooves at the upper end and the lower end of each sliding groove and drive the bionic fins to rotate, the springs are arranged on the guide rods and reset under the action. The up-and-down motion of the guide block and the up-and-down flapping of the bionic wings form 180-degree opposite phase.

The flapping mechanism comprises a connecting rod and a rocker which are hinged with each other, the rocker is connected with the guide rod through a first bump and a second bump, and a spring is arranged on the guide rod between the first bump and the second bump. The back of the frame is provided with a fixed rod which is respectively hinged with the first convex blocks at the two sides of the frame.

The motor comprises a gear and drives the gear to rotate. The gear reduction mechanism comprises a gear II, a gear III, a gear IV, a gear V and a gear VI, the gear II and the gear III are coaxial, the gear III is respectively meshed with the gear IV and the gear V, and the gear IV and the gear VI are meshed. One side of the rack is provided with a first gear and a second gear which are meshed with each other, and the other side of the rack is provided with a third gear, a fourth gear, a fifth gear and a sixth gear. And the fifth gear and the sixth gear are respectively hinged with the connecting rod. The diameters of the third gear and the fourth gear are the same. The diameters of the fifth gear and the sixth gear are the same.

The guide block is in a drop shape. The bionic wing is designed in a simulation mode on the basis of the wing shape of a natural insect cicada, the wing shape of the cicada is subjected to parametric design by adopting the MArLAB, and the bionic wing is subjected to modal analysis and deformation analysis by adopting the ANSYS.

The working principle is as follows: the first gear is driven by the motor, so that the rotating motion of the fifth gear and the sixth gear of the gear reduction mechanism is driven, and then the rotating motion is transmitted to the connecting rods on the left side and the right side of the rack, and the connecting rods rotate to drive the rocking rods and the bionic wings to flap, so that the flapping motion is realized. The guide block and the sliding groove form a cam mechanism, the guide block is used as a cam, the guide groove is used as a cam groove, the guide block rotates when moving between the guide grooves, meanwhile, the spring is extruded, and when the guide block reaches the semi-circular arcs at the upper end and the lower end of the guide groove in the working stroke, the guide block resets under the action of the torsion spring.

The flight method comprises the following steps:

1. a transmission stage: the motor is started, the motor shaft and the first gear are coaxially pivoted, the power of the motor is output through the motor shaft and drives the first gear to rotate, the second gear of the gear speed reducing mechanism is meshed with the first gear, therefore, the second gear rotates, the third gear and the second gear are concentric gears, the middle is connected with a transmission rod, the third gear rotates, the fourth gear rotates, the fifth gear is meshed with the third gear, the sixth gear is meshed with the fourth gear, the fifth gear and the sixth gear rotate, and the rotating speed is reduced, so that the torque is increased.

2. A flapping stage: when the gear six rotates, the connecting rod hinged on the gear six also moves along with the gear six, and the gear six plays a role of a crank at the moment. One end of each connecting rod is hinged with the fifth gear or the sixth gear, and the other end of each connecting rod is hinged with the rocker, so that the rocker starts to move. The rocker is rotatably connected with one end of the guide rod through the first projection and the second projection, and the other end of the guide rod is embedded in the sliding groove, so that the guide rod performs flapping. Meanwhile, the bionic fin is fixedly connected with the guide rod, so that the bionic fin also performs flapping motion.

3. And (3) a rotation stage: the up-and-down motion of the guide block and the up-and-down flapping of the bionic wings form 180-degree opposite phase. When the bionic wings reach the two extremes of the flapping stroke, the sliding grooves and the guide blocks start to work. The upper and lower movement of the guide block and the upper and lower flapping of the bionic wing are set to be opposite in phase, when the bionic wing flaps upwards, the guide block moves downwards, the protruding part of the guide block contacts the inner wall of a chute in the rack to force the guide block to rotate so as to drive the bionic wing to rotate to the vertical direction, the guide block is a part of the guide rod embedded into the chute, a spring is arranged on the part of the guide rod between the first lug and the second lug, one end of the spring is fixedly connected with the second lug, and the maximum movement distance of the spring is limited by a limiting block of the guide rod between the first lug and the second lug. The spring is in a compressed state and forces the guide block to descend to the bottom of the chute in the frame. When the bionic wing reaches the bottom of the sliding groove of the rack, the spring is released and the guide block is reset due to the semicircular arc spaces at the upper end and the lower end of the sliding groove in the rack, and the bionic wing returns to the initial state. When the bionic wing is beaten down, the guide block goes up.

Has the advantages that: compared with the prior art, the invention has the following remarkable characteristics:

1. the flapping amplitude of 100 degrees and the rotation amplitude of 90 degrees can be realized, and the motion characteristic of the periodic large-amplitude flapping of the insect wings can be better simulated;

2. the flapping-wing bionic wing device has the advantages that the flapping-wing bionic wing device realizes the motion with two degrees of freedom by using the pair of flapping mechanisms and the pair of rotating mechanisms, not only can the large-amplitude flapping-wing motion be realized, but also the problems of complexity and heaviness caused by the rotation of the bionic wing driven by a multi-connecting-rod or space mechanism can be reduced;

3. the double-stage speed reducing mechanism can increase the torque and better control the flapping frequency of the ornithopter.

Drawings

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

FIG. 2 is a rear view of the present invention;

FIG. 3 is a schematic diagram of the flapping mechanism 4 of the present invention;

FIG. 4 is an enlarged view of a portion of the flapping mechanism 4 of the present invention;

FIG. 5 is an enlarged view of a portion of the rotating mechanism 5 of the present invention;

FIG. 6 is a schematic view of the structure of the chute 101 of the present invention;

fig. 7 is a schematic structural diagram of a guide block 501 of the present invention.

Detailed Description

The directions of the attached figure 1 in the specification are up, down, left, right, front and back.

As shown in figures 1-2, a motor 2 of the two-degree-of-freedom flapping wing aircraft is fixedly connected to a rack 1, and the relative position of the motor 2 and the rack 1 does not change in the whole flapping wing process. A pair of flapping mechanisms 4 and a pair of rotating mechanisms 5 are arranged on two sides of the rack 1, a fixed rod 7 is fixedly connected to the back of the rack 1, and the fixed rod 7 is hinged to the first two convex blocks 4021 of the flapping mechanisms 4 respectively.

As shown in FIG. 3, the motor shaft and the first gear 201 are coaxially pivoted, and the power of the motor 2 is output through the motor shaft and drives the first gear 201 (Z)₁) Rotating, gear two 301 (Z) of the gear reduction mechanism 3₂) Engages with gear one 201, so that gear two 301 rotates, gear three 302 (Z)₃) The gear II 301 is a concentric gear, the middle part is connected with a transmission rod, the gear III 302 rotates, and the gear IV 303 (Z)₃) Rotation, gear five 304 (Z)₄) Meshing with gear three 302, gear six 305 (Z)₄) And the gear five 304 and the gear six 305 rotate by meshing with the gear four 303, and the rotating speed reducing torque is increased.

As shown in fig. 4, one end of each of two links 401 of the flapping mechanism 4 is hinged to a rocker 402, and the other end is hinged to a fifth gear 304 or a sixth gear 305, respectively. The rocker 402 is rotatably connected with the guide rod 502 through the first projection 4021 and the second projection 4022, the spring 503 is arranged on the guide rod 502 between the first projection 4021 and the second projection 4022, the guide rod 502 between the second projections 4022 is provided with a limiting block, one end of the spring 503 is fixedly connected with the second projection 4022, and the other end of the spring 503 is limited by the limiting block to limit the maximum movement distance.

Referring to fig. 5-7, one end of a guide rod 502 of the rotating mechanism 5 is fixedly connected with a drop-shaped guide block 502, and the other end is connected with the bionic fin 6. The bionic wing 6 is designed in a simulation mode on the basis of the wing shape of a natural insect cicada, the wing shape of the cicada is subjected to parametric design by adopting MATLAB, namely a sample strip difference value method is used, the wing shape of the cicada is fitted into two functions, one part of images of the two functions is the wing shape of the insect, the bionic wing is subjected to mode and deformation analysis by adopting ANSYS, the theoretical flapping frequency of the wing is obtained, and the theoretical flapping frequency of the wing obtains the optimal effect in the second-order mode. Parametric design, modal and deformation analysis are disclosed herein by the prior art. The left side surface and the right side surface of the rack 1 are symmetrically provided with two sliding grooves 101, and the upper end and the lower end of each sliding groove 101 are semicircular arcs. The up-and-down motion of the guide block 501 and the up-and-down flapping of the bionic fin 6 form 180-degree opposite phase. When the bionic fin 6 reaches the two extremes of the flapping stroke, the inner cam rotating mechanism (the sliding chute 101 and the guide block 501) starts to work. Because the up-and-down motion of the guide block 501 and the up-and-down flapping of the bionic fin 6 are set to be in opposite phases, when the bionic fin 6 flaps upwards, the guide block 501 goes downwards, and because the protruding part of the guide block 501 contacts the inner wall of the chute 101 in the rack 1, the guide block 501 is forced to rotate so as to drive the bionic fin 6 to rotate to the vertical direction, and at the moment, the spring 503 is in a compressed state and forces the guide block 501 to go downwards to the bottom of the chute 101 in the rack 1. When the bionic wing 6 reaches the bottom of the chute 101 of the rack 1, the spring 503 is released and the guide block 501 is reset due to the semicircular arc spaces at the upper end and the lower end of the chute 101 in the rack 1, and the bionic wing 6 returns to the initial state. When the bionic fin 6 beats down, the guide block 501 ascends.

Claims

1. A two-degree-of-freedom flapping-wing aircraft is characterized in that: the flapping bionic wing device comprises a rack (1), a motor (2) and a gear reduction mechanism (3), wherein the rack (1) is provided with a pair of flapping mechanisms (4) and a pair of rotating mechanisms (5), the gear reduction mechanism (3) is respectively connected with the motor (2) and the flapping mechanisms (4), sliding grooves (101) are symmetrically formed in the side face of the rack (1), each rotating mechanism (5) comprises a guide block (501), a guide rod (502) and a spring (503), one end of each guide rod (502) is fixedly connected with the corresponding guide block (502), the other end of each guide rod is connected with a bionic wing (6), the guide blocks (502) can rotate along the semi-arc inner walls of the corresponding sliding grooves (101) at the upper end and the lower end of each sliding groove (101) and drive the bionic wings (6) to rotate, the springs (503) are arranged on the corresponding guide rods (502), and the guide rods (502) are.

2. The ornithopter with two degrees of freedom motion of claim 1, wherein: the flapping mechanism (4) comprises a connecting rod (401) and a rocker (402) which are hinged with each other, the rocker (402) is connected with a guide rod (502) through a first projection (4021) and a second projection (4022), and a spring (503) is arranged on the guide rod (502) between the first projection (4021) and the second projection (4022).

3. The ornithopter with two degrees of freedom motion of claim 2, wherein: the back of the rack (1) is provided with a fixing rod (7), and the fixing rod (7) is hinged to first protruding blocks (4021) on two sides of the rack (1) respectively.

4. The ornithopter with two degrees of freedom motion of claim 2, wherein: the motor (2) comprises a first gear (201) and drives the first gear to rotate.

5. The ornithopter with two degrees of freedom motion of claim 1, wherein: the gear reduction mechanism (3) comprises a gear II (301), a gear III (302), a gear IV (303), a gear V (304) and a gear VI (305), the gear II (301) and the gear III (302) are coaxial, the gear III (302) is meshed with the gear IV (303) and the gear V (304) respectively, and the gear IV (303) and the gear VI (305) are meshed.

6. A two degree-of-freedom ornithopter according to claim 4 or 5, wherein: one side of the rack (1) is provided with a first gear (201) and a second gear (301) which are meshed with each other, and the other side of the rack is provided with a third gear (302), a fourth gear (303), a fifth gear (304) and a sixth gear (305).

7. The ornithopter with two degrees of freedom motion of claim 6, wherein: the five gear (304) and the six gear (305) are respectively hinged with the connecting rod (401).

8. The ornithopter with two degrees of freedom motion of claim 5, wherein: the diameters of the gear three (302) and the gear four (303) are the same.

9. The ornithopter with two degrees of freedom motion of claim 5, wherein: the diameters of the gear five (304) and the gear six (305) are the same.

10. The ornithopter with two degrees of freedom motion of claim 1, wherein: the guide block (501) is in a water drop shape.