Flapping-wing robot based on pre-swinging jump flight

Abstract

The invention discloses a flapping-wing robot based on pre-swing jump flight, the flapping-wing robot comprises a rack, and two groups of wing modules, empennage modules, elastic leg modules, control modules and battery modules mounted on the rack, the battery modules supply power to the operation of the control modules, and the control modules control the actions of the wing modules, the empennage modules and the elastic leg modules. The wing module, the empennage module and the elastic leg module work cooperatively, so that the flapping-wing robot takes off autonomously and rapidly. The flapping-wing robot can autonomously complete bird-imitating takeoff and landing under the unmanned assistance condition, initial accelerated motion does not need to be generated by means of a runway, elastic energy does not need to be stored by installing a jumping mechanism capable of actively storing energy, and therefore rapid takeoff within a short time is achieved, and the working efficiency is improved. And the autonomous action ability and the environmental adaptability of the flapping-wing robot in a complex environment are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of robot systems, and in particular to a flapping-wing robot based on pre-swing jumping flight. Background Art

[0002] Bionic flapping-wing robots mimic the movement of bird wings, efficiently generating lift and propulsion in mid-air to achieve flight. However, most current flapping-wing robots rely on external forces for takeoff, such as operator assistance or catapult launch. This reliance on external forces limits flapping-wing robots' autonomous capabilities, making them difficult to adapt to complex and diverse operational scenarios.

[0003] To address the shortcomings of bionic flapping-wing robots in autonomous takeoff, existing flapping-wing robots use the thrust generated by flapping wings to accelerate and launch. This method requires the installation of a mobile mechanism (wheels or legs) on the bottom of the flapping-wing robot, which increases the takeoff time and requires a flat, spacious area. Therefore, it is necessary to design a flapping-wing robot that can achieve autonomous and rapid takeoff while reducing the requirements for the application site. Summary of the Invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a flapping-wing robot based on pre-swing jump flight, which can achieve autonomous and rapid take-off.

[0005] Technical solution: To achieve the above-mentioned purpose, the present invention provides a flapping-wing robot based on pre-swing jumping flight, including a frame, a wing module and a tail module installed on the frame, and an elastic leg module installed at the center of gravity of the abdomen of the frame. The elastic leg module includes a calf, a thigh, and a torsion spring module connecting the calf and the thigh to achieve leg bending or extension. The elastic leg module and the tail module constitute the balance support point of the flapping-wing robot on the ground; the wing module generates aerodynamic lift during the flapping process during takeoff, and the elastic leg module stores elastic potential energy due to pressure. Under the action of aerodynamic lift and elastic potential energy, the flapping-wing robot takes off rapidly.

[0006] Preferably, the wing module includes a skeleton and bionic vanes covering the skeleton. The bionic vanes are in multiple groups and are arranged radially outward with equal angle differences. Adjacent vanes are stacked in sequence from the wing tip to the wing root.

[0007] Preferably, the wing modules are in two groups, symmetrically mounted on both sides of the frame, and there are one or more rotary joints between a single wing module and the frame, wherein the active rotary joint is driven by the wing drive servo to realize the up and down flapping of the wing module.

[0008] Preferably, the tail module is a fan-shaped structure, and is driven by the tail drive servo through a first crank rocker mechanism to flap up and down. The first crank rocker mechanism includes a connecting rod and a tail wing fulcrum connecting piece. One end of the tail wing fulcrum connecting piece is hinged to the tail end of the frame through an axle pin, and the other end is fixed to the mounting point of the tail module. One end of the connecting rod is rotatably connected to the free end of the wing drive servo swing arm, and the other end is rotatably connected to the upper end of the tail wing fulcrum connecting piece.

[0009] Preferably, the elastic leg module is driven by an elastic leg driving servo to adjust the angle with the frame axis.

[0010] Preferably, the elastic leg module is fixed to the frame via a third adapter, and the third adapter is also used to fix the elastic leg driving servo and provide a support point for the swing of the elastic leg module.

[0011] Preferably, the swinging plane of the elastic leg-driven servo swing arm is parallel to the side of the frame, and the free end of the elastic leg-driven servo swing arm drives the elastic leg module to swing through a second crank rocker mechanism. The second crank rocker mechanism includes a connecting rod and a leg fulcrum connecting piece. One end of the connecting rod is rotatably connected to the free end of the elastic leg-driven servo swing arm, and the other end of the connecting rod is rotatably connected to one end of the leg fulcrum connecting piece. The other end of the leg fulcrum connecting piece is hinged to the third adapter through a pin shaft, and elastic leg modules are respectively fixed on both sides of the leg fulcrum connecting piece.

[0012] Preferably, it also includes a control module for controlling the working states of the wing drive servos, the tail drive servos, and the elastic leg drive servos, as well as a battery module for powering the entire machine.

[0013] Preferably, the torsion spring module includes an upper connecting member, a lower connecting member and a torsion spring, wherein the upper connecting member is fixed to the other end of the thigh as the fixed end of the torsion spring, and the lower connecting member is fixed to one end of the calf as the rotating end of the torsion spring.

[0014] Preferably, the flapping-wing robot turns the tail module Generate reverse torque To balance the attack angle of the flapping-wing robot, the equilibrium condition is:

[0015] ,

[0016] in, , K is the tail torque coefficient; is the time-varying torque due to wing flapping, , is the moment of inertia of the flapping-wing robot, is the damping coefficient produced by air, and are the angular velocity and angular acceleration derivatives of the flapping-wing robot's angle of attack, respectively.

[0017] Beneficial effects: The present invention has the following advantages: 1. The flapping-wing robot described in the present invention can independently complete bird-like take-off and landing without human assistance through the coordinated action of the wing module, elastic leg module, etc., and does not need to rely on a runway to generate initial acceleration movement, nor does it need to install an active energy storage jumping mechanism to store elastic energy, thereby achieving rapid take-off in a short time, significantly improving the flapping-wing robot's autonomous action ability and environmental adaptability in complex environments; 2. The design of the bionic feathers of the wing module can enable the flapping-wing robot to maintain a flight state at a lower horizontal speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of the flapping-wing robot;

[0019] Figure 2 Schematic diagram of the rack structure;

[0020] Figure 3 Schematic diagram of the carbon fiber skeleton structure of a single-sided wing module;

[0021] Figure 4 This is a schematic diagram of the structure of a unilateral wing module with the vanes closed;

[0022] Figure 5 This is a schematic diagram of the structure of a single-sided wing module with its vanes fully opened;

[0023] Figure 6 This is a schematic diagram of the structure of a single-sided wing module with the vanes slightly opened;

[0024] Figure 7 Schematic diagram of the structure of the elastic leg module;

[0025] Figure 8 Diagram showing the flapping-wing robot's takeoff process: ① Normal state when standing on the ground, ② State with wings drooping on the ground, ③ State with wings flapping upward at full power, ④ State with wings flapping to the highest position at full power, ⑤ State with wings flapping downward at full power, ⑥ State of the flapping-wing robot taking off and retracting its legs backward.

[0026] In the figure, 1, body frame, 2, wing module, 3, tail module, 4, elastic leg module, 5, control module, 6, battery module, 61, battery fixing part, 11, wing drive servo, 111, first adapter, 112, second adapter 112, 12, tail drive servo, 121, first crank rocker mechanism, 122, tail support rod, 13, elastic leg drive servo, 131, second crank rocker mechanism, 132, third adapter, 41, elastic leg carbon fiber shank, 42, elastic leg carbon fiber Dimensional thigh, 43, torsion spring module, 211, wing main board, 212, main wing spar vane, 213, first support rod vane, 214, second support rod vane, 215, third support rod vane, 216, fourth support rod vane, 22, main wing spar adapter, 23, secondary wing spar adapter, 221, main wing spar, 226, secondary wing spar, 222, first support rod, 223, second support rod, 224, third support rod, 225, fourth support rod, 227, fifth support rod, sixth support rod 228. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is described in detail below with reference to the embodiments and drawings.

[0028] like Figure 1 As shown, the flapping-wing robot of the present invention includes a frame 1, and two sets of wing modules 2, a tail module 3, an elastic leg module 4, a control module 5, and a battery module 6 mounted on the frame 1. The battery module 6 provides power to the control module 5, which controls the movements of the wing modules 2, tail module 3, and elastic leg modules 4. The wing modules 2, tail module 3, and elastic leg modules 4 work together to enable the flapping-wing robot to take off autonomously and quickly.

[0029] like Figure 2 As shown, the frame 1 is a one-piece structure, such as one formed from 3 mm thick carbon fiber laminate using CNC cutting. It has a streamlined, long strip-like shape resembling a bird's body, divided sequentially into the head, back, abdomen, and tail regions. While maintaining structural continuity, the frame features several hollow sections to reduce weight. Through holes are drilled along the contours to secure the wing module 2, tail module 3, elastic leg module 4, control module 5, and battery module 6, as well as the connecting wires between the modules.

[0030] Two sets of wing modules 2 are symmetrically mounted on either side of the frame 1. One set of wing modules 2 is connected to the frame 1 in the following manner: one or more connection points can be set between one set of wing modules 2 and the frame 1 according to the size of the flapping-wing robot. In this embodiment, two connection points are used as an example, located at the head and back of the frame 1, respectively. A wing-driven servo 11 is fixed to the head of the frame 1 via a first adapter 111. The free end of the swing arm of the wing-driven servo 11 is fixedly connected to the front mounting point of the wing module 2, forming the first rotary joint of the flapping-wing robot. The first adapter 111 can be an L-shaped bracket, one side of which is fixed to the side of the frame 1 and the other side is fixed to the mounting hole of the wing-driven servo 11. Alternatively, it can be a square frame with an L-shaped support leg on one side. The wing-driven servo 11 is clamped in the square frame and fixed to the side of the frame 1 via the L-shaped support leg. The plane in which the swing arm of the wing-driven servo 11 swings is perpendicular to the side of the frame 1.

[0031] The back of the chassis 1 is movably connected to the rear mounting point of the wing module 2 via a second adapter 112. This second adapter 112 comprises a base, secured to the side of the chassis 1 by bolts or other means. Two symmetrically arranged lugs are located on the base. The rear mounting point of the wing module 2 is hingedly connected via a pin extending through the lug holes, forming the flapping-wing robot's second rotational joint. This hinge axis is collinear with the output axis of the wing-drive servo 11.

[0032] When the wing driving servo 11 drives the swing arm to swing back and forth, the wing module 2 completes the up and down flapping under the constraints of the first rotary joint and the second rotary joint, generating the lift and thrust required for the flapping-wing robot to fly.

[0033] like Figure 3 As shown, wing module 2 includes a carbon fiber skeleton covered with biomimetic vanes made of MPP flexible foam board. The skeleton is composed of eight carbon fiber rods (221-228) connected by adapters, and all joints are reinforced with metal glue. Specifically, it includes: main spar 221, secondary spar 226, first support rod 222, second support rod 223, third support rod 224, fourth support rod 225, fifth support rod 227, and sixth support rod 228.

[0034] The main spar 221 and the secondary spar 226 are arranged in parallel. One end of the main spar 221 and the secondary spar 226 are respectively connected to the front mounting point and the rear mounting point of the frame 1. The ends of the main spar 221 and the secondary spar 226 are respectively connected to the free end of the swing arm of the wing drive servo 11 and the second adapter 112 through adapters (22, 23).

[0035] The main spar 221 bears the main torque. One end of the fifth support rod 227 and the sixth support rod 228 are fixed to the main spar 221 through an adapter, and the other ends of the fifth support rod 227 and the sixth support rod 228 are fixed to the other end of the secondary spar 226 through an adapter. The fifth support rod 227, the sixth support rod 228 and the main spar 221 form a closed triangle, which improves the in-plane bending stiffness. The first support rod 222 and the second support rod 223 are fixed to the sixth support rod 228 through an adapter to form an outer support. The fourth support rod 225 is fixed to the secondary spar 226 through an adapter. The third support rod 224, together with the fifth support rod 227 and the sixth support rod 228, intersect at the other end of the secondary spar 226, forming a secondary truss and distributing local loads. In the final skeleton, the main wing beam 221, the first support rod 222, the second support rod 223, the third support rod 224, and the fourth support rod 225 are arranged in a radial shape with equal angle differences.

[0036] In this embodiment, the main wing beam 221, the secondary wing beam 226, the first support rod 222, the second support rod 223, the third support rod 224, the fourth support rod 225, the fifth support rod 227, and the sixth support rod 228 can respectively adopt carbon fiber rods with lengths of 30 cm, 11 cm, 12 cm, 11 cm, 6 cm, 5 cm, 12 cm, and 11 cm.

[0037] like Figures 4-6 As shown, the bionic vanes can be cut from 1 mm thick MPP flexible foam board and include vanes (212-216) bonded to the main spar 221 (outside the connection point with the sixth support rod 228), the first support rod 222, the second support rod 223, the third support rod 224, and the fourth support rod 225. Adjacent vanes are stacked sequentially from the wingtip to the wing root, forming an imbricate overlap. During downstroke, the vanes close to increase lift. During upstroke, the vanes deform and rotate around the carbon fiber rod under the influence of air resistance, thereby separating and reducing drag. The trapezoidal area formed by the main spar 221, the secondary spar 226, the fifth support rod 227, and the sixth support rod 228 is also bonded with MPP flexible foam board, serving as the wing main plate 211, filling the gaps in the wing frame and optimizing the airfoil, further improving the lift-to-drag ratio and flight stability.

[0038] like Figure 7As shown, the tail module 3 is a fan-shaped structure made of MPP flexible foam board. It is connected to the frame 1 in the following manner: a tail drive servo 12 is installed at the tail of the frame 1. The plane of the tail drive servo 12's swing arm is parallel to the side of the frame 1. The free end of the tail drive servo 12's swing arm drives the tail module 3 to swing back and forth via a first crank rocker mechanism 121. The first crank rocker mechanism 121 includes a connecting rod and a tail fulcrum connector. One end of the tail fulcrum connector is hinged to the tail end of the frame 1 via a shaft pin, and the other end is fixed to the mounting point of the tail module 3. One end of the connecting rod is rotatably connected to the free end of the tail drive servo 12's swing arm, and the other end is rotatably connected to the upper end of the tail fulcrum connector.

[0039] When the tail-driven servo 12 drives the swing arm to rotate counterclockwise, the first crank rocker mechanism 121 drives the tail module 4 to lift up, increasing the windward area of the flapping-wing robot during flight, thereby increasing the tail torque and increasing the angle of attack of the entire machine; conversely, the tail-driven servo 12 rotates clockwise, causing the tail module 4 to swing down, reducing the windward area, reducing the tail torque, and reducing the angle of attack of the entire machine accordingly.

[0040] The elastic leg module 4 is connected to the frame 1 as follows: the elastic leg drive servo 13 is mounted at the center of gravity of the frame 1's abdomen via a third adapter 132, which also provides a rotational support point for the elastic leg module 4. The third adapter 132 comprises three mutually perpendicular mounting surfaces. The first mounting surface can be bent into a U-shape and secured to the frame 1's abdomen via tension bolts. The second mounting surface is a square frame parallel to the side of the frame 1. The main body of the elastic leg drive servo 13 is retained within this frame, and the plane formed by the swinging arm of the elastic leg drive servo 13 is parallel to the side of the frame 1. Two sets of lugs extend symmetrically from the lower end of the third mounting surface. A second crank-rocker mechanism 131 is installed between the free end of the swing arm of the elastic leg-driven servo 13 and the lugs. The specific connection method is as follows: the second crank-rocker mechanism 131 includes a connecting rod and a leg fulcrum connector. One end of the connecting rod is rotatably connected to the free end of the swing arm of the elastic leg-driven servo 13, and the other end of the connecting rod is rotatably connected to one end of the leg fulcrum connector. The other end of the leg fulcrum connector is hinged to the two sets of lugs on the third mounting surface via a pin. On both sides of the leg fulcrum connector, symmetrical deep-hole adhesive bonding is used to connect the mounting points of the elastic leg module 4. At the same time, the two sets of lugs on the third mounting surface must leave room for the elastic leg module 4 to move, that is, these two sets of lugs do not interfere with the movement of the mounting point of the elastic leg module 4.

[0041] Driven by the elastic leg driving servo 13 , the second crank rocker mechanism 131 drives the elastic leg module 4 to swing back and forth, thereby adjusting the angle between the elastic leg module 4 and the axis of the frame 1 .

[0042] The flapping-wing robot's elastic leg module 4 includes a calf 41 and a thigh 42. One end of the thigh 42 is the mounting point for connecting the elastic leg module 4 to the frame 1. Specifically, it is installed on the side of the leg fulcrum connector, tilted toward the outside of the frame 1. The other end of the thigh 42 is connected to the calf 41 via a torsion spring module 43. Both the calf 41 and the thigh 42 can be made of carbon fiber rods.

[0043] The torsion spring module 43 includes an upper connector, a lower connector, and a torsion spring. The upper connector is fixed to the other end of the thigh 42, serving as the fixed end of the torsion spring; the lower connector is fixed to one end of the calf 41, serving as the rotating end of the torsion spring. This enables relative rotational movement between the thigh 42 and calf 41, provides a certain rebound force or auxiliary torque, and can achieve leg bending or extension by adjusting the angle between the thigh and calf.

[0044] In this embodiment, the elastic leg drive servo 13 drives the second crank-rocker mechanism 131, allowing the angle between the thigh 42 and the frame axis to be continuously adjustable within a range of 20° to 90°. When the flapping-wing robot is stationary on the ground, the angle between the thigh 42 and the frame axis can be adjusted to 90°. When the flapping-wing robot is in flight, the angle between the thigh 42 and the frame axis can be adjusted to 20°. When the elastic leg module 4 is free of external force, the angle between the thigh 42 and the shank 41 can be adjusted to 10°. When the flapping-wing robot is stationary on the ground and subjected to the action of gravity, the angle between the thigh 42 and the shank 41 increases. During takeoff, the periodic lift generated by the flapping of the wing module 2 and gravity act together on the elastic leg module 4, causing the torsion spring module 43 to compress and rebound the shank 41, thereby storing and releasing elastic potential energy.

[0045] A tail support rod 122 is also fixed to the rear of the frame 1. Together with the two lower legs 41, this rod forms a three-point support structure, forming an isosceles triangle with a horizontal projection. In this embodiment, the tail support rod 122 is a 2 mm diameter straight-pull carbon fiber rod. By combining the length of the tail support rod 122 with the static load deformation of the elastic leg module 4, the flapping-wing robot maintains a 30° elevation angle (the angle between the frame axis and the horizontal plane) when stationary on the ground.

[0046] The control module 5 is directly fixed to the belly of the frame 1, above the elastic leg module 4. It has four onboard servo interfaces, which are connected to the two sets of wing-driven servos 11, the tail-driven servos 12, and the elastic leg-driven servos 13 via flat cables. The control module 5 is used to control the operating status of the wing-driven servos 11, the tail-driven servos 12, and the elastic leg-driven servos 13. It also includes an MPU9050 attitude sensor chip for real-time acquisition of data such as the aircraft's pitch, roll, and yaw.

[0047] The battery module 6, typically a rectangular lithium battery pack, is located behind the control module 5. To facilitate installation and removal of the battery module 6, a suitable chute for the battery module can be provided on the chassis 1. Fixing members 61 are fixed to the chute areas on both sides of the chassis 1. These fixing members 61 are arranged parallel and staggered in the chute areas to limit the position of the battery module 6 when inserted into the chute. The battery module 6 is connected to the power port of the control module 5 via a DuPont cable, providing stable power to the entire machine.

[0048] like Figure 8 As shown, the process of rapid takeoff of the flapping-wing robot of the present invention is as follows:

[0049] In Phase 1, the flapping-wing robot is in a normal standby state on the ground. The flapping-wing robot is supported by two legs of the elastic leg module 4 and the tail support rod 122, forming a stable three-point support structure. Under the action of gravity, the torsion spring module 43 in the elastic leg module 4 drives the shank 41 to produce a slight angle of deflection.

[0050] In the second stage, the flapping-wing robot enters a takeoff preparation state, wherein the wing module 2 is adjusted to the lowest position by the wing driving servo 11, and the tail module 3 is lifted up by the tail driving servo 12.

[0051] Phase 3: Initial State 1 of the flapping-wing robot's takeoff. Control module 5 controls the wing drive servo 11 to propel wing module 2 upward at maximum angular velocity. The oncoming aerodynamic force causes the bionic vanes to passively bend, transiently widening the gaps between adjacent vanes and significantly reducing air resistance. Simultaneously, the body's gravity and inertial forces are transmitted via thigh 42 to torsion spring module 43, compressing the torsion spring and storing elastic potential energy, providing additional power reserve for the subsequent downward stroke.

[0052] Phase 4: Initial State 2 of the flapping-wing robot takeoff. When the wing module 2 is lifted to the highest position, the instantaneous angular velocity of the wing is zero, the vanes are closed, and the elastic leg module 4 is compressed to the maximum extent.

[0053] Phase five is the critical stage for the flapping-wing robot to take off. The control module 5 controls the wing drive servo 11 to drive the wing module 2 to flap downward at the maximum angular velocity. The bionic vanes form a continuous wing surface due to overlapping limits, which significantly generates aerodynamic lift in the forward-upward direction. At this time, the torsion spring module 43 rebounds quickly, releasing the elastic potential energy stored in phase three as an additional upward thrust, which is superimposed with the aerodynamic force vector; the angle between the thigh 42 and the calf 41 of the elastic leg module 4 increases accordingly, and the ground reaction force decreases to zero. At the same time, the tail drive servo 12 drives the tail module 3 to swing downward, generating a reverse pitching torque to offset the upward tendency of the body and maintain overall longitudinal balance. Under the synergistic effect of the above-mentioned aerodynamic force, elastic force and tail torque, the flapping-wing robot instantly leaves the ground and completes takeoff.

[0054] Phase 6: After the flapping-wing robot takes off. After the flapping-wing robot becomes airborne, the wing drive servo 11 adjusts the flapping frequency of the wing module 2 to 50%-80%, reducing the gap between the vanes when the wings are raised. The elastic leg drive servo 13 also drives the elastic leg module 4 toward the tail to optimize the flight posture and enter a stable flight state.

[0055] The biomimetic vanes of the flapping-wing robot described in this invention exhibit controllable flexible deformation during periodic flapping. As the flapping frequency changes, the vanes undergo varying degrees of coupled bending and torsional deformation due to the combined effects of aerodynamic and inertial forces. At low frequencies, the vanes exhibit minimal curvature and the overlapping region remains closed. As the frequency increases, the vanes tilt upward and the overlapping region partially opens, achieving adaptive aerodynamic adjustment that increases lift during the downstroke phase and reduces drag during the upstroke phase.

[0056] In stage three, when the wing-driven servo 11 drives the wing module 2 to lift, the oncoming airflow acts on each bionic vane, causing it to produce passive flexible deformation; thus, a controllable gap appears between adjacent vanes. The gap opening is monotonically increasing with the angular velocity of the lift, that is, the higher the angular velocity, the greater the bending angle of the vane, and the wider the gap. When the wing-driven servo 11 drives the wing module 2 to lift at the maximum angular velocity, the instantaneous bending angle of the vane end relative to the wing plane can reach about 90°. At this time, the gap area is the largest, the airflow rate is significantly improved, and the negative lift and drag peaks are effectively suppressed. The kinetic energy stored by the flapping-wing robot in this stage is recorded as :

[0057] ,

[0058] in, It is the vertical aerodynamic force generated by the flapping-wing robot on the fuselage during the process of the wings lifting up. Its direction is downward and its magnitude changes with time. It is the vertical elastic force of the elastic leg module when it is compressed when the vertical position of the fuselage is lowered, and the direction is upward; is the mass of the flapping-wing robot; is the acceleration due to gravity; is the velocity at the center of gravity of the flapping-wing robot; 0~T1 is the time period when the wing module is lifted from the lowest position to the highest position at the maximum angular velocity.

[0059] The elastic leg module 4 will transfer the kinetic energy generated by the wing module 2 ( ) is converted into elastic potential energy for short-term storage. If the loss in the energy conversion process is ignored, the stored elastic potential energy can be expressed as:

[0060] .

[0061] In stage five, when the wings reach their highest position and transition to a downstroke, the overlapping bionic vanes are unable to bend upward due to the mechanical restraint of the trailing vane on the preceding one. The gaps between adjacent vanes are completely closed, and the wing surface instantly forms a continuous, low-permeability load-bearing surface. This state significantly increases the effective frontal area and circulation, thereby generating net positive lift even at zero horizontal initial velocity. In contrast, the average lift of a traditional kite fabric airfoil approaches zero when there is no initial velocity because it cannot establish effective circulation.

[0062] During the downward movement, the body accelerates upward due to the lift force, and at the same time, the elastic leg module 4 is compressed and releases the stored elastic potential energy synchronously, exerting an additional upward impulse on the body. The vertical increment of the kinetic energy of the flapping-wing robot in this stage is recorded as :

[0063] ,

[0064] in, It is the resultant vertical aerodynamic force exerted on the body of the flapping-wing robot when its wings flap downwards, and its direction is upward; It is the elastic force generated on the fuselage during the deformation recovery process of the elastic leg module, and its direction is upward; T1~T2 is the time period when the wing module moves from the highest position to the lowest position at the maximum angular velocity.

[0065] If the loss of elastic potential energy during storage and release is not considered, then:

[0066] . ,

[0067] Furthermore, the vertical component of the total kinetic energy generated by the flapping-wing robot during the wing lift-down cycle (stages 3 to 5) is for:

[0068] ,

[0069] Further expressed as:

[0070] ,

[0071] in, represents the vertical velocity of the flapping-wing robot at time T2, and are the distances that the center of gravity of the flapping-wing robot moves up and down during the process of lifting and flapping the wings.

[0072] Since the elastic legs are in close contact with the ground during the wing lift, no effective horizontal thrust is generated. Therefore, the horizontal component of the kinetic energy during the takeoff cycle (phases 2 to 3) is mainly generated by the wing downstroke phase (T1-T2), which can be expressed as:

[0073] ,

[0074] in, is the horizontal component of the kinetic energy of the flapping-wing robot at time T2, The thrust generated by the wings. is the kinetic energy of the flapping-wing robot at time T2.

[0075] When the flapping-wing robot takes off (stage six), the magnitude of the lift is related to the flight speed. Within a certain range, the faster the flight speed, the greater the lift generated.

[0076] Under the same wingbeat frequency and angle of attack, the lift of the flapping-wing robot is Size and horizontal flight speed Positive correlation ( Right now ), the conditions for the flapping-wing robot to take off successfully are: the thrust generated by flapping wings after taking off Acceleration makes the horizontal flight speed Reaching a sufficient threshold, Increase to overcome gravity ( , is the gravity acting on the flapping-wing robot, is the mass size, is the magnitude of the acceleration due to gravity). At the same time, the rising speed of the flapping-wing robot when it separates from the ground is defined as .

[0077] When lift It has not yet grown enough to overcome gravity When the flapping-wing robot is in the air, it must not lower its altitude and touch the ground.

[0078] The resultant force on the flapping-wing robot in the vertical direction after it takes off is:

[0079] ,

[0080] According to Newton's second law:

[0081] ,

[0082] is the vertical acceleration of the flapping-wing robot, and its value changes with time.

[0083] Furthermore, we can obtain:

[0084] ,

[0085] According to acceleration being the derivative of velocity:

[0086] ,

[0087] The velocity expression is obtained by integration:

[0088] ,

[0089] Since velocity is the derivative of height, we can get:

[0090] ,

[0091] in, Indicates the height of the flapping-wing robot after it takes off.

[0092] Integrate to get the height:

[0093] ,

[0094] Further expressed as:

[0095] .

[0096] The condition for the flapping-wing robot to take off successfully after being airborne is that the flapping-wing robot will not land again, that is, when When There is no solution.

[0097] From the above derivation formula, we can get the initial rising speed The larger the The larger it is, the easier it is for the equation to have no solution, that is, the flapping-wing robot successfully takes off.

[0098] The wing module 4 used in the present invention is designed to imitate the vane structure, which can effectively improve the average lift during low-speed flight, thereby ensuring that the flapping-wing robot can effectively achieve the take-off process.

[0099] The present invention uses the tail module 3 to balance the torque of the flapping-wing robot during the fifth and sixth takeoff stages. The balance control process is as follows:

[0100] Wing flapping produces a time-varying torque , through the tail deflection angle Generate reverse torque Balancing the angle of attack of a flapping-wing robot; the torque of the wings The angular acceleration and angular velocity monitored by the sensor can be obtained:

[0101] ,

[0102] in, is the moment of inertia of the flapping-wing robot, is the damping coefficient produced by air, is the angle of attack of the flapping-wing robot. and They represent the first-order (angular velocity) and second-order (angular acceleration) derivatives of the attack angle of the flapping-wing robot, respectively.

[0103] At the same time, the torque generated by the tail wing can be expressed as:

[0104] ;

[0105] Torque balance needs to meet the following requirements:

[0106] .

[0107] In order to further optimize the control, the PID control method is used to achieve smooth control:

[0108] ,

[0109] in is the angle deviation term, is the desired angle of attack of the flapping-wing aircraft during flight, K is the tail torque coefficient, 、 、 These are the proportional gain coefficient, integral gain coefficient, and differential gain coefficient of the PID control. The 0 to t term in the integral gain coefficient is the control unit time. In this case program, t=100 milliseconds.

[0110] The control module 5 is equipped with a communication module (Bluetooth / Wifi), which can send remote control commands through the remote control or mobile phone APP to start the flapping-wing robot's take-off function.

[0111] During the flight phase, the control module 5 precisely controls the altitude by adjusting the PWM duty cycle (flapping power) of the wing drive servo 11 and the pitch angle of the tail drive servo 12 in real-time closed-loop mode: the flapping power is limited to 50%–80%, and this range enables the vanes to maintain a continuous wing surface that is just closed under the action of aerodynamic forces, ensuring stable circulation and sufficient lift, while avoiding excessive opening of the vanes, circulation rupture, and stall caused by an excessively high duty cycle; the tail pitch angle increases and decreases synchronously with the power, causing the lift vector inclination angle to change accordingly, thereby achieving altitude rise and fall.

[0112] Steering is achieved by differential wing flapping frequency: when turning left, the frequency of the right wing increases and the frequency of the left wing decreases, generating a left yaw moment; turning right reverses the direction.

[0113] During landing, the wingbeat frequency drops to 30%–50%. This threshold ensures that the feathers produce only slight deformation, the lift decays rapidly, and a smooth descent is achieved. The elastic leg drives the servo 13 to drive the carbon fiber thigh 42 forward for buffering, and the tail drives the servo 12 to increase the pitch angle to provide negative lift to suppress sinking. After touching the ground, the control module 5 immediately turns off all PWMs to complete the landing.

Claims

1. A flapping-wing robot based on pre-swing jump flight, comprising a frame (1), a wing module (2) and a tail module (3) mounted on the frame (1), characterized in that: The invention also includes an elastic leg module (4) installed at the center of gravity of the abdomen of the frame (1), the elastic leg module (4) including a calf (41), a thigh (42), and a torsion spring module (43) connecting the calf (41) and the thigh (42) to achieve leg bending or extension, and the elastic leg module (4) and the tail wing module (3) constitute a balance support point of the flapping-wing robot on the ground; the wing module (2) generates aerodynamic lift during the flapping process during takeoff, and the elastic leg module (4) stores elastic potential energy due to pressure. Under the action of the aerodynamic lift and the elastic potential energy, the flapping-wing robot takes off quickly.

2. The flapping-wing robot according to claim 1, characterized in that: The wing module (2) comprises a skeleton and bionic vanes covering the skeleton, wherein the bionic vanes are in multiple groups and are arranged radially outwards with equal angle differences, and adjacent vanes are stacked in sequence from the wing tip to the wing root.

3. The flapping-wing robot according to claim 1, characterized in that: The wing modules (2) are in two groups and are symmetrically mounted on both sides of the frame (1). There are one or more rotary joints between a single wing module (2) and the frame (1), wherein the active rotary joint is driven by the wing drive servo (11) to achieve the up and down flapping of the wing module (2).

4. The flapping-wing robot according to claim 1, characterized in that: The tail module (3) is a fan-shaped structure, and is driven by the tail driving servo (12) through a first crank rocker mechanism (121) to fan up and down. The first crank rocker mechanism (121) includes a connecting rod and a tail fulcrum connecting piece. One end of the tail fulcrum connecting piece is hinged to the tail end of the frame (1) through an axle pin, and the other end is fixed to the installation point of the tail module (3). One end of the connecting rod is rotatably connected to the free end of the swing arm of the tail driving servo (12), and the other end is rotatably connected to the upper end of the tail fulcrum connecting piece.

5. The flapping-wing robot according to claim 1, characterized in that: The elastic leg module (4) is driven by the elastic leg driving servo (13) to adjust the angle between the module and the axis of the frame (1).

6. The flapping-wing robot according to claim 5, characterized in that: The elastic leg module (4) is fixed to the frame (1) via a third adapter (132); the third adapter (132) is also used to fix the elastic leg driving servo (13) and provide a support point for the swing of the elastic leg module (4).

7. The flapping-wing robot according to claim 6, characterized in that: The swing plane of the swing arm of the elastic leg driving servo (13) is parallel to the side of the frame (1), and the free end of the swing arm of the elastic leg driving servo (13) drives the elastic leg module (4) to swing through the second crank rocker mechanism (131). The second crank rocker mechanism (131) includes a connecting rod and a leg fulcrum connecting piece, one end of the connecting rod is rotatably connected to the free end of the swing arm of the elastic leg driving servo (13), and the other end of the connecting rod is rotatably connected to one end of the leg fulcrum connecting piece, and the other end of the leg fulcrum connecting piece is hinged to the third adapter (132) through a pin shaft, and the elastic leg modules (4) are respectively fixed on both sides of the leg fulcrum connecting piece.

8. The flapping-wing robot according to any one of claims 3, 4, and 5, characterized in that: It also includes a control module (5) for controlling the working states of the wing drive servo (11), the tail drive servo (12), and the elastic leg drive servo (13), and a battery module (6) for supplying power to the entire machine.

9. The flapping-wing robot according to claim 1, characterized in that: The torsion spring module (43) includes an upper connecting member, a lower connecting member and a torsion spring, wherein the upper connecting member is fixed to the other end of the thigh (42) as the fixed end of the torsion spring, and the lower connecting member is fixed to one end of the calf (41) as the rotating end of the torsion spring.

10. The flapping-wing robot according to claim 1, characterized in that: The flapping wing robot turns the corner by means of the tail wing module (3) Generate reverse torque To balance the attack angle of the flapping-wing robot, the equilibrium condition is: ， in, , K is the tail torque coefficient; is the time-varying torque due to wing flapping, , is the moment of inertia of the flapping-wing robot, is the damping coefficient produced by air, and are the angular velocity and angular acceleration derivatives of the flapping-wing robot's angle of attack, respectively.

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