Energy recovery system and control method for semi-active flapping wing power generation device

Abstract

The present application belongs to the technical field of energy recovery and utilization, and relates to an energy recovery and utilization system and a control method for a semi-active flapping wing power generation device. The system comprises a movement module and two hydraulic energy storage and conversion assemblies symmetrically arranged on both sides of the movement module. Each hydraulic energy storage and conversion assembly is provided with a piezoelectric assembly on the side close to the movement module. When the driving device touches the piezoelectric assembly, the hydraulic energy storage and conversion assembly recovers and stores the kinetic energy in the flapping wing sinking and floating movement in the form of hydraulic pressure. When the flapping wing moves to the limit position, the hydraulic energy storage and conversion assembly releases the stored energy to drive the flapping wing to realize the sinking and floating pitch coupling movement. Compared with the prior art, the present application introduces the hydraulic energy storage and conversion assembly in the sinking and floating process of the flapping wing, optimizes the sinking and pitch coordination of the flapping wing, effectively improves the energy collection efficiency, reduces the external energy input, and improves the system efficiency, economy and operation stability.

Description

Energy recovery and utilization system and control method for semi-active flapping-wing power generation device Technical Field

[0001] This invention belongs to the field of energy recovery and utilization technology, specifically relating to an energy recovery and utilization system and control method for a semi-active flapping wing power generation device. Background Technology

[0002] Flapping-wing energy harvesting devices, as a biomimetic energy conversion method, possess high energy capture potential under low-speed flow conditions, and have therefore gradually become a research hotspot in academia and engineering in recent years. The basic motion of the flapping wing includes two degrees of freedom: buoyancy and pitch, and the coordination between the two directly determines the energy conversion efficiency.

[0003] In existing technologies, the buoyancy of semi-active flapping wing energy harvesting technology mainly relies on lift. Currently proposed semi-active flapping wing energy harvesting devices often use a short spring or other buffer mechanism at the end of the flapping motion to cushion the movement. However, during most of the motion cycle, the flapping wing experiences almost no significant drag, often exhibiting a "free-rising" or "free-falling" state. This lack of damping and constraint causes a severe asynchrony between the buoyancy velocity and the direction of fluid lift, weakening the lift's contribution to energy capture and causing a phase mismatch between pitch and buoyancy. Furthermore, the pitch motion of flapping wings generally requires a large driving torque to overcome fluid resistance and structural inertia. If this torque is provided solely by a drive device or other active drive device, it will lead to excessive energy consumption, significantly limiting system efficiency and economy. Summary of the Invention

[0004] In view of this, the present invention provides an energy recovery and utilization system and control method for a semi-active flapping wing power generation device, solving the technical problems in the prior art.

[0005] The technical solution of this invention is:

[0006] An energy recovery and utilization system for a semi-active flapping wing power generation device includes a motion module and two hydraulic energy storage and conversion components symmetrically arranged on both sides of the motion module;

[0007] The motion module includes a drive unit, a flapping wing, and a motion conversion mechanism. The output shaft of the drive unit is connected to one end of the flapping wing. The motion conversion mechanism includes a main bevel gear, a connecting bracket, two Morse taper cylinders, and two auxiliary bevel gears. The main bevel gear is fixedly fitted to the rotating shaft at the other end of the flapping wing. The two auxiliary bevel gears are respectively located on both sides of the main bevel gear and mesh with the main bevel gear. Each auxiliary bevel gear is coaxially fitted and fixed to a Morse taper cylinder. The connecting bracket is rotatably connected to the Morse taper cylinder and the rotating shaft at the other end of the flapping wing, respectively.

[0008] The hydraulic energy storage and conversion assembly includes a hydraulic damper, a check valve, a first solenoid valve, a high-pressure accumulator, a pressure reducing valve, a low-pressure accumulator, a second solenoid valve, and a hydraulic motor connected in sequence. It also includes an external oil tank, a piezoelectric component, and a Morse taper. The first solenoid valve and the hydraulic damper are respectively connected to the external oil tank. The piezoelectric component is located at the piston rod end of the hydraulic damper and is located on the side of the drive device. The rotor of the hydraulic motor is parallel to the piston rod of the hydraulic damper and is located on the side closer to the drive device. The Morse taper is coaxially mounted on the rotor of the hydraulic motor and is coaxially opposite to the Morse taper.

[0009] When the drive unit touches the piezoelectric component, the hydraulic energy storage and conversion component recovers and stores the kinetic energy of the flapping wing's floating and sinking motion in hydraulic form. When the flapping wing moves to its limit position, the Morse cone and the Morse cone head match, and the hydraulic energy storage and conversion component releases the stored energy, driving the flapping wing to achieve floating, sinking, and pitching coupled motion.

[0010] Furthermore, a spline sleeve and a spline shaft are provided between the rotor of the hydraulic motor and the Morse taper. The spline sleeve is coaxially fixed at the end of the rotor of the hydraulic motor. The spline shaft passes through the spline sleeve and meshes with the spline sleeve. One end of the spline shaft is coaxially fixed to the Morse taper, and the other end is connected to the inside of the spline sleeve through a reset structure.

[0011] Furthermore, the reset structure includes multiple springs, with both ends of the springs fixedly connected to the spline shaft and the spline sleeve, respectively.

[0012] Furthermore, the piezoelectric assembly includes a piezoelectric sensor and a control unit electrically connected to the piezoelectric sensor. The piezoelectric sensor is located at the end of the piston rod of the hydraulic damper, and the control unit is electrically connected to the drive device.

[0013] Furthermore, it also includes a support body and a first guide structure and a second guide structure that are spaced apart vertically on the support body. The first guide structure includes a first slider and a first slide rail on the support body. The driving device is fixed on the first slider and the first slider is mounted on the first slide rail. The second guide structure includes a second slider and a second slide rail on the support body. The second slide rail is parallel to the first slide rail and the second slider is mounted on the second slide rail. The connecting bracket is connected to the second slider.

[0014] Furthermore, the control unit is electrically connected to an angle sensor for detecting the rotation angle of the flapping wing. The angle sensor is fixed on the second slider, and the rotor of the angle sensor is connected to the rotating shaft at the other end of the flapping wing. The connecting bracket is connected to the angle sensor.

[0015] Furthermore, the connecting bracket includes a first ring, a second ring, a third ring, and two cranks. The first ring and the third ring are coaxially arranged, and the central axis of the first ring and the central axis of the second ring are perpendicular. The first ring and the second ring, as well as the second ring and the third ring, are connected by cranks. The second ring is fitted and fixed on the angle sensor. The first ring and the second ring are rotatably connected to a Morse taper cylinder, respectively.

[0016] Furthermore, the driving device includes a servo motor and a frame mounted on the servo motor, wherein the servo motor and the frame are respectively fixed to the first slider.

[0017] A control method, based on the above system implementation, includes the following steps:

[0018] Energy storage stage:

[0019] Close the second solenoid valve, open the first solenoid valve to the outlet of the high-pressure accumulator and close the outlet switch to the external oil tank, open the pressure reducing valve, and supply oil to the oil cylinder of the hydraulic buffer through the external oil tank until the oil cylinder of the hydraulic buffer is full of hydraulic oil.

[0020] The drive unit is activated, and the initial pitch angle of the flapping wing is set to the first limit angle, causing the entire motion module to perform a floating motion until the frame contacts the piezoelectric sensor on one side. The piezoelectric sensor then feeds back the received pressure signal to the control unit, activating the drive unit to drive the flapping wing to perform a pitching motion. At the same time, the frame compresses the hydraulic buffer to charge the high-pressure accumulator and the low-pressure accumulator. When the pitch angle of the flapping wing is detected to be the second limit angle, the drive unit stops operating, and oil is added to the hydraulic buffer until the piston rod of the hydraulic buffer returns to its initial position. When the motion module contacts the piezoelectric sensor on the other side, the above method is repeated until the high-pressure accumulator and the low-pressure accumulator on both sides reach the maximum pressure standard.

[0021] Kinetic energy recovery and utilization stage:

[0022] After the high-pressure and low-pressure accumulators on both sides reach their maximum pressure standards, when the frame contacts the piezoelectric sensor on one side, the piezoelectric sensor feeds back the received pressure signal to the control unit, shuts off the power supply to the drive device, and opens the second solenoid valve. At this time, the low-pressure accumulator begins to release energy, driving the hydraulic motor to run. The high-pressure accumulator continuously replenishes energy to the low-pressure accumulator to ensure the stable operating pressure of the hydraulic motor. At the same time, the oil pressure in the hydraulic buffer continuously increases until it exceeds the pressure of the high-pressure accumulator, at which point it begins to replenish the pressure to the high-pressure accumulator. When the Morse cone and Morse cone head on one side of the motion conversion mechanism are fitted together, the secondary bevel gear is driven to rotate. The secondary bevel gear drives the main bevel gear to rotate, thereby driving the flapping wing and the angle sensor rotor to rotate, realizing the coupled motion of sinking, floating, and pitching.

[0023] Furthermore, during the energy storage phase, when the high-pressure accumulators and low-pressure accumulators on both sides reach the maximum pressure standard and the piston rod of the hydraulic buffer is in a compressed state, the outlet switch of the first solenoid valve to the high-pressure accumulator is closed, and the outlet switch of the first solenoid valve to the external oil tank is opened until the motion module moves in the opposite direction and no longer applies pressure to the piston rod of the hydraulic buffer, at which point the state of the first solenoid valve is restored.

[0024] Compared with existing technologies, the energy recovery and utilization system and control method for a semi-active flapping wing power generation device provided by this invention introduces hydraulic energy storage and conversion components during the flapping wing's buoyancy process. This not only allows for the artificial setting of resistance in the buoyancy channel, controlling the buoyancy motion and synchronizing it with the lift direction, but also enables the efficient recovery and reuse of buoyancy energy, thereby fully utilizing the energy contribution of the flapping wing's lift, optimizing the buoyancy and pitch coordination of the flapping wing, and effectively improving energy harvesting efficiency. Furthermore, this invention, through a hydraulic energy storage and release mechanism, partially relies on the hydraulic energy storage and conversion components to drive the flapping wing to complete the flapping wing pitch motion or the coupled buoyancy and pitch motion via a motion conversion mechanism. This reduces dependence on drive devices or other active drive devices, effectively reducing the instantaneous pitch torque requirement, reducing external energy input, and improving system efficiency, economy, and operational stability. It is highly practical and worthy of promotion. Attached Figure Description

[0025] Figure 1 is an overall structural diagram of the present invention.

[0026] Figure 2 is a structural schematic diagram of the support body and hydraulic energy storage and conversion component bracket of the present invention.

[0027] Figure 3 is a schematic diagram of the motion module of the present invention.

[0028] Figure 4 is a schematic diagram of the gear transmission mechanism of the present invention.

[0029] Figure 5 is a cross-sectional view of the gear transmission mechanism of the present invention.

[0030] Figure 6 is a schematic diagram of the structure of the hydraulic energy storage and conversion component of the present invention.

[0031] Figure 7 is a schematic diagram of the structure of the hydraulic energy storage and conversion component of the present invention.

[0032] Figure 8 is a graph showing the sinking and floating speed and lift under buffered and unbuffered conditions during one cycle of the flapping wing sinking and floating process in this invention through numerical simulation.

[0033] Figure 9 is a graph showing the torque curves of the flapping wing sinking and floating process with and without buffering during one cycle in the numerical simulation of this invention.

[0034] Figure label:

[0035] 1. Support body; 2. Motion module; 3. Motion conversion mechanism; 4. Hydraulic energy storage and conversion component bracket; 5. Hydraulic energy storage and conversion component; 6. Drive device; 7. Frame; 8. First slider; 9. Coupling; 10. Flapping wing; 11. Secondary bevel gear; 12. Morse taper cylinder; 13. Main bevel gear; 14. Connecting bracket; 15. Angle sensor; 16. Second slider; 17. Hydraulic shock absorber; 18. Piezoelectric sensor; 19. High-voltage accumulator; 20. Low-voltage accumulator; 21. Hydraulic motor; 22. Check valve; 23. First solenoid valve; 24. Pressure reducing valve; 25. Second solenoid valve; 26. Spline. Detailed Implementation

[0036] Flapping-wing energy harvesting devices, as a biomimetic energy conversion method, possess high energy capture potential under low-speed flow conditions, and have therefore gradually become a research hotspot in academia and engineering in recent years. The basic motion of the flapping wing includes two degrees of freedom: buoyancy and pitch, and the coordination between the two directly determines the energy conversion efficiency.

[0037] In existing technologies, the buoyancy of semi-active flapping wing energy harvesting technology mainly relies on lift. Currently proposed semi-active flapping wing energy harvesting devices often use a short spring or other buffer mechanism at the end of the flapping motion to cushion the movement. However, during most of the motion cycle, the flapping wing experiences almost no significant drag, often exhibiting a "free-rising" or "free-falling" state. This lack of damping and constraint causes a severe asynchrony between the buoyancy velocity and the direction of fluid lift, weakening the lift's contribution to energy capture and causing a phase mismatch between pitch and buoyancy. Furthermore, the pitch motion of flapping wings generally requires a large driving torque to overcome fluid resistance and structural inertia. If this torque is provided solely by a drive device or other active drive device, it will lead to excessive energy consumption, significantly limiting system efficiency and economy.

[0038] Existing research shows that appropriately setting drag during the buoyancy process can not only suppress the free acceleration motion of the flapping wing, making the buoyancy speed and lift direction better synchronized, but also effectively reduce the instantaneous torque required for pitching motion. The introduction of drag is equivalent to providing "adjustment" and "buffering" effects, making buoyancy and pitching more dynamically coordinated. However, if this drag is only used as an additional burden for energy consumption and is not utilized, it will inevitably reduce the overall energy utilization efficiency. Based on this, the present invention provides an energy recovery and utilization system and control method for a semi-active flapping wing power generation device to solve the above-mentioned problems. In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the technical solution of the present invention will be clearly and thoroughly described below with reference to the accompanying drawings.

[0039] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0040] Furthermore, it should be further explained that in the description of the embodiments of the present invention, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present invention, "multiple" means two or more.

[0041] The terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first," "second," "third," or "fourth" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0044] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this invention are for illustrative purposes only and do not represent the only possible implementation.

[0045] Example 1

[0046] The energy recovery and utilization system for the semi-active flapping wing power generation device, as shown in Figures 1 and 2, includes a motion module 2 and two hydraulic energy storage and conversion components 5 symmetrically arranged on both sides of the motion module 2. The motion module 2 and the two hydraulic energy storage and conversion components 5 are all mounted on the support body 1.

[0047] There are two hydraulic energy storage and conversion component brackets 4, which are respectively installed on opposite sides of the support body 1, for mounting two hydraulic energy storage and conversion components 5 respectively. Each hydraulic energy storage and conversion component bracket 4 includes a first plate, a second plate, a third plate, and a fourth plate, wherein the first plate, the second plate, and the third plate are arranged sequentially and parallel to each other, one end of the first plate, the second plate, and the third plate are fixedly connected to the fourth plate, and the fourth plate is fixedly connected to the support body 1.

[0048] Specifically, as shown in Figure 3, which is a schematic diagram of the structure of the motion module 2 of the present invention, the motion module 2 includes a drive device 6, a flapping wing 10, and a motion conversion mechanism 3. The flapping wing 10 has a rotating shaft at its top and bottom. The output shaft of the drive device 6 is connected to the rotating shaft at one end of the flapping wing 10 via a coupling 9, and the motion conversion mechanism 3 is connected to the rotating shaft at the other end of the flapping wing 10. The flapping wing 10 generates lift during pitching, thereby driving the entire motion module 2 to perform buoyancy motion.

[0049] Figures 4 and 5 show the structural schematic diagram of the motion conversion mechanism 3 of the present invention. The motion conversion mechanism 3 includes a main bevel gear 13, a connecting bracket 14, two Morse taper cylinders 12, and two secondary bevel gears 11. The main bevel gear 13 is fixedly mounted on the rotating shaft at the other end of the flapping wing 10. The two secondary bevel gears 11 are respectively arranged on both sides of the main bevel gear 13 and mesh with the main bevel gear 13. Each secondary bevel gear 11 is coaxially mounted on a Morse taper cylinder 12. The connecting bracket 14 is rotatably connected to the Morse taper cylinder 12 and the rotating shaft at the other end of the flapping wing 10, respectively.

[0050] Since there are two hydraulic energy storage and conversion component brackets 4 and 5, which are symmetrically fixed on the left and right sides of the support body 1 and the composition of both sides is exactly the same, the following discussion will only focus on the hydraulic energy storage and conversion component brackets 4 and 5 on one side.

[0051] Specifically, as shown in Figures 6 and 7, which are schematic diagrams of the hydraulic energy storage and conversion component 5 of the present invention, the hydraulic energy storage and conversion component 5 includes a hydraulic damper 17, a one-way valve 22, a first solenoid valve 23, a high-pressure accumulator 19, a pressure reducing valve 24, a low-pressure accumulator 20, a second solenoid valve 25, and a hydraulic motor 21 connected in sequence. The piezoelectric component is located at the piston rod end of the hydraulic damper 17 and on one side of the drive device 6. It also includes an external oil tank, a piezoelectric component, and a Morse taper. The first solenoid valve 23 and the hydraulic damper 17 are respectively connected to the external oil tank. The rotor of the hydraulic motor 21 is parallel to the piston rod of the hydraulic damper 17 and located on the side close to the drive device 6. The Morse taper is coaxially mounted on the rotor of the hydraulic motor 21 and is coaxially opposite to the Morse taper cylinder 12. The hydraulic buffer 17 is installed on the first plate of the hydraulic energy storage and conversion component bracket 4 and connected to the external oil tank. The high-pressure accumulator 19 and the low-pressure accumulator 20 are installed on the second plate of the hydraulic energy storage and conversion component bracket 4, and the hydraulic motor 21 is installed on the third plate.

[0052] Specifically, as a further optimization of the above solution, a splined sleeve and a splined shaft are provided between the rotor of the hydraulic motor 21 and the Morse taper. The splined sleeve is coaxially fixed at the end of the rotor of the hydraulic motor 21, and the splined shaft passes through and meshes with the splined sleeve. The splined shaft extends into the inner side of the support body 1 along the through hole between the support body 1 and the hydraulic energy storage and conversion component bracket 4. One end of the splined shaft is coaxially fixed to the Morse taper, and the other end is connected to the inside of the splined sleeve through a reset structure. A through hole is opened on the fourth plate of the hydraulic energy storage and conversion component bracket 4, penetrating the support body 1 and the hydraulic energy storage and conversion component bracket 4. A roller bearing is fixedly installed in the through hole, and the roller bearing is fitted and fixed on the splined sleeve.

[0053] Specifically, the reset structure includes multiple springs, with both ends of the springs fixedly connected to the spline shaft and the spline sleeve, respectively.

[0054] During operation, high-pressure oil flows out from the end of the hydraulic cylinder of the hydraulic buffer 17, passes through the high-pressure accumulator 19 and the low-pressure accumulator 20 in sequence, and finally flows into the hydraulic motor 21. The hydraulic buffer 17, the high-pressure accumulator 19, the low-pressure accumulator 20 and the hydraulic motor 21 are connected by a high-pressure hose. A one-way valve 22 and a first solenoid valve 23 are installed at the outlet of the hydraulic buffer 17. The first solenoid valve 23 is located downstream of the one-way valve 22 and has two outlets: one outlet leads to the high-pressure accumulator 19 and the other outlet leads to an external oil tank. A pressure reducing valve 24 is installed between the high-pressure accumulator 19 and the low-pressure accumulator 20. A second solenoid valve 25 is installed at the outlet of the low-pressure accumulator 20. The rotor of the hydraulic motor 21 points towards the support body 1.

[0055] When the motion module 2 touches the piezoelectric component, the hydraulic energy storage and conversion component 5 recovers and stores the kinetic energy of the flapping wing 10 in the form of hydraulic pressure. When the flapping wing 10 moves to the limit position, the hydraulic energy storage and conversion component 5 releases the stored energy and drives the flapping wing 10 to achieve the coupled motion of floating and pitching.

[0056] Specifically, the piezoelectric assembly includes a piezoelectric sensor 18 and a control unit electrically connected to the piezoelectric sensor 18. The piezoelectric sensor 18 is located at the end of the piston rod of the hydraulic buffer 17, and the control unit is electrically connected to the drive device 6. The control unit is also electrically connected to an angle sensor 15 for detecting the rotation angle of the flapping wing 10. The angle sensor 15 is fixed on the second slider 16, and the rotor of the angle sensor 15 is connected to the shaft at the other end of the flapping wing 10. The connecting bracket 14 is connected to the angle sensor 15.

[0057] Specifically, as a further optimization of the above solution, the support body 1 is provided with a first guide structure and a second guide structure to guide the sinking and floating motion of the entire motion module 2. The first guide structure includes a first slider 8 and a first slide rail disposed on the support body 1. The drive device 6 is fixed on the first slider 8, and the first slider 8 is mounted on the first slide rail. The second guide structure includes a second slider 16 and a second slide rail disposed on the support body 1. The second slide rail is parallel to the first slide rail, and the second slider 16 is mounted on the second slide rail. The connecting bracket 14 is connected to the second slider 16.

[0058] Furthermore, the frame 7 is installed above and fixed to the first slider 8. A through hole is opened at the bottom center of the frame 7 and at the corresponding position of the first slider 8. The drive device 6 is installed inside the frame 7, and the rotor of the drive device 6 extends to the bottom of the first slider 8 through the through hole.

[0059] Specifically, as a further optimization of the above scheme, the connecting bracket 14 includes a first ring, a second ring, a third ring, and two cranks. The first ring and the third ring are coaxially arranged, and the central axis of the first ring and the central axis of the second ring are perpendicular. The first ring and the second ring, as well as the second ring and the third ring, are connected by cranks respectively. The second ring is fitted and fixed on the angle sensor 15. The first ring and the second ring are rotatably connected to a Morse taper cylinder 12 by roller bearings.

[0060] Figure 8 shows the curves of floating speed and lift during one cycle of the flapping wing's floating and sinking process with and without buffering in a numerical simulation. It is clear from the figure that with buffering, the lift of the flapping wing 10 is basically synchronized with the floating and sinking speed in one cycle. However, without buffering, the speed stops abruptly at the extreme position, resulting in violent fluctuations in lift and poor synchronization with the speed. Furthermore, the simulation uses a flapping wing 10 with a unit wingspan. The figure with buffering shows that the instantaneous lift can reach approximately 2000 N. In actual engineering, the wingspan of the flapping wing 10 can reach 4 m or even longer, generating even greater lift. In this case, the energy recovered by the hydraulic energy storage and conversion component 5 is even more considerable.

[0061] Figure 9 shows the torque curves of the flapping wing's sinking and floating process with and without buffering during one cycle of numerical simulation. It can be clearly seen from the figure that the maximum torque required by the flapping wing 10 during one cycle is between 1500 N·m and 2000 N·m with buffering, while the maximum pitch torque without buffering reaches 10000 N·m. This indicates that by reasonably setting the buffer during the sinking and floating process of the flapping wing 10, the pitch torque required by the flapping wing 10 can be greatly reduced, thereby reducing the external energy input requirement.

[0062] The principle of the semi-active flapping wing motion device is to drive the flapping wing 10 to rotate to a preset angle in the initial stage, say +75°. After reaching the preset angle, the drive device 6 stops working. At this time, the flapping wing 10 is subjected to force and performs a floating motion. When it moves to the limit position, the drive device 6 needs to rotate the flapping wing 10 to -75° so that it can perform the reverse floating motion. That is, the drive device 6 does not work during the floating process of the flapping wing 10. The angle is only adjusted at the limit position to realize the reciprocating motion of the flapping wing 10.

[0063] The overall control logic and working principle of this invention are as follows:

[0064] Energy storage stage:

[0065] Before operation, the second solenoid valve 25 needs to be closed, the outlet of the first solenoid valve 23 leading to the high-pressure accumulator 19 needs to be opened and the outlet leading to the external oil tank needs to be closed, the pressure reducing valve 24 needs to be opened, and then the oil cylinder of the hydraulic buffer 17 needs to be supplied with oil through the external oil tank until the oil cylinder is full of hydraulic oil.

[0066] Start the drive unit 6 to initialize the pitch angle of the flapping wing 10, assuming it to be +75°, causing the entire motion module 2 to perform a floating motion. During this motion, when the frame 7 contacts the piezoelectric sensor 18 at the piston rod end of the hydraulic buffer 17 on one side, the piezoelectric sensor 18 feeds back the received pressure signal to the control unit, activating the drive unit 6 to drive the flapping wing 10 to perform a pitch motion. During this process, the flapping wing 10 maintains its original floating direction due to lift and inertia, while simultaneously compressing the hydraulic buffer 17 to... High-pressure accumulator 19 and low-pressure accumulator 20 are charged. When flapping wing 10 rotates to -75°, it is already in the reverse floating process. At this time, the drive device 6 stops running, and oil is added to the hydraulic buffer 17 until the piston rod returns to its initial position. Since a one-way valve 22 is installed at the outlet of the hydraulic buffer 17, the high-pressure oil in the high-pressure accumulator 19 will not flow back into the hydraulic buffer 17. When the motion module 2 contacts the piezoelectric sensor 18 on the other side, the above control and motion logic is repeated. When both high-pressure accumulators 19 and low-pressure accumulators 20 reach the maximum pressure standard, if the piston rod is in a compressed state, the first solenoid valve 23 is closed to the outlet of the high-pressure accumulator 19, and the outlet to the external oil tank is opened. When the motion module 2 moves in the reverse direction and no longer applies pressure to the piston rod on that side, the state of the first solenoid valve 23 is restored, and then the kinetic energy recovery and utilization stage begins.

[0067] During the energy storage phase, the rotation of the flapping wing 10 is entirely achieved by the drive unit 6, which contains a servo motor. The servo motor itself can achieve precise angle control through an external control unit. Furthermore, during the energy storage phase, if the accumulator reaches its maximum pressure standard but the piston is still under compression, the hydraulic oil in the cylinder may continue to be compressed into the accumulator, causing overpressure and potentially damaging the instrument.

[0068] Kinetic energy recovery and utilization stage:

[0069] When the high-pressure accumulators 19 and 20 on both sides reach the pressure standard, and the motion module 2 contacts the hydraulic buffer 17 again, the pressure signal is fed back to the control unit through the piezoelectric sensor 18, the power supply to the drive device 6 is turned off, and the second solenoid valve 25 is opened. At this time, the low-pressure accumulator 20 begins to release energy, driving the hydraulic motor 21 to run. The high-pressure accumulator 19 continuously replenishes the low-pressure accumulator 20 with energy to ensure the stable operating pressure of the hydraulic motor 21. At the same time, the oil pressure in the hydraulic buffer 17 continuously increases until the pressure exceeds that of the high-pressure accumulator 19, at which point it begins to replenish the pressure of the high-pressure accumulator 19. After the hydraulic motor 21 is running, the rotor drives the spline 26 to rotate. When the Morse cone 12 on one side of the motion conversion mechanism 3 rises and falls with the motion module 2 until it is fitted with the Morse cone head at the front end of the spline shaft, the secondary bevel gear 11 is driven to rotate by the friction self-locking principle. The secondary bevel gear 11 drives the main bevel gear 13 to rotate, thereby driving the flapping wing 10 and the rotor of the angle sensor 15 to rotate. While rotating, due to the characteristics of the spline 26 itself, the motion module 2 can still perform rising and falling motion, thereby realizing the rising and falling pitch coupling motion.

[0070] During the operation of the entire device in the kinetic energy recovery and utilization phase, the following three situations may occur:

[0071] First, during the process from when the motion module 2 contacts the piston rod to when the motion module 2 sinks to its limit position, the piezoelectric sensor 18 is constantly under pressure. The pitch angle of the flapping wing 10 is continuously monitored by the angle sensor 15. If the pitch angle has reached the preset angle before the motion module 2 sinks to its limit position, the second solenoid valve 25 is closed, the oil supply to the hydraulic motor 21 is stopped, and the drive device 6 is powered on to provide torque to prevent the flapping wing 10 from being passively pitched under the impact of the water flow.

[0072] Second, when the piezoelectric sensor 18 is subjected to pressure, the motion module 2 has already submerged to its limit position, but the pitch angle has not yet reached the preset angle. For example, if it is driven from the initial +75° to +30° by the hydraulic motor 21, the lift direction has not changed, and the submersion motion will stop. A response time is set by the piezoelectric sensor 18. If the signal change of the piezoelectric sensor 18 is less than a certain value within this time, the second solenoid valve 25 is closed, the oil supply to the hydraulic motor 21 is stopped, and the drive device 6 is turned on to drive the flapping wing 10 to pitch for angle compensation.

[0073] Third, when the piezoelectric sensor 18 is not under pressure, the pitch angle of the flapping wing 10 is monitored by the angle sensor 15. For example, if the pitch angle is driven from the initial +75° to -30° by the hydraulic motor 21, although the angle has not reached the standard preset value, it can still passively perform reverse floating and sinking motion. Therefore, at this time, it is only necessary to close the second solenoid valve 25, stop the oil supply to the hydraulic motor 21, and turn on the drive device 6 to provide torque to prevent the flapping wing 10 from being passively pitched under the impact of water flow.

[0074] During all the above processes, when the motion module 2 reverses its floating motion from its extreme position, the spline shaft will rebound to its initial position via the spring inside the spline sleeve. Furthermore, if the high-pressure accumulator 19 reaches its maximum pressure standard, the oil tank outlet of the first solenoid valve 23 is opened, and the outlet of the high-pressure accumulator 19 is closed to prevent overpressure. When the pressure drops to the minimum standard or the piezoelectric sensor 18 is no longer under pressure, the state of the first solenoid valve 23 is restored. Simultaneously, if the angle monitored by the angle sensor 15 remains constant or fluctuates very little for a period of time after transitioning from positive to negative or from negative to positive, oil is replenished to the hydraulic damper 17 until the piston rod returns to its initial position.

[0075] Compared with existing technologies, the energy recovery and utilization system and control method for a semi-active flapping wing power generation device provided by this invention introduces hydraulic energy storage and conversion components during the flapping wing's buoyancy process. This not only allows for the artificial setting of resistance in the buoyancy channel, making the buoyancy motion controlled and synchronized with the lift direction, but also enables the efficient recovery and reuse of buoyancy energy, thereby fully utilizing the energy contribution of the flapping wing's lift, optimizing the buoyancy and pitch coordination of the flapping wing, and effectively improving energy harvesting efficiency. Furthermore, this invention, through a hydraulic energy storage and release mechanism, partially relies on the hydraulic energy storage and conversion components to drive the flapping wing to complete the flapping wing pitch motion or the coupled buoyancy and pitch motion via a motion conversion mechanism. Compared with traditional devices that rely entirely on drive devices, this reduces dependence on drive devices or other active drive devices, effectively reducing the instantaneous pitch torque requirement, reducing external energy input, and improving system efficiency, economy, and operational stability. It is highly practical and worthy of promotion.

[0076] The above-disclosed embodiments are merely preferred embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. An energy recovery and utilization system for a semi-active flapping-wing power generation device, characterized in that, The system includes a motion module and two hydraulic energy storage and conversion components symmetrically arranged on both sides of the motion module. The motion module includes a drive unit, a flapping wing, and a motion conversion mechanism. The output shaft of the drive unit is connected to one end of the flapping wing. The motion conversion mechanism includes a main bevel gear, a connecting bracket, two Morse taper cylinders, and two auxiliary bevel gears. The main bevel gear is fixedly fitted to the rotating shaft at the other end of the flapping wing. The two auxiliary bevel gears are respectively located on both sides of the main bevel gear and mesh with it. Each auxiliary bevel gear is coaxially fitted to a Morse taper cylinder. The connecting bracket is rotatably connected to the Morse taper cylinder and the rotating shaft at the other end of the flapping wing, respectively. The hydraulic energy storage and conversion components include a hydraulic damper, a one-way valve, a first solenoid valve, and a high-pressure accumulator connected in sequence. The device includes a pressure reducing valve, a low-pressure accumulator, a second solenoid valve, and a hydraulic motor. It also includes an external oil tank, a piezoelectric component, and a Morse taper. The first solenoid valve and the hydraulic damper are connected to the external oil tank. The piezoelectric component is located at the end of the piston rod of the hydraulic damper and is positioned on one side of the drive device. The rotor of the hydraulic motor is parallel to the piston rod of the hydraulic damper and is located on the side closer to the drive device. The Morse taper is coaxially mounted on the rotor of the hydraulic motor and is coaxially opposite to the Morse taper. When the drive device touches the piezoelectric component, the hydraulic energy storage and conversion component recovers and stores the kinetic energy of the flapping wing's buoyancy movement in hydraulic form. When the flapping wing moves to its limit position, the hydraulic energy storage and conversion component releases the stored energy, driving the flapping wing to achieve a coupled buoyancy and pitching motion.

2. The energy recovery and utilization system for a semi-active flapping-wing power generation device according to claim 1, characterized in that, A splined sleeve and a splined shaft are provided between the rotor and the Morse taper of the hydraulic motor. The splined sleeve is coaxially fixed at the end of the rotor of the hydraulic motor. The splined shaft passes through the splined sleeve and meshes with the splined sleeve. One end of the splined shaft is coaxially fixed to the Morse taper, and the other end is connected to the inside of the splined sleeve through a reset structure.

3. The energy recovery and utilization system for a semi-active flapping-wing power generation device according to claim 2, characterized in that, The reset structure includes multiple springs, with both ends of the springs fixedly connected to the spline shaft and the spline sleeve, respectively.

4. The energy recovery and utilization system for a semi-active flapping-wing power generation device according to claim 2, characterized in that, The piezoelectric assembly includes a piezoelectric sensor and a control unit electrically connected to the piezoelectric sensor. The piezoelectric sensor is located at the end of the piston rod of the hydraulic damper, and the control unit is electrically connected to the drive device.

5. The energy recovery and utilization system for a semi-active flapping-wing power generation device according to claim 4, characterized in that, It also includes a support body and a first guide structure and a second guide structure that are spaced apart vertically on the support body. The first guide structure includes a first slider and a first slide rail on the support body. A driving device is fixed on the first slider and the first slider is mounted on the first slide rail. The second guide structure includes a second slider and a second slide rail on the support body. The second slide rail is parallel to the first slide rail and the second slider is mounted on the second slide rail. A connecting bracket is connected to the second slider.

6. The energy recovery and utilization system for a semi-active flapping-wing power generation device according to claim 5, characterized in that, The control unit is electrically connected to an angle sensor for detecting the rotation angle of the flapping wing. The angle sensor is fixed on the second slider, and the rotor of the angle sensor is connected to the shaft at the other end of the flapping wing. The connecting bracket is connected to the angle sensor.

7. The energy recovery and utilization system for a semi-active flapping-wing power generation device according to claim 6, characterized in that, The connecting bracket includes a first ring, a second ring, a third ring, and two cranks. The first ring and the third ring are coaxially arranged, and the central axis of the first ring and the central axis of the second ring are perpendicular. The first ring and the second ring, as well as the second ring and the third ring, are connected by cranks. The second ring is fitted and fixed on the angle sensor. The first ring and the second ring are rotatably connected to a Morse taper.

8. The energy recovery and utilization system for a semi-active flapping-wing power generation device according to claim 7, characterized in that, The drive unit includes a servo motor and a frame mounted on the servo motor, and the servo motor and the frame are respectively fixed to the first slider.

9. A control method, implemented based on the system of claim 8, characterized in that, The process includes the following steps: Energy storage stage: Close the second solenoid valve, open the first solenoid valve to the outlet of the high-pressure accumulator and close the outlet switch to the external oil tank, open the pressure reducing valve, and supply oil to the cylinder of the hydraulic buffer through the external oil tank until the cylinder of the hydraulic buffer is full of hydraulic oil; start the drive device, initialize the pitch angle of the flapping wing to the first limit angle, and make the entire motion module perform buoyancy until the frame contacts the piezoelectric sensor on one side. The piezoelectric sensor feeds back the received pressure signal to the control unit, activates the drive device to drive the flapping wing to perform pitching motion, and at the same time the frame compresses the hydraulic buffer to charge the high-pressure accumulator and the low-pressure accumulator. When the pitch angle of the flapping wing is detected to be the second limit angle, stop the operation of the drive device and replenish the hydraulic buffer until the piston rod of the hydraulic buffer returns to the initial position; when the motion module contacts the piezoelectric sensor on the other side, repeat the above steps. The method continues until the high-pressure and low-pressure accumulators on both sides reach the maximum pressure standard; kinetic energy recovery and utilization stage: after the high-pressure and low-pressure accumulators on both sides reach the maximum pressure standard, when the frame contacts the piezoelectric sensor on one side, the piezoelectric sensor feeds back the received pressure signal to the control unit, shuts off the power supply to the drive device, and opens the second solenoid valve. At this time, the low-pressure accumulator begins to release energy, driving the hydraulic motor to run. The high-pressure accumulator continuously replenishes energy to the low-pressure accumulator to ensure the stable operating pressure of the hydraulic motor. At the same time, the oil pressure in the hydraulic buffer continuously increases until the pressure exceeds that of the high-pressure accumulator, at which point it begins to replenish the pressure to the high-pressure accumulator; when the Morse cone and Morse cone head on one side of the motion conversion mechanism are fitted together, the secondary bevel gear is driven to rotate, and the secondary bevel gear drives the main bevel gear to rotate, thereby driving the flapping wing and the angle sensor rotor to rotate, realizing the floating and pitching coupled motion.

10. The control method according to claim 9, characterized in that, During the energy storage phase, when the high-pressure accumulators and low-pressure accumulators on both sides reach the maximum pressure standard and the piston rod of the hydraulic buffer is in a compressed state, the outlet switch of the first solenoid valve to the high-pressure accumulator is closed, and the outlet switch of the first solenoid valve to the external oil tank is opened until the motion module moves in the opposite direction and no longer applies pressure to the piston rod of the hydraulic buffer, then the state of the first solenoid valve is restored.

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