Split type AUV (Autonomous Underwater Vehicle) system and application method thereof

Abstract

A split type AUV system comprises an autonomous underwater robot system and a buoy system, the autonomous underwater robot system comprises an electric control sealed cabin, a multi-beam imaging sonar module, a magnetic attraction fixing device, a visual positioning module, an ultra-short baseline USBL transponder beacon, a single-beam sonar module, a depth module, an underwater laser range finder, a battery sealed cabin and a driving unit; the buoy system comprises an ultra-short base line 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 invention aims to provide an underwater navigation positioning system of a split type AUV (Autonomous Underwater Vehicle), which assists in acquiring the accurate position of an underwater robot.

Description

Technical Field

[0001] The present invention relates to underwater unmanned vehicle technology, and in particular to a split AUV system and an application method thereof. Background Art

[0002] A high degree of autonomy is crucial for autonomous underwater robots to successfully complete various missions. Underwater environments often experience shielding from satellite positioning signals, limited communications, a complex seabed environment, and the difficulty of pre-deploying landmarks. This impacts the accuracy of underwater navigation and positioning in the complex and unknown seabed. Furthermore, existing underwater radio communication technologies suffer from limited transmission range, low efficiency, and poor stability.

[0003] To address these issues, existing autonomous underwater robots (AUVs) employ a buoy-towing approach. Specifically, the AUV is connected to a surface buoy via a wired connection. The buoy carries satellite positioning sensors and wireless data sensors. While this buoy-towing approach solves the AUV's problem of acquiring satellite positioning signals underwater and can transmit massive amounts of data via the surface buoy, it presents several challenges:

[0004] 1. The autonomous underwater robot obtains satellite positioning signals through a wired surface buoy. The signal is not the position of the autonomous underwater robot itself, but the position of the buoy to which it is connected.

[0005] 2. The autonomous underwater robot cannot obtain its relative position with the buoy.

[0006] 3. When operating, the autonomous underwater robot will ignore the problem of obstacle avoidance of the connecting cable between it and the buoy.

[0007] These problems greatly reduce the high degree of autonomy of the autonomous underwater robot. At the same time, if there is an obstacle between the autonomous underwater robot and the buoy to which it is connected, this will cause the connection line to be blocked, thereby affecting the operation of the autonomous underwater robot. Summary of the Invention

[0008] In view of the above-mentioned defects, the purpose of the present invention is to propose a detachable underwater AUV system to solve the above-mentioned problems.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] A split 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 fixer, 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] Frames are fixedly installed on the upper and lower sides and both sides of the electrically controlled sealed cabin, a multi-beam imaging sonar module is installed on the lower part of the frame, a visual positioning module is fixedly installed on the center of the top surface of the frame, and a plurality of magnetic holders are fixedly arranged on the top surface of the frame, and the plurality of magnetic holders are arranged around the visual positioning module; an ultra-short baseline USBL transponder beacon is installed on the top surface of the frame; single-beam sonar modules facing forward are respectively provided on both sides of the frame, and single-beam sonar modules facing left and right are respectively provided on both sides of the frame; a depth module is installed on the frame at the tail of the electrically controlled sealed cabin, an underwater laser rangefinder is installed on the inner side of the frame, and the irradiation direction of the underwater laser rangefinder is facing directly downward; a battery sealed cabin and a robot drive unit are installed on the frame;

[0012] The buoy system includes an ultra-short baseline USBL beacon, a floating platform, a cable drum motor, a cable reel, a satellite positioning module, a buoy system electric 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, with buoyancy barrels 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 bearing part, the cable reel is equipped with a cable reel motor, the cable reel is mounted above the electric control cabin of the buoy system through a bracket, and the cable reel includes a meter;

[0015] A side-scan sonar is installed on the bottom surface of the front of the carrying part, a battery compartment is installed on the rear of the carrying part, a platform drive unit is installed on the bottom surface of the rear of the carrying part, and an Aruco QR code plate is installed in the center of the bottom surface of the carrying part;

[0016] The downward surface of the buoyancy barrel is provided with a permanent magnet block.

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

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

[0019] The controller inside the electronically controlled sealed cabin collects camera information and transmits it to the buoy system through the wired image transmission module. The buoy system establishes contact with the ground station through the 5G network communication module to transmit images.

[0020] Preferably, the electric control cabin of the buoy system includes a controller, a SINS module, a power carrier communication module, a wired image transmission module and a 5G network communication module;

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

[0022] Preferably, four sets of magnetic fixators and four permanent magnet blocks together constitute a connection structure between the autonomous underwater robot system and the buoy system;

[0023] The magnetic holder is an electromagnetic structure.

[0024] Preferably, the wired image transmission module and the power carrier communication module in the electric control cabin of the buoy system are connected to the wired image transmission module and the power carrier communication module in the electric control sealed cabin through cables.

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

[0026] By measuring the distance R between the ultra-short baseline USBL beacon and each acoustic element of the ultra-short baseline USBL transponder beacon, and recording the phase difference of the sound pulse reaching the transponder, the azimuth angle θ between the transponder and each acoustic element of the transducer is determined, and 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 ultra-short baseline USBL transponder beacon, the X-axis and Y-axis are in the horizontal plane, and the X-axis points to the front of the buoy system, the Y-axis is perpendicular to the X-axis and points to the left of the buoy system, and the Z-axis is vertically downward;

[0028] The geographic location of the buoy system is determined by the satellite positioning module. By accurately measuring the offset from the satellite positioning module to the coordinate origin O, the absolute geographic location of the ultra-short baseline USBL transponder beacon can be obtained. Then, the offset from the ultra-short baseline USBL transponder beacon to the autonomous underwater robot system can be used to obtain the absolute geographic location of the autonomous underwater robot system.

[0029] Obtaining the absolute geographic location of the buoy system of the autonomous underwater vehicle 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 drum motor, and the cable length L = R + Δ, where Δ is a given margin.

[0031] Furthermore, the world coordinate system W, the autonomous underwater robot system coordinate system A, and the buoy system coordinate system B are determined; then the coordinate transformation of the buoy system coordinates in the world coordinate system is:

[0032]

[0033] Among them, x W ,y W , zW is the point coordinate in the world coordinate system; x B ,y B , z B is the point coordinate of the buoy system; T BW is the homogeneous transformation matrix of the buoy system in the world coordinate system, where R BW is the element of the 3x3 rotation matrix; P BW is the element of the 3x1 translation vector; similarly, the coordinate transformation of the autonomous underwater robot system in the buoy system coordinate system is:

[0034]

[0035] Among them, x A ,y A , z A is the point coordinate of the autonomous underwater robot system; T AB is the homogeneous transformation matrix of the autonomous underwater robot system in the buoy system coordinate system;

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

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

[0038]

[0039] Thereby obtaining the relative position of the autonomous underwater robot system and the buoy system.

[0040] In a third aspect, an underwater docking method is proposed, which is used for a split AUV system and includes the following steps:

[0041] Step 1: Using the ultra-short baseline USBL beacon and the ultra-short baseline USBL transponder beacon, the position coordinates of the autonomous underwater robot system relative to the buoy system are obtained;

[0042] Step 2: The autonomous underwater robot system is brought close to the buoy system, and the Ax axis of the autonomous underwater robot system coordinate system is in the same direction as 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 plate of the buoy system 2, the posture of the autonomous underwater robot system, including the 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 the Aruco QR code board coordinate system Oa -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, and then obtain the position coordinates of the autonomous underwater robot system relative to the buoy system, control the position of the autonomous underwater robot system to be directly below the buoy system, and make the Zc axis of the camera coordinate system coincide 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, activate 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] Fourthly, a following and cable obstacle avoidance method is proposed. This underwater positioning method includes the following steps;

[0048] The autonomous underwater robot system and the buoy system achieve two-way follow-up through collaborative 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 robot system synchronously detects that there are feasible channels above and below the obstacle, the system will activate the collaborative obstacle avoidance strategy; dynamically control the autonomous underwater robot system to keep a safe threshold distance of R' < Rb from the obstacle, and at the same time select the upper channels A and B for three-dimensional path planning according to the multi-sensor fusion data, and adjust the cable length 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 robot system in the solution is equipped with a magnetic fixture, a visual positioning module and an ultra-short baseline USBL transponder beacon, and the buoy system is equipped with a permanent magnet block, an ultra-short baseline USBL beacon and an Aruco QR code board. The above devices constitute the main docking structure of the autonomous underwater robot system and the buoy system. The position is calculated by the ultra-short baseline USBL transponder beacon and the ultra-short baseline USBL beacon, so that the position of the autonomous underwater robot system can be further obtained based on the satellite positioning of the buoy system, and the autonomous underwater robot system and the buoy system can be adjusted to each other based on this; when docking is required, the autonomous underwater robot system scans the Aruco QR code board through the visual positioning module, and then adjusts the posture of the autonomous underwater robot system, so as to facilitate the subsequent use of the permanent magnet block and the magnetic fixture for magnetic adsorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 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 diagrams of the autonomous underwater robot and buoy system according to one embodiment of the present invention;

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

[0055] Figure 5 It is a schematic diagram of the internal structure and connection relationship of the electric control cabin and the electric control cabin of the buoy system of the present invention;

[0056] Figure 6 1 is a schematic diagram of underwater operation of an autonomous underwater robot and a buoy system according to an embodiment of the present invention;

[0057] Figure 7 1. This is a schematic diagram of an Aruco QR code board as viewed from above according to an embodiment of the present invention;

[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 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 a disassembled to an assembled state according to an embodiment of the present invention.

[0061] Wherein: autonomous underwater robot system 1, electric control sealed cabin 101, multi-beam imaging sonar module 102, magnetic holder 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 barrel 202, cable drum motor 203, cable reel 204, satellite positioning module 205, buoy system electrical control cabin 206, side scan sonar 207, Aruco QR code board 208, platform drive unit 209, permanent magnet block 210, battery compartment 211. DETAILED DESCRIPTION

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

[0064] like Figure 1-4 As shown, a split AUV system includes an autonomous underwater robot system 1 and a buoy system 2. The autonomous underwater robot system 1 includes an electric control sealed cabin 101, a multi-beam imaging sonar module 102, a magnetic fixer 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] Frames are fixedly installed on the upper and lower sides and both sides of the electrically controlled sealed cabin 101, 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, and a plurality of magnetic holders 103 are fixedly arranged on the top surface of the frame, and a plurality of magnetic holders 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 irradiation direction of the underwater laser rangefinder 108 is facing 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 drum motor 203, a cable reel 204, a satellite positioning module 205, a buoy system electric control cabin 206, a side scan sonar 207, an Aruco QR code board 208, a platform drive unit 209, a permanent magnet block 210 and a battery compartment 211;

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

[0068] The cable reel 204 is mounted on the bearing portion. The cable reel motor 203 is installed on the cable reel 204. The cable reel 204 is mounted above the electric control cabin 206 of the buoy system through a bracket.

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

[0070] A permanent magnet 210 is provided on the downward surface of the buoyancy barrel 202 .

[0071] The AUV system 1 includes a magnetic fixture 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 ultra-short baseline USBL beacon 201, and an Aruco QR code plate 208. These devices form the primary docking structure between the AUV system 1 and the buoy system 2. The ultra-short baseline USBL transponder beacon 105 and the ultra-short baseline USBL beacon 201 calculate their positions, which are then used to adjust the positions of the AUV system 1 and the buoy system 2. When docking is necessary, the AUV system 1 scans the Aruco QR code plate 208 through the visual positioning module 104, adjusting the AUV system 1's posture and facilitating subsequent magnetic attraction between the permanent magnet 210 and the magnetic fixture 103. The cable reel 204 includes a meter to measure the length of the extended cable, which, in conjunction with the cable reel motor 203, allows for precise control of the extended cable length.

[0072] like Figure 5 As shown, the interior of the electronically controlled sealed cabin contains a controller, SINS module, temperature and humidity sensors, power carrier communication module, camera module and wired image transmission module;

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

[0074] The controller inside the electronically controlled sealed cabin collects camera information and transmits it to the buoy system through the wired image transmission module. The buoy system establishes contact with the ground station through the 5G network communication module to transmit images.

[0075] The temperature and humidity sensors are used to measure water ingress into the electronically controlled cabin. The depth module 107 is placed in the rear port of the electronically controlled sealed cabin 101. The camera, wired image transmission module, and power carrier communication module in the electronically controlled sealed cabin 101 are all connected to the controller of the electronically controlled sealed cabin 101. The SINS module is used for attitude monitoring and feedback.

[0076] like Figure 5 As shown, the buoy system electrical control cabin 206 includes a controller, a SINS module, a power carrier communication module, a wired image transmission module and a 5G network communication module;

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

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

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

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

[0081] The magnetic fixture 103 is an electromagnetic structure, and its magnetic properties can be controlled by electrical control, so as to control the combination and separation 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 carrier communication module in the electric control cabin 206 of the buoy system are connected to the wired image transmission module and the power carrier communication module in the electric control sealed cabin 101 through cables.

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

[0084] By measuring the distance R between each acoustic element of the ultra-short baseline USBL beacon 201 and the ultra-short baseline USBL transponder beacon 105, and recording the phase difference of the acoustic pulse reaching the transponder, the azimuth angle θ between the transponder and each acoustic element of the transducer is determined, and the coordinate position of the transponder in the coordinate system of the buoy system 2 can be obtained by using the intersection method;

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

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

[0087] Obtaining the absolute geographic 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 drum motor 203, where the cable length L = R + Δ, where Δ is a given margin.

[0089] This technical solution, by combining ultra-short baseline (USBL) acoustic positioning with satellite positioning modules, enables high-precision positioning and dynamic control of autonomous underwater vehicles (AUVs). Its core advantages are: USBL uses dual measurements of acoustic element distance and phase difference to quickly determine the three-dimensional coordinates of the AUV relative to the buoy system in complex underwater environments. By determining the positions of the ultra-short baseline USBL beacon 201 and the ultra-short baseline USBL transponder beacon, the required cable length L can be roughly determined. A dynamic cable length adjustment mechanism (formula L = R + Δ) is used to ensure the reliability of the physical connection between the AUV and the buoy system, while also buffering the effects of water flow disturbances by setting a margin Δ, ensuring the system's stable operation in complex sea conditions.

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

[0091]

[0092] Among them, x W ,y W , z W is the point coordinate in the world coordinate system; x B ,y B , z B is the point coordinate of buoy system 2; T BW is the homogeneous transformation matrix of buoy system 2 in the world coordinate system, where RBW is the element of the 3x3 rotation matrix; P BW is the element of the 3x1 translation vector; similarly, the coordinate transformation of the autonomous underwater robot system 1 in the buoy system 2 coordinate system is:

[0093]

[0094] Among them, x A ,y A ,z A is the point coordinate of the autonomous underwater robot system 1; T AB is the homogeneous transformation matrix of the autonomous underwater robot system 1 in the coordinate system of the buoy system 2;

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

[0096] The coordinate transformation of the autonomous underwater robot system 1 in the world coordinate system is:

[0097]

[0098] Thereby, the relative positions of the autonomous underwater robot system 1 and the buoy system 2 are obtained.

[0099] In order to obtain the specific position of the underwater robot, the position of the buoy system can only be determined through the satellite positioning module on the buoy system, and then the position of the underwater robot can be obtained through the USBL module. Through coordinate transformation, the position of the autonomous underwater robot can be obtained; the buoy system is easily affected by natural factors on the water surface and its position changes, resulting in inaccurate buoy positioning. The relative position of the buoy system 2 and the autonomous underwater robot 1 is updated in real time through the above scheme to ensure the accuracy of the position information of the buoy system 2 and the autonomous underwater robot 1.

[0100] like Figure 7 、 Figure 8 and Figure 10 As shown, an underwater docking method is used for the split AUV system according to claim 5; the method comprises the following steps:

[0101] Step 1: using the ultra-short baseline USBL beacon 201 and the ultra-short baseline USBL transponder beacon 105, obtaining the position coordinates of the autonomous underwater robot system 1 relative to the buoy system 2;

[0102] Step 2: The autonomous underwater robot system 1 is brought close to the buoy system 2, and the Ax axis of the coordinate system of the autonomous underwater robot system 1 is in the same direction as the Bx axis of the coordinate system of the buoy system 2;

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

[0104] Step 4: Use the PNP algorithm to solve the Aruco QR code board 208 coordinate system O 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 are used to obtain the position coordinates of the autonomous underwater robot system 1 relative to the buoy system 2, and the position of the autonomous underwater robot system 1 is controlled to remain 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 distance measurement 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 10 cm, the magnetic locator in the autonomous robot system is turned on, and the autonomous robot continues to be controlled to approach the buoy system;

[0106] Step six, finally complete the docking.

[0107] At long distances, the visual module's visibility is very low. Therefore, the ultra-short baseline USBL beacon 201 and ultra-short baseline USBL transponder beacon 105 are used to obtain the position coordinates of the autonomous underwater robot system 1 relative to the buoy system 2, allowing the autonomous underwater robot system 1 to quickly approach the buoy system 2. At close ranges, the ultra-short baseline USBL beacon's positioning module accuracy error increases, making it unsuitable for precise positioning control. Instead, a camera is used to scan the Aruco QR code plate, and the SINS module is used to adjust the attitude. The ranging module measures the distance d between the visual positioning module and the Aruco QR code plate, completing the precise docking task. This leverages the respective strengths of the ultra-short baseline USBL beacon and the visual positioning module, while compensating for their respective weaknesses.

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

[0109] The autonomous underwater vehicle system 1 and the buoy system 2 achieve two-way follow-up through cooperative 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 channel above and below the obstacle, the system will initiate a cooperative 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, based on 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.

[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联想到 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 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 fixer, 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; Frames are fixedly installed on the upper and lower sides and both sides of the electrically controlled sealed cabin, a multi-beam imaging sonar module is installed on the lower part of the frame, a visual positioning module is fixedly installed on the center of the top surface of the frame, and a plurality of magnetic holders are fixedly arranged on the top surface of the frame, and the plurality of magnetic holders are arranged around the visual positioning module; an ultra-short baseline USBL transponder beacon is installed on the top surface of the frame; single-beam sonar modules facing forward are respectively provided on both sides of the frame, and single-beam sonar modules facing left and right are respectively provided on both sides of the frame; a depth module is installed on the frame at the tail of the electrically controlled sealed cabin, an underwater laser rangefinder is installed on the inner side of the frame, and the irradiation direction of the underwater laser rangefinder is facing directly downward; a battery sealed cabin and a robot drive unit are installed on the frame; The buoy system includes an ultra-short baseline USBL beacon, a floating platform, a cable drum motor, a cable reel, a satellite positioning module, a buoy system electric 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, with buoyancy barrels 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 bearing part, the cable reel is equipped with a cable reel motor, the cable reel is mounted above the electric control cabin of the buoy system through a bracket, and the cable reel includes a meter; A side-scan sonar is installed on the bottom surface of the front of the carrying part, a battery compartment is installed on the rear of the carrying part, a platform drive unit is installed on the bottom surface of the rear of the carrying part, and an Aruco QR code plate is installed in the center of the bottom surface of the carrying part; The downward surface of the buoyancy barrel is provided with a permanent magnet block.

2. The split AUV system according to claim 1, characterized in that: The interior of the electronically controlled sealed cabin contains a controller, SINS module, temperature and humidity sensors, power carrier communication module, camera module and wired image transmission module; The controller is connected to the power carrier communication module, and the controller is connected to the wired image transmission module; The controller inside the electronically controlled sealed cabin collects camera information and transmits it to the buoy system through the wired image transmission module. The buoy system establishes contact with the ground station through the 5G network communication module to transmit images.

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

4. The split AUV system according to claim 3, characterized in that: Four sets of magnetic fixators and four permanent magnets together form the connection structure between the autonomous underwater robot system and the buoy system; The magnetic holder is an electromagnetic structure.

5. The split AUV system according to claim 4, characterized in that: The wired image transmission module and the power carrier communication module in the electric control cabin of the buoy system are connected to the wired image transmission module and the power carrier communication module in the electric control sealed cabin through cables.

6. An underwater positioning method, characterized in that: The method is used for the split AUV system described in claim 5; specifically, as follows: By measuring the distance R between the ultra-short baseline USBL beacon and each acoustic element of the ultra-short baseline USBL transponder beacon, and recording the phase difference of the sound pulse reaching the transponder, the azimuth angle θ between the transponder and each acoustic element of the transducer is determined, and 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 ultra-short baseline USBL transponder beacon, the X-axis and Y-axis are in the horizontal plane, and the X-axis points to the front of the buoy system, the Y-axis is perpendicular to the X-axis and points to the left of the buoy system, and the Z-axis is vertically downward; The geographic location of the buoy system is determined by the satellite positioning module. By accurately measuring the offset from the satellite positioning module to the coordinate origin O, the absolute geographic location of the ultra-short baseline USBL transponder beacon can be obtained. Then, the offset from the ultra-short baseline USBL transponder beacon to the autonomous underwater robot system can be used to obtain the absolute geographic location of the autonomous underwater robot system. Obtaining the absolute geographic location of the buoy system of the autonomous underwater vehicle 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 drum motor, and the cable length L = R + Δ, where Δ is a given margin.

7. The underwater positioning method according to claim 6, characterized in that: Determine the world coordinate system W, the autonomous underwater robot system coordinate system A, and the buoy system coordinate system B; then the coordinate transformation of the buoy system in the world coordinate system is: Among them, x W ,y W , z W is the point coordinate in the world coordinate system; x B ,y B , z B is the point coordinate of the buoy system; T BW is the homogeneous transformation matrix of the buoy system in the world coordinate system, where R BW is the element of the 3x3 rotation matrix; P BW is the element of the 3x1 translation vector; similarly, the coordinate transformation of the autonomous underwater robot system in the buoy system coordinate system is: Among them, x A ,y A , z A is the point coordinate of the autonomous underwater robot system; T AB is the homogeneous transformation matrix of the autonomous underwater robot system in the buoy system coordinate system; Among them, R AB is the element of the 3x3 rotation matrix; P AB The elements of the 3x1 translation vector; The coordinate transformation of the autonomous underwater robot system in the world coordinate system is: Thereby obtaining the relative position of the autonomous underwater robot system and the buoy system.

8. An underwater docking method, characterized in that: The method is used for the split AUV system according to claim 5 and comprises the following steps: Step 1: Using the ultra-short baseline USBL beacon and the ultra-short baseline USBL transponder beacon, the position coordinates of the autonomous underwater robot system relative to the buoy system are obtained; Step 2: The autonomous underwater robot system is brought close to the buoy system, and the Ax axis of the autonomous underwater robot system coordinate system is in the same direction as the Bx axis of the buoy system coordinate system; Step 3: When the visual positioning module in the autonomous underwater robot system detects the Aruco QR code plate of the buoy system 2, the posture of the autonomous underwater robot system, including the 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; Step 4: Use the PNP algorithm to solve the Aruco QR code board coordinate system O 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 are used to obtain the position coordinates of the autonomous underwater robot system relative to the buoy system, and the position of the autonomous underwater robot system is controlled to remain 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 distance measurement 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 10 cm, the magnetic locator in the autonomous robot system is turned on, and the autonomous robot continues to be controlled to approach the buoy system; Step six, finally complete the docking.

9. A following and cable obstacle avoidance method, characterized in that: The method is used for the underwater positioning method according to claim 6, comprising the following steps: The autonomous underwater robot system and the buoy system achieve bidirectional following through collaborative control: the two maintain the same direction and speed, and the cable drum motor is controlled to keep the cable at a length of L = R + Δ and in a loose 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 a feasible passage above and below the obstacle, the system will initiate a cooperative obstacle avoidance strategy; dynamically control the autonomous underwater vehicle system to maintain a safe threshold distance R' < Rb from the obstacle, and at the same time select the upper channels A and B for three-dimensional path planning based on multi-sensor fusion data, and adjust the cable length in real time to avoid the risk of the cable being entangled with the obstacle.

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