Unmanned submersible mooring system and control method

Abstract

The invention provides an unmanned submersible mooring system and a control method for solving the problem that an unmanned submersible lacks an effective mooring means. The mooring system comprises a sensor acquisition system, a control system, a communication system, a propulsion system and the like, and the sensor acquisition system obtains submersible and environment information in all directions; the conformal vibration sensor can establish a waveform-speed database to improve the speed measurement accuracy; the control system generates a control instruction; the communication system provides reliable communication guarantee; and the propeller realizes six-degree-of-freedom movement. In addition, the energy system provides energy, and stable work of the system is guaranteed. The control method comprises the steps of sailing to a designated position, sailing position correction and remote communication, mooring entering and mooring keeping, mooring disengaging and the like. Stable mooring and efficient operation of the submersible in the complex marine environment are achieved, and the autonomy, the intelligent level and the task execution reliability of the submersible are improved.

Description

Technical Field

[0001] This invention relates to the field of unmanned surface vessel (USV) technology, and in particular to an unmanned submersible mooring system and control method. Background Technology

[0002] Currently, research on mooring unmanned underwater vehicles (UUVs) mainly focuses on mooring point location and identification, autonomous obstacle avoidance, path planning, and maneuvering control. It primarily addresses the issue of parking in designated locations, but subsequent mooring still requires shore-based facilities or human intervention. In practical marine applications, it's difficult to prepare a large number of island / reef facilities and floating platforms for this purpose, failing to solve the mooring problem at sea. Surface ships and submarines typically use anchor chains for mooring; remotely operated vehicles (ROVs) usually use umbilical cables, one end fixed to the mother ship for transmitting power and data and limiting their range of movement, relying on the mother ship's position; autonomous underwater vehicles (AUVs) focus on endurance, using mission completion as a substitute for mooring. However, in practical applications, there are specific requirements for mooring conditions.

[0003] There are two main ways for unmanned underwater vehicles to establish long-distance communication with shore-based / mother ships: one is through satellite communication, which is fast and has a wide range but has poor stealth; the other is through underwater acoustic communication, which has problems with low transmission rate and bit error rate but has strong seawater penetration capability.

[0004] Underwater acoustic communication typically employs a Doppler log (DVL), an acoustic sensor used to measure the velocity of an underwater vehicle relative to the seabed or body of water. It works by emitting sound waves from a transducer tilted downwards or outwards. These acoustic pulses are reflected back from particles suspended on the seabed or in the water and return to the sensor. The system then calculates the Doppler shift (the frequency change between the transmitted and received signals) to determine the vehicle's velocity in three dimensions (puff, sway, and heave).

[0005] DVL corrections to INS are typically achieved using a Kalman filter. The INS calculates its predicted position, velocity, and attitude based on its own inertial sensor data. Due to accumulated errors, this prediction gradually deviates from the true value.

[0006] DVL provides independent velocity measurements, which are compared with the velocity values ​​calculated by INS. The difference is used as an observation to drive the Kalman filter, estimating and correcting the INS error.

[0007] DVL is divided into bottom tracking and water tracking modes: Bottom tracking: Directly measures the velocity (absolute velocity) relative to the stationary seabed, offering high accuracy. The measured value Vg can be directly applied for correction.

[0008] Water tracking: When the water depth is too great for sound waves to reach the seabed, DVL will select a specific water layer to track. However, in actual use, the submersible is located in the open ocean at great depths, and the forces it experiences during underwater movement are complex, including fluid resistance (velocity), lift (attitude, structural form), and various accidental impacts. It is difficult to separate the resistance that is only related to velocity, and the measured pressure values ​​are complexly coupled, making it difficult to separate the velocity values. Therefore, the velocity calculated using DVL will have a large error and cannot be corrected for INS.

[0009] Therefore, we propose an unmanned submersible mooring system and control method. Summary of the Invention

[0010] Therefore, it is necessary to address the current technical problems of unmanned underwater vehicles (UUVs) lacking effective mooring methods, making it difficult to achieve stable mooring at sea, as well as poor concealment of long-distance communication and inaccurate speed measurement. This would enable UUVs to moor stably in complex marine environments, possess autonomous retrieval capabilities, adapt to various operational conditions, effectively solve mooring and communication challenges, and improve the reliability and stability of mission execution.

[0011] A first aspect of the present invention provides an unmanned submersible mooring system, comprising: The sensor acquisition system includes an inertial navigation system, a Doppler log, a depth sensor, a multibeam forward-looking sonar, a side-scan sonar, a terrain-aided navigation system, a GNSS receiver, and conformal vibration sensors. The control system, connected to the sensor acquisition system, includes a controller for processing information transmitted from the sensors and generating control commands based on preset tasks and algorithms. The communication system, connected to the control system, includes underwater acoustic communication equipment and satellite communication equipment. The underwater acoustic communication equipment is used for underwater information interaction and communication, and the satellite communication equipment is used for data transmission with shore-based / mother ship bases. The propulsion system, connected to the control system, includes a propulsion motor and a thruster. The thruster is used for navigation, maneuvering, and mooring operations of the submersible. Multiple conformal vibration sensors are installed on the surface of the submersible to capture the velocity-dependent pulsating pressure field generated when ocean currents flow over the surface of the submersible, and to acquire full-field vibration spectrum data and waveform data. Navigation speed data is obtained by receiving signals transmitted from the GNSS receiver via satellite communication, or by obtaining navigation speed data through the Doppler log and inertial navigation system, and a waveform-velocity database is established by combining the waveform data. Through the coordinated operation of its various subsystems, this system achieves stable mooring and efficient operation in complex marine environments. While relatively independent, the subsystems are interconnected, collectively forming a complete and powerful unmanned submersible mooring system. This provides a solid guarantee for the long-term residence of unmanned submersibles in the ocean and the execution of various missions, effectively solving the current problem of the lack of mooring means for unmanned submersibles.

[0012] In other embodiments, the sensor acquisition system includes: an inertial navigation system (INS) for acquiring the submersible's speed, position, and attitude information, possessing autonomy and stealth capabilities; a Doppler log for providing speed information and assisting the INS in correcting errors, reducing accumulated errors during long-distance navigation; a depth sensor for providing the submersible's depth information; a multibeam forward-looking sonar for real-time detection of the area in front of the submersible, forming an acoustic image of the forward fan-shaped area to detect obstacles in advance; a side-scan sonar, positioned on the hull side, for acquiring surrounding environmental information and supplementing the multibeam forward-looking sonar; a terrain-aided navigation system for terrain matching in moored conditions, providing a basis for the control system's decisions; and a GNSS receiver, positioned on the buoy system, for receiving satellite signals and achieving navigation and positioning functions. The sensor acquisition system can acquire information about the submersible's own status and the surrounding environment from all angles and perspectives. This information is crucial for the submersible's safe navigation, accurate positioning, and effective operation. By having different types of sensors work together, the limitations of a single sensor can be overcome, improving the accuracy and reliability of information acquisition and providing rich and accurate data support for subsequent control system decisions.

[0013] In other embodiments, the conformal vibration sensor establishes a waveform-velocity database in the following ways: During submersible navigation, waveform data is obtained through multiple conformal vibration sensors; navigation speed data is obtained by receiving signals transmitted from a GNSS receiver via satellite communication, and the relationship between waveform and velocity within that area is analyzed to establish the waveform-velocity database; or, at shallow water depths, navigation speed data is obtained through a Doppler log and inertial navigation system, combined with the waveform data obtained from the conformal vibration sensor to establish the waveform-velocity database. By establishing the waveform-velocity database, the submersible can quickly and accurately calculate its navigation speed based on real-time collected waveform data under different sea areas and current conditions, improving the accuracy and reliability of speed measurement.

[0014] In other embodiments, the controller in the control system calculates and analyzes position, speed, attitude, and environmental information transmitted by the sensor acquisition system using a preset algorithm to generate thruster speed control commands and servo motor angle control commands. As the "brain" of the unmanned submersible mooring system, the controller can analyze and process various sensor information to generate corresponding control commands, ensuring that the submersible performs navigation, obstacle avoidance, and path planning operations according to preset tasks and algorithms, thereby improving the submersible's autonomy and intelligence level.

[0015] In other embodiments, the underwater acoustic communication equipment in the communication system integrates an underwater acoustic communicator, a transducer, and a hydrophone, utilizing the properties of sound waves propagating in water for communication. The satellite communication equipment establishes a communication link with a satellite in Earth orbit by transmitting and receiving radio signals, enabling long-distance data transmission with a shore-based base or mother ship. Underwater acoustic communication equipment and satellite communication equipment each have their own characteristics and complement each other, providing reliable communication for the submersible. Underwater acoustic communication equipment is suitable for short-range underwater information exchange and communication, while satellite communication equipment enables long-distance data transmission with a shore-based base or mother ship, ensuring that the submersible can receive and send various instructions and information in a timely and accurate manner in the marine environment.

[0016] In other embodiments, the propulsion system comprises a combination of a main thruster, an auxiliary thruster, and a vertical thruster, or multiple thrusters arranged at an angle to achieve six degrees of freedom of movement. This thruster design enables the submersible to move freely in six directions: forward, backward, left, right, up, and down, improving its maneuverability and flexibility, and allowing it to adapt to various complex marine environments and mission requirements.

[0017] In other embodiments, the system further includes: an energy system connected to the propulsion system, control system, sensor acquisition system, and communication system, comprising a power battery for providing energy for the entire mission; and a support system connected to the control system, comprising a submersible structure, a buoyancy equalization system, a buoy system, and an operations module. The submersible structure provides hydrodynamic hull lines and equipment support frames; the buoyancy equalization system provides underwater buoyancy and adjusts the center of gravity; the buoy system serves as a working platform for the GNSS receiver and satellite communication equipment; and the operations module is optional depending on mission requirements. The energy system provides power to all subsystems of the unmanned submersible and is fundamental to its normal operation. The support system encompasses the submersible's structure, buoyancy adjustment, communication platform, and operations equipment, ensuring stable operation of the submersible in various marine environments and meeting the needs of different missions.

[0018] In other embodiments, the submersible in the support system adopts a streamlined shape design to reduce drag during underwater navigation and improve navigation efficiency. The submersible balancing system controls the buoyancy of the submersible by adjusting the buoyancy device inside the submersible, enabling it to maintain a stable suspended state in the water. The streamlined shape design reduces the submersible's drag, increases its speed and endurance; the submersible balancing system adjusts the submersible's buoyancy and center of gravity, improving its stability and maneuverability, and ensuring the safety and stability of the submersible during navigation and mooring.

[0019] In other embodiments, the buoy system, equipped with a winch and cable, serves as a working platform for the GNSS receiver and satellite communication equipment after being deployed to the sea surface upon receiving instructions. The operational modules are optional and include underwater cameras, various types of active and passive sonar, and robotic arms, depending on mission requirements. The buoy system provides a stable working platform for the GNSS receiver and satellite communication equipment, ensuring accurate reception of satellite signals and data transmission when the submersible surfaces or communicates with the outside world via the buoy. The operational modules are optional and can be selected according to different mission requirements, enabling the unmanned submersible to perform various specific tasks, such as underwater observation, sampling, and retrieval, thus improving the submersible's versatility and applicability.

[0020] A second aspect of the present invention provides a control method for an unmanned submersible mooring system, comprising the following steps: S1. Navigating to the designated location: The target point is preset using latitude and longitude coordinates, and a mooring state is maintained within a certain range. During the entire navigation process, the submersible is fully submerged in water, and real-time position and attitude information are calculated using the inertial navigation system and Doppler log. Surrounding obstacles are detected using multibeam forward-looking sonar, and depth information is provided by depth sensors. The controller receives the data from the sensor acquisition system and performs calculations and analysis according to preset algorithms to achieve obstacle avoidance and path planning. This step provides clear targets and constraints for the submersible's navigation and mooring, reduces the influence of external factors, improves the stability and safety of navigation, and ensures that the submersible can successfully reach the designated location.

[0021] S2. Navigation Position Correction and Long-Distance Communication: In safe waters or in emergency situations, buoys are released to achieve satellite navigation via GNSS receivers and long-distance communication via satellite communication equipment; during navigation, underwater acoustic communication equipment is used for most of the time, and communication is established via extremely low frequency / very low frequency. When the water is at a greater depth, multiple conformal vibration sensors capture the velocity-dependent pulsating pressure field generated when ocean currents flow over the surface of the submersible. Combined with a waveform-velocity database, the ocean current velocity vector is calculated in real time from the waveform. This step employs different navigation and communication methods under different conditions, ensuring the submersible's positioning and communication needs are met in various environments. Simultaneously, the real-time calculation of the ocean current velocity vector using conformal vibration sensors improves the accuracy of velocity measurements.

[0022] S3. Entering and Maintaining Mooring: Upon reaching the preset location, the terrain-aided navigation system scans and samples the terrain data within the preset range, simultaneously obtaining a waveform-velocity model database. After sampling, it returns to the designated mooring point, shuts off the thrusters, and retains the inertial navigation system, Doppler log, and terrain-aided navigation system. Through motion sensing and terrain comparison, it ensures the submersible remains within the designated area. When the controller calculates, based on navigation parameter inputs, that the submersible has left the mooring range, it activates the terrain-aided navigation system for confirmation. Once the database confirms the departure from the area, it activates the thrusters to return to the preset mooring point. If the verification result still indicates the submersible is within the mooring range, the sensor parameters are corrected. At regular intervals, the terrain-aided navigation system corrects the inertial navigation system to avoid accumulated errors. This step, through the coordinated work of the terrain-aided navigation system and the inertial navigation system, ensures the submersible's positioning accuracy while moored, and simultaneously corrects sensor parameters, improving the system's reliability and stability.

[0023] S4. Demoting: When the submersible needs to leave the system to perform operations according to preset mission instructions at a designated time, or according to instructions issued via remote communication, the thrusters and operation modules are activated. This step enables the submersible to promptly leave the moored state to perform various operational tasks, improving the submersible's versatility and applicability. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the mooring system for the unmanned submersible in this invention.

[0025] Figure 2 This is a flowchart of the control method for the mooring system of the unmanned submersible in this invention.

[0026] in: 1. Sensor Acquisition System; 1.1 Inertial Navigation System; 1.2 Doppler Log; 1.3 Depth Sensor; 1.4 Multibeam Forward-Looking Sonar; 1.5 Side-Scan Sonar; 1.6 Terrain-Aided Navigation System; 1.7 GNSS Receiver; 2. Control System; 2.1 Controller; 3. Communication System; 3.1 Underwater Acoustic Communication Equipment; 3.2 Satellite Communication Equipment; 3.3 The working platform of the satellite communication equipment, i.e., part of the functions of the buoy system; 4. Propulsion System; 4.1 Propulsion Motor; 4.2 Thruster; 5. Energy System; 5.1 Power Battery; 6. Support System; 6.1 Submersible Structure; 6.2 Submersible Equilibrium System; 6.3 Buoy System; 6.4 Operation Module. Detailed Implementation

[0027] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0028] Example 1 like Figure 1 As shown, the unmanned submersible mooring system in this embodiment mainly consists of a sensor acquisition system 1, a control system 2, a communication system 3, a propulsion system 4, an energy system 5, and a support system 6. Through the coordinated operation of these subsystems, this unmanned submersible mooring system achieves stable mooring and efficient operation in complex marine environments. Each subsystem is relatively independent yet interconnected, collectively forming a complete and powerful unmanned submersible mooring system. This system architecture provides a solid guarantee for the long-term residence and multi-tasking execution of unmanned submersibles in the ocean, effectively solving the current problem of the lack of mooring methods for unmanned submersibles.

[0029] Specifically, the sensor acquisition system 1 in this embodiment includes: an inertial navigation system device 1.1, a Doppler log 1.2, a depth sensor 1.3, a multibeam forward-looking sonar 1.4, a side-scan sonar 1.5, a terrain-aided navigation system 1.6, a GNSS receiver 1.7, and a conformal vibration sensor.

[0030] Sensor acquisition system 1 can acquire information about the submersible's own status and the surrounding environment from all angles and perspectives. This information is crucial for the submersible's safe navigation, precise positioning, and effective operation. By having different types of sensors work together, the limitations of a single sensor can be overcome, improving the accuracy and reliability of information acquisition and providing rich and accurate data support for subsequent control system decisions.

[0031] Among them, the inertial navigation device 1.1 obtains the velocity, position, and attitude information of the submersible, possessing autonomy and stealth; the inertial navigation system device 1.1 obtains the velocity, position, and attitude information of the vehicle by measuring the acceleration of the vehicle in the inertial reference frame and performing integration calculations. Its autonomy is reflected in its ability to complete navigation tasks without relying on external information, while its stealth gives it a unique advantage in fields such as military applications where stealth requirements are high.

[0032] The Doppler log 1.2 provides velocity information to assist in correcting the inertial navigation system 1.1, reducing accumulated errors during long-distance voyages. Utilizing the Doppler effect, the Doppler log 1.2 measures the submersible's velocity relative to the seabed or water body by emitting sound waves and receiving reflected waves. When used in conjunction with the inertial navigation system 1.1, it periodically provides velocity information to the inertial navigation system, correcting for accumulated errors caused by integration calculations. During long-distance, long-duration voyages, this correction effectively improves navigation accuracy, ensuring the submersible accurately reaches its designated location. For example, during transoceanic voyages, the Doppler log 1.2's auxiliary corrections can prevent navigational deviations caused by excessive accumulated errors in the inertial navigation system.

[0033] The multibeam forward-looking sonar 1.4 provides real-time detection of the area in front of the submersible, generating an acoustic image of the fan-shaped region ahead and detecting obstacles in advance. By emitting multiple sound beams, the multibeam forward-looking sonar 1.4 scans an area within a certain angle and distance in front of the submersible. It can generate real-time acoustic images of the area ahead, clearly displaying the location, shape, and size of obstacles. This allows the submersible to detect obstacles in advance during navigation, adjust its course in time, and avoid collisions. For example, in complex underwater terrain, such as reef areas or shipwreck areas, the multibeam forward-looking sonar 1.4 can detect obstacles in advance, ensuring the safe navigation of the submersible.

[0034] Side-scan sonar 1.5 is deployed on the side of the submersible to obtain information about the surrounding environment, supplementing the multibeam forward-looking sonar 1.4. Side-scan sonar 1.5 is mounted on the side of the submersible and acquires environmental information to the side of the submersible by emitting sound waves to the side and receiving reflected waves. It complements multibeam forward-looking sonar 1.4, which primarily focuses on the area ahead, while side-scan sonar 1.5 expands the range of environmental perception, enabling the detection of obstacles and terrain features to the side. For example, when navigating in narrow waterways, side-scan sonar 1.5 can help the submersible detect reefs or other submersibles to the side in a timely manner, ensuring navigational safety.

[0035] The terrain-aided navigation system 1.6 is used for terrain matching in mooring situations, providing a basis for the control system 2's judgment. The terrain-aided navigation system 1.6 uses pre-stored terrain data to match the terrain information acquired by the submersible in real time. During mooring, terrain matching can determine the submersible's precise position, providing a basis for the control system 2 to determine whether the submersible is within the mooring range. For example, when mooring in areas with complex seabed topography, the terrain-aided navigation system 1.6 can accurately identify the terrain features around the submersible, ensuring that the submersible is stably moored in the designated position.

[0036] GNSS receiver 1.7 is mounted on buoy system 6.3 to receive satellite signals and provide navigation and positioning capabilities. GNSS receiver 1.7 calculates the submersible's position information by receiving signals transmitted by satellites. Its placement on buoy system 6.3 allows for accurate navigation and positioning information when the submersible surfaces or communicates with the outside world via the buoy. For example, when the submersible needs to precisely dock with a shore-based support or mother ship, the positioning information provided by GNSS receiver 1.7 can guide the submersible to the docking position accurately.

[0037] Multiple conformal vibration sensors are deployed on the surface of the submersible to capture the velocity-dependent pulsating pressure field generated when ocean currents flow over the surface. The ocean current velocity vector is calculated in real time from the vibration patterns. The principle is as follows: Conformal vibration sensors are deployed on the outer surface of the submersible. Due to the varying locations and large number of sensors, the instantaneous recorded values ​​are diverse and numerous. For example, within a 10-minute timeframe, the first minute shows waveform 'a', minutes 2-4 show waveform 'b', and minutes 5-10 show waveform 'c', meaning the first minute represents velocity 'a', minutes 2-4 show velocity 'b', and minutes 5-10 show velocity 'c'. When ocean currents flow over the submersible surface, they generate a velocity-dependent pulsating pressure field. These pulsating pressure fields at different locations and times exhibit unique vibration patterns. By collecting and analyzing vibration signals from numerous conformal vibration sensors at different locations and times, a model relating the vibration patterns to the ocean current velocity vector can be established. Using this model, the ocean current velocity vector can be calculated from the real-time acquired vibration signals. Multiple conformal vibration sensors can acquire full-field vibration spectrum data, and subsequently, waveform data. Distributed at different locations on the submersible, these sensors comprehensively acquire vibration information from the submersible's surface, forming full-field vibration spectrum data. Further analysis and processing of this spectrum data yields waveform data from different locations. This waveform data contains rich ocean current information, providing fundamental data support for the subsequent establishment of a waveform-velocity database.

[0038] Simultaneously, a waveform-velocity database for the region is established through sensor acquisition system 1, that is, the navigation speed is derived from the waveform. The specific methods for establishing the database include: First, waveform data of the submersible during its voyage can be obtained using multiple conformal vibration sensors. During the submersible's voyage, these sensors collect vibration signals from the submersible's surface in real time and convert them into waveform data. This waveform data reflects the vibration characteristics generated by the interaction between the ocean current and the submersible, and is closely related to the ocean current velocity.

[0039] Subsequently, the GNSS receiver 1.7 acquires the submersible's precise position and speed information via satellite communication. This speed data is then correlated with waveform data collected by conformal vibration sensors. Through extensive data acquisition and statistical analysis, a mathematical model between waveform and speed is established, forming a waveform-speed database. This database provides a basis for quickly and accurately calculating the submersible's speed based on real-time waveform data under different sea areas and current conditions.

[0040] At shallow water depths, the Doppler log 1.2 can employ bottom-tracking mode to directly measure the submersible's absolute velocity relative to the seabed. Simultaneously, the inertial navigation system 1.1 provides information such as the submersible's attitude and acceleration. By comprehensively analyzing the velocity data measured by the Doppler log 1.2, the information provided by the inertial navigation system 1.1, and the waveform data acquired by the conformal vibration sensor, the relationship between waveform and velocity can be established more accurately, further refining the waveform-velocity database. This multi-sensor fusion method improves the accuracy and reliability of the database.

[0041] Control system 2 mainly consists of controller 2.1. It is responsible for processing information transmitted from sensors and generating control commands based on preset tasks and algorithms. Controller 2.1 receives various information from sensor acquisition system 1, including position, velocity, attitude, and environmental information. Based on preset task requirements and control algorithms, it analyzes and processes this information to generate corresponding control commands, such as thruster speed control and servo angle control. For example, when the sensors detect that the submersible deviates from its predetermined course, controller 2.1 calculates the required servo angle adjustment based on the algorithm and issues a control command to rotate the servo, thereby correcting the course.

[0042] Communication system 3 includes: underwater acoustic communication equipment 3.1 and satellite communication equipment 3.2. Communication system 3 ensures that the submersible can receive and transmit various commands and information in a timely and accurate manner in the marine environment. The underwater acoustic communication equipment and satellite communication equipment each have their own characteristics and complement each other, providing reliable communication support for the submersible.

[0043] The underwater acoustic communication device 3.1 integrates an underwater acoustic communicator, transducer, and hydrophone, enabling complete underwater acoustic communication functions and facilitating underwater information exchange and communication. The device generates and modulates electrical signals; the transducer converts these signals into acoustic waves and transmits them into the water; the hydrophone receives the acoustic waves and converts them back into electrical signals, which are then demodulated and processed by the underwater acoustic communicator. In this way, the underwater acoustic communication device 3.1 enables information exchange and communication between the submersible and other underwater equipment or the mother ship. For example, in multi-submersible collaborative operations, the device can be used for data sharing and command transmission between submersibles.

[0044] Satellite communication equipment 3.2 utilizes radio waves to transmit data with shore-based / mothership targets via air. By transmitting and receiving radio signals, satellite communication equipment 3.2 establishes a communication link with satellites in Earth orbit, thereby enabling long-distance data transmission with shore-based or mothership targets.

[0045] The propulsion system 4 mainly consists of propulsion motors 4.1 and thrusters 4.2. Propulsion system 4 provides power support for the submersible's navigation, maneuvering, and mooring operations. The proper configuration and coordinated operation of propulsion motors 4.1 and thrusters 4.2 enable the submersible to achieve various complex movements. Thrusters 4.2 can be a combination of main thrusters, auxiliary thrusters, and vertical thrusters, or multiple thrusters arranged at angles to achieve 6 degrees of freedom of movement.

[0046] Energy system 5 primarily consists of power battery 5.1, which is responsible for supplying energy to the entire mission. Power battery 5.1 provides power support to all subsystems of the unmanned underwater vehicle and is fundamental to its normal operation. It needs to have sufficient energy density and endurance to meet the needs of the submersible for long-term missions. At the same time, power battery 5.1 also needs to have good safety and reliability to ensure stable operation in the marine environment.

[0047] The support system 6 includes: submersible structure 6.1, buoyancy control system 6.2, buoy system 6.3, and operational module 6.4. Support system 6 covers the submersible's structure, buoyancy adjustment, communication platform, and operational equipment, ensuring stable operation in various marine environments. Specifically, the submersible structure 6.1 provides hydrodynamic hull lines and a support frame for various types of equipment; the buoyancy control system 6.2 provides underwater buoyancy and adjusts the center of gravity and center of buoyancy; the buoyancy control system 6.2 controls the submersible's buoyancy by adjusting internal buoyancy devices, such as ballast tanks, to maintain a stable suspended state in the water. Simultaneously, by adjusting the internal mass distribution of the submersible, the position of the center of gravity and center of buoyancy can be adjusted, improving the submersible's stability and maneuverability.

[0048] The buoy system 6.3, equipped with a winch and cable, serves as a working platform for the GNSS receiver 3.2 and satellite communication equipment 3.3 after receiving a deployment command and being released to the sea surface. Upon receiving the deployment command, the winch releases the cable, deploying the buoy to the sea surface. The buoy floats on the sea surface, providing a stable working platform for the GNSS receiver 3.2 and satellite communication equipment 3.3. The GNSS receiver 3.2 can accurately receive satellite signals from the buoy to obtain the submersible's position information; the satellite communication equipment 3.3 can communicate with the outside world through the buoy, enabling data transmission and command reception.

[0049] Operation Module 6.4 is optional and can include, but is not limited to, underwater cameras, various types of active and passive sonar, and robotic arms, depending on the mission requirements. Operation Module 6.4 is a set of optional equipment that enables the unmanned submersible to complete various specific tasks. Underwater cameras can be used for underwater environmental observation and imaging, acquiring high-definition underwater images; various types of active and passive sonar can be used for underwater target detection and identification, providing information on the target's location, shape, and movement; and robotic arms can be used for tasks such as grasping, manipulating, and sampling underwater objects. For example, in marine archaeological missions, robotic arms can grasp artifacts from the seabed; in underwater environmental monitoring missions, underwater cameras and sonar can monitor changes in the marine ecological environment in real time.

[0050] Example 2 like Figure 2 As shown in the figure, this embodiment discloses a control method for an unmanned submersible mooring system, which includes the following steps: 1) Navigation to the Designated Position: Upon commencement of the mission, the target point is first preset using latitude and longitude coordinates, and a mooring range is established. The submersible remains submerged throughout the voyage. Real-time position and attitude information are calculated using the inertial navigation system 1.1 and the Doppler log 1.2. During navigation, surrounding obstacles are detected using a multibeam forward-looking sonar 1.4, and depth information is provided by a depth sensor 1.3. The controller 2.1 receives data from the sensor acquisition system 1 and performs calculations and analysis based on a preset algorithm to achieve obstacle avoidance and path planning. At the start of the mission, the target point is preset using precise latitude and longitude coordinates, and the mooring range is set, providing clear targets and constraints for the submersible's navigation and mooring. Full submersion throughout the voyage reduces the submersible's exposure to external factors such as surface waves and wind, improving navigation stability. The combined use of the inertial navigation system 1.1 and the Doppler log 1.2 enables real-time and accurate acquisition of the submersible's position and attitude information, providing a basis for the controller 2.1 to perform path planning and obstacle avoidance decisions. The multibeam forward-looking sonar 1.4 can detect obstacles ahead in advance, the depth sensor 1.3 provides the depth information of the submersible, and the controller 2.1 uses preset algorithms to analyze and calculate based on this information, plan a safe navigation path, avoid obstacles, and ensure that the submersible successfully reaches the designated location.

[0051] 2) Navigation Position Correction and Long-Distance Communication: In rare cases, such as in safe waters or emergencies, buoy 6.3 can be deployed for satellite navigation via GNSS receiver 1.7 and long-distance communication via satellite communication equipment 3.2. During navigation, underwater acoustic communication equipment 3.1 is used for the majority of the time, establishing communication via extremely low frequency (ULF) / very low frequency (VLF). Deploying buoy 6.3 in safe waters or emergencies, and utilizing GNSS receiver 1.7 for high-precision satellite navigation, allows for rapid and accurate determination of the submersible's position. Simultaneously, satellite communication equipment 3.2 enables long-distance communication with shore-based facilities or the mother ship, facilitating the timely transmission of important information and the receipt of commands. During normal navigation, underwater acoustic communication equipment 3.1 is used for communication most of the time. ULF / VLF sound waves have good propagation characteristics in water, penetrating deeper water layers to achieve reliable underwater communication. For example, when performing missions in the open sea, the underwater acoustic communication equipment 3.1 can realize data transmission and command transmission between the submersible and the mother ship within a certain range; while when it is necessary to communicate with a shore-based control center at a greater distance or to carry out precise navigation, releasing buoys 6.3 to utilize satellite communication is more effective.

[0052] 2.1) When the water depth is large, since it is impossible to measure the velocity at the bottom using DVL (Depth-to-Voltage Linear Vibration), multiple conformal vibration sensors are used to capture the pulsating pressure field (waveform) generated when the ocean current flows over the surface of the carrier. Combined with a waveform-velocity database, the ocean current velocity vector is calculated in real time from the waveform. The specific formula is as follows: k = f(u;θ) Where, k: the full-field vibration spectrum data (amplitude, frequency, phase) measured by the conformal vibration sensor; u: Ocean current velocity vector; θ: State parameters, including the carrier's own propulsion speed vp, attitude angle ϕ, and water depth p.

[0053] At this point, the speed of the submersible relative to the water body is measured (relative speed), Vg = Vm + Vw.

[0054] Vg: Absolute velocity relative to the bottom Vm: Measured value, relative velocity Vw: Ocean current data.

[0055] Due to the complex water flow conditions within the water column and the influence of factors such as ocean currents, the velocity values ​​obtained from the water-tracking mode contain a certain degree of error and are inaccurate estimates. In this situation, using multiple conformal vibration sensors to measure ocean current velocity can supplement the velocity values ​​obtained from the DVL water-tracking mode. By comprehensively analyzing the velocity information obtained from both methods, the accuracy and reliability of submersible velocity measurement can be improved. For example, during deep-sea navigation, when DVL uses the water-tracking mode, combining it with ocean current velocity measurements from conformal vibration sensors can provide a more accurate understanding of the submersible's actual motion state.

[0056] 3) Entering and Maintaining Mooring: Upon reaching the preset location, the terrain-aided navigation system 1.6 scans and samples the terrain data within the preset area, simultaneously obtaining a waveform-velocity model database. After sampling, it returns to the designated mooring point and shuts off the thrusters 4.2. At this time, the submersible will drift with the current, while the navigation system 1.1, Doppler log 1.2, and terrain-aided navigation system 1.6, through motion sensing and terrain comparison, ensure that the submersible remains within the designated area. During this process, the thrusters and active sonar remain off, while the passive sonar receives external data and the calculation function is maintained, supplemented by intermittent terrain matching to correct the position, saving power and maintaining the submersible's status. When the controller 2.1 calculates that it has left the mooring range based on the navigation parameter input, it activates the terrain-aided navigation system 1.6 for confirmation. Once the database confirms that it has left the area, the thrusters 4.2 are activated to return to the preset mooring point. If the verification result is still within the mooring range, the sensor parameters are corrected. At regular intervals, the terrain-aided navigation system 1.6 corrects the inertial navigation system 1.1 to avoid cumulative errors. Upon reaching the preset location, the terrain-aided navigation system 1.6 activates, scanning and sampling the terrain data within the designated area and further refining the waveform-velocity model database. With the thrusters 4.2 shut off, the submersible drifts with the current, but by retaining the inertial navigation system 1.1, Doppler log 1.2, and terrain-aided navigation system 1.6, the submersible's motion and surrounding terrain features can be monitored in real time. Comparison with a preset range ensures the submersible remains within the designated area. During this process, shutting off the thrusters and active sonar reduces power consumption, while retaining the passive sonar to receive external data ensures the submersible's ability to perceive its surroundings. Calculation functions, supplemented by intermittent terrain matching to correct position, further improve positioning accuracy. When the controller 2.1, based on the input parameters from the inertial navigation system 1.1 and Doppler log 1.2, detects that the submersible may have strayed from its mooring range, it activates the terrain-aided navigation system 1.6 for confirmation. If the deviated area is verified, thrusters 4.2 are activated to return to the preset mooring point; if still within the mooring range, sensor parameters are corrected to improve measurement accuracy. Periodically, the terrain-aided navigation system 1.6 corrects the inertial navigation system 1.1, effectively avoiding accumulated errors caused by integration calculations and ensuring the submersible's positioning accuracy while moored. For example, during extended mooring periods, this correction mechanism ensures the submersible remains within the designated mooring area.

[0057] 4) Demoting: When the system needs to be detached for operations according to the preset task instructions or instructions issued via remote communication, the unmanned submersible will activate thrusters 4.2 and operation module 6.4 to perform the task. When the preset task instructions are reached or instructions are received via remote communication, the unmanned submersible needs to detach from its mooring state to perform the task. At this time, thrusters 4.2 are activated to provide power for the submersible to leave the mooring point and proceed to the work area. Simultaneously, operation module 6.4 is activated to perform corresponding operations according to specific task requirements, such as underwater observation, sampling, and retrieval. For example, in marine resource exploration tasks, operation module 6.4 can be activated to sample and analyze seabed minerals; in underwater environmental monitoring tasks, the sensors in operation module 6.4 can be used to monitor water quality, ecology, and other aspects.

[0058] The unmanned submersible mooring system of this invention achieves stable mooring in the marine environment through the coordinated operation of its subsystems. Its autonomous recovery capability allows the submersible to automatically return to a designated location after leaving the mooring area, improving the system's reliability and stability. This design is adaptable to various operational conditions, such as marine environmental monitoring, resource exploration, and military reconnaissance, meeting the needs of different missions and effectively solving the current problem of a lack of effective mooring methods for unmanned submersibles. It provides technical support for the widespread application of unmanned submersibles in the marine field.

[0059] Throughout the entire operation, the submersible's movements are primarily controlled by pre-set commands and underwater acoustic communication commands. Pre-set commands can be carefully planned and configured before mission execution, reducing the need for real-time communication during the mission. While underwater acoustic communication has a relatively low transmission rate, it offers superior stealth capabilities, making it difficult for the enemy to detect. This method greatly ensures the submersible's stealth performance, enabling it to perform missions safely and effectively in military and other fields where concealment is crucial. For example, during covert reconnaissance missions, using pre-set commands and underwater acoustic communication can prevent the submersible from revealing its location, increasing the mission's success rate.

[0060] By flexibly utilizing the terrain-assisted navigation system and limiting the mooring range, the problems of its sensitivity to terrain changes and complex data processing can be avoided, giving full play to its advantages of high accuracy and strong autonomy, and ensuring positioning accuracy in the moored state. In this invention, by limiting the mooring range, the application of the terrain-assisted navigation system is restricted to a relatively small area, reducing the impact of terrain changes on it.

[0061] By setting the mooring range, turning off the thrusters and active sonar, and reducing power consumption, the overall range pressure is reduced, ensuring stealth in the moored state.

[0062] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A mooring system for an unmanned submersible, characterized in that, include: The sensor acquisition system includes an inertial navigation system, a Doppler log, a depth sensor, a multibeam forward-looking sonar, a side-scan sonar, a terrain-aided navigation system, a GNSS receiver, and a conformal vibration sensor. The control system, connected to the sensor acquisition system, includes a controller for processing information transmitted by the sensors and generating control commands according to preset tasks and algorithms; A communication system, connected to the control system, includes underwater acoustic communication equipment and satellite communication equipment; the underwater acoustic communication equipment is used to realize underwater information interaction and communication, and the satellite communication equipment is used to realize data transmission with shore-based / mother ship; a propulsion system, connected to the control system, includes a propulsion motor and a propeller; the propeller is used to realize the submersible's navigation, maneuvering, and mooring operations; The conformal vibration sensors are multiple and are laid on the surface of the submersible to capture the velocity-dependent pulsating pressure field generated when ocean currents flow over the surface of the carrier, and to acquire full-field vibration spectrum data and waveform data. The navigation speed data is obtained by receiving signals transmitted by a GNSS receiver via satellite communication, or by obtaining navigation speed data through a Doppler log and inertial navigation system. A waveform-velocity database is then established by combining the waveform data.

2. The unmanned submersible mooring system according to claim 1, characterized in that, The sensor acquisition system: The inertial navigation system is used to acquire the speed, position, and attitude information of the submersible, and has autonomy and stealth capabilities; the Doppler log is used to provide speed information and assist in correcting the inertial navigation system, reducing the cumulative error of long-distance navigation. Depth sensors are used to provide depth information for submersibles; Multibeam forward-looking sonar is used to detect the area in front of the submersible in real time, forming an acoustic image of the fan-shaped area in front, and detecting obstacles in the range in advance. Side-scan sonar, deployed on the side of the hull, is used to acquire information about the surrounding environment and supplement the multibeam forward-looking sonar; terrain-aided navigation system is used to perform terrain matching in moored situations and provide a basis for the control system's decision-making; GNSS receiver, deployed on the buoy system, is used to receive satellite signals and realize navigation and positioning functions.

3. The unmanned submersible mooring system according to claim 1, characterized in that, The conformal vibration sensor establishes a waveform-velocity database in the following manner: While the submersible is in motion, waveform data is obtained through multiple conformal vibration sensors; navigation speed data is obtained by receiving signals transmitted by a GNSS receiver via satellite communication, and the relationship between waveform and speed in this area is analyzed to establish a waveform-speed database; or when the water depth is shallow, navigation speed data is obtained through a Doppler log and an inertial navigation system, and combined with the waveform data obtained from the conformal vibration sensors to establish a waveform-speed database.

4. The unmanned submersible mooring system according to claim 1, characterized in that, The controller in the control system calculates and analyzes the position, speed, attitude and environmental information transmitted by the sensor system using a preset algorithm, and generates the thruster speed control command and the servo motor angle control command.

5. The unmanned submersible mooring system according to claim 1, characterized in that, The underwater acoustic communication equipment in the communication system is an integrated system of underwater acoustic communication device, transducer, and hydrophone, which uses the characteristics of sound waves propagating in water to conduct communication; the satellite communication equipment establishes a communication link with satellites in Earth orbit by transmitting and receiving radio signals, thereby realizing long-distance data transmission with shore-based or mother ship bases.

6. The unmanned submersible mooring system according to claim 1, characterized in that, The propulsion system consists of a main thruster, an auxiliary thruster, and a vertical thruster, or multiple thrusters arranged at an angle to achieve 6 degrees of freedom of movement.

7. The unmanned submersible mooring system according to claim 1, characterized in that, Also includes: The energy system, connected to the propulsion system, control system, sensor acquisition system, and communication system, includes a power battery to provide energy for the entire mission. The support system, connected to the control system, includes a submersible structure, a submersible balancing system, a buoy system, and an operations module. The submersible structure provides hydrodynamic hull lines and equipment support frames. The submersible balancing system provides underwater buoyancy and adjusts the center of gravity. The buoy system serves as a working platform for the GNSS receiver and satellite communication equipment. The operations module is optional and can be installed according to mission requirements.

8. The unmanned submersible mooring system according to claim 7, characterized in that, The submersible in the support system adopts a streamlined shape design to reduce the resistance of the submersible when it travels in water and improves the navigation efficiency; the buoyancy balancing system controls the buoyancy of the submersible by adjusting the buoyancy device inside the submersible, so that it can maintain a stable suspended state in the water.

9. The unmanned submersible mooring system according to claim 7, characterized in that, The buoy system is equipped with a winch and cable, and after receiving instructions to deploy it to the sea surface, it serves as a working platform for GNSS receivers and satellite communication equipment; the operation module is optional according to mission requirements, including underwater cameras, various types of active and passive sonar, and robotic arms.

10. A control method for an unmanned submersible mooring system, characterized in that, Includes the following steps: S1. Navigate to the designated location: The target point is preset using latitude and longitude coordinates, and the mooring status is maintained within a certain range; the ship is fully submerged in water during the entire navigation process, and real-time position and attitude information is calculated using inertial navigation and Doppler log; surrounding obstacles are detected using multibeam forward-looking sonar, and depth information is provided by depth sensors. The controller receives the data from the sensor acquisition system, performs calculations and analysis according to preset algorithms, and realizes obstacle avoidance and path planning. S2. Navigation Position Correction and Long-Distance Communication: In safe waters or in emergency situations, buoys are released to achieve satellite navigation via GNSS receivers and long-distance communication via satellite communication equipment; during navigation, underwater acoustic communication equipment is used for most of the time, and communication is established via extremely low frequency / very low frequency. S2.1 When the water depth is large, multiple conformal vibration sensors capture the pulsating pressure field related to the flow velocity generated when the ocean current flows over the surface of the carrier. Combined with the waveform-velocity database, the ocean current velocity vector is calculated in real time from the waveform. S3. Entering and maintaining mooring: After reaching the preset point, the terrain-assisted navigation system scans and samples the terrain data within the preset range, and obtains the waveform-velocity model database at the same time. After sampling is completed, the submersible returns to the designated mooring point, shuts off the thrusters, and retains the inertial navigation system, Doppler log, and terrain-assisted navigation system. Through motion sensing and terrain comparison, the submersible is ensured to remain in the designated area. When the controller calculates that it has left the mooring range based on the navigation parameters, it activates the terrain-assisted navigation system for confirmation. Once the database verifies the area where it has left the mooring range, it activates the thrusters to return to the preset mooring point. If the verification results are still within the mooring range, the sensor parameters are corrected; at regular intervals, the inertial navigation system is corrected through the terrain-aided navigation system to avoid cumulative errors. S4. Demoting from mooring: When the system needs to be demoted to perform operations according to the preset task instructions at the designated time, or according to instructions issued by remote communication, the thrusters and operation modules are activated to perform the task.

Images