Intelligent recovery child-mother ship and recovery method thereof

Abstract

The invention discloses an intelligent recycling child-mother ship and a recycling method thereof. The intelligent recycling child-mother ship comprises a mother ship and at least one child ship. The mother ship comprises a ship body, a ship body framework and a ship body. The hull comprises left and right hollow floating materials; the hull framework is connected with the hull; the boat body is a cuboid waterproof cabin; a containing space is formed by the inner sides of the left and right hollow floating materials and the lower portion of the cuboid waterproof cabin and used for recycling the sub-ship. The sub-ship body is set to be in a first color; the mother ship shoots a front image through a camera, the son ship is recognized based on a color recognition algorithm and a first color, the azimuth angle of the son ship relative to the mother ship is determined, and the Cartesian coordinates of the son ship relative to the mother ship are obtained by combining the distance between the son ship and the mother ship; the mother ship controls the PWM of the brushless motor to adjust the speed according to the attitude angle of the mother ship and the Cartesian coordinate of the son ship relative to the mother ship so as to realize position and angle double rings, so that the mother ship is controlled to sail to the son ship to complete the recovery operation. The recycling task can be efficiently completed.

Description

Technical Field

[0001] The present invention relates to the technical field of mother-and-daughter ships, and in particular to an intelligent recycling mother-and-daughter ship and a recycling method thereof. Background Art

[0002] A mother-and-daughter ship is a unique marine transportation and operation system widely used in various fields such as marine engineering, transportation, search and rescue, and scientific research. A mother-and-daughter ship system typically consists of a mother ship and one or more daughter ships. The mother ship serves as the primary control and support platform, providing energy, navigation, communications, and other support. The daughter ships carry out specific tasks under the mother ship's command.

[0003] At present, the mother-daughter ship technology is developing rapidly. Through continuous technological innovation and practical application, the mother-daughter ship system has greatly improved the efficiency and safety of marine operations, provided strong technical support for marine engineering, military, scientific research and environmental monitoring, and has broad application prospects and important practical significance.

[0004] Although the existing mother-and-daughter ship technology has made significant progress, it still has some shortcomings and challenges. The main problems include the following aspects:

[0005] (1) Insufficient automation:

[0006] Existing mother-and-daughter ship systems have certain deficiencies in automation and intelligence. Many operations still require manual intervention, resulting in low efficiency and prone to human error, increasing operational risks and costs.

[0007] (2) Limited collaborative work capabilities:

[0008] The collaborative operation capability between the daughter ship and the mother ship is limited. When performing tasks, the daughter ship often needs to communicate and exchange instructions with the mother ship frequently, which not only increases the communication burden, but also reduces the flexibility and response speed of the system.

[0009] (3) Difficulty in identifying recovery targets:

[0010] In a complex marine environment, it is difficult to identify and locate recovery targets (such as lost equipment, supplies, etc.). Existing technologies are unable to complete this task efficiently and accurately, affecting the overall recovery efficiency.

[0011] (4) The recycling operation is complicated:

[0012] Some recovery targets may be located in complex seabed terrain or in inaccessible areas. The existing mother-and-daughter ship system has limited operating means and it is difficult to complete difficult recovery tasks. Summary of the Invention

[0013] The purpose of the present invention is to provide an intelligent recovery mother ship and a recovery method thereof, so that the mother ship can sail towards the daughter ship to complete the recovery operation.

[0014] According to a first aspect of the present invention, there is provided an intelligent recovery mother-daughter ship, comprising: a mother ship and at least one daughter ship;

[0015] The mother ship includes a hull at the bottom, a hull frame in the middle, and a hull at the top. The hull includes left and right hollow floats to provide the required buoyancy. The hull frame connects the hulls and includes four carbon fiber hollow tubes arranged in a well pattern. Two horizontal carbon fiber hollow tubes are connected to the left and right hollow floats, and two vertical carbon fiber hollow tubes are connected to the two horizontal carbon fiber hollow tubes. The hull is a rectangular waterproof cabin, which is installed on the two vertical carbon fiber hollow tubes.

[0016] The mothership is driven by an even number of brushless motors, symmetrically mounted on two transversely arranged carbon fiber hollow tubes at the front and rear, and located outside the left and right hollow floats. A storage space is formed inside the left and right hollow floats and below the rectangular waterproof cabin for recovering the daughter boats. A mechanical door is also installed on the rear transversely arranged carbon fiber hollow tubes to secure the recovered daughter boats and drive them along.

[0017] The daughter ship is driven by a DC motor, and the hull is set to the first color;

[0018] The mother ship's rectangular waterproof cabin is equipped with a mother ship control chip, a camera connected to the mother ship control chip, a first communication module, a first UWB module, and a first gyroscope. The daughter ship is equipped with a daughter ship control chip, a second communication module, a second UWB module, and a second gyroscope connected to the daughter ship control chip. The camera faces the front of the mother ship.

[0019] The mother ship and daughter ship communicate through the first and second communication modules to implement parameter feedback and information transmission. The distance between the mother and daughter ships is measured through the first and second UWB modules, and the attitude angles of the daughter ships are measured through the first and second gyroscopes respectively. The mother ship captures the image in front of it through a camera, identifies the daughter ship based on the color recognition algorithm and the first color, and determines the azimuth of the daughter ship relative to the mother ship. The Cartesian coordinates of the daughter ship relative to the mother ship are then obtained based on the distance between the mother and daughter ships.

[0020] The mother ship controls the PWM of the brushless motor to adjust the speed according to the mother ship's attitude angle and the Cartesian coordinates of the daughter ship relative to the mother ship to achieve a dual loop of position and angle, thereby controlling the mother ship to sail towards the daughter ship to complete the recovery operation.

[0021] In some embodiments, the mother ship and the daughter ship are further provided with a power supply and a voltage stabilizing board, and the power supply voltage is converted into the voltage required by each module through the voltage stabilizing board.

[0022] In some embodiments, there are two brushless motors, which are symmetrically arranged on the carbon fiber hollow tube arranged horizontally in the front or the carbon fiber hollow tube arranged horizontally in the rear and are located on the outside of the left and right hollow floating materials; the camera is an openmv camera, the power supply is a lithium battery, the first communication module and the second communication module are 2.4G Bluetooth, and the first gyroscope and the second gyroscope are MPU6050.

[0023] In some embodiments, the mother ship control chip and the daughter ship control chip are chips of the stm32f103 series, which have two different control systems built in, and the two different control systems are interconnected.

[0024] In some embodiments, the brushless motor and the DC motor are controlled by an electronic speed controller and an L298N driver, respectively.

[0025] In some embodiments, the mother ship has autonomous navigation capabilities. Under the control of the mother ship control chip, it uses a first gyroscope, a brushless motor, and a path tracking control algorithm to achieve surface navigation based on set instructions or automatic paths. The daughter ship also has autonomous navigation and self-positioning capabilities. It uses a second gyroscope to sense its own posture and position based on its own state, and completes navigation under the control of the daughter ship control chip.

[0026] The mother ship and daughter ships support collaborative navigation based on a preset path. After receiving the coordinates of the path points, the mother ship and daughter ships each perform navigation control according to the path, maintaining a certain formation or independently executing a specified trajectory task;

[0027] The mother ship sends instructions to the daughter ship through the first communication module and the second communication module, and the mother ship controls the heading of the daughter ship;

[0028] In the recovery state, the mother ship automatically contacts and closes the preset docking charging interface on the bottom of the daughter ship, and the mother ship supplies power to the daughter ship;

[0029] The mother ship and the daughter ship are respectively provided with remote control modules connected to the mother ship control chip and the daughter ship control chip to realize remote control operation.

[0030] In some embodiments, the mother ship captures an image directly in front of it through a camera, identifies the daughter ship based on a color recognition algorithm and a first color, determines the azimuth of the daughter ship relative to the mother ship, and then obtains the Cartesian coordinates of the daughter ship relative to the mother ship in combination with the distance between the daughter ship and the mother ship, including:

[0031] The mother ship uses a camera to capture images directly in front of it;

[0032] A color threshold range is set based on the first color to identify whether there is a first color block that meets the set color threshold range in the image; if not, the mother ship searches for the daughter ship by controlling the brushless motor; if so, the first color block is the daughter ship, and the coordinates of the identified daughter ship center point are compared with the coordinates of the image center point. If the difference between the two is within a certain threshold range, the azimuth of the daughter ship relative to the mother ship is determined based on the mother ship's attitude angle, and the Cartesian coordinates of the daughter ship relative to the mother ship are obtained in combination with the distance between the daughter and mother ships. Otherwise, the mother ship rotates by controlling the brushless motor so that the difference between the two is within a certain threshold range;

[0033] If there are multiple first color blocks that meet the set color threshold range, the largest first color block is the daughter ship.

[0034] In some embodiments, the mother ship controls the PWM of the brushless motor to adjust the speed according to the mother ship's attitude angle and the Cartesian coordinates of the daughter ship relative to the mother ship to achieve a position and angle dual loop, thereby controlling the mother ship to sail towards the daughter ship to complete the recovery operation, including:

[0035] The distance between the two ships is determined based on the Cartesian coordinates of the daughter ship relative to the mother ship, and the position loop is realized by using the incremental PI algorithm to output the PWM of the brushless motor;

[0036] The target heading angle is determined based on the Cartesian coordinates of the daughter ship relative to the mother ship, and the yaw angle is determined in combination with the mother ship's attitude angle. The incremental PI algorithm is then used to output the PWM differential control increments of the left and right brushless motors to implement the angle loop.

[0037] This controls the mother ship to sail towards the daughter ship and completes the recovery operation.

[0038] In some of the embodiments, the mother ship further controls the daughter ship to rotate according to the attitude angle of the daughter ship so that the hull of the daughter ship is flush with the hull of the mother ship.

[0039] According to a second aspect of the present invention, there is provided a recovery method, which is applied to the intelligent recovery mother ship according to any one of the first aspects, and the method comprises:

[0040] The mother ship and the daughter ship measure the distance between them through the first UWB module and the second UWB module, and measure their attitude angles through the first gyroscope and the second gyroscope respectively;

[0041] The mother ship captures the image directly in front of it through a camera, identifies the daughter ship based on the color recognition algorithm and the first color, and determines the azimuth of the daughter ship relative to the mother ship. Then, the Cartesian coordinates of the daughter ship relative to the mother ship are obtained based on the distance between the daughter ship and the mother ship.

[0042] The mother ship controls the daughter ship to rotate according to its attitude angle so that the daughter ship's hull is flush with the mother ship's hull, making it easier to recover;

[0043] The mother ship controls the PWM of the brushless motor to adjust the speed according to the mother ship's attitude angle and the Cartesian coordinates of the daughter ship relative to the mother ship to achieve a dual loop of position and angle, thereby controlling the mother ship to sail towards the daughter ship to complete the recovery operation.

[0044] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0045] 1. Improve the level of automation and intelligence:

[0046] Advanced artificial intelligence and automatic control technologies are introduced to achieve autonomous navigation, mission planning and execution of sub-ships, reduce dependence on human intervention, and improve operational efficiency and accuracy.

[0047] 2. Enhance collaborative work capabilities:

[0048] By improving the communication protocol and data processing algorithm between the mother ship and the daughter ship, the collaborative operation capability of the mother-daughter ship system is enhanced, enabling the daughter ship to perform tasks more autonomously and efficiently while maintaining real-time collaboration and information sharing with the mother ship.

[0049] 3. Improve target recognition and positioning technology:

[0050] Advanced image processing technology is applied to improve the daughter ship's ability to identify and locate recovery targets in complex marine environments, ensuring the efficient completion of recovery missions.

[0051] 4. Simplify recycling operations:

[0052] A more flexible recovery tool is designed, which secures the daughter vessel with a mechanical door and drives it along, realizing the mother-daughter combination. This allows the daughter vessel to complete difficult recovery tasks in complex terrain and inaccessible areas, improving overall recovery efficiency.

[0053] In summary, the present invention not only solves the main problems in the prior art, but also provides a solid technical foundation and guarantee for the further development and application of the intelligent recovery mother-daughter ship system. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A block diagram of a mother ship control system provided in an embodiment of the present application;

[0055] Figure 2 A block diagram of a daughter ship control system provided in an embodiment of the present application;

[0056] Figure 3 A solidworks model diagram of a mother ship provided in an embodiment of the present application;

[0057] Figure 4 A schematic diagram of a mother ship structure disassembly provided in an embodiment of the present application;

[0058] Figure 5 A mother ship resistance curve diagram provided in an embodiment of the present application;

[0059] Figure 6 A Kelvin wave diagram of a mother ship provided in an embodiment of the present application;

[0060] Figure 7 A mother ship pressure diagram provided in an embodiment of the present application;

[0061] Figure 8 A C language implementation diagram of an incremental PI algorithm provided in an embodiment of the present application;

[0062] Figure 9 A schematic diagram of a test target detection algorithm provided in an embodiment of the present application;

[0063] Figure 10 A Keil engineering recycling function code diagram provided for an embodiment of the present application. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.

[0065] Obviously, the drawings described below are merely examples or embodiments of the present application. Those skilled in the art can, without inventive effort, apply the present application to other similar scenarios based on these drawings. Furthermore, it is also understood that, although the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, changes in design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as an insufficiency of the content disclosed in this application.

[0066] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments unless there is a conflict.

[0067] Unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by a person of ordinary skill in the technical field to which this application belongs. The words "one", "a", "the" and the like used in this application do not indicate a limit on quantity and may indicate the singular or plural. The terms "include", "comprise", "have" and any variations thereof used in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units that are inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The word "multiple" used in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific order for the objects.

[0068] This application provides an intelligent recovery mother ship and a recovery method thereof to complete the daughter ship recovery task, mainly including:

[0069] 1. Mother ship structure design

[0070] 1.1 SolidWorks model design

[0071] The mother ship is driven by two brushless motors with good control performance; special hollow floating materials are used as the main hull of the mother ship; the hull frame uses carbon fiber hollow tubes, which are strong, reliable, lightweight and corrosion-resistant; the hull is designed as a rectangular waterproof cabin that houses the entire circuit system, sensors and control modules of the hull. Figure 3 For the built mother ship solidworks model, Figure 4 This is a breakdown diagram of the mother ship structure.

[0072] Specifically, the mother ship includes a hull located at the bottom, a hull frame located in the middle, and a body located at the top; the hull includes left and right hollow floats for providing the required buoyancy; the hull frame connects the hull and the body, including four carbon fiber hollow tubes arranged in a well shape, of which the front and rear two transversely arranged carbon fiber hollow tubes are connected to the left and right hollow floats, and the left and right two vertically arranged carbon fiber hollow tubes are connected to the front and rear two transversely arranged carbon fiber hollow tubes; the hull is a rectangular waterproof cabin, which is arranged on the two vertically arranged carbon fiber hollow tubes on the left and right.

[0073] The mother ship is driven by an even number of brushless motors, which are symmetrically arranged on two transversely arranged carbon fiber hollow tubes at the front and rear and located on the outside of the left and right hollow floats. A storage space is formed on the inside of the left and right hollow floats and under the rectangular waterproof cabin for recovering the daughter ship. A mechanical door is also provided on the transversely arranged carbon fiber hollow tube at the rear to fix the recovered daughter ship and drive the daughter ship to move together.

[0074] 1.2 Calculation of mother ship parameters

[0075] The relevant parameters of the mother ship are calculated using SolidWorks, as shown in Table 1.

[0076] Table 1 Mother ship parameters

[0077] Design draft 3.5cm Displacement 2*10^7 cubic decimeters Cruising speed 7.2km / h Maximum speed >=28.8km / h Self-sustaining power 4 days thrusters 2 quality 6867.65 grams

[0078] 1.3 Calculation of hydrodynamic characteristics and model feasibility analysis

[0079] The designed mother ship speed is 1m / s. The friction resistance, residual resistance and total resistance of the device are calculated using STAR CCM+ software and the relevant curves are drawn, as shown in the figure. Figure 5 、 Figure 6 and Figure 7 shown.

[0080] Calculations show that the water and air friction resistance of the hull when traveling at a speed of 1m / s is -0.086N, the residual resistance is -0.083N, and the total resistance is -0.169N. It can be concluded that the model has good motion performance and the structural design is feasible. The cabin is produced by 3D printing.

[0081] 2 Hardware circuit design and device selection

[0082] The mother ship is driven by two brushless motors with good controllability; an openmv camera is used for visual sensing to achieve precise positioning and recovery of the daughter ship; a 14.4V 25C lithium battery is used to power the entire system, and the power supply voltage is converted into the voltage required by each module through a voltage regulator board; the daughter ship and the mother ship communicate via 2.4G Bluetooth to achieve parameter feedback and information transmission; the mother-daughter ship system is equipped with a UWB module to measure the real-time position of the two hulls to achieve distance positioning; the daughter ship uses an MPU6050 to measure attitude, and the mother ship uses a gyroscope to measure attitude; the mother ship uses a self-designed PCB to reduce power consumption and prevent static electricity.

[0083] 3 Control system and parameter design

[0084] 3.1 Feedback signal acquisition

[0085] The most critical parameter in the control system is the feedback signal. Precise recovery requires real-time hull parameters: yaw angle and the relative coordinates of the daughter vessel within the mother vessel's camera field of view. The yaw angle is measured by a high-precision gyroscope. The main control communicates with the sensor via IIC and serial ports to acquire the angle feedback parameter. The distance to the hull is measured using a UWB ranging module, with an angle range of 10 cm to 1 km, which can be used for ultra-long-distance position parameter feedback. The main control communicates with the module via serial communication to acquire the signal. The relative position of the daughter vessel to the mother vessel is determined using OpenMV. OpenMV processes the images captured by the camera to obtain the relative Cartesian coordinates of the daughter vessel within its field of view, which are then fed back to the main control via serial communication. This ensures that all feedback signals are transmitted to the main control in real time.

[0086] 3.2 Control system design

[0087] like Figure 1 and Figure 2 As shown, the daughter ship and the mother ship have two separate control systems, but they are interconnected. The control element uses ST's stm32f103 series chip, which is low-priced, has good performance, and a processing speed of up to 72MHz. Its built-in Flash, ADC, hardware serial port, and hardware IIC offer excellent value for money. The actuators, namely the brushless motor and DC motor, are controlled by electronic speed controllers and an L298N driver, respectively. The measurement elements are the three sensor modules mentioned above. The mother ship recovery PID control system design takes as input the attitude angles of the two ships and the Cartesian coordinates of the daughter ship relative to the mother ship, and outputs PWM to control the brushless motors for speed regulation, achieving a dual position and angle loop.

[0088] 3.2PID Algorithm Analysis

[0089] PID control algorithms are divided into position type and incremental type; we analyze both separately and then select the algorithm that is suitable for the recovery system.

[0090] 3.2.1 Position control algorithm

[0091] PID control law:

[0092] To facilitate computer implementation, the above equation must be transformed into a differential equation. Therefore, assume that T is the sampling period and k is the sampling sequence number. Make the following approximation:

[0093]

[0094] Substituting the approximate expression into the position control formula of the digital PID is:

[0095]

[0096] The position u(k) of the actuator is provided, which is called the digital PID position control algorithm.

[0097] The signals collected in this application are all discrete signals, so the algorithm needs to be discretized. Assuming that the sampling time interval is T, at time k: the deviation is e(k); the integral is e(k)+e(k-1)+e(k-2)+…+e(0); the differential is (e(k)-e(k-1)) / T; so the discretized formula is as follows:

[0098]

[0099] The proportional coefficient Kp; the integral coefficient Kp*T / Ti can be expressed as Ki; the differential coefficient Kp*Td / T can be expressed as Kd. The formula can be written as follows:

[0100]

[0101] 3.2.2 Incremental control algorithm

[0102] Speed closed-loop control is a process that measures the motor's speed information based on the number of pulses obtained per unit time (the M method is used here for speed measurement), compares it with the target value, obtains the control deviation, and then controls the deviation proportionally, integrally, and differentially to make the deviation approach zero.

[0103] By position control algorithm:

[0104]

[0105] Easy to know:

[0106]

[0107] The increment satisfies: Δu(k)=u(k)-u(k-1)

[0108] So we have:

[0109]

[0110] Pwm+=Kp[e(k)-e(k-1)]+Kie(k)+Kd[e(k)-2e(k-1)+e(k-2)]

[0111] Where, e(k) is the current deviation; e(k-1) is the previous deviation; e(k-2) is the previous deviation; and Pwm represents the incremental output.

[0112] In this application, only PI control is used in the speed control closed-loop system, so the PID controller can be simplified to the following formula:

[0113] Pwm+=Kp[e(k)-e(k-1)]+Kie(k)

[0114] Further sorting out:

[0115] Δu(k)=K P [e(k)-e(k-1)]+K I e(k)

[0116] Among them are

[0117] For programming convenience, further sorting the above formula yields:

[0118] Δu(k)=q1e(k)+q2e(k-1)+q3e(k-2)

[0119] Among them are:

[0120]

[0121] Comparing the formulas and ideas of the two algorithms, it is not difficult to analyze:

[0122] (1) The incremental algorithm does not require accumulation. The determination of the control quantity increment is only related to the most recent error sampling values. Calculation errors or calculation accuracy issues have little impact on the calculation of the control quantity. However, the position algorithm uses the accumulated value of past errors, which is prone to large accumulated errors.

[0123] (2) Incremental algorithms produce increments of the control variable. For example, in valve control, only the change in valve opening is output. Misoperation has little impact. If necessary, logical judgment can be used to limit or prohibit this output without seriously affecting the system's operation. Position algorithms, on the other hand, output the full amount of the control variable, resulting in a greater impact from misoperation.

[0124] (3) The incremental algorithm is used to easily achieve impact-free switching from manual to automatic.

[0125] (4) Using the incremental algorithm, it is also easy to get the position algorithm u(k) = u(k-1) + △u(k). Therefore, this application uses the incremental algorithm and implements it on Keil. Figure 8 shown.

[0126] 4. Sub-ship target recognition algorithm

[0127] like Figure 9As shown, an OpenMV camera is used to identify and locate the smaller boat from the larger vessel. Using a color recognition algorithm, the daughter boat's hull is painted red, and identification is achieved by adjusting the camera's color threshold. A mechanical door is located in the center of the mother ship. For recovery purposes, the identified daughter boat's center coordinates are compared with the center coordinates of the image captured by the mother ship's camera. If they are within a certain threshold, the daughter boat's center coordinates are returned. Considering the complex environment, if there are multiple red blocks within the field of view, the center coordinates of the largest red block are returned. These coordinates are transmitted to the microcontroller via serial communication, allowing the mother ship to accurately navigate to the daughter boat and complete the subsequent recovery operation.

[0128] 5 Experimental Verification

[0129] like Figure 10 As shown in the figure, the mother-daughter ship control system related program is written on Keil and burned to the stm32 main control board for verification, and the PID parameters are modified and debugged through the serial port touch screen to observe the accuracy and stability of the system recovery.

[0130] The intelligent recovery mothership system proposed in this application incorporates a comprehensive set of functional systems suitable for intelligent navigation and autonomous recovery missions in a controlled environment. The system can be deployed in a clean experimental environment, such as an indoor pool. Through precise design and coordinated hardware and software control, it can achieve the following eight key functions:

[0131] ① The mother ship can navigate autonomously, and the daughter ship can navigate and position autonomously;

[0132] ② The mother ship can find the daughter ship and sail towards it to recover it;

[0133] ③ The mother ship can achieve real-time communication with the daughter ship and receive data information sent by the daughter ship during surface operations;

[0134] ④ The mother ship can recover the daughter ship and fix the daughter ship through the mechanical door, driving the daughter ship to move together;

[0135] ⑤ The mother ship can charge the daughter ship to realize energy supply;

[0136] ⑥ The daughter ship and the mother ship may travel along the prescribed path;

[0137] ⑦ Both the daughter ship and the mother ship can be remotely controlled;

[0138] ⑧The mother ship can control the direction of the daughter ship.

[0139] First, the mothership is capable of independently completing autonomous navigation tasks. Under the control of the main control chip, it combines a front-mounted attitude sensor, a brushless motor drive system, and a path-tracking control algorithm to achieve surface navigation based on set instructions or automatic paths. Simultaneously, the daughtership also has autonomous navigation and self-positioning capabilities. Equipped with independent control modules and sensor devices, the daughtership can adjust its attitude and sense its position based on its own state, thus completing preliminary navigation operations.

[0140] When the mother ship and daughter ship are separated, the mother ship can actively locate the daughter ship and navigate towards it to complete the autonomous recovery operation. This process relies on the OpenMV visual recognition module to identify the daughter ship's color characteristics, and combines UWB ranging with the mother ship's attitude data to calculate the daughter ship's relative position coordinates. Then, an incremental PI control algorithm dynamically adjusts the propulsion motor power to achieve precise approach.

[0141] A stable communication mechanism is established between the mother ship and the daughter ship, using a 2.4GHz Bluetooth module for two-way real-time information exchange. During independent operation, the daughter ship can continuously transmit collected surface operation data such as speed, attitude, and mission status back to the mother ship's main control module to support the mother ship's monitoring and management of the overall mission status.

[0142] Once the mother ship approaches and identifies and locates the daughter vessel, a mechanical door at the mother ship's stern opens, guiding the daughter vessel into the mother ship's recovery chamber and securing it with an electrically operated mechanical door lock. From then on, the mother ship can directly drive the daughter vessel in synchronized motion, eliminating the risk of the daughter vessel drifting or misaligned after recovery, and improving the operational consistency and stability of the entire system.

[0143] The invention also incorporates an energy management module for the mother ship to power the daughter ship. When recovered, the mother ship automatically connects and closes with a pre-set docking charging port on the bottom of the daughter ship. The mother ship's internal battery then powers the daughter ship via a voltage regulator module, enabling the daughter ship to charge while underway and ensuring its energy endurance for the next mission.

[0144] To accommodate diverse application scenarios, the system also supports collaborative navigation based on pre-set paths. After receiving pathpoint coordinates, the mother and daughter vessels can independently navigate according to the path, maintaining a specific formation or independently executing a designated trajectory. This path information can be pre-configured or dynamically transmitted by the remote control terminal.

[0145] In terms of control mode, both the mother ship and the daughter ship support remote control. Users can use a host computer or Bluetooth remote control device to achieve real-time control of the hull, including starting, steering, stopping, identification and opening, and other functions. They can also switch to autonomous control mode at any time to meet the needs of experimental debugging or mission takeover.

[0146] Furthermore, the system design allows the mother ship to control the heading of the daughter ship. When the daughter ship needs to precisely align with the mother ship for recovery, collaborative operations, or attitude correction, the mother ship can send heading control commands via the communication module, and the daughter ship adjusts the propeller differential speed based on the received commands, thus achieving remote guidance and heading correction, effectively improving the integrity and stability of the mother-daughter and daughter ship collaborative operations.

[0147] In summary, based on the above-mentioned technical design and collaborative implementation mechanism, the present invention not only realizes the full-process autonomous operation of the mother-and-daughter ship system in an indoor water environment, but also completes the eight core functions of the system in a modular, integrated, and reconfigurable manner, providing a feasible technical path and system framework for the research, teaching, and experimental verification of intelligent ships.

[0148] The existing mother-and-daughter ship systems generally adopt the following technical paths in the process of realizing the mother ship's recovery task of the daughter ship: such as a visual guidance system based on QR code recognition, a heading control system based on GPS and gyroscopes, or the use of robotic arms, magnetic structures, etc. to achieve the physical recovery and fixation of the daughter ship. Although the above technologies have good application effects in specific scenarios, most of them have limiting factors such as high system complexity, strong dependence on the recognition environment, and dependence on external satellite navigation systems for positioning. The intelligent recovery mother-and-daughter ship and its recovery method provided in this application are significantly different from the above technical solutions in terms of overall design concept, which is mainly reflected in the following aspects:

[0149] Different methods of sub-ship identification: This application uses a color recognition algorithm and combines it with an openmv camera to achieve visual identification of sub-ships. By setting a specific color threshold (such as red), it directly extracts the target feature area to achieve real-time identification under low power consumption and low computing power conditions. Compared with QR code or deep learning model recognition methods, the algorithm is lighter and more adaptable.

[0150] Different relative position calculation methods: This application uses the UWB module to measure distance, combines the target offset angle in the color recognition image with the mother ship's attitude angle, and calculates the two-dimensional Cartesian coordinates of the sub-ship relative to the mother ship, getting rid of the dependence on GPS, and is especially suitable for indoor or shielded environments.

[0151] Different control system architecture: This application adopts a dual closed-loop incremental PI control system to dynamically adjust the relative coordinate position and heading angle of the sub-ship, so that the mother ship can achieve flexible navigation and angle alignment. Different from the traditional single-loop or fixed path control scheme, it has higher control accuracy and faster response speed.

[0152] Different physical recovery structure: This application designs a controllable opening mechanical door structure at the rear of the mother ship, which enables the daughter ship to enter and lock and drive the daughter ship to sail as a whole. Different from the traditional mechanical arm dragging, floating docking or magnetic connection method, the structure is simpler and more reliable.

[0153] Different system modules: The mother ship and daughter ship are each equipped with independent main control chips, power systems, and communication modules, enabling both autonomous operation and collaborative collaboration. The highly modular system architecture facilitates expansion, upgrades, and experimental teaching deployment.

[0154] Therefore, the intelligent recovery mother-daughter ship and recovery method provided by the present invention achieves accurate identification, positioning, approach, and fixed recovery of the daughter ship by the mother ship without the need for external navigation assistance, and has the following advantages:

[0155] Wide range of applicable environments: It does not rely on GPS, QR codes and other identification methods that are easily blocked or affected by signals, and can adapt to complex operating environments such as indoors, lakes, and harbors.

[0156] High recognition efficiency and good control accuracy: The color recognition algorithm is combined with dual closed-loop control to achieve dynamic correction of the daughter ship's position and heading, significantly improving navigation stability and recovery accuracy.

[0157] Compact structure and modular design: The entire ship structure is made of carbon fiber and hollow floating materials, which is light and high-strength. Combined with the mechanical door recovery structure, it has good water adaptability and easy installation.

[0158] Lightweight control algorithm and stable operation: The system control strategy is based on the incremental PI algorithm, combined with the STM32 chip to achieve fast response and robust control, suitable for low-power embedded platforms.

[0159] Dual adaptability for teaching and scientific research: This system is open and scalable, and is suitable for use in scenarios such as university scientific research experimental platforms, intelligent system testing and verification, and unmanned system algorithm teaching demonstrations.

[0160] It should be noted that the various technical features of the above-described embodiments can be combined in any manner. To simplify the description, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there are no contradictions in the combination of these technical features, they should be considered to be within the scope of this specification. In addition, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0161] Those skilled in the art will readily understand that the above-described embodiments merely represent several implementation methods of the present application, and their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the invention. It should be noted that a person of ordinary skill in the art may make several variations and improvements without departing from the concept of the present application, and these variations and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be based on the appended claims.

Claims

1. An intelligent recovery mother ship, characterized in that: include: A mother ship and at least one daughter ship; The mother ship includes a hull at the bottom, a hull frame in the middle, and a hull at the top. The hull includes left and right hollow floats to provide the required buoyancy. The hull frame connects the hulls and includes four carbon fiber hollow tubes arranged in a well pattern. Two horizontal carbon fiber hollow tubes are connected to the left and right hollow floats, and two vertical carbon fiber hollow tubes are connected to the two horizontal carbon fiber hollow tubes. The hull is a rectangular waterproof cabin, which is installed on the two vertical carbon fiber hollow tubes. The mothership is driven by an even number of brushless motors, symmetrically mounted on two transversely arranged carbon fiber hollow tubes at the front and rear, and located outside the left and right hollow floats. A storage space is formed inside the left and right hollow floats and below the rectangular waterproof cabin for recovering the daughter boats. A mechanical door is also installed on the rear transversely arranged carbon fiber hollow tubes to secure the recovered daughter boats and drive them along. The daughter ship is driven by a DC motor, and the hull is set to the first color; The mother ship's rectangular waterproof cabin is equipped with a mother ship control chip, a camera connected to the mother ship control chip, a first communication module, a first UWB module, and a first gyroscope. The daughter ship is equipped with a daughter ship control chip, a second communication module, a second UWB module, and a second gyroscope connected to the daughter ship control chip. The camera faces the front of the mother ship. The mother ship and daughter ship communicate through the first and second communication modules to implement parameter feedback and information transmission. The distance between the mother and daughter ships is measured through the first and second UWB modules, and the attitude angles of the daughter ships are measured through the first and second gyroscopes respectively. The mother ship captures the image in front of it through a camera, identifies the daughter ship based on the color recognition algorithm and the first color, and determines the azimuth of the daughter ship relative to the mother ship. The Cartesian coordinates of the daughter ship relative to the mother ship are then obtained based on the distance between the mother and daughter ships. The mother ship controls the PWM of the brushless motor to adjust the speed according to the mother ship's attitude angle and the Cartesian coordinates of the daughter ship relative to the mother ship to achieve a dual loop of position and angle, thereby controlling the mother ship to sail towards the daughter ship to complete the recovery operation.

2. The intelligent recycling mother ship according to claim 1, characterized in that: The mother ship and daughter ship are also equipped with power supplies and voltage regulators, which convert the power supply voltage into the voltage required by each module through the voltage regulator.

3. The intelligent recycling mother ship according to claim 1, characterized in that: There are two brushless motors, which are symmetrically arranged on the front transverse carbon fiber hollow tube or the rear transverse carbon fiber hollow tube and located outside the left and right hollow floats; The camera is an openmv camera, the power supply is a lithium battery, the first communication module and the second communication module are 2.4G Bluetooth, and the first gyroscope and the second gyroscope are MPU6050.

4. The intelligent recycling mother ship according to claim 1, characterized in that: The mother ship control chip and the daughter ship control chip are STM32F103 series chips, which have two different control systems built in, and the two different control systems are interconnected.

5. The intelligent recycling mother ship according to claim 1, characterized in that: The brushless motor and DC motor are driven and controlled by ESC and L298N respectively.

6. The intelligent recycling mother ship according to claim 1, characterized in that: The mother ship has the ability to sail autonomously. Under the control of the mother ship control chip, it uses the first gyroscope, brushless motor and path tracking control algorithm to achieve surface navigation based on set instructions or automatic paths. The daughter ship also has the ability to sail autonomously and self-position. The second gyroscope senses the attitude and position based on its own state, and completes the navigation behavior under the control of the daughter ship control chip. The mother ship and daughter ships support collaborative navigation based on a preset path. After receiving the coordinates of the path points, the mother ship and daughter ships each perform navigation control according to the path, maintaining a certain formation or independently executing a specified trajectory task; The mother ship sends instructions to the daughter ship through the first communication module and the second communication module, and the mother ship controls the heading of the daughter ship; In the recovery state, the mother ship automatically contacts and closes the preset docking charging interface on the bottom of the daughter ship, and the mother ship supplies power to the daughter ship; The mother ship and the daughter ship are respectively provided with remote control modules connected to the mother ship control chip and the daughter ship control chip to realize remote control operation.

7. The intelligent recycling mother ship according to claim 1, characterized in that: The mother ship captures the front image through a camera, identifies the daughter ship based on the color recognition algorithm and the first color, and determines the azimuth of the daughter ship relative to the mother ship. Then, combined with the distance between the daughter ship and the mother ship, the Cartesian coordinates of the daughter ship relative to the mother ship are obtained, including: The mother ship uses a camera to capture images directly in front of it; A color threshold range is set based on the first color to identify whether there is a first color block that meets the set color threshold range in the image; if not, the mother ship searches for the daughter ship by controlling the brushless motor; if so, the first color block is the daughter ship, and the coordinates of the identified daughter ship center point are compared with the coordinates of the image center point. If the difference between the two is within a certain threshold range, the azimuth of the daughter ship relative to the mother ship is determined based on the mother ship's attitude angle, and the Cartesian coordinates of the daughter ship relative to the mother ship are obtained in combination with the distance between the daughter and mother ships. Otherwise, the mother ship rotates by controlling the brushless motor so that the difference between the two is within a certain threshold range; If there are multiple first color blocks that meet the set color threshold range, the largest first color block is the daughter ship.

8. The intelligent recycling mother ship according to claim 1, characterized in that: The mother ship controls the PWM of the brushless motor to adjust the speed according to the mother ship's attitude angle and the Cartesian coordinates of the daughter ship relative to the mother ship, realizing the position and angle dual loop, thereby controlling the mother ship to sail towards the daughter ship to complete the recovery operation, including: The distance between the two ships is determined based on the Cartesian coordinates of the daughter ship relative to the mother ship, and the position loop is realized by using the incremental PI algorithm to output the PWM of the brushless motor; The target heading angle is determined based on the Cartesian coordinates of the daughter ship relative to the mother ship, and the yaw angle is determined in combination with the mother ship's attitude angle. The incremental PI algorithm is then used to output the PWM differential control increments of the left and right brushless motors to implement the angle loop. This controls the mother ship to sail towards the daughter ship and completes the recovery operation.

9. The intelligent recycling mother ship according to claim 8, characterized in that: The mother ship also controls the daughter ship to rotate according to the attitude angle of the daughter ship so that the daughter ship hull is flush with the mother ship hull.

10. A recycling method, applied to the intelligent recycling mother ship according to any one of claims 1 to 9, characterized in that: The method includes: The mother ship and the daughter ship measure the distance between them through the first UWB module and the second UWB module, and measure their attitude angles through the first gyroscope and the second gyroscope respectively; The mother ship captures the image directly in front of it through a camera, identifies the daughter ship based on the color recognition algorithm and the first color, and determines the azimuth of the daughter ship relative to the mother ship. Then, the Cartesian coordinates of the daughter ship relative to the mother ship are obtained based on the distance between the daughter ship and the mother ship. The mother ship controls the daughter ship to rotate according to its attitude angle so that the daughter ship's hull is flush with the mother ship's hull, making it easier to recover; The mother ship controls the PWM of the brushless motor to adjust the speed according to the mother ship's attitude angle and the Cartesian coordinates of the daughter ship relative to the mother ship to achieve a dual loop of position and angle, thereby controlling the mother ship to sail towards the daughter ship to complete the recovery operation.

Images