Underwater unmanned vehicle bottom staying system and control method

Abstract

According to the underwater unmanned vehicle bottom staying system and the control method, bottom staying of the unmanned vehicle can be achieved, underwater static position keeping is achieved, the requirements of scenes such as load laying and recovery for platform attitude stability are met, floating and staying state switching can be conducted at any time, and the underwater unmanned vehicle bottom staying system and the control method have the advantages of being simple and reliable to use, high in practicability and the like. The modularization degree is high, and the requirement for an aircraft platform is low. The bottom staying system comprises a recoverable seat bottom unit, a buoyancy adjusting unit and a bottom staying control unit. The recoverable base unit is arranged at the bottom of the aircraft, and provides a supporting point for seabed contact for the aircraft when staying at the bottom; the recoverable base unit can stretch out and draw back relative to the aircraft to achieve the retracting state and the stretching state. The buoyancy adjusting unit is arranged on the aircraft and provides positive buoyancy and negative buoyancy for the aircraft through buoyancy adjustment, so that the aircraft floats or dives; and the recoverable base unit and the buoyancy adjusting unit are controlled by the bottom-staying control unit.

Description

Technical Field

[0001] The invention relates to a bottom-stationing system, in particular to a bottom-stationing system for an underwater unmanned vehicle, and belongs to the technical field of underwater unmanned vehicles. Background Art

[0002] Underwater unmanned vehicles are widely used in various fields such as underwater survey, search and rescue, and salvage. Among them, large (large and ultra-large) unmanned submersibles, due to their many advantages such as long range, great depth, ultra-long self-sustaining power, and strong load-carrying capacity, are extremely important in the military as a means of force multiplication.

[0003] The role of large unmanned underwater vehicles is mainly to serve as unmanned combat platforms, performing tasks such as payload loading, delivery and recovery, data collection and distribution, and communication relay. In the operation process, when data collection or payload deployment and recovery is involved, the platform needs to be on standby or in a regional standby mode.

[0004] In order to meet functional requirements while taking energy economy into consideration, common technical means include: (1) adopting low-speed power control to hover in place; (2) low-speed maneuvering and towing in a small area; (3) anchoring and grabbing the bottom through the anchoring device to achieve staying in place.

[0005] However, the low-speed power control method of hovering in place requires the UUV to be equipped with a power control system. The control system is relatively complex and difficult to control, especially in complex environments with external surges and currents. It is difficult to independently control the attitude in a stable manner. In addition, the control system is generally composed of multiple thrusters, which consume a lot of energy when working continuously, and the energy economy is poor when working for a long time.

[0006] The low-speed maneuvering swimming method in a small area requires that the device must be in motion all the time and cannot meet the needs of staying at a fixed point. The propellers and control equipment also need to continuously consume energy during the movement.

[0007] When using an anchoring device to drop anchor and catch the bottom, the first thing to consider is the anchoring force. To ensure that the submersible is anchored to resist the impact of the surge and does not move, the anchor needs to be of a certain weight, which will sacrifice the load-bearing capacity of the vehicle itself; secondly, the problem of anchor recovery needs to be considered. An overly heavy anchor increases the burden on the recovery system. The recovery device will occupy a large volume, weight, power consumption, etc. The vehicle will also need to provide a large positive buoyancy during recovery, which greatly increases the difficulty of the overall system design of the vehicle. In addition, in the single-point anchor state, the vehicle will swing under the action of the surge, and the absolute stability of the attitude cannot be guaranteed. It cannot adapt to work scenarios that require stability of the attitude. The use of multi-point anchoring will further increase the complexity of the system and reduce the reliability of the system. It is not economical in terms of difficulty and cost. Summary of the invention

[0008] In view of this, the present invention provides an underwater unmanned vehicle bottom parking system, which can realize the bottom parking of the unmanned vehicle and maintain the static position on the bottom of the water, meet the requirements of the platform attitude stability in scenarios such as load deployment and recovery, and can switch between floating and stationary states at any time. It has the characteristics of simple and reliable use, high degree of modularization, and low requirements for the vehicle platform.

[0009] The technical solution of the present invention is: a bottom-stationing system for underwater unmanned vehicles, comprising: a recoverable bottom-stationing unit, a buoyancy regulating unit and a bottom-stationing control unit;

[0010] The recyclable bottom unit is arranged at the bottom of the vehicle, and provides a fulcrum for the vehicle to contact the seabed when the vehicle is stationary; the recyclable bottom unit can be extended and retracted relative to the vehicle, and can be in two states: retracted and extended;

[0011] The buoyancy adjustment unit is arranged on the aircraft, and provides positive or negative buoyancy to the aircraft through buoyancy adjustment, so that the aircraft floats up or dives;

[0012] The recoverable base unit and the buoyancy regulating unit are controlled by the bottom-staying control unit.

[0013] As a preferred embodiment of the present invention, the recyclable base unit comprises: telescopic legs, a buffer foot and a locking mechanism;

[0014] The fixed end of the telescopic leg is connected to the aircraft, and a buffer foot is provided at the end of the telescopic leg; when the aircraft is in a navigation state, the telescopic leg is retracted inside the aircraft, and the buffer foot at the end thereof is in the same shape as the aircraft shape; when the recyclable base unit is needed to provide support for the aircraft, the telescopic leg is extended;

[0015] The locking mechanism is used to limit and lock the telescopic legs in both retracted and extended states.

[0016] As a preferred embodiment of the present invention, four sets of recoverable base units are divided into two groups and installed on both sides of the buoyancy center of the vehicle along the bow and stern directions, and two sets of recoverable base units in each group are symmetrically arranged along the axis of the vehicle.

[0017] As a preferred embodiment of the present invention, two symmetrically arranged sets of recoverable base units are extended outwardly at a set angle relative to the aircraft.

[0018] As a preferred embodiment of the present invention, the buoyancy regulating unit comprises: a water tank, a liquid level sensor arranged in the water tank, and a water inlet and outlet pump connected to the water tank;

[0019] The liquid level sensor monitors the water level in the water tank in real time and sends the water level to the bottom-station control unit, and the water inlet and outlet pumps are controlled by the bottom-station control unit.

[0020] As a preferred embodiment of the present invention, two sets of buoyancy regulating units are respectively installed in the fore and aft directions on both sides of the buoyancy center of the vehicle.

[0021] As a preferred embodiment of the present invention, the bottom-stationed control unit can interact with the integrated control system of the aircraft to collect the operation information of the aircraft, including but not limited to the attitude information, altitude information and depth information of the aircraft.

[0022] In addition, the present invention provides a method for controlling an underwater unmanned vehicle to stay at the bottom. The control process of the underwater unmanned vehicle staying at the bottom by the above-mentioned underwater unmanned vehicle staying system is as follows:

[0023] S11: the vehicle arrives at an underwater target position, where the vehicle is ready to start unpowered diving;

[0024] When the vehicle meets the bottom-stationing condition for unpowered diving, a bottom-stationing instruction is sent to the bottom-stationing control unit;

[0025] S12: After receiving the bottom seat instruction, the bottom station control unit controls the recyclable bottom seat unit to extend;

[0026] S13: the bottom-station control unit controls the buoyancy regulating unit to start working, providing negative buoyancy for the aircraft, so that the aircraft dives without power under the action of the negative buoyancy;

[0027] During the diving process of the aircraft, the bottom-station control unit controls the buoyancy adjustment unit according to the state of the aircraft during the current descent process, so that the attitude and descent speed of the aircraft are stable during the diving process;

[0028] S14: When the bottom-station control unit determines that the recoverable bottom seat unit has touched the bottom, the buoyancy adjustment unit continues to inject water into the water tank to a set value; then the entire bottom-station process is completed, and the vehicle enters a bottom-station state.

[0029] As a preferred embodiment of the present invention, the process of controlling the aircraft to float upward is as follows:

[0030] S21: After receiving the floating instruction, the bottom-station control unit enters the working state from the standby state;

[0031] S22: the bottom-station control unit controls the buoyancy adjustment unit to provide positive buoyancy for the aircraft, and determines the lift-off state of the aircraft: if it is determined that the aircraft has lifted off the ground, the next step is entered; otherwise, the buoyancy adjustment is continued until it is determined that the aircraft has lifted off the ground;

[0032] S23: the bottom-station control unit controls the buoyancy adjustment unit to perform attitude control on the aircraft until the aircraft state becomes stable and the buoyancy adjustment amount finally reaches the target setting value;

[0033] S24: The recyclable base unit is retracted and the floating process is completed.

[0034] Beneficial effects:

[0035] (1) The present invention adjusts the buoyancy of the vehicle through a buoyancy adjustment unit, so that the vehicle can achieve unpowered diving. During the bottoming process, no thruster intervention is required, which reduces the configuration requirements of the vehicle propulsion system. During the stationing process, ultra-low energy consumption is achieved, and no power system intervention is required, which enables the unmanned submersible to achieve underwater standby, greatly improving the underwater self-sustaining power of the vehicle.

[0036] (2) The present invention relies on the generated negative buoyancy to achieve stationing, which can fully realize underwater static position maintenance and has better attitude stability than the dynamic positioning method. It can perform tasks that require fixed-point operations or have high requirements on working attitude, thus broadening the application scenarios of the unmanned aerial vehicle platform.

[0037] (3) The present invention does not require power device control during the stationing process, has good energy economy, can extend the underwater working (or standby) time of the aircraft, and greatly improves the underwater self-sustaining capacity of the aircraft system.

[0038] (4) The present invention adopts a retractable base unit, which can be retracted into the interior of the aircraft when the aircraft is in navigation state. Compared with the fixed base solution, the external fluid resistance is small, which can reduce the energy consumption of the aircraft during navigation and has relatively better navigation control performance.

[0039] (5) The bottom-station control unit of the present invention can interact with the integrated control system of the aircraft, collect the operation information of the aircraft, and then control the buoyancy adjustment unit to ensure that the bottom-station and floating processes of the aircraft are smooth. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a front view of the overall structure of the present invention;

[0041] Figure 2 It is a side view of the overall structure of the present invention;

[0042] Figure 3 This is a bottom flow chart of the present invention;

[0043] Figure 4 This is a floating flow chart of the present invention;

[0044] Among them: 1-recoverable base unit, 11-telescopic legs, 12-buoyancy footrest, 2-buoyancy adjustment unit, 3-bottom-station control unit, 4-vehicle. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0046] The present embodiment provides a system for parking an underwater unmanned vehicle on the bottom, which can realize the parking of the unmanned vehicle on the bottom and maintain its static position on the bottom, meet the requirements of the platform attitude stability in scenarios such as load deployment and recovery, and can switch between the floating and stationary states at any time.

[0047] like Figure 1 and Figure 2 As shown, the bottom-stationing system includes: a recoverable bottom unit 1, a buoyancy adjustment unit 2 and a bottom-stationing control unit 3.

[0048] The recyclable bottom unit 1 is arranged at the bottom of the vehicle 4, and its main function is to provide a fulcrum for the vehicle 4 to contact the seabed when the vehicle 4 is at the bottom, so as to ensure that the vehicle 4 lands smoothly and maintains a certain height from the seabed, so as to prevent the vehicle 4 from being buried by the quicksand on the seabed during its static stay at the bottom. The recyclable bottom unit 1 can be extended and retracted relative to the vehicle 4, and can be in two states: retracted and extended. When the vehicle 4 is in the navigation state, the recyclable bottom unit 1 is retracted into the interior of the vehicle 4, and the whole does not protrude from the shape of the vehicle 4, and does not affect the fluid performance of the vehicle 4; when the recyclable bottom unit 1 is needed to provide support for the vehicle 4, the recyclable bottom unit 1 is extended to provide stable support for the vehicle 4.

[0049] As an example, two recoverable bottom units 1 are arranged on both sides of the bottom axis of the aircraft 4, and the recoverable bottom units 1 on both sides are symmetrical along the axis of the aircraft 4; and are respectively located at the bow and stern of the aircraft 4.

[0050] The recyclable base unit 1 includes: telescopic legs 11, buffer feet 12 and a locking mechanism (not shown in the figure); the fixed end of the telescopic legs 11 is connected to the aircraft 4, and the buffer feet 12 are provided at the end of the telescopic end; when the aircraft 4 is in the navigation state, the recyclable base unit 1 does not work, the telescopic legs 11 are retracted inside the aircraft 4, and the buffer feet 12 at the end thereof are in the same shape as the aircraft 4, and the whole does not protrude from the aircraft shape, and does not affect the fluid performance of the aircraft; when the recyclable base unit 1 is needed to provide support for the aircraft 4, the telescopic legs 11 are extended to provide support for the aircraft 4.

[0051] To ensure the stability of the support, the two symmetrically arranged recyclable base units 1 are opened outward at a certain angle relative to the aircraft 4 when extended (i.e., symmetrically unfolded at a certain angle relative to the aircraft 4), forming an eight-shaped shape, thereby providing stable support for the aircraft 4.

[0052] The buffer foot 12 is the fulcrum for the vehicle 4 to contact the seabed, and its main function is to bear the negative buoyancy of the vehicle 4 when it is statically stationary at the bottom, disperse the pressure on the contact surface to prevent sinking, and absorb the impact load during the process of falling and touching the bottom.

[0053] The locking mechanism is used to limit and lock the telescopic legs 11 in both retracted and extended states to meet the force and structural stability requirements of the telescopic legs 11 when working (the locking mechanism can adopt a conventional position locking mechanism).

[0054] The buoyancy regulating unit 2 is arranged on the aircraft 4, and its main function is to provide positive and negative buoyancy for the aircraft 4 through buoyancy regulation, so as to ensure that the aircraft 4 can achieve stable ascent and descent by relying on its own weight without power intervention.

[0055] As an example, a set of buoyancy regulating units 2 is respectively provided at the bow and stern of the vehicle 4 .

[0056] As an example, the buoyancy regulating unit 2 includes: a water tank, a liquid level sensor disposed in the water tank, and a water inlet and outlet pump connected to the water tank. The liquid level sensor monitors the water level in the water tank in real time and sends it to the bottom-station control unit 3, and the water inlet and outlet pump is controlled by the bottom-station control unit 3. The bottom-station control unit 3 can realize independent control of two sets of buoyancy regulating units 2.

[0057] The main functions of the bottom-station control unit 3 are to interact with the integrated control system of the aircraft 4, collect data from sensors related to the aircraft system (such as the aircraft's attitude information, altitude information, depth information, etc.), perform timing control on the actions of the buoyancy adjustment unit 2 and the recoverable bottom unit 1 (specifically, to control the telescopic legs of the recoverable bottom unit 1 and the water inlet and outlet pumps of the buoyancy adjustment unit 2), perform real-time detection of the action status of the buoyancy adjustment unit 2 and the recoverable bottom unit 1, etc., to achieve control of the entire process of stable bottom stationing and floating.

[0058] The bottom-station control unit 3 is electrically connected to the recoverable bottom seat unit 1 and the buoyancy adjustment unit 2 through a watertight cable to achieve power supply and signal transmission.

[0059] Figure 1 and Figure 2A specific structure of the underwater unmanned vehicle bottom-staying system is given. In terms of system composition and installation interface, in order to ensure that the vehicle 4 works reliably in the bottom-staying state, a single vehicle 4 is equipped with four sets of recoverable bottom-staying units 1, two sets of buoyancy adjustment units 2 and one set of bottom-staying control unit 3. Among them, the four sets of recoverable bottom-staying units 1 are divided into two groups and installed on the front and rear sides of the buoyancy center of the vehicle 4 along the bow and stern directions, and two sets in each group are symmetrically distributed along the axis of the vehicle 4; the specific installation position can be designed in combination with the overall equipment layout of the vehicle, and the stability of the four-point bottom-touching support needs to be ensured. The two sets of buoyancy adjustment units 2 are respectively installed near the front and rear two sets of recoverable bottom-staying units 1 along the bow and stern directions. The adjustment capacity of the buoyancy adjustment unit 2 needs to be carried out according to the overall counterweight design of the vehicle to ensure the balance of the buoyancy moment of the two sets of buoyancy adjustment units 2 during the working process, that is, the resultant force generated by the two sets of buoyancy adjustment units 2 should ensure that the vehicle is always in a horizontal posture. The bottom-staying control unit 3 can be integrated with the vehicle system equipment and installed inside the pressure-resistant dry cabin, or it can be installed in a separate watertight cabin.

[0060] The system works as follows:

[0061] The bottom working process (static diving) is as follows Figure 3 As shown:

[0062] S11: The vehicle arrives at the underwater target position (the target position is the position where the vehicle is ready to start unpowered diving). The detection system on the vehicle 4 comprehensively judges the topography, bottom water flow and other conditions of the target position through environmental perception to see whether the conditions for the vehicle to stay at the bottom for unpowered diving are met. When the conditions for staying at the bottom for unpowered diving are met, a bottom stop instruction is sent to the bottom stop control unit 3;

[0063] S12: After receiving the seat bottom command, the station control unit 3 controls the telescopic legs of the recyclable seat bottom unit 1 to unfold, and after the legs are fully unfolded, the locking mechanism locks the telescopic legs to a limited position;

[0064] S13: the buoyancy regulating unit 2 at the bow and stern starts to work, injecting water into the water tank to generate negative buoyancy, so that the vehicle 4 dives without power under the action of the negative buoyancy;

[0065] During the dive of the aircraft 4, the bottom-stationed control unit 3 collects the attitude information, altitude information, and depth information of the aircraft system in real time to determine the state of the aircraft 4 during the current descent, such as whether the attitude of the aircraft 4 remains horizontal, whether the descent speed is within the set range, etc.; once the set control parameters are exceeded (such as the pitch angle exceeds the set range or the descent speed exceeds the set range, etc.), the bottom-stationed control unit 3 will adjust the attitude of the aircraft 4 by controlling the water injection flow and total water injection of the buoyancy adjustment unit 2, adjusting the water intake ratio of the bow and stern water tanks, etc., and finally realize closed-loop control of the attitude through feedback of the system attitude information, altitude information, and depth information; thereby, the attitude of the aircraft is stable and the descent speed is stable during the dive.

[0066] S14: When the aircraft 4 lands close to the seabed, the buffer foot of the recyclable bottom unit 1 contacts the seabed. Due to the certain initial velocity of the descent, there will be an instantaneous inertial impact. This part of the impact force is absorbed by the buffer foot and the telescopic legs. After that, the aircraft 4 tends to be stable and presents a static bottom state. In this process, the bottom control unit 3 collects the aircraft attitude information, detects the instantaneous acceleration change, and combines the depth change information to determine whether the entire bottom-stopping process is completed (i.e., whether it touches the bottom). If it is completed, it proceeds to the next step, otherwise it returns to step S13;

[0067] S15: After the aircraft 4 completes the bottoming action and its posture is stable, the buoyancy adjustment unit 2 continues to inject water into the water tank to the set value, further increasing the negative buoyancy of the aircraft 4, ensuring the stability of the bottom and preventing the aircraft 4 from being displaced under the impact of the bottom water flow.

[0068] S16: The entire bottom-stationing process is completed, and the aircraft 4 enters the bottom-stationing state. The aircraft 4 turns off the corresponding power equipment, instruments and equipment, etc., and can enter the ultra-low power consumption standby mode.

[0069] like Figure 4 As shown in the figure, the floating process can be regarded as the reverse process of the bottom dwelling process. The specific workflow is as follows:

[0070] S21: After receiving the floating instruction issued by the upper system, the bottom control unit 3 enters the working state from the standby state;

[0071] S22: The bottom-stationed control unit 3 controls the buoyancy regulating unit 2 to drain the water tank; while the buoyancy regulating unit 2 is continuously draining water, the bottom-stationed control unit 3 collects information on the vehicle's attitude and depth change, and determines the vehicle's lift-off status (such as instantaneous changes in acceleration, changes in depth in a short period of time, etc.); if it is determined that the vehicle 4 has floated off the ground, the next step is entered, otherwise the buoyancy regulating unit 2 is controlled to continuously drain the water tank until it is determined that the vehicle 4 has floated off the ground.

[0072] S23: After detecting that the aircraft floats off the ground, the bottom-station control unit 3 monitors the stability of the aircraft's floating posture, adjusts the displacement of the buoyancy adjustment unit 2, and performs posture control on the aircraft 4. Specifically, the bottom-station control unit 3 controls the flow of the buoyancy adjustment unit 2 according to the posture change, and controls the overall positive buoyancy, floating speed, etc. of the aircraft by switching the inlet and outlet states, until the state of the aircraft 4 is stable and the buoyancy adjustment amount finally reaches the target setting value;

[0073] S24: The locking mechanism of the recoverable base unit 1 is released, the telescopic legs 11 are retracted, the recoverable base unit 1 works in a navigation state, and the floating process is completed.

[0074] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A system for stopping underwater unmanned vehicles at the bottom, characterized in that: include: A recoverable bottom unit (1), a buoyancy adjustment unit (2) and a bottom-staying control unit (3); The recyclable base unit (1) is arranged at the bottom of the vehicle (4) to provide a fulcrum for the vehicle (4) to contact the seabed when the vehicle (4) is stationary; the recyclable base unit (1) can be extended and retracted relative to the vehicle (4) to achieve two states: retracted and extended; The buoyancy adjustment unit (2) is arranged on the aircraft (4) and provides positive or negative buoyancy for the aircraft (4) through buoyancy adjustment, so that the aircraft (4) can float up or dive down; The recoverable base unit (1) and the buoyancy adjustment unit (2) are controlled by the bottom-station control unit (3).

2. The underwater unmanned vehicle bottom-stationing system according to claim 1, characterized in that: The recyclable base unit (1) comprises: telescopic legs (11), a buffer foot seat (12) and a locking mechanism; The fixed end of the telescopic leg (11) is connected to the aircraft (4), and a buffer foot seat (12) is provided at the end of the telescopic leg; when the aircraft (4) is in a navigation state, the telescopic leg (11) is retracted inside the aircraft (4), and the buffer foot seat (12) at the end thereof is in the same shape as the aircraft (4); when the recyclable base unit (1) is required to provide support for the aircraft (4), the telescopic leg (11) is extended; The locking mechanism is used to limit and lock the telescopic legs (11) in both the retracted and extended states.

3. The underwater unmanned vehicle bottom-stationing system according to claim 1 or 2, characterized in that: Four sets of recoverable base units (1) are divided into two groups and installed along the bow and stern directions on both sides of the buoyancy center of the craft (4), and two sets of recoverable base units (1) in each group are symmetrically arranged along the axial direction of the craft (4).

4. The underwater unmanned vehicle bottom-stationing system according to claim 3, characterized in that: When the two sets of symmetrically arranged recyclable seat bottom units (1) are extended, they open outward at a set angle relative to the aircraft (4).

5. The underwater unmanned vehicle bottom-stationing system according to claim 1, characterized in that: The buoyancy regulating unit (2) comprises: a water tank, a liquid level sensor arranged in the water tank, and a water inlet and outlet pump connected to the water tank; The liquid level sensor monitors the water level in the water tank in real time and sends the information to the bottom-station control unit (3); the water inlet and outlet pumps are controlled by the bottom-station control unit (3).

6. The underwater unmanned vehicle bottom-stationing system according to claim 5, characterized in that: The two sets of buoyancy adjustment units (2) are respectively installed in the fore and aft directions on both sides of the buoyancy center of the vehicle (4).

7. The underwater unmanned vehicle bottom-stationing system according to claim 1, 2, 5 or 6, characterized in that: The bottom-stationed control unit (3) is capable of interacting with the integrated control system of the aircraft (4) to collect operation information of the aircraft (4), including but not limited to attitude information, altitude information, and depth information of the aircraft (4).

8. A method for controlling an underwater unmanned vehicle to stay at the bottom, characterized in that: The control process of implementing the bottom-stationing system for underwater unmanned vehicles according to any one of claims 1 to 7 to station the vehicle (4) at the bottom is as follows: S11: the aircraft (4) arrives at an underwater target position, the target position being a position where the aircraft (4) is ready to start unpowered diving; When the aircraft (4) meets the bottom-stationing condition for unpowered diving, a bottom-stationing instruction is sent to the bottom-stationing control unit (3); S12: After receiving the bottom seat instruction, the bottom station control unit (3) controls the recyclable bottom seat unit (1) to extend; S13: the bottom-station control unit (3) controls the buoyancy regulating unit (2) to start working, providing negative buoyancy for the aircraft (4), so that the aircraft (4) dives without power under the action of the negative buoyancy; During the diving process of the aircraft (4), the bottom-station control unit (3) controls the buoyancy regulating unit (2) according to the state of the aircraft (4) during the current descent process, so that the attitude and descent speed of the aircraft (4) during the diving process are stable; S14: When the bottom-parking control unit (3) determines that the recoverable bottom-mounted unit (1) has touched the bottom, the buoyancy regulating unit (2) continues to inject water into the water tank to a set value; then the entire bottom-parking process is completed, and the vehicle (4) enters a bottom-parking state.

9. The method for controlling the underwater unmanned vehicle to stay at the bottom as claimed in claim 8, characterized in that: The process of controlling the aircraft to float up is as follows: S21: After receiving the floating instruction, the bottom-station control unit (3) enters the working state from the standby state; S22: the bottom-station control unit (3) controls the buoyancy adjustment unit (2) to provide positive buoyancy for the aircraft (4), and determines the lift-off state of the aircraft (4): if it is determined that the aircraft (4) has lifted off the ground, the next step is entered; otherwise, the buoyancy adjustment is continued until it is determined that the aircraft (4) has lifted off the ground; S23: the bottom-station control unit (3) controls the buoyancy adjustment unit (2) to perform attitude control on the aircraft (4) until the state of the aircraft (4) reaches a stable state and the buoyancy adjustment amount finally reaches a target set value; S24: The recyclable base unit (1) is retracted and the floating process is completed.

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