Flapping-wing air vehicle with multi-degree-of-freedom empennage cooperatively moving and control method

Abstract

The invention provides an ornithopter with multi-degree-of-freedom empennage collaborative movement and a control method.The ornithopter comprises a rack, empennage bodies and an empennage driving mechanism, each empennage body comprises an empennage support, a plurality of tail feather bodies, a traction rope guide wheel and a tail feather elastic rope, and one end of each tail feather body is sequentially hinged to one end of the empennage support; the number of the traction rope guide wheels is two, the traction rope guide wheels are arranged in the middle of the empennage support side by side, the tail feather elastic rope is sequentially connected to the multiple tail feather bodies, and the two tail feather bodies on the outermost side are each provided with a connecting part extending towards the other side of the hinged end. The empennage driving mechanism comprises an empennage connecting pipe assembly, a traction steering engine, a winding roll, a traction rope, an empennage torsion steering engine, an empennage deflection steering engine and an empennage pitching steering engine. According to the empennage structure, independent control or combined control of torsion, pitching, deflection and opening and closing actions can be achieved, and the problems that an existing ornithopter empennage mechanism is insufficient in motion freedom degree and lacks an efficient wing-empennage cooperative motion system are solved.

Description

Technical Field

[0001] The present invention relates to the field of flapping-wing aircraft, and in particular to a flapping-wing aircraft with coordinated movement of multiple-degree-of-freedom tail wings and a control method thereof. Background Art

[0002] In recent years, the continuous development of the low-altitude economy has spawned micro-aircraft (MAVs) for various applications. Flapping-wing aircraft, in particular, have garnered widespread attention in fields such as reconnaissance and disaster relief due to their superior flexibility, stealth, and low-altitude flight performance. However, compared to birds, existing bird-like flapping-wing aircraft still lack the high maneuverability at low Reynolds numbers, such as the rapid climbs, turns, and dives seen in bird flight.

[0003] Existing research shows that a bird's tail does more than just maintain balance during flight. Thanks to its flexible tail structure, birds can dynamically adjust the folding of their wings according to actual flight conditions, while simultaneously coordinating the tail's twist, pitch, yaw, and opening and closing movements. This creates a highly efficient aerodynamic coupling effect, enabling highly maneuverable, low-energy flight. However, current bird-like flapping-wing aircraft still face challenges such as an inability to achieve a high-degree-of-freedom tail structure similar to that of birds and a lack of an efficient wing-tail coordinated motion system. Summary of the Invention

[0004] In order to solve the problem of insufficient freedom of tail movement in the prior art, the present invention provides a flapping-wing aircraft with multi-degree-of-freedom tail coordinated movement and a control method in order to solve the problems raised in the background technology, that is, the current bird-like flapping-wing aircraft still have the inability to achieve a high-degree-of-freedom tail structure similar to that of birds and the lack of an efficient wing-tail coordinated motion system.

[0005] The present invention provides a flapping-wing aircraft with multi-degree-of-freedom tail-wing coordinated movement, comprising a frame, a tail wing body and a tail wing drive mechanism, wherein the tail wing body comprises a tail wing bracket, a tail feather body, a traction rope guide wheel and a tail feather elastic rope, the tail feather bodies are multiple and one end of which is hinged to one end of the tail wing bracket in sequence, the traction rope guide wheels are two and are arranged in parallel at the middle position of the tail wing bracket, the tail feather elastic rope is connected to the multiple tail feather bodies in sequence, and the two outermost tail feather bodies are respectively provided with a connection portion extending to the other side of the hinged end; the tail wing drive mechanism comprises a tail wing connecting pipe assembly with one end rotatably connected to the frame, a traction servo fixed on the frame, a winding reel connected to the traction servo, The traction rope with one end is wound around the winding reel, the tail torsion servo is fixed on the frame, and the tail yaw servo and tail pitch servo are fixed on the left and right sides of the tail connecting tube assembly. The other end of the tail connecting tube assembly is connected to the other end of the tail bracket through a universal cross shaft. The tail torsion servo is hinged to one side of the tail connecting tube assembly through a first crank-connecting rod mechanism, the tail yaw servo is hinged to one side of the tail bracket through a second crank-connecting rod mechanism, and the tail pitch servo is connected to the upper end of the universal cross shaft through a third crank-connecting rod mechanism. The other end of the traction rope is divided into two and is fixedly connected to the connecting parts of the two outermost tail feather bodies after passing through the two traction rope guide wheels.

[0006] As a further improvement of the present invention, the tail wing bracket includes two upper and lower tail wing support plates, two support plates and two universal joint positioning plates. The upper and lower tail wing support plates are connected by the two support plates. One end of the two universal joint positioning plates is fixedly connected to the upper and lower tail wing support plates by screws, and the other end is connected to the upper and lower ends of the universal cross shaft respectively.

[0007] As a further improvement of the present invention, the tail feather main body includes a tail feather fixing tube, a tail feather carbon rod, a tail feather skeleton and a tail feather film, one end of the tail feather fixing tube is hinged to the two tail wing support plates, one end of the tail feather carbon rod is fixedly connected to the other end of the tail feather fixing tube, the other end of the tail feather carbon rod is fixedly connected to the tail feather skeleton, the tail feather film is attached to the tail feather skeleton, and the tail feather elastic rope is connected to multiple tail feather carbon rods in sequence.

[0008] As a further improvement of the present invention, the tail wing connecting tube assembly includes a tail wing fixed flange, a tail wing rotating circular tube, a tail wing connecting sleeve, a tail wing square tube and a tail universal joint fork. The outer periphery of the tail wing connector is provided with a connecting flange, the tail wing fixed flange is fixed on the frame and a bearing is embedded inside. One end of the tail wing rotating circular tube is interference fit with the bearing in the tail wing fixed flange, the other end of the tail wing rotating circular tube is connected to one end of the tail wing square tube through the tail wing connecting sleeve, the other end of the tail wing square tube is fixedly connected to the tail universal joint fork, and the left and right ends of the universal cross shaft are hinged to the tail universal joint fork.

[0009] As a further improvement of the present invention, the traction rope passes through the tail wing fixing flange, the tail wing rotating circular tube, the tail wing connecting sleeve, the tail wing square tube, the tail universal joint fork and the universal cross shaft.

[0010] As a further improvement of the present invention, the frame is formed by splicing two carbon fiber plates that are arranged horizontally and vertically crosswise.

[0011] As a further improvement of the present invention, the flapping-wing aircraft also includes a power mechanism, a wing assembly and a wing drive mechanism fixed to the frame, the wing assembly is composed of two groups respectively arranged on both sides of the frame, the power mechanism includes a brushless motor, a first gear connected to the output end of the brushless motor, a second gear meshed with the first gear, a third gear coaxial with the second gear, a fourth gear meshed with the third gear and a fifth gear connected to the fourth gear through a main shaft, the fourth gear and the fifth gear are respectively arranged on both sides of the frame, and a fourth crank-connecting rod mechanism is respectively provided at both ends of the main shaft.

[0012] As a further improvement of the present invention, the wing assembly includes a left wing and a right wing symmetrically arranged on both sides of the frame and having the same structure, the left wing includes a wing end, a wing middle, a wing tip, a wing swing block, a wing guide rod bracket, a wing guide rod, a cross slider, a first wing pull rod, a first wing connecting rod, a second wing pull rod and a second wing connecting rod, the wing guide rod bracket is two and is fixed to the front and rear ends of the frame by screws, the wing guide rod is fixed between the two wing guide rod brackets by a bearing, the cross slider passes through the wing guide rod and can slide back and forth along the wing guide rod, the wing swing block is fixed to the wing guide rod by screws, one end of the wing end is connected to the wing guide rod The swing block is hinged, one end of the first wing pull rod is hinged to the cross slider, and the other end is hinged to the middle part of the wing end; one end of the first wing connecting rod is hinged to the middle part of the first wing pull rod, and the other end is hinged to one end of the second wing connecting rod; the two ends of the middle part of the wing are respectively hinged to the other end of the wing end and one end of the wing tip; one end of the second wing pull rod is hinged to the middle part of the first wing connecting rod, and the other end is connected to a connection in the middle of the wing close to the wing end; the other end of the second wing connecting rod is hinged to an end of the wing tip close to the middle of the wing; the free end of the fourth crank-connecting rod mechanism is connected to one end of the wing end close to the wing swing block.

[0013] As a further improvement of the present invention, the wing drive mechanism includes a wing telescopic servo and a fifth crank-connecting rod mechanism. The wing telescopic servo is fixed to one end of the wing guide rod away from the wing swing block. One end of the fifth crank-connecting rod mechanism is connected to the output end of one of the telescopic servos, and the other end is hinged to the cross slider.

[0014] The present invention also discloses a control method for a flapping-wing aircraft with coordinated movement of a multi-degree-of-freedom tail, which is applied to the above-mentioned flapping-wing aircraft and includes the following steps:

[0015] Step S1: When the aircraft is in the takeoff and climbing stage, the controller controls the brushless motor to accelerate forward rotation, thereby driving the wing assemblies on both sides of the frame to finally maintain a 5Hz frequency of flapping up and down. At this time, the controller controls the wing telescopic servos of the wing drive mechanisms on both sides to swing at the same frequency, so that the reciprocating folding-extension motion and flapping motion of the wing assemblies on both sides are performed simultaneously. At this time, the wingtip motion trajectory of the aircraft is "O"-shaped, generating lift and thrust. At the same time, the controller controls the traction servo of the tail drive mechanism to rotate forward to a suitable angle and then remain stationary. At this time, the traction rope will be pulled tight to keep the tail open, and the controller synchronously controls the tail pitch servo in the tail drive mechanism that controls the tail pitch motion to rotate to a suitable angle to press the tail down.

[0016] Step S2: When the aircraft is in the yaw turning stage, the controller controls the brushless motor to rotate forward, driving the wing assemblies on both sides of the frame to flap up and down at a frequency of 5 Hz. At this time, the controller controls the wing telescopic servo on the same side as the aircraft is turning to rotate in the opposite direction, so that the wing assembly on that side remains in a folded state, while the wing telescopic servo on the other side rotates forward, so that the wing assembly on that side remains in an unfolded state. At the same time, the controller controls the tail torsion servo fixed on the frame to rotate to the side opposite to the turning direction, driving the tail to twist in the direction of rotation of the tail pitch servo. At the same time, the controller controls the traction servo in the tail to rotate forward to the appropriate angle and then remain stationary, thereby pulling the traction line taut to keep the tail at the maximum opening and closing area and continuously adjusting the torsion angle of the tail according to the bank angle of the aircraft.

[0017] Step S3: When the aircraft is in the dive phase, the controller controls the brushless motor to reduce the speed, so that the flapping frequency of the wing assemblies on both sides is reduced from 5Hz to 2~3Hz. At the same time, the controller controls the wing telescopic servos of the wing drive mechanisms on both sides to rotate in the opposite direction at the same time, so that the wings on both sides remain in a folded state at the same time. Due to the reduction of lift and the forward center of gravity of the aircraft, after entering the dive posture for 1~2s, the controller controls the traction servo in the tail wing to rotate in the opposite direction to the appropriate angle and then remain motionless. At this time, the tension of the traction rope on the tail feather fixing tubes on the left and right sides of the tail wing is reduced. At the same time, the tension acting on each tail feather carbon rod when the tail feather elastic rope rebounds causes the originally unfolded tail feathers to gradually converge toward the middle. At this time, the tail area is greatly reduced, which can reduce the resistance during the dive and accelerate the dive speed of the aircraft. At the same time, the controller dynamically controls the tail wing pitch servo to rotate to the appropriate angle according to the actual situation of the aircraft, so that the deformable tail wing dynamically adjusts the pitch angle to maintain the balance of the aircraft.

[0018] The beneficial effect of the present invention is that: the present invention uses a universal joint structure and a pull rope structure to enable the designed tail structure to achieve independent or combined control of torsion, pitch, yaw and opening and closing movements, so as to solve the current problem of insufficient freedom of movement of the tail mechanism of flapping-wing aircraft and the lack of an efficient wing-tail coordinated motion system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of a flapping-wing aircraft with coordinated movement of multiple degrees of freedom tail wings according to the present invention;

[0020] Figure 2 This is a schematic diagram of the frame structure of a flapping-wing aircraft with coordinated movement of multiple degrees of freedom tail wings according to the present invention;

[0021] Figure 3 This is a schematic structural diagram of a tail drive mechanism for a flapping-wing aircraft with coordinated tail motion of multiple degrees of freedom according to the present invention;

[0022] Figure 4This is a schematic structural diagram of a tail support for a flapping-wing aircraft with coordinated tail movement of multiple degrees of freedom according to the present invention;

[0023] Figure 5 This is a schematic structural diagram of the tail feather main body of a flapping-wing aircraft with coordinated movement of the tail wing with multiple degrees of freedom according to the present invention;

[0024] Figure 6 It is a partial cross-sectional view of the tail body of a flapping-wing aircraft with coordinated movement of the tail with multiple degrees of freedom according to the present invention;

[0025] Figure 7 This is a schematic structural diagram of the unfolded tail feathers of a flapping-wing aircraft with coordinated tail-wing motion of multiple degrees of freedom according to the present invention;

[0026] Figure 8 This is a schematic diagram of the structure of the tail feather folding of a flapping-wing aircraft with coordinated movement of the tail wing with multiple degrees of freedom according to the present invention;

[0027] Figure 9 This is a schematic structural diagram of a power mechanism of a flapping-wing aircraft with coordinated movement of multiple degrees of freedom tail wings according to the present invention;

[0028] Figure 10 This is a schematic structural diagram of a power mechanism of a flapping-wing aircraft with coordinated tail movement of multiple degrees of freedom according to the present invention, mounted on a frame;

[0029] Figure 11 This is a schematic structural diagram of a wing assembly of a flapping-wing aircraft with coordinated tail movement of multiple degrees of freedom according to the present invention;

[0030] Figure 12 This is a schematic structural diagram of a wing drive mechanism for a flapping-wing aircraft with coordinated tail movement of multiple degrees of freedom according to the present invention;

[0031] Figure 13 This is a flow chart of a control method for the takeoff and climbing phase of a flapping-wing aircraft with coordinated tail movement of multiple degrees of freedom according to the present invention;

[0032] Figure 14 This is a flow chart of a control method for a flapping-wing aircraft with coordinated tail movement of multiple degrees of freedom during a turning phase according to the present invention;

[0033] Figure 15 The present invention is a flow chart of a control method for a flapping-wing aircraft in the dive phase with coordinated tail movement of multiple degrees of freedom.

[0034] Figure 1: Frame; 2: Power mechanism; 201: Brushless motor; 202: First gear; 203: Second gear; 204: Third gear; 205: Fourth gear; 206: Fifth gear; 207: Main shaft; 208: Fourth crank-connecting rod mechanism; 3: Tail body; 301: Tail support plate; 302: Support plate; 303: Universal shaft positioning plate; 304: Tail feather fixing tube; 305: Traction rope guide wheel; 306: Tail feather carbon rod; 307: Tail feather skeleton; 308: Tail feather film; 309: Tail feather elastic rope; 4: Wing drive mechanism; 401: Wing telescopic servo; 402: Fifth crank-connecting rod mechanism; 5: Tail drive mechanism; 501: Tail fixing flange; 502: Tail rotating tube; 503: -Tail connecting sleeve; 504-Tail square tube; 505-Tail universal joint fork; 506-Traction servo; 507-Reel; 508-Traction rope; 509-Tail torsion servo; 510-Tail yaw servo; 511-Tail pitch servo; 512-Universal cross shaft; 513-First crank-connecting rod mechanism; 514-Second crank-connecting rod mechanism; 515-Third crank-connecting rod mechanism; 6-Wing assembly; 601-Wing end; 602-Wing middle; 603-Wing tip; 604-Wing swing block; 605-Wing guide rod bracket; 606-Wing guide rod; 607-Cross slider; 608-First wing pull rod; 609-First wing connecting rod; 610-Second wing pull rod; 611-Second wing connecting rod. DETAILED DESCRIPTION

[0035] In the description of the present invention, it should be understood that if there are descriptions involving orientation, such as orientations or positional relationships indicated by up, down, front, back, left, and right, the orientation descriptions may be based on the orientations or positional relationships shown in the accompanying drawings. These descriptions are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0036] In the description of the present invention, if there is a quantity, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of the terms "first" and "second" is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0037] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0038] like Figures 1 to 12 As shown, the present invention discloses a flapping-wing aircraft with multi-degree-of-freedom tail-wing coordinated movement, including a frame 1, a tail wing body 3 and a tail wing driving mechanism 5, wherein the tail wing body 3 includes a tail wing bracket, a tail feather body, a traction rope guide wheel 305 and a tail feather elastic rope 309, wherein the tail feather body is multiple and one end is hinged to one end of the tail wing bracket in sequence, the traction rope guide wheel 305 is two and is arranged in parallel at the middle position of the tail wing bracket, the tail feather elastic rope 309 is connected to the multiple tail feather bodies in sequence, and the two outermost tail feather bodies are respectively provided with a connecting portion extending to the other side of the hinged end; the tail wing driving mechanism 5 includes a tail wing connecting pipe assembly with one end rotatably connected to the frame 1, a traction servo 506 fixed on the frame 1, a winding drum 507 connected to the traction servo 506, and a wire reel 507 with one end wound on the winding drum. The traction rope 508 on the reel 507, the tail torsion servo 509 fixed on the frame 1, and the tail yaw servo 510 and the tail pitch servo 511 fixed on the left and right sides of the tail connecting tube assembly, the other end of the tail connecting tube assembly is connected to the other end of the tail bracket through a universal cross shaft 512, the tail torsion servo 509 is hinged to one side of the tail connecting tube assembly through a first crank-connecting rod mechanism 513, the tail yaw servo 510 is hinged to one side of the tail bracket through a second crank-connecting rod mechanism 514, the tail pitch servo 511 is connected to the upper end of the universal cross shaft 512 through a third crank-connecting rod mechanism 515, and the other end of the traction rope 508 is divided into two, which are respectively passed around the two traction rope guide wheels 305 and fixedly connected to the connecting parts of the two outermost tail feather bodies.

[0039] In the present invention, the tail wing bracket includes two upper and lower tail wing support plates 301, two support plates 302 and two universal joint positioning plates 303. The upper and lower tail wing support plates 301 are connected by the two support plates 302. One end of the two universal joint positioning plates 303 is fixedly connected to the upper and lower tail wing support plates 301 by screws, and the other end is connected to the upper and lower ends of the universal cross shaft 512 respectively.

[0040] In the present invention, the tail feather body includes a tail feather fixing tube 304, a tail feather carbon rod 306, a tail feather skeleton 307, and a tail feather film 308. One end of the tail feather fixing tube 304 is hinged to the two tail wing support plates 301, one end of the tail feather carbon rod 306 is fixedly connected to the other end of the tail feather fixing tube 304, and the other end of the tail feather carbon rod 306 is fixedly connected to the tail feather skeleton 307. The tail feather film 308 is attached to the tail feather skeleton 307, and the tail feather elastic rope 309 is sequentially connected to multiple tail feather carbon rods 306. When installed, the tail feather fixing tube 304 in the present invention is symmetrical with the tail wing central axis as the installation height, and the installation height gradually decreases to both sides, so that the tail feathers are stacked in a tile-like layer.

[0041] In the present invention, the tail connecting tube assembly includes a tail fixing flange 501, a tail rotating circular tube 502, a tail connecting sleeve 503, a tail square tube 504 and a tail universal joint fork 505. The outer periphery of the tail connecting piece is provided with a connecting flange. The tail fixing flange 501 is fixed on the frame 1 and has a bearing embedded therein. One end of the tail rotating circular tube 502 is interference fit with the bearing in the tail fixing flange 501. The other end of the tail rotating circular tube 502 is connected to one end of the tail square tube 504 through the tail connecting sleeve 503. The other end of the tail square tube 504 is fixedly connected to the tail universal joint fork 505. The left and right ends of the universal cross shaft 512 are hinged to the tail universal joint fork 505.

[0042] In the present invention, the traction rope 508 passes through the tail fixing flange 501 , the tail rotating circular tube 502 , the tail connecting sleeve 503 , the tail square tube 504 , the tail universal joint fork 505 and the universal cross shaft 512 .

[0043] In the present invention, the frame 1 is formed by splicing two carbon fiber plates that are arranged horizontally and vertically crosswise.

[0044] In the present invention, the flapping-wing aircraft also includes a power mechanism 2, a wing assembly 6 and a wing drive mechanism 4 fixed on the frame 1. The wing assembly 6 is divided into two groups and is respectively arranged on both sides of the frame 1. The power mechanism 2 includes a brushless motor 201, a first gear 202 connected to the output end of the brushless motor 201, a second gear 203 engaged with the first gear 202, a third gear 204 coaxial with the second gear 203, a fourth gear 205 engaged with the third gear 204, and a fifth gear 206 connected to the fourth gear 205 through a main shaft 207. The fourth gear 205 and the fifth gear 206 are respectively arranged on both sides of the frame 1, and a fourth crank-connecting rod mechanism 208 is respectively provided at both ends of the main shaft 207.

[0045] In the present invention, the wing assembly 6 includes a left wing and a right wing symmetrically arranged on both sides of the frame 1 and having the same structure. The left wing includes a wing end 601, a wing middle 602, a wing tip 603, a wing swing block 604, a wing guide rod bracket 605, a wing guide rod 606, a cross slider 607, a first wing pull rod 608, a first wing connecting rod 609, a second wing pull rod 610 and a second wing connecting rod 611. The wing guide rod bracket 605 is two and is fixed to the front and rear ends of the frame 1 by screws. The wing guide rod 606 is fixed between the two wing guide rod brackets 605 by bearings. The cross slider 607 passes through the wing guide rod 606 and can slide back and forth along the wing guide rod 606. The wing swing block 604 is fixed to the wing guide rod 606 by screws. One end of the wing end 601 is connected to the wing swing Block 604 is hinged, one end of the first wing pull rod 608 is hinged to the cross slider 607, and the other end is hinged to the middle part of the wing end 601, one end of the first wing connecting rod 609 is hinged to the middle part of the first wing pull rod 608, and the other end is hinged to one end of the second wing connecting rod 611, the two ends of the wing middle part 602 are respectively hinged to the other end of the wing end 601 and one end of the wing tip 603, one end of the second wing pull rod 610 is hinged to the middle part of the first wing connecting rod 609, and the other end is connected to a connection of the wing middle part 602 close to the wing end 601, the other end of the second wing connecting rod 611 is hinged to an end of the wing tip 603 close to the wing middle part 602, and the free end of the fourth crank-connecting rod mechanism 208 is connected to one end of the wing end 601 close to the wing swing block 604.

[0046] In the present invention, the wing drive mechanism 4 includes a wing telescopic servo 401 and a fifth crank-connecting rod mechanism 402. The wing telescopic servo 401 is fixed to one end of the wing guide rod 606 away from the wing swing block 604. One end of the fifth crank-connecting rod mechanism 402 is connected to the output end of one of the telescopic servos, and the other end is hinged to the cross slider 607.

[0047] Through the wing drive mechanism 4, the rotational motion of the wing telescopic servo 401 can be converted into the forward and backward sliding of the cross slide 607, thereby enabling the unilateral wing to complete the folding motion.

[0048] The present invention uses a universal joint structure and a pull rope structure to enable the designed tail structure to achieve independent or combined control of torsion, pitch, yaw and opening and closing movements, thereby solving the problem of insufficient movement freedom of the tail mechanism of current flapping-wing aircraft.

[0049] like Figures 13 to 15As shown, the present invention also discloses a control method for a flapping-wing aircraft with coordinated movement of a multi-degree-of-freedom tail, which is applied to the above-mentioned flapping-wing aircraft and includes the following steps:

[0050] Step S1: When the aircraft is in the takeoff and climbing stage, the controller controls the brushless motor 201 to accelerate forward rotation, thereby driving the wing assemblies 6 on both sides of the frame 1 to finally maintain a 5Hz frequency of flapping up and down. At this time, the controller controls the wing telescopic servos 401 of the wing drive mechanisms 4 on both sides to swing at the same frequency, so that the reciprocating folding-extension motion and flapping motion of the wing assemblies 6 on both sides are performed simultaneously. At this time, the wingtip motion trajectory of the aircraft is "O"-shaped, generating lift and thrust. At the same time, the controller controls the traction servo 506 of the tail drive mechanism 5 to rotate forward to a suitable angle and then remain stationary. At this time, the traction rope 508 will be pulled tight to keep the tail open, and the controller synchronously controls the tail pitch servo 511 in the tail drive mechanism 5 that controls the tail pitch motion to rotate to a suitable angle to press the tail down.

[0051] During the takeoff and climbing phase, the folded wings move in an "O"-shaped trajectory to provide sufficient lift and thrust for the aircraft, and the deformable tail that moves in coordination with it keeps the tail feathers open and pressed down, which not only generates a downward aerodynamic torque to avoid stalling due to excessive angle of attack caused by the forward movement of the wing lift, but also increases the downwash speed of the tail airflow, generates additional lift, increases the climbing speed of the aircraft, and further shortens the time required for the aircraft to climb to the predetermined height.

[0052] Step S2: When the aircraft is in the yaw turning stage, the controller controls the brushless motor 201 to rotate forward, driving the wing assemblies 6 on both sides of the frame 1 to flap up and down at a frequency of 5 Hz. At this time, the controller controls the wing telescopic servo 401 on the same side as the aircraft is turning to rotate in the opposite direction, so that the side wing assembly 6 remains in a folded state, while the wing telescopic servo 401 on the other side rotates forward, so that the side wing assembly 6 remains in an unfolded state. At the same time, the controller controls the tail torsion servo 509 fixed on the frame 1 to rotate to the side opposite to the turning direction, driving the tail to twist in the direction of rotation of the tail pitch servo 511. At the same time, the controller controls the traction servo 506 in the tail to rotate forward to a suitable angle and then remain stationary, thereby pulling the traction line taut to keep the tail at the maximum opening and closing area and continuously adjusting the torsion angle of the tail according to the bank angle of the aircraft.

[0053] When the aircraft is in the yaw turning stage, the imbalance in the wing areas on both sides will cause the lift of the wings on both sides to be imbalanced, which in turn causes the aircraft to generate the rolling torque required for turning. At this time, the tail feathers of the tail wing are synchronously controlled to expand to the maximum area and the tail wing is controlled to twist to the appropriate angle toward the opposite side of the turning. This can not only maintain the balance of the aircraft during the turn, but also the twisting of the tail wing will increase the fuselage angle of attack of the aircraft, thereby reducing the situation where the aircraft's flying altitude drops due to lift imbalance during the turn. The twisted tail wing can also generate a yaw moment around the center of gravity of the aircraft, allowing the aircraft to trigger steering more efficiently.

[0054] Step S3: When the aircraft is in the dive phase, the controller controls the brushless motor 201 to reduce the speed, so that the flapping frequency of the wing assemblies 6 on both sides is reduced from 5Hz to 2-3Hz. At the same time, the controller controls the wing telescopic servos 401 of the wing drive mechanisms 4 on both sides to rotate in the opposite direction at the same time, so that the wings on both sides remain in a folded state at the same time. Due to the reduction of lift and the forward center of gravity of the aircraft, after entering the dive posture for 1-2 seconds, the controller controls the traction servo 506 in the tail wing to rotate in the opposite direction to a suitable angle and then remain motionless. At this time, the pulling force of the traction rope 508 on the tail feather fixing tubes 304 on the left and right sides of the tail wing is reduced. At the same time, the tension acting on each tail feather carbon rod 306 when the tail feather elastic rope 309 rebounds causes the originally unfolded tail feathers to gradually retract toward the middle. At this time, the tail area is greatly reduced, which can reduce the resistance during the dive and accelerate the dive speed of the aircraft. At the same time, the controller dynamically controls the tail wing pitch servo 511 to rotate to a suitable angle according to the actual situation of the aircraft, so that the deformable tail wing dynamically adjusts the pitch angle to maintain the balance of the aircraft.

[0055] When the aircraft is in the dive phase, the rotation speed of the brushless motor 201 is controlled to reduce the flapping frequency of the left and right wings, and the wing retracting servos 401 on the left and right sides of the wings are controlled to keep the wings on both sides in a folded state with the same wingspan area. This allows the aircraft to quickly enter a dive state. At this time, the tail is further controlled to retract and the tail feather area is reduced, which can further reduce the air resistance encountered by the aircraft during a dive, increase the dive speed, and effectively improve the maneuverability of the aircraft.

[0056] The present invention proposes a control method for realizing wing-tail coordinated motion, so as to solve the problem that the coordinated motion effect of the tail and wings of flapping-wing aircraft is single at present.

[0057] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the scope of protection of the present invention.

Claims

1. A flapping-wing aircraft with coordinated tail movement of multiple degrees of freedom, characterized by: The tail wing comprises a frame, a tail wing body and a tail wing driving mechanism, the tail wing body comprises a tail wing bracket, a tail feather body, a traction rope guide wheel and a tail feather elastic rope, the tail feather bodies are multiple and one end is hinged to one end of the tail wing bracket in sequence, the traction rope guide wheels are two and are arranged in parallel at the middle position of the tail wing bracket, the tail feather elastic rope is connected to the multiple tail feather bodies in sequence, and the two outermost tail feather bodies are respectively provided with a connecting part extending to the other side of the hinged end; the tail wing driving mechanism comprises a tail wing connecting pipe assembly with one end rotatably connected to the frame, a traction servo fixed on the frame, a winding drum connected to the traction servo, a traction cable with one end wound on the winding drum The traction rope is divided into two parts, which are respectively passed around two traction rope guide wheels and are fixed to the connecting parts of the two outermost tail feather bodies.

2. The flapping-wing aircraft with multi-degree-of-freedom tail coordinated motion according to claim 1, characterized in that: The tail wing bracket includes two upper and lower tail wing support plates, two support plates and two universal joint positioning plates. The upper and lower tail wing support plates are connected by the two support plates. One end of the two universal joint positioning plates is fixedly connected to the upper and lower tail wing support plates by screws, and the other end is connected to the upper and lower ends of the universal cross shaft respectively.

3. The flapping-wing aircraft with multi-degree-of-freedom tail coordinated motion according to claim 2, characterized in that: The tail feather main body includes a tail feather fixing tube, a tail feather carbon rod, a tail feather skeleton and a tail feather film. One end of the tail feather fixing tube is hinged to the two tail wing support plates, one end of the tail feather carbon rod is fixedly connected to the other end of the tail feather fixing tube, and the other end of the tail feather carbon rod is fixedly connected to the tail feather skeleton. The tail feather film is attached to the tail feather skeleton, and the tail feather elastic rope is connected to multiple tail feather carbon rods in sequence.

4. The flapping-wing aircraft with multi-degree-of-freedom tail coordinated motion according to claim 1, characterized in that: The tail connecting tube assembly includes a tail fixing flange, a tail rotating circular tube, a tail connecting sleeve, a tail square tube and a tail universal joint fork. A connecting flange is provided on the periphery of the tail connecting piece. The tail fixing flange is fixed on the frame and embedded with a bearing. One end of the tail rotating circular tube is interference fit with the bearing in the tail fixing flange. The other end of the tail rotating circular tube is connected to one end of the tail square tube through the tail connecting sleeve. The other end of the tail square tube is fixedly connected to the tail universal joint fork. The left and right ends of the universal cross shaft are hinged to the tail universal joint fork.

5. The flapping-wing aircraft with multi-degree-of-freedom tail coordinated motion according to claim 4, characterized in that: The traction rope passes through the tail wing fixing flange, the tail wing rotating circular tube, the tail wing connecting sleeve, the tail wing square tube, the tail universal joint fork and the universal cross shaft.

6. The flapping-wing aircraft with multi-degree-of-freedom tail coordinated motion according to claim 1, characterized in that: The frame is formed by splicing two carbon fiber plates that are cross-arranged horizontally and vertically.

7. The flapping-wing aircraft with multi-degree-of-freedom tail coordinated motion according to claim 1, characterized in that: The flapping-wing aircraft also includes a power mechanism, a wing assembly and a wing drive mechanism fixed to the frame. The wing assembly is divided into two groups and is respectively arranged on both sides of the frame. The power mechanism includes a brushless motor, a first gear connected to the output end of the brushless motor, a second gear meshed with the first gear, a third gear coaxial with the second gear, a fourth gear meshed with the third gear and a fifth gear connected to the fourth gear through a main shaft. The fourth gear and the fifth gear are respectively arranged on both sides of the frame, and a fourth crank-connecting rod mechanism is respectively provided at both ends of the main shaft.

8. The flapping-wing aircraft with multi-degree-of-freedom tail coordinated motion according to claim 7, characterized in that: The wing assembly includes a left wing and a right wing symmetrically arranged on both sides of the frame and having the same structure, the left wing including a wing end, a wing middle, a wing tip, a wing swing block, a wing guide rod bracket, a wing guide rod, a cross slider, a first wing pull rod, a first wing connecting rod, a second wing pull rod and a second wing connecting rod, the wing guide rod bracket is two and fixed to the front and rear ends of the frame by screws, the wing guide rod is fixed between the two wing guide rod brackets by a bearing, the cross slider passes through the wing guide rod and can slide back and forth along the wing guide rod, the wing swing block is fixed to the wing guide rod by screws, and one end of the wing end is hinged to the wing swing block, One end of the first wing pull rod is hinged to the cross slider, and the other end is hinged to the middle part of the wing end; one end of the first wing connecting rod is hinged to the middle part of the first wing pull rod, and the other end is hinged to one end of the second wing connecting rod; the two ends of the middle part of the wing are respectively hinged to the other end of the wing end and one end of the wing tip; one end of the second wing pull rod is hinged to the middle part of the first wing connecting rod, and the other end is connected to a connection in the middle part of the wing close to the wing end; the other end of the second wing connecting rod is hinged to an end of the wing tip close to the middle part of the wing; the free end of the fourth crank-connecting rod mechanism is connected to one end of the wing end close to the wing swing block.

9. The flapping-wing aircraft with multi-degree-of-freedom tail coordinated motion according to claim 8, characterized in that: The wing drive mechanism includes a wing telescopic servo and a fifth crank-connecting rod mechanism. The wing telescopic servo is fixed to the end of the wing guide rod away from the wing swing block. One end of the fifth crank-connecting rod mechanism is connected to the output end of one of the telescopic servos, and the other end is hinged to the cross slider.

10. A control method for a flapping-wing aircraft with coordinated tail movement of multiple degrees of freedom, applied to the flapping-wing aircraft according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step S1: When the aircraft is in the takeoff and climbing phase, the controller controls the brushless motor to accelerate forward rotation, thereby driving the wing assemblies on both sides of the frame to eventually maintain a 5Hz frequency of flapping up and down. At this time, the controller controls the wing extension and retraction servos of the wing drive mechanisms on both sides to swing at the same frequency, so that the reciprocating folding-extension motion and flapping motion of the wing assemblies on both sides are performed simultaneously. At this time, the wingtip motion trajectory of the aircraft is "O"-shaped, generating lift and thrust. At the same time, the controller controls the traction servo of the tail drive mechanism to rotate forward to an appropriate angle and then remain stationary. At this time, the traction rope will be pulled tight to keep the tail open, and the controller synchronously controls the tail pitch servo in the tail drive mechanism that controls the tail pitch motion to rotate to an appropriate angle to press the tail down. Step S2: When the aircraft is in the yaw turning stage, the controller controls the brushless motor to rotate forward, driving the wing assemblies on both sides of the frame to flap up and down at a frequency of 5 Hz. At this time, the controller controls the wing telescopic servo on the same side as the aircraft is turning to rotate in the opposite direction, so that the wing assembly on that side remains in a folded state, while the wing telescopic servo on the other side rotates forward, so that the wing assembly on that side remains in an unfolded state. At the same time, the controller controls the tail torsion servo fixed on the frame to rotate to the side opposite to the turning direction, driving the tail to twist in the direction of rotation of the tail pitch servo. At the same time, the controller controls the traction servo in the tail to rotate forward to the appropriate angle and then remain stationary, thereby pulling the traction line taut to keep the tail at the maximum opening and closing area and continuously adjusting the torsion angle of the tail according to the bank angle of the aircraft. Step S3: When the aircraft is in the dive phase, the controller controls the brushless motor to reduce the speed, so that the flapping frequency of the wing assemblies on both sides is reduced from 5Hz to 2~3Hz. At the same time, the controller controls the wing telescopic servos of the wing drive mechanisms on both sides to rotate in the opposite direction at the same time, so that the wings on both sides remain in a folded state at the same time. Due to the reduction of lift and the forward center of gravity of the aircraft, after entering the dive posture for 1~2s, the controller controls the traction servo in the tail wing to rotate in the opposite direction to the appropriate angle and then remain motionless. At this time, the tension of the traction rope on the tail feather fixing tubes on the left and right sides of the tail wing is reduced. At the same time, the tension acting on each tail feather carbon rod when the tail feather elastic rope rebounds causes the originally unfolded tail feathers to gradually converge toward the middle. At this time, the tail area is greatly reduced, which can reduce the resistance during the dive and accelerate the dive speed of the aircraft. At the same time, the controller dynamically controls the tail wing pitch servo to rotate to the appropriate angle according to the actual situation of the aircraft, so that the deformable tail wing dynamically adjusts the pitch angle to maintain the balance of the aircraft.

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