Multi-fin cooperative propulsion underwater robot and control method thereof

Abstract

The invention relates to the technical field of robots, and discloses a multi-fin cooperative propulsion underwater robot and a control method thereof.The multi-fin cooperative propulsion underwater robot comprises a robot body, a plurality of stay wire sets and a plurality of bionic propulsion units, and each stay wire set comprises two stay wires with opposite rotation directions; the multiple bionic propelling units are symmetrically arranged on the two sides of the robot body in pairs along the central axis of the robot body, and in each stay wire set, the two stay wires with the opposite rotating directions are used for driving the bionic propelling units connected with the stay wires to rotate. By means of the design, under the cooperation of the robot body, the multiple stay wire sets and the multiple bionic propelling units, the underwater robot can achieve complex movement modes such as high-maneuverability movement such as lateral movement, in-situ turning, in-situ rolling and in-situ pitching, and the maneuverability and obstacle avoidance capacity of the underwater robot in a complex three-dimensional space are enhanced.

Description

Technical Field

[0001] The present invention relates to the field of robotics, and in particular to an underwater robot with multiple fins for coordinated propulsion and a control method thereof. Background Art

[0002] As a key carrier for deep-sea exploration, resource development and scientific research, the performance of the underwater robot's power system determines the depth and breadth of mission execution.

[0003] Currently, the mainstream propulsion methods for underwater robots are mainly divided into two categories: propeller propulsion and bionic swing propulsion. Most underwater robots mainly use propeller propulsion as their power system. Although propeller propulsion can provide high speeds, it has significant bottlenecks. For example, the propeller is bulky, has low propulsion efficiency, and has high inertia, which limits control accuracy. The high-speed rotation causes sediment disturbance, which seriously interferes with visual detection and poses a threat to the fragile underwater ecosystem. Its maneuverability and concealment are also difficult to meet the requirements of complex environments.

[0004] Research on biomimetic oscillatory propulsion, particularly small robots based on the oscillatory patterns of fish, focuses on individual biomimetic mechanisms, but exploration of the dynamic characteristics of high-maneuverability and omnidirectional propulsion remains insufficient. Existing multi-fin biomimetic robots mostly achieve three-dimensional motion through the coordinated propulsion of multiple fins. For example, the Chinese patent application number is CN202311131113.0, and the patent name is "An invention patent for a boxfish-like robotic fish with multi-fin coordinated propulsion". It discloses a technical solution for propulsion through two pectoral fins, a dorsal fin, an anal fin and a caudal fin. The robot is mainly driven by the reciprocating swing of the rigid caudal fin, and the other multiple fins are mainly used to coordinate the three-dimensional movement of the fins. However, only one of the five fins of the robot is used for propulsion, which reduces the effective propulsion force and work efficiency of the robot. Secondly, although the robot has three-dimensional motion function through the coordinated propulsion of multiple fins, the gait of the robot is limited, and it cannot achieve high-maneuverability movements such as lateral movement, turning in place, rolling in place and pitching in place. It is difficult to adapt to operational needs in narrow waters and complex terrain, especially it cannot quickly respond to scenarios where it is urgently necessary to change direction in place. Summary of the Invention

[0005] The main purpose of the present invention is to provide an underwater robot with multi-fin coordinated propulsion, aiming to improve the deficiencies of the above-mentioned existing technologies and solve the problem that existing underwater robots lack high maneuverability such as on-the-spot change of direction required in emergency scenarios.

[0006] To achieve the above objectives, the present invention proposes a multi-fin coordinated propulsion underwater robot, comprising:

[0007] Robot body;

[0008] A plurality of pull wire groups, each of the pull wire groups includes two pull wires with opposite rotation directions;

[0009] A plurality of bionic propulsion units, wherein the plurality of bionic propulsion units are symmetrically arranged in pairs on both sides of the robot body along the central axis of the robot body, one end of the plurality of pull wire groups is respectively connected to the plurality of bionic propulsion units in a one-to-one correspondence, and the other ends of the plurality of pull wire groups are all connected to the robot body;

[0010] In each of the pull wire groups, the two pull wires with opposite rotation directions are used to drive the bionic propulsion unit connected thereto to rotate.

[0011] Optionally, the robot body includes:

[0012] First steering gear;

[0013] A driving pulley, connected to the first steering gear, and provided with a plurality of first wire grooves;

[0014] In any one of the pull wire groups, one end of one of the two pull wires with opposite rotation directions is wound in a first wire groove in a forward direction, and the other end is connected to the bionic propulsion unit; one end of the other of the two pull wires with opposite rotation directions is wound in another first wire groove in a reverse direction, and the other end is connected to the bionic propulsion unit.

[0015] Optionally, the bionic propulsion unit includes:

[0016] Second steering gear;

[0017] A driven line wheel, the driven line wheel is mounted on one end of the second steering gear, and the driven line wheel is provided with two second line grooves;

[0018] a bionic fin assembly, the bionic fin assembly being mounted on the other end of the second servo, and the bionic fin assembly being connected to an output shaft of the second servo, the second servo being configured to drive its output shaft to rotate about an axis, thereby driving the bionic fin assembly connected to the output shaft to swing about the axis;

[0019] Wherein, the driven pulley and the driving pulley are connected through a pull wire group. In the pull wire group, one of the two pull wires with opposite rotation directions is connected to a second wire groove, and the other of the two pull wires with opposite rotation directions is connected to another second wire groove.

[0020] Optionally, the bionic fin assembly includes:

[0021] a rigid rod comprising a rod body and a first connector and a second connector provided at one end of the rod body, wherein the first connector is connected to one end of the output shaft, and the second connector is connected to the other end of the output shaft;

[0022] A flexible fin is mounted on the other end of the rod body.

[0023] Optionally, the flexible fin includes:

[0024] first fin surface;

[0025] a second fin surface, the second fin surface being arranged opposite to the first fin surface;

[0026] a fixed end connected to the rod body;

[0027] At the free end opposite to the fixed end, the distance between the first fin surface and the second fin surface gradually decreases from the fixed end toward the free end, so as to form a trend of moving closer to the free end.

[0028] Optionally, the robot body further includes:

[0029] A buoyancy support, wherein a first cover is provided at one end of the buoyancy support and a second cover is provided at the other end of the buoyancy support;

[0030] A sealed cabin, the sealed cabin being installed in the buoyancy support, and the sealed cabin and the first cover being sealedly connected via a sealing ring;

[0031] Among them, a mounting plate is provided in the sealed cabin, a control circuit board and a power supply are provided on the mounting plate, the power supply is electrically connected to the control circuit board, and a control switch is installed on the end face of the sealed cabin, the control switch is electrically connected to the control circuit board.

[0032] Optionally, the outer surface of the first cover body and the outer surface of the second cover body are both spherical surfaces.

[0033] Optionally, a mounting post is provided on the end surface of the driven line wheel facing away from the second steering gear, the mounting post and the driven line wheel are coaxially arranged, a mounting hole is provided on the side wall of the buoyancy support, a bearing is provided in the mounting hole, and the mounting post is inserted into the bearing;

[0034] Wherein, an annular groove is provided on the end of the mounting column, a hole retaining ring is provided in the buoyancy bracket, and the hole retaining ring is sleeved in the annular groove.

[0035] Optionally, the robot body further includes:

[0036] A wire pressing plate, the wire pressing plate being arranged in the buoyancy support;

[0037] The driving pulley is provided with a plurality of annular protrusions arranged at equal intervals and a linear hole group sequentially penetrating the plurality of annular protrusions along the axial direction of the driving pulley, the gap between two adjacent annular protrusions forms the first wire groove, and the linear hole group is provided in plurality, and the plurality of linear hole groups are arranged at equal intervals around the circumference of the driving pulley;

[0038] The linear hole group includes a plurality of wire pulling holes, each of which passes through the corresponding annular protrusion. The wire is wound in the first wire groove and is fixedly connected to the wire pressing plate through the wire pulling hole.

[0039] In addition, the present application also provides a control method for the underwater robot, including:

[0040] When the cable assembly is in a non-driven state, the phase angles of the plurality of bionic propulsion units are adjusted to perform a predetermined plane motion, wherein the predetermined plane motion includes forward, backward, left and right lateral movement, and zero-radius in-situ turning;

[0041] According to the drive control signal, the two cables with opposite rotation directions in each cable group are controlled to be retracted and extended alternately to drive the bionic propulsion unit to rotate around its axis by a predetermined angle;

[0042] The bionic propulsion unit performs a predetermined three-dimensional maneuvering gait, which includes floating on the ground, diving on the ground, rolling on the ground, and pitching on the ground.

[0043] Beneficial effects: The multi-fin collaboratively propelled underwater robot proposed in the present invention includes a robot body, multiple cable groups and multiple bionic propulsion units, each cable group includes two cables with opposite rotation directions; the multiple bionic propulsion units are symmetrically arranged in pairs on both sides of the robot body along the central axis of the robot body, one end of the multiple cable groups is respectively connected to the multiple bionic propulsion units in a one-to-one correspondence, and the other ends of the multiple cable groups are all connected to the robot body; in each cable group, two cables with opposite rotation directions are used to drive the bionic propulsion units connected thereto to rotate. With this design, two cables with opposite rotation directions in multiple cable groups work together to drive the bionic propulsion unit connected to them to rotate by retracting and releasing, and then can coordinate and control the rotation direction and amplitude of the bionic propulsion units in different positions, thereby improving the maneuverability of the robot. With the coordinated cooperation of the robot body, multiple cable groups and multiple bionic propulsion units, the underwater robot can realize complex motion modes, such as lateral movement, on-the-spot turning, on-the-spot rolling and on-the-spot pitching and other high-maneuverability movements, thereby enhancing the maneuverability and obstacle avoidance ability of the underwater robot in complex three-dimensional spaces (such as underwater reef areas and narrow pipes). BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0045] Figure 1 This is a schematic structural diagram of the underwater robot disclosed in this application;

[0046] Figure 2 A schematic diagram of the winding of the underwater robot disclosed in this application;

[0047] Figure 3 This is a schematic diagram of the structure decomposition of the underwater robot disclosed in this application;

[0048] Figure 4 for Figure 3 A local enlarged schematic diagram;

[0049] Figure 5 This is a schematic diagram of the underwater robot disclosed in this application in a standby mode;

[0050] Figure 6 This is a schematic diagram of the underwater robot disclosed in this application moving forward;

[0051] Figure 7 This is a schematic diagram of the underwater robot disclosed in this application moving backward;

[0052] Figure 8 This is a schematic diagram of the underwater robot disclosed in this application moving to the right;

[0053] Figure 9 This is a schematic diagram of the underwater robot disclosed in this application moving to the left;

[0054] Figure 10 This is a schematic diagram of the underwater robot disclosed in this application performing a zero-radius clockwise turn in situ;

[0055] Figure 11 This is a schematic diagram of the underwater robot disclosed in this application performing a zero-radius counterclockwise turn in place;

[0056] Figure 12 This is a schematic diagram of the underwater robot disclosed in this application when floating on the original ground;

[0057] Figure 13 This is a schematic diagram of the underwater robot disclosed in this application when diving underground;

[0058] Figure 14This is a schematic diagram of the underwater robot disclosed in this application during in-situ pitching motion;

[0059] Figure 15 This is a schematic diagram of the underwater robot disclosed in this application during rolling motion in place.

[0060] Description of Figure Numbers:

[0061] 1. Robot body; 11. First servo; 12. Active reel; 121. First wire groove; 122. Annular protrusion; 123. Wire hole; 13. Buoyancy support; 14. Sealed cabin; 15. First cover; 16. Second cover; 17. Bearing; 18. Retaining ring for hole; 2. Bionic propulsion unit; 21. Second servo; 22. Driven reel; 221. Mounting column; 2211. Second wire groove; 2212. Annular slot; 23. Bionic fin assembly; 231. Rigid rod; 2311. First connector; 2312. Second connector; 232. Flexible fin; 2321. First fin surface; 2322. Second fin surface; 2323. Fixed end; 2324. Free end.

[0062] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0064] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0065] In this application, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0066] In addition, the descriptions of "first", "second", etc. in this application are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0067] See also Figures 1 and 2 As shown, an embodiment of the present application provides a multi-fin collaboratively propelled underwater robot, comprising a robot body 1, multiple cable groups (not shown in the figure) and multiple bionic propulsion units 2, each cable group comprising two cables with opposite rotation directions; multiple bionic propulsion units 2 are symmetrically arranged in pairs on both sides of the robot body 1 along the central axis of the robot body 1, one end of the multiple cable groups are respectively connected to the multiple bionic propulsion units 2 in a one-to-one correspondence, and the other ends of the multiple cable groups are all connected to the robot body 1; in each cable group, two cables with opposite rotation directions are used to drive the bionic propulsion unit 2 connected thereto to rotate.

[0068] In one embodiment of the present application, four bionic propulsion units 2 are provided. The four bionic propulsion units 2 are respectively provided on both sides of the robot body 1, and the four bionic propulsion units 2 are symmetrically arranged in pairs along the central axis of the robot body 1. Correspondingly, four pull-wire groups are provided, and the four pull-wire groups correspond to the four bionic propulsion units 2 one by one. The pull-wire groups are composed of two pull-wires with opposite rotation directions. Within the same pull-wire group, when one pull-wire is reeled in, the other pull-wire is simultaneously unreeled. The reeling and unreeling action of the pull-wire drives the bionic propulsion unit 2 connected to the pull-wire to rotate by a predetermined angle.

[0069] Specifically, the predetermined rotation angle of the bionic propulsion unit 2 can be 90° clockwise or 90° counterclockwise. Of course, the predetermined angle can also be 45°, 135°, etc. Those skilled in the art can set the specific rotation angle of the bionic propulsion unit 2 according to actual needs.

[0070] See also Figures 1 and 2As shown, each bionic propulsion unit 2 corresponds to a pull wire group, and each pull wire group includes two pull wires with opposite rotation directions. One end of the two pull wires is wound in the robot body 1 in the forward direction, and the other end is fixed on the corresponding bionic propulsion unit 2. One end of the other of the two pull wires is wound in the robot body 1 in the reverse direction, and the other end is fixed on the corresponding bionic propulsion unit 2. When one pull wire is tightened, the other pull wire is released synchronously and in equal amounts, thereby converting the linear displacement of the pull wire into angular displacement of the bionic propulsion unit 2. In this way, the two pull wires with opposite rotation directions can work together to drive the bionic propulsion unit 2 connected thereto to rotate around the Y direction by retracting and releasing. ， The axis rotates a predetermined angle, whereby multiple cable groups can coordinately control the rotation direction and rotation amplitude of the bionic propulsion units 2 at different positions, thereby improving the maneuverability of the robot. With the coordinated cooperation of the robot body 1, multiple cable groups and multiple bionic propulsion units 2, the underwater robot can realize complex motion modes, such as lateral movement, on-the-spot turning, on-the-spot rolling and on-the-spot pitching and other high-maneuverability movements, thereby enhancing the maneuverability and obstacle avoidance ability of the underwater robot in complex three-dimensional spaces (such as underwater reef areas, narrow pipes, etc.).

[0071] See also Figure 3 and Figure 4 As shown, in one embodiment of the present application, the robot body 1 includes a first servo 11 and a driving pulley 12, the driving pulley 12 is connected to the first servo 11, and a plurality of first wire grooves 121 are provided on the driving pulley 12; in any one pull wire group, one end of one of the two pull wires with opposite rotation directions is wound in a first wire groove 121 in a forward direction, and the other end is connected to the bionic propulsion unit 2; the other one of the two pull wires with opposite rotation directions has one end wound in the other first wire groove 121 in a reverse direction, and the other end is connected to the bionic propulsion unit 2.

[0072] Specifically, in a pull wire group, one end of a pull wire is wound in a forward winding manner and fixed in a first wire groove 121 of the driving wheel 12, and one end of another pull wire is wound in a reverse winding manner and fixed in another first wire groove 121 of the driving wheel 12. The other ends of the two pull wires pass through the robot body 1 respectively and are finally anchored at the driving point of the bionic propulsion unit 2.

[0073] The steering wheel of the first servo 11 is fixedly connected to the driving wheel 12 by fasteners (such as screws, bolts, etc.). When the first servo 11 receives a driving signal and starts to rotate, the first servo 11 drives the driving wheel 12 rigidly connected thereto to rotate synchronously. Since multiple cable groups are respectively wound on the driving wheel 12, as the driving wheel 12 rotates, one of the two cables wound in opposite directions in the cable group is tightened and the other is loosened, so that the two cables in the cable group can be synchronously coupled to realize the retraction and extension action. In this way, the retraction and extension action of the two cables is transmitted to the connection point on the bionic propulsion unit 2. The tightened cable exerts a pulling force on the bionic propulsion unit 2, and the loosened cable reduces its tension, thereby allowing the bionic propulsion unit 2 to rotate in the direction of the tightening cable. Through the coordinated cooperation of the two cables, a force is exerted on the bionic propulsion unit 2 to drive the bionic propulsion unit 2 to rotate around its axis in the direction corresponding to the tightening cable, thereby prompting the bionic propulsion unit 2 to rotate a predetermined angle, thereby improving the maneuverability of the underwater robot.

[0074] See also Figure 1 、 Figure 3 and Figure 4 As shown, in one embodiment of the present application, the bionic propulsion unit 2 includes a second servo 21, a driven reel 22, and a bionic fin assembly 23. The driven reel 22 is mounted on one end of the second servo 21 and is provided with two second wire grooves 2211. The bionic fin assembly 23 is mounted on the other end of the second servo 21 and is connected to the output shaft of the second servo 21. The second servo 21 is configured to drive its output shaft to rotate around an axis to drive the bionic fin assembly 23 connected to the output shaft to swing around the axis. The driven reel 22 and the driving reel 12 are connected by a cable group. In the cable group, one of the two cables with opposite rotation directions is connected to a second wire groove 2211, and the other of the two cables with opposite rotation directions is connected to another second wire groove 2211. A threaded hole is provided on the side of the driven reel 22, and the threaded hole is connected to the second servo 21 by threaded engagement.

[0075] Specifically, by controlling the rotation of the driving pulley 12, the multiple pull lines wound on the driving pulley 12 are connected to the driven pulley 22 through the threading holes, thereby driving the four driven pulleys 22 located outside the robot body 1 to rotate, thereby adjusting the bionic propulsion unit 2 around the Y ， The axis rotates by a predetermined angle.

[0076] When the wire pulley drives the driven wire wheel 22 around Y ， When the axis rotates by a predetermined angle, the bionic fin assembly 23 rotates around the Y axis. ， The axis rotates a predetermined angle. In this application, the bionic fin assembly 23 can be Y ， The second steering gear 21 can also rotate around the Z axis. ，The axis swings to achieve phase change. After the phase change, the bionic fin assembly 23 can swing back and forth to make the underwater robot perform corresponding actions. In this way, the bionic propulsion unit 2 rotates around the Y axis. ， The rotation of the axis is coupled with the phase-changing swing propulsion of the bionic fin assembly 23, which can expand a variety of different collaborative propulsion modes, so that the underwater robot can perform propulsion movements in a variety of different postures, including: turning in place, lateral movement, in-place pitching and in-place rolling, etc., thereby improving the flexibility of the underwater robot.

[0077] In this application, phase change refers to the change in the spatial posture of the four bionic propulsion units 2 when the underwater robot switches to perform an action. For example: when the underwater robot switches from floating to diving, the four bionic propulsion units 2 first need to switch from a vertical downward state to a vertical upward state, and then perform the corresponding action by swinging.

[0078] It is worth mentioning that the underwater robot provided in this application adopts the above-mentioned design, so that the propulsion direction of the bionic fin assembly 23 is parallel to the movement direction of the underwater robot. This design not only improves the propulsion force of the underwater robot, but also improves the propulsion efficiency of the underwater robot.

[0079] The underwater robot provided in this application adopts an underactuated design. The propulsion power source of the underwater robot is only four second servos 21. Only one first servo 11 and a cable group are used to cooperate to realize the spatial posture transformation of the bionic propulsion unit 2. The bionic propulsion unit 2 is controlled by a wire drive to rotate around the Y axis. ， Compared with a fully driven system, axis rotation has advantages in reducing power consumption, cost, weight, etc. In addition, the underwater robot provided by the present application has a simple structure, which reduces the maintenance and repair costs of the robot.

[0080] It should be noted that the sealing and adjustment technologies of the underwater robot provided in this application are conventional technologies and will not be described in detail here.

[0081] See also Figure 3 and Figure 4 As shown, in one embodiment of the present application, the bionic fin assembly 23 includes a rigid rod 231 and a flexible fin 232. The rigid rod 231 includes a rod body (not shown in the figure) and a first connector 2311 and a second connector 2312 arranged at one end of the rod body. The flexible fin 232 is installed on the other end of the rod body. The first connector 2311 is connected to the steering wheel on one end of the output shaft, and the second connector 2312 is connected to the steering wheel on the other end of the output shaft. The flexible fin 232 and the rigid rod 231 are fitted with an interference fit.

[0082] Specifically, steering wheels are installed at both ends of the output shaft, and the first connecting body 2311 and the second connecting body 2312 are fixedly connected to the steering wheels at both ends of the output shaft through fasteners (such as screws, bolts, etc.). In this way, a two-point connection and fixation method is adopted to ensure that the force can be transmitted to the rigid rod 231 through the two steering wheels on the output shaft. Compared with the single-point connection and fixation method, this design reduces the risk of loosening and failure of the fasteners.

[0083] In this application, the forward and reverse rotation of the driven pulley 22 can drive the rigid rod 231 and the flexible fin 232 to rotate forward and reverse accordingly. When the second servo 21 is started, the force is transmitted to the rigid rod 231 through the output shaft of the second servo 21, thereby driving the flexible fin 232 to rotate around the Z direction. ， The axis swings greatly to achieve phase change, and then rotates around the Z ， The axis oscillates in small steps to perform the corresponding movement.

[0084] See also Figure 3 As shown, the flexible fin 232 includes a first fin surface 2321, a second fin surface 2322, a fixed end 2323 connected to the rod body, and a free end 2324 arranged opposite the fixed end 2323. The second fin surface 2322 and the first fin surface 2321 are arranged opposite each other; from the fixed end 2323 to the free end 2324, the distance between the first fin surface 2321 and the second fin surface 2322 gradually decreases, forming a trend of moving closer to the free end 2324. This design can smoothly guide the fluid to flow across the surface of the flexible fin 232 when the flexible fin 232 swings, reducing the tendency of the fluid to separate in the free end 2324 area, suppressing the formation of a wake vortex, and thus reducing the resistance of the flexible fin 232 when it moves in the fluid.

[0085] Specifically, the first fin surface 2321 and the second fin surface 2322 are the upstream surface and the downstream surface respectively during the swinging process of the flexible fin 232, and as the swinging direction of the flexible fin 232 changes, the first fin surface 2321 and the second fin surface 2322 alternately serve as the upstream surface and the downstream surface, the first fin surface 2321 is inclined from the fixed end 2323 to the free end 2324, and the inclination angle of the first fin surface 2321 is 1° to 3°, correspondingly, the second fin surface 2322 is inclined from the fixed end 2323 to the free end 2324, and the inclination angle of the second fin surface 2322 is 1° to 3°. With this design, when the first fin surface 2321 or the second fin surface 2322 serves as the upstream surface, it can promote the fluid to adhere stably to the fin surface and flow, reducing boundary layer separation. When the surface turns into the downstream surface, it can effectively delay the occurrence of large-scale flow separation, maintain laminar or weak turbulent state, and further reduce resistance.

[0086] See also Figure 1 and Figure 2As shown, the robot body 1 also includes a buoyancy support 13 and a sealed cabin 14, a first cover body 15 is provided at one end of the buoyancy support 13, and a second cover body 16 is provided at the other end of the buoyancy support 13; the sealed cabin 14 is installed in the buoyancy support 13, and the sealed cabin 14 and the first cover body 15 are sealed and connected by a sealing ring; wherein, a mounting plate is provided in the sealed cabin 14, a control circuit board and a power supply are provided on the mounting plate, the power supply and the control circuit board are electrically connected, a control switch is installed on the end face of the sealed cabin 14, the control switch and the control circuit board are electrically connected, and the control switch is used to control the on and off of the robot's electrical signal.

[0087] Specifically, the output line of the control circuit board in the present application passes through a hollow bolt to be connected to the first servo 11 and electronic devices such as the depth sensor. Finally, the hollow bolt is sealed underwater with sealant. This design can prevent the control circuit from being affected by liquid, thereby reducing the risk of short circuit in the control circuit.

[0088] In the present application, the threading hole is located on the side wall of the buoyancy support 13. Since a sealed cabin 14 is added inside the present application, even if some liquid enters part of the chamber of the buoyancy support 13 through the threading hole, the control circuit can be ensured not to be affected by the liquid.

[0089] In the present application, the buoyancy support 13 adopts a hollow cylindrical structure, with a first cover body 15 and a second cover body 16 respectively arranged at both ends. The front end face of the buoyancy support 13 and the first cover body 15 are sealed connected by a nitrile rubber O-ring, and the rear end face of the buoyancy support 13 and the second cover body 16 can also be sealed connected by a nitrile rubber O-ring.

[0090] Preferably, the outer surface of the first cover 15 and the outer surface of the second cover 16 are both spherical. This design can reduce the resistance of the underwater robot moving underwater.

[0091] See also Figure 3 and Figure 4 As shown, in one embodiment of the present application, a mounting post 221 is provided on the end face of the driven reel 22 facing away from the second servo 21. The mounting post 221 and the driven reel 22 are coaxially arranged. A mounting hole is provided on the side wall of the buoyancy support 13. A bearing 17 is provided in the mounting hole. The mounting post 221 is inserted into the bearing 17. An annular groove 2212 is provided on the end of the mounting post 221. A hole retaining ring 18 is provided in the buoyancy support 13. The hole retaining ring 18 is sleeved on the annular groove 2212. This design can, on the one hand, ensure the reliability of the connection between the driven reel 22 and the buoyancy support 13, and on the other hand, allow the driven reel 22 to rotate relative to the buoyancy support 13.

[0092] In one embodiment of the present application, the robot body 1 further includes a wire pressing plate, which is arranged in the buoyancy support 13; the driving pulley 12 is provided with a plurality of equally spaced annular protrusions 122 and a linear hole group that sequentially penetrates the plurality of annular protrusions 122 along the axial direction of the driving pulley 12, the gap between two adjacent annular protrusions 122 forms a first wire groove 121, and a plurality of linear hole groups are provided, and the plurality of linear hole groups are arranged at equal intervals around the circumference of the driving pulley 12; the linear hole group includes a plurality of wire pulling holes 123, each of which penetrates the corresponding annular protrusion 122, the wire is wound in the first wire groove 121, and is fixedly connected to the wire pressing plate through the wire pulling hole 123. This design can enhance the installation firmness of the wire.

[0093] For further explanation, the present application also provides a control method for the above-mentioned underwater robot, which is as follows:

[0094] When the cable assembly is in a non-driving state, the phase angles of the multiple bionic propulsion units 2 are adjusted to perform a predetermined plane motion, wherein the predetermined plane motion includes forward, backward, left and right lateral movement, and zero-radius in-situ turning;

[0095] According to the driving control signal, the two oppositely rotating cables in each cable group are controlled to be retracted and extended alternately, so as to drive the bionic propulsion unit 2 to rotate around its axis by a predetermined angle;

[0096] The bionic propulsion unit 2 performs a predetermined three-dimensional maneuvering gait, which includes floating on the ground, diving on the ground, rolling on the ground, and pitching on the ground.

[0097] Specifically, see Figure 5 As shown, when the underwater robot provided by the present application is in standby mode, the four bionic propulsion units 2 are in an expanded state, and at this time, the cable group is in a non-driven state.

[0098] When the cable assembly is disabled, the second servo 21 controls the bionic fin assembly 23 to swing, so that the phase of the bionic fin assembly 23 changes, thereby performing a predetermined planar motion, wherein the predetermined planar motion includes forward, backward, left and right lateral movement, and zero-radius in-situ turning, etc., as follows:

[0099] See also Figure 6 As shown, when the underwater robot moves forward, the two bionic fin assemblies 23 located at the front end of the robot body 1 move closer to each other to form a cone shape, and the two bionic fin assemblies 23 are in an upright state. At this time, the first fin surface 2321 and the second fin surface 2322 on the flexible fin 232 are perpendicular to the horizontal plane, and the two bionic fin assemblies 23 located at the rear end of the robot body 1 are also in an upright state, and the two bionic fin assemblies 23 swing to propel the underwater robot forward.

[0100] See also Figure 7 As shown, when the underwater robot retreats, the two bionic fin assemblies 23 located at the rear end of the robot body 1 move closer to each other to form a cone shape, and the two bionic fin assemblies 23 are in an upright state. At this time, the first fin surface 2321 and the second fin surface 2322 on the flexible fin 232 are perpendicular to the horizontal plane, and the two bionic fin assemblies 23 located at the front end of the robot body 1 are also in an upright state, and the two bionic fin assemblies 23 swing to push the underwater robot backward.

[0101] See also Figure 8 As shown, when the underwater robot moves to the right, the four bionic fin assemblies 23 located on both sides of the robot body 1 are in an upright state. At this time, the first fin surface 2321 and the second fin surface 2322 on the flexible fin 232 are both perpendicular to the horizontal plane, and the two bionic fin assemblies 23 located on the left side of the robot body 1 swing to push the underwater robot to move to the right.

[0102] See also Figure 9 As shown, when the underwater robot moves to the left, the four bionic fin assemblies 23 located on both sides of the robot body 1 are in an upright state. At this time, the first fin surface 2321 and the second fin surface 2322 on the flexible fin 232 are perpendicular to the horizontal plane, and the two bionic fin assemblies 23 located on the right side of the robot body 1 swing to push the underwater robot to move to the left.

[0103] See also Figure 10 As shown, when the underwater robot makes a zero-radius clockwise turn in situ, the four bionic fin assemblies 23 located on both sides of the robot body 1 are in an upright state. At this time, the first fin surface 2321 and the second fin surface 2322 on the flexible fin 232 are perpendicular to the horizontal plane. The bionic fin assembly 23 located in the front row on the left side of the robot body 1 swings, and the bionic fin assembly 23 located in the rear row on the right side of the robot body 1 also swings. The swing of these two bionic fin assemblies 23 drives the underwater robot to make a zero-radius clockwise turn in situ.

[0104] See also Figure 11 As shown, when the underwater robot makes a zero-radius counterclockwise turn in place, the four bionic fin assemblies 23 located on both sides of the robot body 1 are in an upright state. At this time, the first fin surface 2321 and the second fin surface 2322 on the flexible fin 232 are perpendicular to the horizontal plane. The bionic fin assembly 23 located in the left rear row of the robot body 1 swings, and the bionic fin assembly 23 located in the right front row of the robot body 1 also swings. The swing of these two bionic fin assemblies 23 drives the underwater robot to make a zero-radius counterclockwise turn in place.

[0105] According to the driving control signal, the two oppositely rotating cables in each cable group are controlled to alternately retract and extend to drive the bionic propulsion unit 2 to rotate 90 degrees around its axis. At the same time, the four bionic fin assemblies 23 are switched from an upright state to a horizontal state, so that the first fin surface 2321 and the second fin surface 2322 on the flexible fin 232 are parallel to the horizontal plane. Then, the bionic propulsion unit 2 performs a predetermined three-dimensional maneuvering gait, which includes floating on the ground, diving on the ground, rolling on the ground, and pitching on the ground. The details are as follows:

[0106] See also Figure 12 As shown, when the underwater robot floats up on the original surface, the four bionic fin components 23 located on both sides of the robot body 1 are all downward and swing left and right to push the underwater robot to float up on the original surface.

[0107] See also Figure 13 As shown, when the underwater robot dives in situ, the four bionic fin components 23 located on both sides of the robot body 1 are all facing upward and swinging left and right to propel the underwater robot to dive in situ.

[0108] See also Figure 14 As shown, when the underwater robot pitches in place, the two bionic fin components 23 at the front end of the robot body 1 face upward and swing left and right, and the two bionic fin components 23 at the rear end of the robot body 1 face downward and swing left and right to push the underwater robot to pitch in place.

[0109] As shown in Figure 15, when the underwater robot rolls in place, the two bionic fin components 23 located on one side of the robot body 1 face upward and swing left and right, and the two bionic fin components 23 located on the other side of the robot body 1 face downward and swing left and right to push the underwater robot to roll in place.

[0110] In summary, the multi-fin coordinated propulsion underwater robot provided in this application has the following beneficial effects:

[0111] (1) Two oppositely rotating cables in a plurality of cable groups work together to drive the bionic propulsion unit 2 connected thereto to rotate by means of retraction and extension, thereby being able to coordinate and control the rotation direction and amplitude of the bionic propulsion units 2 at different positions, thereby improving the maneuverability of the robot. With the coordinated cooperation of the robot body 1, the plurality of cable groups and the plurality of bionic propulsion units 2, the underwater robot can realize complex motion modes, such as lateral movement, on-the-spot turning, on-the-spot rolling and on-the-spot pitching and other high-maneuverability motions, thereby enhancing the maneuverability and obstacle avoidance capability of the underwater robot in complex three-dimensional spaces (such as underwater reef areas and narrow pipes).

[0112] (2) The four bionic propulsion units 2 are located at the four corners of the robot body 1 and are arranged in a horizontally symmetrical manner. The four bionic propulsion units 2 can realize independent swing control and spatial posture conversion. The four bionic propulsion units 2 work together, and the underwater robot can realize high-maneuverability actions such as straight-line forward and backward movement in any direction, clockwise and counterclockwise turns of any radius, and zero-radius rotation in three-dimensional space, so that the underwater robot can complete navigation and obstacle avoidance as needed to perform complex tasks. In addition, the four bionic fins of the underwater robot can realize arbitrary phase adjustment to improve the robot's propulsion force and propulsion speed, so that the robot can freely switch between cruising or acceleration states as needed.

[0113] (3) Through the cooperation of the first servo 11, the driving reel 12, and the driven reel 22, the flexible fin 232 can be switched from a vertical state to any state such as a horizontal state or an inclined state. By combining the rotational posture of the flexible fin 232 with the phase change of the flexible fin 232, the underwater robot can achieve highly maneuverable three-dimensional movement underwater, including vertical ascent and vertical descent, zero-radius pitch and zero-radius roll, etc., thereby ensuring the high maneuverability of the underwater robot when moving in three-dimensional space. By adjusting the three-dimensional movement posture of the underwater robot in real time, the underwater robot has high flexibility during movement, thereby improving the adaptability of the underwater robot to complex waters.

[0114] (4) The underwater robot provided in this application adopts an under-actuated design. The propulsion power source of the underwater robot is only four second servos 21, and the spatial posture transformation of the flexible fin 232 is achieved only through the cooperation of one first servo 11 and a cable group. Compared with a fully driven system, it has advantages in reducing power consumption, reducing cost, and reducing weight.

[0115] (5) The underwater robot provided in this application integrates the principles of bionics. The rigid rod 231 reproduces the mechanical support characteristics of the fish spine, and the flexible fin 232 simulates the flexible swinging law of the tail fin. This design improves the smoothness of the underwater robot in turning, accelerating and other actions. Secondly, it can also suppress mechanical vibrations, making the operating noise close to the level of natural water flow sound, reducing interference with aquatic organisms, and can be used in special tasks that require low environmental impact and high environmental adaptability, such as underwater archaeology, ecological monitoring, and covert reconnaissance.

[0116] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's description and drawings, or direct / indirect applications in other related technical fields, within the scope of the present invention are included in the patent protection scope of the present invention.

Claims

1. A multi-fin cooperatively propelled underwater robot, characterized in that: include: Robot body; A plurality of pull wire groups, each of the pull wire groups includes two pull wires with opposite rotation directions; A plurality of bionic propulsion units, wherein the plurality of bionic propulsion units are symmetrically arranged in pairs on both sides of the robot body along the central axis of the robot body, one end of the plurality of pull wire groups is respectively connected to the plurality of bionic propulsion units in a one-to-one correspondence, and the other ends of the plurality of pull wire groups are all connected to the robot body; In each of the pull wire groups, the two pull wires with opposite rotation directions are used to drive the bionic propulsion unit connected thereto to rotate.

2. The multi-fin cooperatively propelled underwater robot according to claim 1, characterized in that: The robot body comprises: First steering gear; A driving pulley, connected to the first steering gear, and provided with a plurality of first wire grooves; In any one of the pull wire groups, one end of one of the two pull wires with opposite rotation directions is wound in a first wire groove in a forward direction, and the other end is connected to the bionic propulsion unit; one end of the other of the two pull wires with opposite rotation directions is wound in another first wire groove in a reverse direction, and the other end is connected to the bionic propulsion unit.

3. The multi-fin cooperatively propelled underwater robot according to claim 2, characterized in that: The bionic propulsion unit comprises: Second steering gear; A driven line wheel, the driven line wheel is mounted on one end of the second steering gear, and the driven line wheel is provided with two second line grooves; a bionic fin assembly, the bionic fin assembly being mounted on the other end of the second servo and connected to an output shaft of the second servo, the second servo being configured to drive its output shaft to rotate about an axis, thereby driving the bionic fin assembly connected to the output shaft to swing about the axis; Wherein, the driven pulley and the driving pulley are connected through a pull wire group. In the pull wire group, one of the two pull wires with opposite rotation directions is connected to a second wire groove, and the other of the two pull wires with opposite rotation directions is connected to another second wire groove.

4. The multi-fin cooperatively propelled underwater robot according to claim 3, characterized in that: The bionic fin assembly comprises: a rigid rod comprising a rod body and a first connector and a second connector provided at one end of the rod body, wherein the first connector is connected to one end of the output shaft, and the second connector is connected to the other end of the output shaft; A flexible fin is mounted on the other end of the rod body.

5. The multi-fin cooperatively propelled underwater robot according to claim 4, characterized in that: The flexible fin comprises: first fin surface; a second fin surface, the second fin surface being arranged opposite to the first fin surface; a fixed end connected to the rod body; The free end is arranged opposite to the fixed end, and the distance between the first fin surface and the second fin surface gradually decreases from the fixed end to the free end.

6. The multi-fin cooperatively propelled underwater robot according to claim 5, characterized in that: The robot body also includes: A buoyancy support, wherein a first cover is provided at one end of the buoyancy support and a second cover is provided at the other end of the buoyancy support; A sealed cabin, the sealed cabin being installed in the buoyancy support, and the sealed cabin and the first cover being sealedly connected via a sealing ring; Among them, a mounting plate is provided in the sealed cabin, a control circuit board and a power supply are provided on the mounting plate, the power supply is electrically connected to the control circuit board, and a control switch is installed on the end face of the sealed cabin, the control switch is electrically connected to the control circuit board.

7. The multi-fin cooperatively propelled underwater robot according to claim 6, characterized in that: The outer surface of the first cover body and the outer surface of the second cover body are both spherical surfaces.

8. The multi-fin cooperatively propelled underwater robot according to claim 6, characterized in that: A mounting post is provided on the end surface of the driven line wheel facing away from the second steering gear, the mounting post and the driven line wheel are coaxially arranged, a mounting hole is provided on the side wall of the buoyancy support, a bearing is provided in the mounting hole, and the mounting post is inserted into the bearing; Wherein, an annular groove is provided on the end of the mounting column, a hole retaining ring is provided in the buoyancy bracket, and the hole retaining ring is sleeved in the annular groove.

9. The multi-fin cooperatively propelled underwater robot according to claim 6, characterized in that: The robot body also includes: A wire pressing plate, the wire pressing plate being arranged in the buoyancy support; The driving pulley is provided with a plurality of annular protrusions arranged at equal intervals and a linear hole group sequentially penetrating the plurality of annular protrusions along the axial direction of the driving pulley, the gap between two adjacent annular protrusions forms the first wire groove, and the linear hole group is provided in plurality, and the plurality of linear hole groups are arranged at equal intervals around the circumference of the driving pulley; The linear hole group includes a plurality of wire pulling holes, each of which passes through the corresponding annular protrusion. The wire is wound in the first wire groove and is fixedly connected to the wire pressing plate through the wire pulling hole.

10. The control method of an underwater robot according to any one of claims 1 to 9, characterized in that: include: When the cable assembly is in a non-driven state, the phase angles of the plurality of bionic propulsion units are adjusted to perform a predetermined plane motion, wherein the predetermined plane motion includes forward, backward, left and right lateral movement, and zero-radius in-situ turning; According to the drive control signal, the two cables with opposite rotation directions in each cable group are controlled to be retracted and extended alternately to drive the bionic propulsion unit to rotate around its axis by a predetermined angle; The bionic propulsion unit performs a predetermined three-dimensional maneuvering gait, which includes floating on the ground, diving on the ground, rolling on the ground, and pitching on the ground.

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