Autonomous underwater vehicle autonomous back-to-cabin method and autonomous back-to-cabin system

Abstract

The invention discloses an autonomous underwater vehicle autonomous back-to-cabin method and an autonomous back-to-cabin system. The autonomous back-to-cabin method comprises the following steps: S1, enabling an autonomous underwater vehicle and a large vehicle to be equal in depth; s2, enabling the autonomous underwater vehicle to approach the large vehicle; s3, enabling the course of the autonomous underwater vehicle to be consistent with the navigation of the large-scale vehicle, and enabling the bow part of the autonomous underwater vehicle to face a cabin door of the large-scale vehicle; s4, enabling the connecting line of the stem and the stern of the autonomous underwater vehicle to coincide with the connecting line of the stem and the stern of the large vehicle; and S5, finely adjusting the attitude of the autonomous underwater vehicle to enable the autonomous underwater vehicle to enter the interior of the large-scale vehicle through the cabin door of the large-scale vehicle so as to realize autonomous back-to-cabin of the autonomous underwater vehicle.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology, and in particular to an autonomous underwater vehicle autonomous return method and autonomous return system. Background Technology

[0002] Autonomous underwater vehicles (AUVs) play a vital role in underwater security, search and rescue, and ocean exploration due to their high maneuverability, navigation accuracy, and endurance. To extend their operational range and duration, AUVs are typically transported to designated operational areas by large carriers, from which they are then controlled to extend beyond their designated areas to perform tasks. After a certain period, the AUV must return underwater to the carrier for recharging and data transmission before continuing its mission. The large carrier can also be a seabed-mounted, long-term operational workstation or deep-sea space station.

[0003] Because the latitude and longitude coordinates output by the autonomous underwater vehicle's (AUV) navigation system have some errors after a certain period of underwater navigation, and the latitude and longitude coordinates output by the large carrier's navigation system also have some errors, docking and return to the large carrier cannot be achieved using only navigation data from both. The current solution mainly involves using an ultra-short baseline positioning system to measure the AUV's three-dimensional relative position to the large carrier in real time, and using this information to control the AUV to slowly approach it. When the distance meets the optical positioning conditions, an optical imaging positioning system is used to complete the final positioning and alignment, controlling the AUV to complete the final docking and return to the carrier.

[0004] In some situations, long baseline positioning systems are used instead of ultra-short baseline positioning systems to ensure positioning accuracy. Existing methods heavily rely on the positioning accuracy of ultra-short baseline positioning systems. In shallow water or environments with complex underwater topography, ultra-short baseline positioning systems may experience increased azimuth estimation errors due to multipath reflection interference, resulting in significant jumps in relative position measurements. These jumps can prevent the autonomous underwater vehicle's return-to-base control algorithm from converging, leading to mission failure.

[0005] The long baseline positioning system requires the deployment of several additional base station beacons, and precise acquisition of their location information is essential, complicating the entire process and increasing costs. Furthermore, it cannot completely eliminate the problem of reduced positioning accuracy due to multipath reflections. Summary of the Invention

[0006] One object of the present invention is to provide an autonomous return method and system for an autonomous underwater vehicle (AUV), wherein, without utilizing ultra-short baseline positioning systems and long baseline positioning systems, the autonomous return method of the present invention can complete the task of returning the AUV to the cabin of a large carrier using only the depth gauge, underwater acoustic communication device, inertial navigation system, forward-viewing sonar, and optical imaging system onboard the AUV itself. The autonomous return method not only reduces the cost of return but also reduces the requirements for the return operation environment, has stronger environmental adaptability, and is particularly suitable for performing any return operation in complex aquatic environments.

[0007] One objective of this invention is to provide an autonomous underwater vehicle (AUV) return method and system, wherein the AUV return process is divided into three stages: long-range control, medium-range control, and short-range control. Thus, the autonomous return method of this invention can balance return speed and return accuracy, ensuring that the return mission is completed efficiently and accurately, thereby improving the operational reliability of the AUV.

[0008] One objective of this invention is to provide an autonomous underwater vehicle (AUV) return method and system. In the long-range control phase, the autonomous return method utilizes data from an inertial navigation system and an underwater acoustic communication device for positioning. In the mid-range control phase, it utilizes forward-viewing sonar for positioning. In the close-range control phase, it utilizes an optical imaging system for positioning. This approach achieves several advantages: firstly, each phase enables automated control with feedback and adaptive capabilities, addressing water flow disturbances and slight deviations of the large vehicle, thus ensuring successful return. Secondly, using different systems for precise positioning in different phases reduces algorithm complexity and eliminates the need for complex computational models, thereby minimizing the computational resources required by the AUV and facilitating engineering implementation and widespread adoption. Furthermore, in the mid-range control phase, positioning using forward-viewing sonar effectively identifies obstacles, mitigating collision risks during return. In the close-range control phase, positioning using optical imaging system data provides better docking accuracy, preventing equipment damage due to docking deviations. According to one aspect of the present invention, the present invention provides a method for autonomous return of an autonomous underwater vehicle, wherein the autonomous return method includes the following steps: S1, based on the depth data h output by the depth gauge of the autonomous underwater vehicle and the depth data h1 of the large vehicle output by the underwater acoustic communication device, make the autonomous underwater vehicle and the large vehicle have the same depth. S2, based on the latitude and longitude data lat and lon output by the inertial navigation system of the autonomous underwater vehicle and the latitude and longitude data lat1 and lon1 output by the underwater acoustic communication device of the large carrier, calculate the horizontal slant distance D and azimuth Br of the autonomous underwater vehicle relative to the large carrier, so that the autonomous underwater vehicle moves closer to the large carrier. S3, based on the heading data yaw output by the inertial navigation system of the autonomous underwater vehicle and the heading data yaw1 output by the underwater acoustic communication device of the large carrier, the heading of the autonomous underwater vehicle and the heading of the large carrier are aligned, and the bow of the autonomous underwater vehicle faces the hatch of the large carrier. S4. Based on the distance R and bearing P of the center point of the large carrier output by the forward view image sonar of the autonomous underwater vehicle, make the bow-stern line of the autonomous underwater vehicle coincide with the bow-stern line of the large carrier. S5. Based on the center points X and Y of the hatch of the large carrier output by the optical imaging system of the autonomous underwater vehicle, the attitude of the autonomous underwater vehicle is finely adjusted so that the autonomous underwater vehicle enters the interior of the large carrier through the hatch of the large carrier.

[0009] According to one embodiment of the present invention, in step S2, when the autonomous underwater vehicle (AUV) approaches the large carrier, the AUV is allowed to periodically communicate with the large carrier via underwater acoustics, receive the longitude data lat1 and latitude data lon1 of the large carrier, and then combine its own longitude data lat and latitude data lon to calculate the horizontal slant range D and azimuth Br of the AUV relative to the large carrier.

[0010] According to one embodiment of the present invention, in step S3, when the horizontal slant distance D is less than or equal to 500 meters and the bearing Br is less than or equal to 15 degrees, the heading of the autonomous underwater vehicle (AUV) is adjusted. The AUV periodically communicates with the large carrier to obtain the heading yaw1 of the large carrier and slowly adjusts its own heading yaw. When the heading yaw and heading yaw1 satisfy... At that time, the course of the autonomous underwater vehicle is consistent with the course of the large carrier.

[0011] According to one embodiment of the present invention, in step S4, while the autonomous underwater vehicle (AUV) is maintaining its course, it periodically engages in underwater acoustic communication with the large carrier to calculate the horizontal slant range D and bearing Br of the AUV relative to the large carrier. When the horizontal slant range is less than or equal to 150 meters, the forward-viewing image sonar is activated to detect the distance R and bearing P of the large carrier relative to the AUV. Based on the current bearing P, the course of the AUV is adjusted. At that time, the bow-stern line of the autonomous underwater vehicle coincides with the bow-stern line of the large carrier.

[0012] According to one embodiment of the present invention, in step S5, while the autonomous underwater vehicle is maintaining its course, when the forward-view imaging sonar detects that the horizontal slant distance D is less than or equal to 2 meters, the optical imaging system is activated to detect the hatch of the large carrier and obtain the hatch center points X and Y.

[0013] According to another aspect of the present invention, the present invention further provides an autonomous underwater vehicle autonomous return system, comprising: The depth control module is used to output action commands based on the depth data h output by the depth gauge of the autonomous underwater vehicle and the depth data h1 of the large carrier output by the underwater acoustic communication device, so that the autonomous underwater vehicle is at the same depth as the large carrier. The distance and bearing calculation module is used to calculate the horizontal slant distance D and bearing Br of the autonomous underwater vehicle relative to the large carrier based on the latitude and longitude data lat and lon output by the inertial navigation system of the autonomous underwater vehicle and the latitude and longitude data lat1 and lon1 output by the underwater acoustic communication device, and output action commands to make the autonomous underwater vehicle move closer to the large carrier. The heading adjustment module is used to output action commands based on the heading data yaw output by the inertial navigation system of the autonomous underwater vehicle and the heading data yaw1 output by the underwater acoustic communication device of the large carrier, so that the heading of the autonomous underwater vehicle is consistent with the heading of the large carrier, and the bow of the autonomous underwater vehicle is facing the hatch of the large carrier. It is also used to output action commands based on the distance R and bearing P of the center point of the large carrier output by the forward view image sonar of the autonomous underwater vehicle, so that the bow-stern line of the autonomous underwater vehicle coincides with the bow-stern line of the large carrier. The attitude fine-tuning module is used to output action commands to fine-tune the attitude of the autonomous underwater vehicle based on the center points X and Y of the hatch of the large carrier output by the optical imaging system of the autonomous underwater vehicle, so that the autonomous underwater vehicle can enter the interior of the large carrier through the hatch of the large carrier.

[0014] According to one embodiment of the present invention, when the autonomous underwater vehicle (AUV) approaches the large carrier, the AUV is allowed to periodically conduct underwater acoustic communication with the large carrier. The distance and bearing calculation module calculates the horizontal slant range D and bearing Br of the AUV relative to the large carrier based on the latitude and longitude data lat and lon output by the inertial navigation system of the AUV and the latitude and longitude data lat1 and lon1 output by the underwater acoustic communication device.

[0015] According to one embodiment of the present invention, when the horizontal slant distance D is less than or equal to 500 meters and the bearing Br is less than or equal to 15 degrees, the heading adjustment module begins to adjust the heading of the autonomous underwater vehicle. The autonomous underwater vehicle periodically engages in underwater acoustic communication with the large carrier to obtain the heading yaw1 of the large carrier, and slowly adjusts its own heading yaw. When the heading yaw and heading yaw1 satisfy... At that time, the course of the autonomous underwater vehicle is consistent with the course of the large carrier.

[0016] According to one embodiment of the present invention, during the course of the autonomous underwater vehicle (AUV) maintaining its course, it periodically engages in underwater acoustic communication with the large carrier to calculate the horizontal slant range D and bearing Br of the AUV relative to the large carrier. When the horizontal slant range is less than or equal to 150 meters, the forward-viewing image sonar is activated to detect the distance R and bearing P of the large carrier relative to the AUV. Based on the current bearing P, the course adjustment module adjusts the course of the AUV. At that time, the bow-stern line of the autonomous underwater vehicle coincides with the bow-stern line of the large carrier.

[0017] According to one embodiment of the present invention, when the autonomous underwater vehicle maintains its course and the forward-view imaging sonar detects that the horizontal slant distance D is less than or equal to 2 meters, the optical imaging system is activated to detect the hatch of the large carrier and obtain the hatch center point X and Y. Subsequently, the attitude fine-tuning module fine-tunes the attitude of the autonomous underwater vehicle based on the hatch center point X and Y, so that the autonomous underwater vehicle can enter the interior of the large carrier through the hatch. Attached Figure Description

[0018] Figure 1 It is a system block diagram consisting of an autonomous underwater vehicle and a large carrier.

[0019] Figure 2 This is a block diagram of the navigation control software used to control the autonomous underwater vehicle to return to its cabin.

[0020] Figure 3 This is a frontal view image of the sonar of the autonomous underwater vehicle.

[0021] Figure 4 This is an image showing the imaging effect of the optical imaging system of the autonomous underwater vehicle.

[0022] Figure 5 This is a timing diagram of the operation of the system consisting of the autonomous underwater vehicle and the large carrier.

[0023] Figure 6 This is a flowchart of the system consisting of the autonomous underwater vehicle and the large carrier.

[0024] Figure 7 This is a flowchart of the autonomous underwater vehicle's autonomous return-to-capsule method.

[0025] Figure 8 This is a block diagram of the autonomous underwater vehicle's autonomous return system. Detailed Implementation

[0026] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0027] The terminology used in the following embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to also include expressions such as “one or more,” unless the context clearly indicates otherwise. It should also be understood that in the following embodiments of this application, “at least one” and “one or more” refer to one, two, or more than two. The term “and / or” is used to describe the relationship between related objects, indicating that three relationships may exist; for example, A and / or B can indicate: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character “ / ” generally indicates that the preceding and following related objects are in an “or” relationship.

[0028] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0029] Reference Appendix Figures 1 to 7 The autonomous underwater vehicle 10 is equipped with a depth gauge 11, an underwater acoustic communication device 12, an inertial navigation system 13, a forward-viewing imaging sonar 14, an optical imaging system 15, and a thruster and servo motor 16. It is also equipped with navigation control software 17, which is used not only to control the navigation of the autonomous underwater vehicle 10, but also to control the autonomous underwater vehicle 10 to automatically return to the interior of the large carrier 20, that is, to realize the automatic return of the autonomous underwater vehicle 10 to its cabin.

[0030] During the autonomous return process, the navigation control software 17, as the control center of the return mission, is responsible for receiving data output from the various payload devices of the autonomous underwater vehicle 10 (the depth gauge 11, the underwater acoustic communication device 12, the inertial navigation system 13, the forward-view imaging sonar 14, and the optical imaging system 15), performing data fusion processing and calculation to obtain the control parameters of the thrusters and servo motors 16 of the autonomous underwater vehicle 10, and issuing action commands to make the autonomous underwater vehicle 10 move according to the set trajectory, so as to achieve the smooth return of the autonomous underwater vehicle 10.

[0031] Specifically, firstly, the navigation control software 17 receives the depth data h output by the depth gauge 11 of the autonomous underwater vehicle 10, and combines it with the depth data h1 of the large carrier 20 output by the underwater acoustic communication device 12, and outputs an action command through a depth control module 31 of the autonomous return system 30, so that the autonomous underwater vehicle 10 and the large carrier 20 are at the same depth.

[0032] Secondly, the navigation control software 17 receives the latitude and longitude data lat and lon output by the inertial navigation system 13 of the autonomous underwater vehicle 10, and calculates the horizontal slant distance D and bearing Br of the autonomous underwater vehicle 10 relative to the large carrier 20 in a distance and bearing calculation module 32 of the autonomous return system 30, combined with the latitude and longitude data lat1 and lon1 output by the underwater acoustic communication device 12, and outputs an action command to make the autonomous underwater vehicle 10 approach the large carrier 20.

[0033] Third, the navigation control software 17 receives the heading data yaw output by the inertial navigation system 13 of the autonomous underwater vehicle 10, and combines it with the heading data yaw1 of the large carrier 20 output by the underwater acoustic communication device 12. Through a heading adjustment module 33 of the autonomous return system 30, the software outputs an action command to make the heading of the autonomous underwater vehicle 10 consistent with the heading of the large carrier 20, and the bow of the autonomous underwater vehicle 10 faces the hatch of the large carrier 20.

[0034] Fourth, the navigation control software 17 receives the center point distance R and bearing P of the large carrier 20 output by the forward-view imaging sonar 14 of the autonomous underwater vehicle 10, and outputs an action command through the heading adjustment module 33 of the autonomous return system 30, so that the bow-stern line of the autonomous underwater vehicle 10 coincides with the bow-stern line of the large carrier 20.

[0035] Fifth, the navigation control software 17 receives the center points X and Y of the hatch of the large carrier 20 output by the optical imaging system 15 of the autonomous underwater vehicle 10, and outputs action commands through an attitude fine-tuning module 34 of the autonomous return system 30, so that the autonomous underwater vehicle 10 can be received and its navigation attitude fine-tuned, and it can slowly navigate through the hatch of the large carrier 20 and enter the interior of the large carrier 20, thereby realizing the autonomous return of the autonomous underwater vehicle 10.

[0036] Unlike existing technologies, in this invention, without utilizing ultra-short baseline positioning systems and long baseline positioning systems, the autonomous underwater vehicle 10 can complete the task of returning to the cabin of the large carrier 20 using only the depth gauge 11, the underwater acoustic communication device 12, the inertial navigation system 13, the forward-view imaging sonar 14, and the optical imaging system 15 mounted on its own. This not only helps reduce the cost of returning to the cabin but also reduces the requirements for the return operation environment, making it more environmentally adaptable and particularly suitable for performing any return operation in complex aquatic environments.

[0037] The underwater acoustic communication device 12 of the autonomous underwater vehicle 10 enables the large carrier 20 to periodically send messages to the autonomous underwater vehicle 10, transmitting information of the large carrier 20, mainly including depth data h1, heading data yaw1, longitude data lat1, and latitude data lon1.

[0038] Reference Appendix Figure 3 The forward-view imaging sonar 14 of the autonomous underwater vehicle 10 includes an imaging module and a target detection module. The imaging module is based on the multi-beam imaging principle and emits acoustic signals forward. It uses a receiving beamforming algorithm and matched filtering to achieve two-dimensional acoustic imaging of a certain width in front of the forward-view imaging sonar 14. The target detection module performs center detection on the bright spot of the large carrier 20 in the two-dimensional acoustic image based on the two-dimensional acoustic image results and outputs the center point distance R and azimuth P.

[0039] Reference Appendix Figure 4 The optical imaging system 15 of the autonomous underwater vehicle 10 consists of an underwater camera installed directly in front of the bow of the autonomous underwater vehicle 10 and light source detection software. The underwater camera images four light sources installed above, below, to the left and right of the hatch of the large carrier 20 at close range. The light source detection software detects the center points X and Y of the four light sources based on the imaging results. This center is the center of the hatch of the large carrier 20 and is output to the navigation control software 17.

[0040] Reference Appendix Figure 5 and Figure 6 In this invention, the return-to-capsule process of the autonomous underwater vehicle 10 is divided into a long-range control phase, a medium-range control phase, and a short-range control phase. The long-range control phase occurs when the horizontal distance between the autonomous underwater vehicle 10 and the large carrier 20 is between 150 meters and 2000 meters. The medium-range control phase occurs when the horizontal distance between the autonomous underwater vehicle 10 and the large carrier 20 is between 2 meters and 150 meters. The short-range control phase occurs when the horizontal distance between the autonomous underwater vehicle 10 and the large carrier 20 is less than 2 meters.

[0041] During operation, the autonomous underwater vehicle 10 approaches the large carrier 20, periodically engaging in underwater acoustic communication with the large carrier 20 to obtain the longitude data lat1 and latitude data lon1 of the large carrier 20. Combining this with the autonomous underwater vehicle 10's own longitude data lat and latitude data lon, the horizontal slant range D and azimuth Br of the autonomous underwater vehicle 10 relative to the large carrier 20 are calculated.

[0042] When the horizontal slant distance D between the autonomous underwater vehicle 10 and the large carrier 20 is no greater than 500 meters and the bearing Br is no greater than 15 degrees, it is considered that the autonomous underwater vehicle 10 and the large carrier 20 are roughly aligned in course, and then the heading of the autonomous underwater vehicle 10 begins to be adjusted. Based on the heading yaw1 of the large carrier 20 obtained by the underwater acoustic communication device 12, the autonomous underwater vehicle 10 slowly adjusts its own heading yaw. When the angle is no greater than 2 degrees, the course of the autonomous underwater vehicle 10 and the large carrier 20 is considered to be finely aligned.

[0043] The autonomous underwater vehicle 10 maintains its course and periodically communicates with the large carrier 20 via underwater acoustics to calculate the horizontal slant range D and bearing Br of the autonomous underwater vehicle 10 relative to the large carrier 20. When the horizontal slant range D of the autonomous underwater vehicle 10 relative to the large carrier 20 is no greater than 150 meters, the autonomous underwater vehicle 10 activates its forward-viewing image sonar 14 to detect the distance R and bearing P of the large carrier 20 relative to the autonomous underwater vehicle 10. Based on the current bearing P, the autonomous underwater vehicle 10 adjusts its course until... A deviation of no more than 1 degree is considered a precise alignment of the autonomous underwater vehicle 10 and the large carrier 20, meaning that the bow-stern line of the autonomous underwater vehicle 10 and the bow-stern line of the large carrier 20 have coincided.

[0044] The autonomous underwater vehicle 10 maintains its course. When the forward-view imaging sonar 14 detects that the horizontal slant distance D between the autonomous underwater vehicle 10 and the large carrier 20 is no greater than 2 meters, the autonomous underwater vehicle 10 activates the optical imaging system 15 to image and detect four light sources above, below, left, and right of the hatch of the large carrier 20 to obtain the center points X and Y of the hatch. Based on the center points X and Y of the hatch, the autonomous underwater vehicle 10's navigation attitude is finely adjusted so that the autonomous underwater vehicle 10 slowly sails through the hatch of the large carrier 20 and enters the interior of the large carrier 20.

[0045] In other words, in this invention, the return-to-capsule process of the autonomous underwater vehicle 10 is divided into three stages: long-range control, medium-range control, and short-range control. In this way, the invention can take into account both return-to-capsule speed and return-to-capsule accuracy, ensuring that the return-to-capsule mission is completed efficiently and accurately, which is conducive to improving the operational reliability of the autonomous underwater vehicle 10.

[0046] Specifically, in the long-range control phase, positioning is achieved using data provided by the inertial navigation system 13 and the underwater acoustic communication device 12; in the mid-range control phase, positioning is achieved using the forward-viewing imaging sonar 14; and in the close-range control phase, positioning is achieved using the optical imaging system 15. This approach allows for automated control at each stage, while also providing feedback and adaptive capabilities to handle water flow disturbances and slight deviations of the large carrier 20, ensuring the successful completion of the return mission. Furthermore, using different systems for precise positioning at different stages reduces algorithm complexity and eliminates the need for complex computational models, thus requiring less computing power from the autonomous underwater vehicle 10 and facilitating engineering implementation and widespread adoption. Additionally, positioning using data from the forward-viewing imaging sonar 14 in the mid-range control phase effectively identifies obstacles, avoiding collision risks during the return process. In the close-range control phase, positioning using data from the optical imaging system 15 provides better docking accuracy, preventing equipment damage due to docking deviations.

[0047] Reference Appendix Figure 7 According to one aspect of the present invention, the present invention provides an autonomous return method for the autonomous underwater vehicle 10, wherein the autonomous return method includes the steps of: S1, based on the depth data h output by the depth gauge 11 of the autonomous underwater vehicle 10 and the depth data h1 of the large carrier 20 output by the underwater acoustic communication device 12, the autonomous underwater vehicle 10 and the large carrier 20 are made to be at the same depth. S2, based on the latitude and longitude data lat and lon output by the inertial navigation system 13 of the autonomous underwater vehicle 10 and the latitude and longitude data lat1 and lon1 output by the underwater acoustic communication device 12 of the large carrier 20, the horizontal slant distance D and azimuth Br of the autonomous underwater vehicle 10 relative to the large carrier 20 are calculated, so that the autonomous underwater vehicle 10 moves closer to the large carrier 20. S3, based on the heading data yaw output by the inertial navigation system 13 of the autonomous underwater vehicle 10 and the heading data yaw1 of the large carrier 20 output by the underwater acoustic communication device 12, the heading of the autonomous underwater vehicle 10 is made consistent with the heading of the large carrier 20, and the bow of the autonomous underwater vehicle 10 faces the hatch of the large carrier 20. S4, based on the distance R and bearing P of the center point of the large carrier 20 output by the forward-view image sonar 14 of the autonomous underwater vehicle 10, make the bow-stern line of the autonomous underwater vehicle 10 coincide with the bow-stern line of the large carrier 20. S5, based on the center points X and Y of the hatch of the large carrier 20 output by the optical imaging system 15 of the autonomous underwater vehicle 10, the attitude of the autonomous underwater vehicle 10 is finely adjusted so that the autonomous underwater vehicle 10 enters the interior of the large carrier 20 through the hatch of the large carrier 20.

[0048] Compared with existing technologies, without utilizing ultra-short baseline positioning systems and long baseline positioning systems, the autonomous return method of the present invention can complete the task of returning the autonomous underwater vehicle 10 to the cabin of the large carrier 20 using only the depth gauge 11, the underwater acoustic communication device 12, the inertial navigation system 13, the forward-view imaging sonar 14, and the optical imaging system 15 mounted on the autonomous underwater vehicle 10 itself. The autonomous return method not only reduces the cost of return but also reduces the requirements for the return operation environment, has stronger environmental adaptability, and is particularly suitable for performing any return operation in complex aquatic environments.

[0049] Preferably, in step S2, when the autonomous underwater vehicle 10 approaches the large carrier 20, the autonomous underwater vehicle 10 is allowed to periodically communicate with the large carrier 20 via underwater acoustics, receive the longitude data lat1 and latitude data lon1 of the large carrier 20, and then combine its own longitude data lat and latitude data lon to calculate the horizontal slant range D and azimuth Br of the autonomous underwater vehicle 10 relative to the large carrier 20.

[0050] Preferably, in step S3, when the horizontal slant distance D is less than or equal to 500 meters and the bearing Br is less than or equal to 15 degrees, the heading of the autonomous underwater vehicle 10 is adjusted. The autonomous underwater vehicle 10 periodically communicates with the large carrier 20 via underwater acoustics to obtain the heading yaw1 of the large carrier 20, and slowly adjusts its own heading yaw. When the heading yaw and heading yaw1 satisfy... At that time, the heading of the autonomous underwater vehicle 10 is consistent with the heading of the large carrier 20.

[0051] Preferably, in step S4, while the autonomous underwater vehicle 10 maintains its course, it periodically engages in underwater acoustic communication with the large carrier 20 to calculate the horizontal slant range D and bearing Br of the autonomous underwater vehicle 10 relative to the large carrier 20. When the horizontal slant range is less than or equal to 150 meters, the forward-viewing image sonar 14 is activated to detect the distance R and bearing P of the large carrier 20 relative to the autonomous underwater vehicle 10. Based on the current bearing P, the course of the autonomous underwater vehicle 10 is adjusted. At that time, the bow-stern line of the autonomous underwater vehicle 10 coincides with the bow-stern line of the large carrier 20.

[0052] Preferably, in step S5, while the autonomous underwater vehicle 10 is maintaining its course, when the forward-view imaging sonar 14 detects that the horizontal slant distance D is less than or equal to 2 meters, the optical imaging system 15 is activated to detect the hatch of the large carrier 20 and obtain the hatch center point X and Y.

[0053] In other words, in this invention, the return-to-capsule process of the autonomous underwater vehicle 10 is divided into three stages: long-range control, medium-range control, and short-range control. In this way, the autonomous return-to-capsule method of this invention can take into account both return-to-capsule speed and return-to-capsule accuracy, ensuring that the return-to-capsule mission is completed efficiently and accurately, which is conducive to improving the operational reliability of the autonomous underwater vehicle. Specifically, in the long-range control phase, the autonomous return method uses data provided by the inertial navigation system 13 and the underwater acoustic communication device 12 for positioning. In the mid-range control phase, the autonomous return method uses the forward-viewing imaging sonar 14 for positioning. In the close-range control phase, the autonomous return method uses the optical imaging system 15 for positioning. In this way, on the one hand, each phase can achieve automated control, while having feedback and adaptive capabilities, which can cope with water flow disturbances and slight deviations of the large carrier 20, which is conducive to ensuring the smooth completion of the return mission. On the other hand, using different systems for different phases to achieve precise positioning has low algorithm complexity and does not require complex calculation models, thus consuming less computing resources of the autonomous underwater vehicle 10, which is convenient for engineering implementation and promotion. Furthermore, in the mid-range control phase, positioning using data provided by the forward-viewing imaging sonar 14 can effectively identify obstacles and avoid collision risks during the return process. In the close-range control phase, positioning using data provided by the optical imaging system 15 has better docking accuracy and avoids equipment damage caused by docking deviations.

[0054] Reference Appendix Figure 8According to another aspect of the present invention, the present invention further provides an autonomous underwater vehicle autonomous return system 30, which includes the depth control module 31, the distance and bearing calculation module 32, the heading adjustment module 33, and the attitude fine-tuning module 34, wherein the depth control module 31 is used to output action commands based on the depth data h output by the depth gauge 11 of the autonomous underwater vehicle 10 and the depth data h1 of the large carrier 20 output by the underwater acoustic communication device 12, so that the autonomous underwater vehicle 10 returns to its designated position. The large transport vehicle 20 is at a constant depth, wherein the distance and bearing calculation module 32 is used to calculate the horizontal slant range D and bearing Br of the autonomous underwater vehicle 10 relative to the large transport vehicle 20 based on the latitude and longitude data lat and lon output by the inertial navigation system 13 of the autonomous underwater vehicle 10 and the latitude and longitude data lat1 and lon1 of the large transport vehicle 20 output by the underwater acoustic communication device 12, and outputs an action command to make the autonomous underwater vehicle 10 approach the large transport vehicle 20, wherein the heading The adjustment module 33 is used to output action commands based on the heading data yaw output by the inertial navigation system 13 of the autonomous underwater vehicle 10 and the heading data yaw1 of the large carrier 20 output by the underwater acoustic communication device 12, so that the heading of the autonomous underwater vehicle 10 is consistent with the heading of the large carrier 20, and the bow of the autonomous underwater vehicle 10 faces the hatch of the large carrier 20. It is also used to adjust the heading based on the heading data yaw1 of the forward-view imaging sonar 14 of the autonomous underwater vehicle 10. The center point distance R and bearing P of the autonomous underwater vehicle 10 are used to output action commands to make the bow-stern line of the autonomous underwater vehicle 10 coincide with the bow-stern line of the large carrier 20. The attitude fine-tuning module 34 is used to fine-tune the attitude of the autonomous underwater vehicle 10 based on the center point X and Y of the hatch of the large carrier 20 output by the optical imaging system 15 of the autonomous underwater vehicle 10, so that the autonomous underwater vehicle 10 enters the interior of the large carrier 20 through the hatch.

[0055] Compared with existing technologies, without utilizing ultra-short baseline positioning systems and long baseline positioning systems, the autonomous return system 30 of the present invention can complete the task of returning the autonomous underwater vehicle 10 to the cabin of the large carrier 20 using only the depth gauge 11, the underwater acoustic communication device 12, the inertial navigation system 13, the forward-view imaging sonar 14, and the optical imaging system 15 mounted on the autonomous underwater vehicle 10 itself. The autonomous return system 30 not only reduces the cost of return but also reduces the requirements for the return operation environment, has stronger environmental adaptability, and is particularly suitable for performing any return operation in complex aquatic environments.

[0056] Preferably, when the autonomous underwater vehicle 10 approaches the large carrier 20, the autonomous underwater vehicle 10 is allowed to periodically conduct underwater acoustic communication with the large carrier 20. The distance and bearing calculation module 32 calculates the horizontal slant range D and bearing Br of the autonomous underwater vehicle 10 relative to the large carrier 20 based on the latitude and longitude data lat and lon output by the inertial navigation system 13 of the autonomous underwater vehicle 10 and the latitude and longitude data lat1 and lon1 of the large carrier 20 output by the underwater acoustic communication device 12.

[0057] Preferably, when the horizontal slant distance D is less than or equal to 500 meters and the bearing Br is less than or equal to 15 degrees, the heading adjustment module 33 begins to adjust the heading of the autonomous underwater vehicle 10. The autonomous underwater vehicle 10 periodically communicates with the large carrier 20 via underwater acoustics to obtain the heading yaw1 of the large carrier 20, and slowly adjusts its own heading yaw. When the heading yaw and heading yaw1 satisfy... At that time, the heading of the autonomous underwater vehicle 10 is consistent with the heading of the large carrier 20.

[0058] Preferably, during the course maintenance of the autonomous underwater vehicle 10, it periodically engages in underwater acoustic communication with the large carrier 20 to calculate the horizontal slant range D and bearing Br of the autonomous underwater vehicle 10 relative to the large carrier 20. When the horizontal slant range is less than or equal to 150 meters, the forward-viewing image sonar 14 is activated to detect the distance R and bearing P of the large carrier 20 relative to the autonomous underwater vehicle 10. Based on the current bearing P, the course adjustment module 33 adjusts the course of the autonomous underwater vehicle 10. At that time, the bow-stern line of the autonomous underwater vehicle 10 coincides with the bow-stern line of the large carrier 20.

[0059] Preferably, during the course of the autonomous underwater vehicle 10, when the forward-view imaging sonar 14 detects a horizontal slant distance D of less than or equal to 2 meters, the optical imaging system 15 is activated to detect the hatch of the large carrier 20 and obtain the hatch center points X and Y. Subsequently, the attitude fine-tuning module 34 fine-tunes the attitude of the autonomous underwater vehicle 10 based on the hatch center points X and Y, so that the autonomous underwater vehicle 10 can enter the interior of the large carrier 20 through the hatch.

[0060] The above descriptions are merely embodiments of the invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of this invention, and these should also be considered within the scope of protection of this invention. These modifications and improvements will not affect the effectiveness of the invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for autonomous return to the capsule of an autonomous underwater vehicle, characterized in that, The autonomous return-to-capsule method includes the following steps: S1, based on the depth data h output by the depth gauge of the autonomous underwater vehicle and the depth data h1 of the large vehicle output by the underwater acoustic communication device, make the autonomous underwater vehicle and the large vehicle have the same depth. S2, based on the latitude and longitude data lat and lon output by the inertial navigation system of the autonomous underwater vehicle and the latitude and longitude data lat1 and lon1 output by the underwater acoustic communication device of the large carrier, calculate the horizontal slant distance D and azimuth Br of the autonomous underwater vehicle relative to the large carrier, so that the autonomous underwater vehicle moves closer to the large carrier. S3, based on the heading data yaw output by the inertial navigation system of the autonomous underwater vehicle and the heading data yaw1 output by the underwater acoustic communication device of the large carrier, the heading of the autonomous underwater vehicle and the heading of the large carrier are aligned, and the bow of the autonomous underwater vehicle faces the hatch of the large carrier. S4. Based on the distance R and bearing P of the center point of the large carrier output by the forward view image sonar of the autonomous underwater vehicle, make the bow-stern line of the autonomous underwater vehicle coincide with the bow-stern line of the large carrier. S5. Based on the center points X and Y of the hatch of the large carrier output by the optical imaging system of the autonomous underwater vehicle, the attitude of the autonomous underwater vehicle is finely adjusted so that the autonomous underwater vehicle enters the interior of the large carrier through the hatch of the large carrier.

2. The autonomous return method according to claim 1, wherein in step S2, when the autonomous underwater vehicle approaches the large carrier, the autonomous underwater vehicle is allowed to periodically conduct underwater acoustic communication with the large carrier, receive the longitude data lat1 and latitude data lon1 of the large carrier, and then combine its own longitude data lat and latitude data lon to calculate the horizontal slant range D and bearing Br of the autonomous underwater vehicle relative to the large carrier.

3. The autonomous return method according to claim 2, wherein in step S3, when the horizontal slant distance D is less than or equal to 500 meters and the bearing Br is less than or equal to 15 degrees, the heading of the autonomous underwater vehicle is adjusted, the autonomous underwater vehicle periodically communicates with the large carrier to obtain the heading yaw1 of the large carrier, and slowly adjusts its own heading yaw, until the heading yaw and heading yaw1 satisfy the following conditions. At that time, the course of the autonomous underwater vehicle is consistent with the course of the large carrier.

4. The autonomous return method according to claim 3, wherein in step S4, during the process of the autonomous underwater vehicle maintaining its course, it periodically engages in underwater acoustic communication with the large carrier to calculate the horizontal slant range D and bearing Br of the autonomous underwater vehicle relative to the large carrier, wherein when the horizontal slant range is less than or equal to 150 meters, the forward-view imaging sonar is activated to detect the distance R and bearing P of the large carrier relative to the autonomous underwater vehicle, and the course of the autonomous underwater vehicle is adjusted according to the current bearing P, when... At that time, the bow-stern line of the autonomous underwater vehicle coincides with the bow-stern line of the large carrier.

5. The autonomous return method according to claim 4, wherein in step S5, during the process of the autonomous underwater vehicle maintaining its course, when the forward-view imaging sonar detects that the horizontal slant distance D is less than or equal to 2 meters, the optical imaging system is activated to detect the hatch of the large carrier and obtain the hatch center point X and Y.

6. An autonomous underwater vehicle autonomous return system, characterized in that, include: The depth control module is used to output action commands based on the depth data h output by the depth gauge of the autonomous underwater vehicle and the depth data h1 of the large carrier output by the underwater acoustic communication device, so that the autonomous underwater vehicle is at the same depth as the large carrier. The distance and bearing calculation module is used to calculate the horizontal slant distance D and bearing Br of the autonomous underwater vehicle relative to the large carrier based on the latitude and longitude data lat and lon output by the inertial navigation system of the autonomous underwater vehicle and the latitude and longitude data lat1 and lon1 output by the underwater acoustic communication device, and output action commands to make the autonomous underwater vehicle move closer to the large carrier. The heading adjustment module is used to output action commands based on the heading data yaw output by the inertial navigation system of the autonomous underwater vehicle and the heading data yaw1 output by the underwater acoustic communication device of the large carrier, so that the heading of the autonomous underwater vehicle is consistent with the heading of the large carrier, and the bow of the autonomous underwater vehicle is facing the hatch of the large carrier. It is also used to output action commands based on the distance R and bearing P of the center point of the large carrier output by the forward view image sonar of the autonomous underwater vehicle, so that the bow-stern line of the autonomous underwater vehicle coincides with the bow-stern line of the large carrier. The attitude fine-tuning module is used to output action commands to fine-tune the attitude of the autonomous underwater vehicle based on the center points X and Y of the hatch of the large carrier output by the optical imaging system of the autonomous underwater vehicle, so that the autonomous underwater vehicle can enter the interior of the large carrier through the hatch of the large carrier.

7. The autonomous return system according to claim 6, wherein when the autonomous underwater vehicle approaches the large carrier, the autonomous underwater vehicle is allowed to periodically conduct underwater acoustic communication with the large carrier, and the distance and bearing calculation module calculates the horizontal slant range D and bearing Br of the autonomous underwater vehicle relative to the large carrier based on the latitude and longitude data lat and lon output by the inertial navigation system of the autonomous underwater vehicle and the latitude and longitude data lat1 and lon1 of the large carrier output by the underwater acoustic communication device.

8. The autonomous return system according to claim 7, wherein when the horizontal slant distance D is less than or equal to 500 meters and the bearing Br is less than or equal to 15 degrees, the heading adjustment module begins to adjust the heading of the autonomous underwater vehicle, the autonomous underwater vehicle periodically engages in underwater acoustic communication with the large carrier to obtain the heading yaw1 of the large carrier, and slowly adjusts its own heading yaw, wherein the heading yaw and heading yaw1 satisfy... At that time, the course of the autonomous underwater vehicle is consistent with the course of the large carrier.

9. The autonomous return system according to claim 8, wherein during the course of the autonomous underwater vehicle (AUV) maintaining its course, it periodically engages in underwater acoustic communication with the large carrier to calculate the horizontal slant range D and bearing Br of the AUV relative to the large carrier, wherein when the horizontal slant range is less than or equal to 150 meters, the forward-view image sonar is activated to detect the distance R and bearing P of the large carrier relative to the AUV, and based on the current bearing P, the course adjustment module adjusts the course of the AUV. At that time, the bow-stern line of the autonomous underwater vehicle coincides with the bow-stern line of the large carrier.

10. The autonomous return system according to claim 9, wherein during the course of the autonomous underwater vehicle maintaining its course, when the forward-view imaging sonar detects a horizontal slant distance D less than or equal to 2 meters, the optical imaging system is activated to detect the hatch of the large carrier and obtain the hatch center points X and Y. Subsequently, the attitude fine-tuning module fine-tunes the attitude of the autonomous underwater vehicle based on the hatch center points X and Y, so that the autonomous underwater vehicle can enter the interior of the large carrier through the hatch.

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