Underwater vehicle and cross-modal motion smooth transition control method

Abstract

The application discloses an underwater vehicle and a cross-mode motion smooth transition control method, and relates to the technical field of robots. The underwater vehicle comprises a shell, a first driving mechanism and a second driving mechanism. The shell comprises a main body and a tail part. The tail part is rotationally arranged at one end of the main body. The first driving mechanism is arranged on the main body and is used for driving the tail part to swing. The second driving mechanism comprises a driving piece, a transmission shaft and a propeller assembly. The driving piece is arranged on the tail part. The propeller assembly is rotationally arranged on the tail part and extends out of the tail part. The transmission shaft is arranged on an output end of the driving piece and is connected with the propeller assembly. The driving piece can drive the propeller assembly to rotate through the transmission shaft. The technical scheme provided by the application can solve the technical problem of poor environmental adaptability of the underwater vehicle.

Description

Technical Field

[0001] This invention relates to the field of robotics, and more particularly to an underwater vehicle and a method for smooth transition control of cross-modal motion. Background Technology

[0002] An underwater vehicle is a device capable of autonomous or remotely controlled navigation underwater and performing specific tasks. It is widely used in various fields such as military, marine science, and underwater engineering. However, traditional underwater vehicles suffer from technical problems such as poor environmental adaptability when navigating underwater.

[0003] Therefore, it is necessary to provide a new method for smooth transition control of underwater vehicles and cross-modal motion to solve the above-mentioned technical problems. Summary of the Invention

[0004] The main objective of this invention is to provide a smooth transition control method for underwater vehicles and cross-modal motion, aiming to solve technical problems such as poor environmental adaptability of underwater vehicles.

[0005] To achieve the above objectives, the present invention provides an underwater vehicle comprising:

[0006] An outer casing, the outer casing comprising a main body and a tail, the tail being rotatably disposed at one end of the main body;

[0007] A first driving mechanism is disposed on the main body and is used to drive the tail to swing.

[0008] The second drive mechanism includes a drive member, a transmission shaft, and a propeller assembly. The drive member is disposed at the tail end, and the propeller assembly is rotatably disposed at the tail end and extends out of the tail end. The transmission shaft is disposed at the output end of the drive member and connected to the propeller assembly. The drive member can drive the propeller assembly to rotate through the transmission shaft.

[0009] In one embodiment, the propeller assembly includes a first propeller and a second propeller, the first propeller being fixedly connected to the drive shaft, and the second propeller being rotatably disposed on the drive shaft; the drive member can drive the first propeller to rotate via the drive shaft, and simultaneously drive the second propeller to rotate in the opposite direction.

[0010] In one embodiment, a first helical gear is fixedly mounted on the drive shaft, a second helical gear is fixedly mounted on the second propeller, and a third helical gear is rotatably mounted on the tail section, wherein the first helical gear and the second helical gear mesh with the third helical gear.

[0011] In one embodiment, there are two third helical gears, which are symmetrically arranged, and both the first and second helical gears mesh with the two third helical gears.

[0012] In one embodiment, the second propeller is located on the side of the first propeller closer to the drive member. The first propeller includes a first hub and a plurality of first blades. The first hub is fixedly disposed on the drive shaft, and each of the first blades is evenly spaced around the first hub. The second propeller includes a second hub and a plurality of second blades. The second hub is rotatably disposed on the drive shaft, and each of the second blades is evenly spaced around the second hub.

[0013] The number of the first blades is greater than the number of the second blades, and the size of the first blades is smaller than the size of the second blades.

[0014] In one embodiment, the tail is rotatably disposed at one end of the main body via a rotating shaft. The first driving mechanism includes a driving body, a first transmission helical gear, and a second transmission helical gear. The driving body is disposed on the main body, the second transmission helical gear is disposed on the rotating shaft, and the first transmission helical gear is disposed at the output end of the driving body and meshes with the second transmission helical gear.

[0015] In one embodiment, the underwater vehicle further includes a tail fin mechanism, which includes a tail fin body, a transmission rod, and a drive unit. The drive unit is disposed at the tail end, the transmission rod is rotatably disposed at the end of the tail end away from the main body and extends along the width direction of the outer shell, the tail fin body is disposed on the transmission rod, the output end of the drive unit is provided with a driving helical gear, the transmission rod is provided with a driven helical gear, and the driven helical gear meshes with the driving helical gear.

[0016] In one embodiment, there are two tail fin mechanisms, which are respectively disposed on both sides of the tail along the width direction of the outer shell, and the second drive mechanism is disposed between the two tail fin mechanisms.

[0017] In one embodiment, the underwater vehicle further includes a pectoral fin mechanism, which includes two drive modules and two pectoral fin bodies. The two drive modules are spaced apart within the main body along the width direction of the outer shell, and the two pectoral fin bodies are symmetrically arranged outside the main body along the width direction of the outer shell. Both pectoral fin bodies pass through the main body and are respectively connected to the output ends of the two drive modules.

[0018] Furthermore, this invention also proposes a cross-modal motion smooth transition control method, applied to the underwater vehicle described above, wherein the cross-modal motion smooth transition control method includes:

[0019] Get the switched duration, where the switched duration refers to the time difference from the start time of switching the driving mode to the current time;

[0020] Based on the already switched duration and the preset total switched time, calculate the modal weights:

[0021] The output ratio of the two driving modes is allocated based on modal weights, and the output of the two first driving mechanisms and the second driving mechanism is controlled based on the output ratio, so that the total driving force of the underwater vehicle reaches the desired value.

[0022] The technical solution of this invention integrates propeller propulsion and biomimetic propulsion, using two different propulsion directions to drive the underwater vehicle, thereby improving its environmental adaptability. In this embodiment, the outer shell consists of a main body and a tail, with the tail rotatably mounted at one end of the main body. A first drive mechanism drives the tail to swing; during underwater navigation, the tail swings via the first drive mechanism, achieving biomimetic propulsion. The second drive mechanism includes a drive component, a transmission shaft, and a propeller assembly. The drive component provides driving force, and the transmission shaft transmits power, transferring the driving force output by the drive component to the propeller assembly. During underwater navigation, the drive component drives the propeller assembly to rotate via the transmission shaft, achieving propeller propulsion. By setting up the first and second drive mechanisms, biomimetic propulsion and propeller propulsion are achieved in the underwater vehicle, allowing it to select different propulsion methods according to its underwater environment, thus improving its environmental adaptability. Specifically, during underwater navigation, underwater vehicles can employ either a first or second drive mechanism depending on the underwater environment to ensure their underwater maneuverability. For example, in complex underwater environments, the underwater vehicle can use a second drive mechanism to improve its maneuverability and resistance to disturbances; while in confined environments or environments requiring high stealth and quietness, the underwater vehicle can use a first drive mechanism to reduce noise and destructive power during underwater operations. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of an underwater vehicle in one embodiment of the present invention;

[0025] Figure 2 A schematic diagram of the structure of the second drive mechanism, the tail fin mechanism and the third helical gear in one embodiment of the present invention;

[0026] Figure 3 A partial structural schematic diagram of an underwater vehicle (excluding the main body) in one embodiment of the present invention;

[0027] Figure 4 A flowchart illustrating a cross-modal motion smooth transition control method in one embodiment of the present invention.

[0028] Explanation of icon numbers:

[0029] 100. Outer shell; 110. Main body; 120. Tail end; 121. Third helical gear; 200. First drive mechanism; 210. Drive body; 211. First transmission helical gear; 212. Second transmission helical gear; 300. Second drive mechanism; 310. Drive shaft; 311. First helical gear; 320. Propeller assembly; 321. First propeller; 3211. First hub; 3212. First blade; 322. Second propeller; 3221. Second helical gear; 3222. Second hub; 3223. Second blade; 330. Drive component; 400. Tail fin mechanism; 410. Tail fin body; 420. Drive rod; 421. Driven helical gear; 430. Drive unit; 431. Active helical gear; 500. Pectoral fin mechanism; 510. Drive module; 520. Pectoral fin body.

[0030] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0033] Furthermore, if the embodiments of the present invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously.

[0034] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0035] Underwater vehicles are devices capable of autonomous or remotely controlled navigation underwater and performing specific tasks. They are widely used in various fields such as military, marine science, and underwater engineering. During actual research and development, researchers have found that traditional underwater vehicles only employ one of two propulsion methods: propeller propulsion and biomimetic propulsion. Since propeller propulsion and biomimetic propulsion each have their advantages and disadvantages, traditional underwater vehicles can only adapt to a single underwater environment, greatly limiting their applicability.

[0036] This invention proposes an underwater vehicle designed to address the technical problem of poor environmental adaptability in underwater vehicles.

[0037] Please see Figures 1 to 3In one embodiment of the present invention, the underwater vehicle includes a shell 100, a first drive mechanism 200, and a second drive mechanism 300. The shell 100 includes a main body 110 and a tail 120, with the tail 120 rotatably disposed at one end of the main body 110. The first drive mechanism 200 is disposed on the main body 110 and is used to drive the tail 120 to swing. The second drive mechanism 300 includes a drive member 330, a transmission shaft 310, and a propeller assembly 320. The drive member 330 is disposed on the tail 120, and the propeller assembly 320 is rotatably disposed on the tail 120 and extends out of the tail 120. The transmission shaft 310 is disposed at the output end of the drive member 330 and connected to the propeller assembly 320. The drive member 330 can drive the propeller assembly 320 to rotate through the transmission shaft 310. In a specific embodiment, the drive member 330 may be a drive motor, a servo motor, etc.

[0038] The technical solution of this invention integrates propeller propulsion and biomimetic propulsion, using two different propulsion directions to drive the underwater vehicle, thereby improving the underwater vehicle's environmental adaptability. In this embodiment, the outer shell 100 consists of a main body 110 and a tail 120, wherein the tail 120 is rotatably disposed at one end of the main body 110. A first drive mechanism 200 is used to drive the tail 120 to swing. During underwater navigation, the tail 120 is driven to swing by the first drive mechanism 200, thereby achieving biomimetic propulsion of the underwater vehicle. A second drive mechanism 300 includes a drive member 330, a transmission shaft 310, and a propeller assembly 320. The drive member 330 is used to provide driving force, and the transmission shaft 310 is used to transmit power, so as to transmit the driving force output by the drive member 330 to the propeller assembly 320. During underwater navigation, the drive member 330 drives the propeller assembly 320 to rotate through the transmission shaft 310, thereby achieving propeller propulsion of the underwater vehicle. By incorporating a first drive mechanism 200 and a second drive mechanism 300, the underwater vehicle achieves both biomimetic propulsion and propeller propulsion. This allows the underwater vehicle to select different propulsion methods based on its underwater environment, enhancing its environmental adaptability. Specifically, during underwater navigation, the underwater vehicle can be driven by either the first drive mechanism 200 or the second drive mechanism 300, depending on the underwater environment, to ensure its underwater mobility. For example, in complex underwater environments, the underwater vehicle can use the second drive mechanism 300 to improve its maneuverability and resistance to disturbances; while in confined environments or environments requiring high concealment and quietness, the underwater vehicle can use the first drive mechanism 200 to reduce noise and destructive force during underwater operations. This underwater vehicle has applications in the fields of underwater robots and underwater navigation equipment.

[0039] Please see Figure 2In one embodiment of the present invention, the propeller assembly 320 includes a first propeller 321 and a second propeller 322. The first propeller 321 is fixedly connected to a drive shaft 310, and the second propeller 322 is rotatably disposed on the drive shaft 310. The drive member 330 can drive the first propeller 321 to rotate through the drive shaft 310, and simultaneously drive the second propeller 322 to rotate in the opposite direction. In this embodiment, by driving the first propeller 321 and the second propeller 322 to rotate in opposite directions by the drive member 330, the stability of the underwater vehicle during underwater movement can be improved, and the propulsion efficiency can be increased. Specifically, when a single propeller pushes the fluid backward, the fluid will apply a reverse torque to the propeller, which will cause the underwater vehicle to rotate in the opposite direction. By setting the first propeller 321 and the second propeller 322 with opposite rotation directions, the reverse torques generated by the two propellers can be canceled out, thereby improving the stability of the underwater vehicle during underwater movement. Furthermore, when a single propeller accelerates fluid backward, the fluid generates a "vortex" in the opposite direction of the propeller's rotation. The kinetic energy contained in this "vortex" is not used to generate thrust, resulting in energy loss. This underwater vehicle, through its first propeller 321 and second propeller 322 rotating in opposite directions, allows the propeller at the tail end to recover the "vortex" generated by the forward propeller propelling the fluid. This significantly reduces energy loss and provides the underwater vehicle with more powerful thrust. In addition, the aforementioned dual-propeller propulsion structure can significantly reduce cavitation, thereby lowering the noise level of the underwater vehicle during underwater operation.

[0040] In one embodiment of the present invention, a first helical gear 311 is fixedly mounted on the drive shaft 310, a second helical gear 3221 is fixedly mounted on the second propeller 322, and a third helical gear 121 is rotatably mounted on the tail section 120. Both the first helical gear 311 and the second helical gear 3221 mesh with the third helical gear 121. In this embodiment, the drive shaft 310 drives the second propeller 322 to rotate in the opposite direction via helical gear transmission. Helical gear transmission has the characteristics of simple structure and good stability. On the one hand, it can simplify the structure of the underwater vehicle and reduce the manufacturing difficulty of the underwater vehicle. On the other hand, it can improve the stability of the drive component 330 when driving the second propeller 322 to rotate in the opposite direction, thereby improving the stability of the underwater vehicle when moving underwater.

[0041] In one embodiment of the present invention, there are two third helical gears 121, which are symmetrically arranged. Both the first helical gear 311 and the second helical gear 3221 mesh with both third helical gears 121. In this embodiment, by employing two symmetrically arranged third helical gears 121 and simultaneously meshing them with the first helical gear 311 and the second helical gear 3221, the stability of the drive unit 330 when driving the second propeller 322 to rotate in the opposite direction can be improved.

[0042] Please see Figure 2 In one embodiment of the present invention, the second propeller 322 is located on the side of the first propeller 321 near the drive member 330. The first propeller 321 includes a first hub 3211 and a plurality of first blades 3212. The first hub 3211 is fixedly disposed on the drive shaft 310, and the first blades 3212 are evenly spaced around the first hub 3211. The second propeller 322 includes a second hub 3222 and a plurality of second blades 3223. The second hub 3222 is rotatably disposed on the drive shaft 310, and the second blades 3223 are evenly spaced around the second hub 3222. The number of first blades 3212 is greater than the number of second blades 3223, and the size of the first blades 3212 is smaller than the size of the second blades 3223. The size of a blade refers to its area. In this embodiment, by designing a greater number of first blades 3212 on the first propeller 321 located at the tail end and a smaller size for the first blades 3212, the propulsion efficiency of the underwater vehicle can be improved. Specifically, in the twin-propeller propulsion structure, the first propeller 321 located at the tail end is in a very complex and highly turbulent flow. By designing a greater number of first blades 3212 on the first propeller 321 and a smaller size for the first blades 3212, it can interact with the turbulent water flow more frequently and smoothly, thereby recovering energy more efficiently and improving the propulsion efficiency of the underwater vehicle.

[0043] Please see Figure 3In one embodiment of the present invention, the tail portion 120 is rotatably mounted on one end of the main body 110 via a rotating shaft. The first driving mechanism 200 includes a driving body 210, a first transmission helical gear 211, and a second transmission helical gear 212. The driving body 210 is mounted on the main body 110, and the second transmission helical gear 212 is mounted on the rotating shaft. The first transmission helical gear 211 is located at the output end of the driving body 210 and meshes with the second transmission helical gear 212. In this embodiment, the driving body 210 drives the tail portion 120 to swing via helical gear transmission. Helical gear transmission has the characteristics of simple structure and good stability, which can reduce the manufacturing difficulty of underwater vehicles and improve the stability of underwater vehicles during underwater movement. In a specific embodiment, the driving body 210 may be a drive motor, a servo motor, etc.

[0044] In this embodiment, the drive body 210 is controlled by an external control system to rotate forward and reverse, thereby driving the tail 120 to swing. Alternatively, the drive body 210 can also drive the tail 120 to swing via a transmission assembly. Specifically, in another embodiment of the present invention, the tail portion 120 is rotatably disposed at one end of the main body 110 via a rotating shaft. The first driving mechanism 200 includes a driving body and a transmission assembly. The transmission assembly includes a first transmission helical gear, a second transmission helical gear, a first transmission block, and a second transmission block. The first transmission helical gear is disposed at the output end of the driving body. Both the first and second transmission blocks are provided with helical gear meshing sections around their circumference. The second transmission helical gear and the first transmission block are provided with rotating shafts spaced apart. The second transmission block is rotatably disposed on the main body 110 and intermittently meshes with the second transmission helical gear. The first and second transmission blocks mesh with the first transmission helical gear at different times (different time meshing means that the first and second transmission blocks do not mesh with the first transmission helical gear at the same time, that is, when the first transmission block meshes with the first transmission helical gear, the second transmission block separates from the first transmission helical gear; when the second transmission block meshes with the first transmission helical gear, the first transmission block separates from the first transmission helical gear). When the first transmission block meshes with the first transmission helical gear, the drive body can drive the tail 120 to swing forward through the first transmission block and the rotating shaft; when the second transmission block meshes with the first transmission helical gear, the drive body 210 can drive the tail to swing in the opposite direction through the second transmission block, the second transmission helical gear and the rotating shaft; thus, the first drive mechanism 200 can drive the tail 120 to swing back and forth through the transmission assembly.

[0045] Please see Figure 2In one embodiment of the present invention, the underwater vehicle further includes a tail fin mechanism 400. The tail fin mechanism 400 includes a tail fin body 410, a transmission rod 420, and a drive unit 430. The drive unit 430 is disposed at the tail 120. The transmission rod 420 is rotatably disposed at the end of the tail 120 away from the main body 110 and extends along the width direction of the outer shell 100. The tail fin body 410 is disposed on the transmission rod 420. The output end of the drive unit 430 is provided with a driving helical gear 431, and the transmission rod 420 is provided with a driven helical gear 421. The driven helical gear 421 meshes with the driving helical gear 431. In this embodiment, the width direction of the outer shell refers to... Figure 1 and Figure 2 The direction indicated by X in the diagram. In this embodiment, the tail fin body 410 is driven to swing by rotating a helical gear, which can improve the stability of the tail fin body 410 when driven by the drive unit 430 and ensure the accurate position of the tail fin body 410 during swing. By driving the tail fin body 410 to swing by the drive unit 430, it can adjust the angle between the tail fin and the water flow during the swing of the tail 120, so that the underwater vehicle can imitate the flexible propulsion effect of fish such as killer whales, thereby improving the underwater vehicle's underwater movement capability. At the same time, through the cooperation of the first drive mechanism 200 and the tail fin mechanism 400, the underwater vehicle can imitate the underwater movement of whales or fish such as killer whales, thereby improving the underwater vehicle's underwater movement capability. In a specific embodiment, the drive unit 430 can be a drive motor, servo motor, etc. In a specific embodiment of the present invention, there are two tail fin mechanisms 400, which are respectively arranged on both sides of the tail 120 along the width direction of the outer shell 100, and the second drive mechanism 300 is arranged between the two tail fin mechanisms 400. In one specific embodiment, to simplify the structure of the underwater vehicle, the transmission rod 420 of the tail fin mechanism 400 is rotatably connected to the third helical gear 121.

[0046] Please see Figure 3 In one embodiment of the present invention, the underwater vehicle further includes a pectoral fin mechanism 500. The pectoral fin mechanism 500 includes two drive modules 510 and two pectoral fin bodies 520. The two drive modules 510 are spaced apart within the main body 110 along the width direction of the outer shell 100. The two pectoral fin bodies 520 are symmetrically arranged outside the main body 110 along the width direction of the outer shell 100. Both pectoral fin bodies 520 pass through the main body 110 and are respectively connected to the output ends of the two drive modules 510. In this embodiment, by driving the two pectoral fin bodies 520 to rotate through the two drive modules 510, the pitch attitude and heading of the underwater vehicle during underwater navigation can be adjusted in real time to improve the underwater vehicle's underwater maneuverability. In a specific embodiment, the drive module 510 may be a drive motor, servo motor, etc.

[0047] Please see Figure 4 , Figure 4A flowchart illustrating a cross-modal motion smooth transition control method in one embodiment of the present invention is provided. The present invention also proposes a cross-modal motion smooth transition control method, applied to the aforementioned underwater vehicle, which includes:

[0048] Step 100: Obtain the switched duration, where the switched duration refers to the time difference between the start time of switching the driving mode and the current time;

[0049] Step 200: Calculate the modal weights based on the already switched duration and the preset total switched time.

[0050] Step 300: Allocate the output ratio of the two driving modes based on modal weights, and control the output of the two first driving mechanisms 200 and the second driving mechanism 300 based on the output ratio, so that the total driving force of the underwater vehicle reaches the desired value.

[0051] In this embodiment, the cross-modal motion smooth transition control method sets time-dependent modal weights and allocates the output ratio of the two driving modes based on these weights, controlling the output of the two driving mechanisms to achieve the desired total driving force of the underwater vehicle, thereby ensuring the stability of the underwater vehicle when switching driving modes. Specifically, the preset total switching time refers to the total time required for the underwater vehicle to switch from one driving mode to another. To ensure smoothness during driving mode switching, the modal weights are generated based on the fifth-order polynomial difference (a trajectory planning method in robot systems) and calculated using a preset calculation formula, which is:

[0052]

[0053] Where t represents the duration of the switch, T trans λ(t) represents the preset total switching time, and λ(t) represents the modal weight.

[0054] When allocating the output ratio of the two driving methods based on modal weights, the output of the two driving mechanisms should satisfy the following:

[0055] μ total (t)=λ(t)μ bio (t)+(1-λ(t))μ pump (t)

[0056] Where, μ total (t) represents the total driving force of the underwater vehicle, μ bio (t) represents the output of the first drive mechanism 200, μ pump λ(t) represents the output of the second drive mechanism 300, and λ(t) represents the modal weight.

[0057] In this embodiment, by utilizing a fifth-order polynomial trajectory planning method, continuous compensation can be performed on pitch angle, yaw angle, and swimming speed to ensure the continuity of position, velocity, and acceleration. During the switching of drive modes, the coordinated action of the pitch controller, yaw controller, and swimming speed controller, combined with real-time pitch and yaw angle information from the attitude sensor, dynamically adjusts the tail fin mechanism 400 and pectoral fin mechanism 500, thereby correcting motion deviations and improving response accuracy when switching drive modes.

[0058] In one specific embodiment, this cross-modal motion smooth transition control method, when switching drive modes, can also predict the future state of the underwater vehicle based on the current total output of the underwater vehicle, and utilize feedforward compensation to optimize control commands, effectively suppressing trajectory deviation and energy waste. The feedforward compensation is calculated by obtaining the feedforward control quantity and the feedforward gain matrix, and its calculation formula is as follows:

[0059] μ ff (t)=K f {χ ref (t+△t)-χ(t+△t)}

[0060] Where, μ ff (t) represents the feedforward control quantity, used to compensate for expected errors or disturbances (such as attitude deviation caused by water flow disturbances during switching); K f χ represents the feedforward gain matrix, used to adjust the strength of the feedforward compensation, and needs to be tuned according to the system's dynamic characteristics (such as response speed and hydrodynamic parameters); ref (t+△t) represents the motion state at time t+△t in the reference trajectory; χ(t+△t) represents the predicted motion state at time t+△t.

[0061] The above description is merely an exemplary embodiment of the present invention and does not limit the scope of protection of the present invention. Any equivalent structural transformations made based on the technical concept of the present invention and the contents of the specification and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present invention.

Claims

1. An underwater vehicle, characterized in that, include: An outer casing, the outer casing comprising a main body and a tail, the tail being rotatably disposed at one end of the main body; A first driving mechanism is disposed on the main body and is used to drive the tail to swing. The second drive mechanism includes a drive member, a transmission shaft, and a propeller assembly. The drive member is disposed at the tail end, and the propeller assembly is rotatably disposed at the tail end and extends out of the tail end. The transmission shaft is disposed at the output end of the drive member and connected to the propeller assembly. The drive member can drive the propeller assembly to rotate through the transmission shaft. The propeller assembly includes a first propeller and a second propeller, wherein the first propeller is fixedly connected to the drive shaft, and the second propeller is rotatably mounted on the drive shaft; The drive unit can drive the first propeller to rotate via the transmission shaft, and simultaneously drive the second propeller to rotate in the opposite direction. The drive shaft is fixedly provided with a first helical gear, the second propeller is fixedly provided with a second helical gear, and the tail is provided with a rotatable third helical gear, wherein the first helical gear and the second helical gear mesh with the third helical gear; The number of the third helical gears is two, and the two third helical gears are symmetrically arranged. Both the first helical gear and the second helical gear mesh with the two third helical gears. The second propeller is located on the side of the first propeller close to the drive member. The first propeller includes a first hub and a plurality of first blades. The first hub is fixedly mounted on the drive shaft, and each of the first blades is evenly spaced around the first hub. The second propeller includes a second hub and a plurality of second blades. The second hub is rotatably mounted on the drive shaft, and each of the second blades is evenly spaced around the second hub. The number of the first blades is greater than the number of the second blades, and the size of the first blades is smaller than the size of the second blades.

2. The underwater vehicle as described in claim 1, characterized in that, The underwater vehicle also includes a tail fin mechanism, which includes a tail fin body, a transmission rod, and a drive unit. The drive unit is located at the tail end, the transmission rod is rotatably located at the end of the tail end away from the main body and extends along the width direction of the outer shell, the tail fin body is located on the transmission rod, the output end of the drive unit is provided with a driving helical gear, the transmission rod is provided with a driven helical gear, and the driven helical gear meshes with the driving helical gear.

3. The underwater vehicle as described in claim 2, characterized in that, The number of tail fin mechanisms is two, and the two tail fin mechanisms are respectively arranged on both sides of the tail along the width direction of the outer shell, and the second drive mechanism is arranged between the two tail fin mechanisms.

4. The underwater vehicle as described in claim 1, characterized in that, The underwater vehicle also includes a pectoral fin mechanism, which includes two drive modules and two pectoral fin bodies. The two drive modules are spaced apart inside the main body along the width direction of the shell, and the two pectoral fin bodies are symmetrically arranged outside the main body along the width direction of the shell. Both pectoral fin bodies pass through the main body and are respectively connected to the output ends of the two drive modules.

5. A cross-modal motion smooth transition control method, applied to an underwater vehicle as described in any one of claims 1 to 4, characterized in that, The cross-modal motion smooth transition control method includes: Get the switched duration, where the switched duration refers to the time difference from the start time of switching the driving mode to the current time; Based on the already switched duration and the preset total switched time, calculate the modal weights: The output ratio of the two driving modes is allocated based on modal weights, and the output of the two first driving mechanisms and the second driving mechanism is controlled based on the output ratio, so that the total driving force of the underwater vehicle reaches the desired value.

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