A smart recycling method for mother and daughter ships

Abstract

This invention discloses an intelligent recovery system for mother and daughter ships and its recovery method. The intelligent recovery system includes a mother ship and at least one daughter ship. The mother ship includes a hull, a hull frame, and a hull body. The hull includes left and right hollow floating materials. The hull frame connects the hull and the hull body. The hull body is a rectangular waterproof hull. The inner sides of the left and right hollow floating materials and the lower part of the rectangular waterproof hull body form a receiving space for recovering the daughter ship. The daughter ship's hull is set to a first color. The mother ship captures an image from directly in front of it using a camera, identifies the daughter ship based on a color recognition algorithm and the first color, determines the azimuth angle of the daughter ship relative to the mother ship, and then combines this with the distance between the mother and daughter ships to obtain the Cartesian coordinates of the daughter ship relative to the mother ship. Based on the mother ship's attitude angle and the daughter ship's Cartesian coordinates relative to the mother ship, the mother ship controls the PWM of a brushless motor to adjust the speed, achieving a dual-loop control of position and angle, thereby controlling the mother ship to move towards the daughter ship to complete the recovery operation. This invention can efficiently complete the recovery task.

Description

Technical Field

[0001] This invention relates to the field of mother-daughter ship technology, and specifically to an intelligent recovery method for mother-daughter ships. Background Technology

[0002] A mother ship is a unique maritime transportation and operation system widely used in various fields such as marine engineering, transportation, search and rescue, and scientific research. A mother ship system typically consists of a mother ship and one or more daughter ships. The mother ship serves as the main control and support platform, providing support such as energy, navigation, and communication, while the daughter ships perform specific tasks under the command of the mother ship.

[0003] Currently, mother ship technology is developing rapidly. Through continuous technological innovation and practical application, mother ship systems have significantly improved the efficiency and safety of maritime operations, providing strong technical support for marine engineering, military, scientific research and environmental monitoring, and have broad application prospects and important practical significance.

[0004] Despite significant progress in existing mother-daughter ship technology, some shortcomings and challenges remain. The main issues include the following:

[0005] (1) Insufficient level of automation:

[0006] Existing mother-daughter ship systems have certain shortcomings in terms of automation and intelligence. Many operations still rely on manual intervention, resulting in low operational efficiency, susceptibility to human error, and increased operational risks and costs.

[0007] (2) Limited collaborative work capabilities:

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

[0009] (3) Difficulty in identifying the recovery target:

[0010] In complex marine environments, identifying and locating recovery targets (such as lost equipment and supplies) is difficult, and existing technologies are unable to complete this task efficiently and accurately, affecting overall recovery efficiency.

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

[0012] Some recovery targets may be located in complex seabed topography or inaccessible areas, and the existing mother ship system has limited operational capabilities, making it difficult to complete highly challenging recovery tasks. Summary of the Invention

[0013] The purpose of this invention is to provide an intelligent recycling method for mother and daughter ships, enabling the mother ship to sail to the daughter ship to complete the recycling operation.

[0014] The first aspect of the present invention provides an intelligent recovery mother-daughter ship, comprising: a mother ship and at least one daughter ship;

[0015] The mother ship comprises a lower hull, a mid-section hull frame, and an upper hull. The hull includes port and starboard hollow buoyancy members to provide the required buoyancy. The hull frame connects the hull and the hull, and includes four carbon fiber hollow tubes arranged in a grid pattern. The two transverse carbon fiber hollow tubes at the front and rear connect the port and starboard hollow buoyancy members, and the two vertical carbon fiber hollow tubes at the left and right connect the two transverse carbon fiber hollow tubes at the front and rear. The hull is a rectangular waterproof hull, located on the two vertical carbon fiber hollow tubes at the front and starboard.

[0016] 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. The inside of the left and right hollow floats and the bottom of the rectangular waterproof hull form a receiving space for recovering the daughter ship. A mechanical door is also installed on the transversely arranged carbon fiber hollow tube at the rear. The mechanical door is used to fix the recovered daughter ship and move the daughter ship together.

[0017] The sub-boat is driven by a DC motor, and its hull is set to the first color.

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

[0019] The mother ship and the daughter ship communicate through the first and second communication modules to achieve parameter feedback and information transmission. The distance between the mother ship and the daughter ship is measured through the first and second UWB modules, and the attitude angles of each ship are measured through the first and second gyroscopes, respectively. The mother ship takes a picture of the front of the ship with a camera, identifies the daughter ship based on the color recognition algorithm and the first color, determines the azimuth angle of the daughter ship relative to the mother ship, and then obtains the Cartesian coordinates of the daughter ship relative to the mother ship by combining the distance between the mother ship and the daughter ship.

[0020] The mother ship controls the brushless motor's PWM to adjust the speed based on the mother ship's attitude angle and the daughter ship's Cartesian coordinates relative to the mother ship, 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 also equipped with power supplies and voltage regulators, which convert the power supply voltage into the voltage required by each module.

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

[0023] In some embodiments, the mother ship control chip and the daughter ship control chip are STM32F103 series chips, which have two different control systems built in and are interconnected.

[0024] In some embodiments, the brushless motor and the DC motor are driven and controlled by an ESC and an L298N, respectively.

[0025] In some embodiments, the mother ship has autonomous navigation capability. Under the control of the mother ship control chip, it achieves surface navigation based on set commands or automatic paths through a first gyroscope, a brushless motor, and a path tracking control algorithm. The daughter ship has autonomous navigation and self-positioning capability. It uses a second gyroscope to perceive its own attitude and position based on its own state and completes navigation behavior under the control of the daughter ship control chip.

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

[0027] The mother ship sends commands to the daughter ship through the first and second communication modules, and controls the course of the daughter ship.

[0028] In the recovery state, the mother ship automatically contacts and closes with the pre-set 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 each equipped with a remote control module connected to the mother ship's control chip and the daughter ship's control chip, respectively, to enable remote control operation.

[0030] In some embodiments, the mother ship captures an image of its front using a camera, identifies the daughter ship based on a color recognition algorithm and a first color, determines the azimuth angle of the daughter ship relative to the mother ship, and then combines this with the distance between the mother and daughter ships to obtain the Cartesian coordinates of the daughter ship relative to the mother ship, including:

[0031] The mothership uses cameras to capture images of what is directly in front of it.

[0032] Based on a first color, a color threshold range is set to identify whether there is a first color patch in the image that meets the set color threshold range. If not, the mother ship searches for the daughter ship by controlling the brushless motor. If so, the first color patch is the daughter ship. The coordinates of the center point of the identified daughter ship are compared with the coordinates of the center point of the image. If the difference between the two is within a certain threshold range, the azimuth angle of the daughter ship relative to the mother ship is determined according to the attitude angle of the mother ship. The Cartesian coordinates of the daughter ship relative to the mother ship are obtained by combining the distance between the mother and daughter ships. Otherwise, the mother ship rotates by controlling the brushless motor to make the difference between the two 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 sub-ship.

[0034] In some embodiments, the mother ship controls the brushless motor's PWM to adjust its speed based on the mother ship's attitude angle and the daughter ship's Cartesian coordinates relative to the mother ship, thereby achieving a dual-loop control of position and angle. This controls the mother ship to move towards the daughter ship to complete the recovery operation, including:

[0035] The distance between the ships is determined based on the Cartesian coordinates of the sub-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 pod relative to the mother ship, and the yaw angle is determined by combining the attitude angle of the mother ship. Then, the incremental PI algorithm is used to output the incremental PWM differential control of the left and right brushless motors to realize the angle loop.

[0037] This allows the mother ship to be guided toward the daughter ship, thus completing the recovery operation.

[0038] In some embodiments, the mother ship also controls the rotation of the child ship according to the attitude angle of the child ship so that the hull of the child ship is flush with the hull of the mother ship.

[0039] According to a second aspect of the present invention, a recycling method is provided, applied to the intelligent recycling mother-daughter ship described in any one of the first aspects, the method comprising:

[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 respective attitude angles through the first gyroscope and the second gyroscope.

[0041] The mother ship takes a picture of the front of it with a camera, identifies the daughter ship based on a color recognition algorithm and the first color, determines the azimuth angle of the daughter ship relative to the mother ship, and then obtains the Cartesian coordinates of the daughter ship relative to the mother ship by combining the distance between the mother and daughter ships.

[0042] The mother ship controls the rotation of the daughter ship according to the attitude angle of the daughter ship so that the hull of the daughter ship is level with the hull of the mother ship, which facilitates recovery;

[0043] The mother ship controls the brushless motor's PWM to adjust the speed based on the mother ship's attitude angle and the daughter ship's Cartesian coordinates relative to the mother ship, thereby controlling the mother ship to sail towards the daughter ship to complete the recovery operation.

[0044] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

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

[0046] By introducing advanced artificial intelligence and automatic control technologies, the sub-ships can achieve autonomous navigation, mission planning and execution, reducing reliance on human intervention and improving 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 ship and 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 localization technologies:

[0050] By applying advanced image processing technology, the sub-vessel's ability to identify and locate recovery targets in complex marine environments is improved, ensuring the efficient completion of recovery missions.

[0051] 4. Simplify recycling operations:

[0052] The design incorporates more flexible recovery tools, using mechanical doors to secure the smaller boats and then moving them together to achieve the combined mother-daughter boat function. This allows the smaller boats to complete challenging recovery tasks in complex terrain and hard-to-reach areas, improving overall recovery efficiency.

[0053] In summary, this 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 intelligent recovery mother-daughter ship systems. Attached Figure Description

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

[0055] Figure 2 A block diagram of a sub-ship control system provided in an embodiment of this application;

[0056] Figure 3 A SolidWorks model diagram of a mother ship provided in this application embodiment;

[0057] Figure 4 This application provides a schematic diagram of a disassembled mother ship structure.

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

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

[0060] Figure 7 A mother ship pressure diagram provided for an embodiment of this application;

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

[0062] Figure 9 This is a schematic diagram of a test target detection algorithm provided in an embodiment of this application;

[0063] Figure 10 This is a code diagram of a Keil project recycling function provided for an embodiment of this application. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this invention.

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

[0066] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0067] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; 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 not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," and "third" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0068] This application provides an intelligent recovery method for mother and daughter ships to complete the task of recovering the daughter ship, mainly including:

[0069] 1. Mothership structural design

[0070] 1.1 SolidWorks Model Design

[0071] The mother ship is driven by two brushless motors with good control performance; it uses special hollow floating material as the main hull of the mother ship; the hull frame is made of carbon fiber hollow tubes, which are strong, reliable, lightweight and corrosion resistant; the hull is designed as a rectangular waterproof hull, and the entire circuit system, sensors and control modules of the hull are installed inside the cabin. Figure 3 For the completed SolidWorks model of the mothership, Figure 4 This is a breakdown diagram of the mother ship's structure.

[0072] Specifically, the mother ship includes a hull at the bottom, a hull frame in the middle, and a hull at the top; the hull includes hollow floats on both sides to provide the required buoyancy; the hull frame connects the hull and the hull and includes four carbon fiber hollow tubes arranged in a grid pattern, of which the two transversely arranged carbon fiber hollow tubes at the front and rear connect the left and right hollow floats, and the two vertically arranged carbon fiber hollow tubes on the left and right connect the two transversely arranged carbon fiber hollow tubes at the front and rear; the hull is a rectangular waterproof hull compartment set on the two vertically arranged carbon fiber hollow tubes on the left and right sides.

[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. The inside of the left and right hollow floats and the bottom of the rectangular waterproof hull form a receiving space for recovering the sub-ships. A mechanical door is also installed on the transversely arranged carbon fiber hollow tube at the rear. The mechanical door is used to fix the recovered sub-ships and move the sub-ships together.

[0074] 1.2 Calculation of Mother Ship Parameters

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

[0076] Table 1 Mother Ship Parameters

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

[0078] 1.3 Calculation of Hydrodynamic Characteristics and Feasibility Analysis of the Model

[0079] The design speed of the mother ship is 1 m / s. Using STAR CCM+ software, the frictional resistance, residual resistance, and total resistance of this device are calculated, and relevant curves are plotted. Figure 5 , Figure 6 and Figure 7 As shown.

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

[0081] 2 Hardware Circuit Design and Component Selection

[0082] The mother ship is driven by two highly controllable brushless motors; an OpenMV camera is used for visual sensing to achieve precise positioning and recovery of the daughter ship; a 14.4V 25C lithium battery powers the entire system, and a voltage regulator converts the power supply voltage to the voltage required by each module; the daughter ship and 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's circuit board 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 crucial parameter in the control system is the feedback signal. Accurate recovery requires real-time parameters of the hull: yaw angle and the relative coordinates of the hull vessel within the mother ship's camera field of view. The yaw angle is measured by a high-precision gyroscope. The main controller acquires the angle feedback parameter by communicating with the sensor via IIC and serial port. The hull distance is measured using a UWB ranging module, with an angle ranging from 10cm to 1km, suitable for ultra-long-distance position parameter feedback. The main controller acquires the signal by communicating with the module via serial port. The relative bearing of the hull vessel to the mother ship is determined using OpenMV. OpenMV processes the images captured by the camera to obtain the hull vessel's relative Cartesian coordinates within the field of view, which are then fed back to the main controller via serial port communication. Thus, all feedback signals are fed back to the main controller 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 are two different control systems, but they are interconnected. The control components use ST's STM32F103 series chips, which are low-cost, high-performance, and have a high processing speed of up to 72MHz. They also feature built-in Flash, ADC, hardware serial port, and hardware IIC, offering excellent cost-effectiveness. The actuators, namely the brushless motor and the DC motor, are driven and controlled by ESC and L298N respectively. The measurement components are the three sensor modules mentioned above. The mother ship recovery PID control system is designed as follows: the inputs are the attitude angles of the two ships and the Cartesian coordinates of the daughter ship relative to the mother ship, and the output is the PWM control of the brushless motor to achieve speed adjustment and realize position and angle dual-loop control.

[0088] 3.2 PID Algorithm Analysis

[0089] PID control algorithms are divided into positional and incremental types; we analyze both and then select the algorithm suitable for the recycling system.

[0090] 3.2.1 Position-based control algorithm

[0091] PID control law:

[0092] To facilitate computer implementation, the above equation must be transformed into a difference equation. Therefore, assuming T is the sampling period and k is the sampling number, the following approximation is made:

[0093]

[0094] Substituting the approximate expression, we obtain the positional control formula for a digital PID controller:

[0095]

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

[0097] Since the signals collected in this application are all discrete signals, the algorithm needs to be discretized. Assuming the sampling time interval is T, then 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; thus, the discretized formula is as follows:

[0098]

[0099] The proportional coefficient Kp; the integral coefficient Kp*T / Ti, which can be represented by Ki; and the differential coefficient Kp*Td / T, which can be represented by Kd. The formula can then be written in the following form:

[0100]

[0101] 3.2.2 Incremental Control Algorithm

[0102] Speed ​​closed-loop control is a process that measures the motor speed information based on the number of pulses obtained per unit time (M-method speed measurement is used here), compares it with the target value to obtain the control deviation, and then controls the deviation by proportional, integral, and derivative to make the deviation tend to zero.

[0103] Position-based control algorithm:

[0104]

[0105] It is easy to know:

[0106]

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

[0108] Therefore:

[0109]

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

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

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

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

[0114] Further analysis revealed:

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

[0116] Among them are

[0117] For ease of programming, the above formula can be further simplified to:

[0118] Δu(k)=q1e(k)+q2e(k-1)+q3e(k-2)

[0119] Among them are:

[0120]

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

[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. The calculation error or calculation accuracy issues have little impact on the calculation of the control quantity. In contrast, the position algorithm uses the accumulated values ​​of past errors, which can easily lead to large accumulation errors.

[0123] (2) Incremental algorithms output the increment of the control quantity. For example, in valve control, only the change in valve opening is output, so the impact of erroneous actions is small. If necessary, the output can be restricted or prohibited by logical judgment, which will not seriously affect the operation of the system. In contrast, the position algorithm outputs the full amount of the control quantity, so the impact of erroneous actions is large.

[0124] (3) The incremental algorithm is adopted, which makes it easy to achieve a seamless switch from manual to automatic.

[0125] (4) Using the incremental algorithm, the position algorithm u(k) = u(k-1) + Δu(k) can also be easily derived. Therefore, this application chooses the incremental algorithm and implements it in Keil, as follows: Figure 8 As shown.

[0126] 4 Sub-ship Target Recognition Algorithm

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

[0128] 5. Experimental Verification

[0129] like Figure 10 As shown, the relevant programs for the mother-daughter ship control system were written in Keil and burned onto the STM32 main control board for verification. The PID parameters were modified and debugged through a serial touch screen to observe the accuracy and stability of the system recovery.

[0130] The intelligent recovery mother-daughter ship system proposed in this application establishes a complete functional system suitable for intelligent navigation and autonomous recovery missions under controlled environments. The system can be deployed in clean indoor water tanks and other experimental environments. 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 ships can navigate and position themselves autonomously;

[0132] ②The mother ship can locate the daughter ship and sail to it to achieve recovery;

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

[0134] ④ The mother ship can recover the daughter ship and fix it in place through a mechanical door, and then move the daughter ship together with it;

[0135] ⑤ The mother ship can charge the daughter ships, thus providing energy.

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

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

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

[0139] First, the mother ship is capable of autonomous navigation independently. Under the control of the main control chip, combined with a forward-mounted attitude sensor, a brushless motor drive system, and a path tracking control algorithm, it achieves surface navigation based on set commands or automatic paths. Simultaneously, the daughter ships also possess autonomous navigation and self-positioning capabilities. Equipped with independent control modules and sensor devices, the daughter ships can adjust their attitude and perceive their position based on their own status, thereby completing initial navigation actions.

[0140] When the mother ship and the pod are separated, the mother ship can actively locate the pod and move toward it to complete the autonomous recovery operation. This process relies on the OpenMV vision recognition module to identify the pod's color features, and combines UWB ranging and mother ship attitude data to calculate the pod's relative position coordinates. Then, an incremental PI control algorithm is used to dynamically adjust 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 to achieve 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 completes the identification and proximity positioning of the daughter ship, the mechanical door structure located at the stern of the mother ship opens, guiding the daughter ship into the mother ship's recovery compartment. The daughter ship is then physically secured by an electromechanical door locking mechanism. Afterward, the mother ship can directly drive the daughter ship synchronously, avoiding the risk of the daughter ship drifting or deviating from its intended position after recovery, thus improving the overall system's operational consistency and stability.

[0143] Simultaneously, this invention also includes an energy management module for power supply from the mother ship to the daughter ship. In the recovery state, the mother ship automatically contacts and closes with a pre-set docking charging interface on the bottom of the daughter ship, allowing the mother ship's internal battery to supply power to the daughter ship through a voltage regulator module, thus enabling the daughter ship to charge while in transit and ensuring its energy endurance for the next mission.

[0144] To adapt to diverse application scenarios, the system also supports cooperative navigation based on preset paths. After receiving the coordinates of the path points, the mother ship and the daughter ships can each perform navigation control according to the path, maintaining a certain formation or independently executing a specified trajectory task. This path information can be pre-configured or dynamically sent from the remote control terminal.

[0145] In terms of control modes, both the mother ship and the daughter ship support remote control operation. Users can control the hull in real time via a host computer or Bluetooth remote control device, including multiple functions such as starting, turning, stopping, and recognition and opening. 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 course of the daughter ships. When the daughter ships need to be precisely aligned with the mother ship for recovery, collaborative operations, or attitude correction, the mother ship can issue course control commands through the communication module. The daughter ships can then adjust their thruster differential speeds according to the received commands, thereby achieving remote guidance and course correction, effectively improving the overall integrity and stability of the collaborative operations between the mother and daughter ships.

[0147] In summary, based on the above-mentioned technical design and collaborative implementation mechanism, this invention not only realizes the autonomous operation of the mother-daughter ship system throughout the entire process in an indoor water surface 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] Existing mother-daughter ship systems generally employ the following technical approaches to achieve the recovery of daughter ships from the mother ship: visual guidance systems based on QR code recognition, heading control systems based on GPS and gyroscopes, or the use of robotic arms and magnetic structures to physically recover and secure the daughter ships. While these technologies have good application results in specific scenarios, they mostly suffer from limitations such as high system complexity, strong dependence on the recognition environment, and reliance on external satellite navigation systems for positioning. The intelligent mother-daughter ship recovery method and approach provided in this application differ significantly from the above-mentioned technical solutions in their overall design philosophy, mainly in the following aspects:

[0149] The method of identifying the sub-boat is different: This application uses a color recognition algorithm combined with an OpenMV camera to realize the visual recognition of the sub-boat. By setting a specific color threshold (such as red), the target feature area is directly extracted, realizing real-time recognition 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] The relative position calculation method is different: This application uses the UWB module for ranging, and combines the target offset angle in the color recognition image with the mother ship's attitude angle to calculate the two-dimensional Cartesian coordinates of the dwarf ship relative to the mother ship, thus eliminating the dependence on GPS and making it particularly suitable for indoor or obstructed environments.

[0151] The control system architecture is different: This application adopts a dual closed-loop incremental PI control system, which dynamically adjusts the relative coordinate position and heading angle of the sub-ships, enabling the mother ship to achieve flexible navigation and angle alignment. This is different from the traditional single-loop or fixed-path control scheme, which has higher control accuracy and faster response speed.

[0152] The physical recovery structure is different: This application uses a controllable mechanical door structure designed at the stern of the mother ship to lock the daughter ship after it enters and drive the daughter ship to sail together. This is different from the traditional mechanical arm towing, floating docking or magnetic connection methods. The structure is simpler and more reliable.

[0153] The system modules are divided differently: the mother ship and the daughter ships are each equipped with independent main control chips, power systems, and communication modules, possessing both autonomous operation and mutual coordination capabilities. The system architecture has a high degree of modularity, facilitating expansion, upgrades, and deployment for experimental teaching.

[0154] Therefore, the intelligent recovery method for mother and daughter ships provided by this 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 or other identification methods that are easily obstructed or affected by signals, and can adapt to complex working environments such as indoors, lakes, and harbors.

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

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

[0158] Lightweight and stable control algorithm: The system control strategy is based on the incremental PI algorithm, which, together with the STM32 chip, achieves fast response and robust control, making it suitable for low-power embedded platforms.

[0159] Dual Adaptability for Teaching and Research: This system is open and scalable, making it suitable for applications such as university research experimental platforms, intelligent system testing and verification, and teaching demonstrations of unmanned system algorithms.

[0160] It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. In addition, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0161] It will be readily understood by those skilled in the art that the above-described embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An intelligent recycling tug-mother ship, characterized by, include: Mother ship and at least one daughter ship; The mother ship comprises a lower hull, a mid-section hull frame, and an upper hull. The hull includes port and starboard hollow buoyancy members to provide the required buoyancy. The hull frame connects the hull and the hull, and includes four carbon fiber hollow tubes arranged in a grid pattern. The two transverse carbon fiber hollow tubes at the front and rear connect the port and starboard hollow buoyancy members, and the two vertical carbon fiber hollow tubes at the left and right connect the two transverse carbon fiber hollow tubes at the front and rear. The hull is a rectangular waterproof hull, located on the two vertical carbon fiber hollow tubes at the front and starboard. 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. The inside of the left and right hollow floats and the bottom of the rectangular waterproof hull form a receiving space for recovering the daughter ship. The transversely arranged carbon fiber hollow tube at the rear is also equipped with a lockable mechanical door, which is used to fix the recovered daughter ship and move the daughter ship together. The sub-boat is driven by a DC motor, and its hull is set to the first color. The mother ship's rectangular waterproof hull is equipped with a mother ship control chip and a front-facing camera, a first communication module, a first UWB module, and a first gyroscope connected to the mother ship control chip. The daughter ship is equipped with a daughter ship control chip and a second communication module, a second UWB module, and a second gyroscope connected to the daughter ship control chip. The camera is directly facing the front of the mother ship. The mother ship and the daughter ship communicate through the first and second communication modules to achieve parameter feedback and information transmission. The distance between the mother ship and the daughter ship is measured through the first and second UWB modules, and the attitude angles of each ship are measured through the first and second gyroscopes, respectively. The mother ship takes a picture of the front of the ship with a camera, identifies the daughter ship of the first color based on a color recognition algorithm, obtains the azimuth angle of the daughter ship relative to the mother ship, and then obtains the Cartesian coordinates of the daughter ship relative to the mother ship by combining the distance between the mother ship and the daughter ship. The mother ship uses an incremental PI algorithm to implement dual closed-loop control of position and angle loops based on its attitude angle and the Cartesian coordinates of the dwarf ship relative to the mother ship. This control is achieved by adjusting the speed of the brushless motors using PWM, thus controlling the mother ship to move towards the dwarf ship to complete the recovery operation. Specifically, the position and angle loops are implemented as follows: the distance between the two ships is determined based on the Cartesian coordinates of the dwarf ship relative to the mother ship, and the position loop is implemented by outputting the PWM of the brushless motors using an incremental PI algorithm. Simultaneously, the target heading angle is determined based on the Cartesian coordinates of the dwarf ship relative to the mother ship, and the yaw angle is determined by combining this with the mother ship's attitude angle. The angle loop is then implemented by incrementally outputting the differential PWM control quantities of the left and right brushless motors using an incremental PI algorithm. The mother ship also controls the rotation of the dwarf ship based on its attitude angle to align the dwarf ship's hull with the mother ship's hull.

2. The smart recycling tug-mother ship of claim 1, wherein, The mother ship and the daughter ship are also equipped with power supplies and voltage regulators, which convert the power supply voltage into the voltage required by each module.

3. The smart recycling tug-mother ship of claim 1, wherein, There are two brushless motors, symmetrically arranged on the front horizontally arranged carbon fiber hollow tube or the rear horizontally arranged carbon fiber hollow tube, and 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 and second communication modules are 2.4G Bluetooth, and the first and second gyroscopes are MPU6050.

4. The intelligent recovery mother-daughter 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 are interconnected.

5. The intelligent recovery mother-daughter ship according to claim 1, characterized in that, The brushless motor and the DC motor are driven and controlled by an ESC and an L298N, respectively.

6. The intelligent recovery mother-daughter ship according to claim 1, characterized in that, The mother ship has autonomous navigation capabilities. Under the control of the mother ship's control chip, it achieves surface navigation based on set commands or automatic paths through the first gyroscope, brushless motor, and path tracking control algorithm. The daughter ship has autonomous navigation and self-positioning capabilities. It uses the second gyroscope to perceive its own attitude and position based on its own state and completes navigation behavior under the control of the daughter ship's control chip. The mother ship and the daughter ship support cooperative navigation based on a preset path. After receiving the coordinates of the path points, the mother ship and the daughter ship each perform navigation control according to the path, maintaining a certain formation or independently executing a specified trajectory task. The mother ship sends commands to the daughter ship through the first and second communication modules, and controls the course of the daughter ship. In the recovery state, the mother ship automatically contacts and closes with the pre-set 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 each equipped with a remote control module connected to the mother ship's control chip and the daughter ship's control chip, respectively, to enable remote control operation.

7. The intelligent recovery mother-daughter ship according to claim 1, characterized in that, The mother ship captures an image of its front using a camera. Based on a color recognition algorithm and a first color, it identifies the daughter ship and determines its azimuth relative to the mother ship. Then, combining this with the distance between the mother and daughter ships, it obtains the daughter ship's Cartesian coordinates relative to the mother ship, including: The mothership uses cameras to capture images of what is directly in front of it. Based on a first color, a color threshold range is set to identify whether there is a first color patch in the image that meets the set color threshold range. If not, the mother ship searches for the daughter ship by controlling the brushless motor. If so, the first color patch is the daughter ship. The coordinates of the identified daughter ship's center point are compared with the coordinates of the image's center point. If the difference between the two is within a certain threshold range, the azimuth angle of the daughter ship relative to the mother ship is determined based on the mother ship's attitude angle. The Cartesian coordinates of the daughter ship relative to the mother ship are obtained by combining the distance between the mother and daughter ships. Otherwise, the mother ship rotates by controlling the brushless motor to make the difference between the two 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 sub-ship.

8. A recycling method applied to the intelligent recycling mother-daughter vessel as described in any one of claims 1 to 7, 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 respective attitude angles through the first gyroscope and the second gyroscope. The mother ship takes a picture of the front of it with a camera, identifies the daughter ship based on a color recognition algorithm and the first color, determines the azimuth angle of the daughter ship relative to the mother ship, and then obtains the Cartesian coordinates of the daughter ship relative to the mother ship by combining the distance between the mother and daughter ships. The mother ship controls the rotation of the daughter ship according to the attitude angle of the daughter ship so that the hull of the daughter ship is level with the hull of the mother ship, which facilitates recovery; The mother ship controls the brushless motor's PWM to adjust speed and achieve a dual-loop system of position and angle based on the mother ship's attitude angle and the daughter ship's Cartesian coordinates relative to the mother ship. This controls the mother ship to move towards the daughter ship to complete the recovery operation. The dual-loop system of position and angle is implemented as follows: the distance between the two ships is determined based on the daughter ship's Cartesian coordinates relative to the mother ship, and the position loop is implemented by using an incremental PI algorithm to output the brushless motor's PWM. At the same time, the target heading angle is determined based on the daughter ship's Cartesian coordinates relative to the mother ship, and the yaw angle is determined by combining it with the mother ship's attitude angle. Then, the angle loop is implemented by using an incremental PI algorithm to output the incremental differential control of the left and right brushless motors' PWM. The mother ship also controls the daughter ship to rotate based on the daughter ship's attitude angle so that the daughter ship's hull is level with the mother ship's hull.

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