Split AUV system and method of use thereof

Abstract

A split type AUV system, including an autonomous underwater robot system and a buoy system, the autonomous underwater robot system includes an electric control sealed cabin, a multi-beam imaging sonar module, a magnetic attraction fixer, a visual positioning module, an ultra-short baseline (USBL) transponder beacon, a single beam wave sonar module, a depth module, an underwater laser range finder, a battery sealed cabin and a driving unit; the buoy system includes an ultra-short baseline (USBL) beacon, a floating platform, a cable reel motor, a cable reel, a satellite positioning module, a buoy system electric control cabin, a side scan sonar, an Aruco two-dimensional code plate, a driving unit, a permanent magnet block and a battery cabin; the purpose of the present application is to provide a split type AUV underwater navigation positioning system, which assists in obtaining the accurate position of the underwater robot.

Description

Technical Field

[0001] This invention relates to underwater unmanned surface vessel (AUV) technology, and in particular to a split-type AUV system and its application method. Background Technology

[0002] High autonomy is key to the successful completion of various tasks by autonomous underwater robots. Underwater environments typically present challenges such as shielding from satellite positioning signals, limited communication, and the complexity of the seabed environment, making it difficult to pre-deploy landmarks. These factors impact the accuracy of underwater navigation and positioning in the complex and unknown underwater space. Furthermore, current underwater radio communication technologies suffer from limited transmission distances, low efficiency, and poor stability.

[0003] To address the aforementioned issues, existing autonomous underwater vehicles (AUVs) employ a buoy-towing method. This involves a wired connection between the main AUV and a surface buoy, which is equipped with satellite positioning sensors and wireless data sensors. While this method solves the problem of acquiring satellite positioning signals underwater and allows for the transmission of massive amounts of data via the surface buoy, it also presents several drawbacks:

[0004] 1. The autonomous underwater vehicle obtains satellite positioning signals through a wired surface buoy. The location of the buoy is not the location of the autonomous underwater vehicle itself.

[0005] 2. Autonomous underwater robots cannot obtain their relative position to the buoy.

[0006] 3. When operating, autonomous underwater robots may overlook the obstacle avoidance issue of the connecting cables between themselves and the buoys.

[0007] These issues significantly reduce the high degree of autonomy of autonomous underwater vehicles (AUVs). Furthermore, if there are obstacles between the AUV and the buoy it is connected to, the connection line can be obstructed, thus affecting the AUV's operations. Summary of the Invention

[0008] To address the aforementioned shortcomings, the present invention aims to propose a detachable AUV underwater system to solve the problems described above.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] A split-type AUV system includes an autonomous underwater robot system and a buoy system. The autonomous underwater robot system includes an electrically controlled sealed cabin, a multi-beam imaging sonar module, a magnetic anchor, a visual positioning module, an ultra-short baseline USBL transponder beacon, a single-beam sonar module, a depth module, an underwater laser rangefinder, a battery sealed cabin, and a robot drive unit.

[0011] The electrically controlled sealed cabin is fixedly mounted with frames on its top, bottom, and sides. A multi-beam imaging sonar module is mounted on the lower part of the frame, and a visual positioning module is fixedly mounted at the center of the top surface of the frame. Multiple magnetic anchors are fixedly arranged on the top surface of the frame, and the magnetic anchors are arranged around the visual positioning module. An ultra-short baseline (USBL) transponder beacon is mounted on the top surface of the frame. Single-beam sonar modules facing forward are located on both sides of the frame, and single-beam sonar modules facing left and right are located on both sides of the frame. A depth module is mounted on the frame at the rear of the electrically controlled sealed cabin, and an underwater laser rangefinder is mounted on the inner side of the frame, with the illumination direction of the underwater laser rangefinder facing directly downwards. The battery sealed cabin and the robot drive unit are mounted on the frame.

[0012] The buoy system includes an ultra-short baseline (USBL) beacon, a floating platform, a cable reel motor, a cable reel, a satellite positioning module, a buoy system electrical control cabin, a side-scan sonar, an Aruco QR code board, a platform drive unit, a permanent magnet block, and a battery compartment.

[0013] The middle part of the floating platform is the load-bearing part, and buoyancy tanks are set on both sides of the load-bearing part. The buoy system electrical control cabin is installed on the load-bearing part of the floating platform, and a satellite positioning module is installed on the top of the buoy system electrical control cabin.

[0014] The cable reel is installed on the support unit, and the cable reel is equipped with a cable reel motor. The cable reel is mounted on the top of the buoy system's electrical control cabin via a bracket, and the cable reel contains a meter counter.

[0015] A side-scan sonar is installed on the bottom surface of the front part of the carrier, a battery compartment is installed at the rear of the carrier, a platform drive unit is installed on the bottom surface of the rear of the carrier, and an Aruco QR code board is provided at the center of the bottom surface of the carrier.

[0016] The buoyancy tank has a permanent magnet block on its downward-facing side.

[0017] Preferably, the interior of the electrically controlled sealed chamber includes a controller, a SINS module, a temperature and humidity sensor, a power line carrier communication module, a camera module, and a wired image transmission module;

[0018] The controller is connected to the power line carrier communication module, and the controller is also connected to the wired image transmission module.

[0019] The controller inside the electrically controlled sealed cabin collects information from the camera and transmits it to the buoy system via a wired image transmission module. The buoy system then establishes a connection with the ground station via a 5G network communication module to transmit images.

[0020] Preferably, the internal components of the buoy system's electrical control compartment include a controller, a SINS module, a power line carrier communication module, a wired image transmission module, and a 5G network communication module.

[0021] The controller is connected to the power line carrier communication module and the wired image transmission module.

[0022] Preferably, the four sets of magnetic anchors and four permanent magnets together constitute the connection structure between the autonomous underwater robot system and the buoy system;

[0023] The magnetic fastener is an electromagnetic structure.

[0024] Preferably, the wired image transmission module and the power line carrier communication module in the buoy system's electrical control compartment are connected to the wired image transmission module and the power line carrier communication module in the electrical control sealed compartment via cables.

[0025] On the other hand, an underwater positioning method is proposed for use in a split-type AUV system; the details are as follows:

[0026] By measuring the distance R between each acoustic element of the USLT beacon and the USLT transponder beacon, and simultaneously recording the phase difference of the acoustic pulse arriving at the transponder, the azimuth angle θ between the transponder and each acoustic element of the transducer can be determined. The coordinate position of the transponder in the buoy system coordinate system can be obtained by using the intersection method.

[0027] The origin O of the buoy system coordinates is located at the Ultra-Short Baseline (USBL) beacon, O' is the USBL transponder beacon, the X and Y axes are in the horizontal plane, with the X axis pointing forward of the buoy system, the Y axis perpendicular to the X axis pointing to the left of the buoy system, and the Z axis pointing vertically downward.

[0028] The geographical location of the buoy system is determined by the satellite positioning module. By accurately measuring the offset of the satellite positioning module from the coordinate origin O, the absolute geographical location of the USMR transponder beacon can be obtained. Then, by measuring the offset of the USMR transponder beacon from the autonomous underwater vehicle system, the absolute geographical location of the autonomous underwater vehicle system can be obtained.

[0029] Obtain the absolute geographical location of the buoy system of the autonomous underwater robot system;

[0030] After determining the distance R between the autonomous underwater robot system and the buoy system, the cable length can be changed by controlling the cable reel motor. The cable length L = R + Δ, where Δ is a given margin.

[0031] Furthermore, given the world coordinate system W, the autonomous underwater vehicle system coordinate system A, and the buoy system coordinate system B, the coordinate transformation of the buoy system's coordinates in the world coordinate system is as follows:

[0032]

[0033] Where, x W y W , zW x represents the coordinates of a point in the world coordinate system. B y B , z B T represents the point coordinates of the buoy system. BW Let R be the homogeneous transformation matrix of the buoy system in the world coordinate system, where R is the buoy system in the world coordinate system. BW P is an element of a 3x3 rotation matrix; BW The elements are 3x1 translation vectors; similarly, the coordinate transformation of the autonomous underwater robot system coordinates in the buoy system coordinate system is:

[0034]

[0035] Where, x A y A , z A T represents the point coordinates of an autonomous underwater robot system. AB This is the homogeneous transformation matrix of the autonomous underwater robot system in the buoy system coordinate system;

[0036] Among them, R AB P is an element of a 3x3 rotation matrix; AB The elements of a 3x1 translation vector;

[0037] The coordinate transformation of the autonomous underwater robot system in the world coordinate system is as follows:

[0038]

[0039] This allows us to obtain the relative positions of the autonomous underwater robot system and the buoy system.

[0040] Thirdly, an underwater docking method is proposed for a split-type AUV system, comprising the following steps:

[0041] Step 1: Using the USMR (Ultra-Short Baseline) beacon and the USMR transponder beacon, obtain the position coordinates of the autonomous underwater robot system relative to the buoy system;

[0042] Step 2: Bring the autonomous underwater robot system close to the buoy system, and align the Ax axis of the autonomous underwater robot system coordinate system with the Bx axis of the buoy system coordinate system.

[0043] Step 3: When the visual positioning module in the autonomous underwater robot system detects the Aruco QR code board of the buoy system 2, the attitude of the autonomous underwater robot system, including yaw angle, roll angle and pitch angle, is corrected to keep it in the same direction as the buoy system, and the use of the ultra-short baseline USBL beacon and the ultra-short baseline USBL transponder beacon is stopped.

[0044] Step 4: Use the PNP algorithm to solve for the coordinate system O of the Aruco QR code board.a -X a Y a Z a to the camera coordinate system O c -X c Y c Z c The rotation matrix and translation matrix to obtain the position coordinates of the autonomous underwater vehicle system relative to the buoy system, and then control the position of the autonomous underwater vehicle system to be directly below the buoy system, so that the Zc axis of the camera coordinate system coincides with the Za axis of the Aruco QR code; the Yc axis of the camera coordinate system is parallel to the Ya axis of the Aruco QR code; the ranging module in the visual positioning module measures the distance d between the visual positioning module and the Aruco QR code board;

[0045] Step Five, when the distance d between the visual positioning module and the Aruco QR code board is less than 10 cm, turn on the magnetic positioning device in the autonomous robot system, and continue to control the autonomous robot to approach the buoy system;

[0046] Step Six, finally complete the docking.

[0047] In the fourth aspect, a following and cable obstacle avoidance method is proposed. This underwater positioning method includes the following steps;

[0048] The autonomous underwater vehicle system and the buoy system achieve two-way follow-up through cooperative control: they keep sailing in the same direction and at the same speed, and control the cable reel motor to keep the cable at a length of L = R + Δ and in a non-tight state;

[0049] When the side-scan sonar of the buoy system detects an obstacle within the detection distance Rb, and the multi-beam imaging sonar module of the autonomous underwater vehicle system synchronously detects a feasible channel above and below the obstacle, the system will start a cooperative obstacle avoidance strategy; through dynamic control, the autonomous underwater vehicle system is kept at a safe threshold distance of R' < Rb from the obstacle, and at the same time, according to the multi-sensor fusion data, the upper channels A and B are selected for three-dimensional path planning, and the cable length is adjusted in real time to avoid the risk of the cable being entangled with the obstacle.

[0050] One of the above technical solutions includes the following beneficial effects: the autonomous underwater vehicle (AUV) system in the solution is equipped with a magnetic anchor, a visual positioning module, and an ultra-short baseline (USBL) transponder beacon; the buoy system is equipped with a permanent magnet, an USBL beacon, and an Aruco QR code board. These devices constitute the main docking structure between the AUV system and the buoy system. Position calculation is performed using the USBL transponder beacon and the USBL beacon, thereby obtaining the position of the AUV system based on the satellite positioning of the buoy system, and using this as a basis for mutual position adjustment between the AUV system and the buoy system. When docking is required, the AUV system scans the Aruco QR code board through the visual positioning module, thereby adjusting the attitude of the AUV system to facilitate subsequent magnetic attraction using the permanent magnet and the magnetic anchor. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the combined state of an autonomous underwater robot and a buoy system according to an embodiment of the present invention;

[0052] Figure 2 This is one of the overall structural schematic diagrams of an autonomous underwater robot and buoy system according to an embodiment of the present invention;

[0053] Figure 3 This is a second schematic diagram of the overall structure of an autonomous underwater robot and buoy system according to an embodiment of the present invention;

[0054] Figure 4 This is the third schematic diagram of the overall structure of an autonomous underwater robot and buoy system according to an embodiment of the present invention;

[0055] Figure 5 This is a schematic diagram showing the internal structure and connection relationship of the electrically controlled sealed chamber and the electrically controlled chamber of the buoy system of the present invention;

[0056] Figure 6 This is a schematic diagram of the underwater operation of an autonomous underwater robot and buoy system according to an embodiment of the present invention;

[0057] Figure 7 This is a schematic diagram of the Aruco QR code board according to an embodiment of the present invention, viewed from below.

[0058] Figure 8 This is a schematic diagram of the overall process of an underwater docking method according to an embodiment of the present invention;

[0059] Figure 9 This is a schematic diagram of an obstacle avoidance method according to an embodiment of the present invention;

[0060] Figure 10This is a schematic diagram of an autonomous underwater robot system and a buoy system from disassembly to assembly, according to an embodiment of the present invention.

[0061] Among them: Autonomous underwater robot system 1, electrically controlled sealed cabin 101, multi-beam imaging sonar module 102, magnetic fixation device 103, visual positioning module 104, ultra-short baseline USBL transponder beacon 105, single-beam sonar module 106, depth module 107, underwater laser rangefinder 108, battery sealed cabin 109, robot drive unit 110;

[0062] Buoy system 2, Ultra-short baseline USBL beacon 201, Buoyancy tank 202, Cable reel motor 203, Cable reel 204, Satellite positioning module 205, Buoy system electrical control compartment 206, Side scan sonar 207, Aruco QR code board 208, Platform drive unit 209, Permanent magnet block 210, Battery compartment 211. Detailed Implementation

[0063] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0064] like Figure 1-4 As shown, a split-type AUV system includes an autonomous underwater robot system 1 and a buoy system 2. The autonomous underwater robot system 1 includes an electronically controlled sealed cabin 101, a multi-beam imaging sonar module 102, a magnetic fixation device 103, a visual positioning module 104, an ultra-short baseline USBL transponder beacon 105, a single-beam sonar module 106, a depth module 107, an underwater laser rangefinder 108, a battery sealed cabin 109, and a robot drive unit 110.

[0065] The electrically controlled sealed cabin 101 has frames fixedly installed on its top, bottom, and sides. A multi-beam imaging sonar module 102 is installed on the lower part of the frame. A visual positioning module 104 is fixedly installed at the center of the top surface of the frame. Multiple magnetic retainers 103 are fixedly arranged on the top surface of the frame, and the multiple magnetic retainers 103 are arranged around the visual positioning module 104. An ultra-short baseline USBL transponder beacon 105 is installed on the top surface of the frame. Single-beam sonar modules 106 facing forward are respectively provided on both sides of the frame, and single-beam sonar modules 106 facing left and right are respectively provided on both sides of the frame. A depth module 107 is installed on the frame at the tail of the electrically controlled sealed cabin 101. An underwater laser rangefinder 108 is installed on the inner side of the frame, and the illumination direction of the underwater laser rangefinder 108 is directly downward. A battery sealed cabin 109 and a robot drive unit 110 are installed on the frame.

[0066] The buoy system 2 includes an ultra-short baseline USBL beacon 201, a floating platform, a cable reel motor 203, a cable reel 204, a satellite positioning module 205, a buoy system electrical control cabin 206, a side-scan sonar 207, an Aruco QR code board 208, a platform drive unit 209, a permanent magnet 210, and a battery compartment 211.

[0067] The middle part of the floating platform is the bearing part, and buoyancy tanks 202 are respectively provided on both sides of the bearing part. The buoy system electrical control cabin 206 is installed on the bearing part of the floating platform, and a satellite positioning module 205 is installed on the top of the buoy system electrical control cabin 206.

[0068] The cable reel 204 is installed on the support unit, and the cable reel 204 is equipped with a cable reel motor 203. The cable reel 204 is mounted on the top of the buoy system electrical control cabin 206 via a bracket.

[0069] A side-scan sonar 207 is installed on the bottom surface of the front part of the carrier, a battery compartment 211 is installed at the rear of the carrier, a platform drive unit 209 is installed on the bottom surface of the rear of the carrier, and an Aruco QR code board 208 is provided at the center of the bottom surface of the carrier.

[0070] The buoyancy tank 202 has a permanent magnet block 210 on its downward-facing surface.

[0071] The autonomous underwater vehicle (AUV) system 1 in this design includes a magnetic anchor 103, a visual positioning module 104, and an ultra-short baseline (USBL) transponder beacon 105. The buoy system 2 includes a permanent magnet 210, an USBL beacon 201, and an Aruco QR code board 208. These components form the main docking structure between AUV1 and buoy2. Position calculations are performed using the USBL transponder beacon 105 and USBL beacon 201, allowing AUV1 and buoy2 to adjust their positions accordingly. When docking is required, AUV1 scans the Aruco QR code board 208 using the visual positioning module 104, adjusting its attitude to facilitate subsequent magnetic attraction between the permanent magnet 210 and the magnetic anchor 103. The cable reel 204 contains a meter counter to measure the length of the extended cable, working in conjunction with the cable reel motor 203 to precisely control the length of the extended cable.

[0072] like Figure 5 As shown, the interior of the electrically controlled sealed chamber includes a controller, a SINS module, a temperature and humidity sensor, a power line carrier communication module, a camera module, and a wired image transmission module.

[0073] The controller is connected to the power line carrier communication module, and the controller is also connected to the wired image transmission module.

[0074] The controller inside the electrically controlled sealed cabin collects information from the camera and transmits it to the buoy system via a wired image transmission module. The buoy system then establishes a connection with the ground station via a 5G network communication module to transmit images.

[0075] The temperature and humidity sensor is used to measure whether water has entered the electrical control compartment. The depth module 107 is placed in the rear interface of the electrical control sealed compartment 101. The camera, wired image transmission module, and power line carrier communication module in the electrical control sealed compartment 101 are all connected to the controller of the electrical control sealed compartment 101. The SINS module is used for attitude monitoring and feedback.

[0076] like Figure 5 As shown, the internal components of the buoy system electrical control cabin 206 include a controller, a SINS module, a power line carrier communication module, a wired image transmission module, and a 5G network communication module.

[0077] The controller is connected to the power line carrier communication module and the wired image transmission module.

[0078] The SINS module is used for attitude monitoring and feedback. The wired image transmission module and power line carrier communication module in the buoy system's electrical control compartment 206 are both connected to the controller in the buoy system's electrical control compartment 206.

[0079] like Figure 2 As shown, four sets of magnetic retainers 103 and four permanent magnets 210 together constitute the connection structure between the autonomous underwater robot system 1 and the buoy system 2.

[0080] The magnetic fastener 103 is an electromagnetic structure.

[0081] The magnetic fastener 103 is an electromagnetic structure, and its magnetic attraction can be controlled electronically. This allows control over the combined and separated states of the autonomous underwater robot system 1 and the buoy system 2.

[0082] like Figure 5 As shown, the wired image transmission module and the power line carrier communication module in the buoy system's electrical control compartment 206 are connected to the wired image transmission module and the power line carrier communication module in the electrical control sealed compartment 101 via cables.

[0083] like Figure 6 As shown, an underwater positioning method is used in the split-type AUV system described in claim 5; specifically as follows:

[0084] By measuring the distance R between each acoustic element of the USLT beacon 201 and USLT transponder beacon 105, and simultaneously recording the phase difference of the acoustic pulse arriving at the transponder, the azimuth angle θ between the transponder and each acoustic element of the transducer can be determined. The coordinate position of the transponder in the buoy system 2 coordinate system can be obtained by using the intersection method.

[0085] The origin O of the buoy system 2 coordinate system is located at the ultra-short baseline USBL beacon 201, O' is the ultra-short baseline USBL transponder beacon 105, the X-axis and Y-axis are in the horizontal plane, with the X-axis pointing in front of the buoy system 2, the Y-axis perpendicular to the X-axis pointing to the left of the buoy system 2, and the Z-axis pointing vertically downwards.

[0086] The geographical location of the buoy system 2 is determined by the satellite positioning module 205. By accurately measuring the offset of the satellite positioning module 205 from the coordinate origin O, the absolute geographical location of the ultra-short baseline USBL transponder beacon 105 can be obtained. Then, by measuring the offset of the ultra-short baseline USBL transponder beacon 105 from the autonomous underwater robot system 1, the absolute geographical location of the autonomous underwater robot system 1 can be obtained.

[0087] Obtain the absolute geographical location of the buoy system 2 of the autonomous underwater robot system 1;

[0088] After determining the distance R between the autonomous underwater robot system 1 and the buoy system 2, the cable length can be changed by controlling the cable reel motor 203. The cable length L = R + Δ, where Δ is a given margin.

[0089] This technical solution combines ultra-short baseline (USBL) acoustic positioning with satellite positioning modules to achieve high-precision positioning and dynamic control of autonomous underwater vehicles (AUVs). Its core advantages lie in: USBL, through dual measurements of acoustic distance and phase difference, can quickly determine the three-dimensional coordinates of the AUV relative to the buoy system in complex underwater environments; by determining the positions of the USBL beacon 201 and the USBL transponder beacon, the required cable length L can be roughly determined; and a dynamic cable length adjustment mechanism (formula L = R + Δ) ensures the reliability of the physical connection between the autonomous underwater vehicle and the buoy system, while the margin Δ buffers the impact of water flow disturbances, ensuring stable operation of the system in complex sea conditions.

[0090] Wherein, the world coordinate system W, the coordinate system A of autonomous underwater robot system 1, and the coordinate system B of buoy system 2 are defined; then the coordinate transformation of buoy system 2 in the world coordinate system is:

[0091]

[0092] Where, x W y W , z W x represents the coordinates of a point in the world coordinate system. B y B , z B T represents the coordinates of a point in buoy system 2; BW Let R be the homogeneous transformation matrix of buoy system 2 in the world coordinate system, where R is the homogeneous transformation matrix of buoy system 2 in the world coordinate system.BW P is an element of a 3x3 rotation matrix; BW The elements are the translation vectors of 3x1; similarly, the coordinate transformation of the autonomous underwater robot system 1 coordinates in the buoy system 2 coordinate system is:

[0093]

[0094] Where, x A y A ,z A T represents the point coordinates of the autonomous underwater robot system 1; AB Let be the homogeneous transformation matrix of autonomous underwater robot system 1 in the coordinate system of buoy system 2;

[0095] Among them, R AB P is an element of a 3x3 rotation matrix; AB The elements of a 3x1 translation vector;

[0096] The coordinate transformation of Autonomous Underwater Robot System 1 in the world coordinate system is as follows:

[0097]

[0098] This allows the relative positions of the autonomous underwater robot system 1 and the buoy system 2 to be obtained.

[0099] To obtain the exact location of the underwater robot, the buoy system's position is determined by its satellite positioning module, and the underwater robot's position is obtained through the USBL module. By transforming the coordinates, the location of the autonomous underwater robot can be obtained. However, the buoy system is easily affected by natural factors on the water surface, causing inaccurate buoy positioning. The above solution updates the relative positions of the buoy system 2 and the autonomous underwater robot 1 in real time to ensure the accuracy of their position information.

[0100] like Figure 7 , Figure 8 and Figure 10 As shown, an underwater docking method is used in the split-type AUV system of claim 5; the method includes the following steps:

[0101] Step 1: Using the USMR USBL beacon 201 and USMR USBL transponder beacon 105, obtain the position coordinates of the autonomous underwater robot system 1 relative to the buoy system 2;

[0102] Step 2: Make the autonomous underwater robot system 1 approach the buoy system 2, and make the Ax axis of the coordinate system of the autonomous underwater robot system 1 and the Bx axis of the coordinate system of the buoy system 2 be in the same direction;

[0103] Step 3: When the visual positioning module in the autonomous underwater robot system 1 detects the Aruco QR code board 208 of the buoy system 2, the attitude of the autonomous underwater robot system 1 is corrected, including yaw angle, roll angle and pitch angle, so that it keeps in the same direction as the buoy system 2, and the use of the ultra-short baseline USBL beacon 201 and ultra-short baseline USBL transponder beacon 105 is stopped.

[0104] Step 4: Use the PNP algorithm to solve for the 208 coordinate system O of the Aruco QR code board. a -X a Y a Z a To camera coordinate system O c -X c Y c Z c The rotation and translation matrices are used to obtain the position coordinates of the autonomous underwater robot system 1 relative to the buoy system 2, and to control the position of the autonomous underwater robot system 1 to be kept directly below the buoy system 2, so that the Zc axis of the camera coordinate system coincides with the Za axis of the Aruco QR code; the Yc axis of the camera coordinate system is parallel to the Ya axis of the Aruco QR code; the ranging module in the visual positioning module measures the distance d between the visual positioning module and the Aruco QR code board.

[0105] Step 5: When the distance d between the visual positioning module and the Aruco QR code board is less than 10cm, activate the magnetic locator in the autonomous robot system and continue to control the autonomous robot to approach the buoy system.

[0106] Step six, finally complete the docking.

[0107] At long distances, the visibility of the vision module is very low. Therefore, an ultra-short baseline (UBS) USBL beacon 201 and an UBS USBL transponder beacon 105 are used to obtain the position coordinates of the autonomous underwater vehicle (AUV) system 1 relative to the buoy system 2, enabling rapid control of AUV 1 to approach the buoy system 2. At close distances, the accuracy error of the UBS USBL beacon positioning module increases, making it unsuitable for precise positioning control. Instead, a camera is used to scan the Aruco QR code board, and the SINS module is used to adjust the attitude, while the ranging module measures the distance d between the vision positioning module and the Aruco QR code board to complete the precise docking task. This approach leverages the advantages of both the UBS USBL beacon and the vision positioning module while compensating for their respective disadvantages.

[0108] like Figure 9 As shown, a following and cable obstacle avoidance method is used in the underwater positioning method of claim 6, comprising the following steps;

[0109] The autonomous underwater vehicle system 1 and the buoy system 2 achieve two-way follow-up through collaborative control: they maintain the same direction and speed of navigation, and control the cable reel motor to keep the cable at a length of L = R + Δ and in a non-tight state;

[0110] When the side-scan sonar 207 of the buoy system 2 detects an obstacle within the detection distance Rb, and the multi-beam imaging sonar module 102 of the autonomous underwater vehicle system 1 synchronously detects a feasible passage above and below the obstacle, the system will initiate a collaborative obstacle avoidance strategy; by dynamically controlling, the autonomous underwater vehicle system 1 is kept at a safe threshold distance of R' < Rb from the obstacle, and at the same time, the upper channels A and B are selected for three-dimensional path planning based on the multi-sensor fusion data, and the cable length is adjusted in real time to avoid the risk of the cable being entangled with the obstacle.

[0111] This two-way follow-up mechanism can not only achieve the follow-up of the autonomous underwater vehicle system 1 to the buoy system 2, but also achieve the follow-up of the buoy system 2 to the autonomous underwater vehicle system 1. Its core advantage is that it effectively avoids the position drift of the cable caused by water flow disturbance, and always maintains the controllable state of the cable spatial configuration through active cable length regulation, greatly improving the autonomy and freedom of the equipment.

[0112] The technical principle of the present invention has been described above in combination with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be construed as any limitation to the protection scope of the present invention. Based on the explanations herein, those skilled in the art can readily conceive of other specific embodiments of the present invention without creative efforts, and these embodiments will fall within the protection scope of the present invention.

Claims

1. A split-type AUV system, comprising an autonomous underwater robot system and a buoy system, characterized in that, The autonomous underwater robot system includes an electrically controlled sealed cabin, a multi-beam imaging sonar module, a magnetic fixation device, a visual positioning module, an ultra-short baseline USBL transponder beacon, a single-beam sonar module, a depth module, an underwater laser rangefinder, a battery sealed cabin, and a robot drive unit. The electrically controlled sealed cabin is fixedly mounted with frames on its top, bottom, and sides. A multi-beam imaging sonar module is mounted on the lower part of the frame, and a visual positioning module is fixedly mounted at the center of the top surface of the frame. Multiple magnetic anchors are fixedly arranged on the top surface of the frame, and the magnetic anchors are arranged around the visual positioning module. An ultra-short baseline (USBL) transponder beacon is mounted on the top surface of the frame. Single-beam sonar modules facing forward are located on both sides of the frame, and single-beam sonar modules facing left and right are located on both sides of the frame. A depth module is mounted on the frame at the rear of the electrically controlled sealed cabin, and an underwater laser rangefinder is mounted on the inner side of the frame, with the illumination direction of the underwater laser rangefinder facing directly downwards. The battery sealed cabin and the robot drive unit are mounted on the frame. The buoy system includes an ultra-short baseline (USBL) beacon, a floating platform, a cable reel motor, a cable reel, a satellite positioning module, a buoy system electrical control cabin, a side-scan sonar, an Aruco QR code board, a platform drive unit, a permanent magnet block, and a battery compartment. The middle part of the floating platform is the load-bearing part, and buoyancy tanks are set on both sides of the load-bearing part. The buoy system electrical control cabin is installed on the load-bearing part of the floating platform, and a satellite positioning module is installed on the top of the buoy system electrical control cabin. The cable reel is installed on the support unit, and the cable reel is equipped with a cable reel motor. The cable reel is mounted on the top of the buoy system's electrical control cabin via a bracket, and the cable reel contains a meter counter. A side-scan sonar is installed on the bottom surface of the front part of the carrier, a battery compartment is installed at the rear of the carrier, a platform drive unit is installed on the bottom surface of the rear of the carrier, and an Aruco QR code board is provided at the center of the bottom surface of the carrier. The buoyancy tank has a permanent magnet block on its downward-facing side.

2. The split-type AUV system according to claim 1, characterized in that, The interior of the electrically controlled sealed chamber contains a controller, a SINS module, a temperature and humidity sensor, a power line carrier communication module, a camera module, and a wired image transmission module; The controller is connected to the power line carrier communication module, and the controller is also connected to the wired image transmission module. The controller inside the electrically controlled sealed cabin collects information from the camera and transmits it to the buoy system via a wired image transmission module. The buoy system then establishes a connection with the ground station via a 5G network communication module to transmit images.

3. The split-type AUV system according to claim 2, characterized in that, The internal components of the buoy system's electrical control cabin include a controller, a SINS module, a power line carrier communication module, a wired image transmission module, and a 5G network communication module. The controller is connected to the power line carrier communication module and the wired image transmission module.

4. The split-type AUV system according to claim 3, characterized in that, Four sets of magnetic anchors and four permanent magnets together constitute the connection structure between the autonomous underwater robot system and the buoy system. The magnetic fastener is an electromagnetic structure.

5. The split-type AUV system according to claim 4, characterized in that, The wired image transmission module and power line carrier communication module in the buoy system's electrical control cabin are connected to the wired image transmission module and power line carrier communication module in the sealed electrical control cabin via cables.

6. An underwater positioning method, characterized in that, This method is used in the split-type AUV system of claim 5; specifically as follows: By measuring the distance R between each acoustic element of the USLT beacon and the USLT transponder beacon, and simultaneously recording the phase difference of the acoustic pulse arriving at the transponder, the azimuth angle θ between the transponder and each acoustic element of the transducer can be determined. The coordinate position of the transponder in the buoy system coordinate system can be obtained by using the intersection method. The origin O of the buoy system coordinates is located at the Ultra-Short Baseline (USBL) beacon, O' is the USBL transponder beacon, the X and Y axes are in the horizontal plane, with the X axis pointing forward of the buoy system, the Y axis perpendicular to the X axis pointing to the left of the buoy system, and the Z axis pointing vertically downward. The geographical location of the buoy system is determined by the satellite positioning module. By accurately measuring the offset of the satellite positioning module from the coordinate origin O, the absolute geographical location of the USMR transponder beacon can be obtained. Then, by measuring the offset of the USMR transponder beacon from the autonomous underwater vehicle system, the absolute geographical location of the autonomous underwater vehicle system can be obtained. Obtain the absolute geographical location of the buoy system of the autonomous underwater robot system; After determining the distance R between the autonomous underwater robot system and the buoy system, the cable length can be changed by controlling the cable reel motor. The cable length L = R + Δ, where Δ is a given margin.

7. The underwater positioning method according to claim 6, characterized in that, Given a world coordinate system W, an autonomous underwater vehicle (AUV) system coordinate system A, and a buoy system coordinate system B, the coordinate transformation of the buoy system's coordinates in the world coordinate system is as follows: Where, x W y W , z W x represents the coordinates of a point in the world coordinate system. B y B , z B T represents the point coordinates of the buoy system. BW Let R be the homogeneous transformation matrix of the buoy system in the world coordinate system, where R is the buoy system in the world coordinate system. BW P is an element of a 3x3 rotation matrix; BW The elements are 3x1 translation vectors; similarly, the coordinate transformation of the autonomous underwater robot system coordinates in the buoy system coordinate system is: Where, x A y A , z A T represents the point coordinates of an autonomous underwater robot system. AB This is the homogeneous transformation matrix of the autonomous underwater robot system in the buoy system coordinate system; Among them, R AB P is an element of a 3x3 rotation matrix; AB The elements of a 3x1 translation vector; The coordinate transformation of the autonomous underwater robot system in the world coordinate system is as follows: This allows us to obtain the relative positions of the autonomous underwater robot system and the buoy system.

8. An underwater docking method, characterized in that, This method is used in the split-type AUV system of claim 5; it includes the following steps: Step 1: Using the USMR (Ultra-Short Baseline) beacon and the USMR transponder beacon, obtain the position coordinates of the autonomous underwater robot system relative to the buoy system; Step 2: Bring the autonomous underwater robot system close to the buoy system, and align the Ax axis of the autonomous underwater robot system coordinate system with the Bx axis of the buoy system coordinate system. Step 3: When the vision positioning module in the autonomous underwater vehicle system detects the Aruco QR code board of the buoy system, the attitude of the autonomous underwater vehicle system, including yaw angle, roll angle and pitch angle, is corrected to keep it in the same direction as the buoy system, and the use of the UBS USBL beacon and UBS USBL transponder beacon is stopped. Step 4: Use the PNP algorithm to solve for the coordinate system O of the Aruco QR code board. a -X a Y a Z a To camera coordinate system O c -X c Y c Z c The rotation and translation matrices are used to obtain the position coordinates of the autonomous underwater robot system relative to the buoy system, and to control the position of the autonomous underwater robot system to be kept directly below the buoy system, so that the Zc axis of the camera coordinate system coincides with the Za axis of the Aruco QR code; the Yc axis of the camera coordinate system is parallel to the Ya axis of the Aruco QR code; the ranging module in the visual positioning module measures the distance d between the visual positioning module and the Aruco QR code board. Step 5: When the distance d between the visual positioning module and the Aruco QR code board is less than 10cm, activate the magnetic locator in the autonomous robot system and continue to control the autonomous robot to approach the buoy system. Step six, finally complete the docking.

9. A following and cable obstacle avoidance method, characterized in that, This method, used in the underwater positioning method of claim 6, includes the following steps; The autonomous underwater robot system and the buoy system achieve bidirectional homing through coordinated control: both maintain the same direction and speed, and the cable reel motor is controlled to keep the cable at a length of L = R + Δ and in a non-taut state; When the side-scan sonar of the buoy system detects an obstacle within the detection range Rb, and the multi-beam imaging sonar module of the autonomous underwater vehicle system synchronously detects feasible channels above and below the obstacle, the system will initiate a cooperative obstacle avoidance strategy; by dynamically controlling, the autonomous underwater vehicle system is kept at a safe threshold distance R' < Rb from the obstacle, and at the same time, according to the multi-sensor fusion data, channels A and B above are selected for three-dimensional path planning, and the cable length is adjusted in real time to avoid the risk of the cable being entangled with the obstacle.

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