A flying fish robot, control system and control method

Abstract

The present invention relates to the field of bionic fish technology, and more specifically, to a flying fish robot, a control system, and a control method, wherein the flying fish robot includes a control module, a pectoral fin motion module, a tail motion module, and a housing, the housing being a fish-shaped structure, the control module being electrically connected to the pectoral fin motion module and the tail motion module, the pectoral fin motion module being movably connected to the middle of the housing, and the pectoral fin motion module including two pectoral fins, the two pectoral fins being located on either side of the housing, the tail motion module comprising a first drive mechanism, a universal joint assembly, and a tail swing assembly connected in sequence, the first drive mechanism being fixedly connected to the housing, the universal joint assembly and the tail swing assembly being movably connected to the housing, the universal joint assembly being configured to convert torque output by the first drive mechanism into force for driving the tail swing assembly to swing back and forth, and the control module being electrically connected to the pectoral fin motion module and the tail motion module. The flying fish robot of the present invention can fully imitate the underwater motion and gliding motion of a flying fish, and has improved motion performance and hovering gliding time.

Description

Technical Field

[0001] The present invention relates to the technical field of bionic fish, and more particularly to a flying fish robot, a control system and a control method. Background Art

[0002] A water-air cross-domain robot is a robotic system with dual underwater and aerial capabilities. It can transition from underwater to air, and vice versa, possessing the ability to maneuver in diverse media environments to adapt to diverse mission requirements. Combining the characteristics of underwater and aerial vehicles, it can perform underwater tasks such as oceanographic surveys, seabed exploration, and underwater rescue. It can also transition from underwater to air for aerial surveillance, search and rescue, and environmental monitoring. Its strong multi-domain adaptability holds enormous promise for broad application.

[0003] Researchers both domestically and internationally have conducted extensive research in the field of water-to-air cross-domain robots. Currently, most robots remain in the laboratory stage, requiring further breakthroughs in theory and functionality. Existing robots capable of water-to-air cross-domain operation are few and far between, and most rely on water jets or propellers for motion. These drive methods suffer from high noise levels, low efficiency, poor flexibility, and control difficulties, making them difficult to adapt to multi-domain missions. To improve the multi-domain adaptability of water-to-air cross-domain robots, an efficient and flexible water-to-air cross-domain robot solution is urgently needed.

[0004] Since ancient times, nature has been the source of numerous technological ideas, engineering principles, and significant human inventions. Numerous creatures in nature are capable of trans-water and trans-air locomotion, including flying fish, dolphins, squid, and manta rays. Among these creatures, flying fish are the most representative of these trans-water and trans-air species, possessing exceptionally efficient and flexible locomotion. Through millennia of natural selection, flying fish have evolved broad pectoral fins that facilitate gliding through the air, as well as tail fins that provide propulsion for leaping and high-speed swimming. During underwater locomotion, a flying fish contracts its pectoral fins and oscillates its tail at a frequency approaching 35Hz, generating substantial propulsion that propels it ever closer to the surface. When its speed approaches 10m / s, it leaps out of the water at a 30-degree angle. The tail fin continues to oscillate at high frequencies, providing continuous propulsion, ultimately leaving the water at a final velocity of approximately 20m / s. When a flying fish reaches the highest point, it will spread its pectoral fins and glide in the air. After gliding a certain distance, the flying fish will begin to descend. When the tail touches the water surface, it will begin to swing at a high frequency to gain power and achieve another sliding movement.

[0005] Because flying fish have excellent ability to move across water and air, they have become the object of imitation for researchers of water-air cross-domain robots. Researchers hope to provide new ideas for the current problems of water-air cross-domain robots by learning from the excellent movement ability of flying fish and applying it to the design of robots.

[0006] A Chinese patent discloses a flying fish-like robot driven by a dielectric elastomer. The robot comprises a robot body and a flying fish-like structure disposed on the robot body. The flying fish-like structure includes drive elements for the tail fin and pectoral fins, and expandable and retractable pectoral fins disposed on either side of the robot body. The invention enables both the expansion and flapping of the pectoral fins. The pectoral fins on either side are designed to be expandable and retractable, and the expansion is driven by a dielectric elastomer intelligent material, which facilitates the robot's movement both in water and in the air. The tail fin disposed at the tail of the robot body primarily provides initial power and angle adjustment for the robot in water, thereby providing greater lift for aerial flight. However, the tail of this flying fish robot is driven by a propeller, and its actual movement differs significantly from that of a flying fish, failing to replicate the natural characteristics of flying fish, such as flexible underwater movement and increased airborne time by wagging their tails. Summary of the Invention

[0007] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a flying fish robot with a higher degree of bionics, flexible underwater movement and prolonged hovering gliding time.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] A flying fish robot is provided, comprising a control module, a pectoral fin motion module, a tail motion module and a shell, wherein the shell is a fish-shaped structure, the control module is electrically connected to the pectoral fin motion module and the tail motion module, the pectoral fin motion module is movably connected to the middle of the shell, and the pectoral fin motion module comprises two pectoral fins, which are respectively arranged on both sides of the shell; the tail motion module comprises a first driving mechanism, a universal joint assembly and a tail swinging assembly which are connected in sequence, the first driving mechanism is fixedly connected to the shell, the universal joint assembly and the tail swinging assembly are movably connected to the shell, the universal joint assembly is used to convert the torque output by the first driving mechanism into a force for driving the tail swinging assembly to swing back and forth, and the control module is electrically connected to the pectoral fin motion module and the tail motion module.

[0010] Through this setting, when the flying fish robot moves, the control module comprehensively controls the movement of the pectoral fin motion module and the tail motion module, thereby realizing different movement modes. The pectoral fin motion module is used to control the opening and closing and pitch of the pectoral fins, thereby realizing underwater pitching movement and gliding in the air. The tail motion module is used to swing to generate propulsion, allowing the flying fish robot to achieve linear motion or turning. The shell plays a role of sealing and waterproofing, and is used to protect the remaining modules. The streamlined design of the shell can also reduce resistance.

[0011] Preferably, the first drive mechanism is a three-phase brushless DC motor. With this arrangement, the first drive mechanism has a fast response speed and a large starting torque, and can provide the torque of the required direction and magnitude of movement in a timely manner under the control of the control module.

[0012] Preferably, the universal joint assembly includes a first rotating member, a second rotating member, a third rotating member, a rotating rod and a fixed frame, one end of the first rotating member is connected to the first driving mechanism, the other end of the first rotating member is connected to the second rotating member, both ends of the third rotating member are rotatably passed through the second rotating member, the middle portion of the rotating rod is passed through the middle of the third rotating member and is fixedly connected, both ends of the rotating rod are rotatably connected to the fixed frame, and the fixed frame is fixedly installed on the shell; the rotating axis of the first rotating member and the rotating axis of the third rotating member are perpendicular to each other, the rotating axis of the third rotating member and the rotating axis of the rotating rod are perpendicular to each other, the angle between the rotating axis of the first rotating member and the rotating axis of the rotating rod is less than 90°, and the rotating axes of the first rotating member, the rotating axes of the third rotating member and the rotating axes of the rotating rod all intersect at one point.

[0013] With this arrangement, when the universal joint is working, the end of the first rotating member connected to the first driving mechanism moves along the first circle, and the end of the first rotating member connected to the second connecting member moves along the second circle. The diameter of the first circle is larger than that of the second circle. The first rotating member moves along a conical trajectory as a whole, and drives the rotating rod to rotate reciprocatingly through the paths of the second rotating member and the third rotating member; the third rotating member is fixedly connected to the rotating rod and can be regarded as a whole. Through kinematic analysis, the conical rotation of the first rotating member can be decomposed into vertical movement and horizontal rotation. There is a relative rotation in the up and down directions between the second rotating member and the third rotating member, and the remaining rotation in the horizontal direction is output to the rotating rod, so that the rotating rod can realize reciprocating rotation.

[0014] Preferably, the tail swing assembly includes a tail cage and a tail plate, one end of the tail cage is fixedly connected to the rotating rod, and the other end of the tail cage is fixedly connected to the tail plate, the tail cage is made of rigid material, and the tail plate is made of elastic material.

[0015] Through this arrangement, the reciprocating torque output from the rotating rod is transmitted to the tail cage, driving the tail cage and the tail plate to swing back and forth, thereby imitating the movement of flying fish.

[0016] Furthermore, the shell includes a head shell and a tail shell. The head shell is made of a rigid material and has a streamlined structure. The pectoral fin motion module is movably connected to the head shell. The tail shell is made of a flexible material and is mounted on the outside of the tail cage. Through this arrangement, the rigid head shell will not deform due to water resistance, which can better protect internal components and reduce resistance. The tail shell can undergo local deformation, but the deformation range will not be too large due to the constraints of the internal tail cage, which helps to reduce resistance. At the same time, during the swinging of the tail motion module, the gaps between the various connection points will change in size. The flexible tail shell can eliminate this dimensional fluctuation, ensuring water resistance and thus increasing the life of the device.

[0017] Preferably, the pectoral fin motion module includes a second drive mechanism, a third drive mechanism, an opening and closing transmission assembly and a pitch transmission assembly. The two pectoral fins are symmetrically arranged on both sides of the shell. The second drive mechanism is connected to the two pectoral fins through the opening and closing transmission assembly, and the third drive mechanism is connected to the two pectoral fins through the pitch transmission assembly.

[0018] Through this setting, the second drive mechanism can control the opening and closing of the pectoral fins through the opening and closing transmission assembly, and the third drive mechanism can adjust the angle of the pectoral fins through the pitch transmission assembly, thereby changing the water flow resistance and direction of the pectoral fins, thereby realizing the pitch adjustment of the flying fish robot.

[0019] Preferably, the opening and closing transmission assembly includes a rope winder, two traction ropes and two elastic members. The rope winder is connected to the first driving mechanism. One end of the two traction ropes is wound around the rope winder, and the other ends of the two traction ropes are respectively fixedly connected to the two pectoral fins; the two pectoral fins are also elastically connected to the shell through two elastic members.

[0020] With this setting, the elastic member has a tendency to bounce the pectoral fins open. When the pectoral fins need to be closed, the rope winder rotates forward, the traction rope is wound around the rope winder, and the traction rope drives the pectoral fins to close; when the pectoral fins need to be opened, the rope winder reverses, the traction rope is detached from the rope winder, and the elastic member bounces the pectoral fins to the open state. The degree of opening of the pectoral fins can be controlled by the length of the rope released by the rope winder.

[0021] Preferably, the pitch transmission assembly includes a driving gear, a driven gear and a rotating shaft, the driving gear is connected to the third driving mechanism, the driven gear is sleeved on the rotating shaft, the driving gear and the driven gear are meshed to form a gear transmission pair, and the two ends of the rotating shaft are respectively fixedly connected to the two pectoral fins.

[0022] With this arrangement, the third driving mechanism drives the rotating shaft to rotate through the driving gear and the driven gear, and the rotation of the rotating shaft drives the pectoral fins to rotate, thereby changing the pitch angle of the pectoral fins.

[0023] Preferably, the pectoral fin includes a flexible membrane and a support rod, and the end of the support rod is rotatably connected to the outside of the shell; one end of the elastic member is connected to the shell, and the other end of the elastic member is connected to the support rod; the end of the traction rope is passed through the support rod, and the flexible membrane is arranged between the support rod and the outside of the shell.

[0024] Preferably, the control module includes a posture sensor, a signal transceiver and a control board. The posture sensor and the signal transceiver are electrically connected to the control board. The control board is also electrically connected to the pectoral fin motion module and the tail motion module respectively.

[0025] Through this setting, the posture sensor can be used to monitor the posture of the flying fish robot itself, thereby providing data support for the PID control of the flying fish robot system, and the signal transceiver is used to communicate with external devices.

[0026] A flying fish robot control system, applicable to any of the flying fish robots described above, is provided with a control board, the control board including a microcontroller, a CAN transceiver, a first interface, a second interface, a wireless communication module, a gyroscope and an acceleration sensor, a USB virtual serial port and a download interface; the microcontroller is provided with a CAN controller, and the microcontroller is communicatively connected with the first drive mechanism via the CAN controller and the CAN transceiver in sequence; the microcontroller is also connected with the gyroscope and the acceleration sensor via an I2C bus; the microcontroller controls the operation of the second drive mechanism via the first interface, and controls the operation of the third drive mechanism via the second interface; the wireless communication module communicates with the microcontroller via the SPI bus to realize wireless control of the robot movement; the USB virtual serial port is used to send motor feedback data to a computer, and the download interface is used to burn a program; the power supply unit is used to supply energy to the first drive mechanism, the second drive mechanism, the third drive mechanism and the control board.

[0027] The motors include, but are not limited to, the drive motors used by the first, second, and third drive mechanisms. This configuration streamlines the control board, integrating functional modules such as servo drive, wireless communication, attitude detection, numerous motor drives, and data transmission. This effectively reduces space usage and contributes to a smaller size for the Flying Fish robot. It also reduces signal transmission distance and resistance, which improves electrical performance, reduces signal interference and transmission loss, and enhances control board security.

[0028] Preferably, the microcontroller further includes a linear voltage regulator, a crystal oscillator circuit, a reset circuit and a breathing light.

[0029] Preferably, the wireless communication module adopts NRF24L01-R, the gyroscope and acceleration sensor adopt MPU6050, the linear voltage regulator adopts AMS1117-3.3, and the crystal oscillator circuit adopts 8MHz.

[0030] Preferably, the microcontroller further includes a timer, and the timer outputs PWM1 and PWM2 signals to the second drive mechanism and the third drive mechanism for rotation, respectively. Through this setting, the microcontroller controls the opening and closing of the pectoral fins and the pitch angle through the timer, and the microcontroller simultaneously uses the speed and angular velocity in the X, Y, and Z directions fed back by the MPU6050 to adjust the amplitude of the opening and closing of the pectoral fins and the pitch, thereby controlling the motion posture of the flying fish robot; the flying fish robot can approach the water surface and jump out at a certain speed and angle with the cooperation of the tail swing assembly and the pectoral fins, and the pectoral fins fully open to obtain lift after entering the air, and the tail swing assembly continues to swing to generate propulsion, and stops swinging after the tail swing assembly is completely out of the water, and finally the flying fish robot glides at a certain speed above the water surface. When the speed of the flying fish robot slows down and is about to fall into the water, the tail swing assembly begins to swing to generate propulsion, and the flying fish robot continues to glide in the air after the speed increases, thereby achieving long-distance gliding motion.

[0031] Preferably, the software system in the microcontroller is configured to include a hardware driver layer, an intermediate layer and a user layer. The hardware driver layer is responsible for driving various peripherals connected to the microcontroller, the intermediate layer adopts the embedded real-time operating system FreeRTOS, and the user layer includes several preset tasks.

[0032] Furthermore, the preset tasks of the user layer include the start task, key mode setting task, PWM control task, protocol parsing task, wireless communication module task and MPU6050 task;

[0033] Furthermore, in the start task, multiple subtasks and kernel objects are created respectively. The kernel objects include but are not limited to event flag groups, message queues, semaphores, etc.

[0034] Furthermore, in the initial state, the Flying Fish robot is set to the pause mode, and the operator can change the working mode of the Flying Fish robot through the wireless communication module task and the key mode setting task;

[0035] The key mode setting task is set as follows: after pressing the button, the controller interrupt will send a semaphore to the key mode setting task. The key mode setting task counts the semaphore. When pressed once within 3 seconds, it enters the PID setting mode, which is used to switch the PID controller of the Flying Fish robot. When the Flying Fish is in the PID setting mode, pressing the button twice within 3 seconds will enter the speed loop PID control; when the Flying Fish is in the PID setting mode, pressing the button 3 times within 3 seconds will enter the speed and position dual-loop PID control. Then the task will set the corresponding event flag, and the Flying Fish will enter the running mode.

[0036] Furthermore, the MPU6050 task is used to obtain the posture data of the flying fish robot, and change the PWM of the second drive mechanism and the third drive mechanism through the posture data of the flying fish. At the same time, the wireless communication module task will encapsulate the posture data into a protocol frame and send it to the remote control device through the wireless communication module. The PC can send the control protocol frame to the microcontroller through the remote control device and the wireless communication module. When the microcontroller receives the protocol frame, the protocol parsing task will parse the received protocol and execute the corresponding functions according to the parsed protocol, including but not limited to setting the position and speed of the first drive mechanism of the flying fish robot; setting the PWM of the second drive mechanism and the third drive servo; setting the working mode of the flying fish robot, etc.

[0037] A flying fish robot motion control method, applied to the above-mentioned flying fish robot control system, includes underwater motion control and gliding motion control, wherein the underwater motion control includes linear control, acceleration / deceleration control, direction change control, and pitch control; the gliding motion control includes the following steps:

[0038] S1, the controller receives the external leap signal and sends a leap command to the tail motion module and the pectoral fin motion module;

[0039] S2: The tail motion module receives a leap command, and the first drive mechanism maintains a certain output frequency, so that the flying fish robot has an initial velocity V1; the pectoral fin motion module receives a leap command, and the pectoral fins partially unfold and form an angle α with the motion direction; the flying fish robot acquires an upward swimming posture;

[0040] S3: After the control module detects that the pectoral fin motion module has left the water surface, it outputs a gliding instruction to the pectoral fin motion module;

[0041] S3, the pectoral fin motion module receives the gliding command, and the pectoral fins are fully deployed;

[0042] S4: After the control module detects that the tail motion module has left the water surface, it sends a gliding command to the tail motion module;

[0043] S5, the tail motion module stops swinging after receiving the gliding command, and the flying fish robot glides in the air at a speed of V2;

[0044] S6: When the control module detects that V2 is less than 1m / s, it sends a working instruction to the tail motion module;

[0045] S7, the tail motion module swings again to generate propulsion force, extending the flying fish robot's hovering time;

[0046] S8. The control module detects that the flying fish robot falls into the water, the gliding motion control ends, and the underwater motion control is entered.

[0047] Through this setting, the flying fish robot can truly restore the movement posture of flying fish in nature, thereby achieving a longer hovering time, which is conducive to improving simulation and concealment.

[0048] Preferably, in step S1, V1>2m / s, 20°<α<30°.

[0049] Preferably, in the gliding motion control, the first driving mechanism is a three-phase brushless DC motor, and is controlled by a double-cascade PID algorithm, specifically:

[0050] The control module obtains the rotation angle deviation of the first drive mechanism 31 as a first error. The first error is processed by the position loop PID algorithm to obtain a position loop output value. The position loop output value is processed by the speed loop PID algorithm to obtain a desired speed. The desired speed is output as the speed value of the first drive mechanism 31. The desired speed is compared with the actual speed of the first drive mechanism to obtain a second error. The second error is then processed by the speed loop PID algorithm to obtain a new desired speed, completing closed-loop control.

[0051] The PID algorithm is as follows:

[0052]

[0053] in:

[0054] u(k): The calculation result of the PID algorithm, that is, the control quantity,

[0055] Kp: The adjustment coefficient of the proportional term, used to adjust the performance of PID,

[0056] Ki: The adjustment coefficient of the integral term, used to adjust the performance of PID,

[0057] Kd: The adjustment coefficient of the differential term, used to adjust the performance of PID.

[0058] e(k): Error, that is, target value - current state value of the controlled object,

[0059] [e(k)-e(k-1)]: Current error - last error.

[0060] Kp, Ki, and Kd are all empirical values ​​that are manually adjusted and controlled. This setup enables closed-loop control of the first drive mechanism using a dual-loop PID algorithm. The control module can continuously adjust the speed of the first drive mechanism based on actual motion results, greatly improving the accuracy of the Flying Fish robot's motion control.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] (1) Through the control module's control of the pectoral fin motion module and the tail motion module, as well as the structural setting of the universal joint assembly in the tail motion module, the flying fish robot can fully reproduce the gliding action of the flying fish, achieving a more realistic bionic effect and a longer hovering time.

[0063] (2) The circuit design is streamlined, and multiple functional units are integrated on the control board, which is conducive to reducing the size of the flying fish robot and reducing the signal transmission distance and resistance, which is conducive to improving electrical performance and improving the safety of the control board.

[0064] (3) The gliding motion is controlled by the PID algorithm, and the gliding posture of the flying fish robot is corrected and adjusted in real time, thereby improving the accuracy of the flying fish robot's bionic motion, which is conducive to further reducing power consumption and improving gliding performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a schematic diagram of the appearance of a flying fish robot according to the present invention;

[0066] Figure 2 This is a schematic diagram of the internal structure of a flying fish robot according to the present invention;

[0067] Figure 3 This is a schematic diagram of the tail motion module structure of a flying fish robot of the present invention;

[0068] Figure 4 This is a schematic structural diagram of a universal joint assembly of a flying fish robot according to the present invention;

[0069] Figure 5 This is a schematic structural diagram of the pectoral fin motion module of a flying fish robot according to the present invention;

[0070] Figure 6 This is a schematic diagram of a flying fish robot control system of the present invention;

[0071] Figure 7 A schematic diagram of the PDI algorithm of a flying fish robot control system of the present invention;

[0072] Figure 8 The figure is a schematic diagram of the software system of a flying fish robot according to the present invention.

[0073] The icon marks are explained as follows:

[0074] 1. Control module; 2. Pectoral fin motion module; 21. Pectoral fin; 211. Flexible membrane; 212. Support rod; 22. Second drive mechanism; 23. Third drive mechanism; 24. Opening and closing transmission assembly; 241. Rope winder; 242. Towing rope; 243. Elastic member; 25. Pitch transmission assembly; 251. Driving gear; 252. Driven gear; 253. Rotating shaft; 3. Tail motion module; 31. First drive mechanism; 32. Universal joint assembly; 321. First rotating member; 322. Second rotating member; 323. Third rotating member; 324. Rotating rod; 325. Fixed frame; 33. Tail swing assembly; 331. Tail cage; 332. Tail plate; 4. Shell; 41. Head shell; 42. Tail shell

[0075] The dotted line a is the rotation axis of the first rotating member; the dotted line b is the rotation axis of the third rotating member; and the dotted line c is the rotation axis of the rotating rod. DETAILED DESCRIPTION

[0076] The present invention is further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only and are schematic, not actual, representations. They should not be construed as limiting this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted from the drawings.

[0077] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0078] Example 1

[0079] like Figures 1 to 5The figure shows an embodiment of a flying fish robot of the present invention, including a control module 1, a pectoral fin motion module 2, a tail motion module 3 and a shell 4, wherein the shell 4 is a fish-shaped structure, the control module 1 is electrically connected to the pectoral fin motion module 2 and the tail motion module 3, the pectoral fin motion module 2 is movably connected to the middle of the shell 4, and the pectoral fin motion module 2 includes two pectoral fins 21, and the two pectoral fins 21 are respectively arranged on both sides of the shell 4; the tail motion module 3 includes a first driving mechanism 31, a universal joint assembly 32 and a tail swing assembly 33 connected in sequence, the first driving mechanism 31 is fixedly connected to the shell 4, the universal joint assembly 32 and the tail swing assembly 33 are movably connected to the shell 4, the universal joint assembly 32 is used to convert the torque output by the first driving mechanism 31 into a force to drive the tail swing assembly 33 to swing back and forth, and the control module 1 is electrically connected to the pectoral fin motion module 2 and the tail motion module 3.

[0080] Through this setting, when the flying fish robot moves, the control module 1 comprehensively controls the movement of the pectoral fin movement module 2 and the tail movement module 3, thereby realizing different movement modes. The pectoral fin movement module 2 is used to control the opening and closing and pitching of the pectoral fins 21, thereby realizing underwater pitching movement and gliding in the air. The tail movement module 3 is used to swing to generate propulsion, so that the flying fish robot can achieve linear motion or turning. The shell 4 plays a role of sealing and waterproofing, and is used to protect the remaining modules. The streamlined design of the shell 4 can also reduce resistance.

[0081] As one embodiment of the present invention, a three-phase brushless DC motor is used as the first drive mechanism 31. With this configuration, the first drive mechanism 31 has a fast response speed and a large starting torque, and can promptly provide the torque of the required direction and magnitude of movement under the control of the control module 1.

[0082] As one embodiment of the present invention, the universal joint assembly 32 includes a first rotating member 321, a second rotating member 322, a third rotating member 323, a rotating rod 324 and a fixed frame 325. One end of the first rotating member 321 is connected to the first driving mechanism 31, and the other end of the first rotating member 321 is connected to the second rotating member 322. Both ends of the third rotating member 323 are rotatably arranged in the second rotating member 322. The middle part of the rotating rod 324 is fixedly arranged in the middle part of the third rotating member 323. Both ends of the rotating rod 324 are rotatably connected to the fixed frame 325, and the fixed frame 325 is fixedly installed on the housing 4; the rotating axis of the first rotating member 321 and the rotating axis of the third rotating member 323 are perpendicular to each other, the rotating axis of the third rotating member 323 and the rotating axis of the rotating rod 324 are perpendicular to each other, the rotating axis of the first rotating member 321 moves along a conical trajectory, and the rotating axes of the first rotating member 321, the third rotating member 323 and the rotating axis of the rotating rod 324 all intersect at a point.

[0083] With this arrangement, when the universal joint is working, the end of the first rotating member 321 connected to the first driving mechanism 31 moves along the first circle, and the end of the first rotating member 321 connected to the second connecting member moves along the second circle. The diameter of the first circle is larger than that of the second circle. The first rotating member 321 moves along a conical trajectory as a whole, and drives the rotating rod 324 to rotate back and forth through the path of the second rotating member 322 and the third rotating member 323; wherein the third rotating member 323 is fixedly connected to the rotating rod 324 and can be regarded as a whole. Through kinematic analysis, the conical rotation of the first rotating member 321 can be decomposed into vertical movement and horizontal rotation. There is a relative rotation in the up and down directions between the second rotating member 322 and the third rotating member 323, and the remaining rotation in the horizontal direction is output to the rotating rod 324, so that the rotating rod 324 can realize reciprocating rotation.

[0084] As one embodiment of the present invention, the tail swing assembly 33 includes a tail cage 331 and a tail plate 332. One end of the tail cage 331 is fixedly connected to the rotating rod 324, and the other end of the tail cage 331 is fixedly connected to the tail plate 332. The tail cage 331 is made of rigid material, and the tail plate 332 is made of elastic material.

[0085] With this arrangement, the reciprocating torque output from the rotating rod 324 is transmitted to the tail cage 331, driving the tail cage 331 and the tail plate 332 to reciprocate, thereby achieving the imitation of the flying fish movement.

[0086] As one embodiment of the present invention, the housing 4 includes a head shell 41 and a tail shell 42. The head shell 41 is made of a rigid material and has a streamlined structure. The pectoral fin motion module 2 is movably connected to the head shell 41. The tail shell 42 is made of a flexible material and is sleeved on the outside of the tail cage 331. Through this arrangement, the rigid head shell 41 will not deform due to water resistance, which can better protect internal components and reduce resistance. The tail shell 42 can undergo local deformation, but the deformation range will not be too large due to the constraints of the internal tail cage 331, which helps reduce resistance. At the same time, during the swinging of the tail motion module 3, the gaps between the various connection points will change in size. The flexible tail shell 42 can eliminate this dimensional fluctuation, ensuring waterproofness and thus increasing the life of the device.

[0087] As an embodiment of the present invention, the pectoral fin motion module 2 includes a second drive mechanism 22, a third drive mechanism 23, an opening and closing transmission assembly 24 and a pitch transmission assembly 25. The two pectoral fins 21 are symmetrically arranged on both sides of the shell 4. The second drive mechanism 22 is connected to the two pectoral fins 21 through the opening and closing transmission assembly 24, and the third drive mechanism 23 is connected to the two pectoral fins 21 through the pitch transmission assembly 25.

[0088] Through this setting, the second drive mechanism 22 can control the opening and closing of the pectoral fins 21 through the opening and closing transmission component 24, and the third drive mechanism 23 can adjust the angle of the pectoral fins 21 through the pitch transmission component 25, thereby changing the water flow resistance and direction of the pectoral fins 21, thereby realizing the pitch adjustment of the flying fish robot.

[0089] As an embodiment of the present invention, the opening and closing transmission assembly 24 includes a rope winder 241, two traction ropes 242 and two elastic members 243. The rope winder 241 is connected to the first driving mechanism 31, one end of the two traction ropes 242 are connected to the rope winder 241, and the other ends of the two traction ropes 242 are respectively fixedly connected to the two pectoral fins 21; the two pectoral fins 21 are also elastically connected to the shell 4 through two elastic members 243.

[0090] Through this arrangement, the elastic member 243 has a tendency to bounce the pectoral fin 21 to open. When the pectoral fin 21 needs to be closed, the rope winder 241 rotates forward, the traction rope 242 is wound around the rope winder 241, and the traction rope 242 drives the pectoral fin 21 to close; when the pectoral fin 21 needs to be opened, the rope winder 241 reverses, the traction rope 242 detaches from the rope winder 241, and the elastic member 243 bounces the pectoral fin 21 to an open state. The degree of opening of the pectoral fin 21 can be controlled by the length of the rope released by the rope winder 241.

[0091] As one embodiment of the present invention, the pitch transmission assembly 25 includes a driving gear 251, a driven gear 252 and a rotating shaft 253. The driving gear 251 is connected to the third driving mechanism 23, and the driven gear 252 is sleeved on the rotating shaft 253. The driving gear 251 and the driven gear 252 are meshed with each other to form a gear transmission pair, and the two ends of the rotating shaft 253 are respectively fixedly connected to the two pectoral fins 21.

[0092] With this arrangement, the third driving mechanism 23 drives the rotating shaft 253 to rotate through the driving gear 251 and the driven gear 252 . The rotation of the rotating shaft 253 drives the pectoral fin 21 to rotate, thereby changing the pitch angle of the pectoral fin 21 .

[0093] As an embodiment of the present invention, the pectoral fin 21 includes a flexible membrane 211 and a support rod 212, and the end of the support rod 212 is rotatably connected to the outside of the shell 4; one end of the elastic member 243 is connected to the shell 4, and the other end of the elastic member 243 is connected to the support rod 212; the end of the traction rope 242 is passed through the support rod 212, and the flexible membrane 211 is arranged between the support rod 212 and the outside of the shell 4.

[0094] Example 2

[0095] like Figures 6 to 8The figure shows an embodiment of a flying fish robot control system of the present invention, which is applied to the flying fish robot of Example 1, including a control board and a power supply unit. The control board includes a microcontroller, a CAN transceiver, a first interface, a second interface, a wireless communication module, a gyroscope and an acceleration sensor, a USB virtual serial port and a download interface; the microcontroller is provided with a CAN controller, and the microcontroller is connected to the first drive mechanism 31 through the CAN controller and the CAN transceiver in turn; the microcontroller is also connected to the gyroscope and the acceleration sensor through the I2C bus; the microcontroller controls the operation of the second drive mechanism 22 through the first interface, and controls the operation of the third drive mechanism 23 through the second interface; the wireless communication module communicates with the microcontroller through the SPI bus to realize wireless control of the robot movement; the USB virtual serial port is used to send the motor feedback data to the computer, and the download interface is used to burn the program; the power supply unit is used to supply energy to the first drive mechanism 31, the second drive mechanism 22, the third drive mechanism 23 and the control board.

[0096] As an embodiment of the present invention, the first driving mechanism is driven by a brushless motor, and the second driving mechanism and the third driving mechanism are both driven by a steering gear.

[0097] Through this setting method, the control board is streamlined. The control board integrates functional modules such as servo drive, wireless communication module, attitude detection, numerous motor drives, and data transmission, which effectively reduces the occupied space and helps to reduce the size of the flying fish robot. In addition, it also reduces the transmission distance and resistance of the signal, which is conducive to improving electrical performance, reducing signal interference and transmission loss, and improving the safety of the control board.

[0098] As an embodiment of the present invention, the software system in the microcontroller is configured to include: a hardware driver layer, an intermediate layer and a user layer. The hardware driver layer is responsible for driving various peripherals connected to the microcontroller, the intermediate layer adopts the embedded real-time operating system FreeRTOS, and the user layer includes several preset tasks.

[0099] As an embodiment of the present invention, the microcontroller further includes a linear voltage regulator, a crystal oscillator circuit, a reset circuit and a breathing light.

[0100] As an embodiment of the present invention, the wireless communication module adopts NRF24L01-R, the gyroscope and acceleration sensor adopt MPU6050, the linear voltage regulator adopts AMS1117-3.3, and the crystal oscillator circuit adopts 8MHz.

[0101] As one embodiment of the present invention, the microcontroller further includes a timer, which outputs PWM1 and PWM2 signals to the second drive mechanism 22 and the third drive mechanism 23 for rotation, respectively. Through this configuration, the microcontroller controls the opening and closing of the pectoral fins 21 and the pitch angle via the timer. The microcontroller also uses the speed and angular velocity in the X, Y, and Z directions fed back by the MPU6050 to adjust the amplitude of the opening and closing of the pectoral fins and the pitch angle, thereby controlling the motion of the flying fish robot. The flying fish robot can approach the water surface and leap out of the water at a certain speed and angle in coordination with the tail swing assembly 33 and the pectoral fins 21. After entering the air, the pectoral fins 21 fully open to generate lift, and the tail swing assembly 33 continues to swing to generate propulsion. After the tail swing assembly 33 is completely out of the water, it stops swinging. Finally, the flying fish robot glides at a certain speed above the water surface. When the flying fish robot slows down and is about to fall into the water, the tail swing assembly 33 begins to swing to generate propulsion, and the flying fish robot continues to glide in the air after increasing its speed, thereby achieving long-distance gliding motion.

[0102] As an embodiment of the present invention, the preset tasks of the user layer include a start task, a key mode setting task, a PWM control task, a protocol parsing task, a wireless communication module task, and an MPU6050 task;

[0103] In the start task, multiple subtasks and kernel objects are created respectively. The kernel objects include but are not limited to event flag groups, message queues, semaphores, etc.

[0104] As an embodiment of the present invention, in the initial state, the Flying Fish robot is set to the pause mode, and the operator can change the working mode of the Flying Fish robot through the wireless communication module task and the key mode setting task;

[0105] The key mode setting task is set as follows: after pressing the button, the controller interrupt will send a semaphore to the key mode setting task. The key mode setting task counts the semaphore. When pressed once within 3 seconds, it enters the PID setting mode, which is used to switch the PID controller of the Flying Fish robot. When the Flying Fish is in the PID setting mode, pressing the button twice within 3 seconds will enter the speed loop PID control; when the Flying Fish is in the PID setting mode, pressing the button 3 times within 3 seconds will enter the speed and position dual-loop PID control. Then the task will set the corresponding event flag, and the Flying Fish will enter the running mode.

[0106] As an embodiment of the present invention, the MPU6050 task is used to obtain the posture data of the flying fish robot, and change the PWM of the second drive mechanism 22 and the third drive mechanism 23 according to the posture data of the flying fish. At the same time, the wireless communication module task will encapsulate the posture data into a protocol frame and send it to the remote control device through the wireless communication module. The PC side can send the control protocol frame to the microcontroller through the remote control device and the wireless communication module. When the microcontroller receives the protocol frame, the protocol parsing task will parse the received protocol and execute corresponding functions according to the parsed protocol, including but not limited to setting the position and speed of the first drive mechanism 31 of the flying fish robot; setting the PWM of the second drive mechanism 22 and the third drive mechanism 23; setting the working mode of the flying fish robot, etc.

[0107] Example 3

[0108] The following is an embodiment of a flying fish robot motion control method of the present invention, which is applied to the flying fish robot control system of Example 2, including underwater motion control and gliding motion control. The pectoral fin motion module 2 includes pectoral fins 21. The underwater motion control includes linear control, acceleration / deceleration control, direction change control and pitch control; the gliding motion control includes the following steps:

[0109] S1, the controller receives the external leap signal and sends a leap instruction to the tail motion module 3 and the pectoral fin motion module 2;

[0110] S2: The tail motion module 3 receives the leap command, and the first drive mechanism 31 maintains a certain output frequency, so that the flying fish robot has an initial velocity V1, V1 = 5m / s; the pectoral fin motion module 2 receives the leap command, and the pectoral fins 21 are partially unfolded and form an angle α with the motion direction, α = 25°; the flying fish robot obtains an upward swimming posture;

[0111] S3, after the control module 1 detects that the pectoral fin motion module 2 leaves the water surface, it outputs a gliding instruction to the pectoral fin motion module 2;

[0112] S3, the pectoral fin motion module 2 receives the gliding instruction, and the pectoral fins 21 are fully unfolded;

[0113] S4, after the control module 1 detects that the tail motion module 3 leaves the water surface, it sends a gliding instruction to the tail motion module 3;

[0114] S5, the tail motion module 3 stops swinging after receiving the gliding command, and the flying fish robot glides in the air at a speed of V2;

[0115] S6: When the control module 1 detects that V2 is less than 1m / s, it sends a working instruction to the tail motion module;

[0116] S7, the tail motion module 3 swings again to generate propulsion force, extending the flying fish robot's hovering time;

[0117] S8. The control module 1 detects that the flying fish robot falls into the water, the gliding motion control ends, and the underwater motion control begins.

[0118] Through this setting, the flying fish robot can truly restore the movement posture of flying fish in nature, thereby achieving a longer hovering time, which is conducive to improving simulation and concealment.

[0119] As an embodiment of the present invention, in the gliding motion control, the first driving mechanism 31 is a three-phase brushless DC motor and is controlled by a double-cascade PID algorithm, specifically:

[0120] The control module obtains the rotation angle deviation of the first drive mechanism 31 as a first error. The first error is processed by the position loop PID algorithm to obtain a position loop output value. The position loop output value is processed by the speed loop PID algorithm to obtain a desired speed. The desired speed is output as the speed value of the first drive mechanism 31. The desired speed is compared with the actual speed of the first drive mechanism to obtain a second error. The second error is then processed by the speed loop PID algorithm to obtain a new desired speed, completing closed-loop control.

[0121] The PID algorithm is as follows:

[0122]

[0123] in:

[0124] u(k): The calculation result of the PID algorithm, that is, the control quantity,

[0125] Kp: The adjustment coefficient of the proportional term, used to adjust the performance of PID,

[0126] Ki: The adjustment coefficient of the integral term, used to adjust the performance of PID,

[0127] Kd: The adjustment coefficient of the differential term, used to adjust the performance of PID.

[0128] e(k): Error, that is, target value - current state value of the controlled object,

[0129] [e(k)-e(k-1)]: Current error - last error.

[0130] Kp, Ki, and Kd are all empirical values ​​and are manually adjusted and controlled. This setup enables closed-loop control of the first drive mechanism 31 using a dual-loop PID algorithm. The control module can continuously adjust the speed of the first drive mechanism 31 based on actual motion results, greatly improving the accuracy of the Flying Fish robot's motion control.

[0131] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A flying fish robot, characterized in that: The invention comprises a control module (1), a pectoral fin motion module (2), a tail motion module (3) and a shell (4), wherein the shell (4) is a fish-shaped structure, the control module (1) is electrically connected to the pectoral fin motion module (2) and the tail motion module (3), and the pectoral fin motion module (2) is movably connected to the middle of the shell (4) during gliding in the air, and the pectoral fin motion module (2) comprises two pectoral fins (21), and the two pectoral fins (21) are respectively arranged on both sides of the shell (4); the tail motion module (3) comprises a plurality of pectoral fins (21) and a plurality of pectoral fins (21) arranged on both sides of the shell (4); the pectoral fins (21) are ... A first drive mechanism (31), a universal joint assembly (32), and a tail swing assembly (33) are connected, wherein the first drive mechanism (31) is fixedly connected to the housing (4), the universal joint assembly (32) and the tail swing assembly (33) are both movably connected to the housing (4), the universal joint assembly (32) is used to convert the torque output by the first drive mechanism (31) into a force for driving the tail swing assembly (33) to swing back and forth, and the control module (1) is electrically connected to the pectoral fin motion module (2) and the tail motion module (3); The pectoral fin motion module is used to control the opening and closing and pitching of the pectoral fins, thereby achieving underwater pitching motion; The universal joint assembly (32) includes a first rotating member (321), a second rotating member (322), a third rotating member (323), a rotating rod (324) and a fixed frame (325), wherein one end of the first rotating member (321) is connected to the first driving mechanism (31), and the other end of the first rotating member (321) is connected to the second rotating member (322). Both ends of the third rotating member (323) are rotatably inserted into the second rotating member (322), and the middle portion of the rotating rod (324) is inserted into the middle portion of the third rotating member (323) and is fixedly connected. The rotating rod (324) Both ends are rotatably connected to a fixing frame (325), and the fixing frame (325) is fixedly mounted on the housing (4); the rotation axis of the first rotating member (321) and the rotation axis of the third rotating member (323) are perpendicular to each other, the rotation axis of the third rotating member (323) and the rotation axis of the rotating rod (324) are perpendicular to each other, the angle between the rotation axis of the first rotating member (321) and the rotation axis of the rotating rod (324) is less than 90°, and the rotation axes of the first rotating member (321), the third rotating member (323) and the rotating rod (324) all intersect at one point; The tail swing assembly (33) comprises a tail cage (331) and a tail plate (332), one end of the tail cage (331) is fixedly connected to the rotating rod (324), and the other end of the tail cage (331) is fixedly connected to the tail plate (332), the tail cage (331) is made of a rigid material, and the tail plate (332) is made of an elastic material.

2. The flying fish robot according to claim 1, characterized in that: The pectoral fin motion module (2) further comprises a second drive mechanism (22), a third drive mechanism (23), an opening and closing transmission assembly (24) and a pitch transmission assembly (25); the two pectoral fins (21) are symmetrically arranged on both sides of the shell (4); the second drive mechanism (22) is connected to the two pectoral fins (21) respectively through the opening and closing transmission assembly (24); and the third drive mechanism (23) is connected to the two pectoral fins (21) respectively through the pitch transmission assembly (25).

3. The flying fish robot according to claim 2, characterized in that: The opening and closing transmission assembly (24) includes a rope winder (241), two traction ropes (242) and two elastic members (243). The rope winder (241) is connected to the second driving mechanism (22). One end of each of the two traction ropes (242) is wound around the rope winder (241), and the other ends of the two traction ropes (242) are fixedly connected to the two pectoral fins (21). The two pectoral fins (21) are also elastically connected to the housing (4) via the two elastic members (243).

4. The flying fish robot according to claim 2, characterized in that: The pitch transmission assembly (25) comprises a driving gear (251), a driven gear (252) and a rotating shaft (253); the driving gear (251) is connected to the third driving mechanism (23); the driven gear (252) is sleeved on the rotating shaft (253); the driving gear (251) and the driven gear (252) are meshed to form a gear transmission pair; and the two ends of the rotating shaft (253) are respectively fixedly connected to the two pectoral fins (21).

5. A control method, characterized in that: A flying fish robot according to any one of claims 2 to 4, comprising underwater motion control and gliding motion control, wherein the underwater motion control includes linear control, acceleration / deceleration control, direction change control, and pitch control; and the gliding motion control includes the following steps: S1, the control module (1) receives the external leap signal and sends a leap instruction to the tail motion module (3) and the pectoral fin motion module (2); S2, the tail motion module (3) receives a leap instruction, and the first drive mechanism (31) maintains a certain output frequency, so that the flying fish robot has an initial velocity V1; the pectoral fin motion module (2) receives a leap instruction, and the pectoral fins (21) are partially unfolded and form an angle α with the motion direction; the flying fish robot obtains an upward swimming posture; S3, after the control module (1) detects that the pectoral fin motion module (2) leaves the water surface, it outputs a gliding instruction to the pectoral fin motion module (2); S3, the pectoral fin motion module (2) receives the gliding instruction, and the pectoral fins (21) are fully unfolded; S4, after the control module (1) detects that the tail motion module (3) leaves the water surface, it sends a gliding instruction to the tail motion module (3); S5, the tail motion module (3) stops swinging after receiving the gliding command, and the flying fish robot glides in the air at a speed of V2; S6, when the control module (1) detects that V2 < 1m / s, it sends a working instruction to the tail motion module (3); S7, the tail motion module (3) swings again to generate propulsion force, extending the flying fish robot's hovering time; S8. The control module (1) detects that the flying fish robot falls into the water, the gliding motion control ends, and the underwater motion control begins.

6. A control method according to claim 5, characterized in that: The first driving mechanism (31) is a three-phase brushless DC motor and is controlled by a double-cascade PID algorithm, specifically: The control module obtains the rotation angle deviation of the first drive mechanism (31) as a first error, obtains a position loop output value by a position loop PID algorithm, obtains a desired speed by a speed loop PID algorithm, outputs the desired speed as the speed value of the first drive mechanism (31), and compares the desired speed with the actual speed of the first drive mechanism to obtain a second error, obtains a new desired speed by the speed loop PID algorithm, and completes closed-loop control; The PID algorithm is as follows: in: u(k): The calculation result of the PID algorithm, that is, the control quantity, Kp: The adjustment coefficient of the proportional term, used to adjust the performance of PID, Ki: The adjustment coefficient of the integral term, used to adjust the performance of PID, Kd: The adjustment coefficient of the differential term, used to adjust the performance of PID. e(k): Error, that is, target value - current state value of the controlled object, [e(k) - e(k-1)]: Current error - last error.

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