Control system and control method for movement of unmanned sailboat

Abstract

The invention provides a control system and a control method for unmanned sailboat motion, and belongs to the technical field of unmanned sailboat control. Comprising a controller, an IO module, a plurality of sensors, a plurality of relays, a water pushing motor driver, a water pushing motor, a rudder motor driver, a rudder motor with a band-type brake, a sail rising and falling motor driver, a sail rising and falling motor with a band-type brake, a sail rotating motor driver, a sail rotating motor with a band-type brake and an energy supply module. The controller is connected with a plurality of relays through an IO module, and the relays are connected with a water pushing motor driver, a rudder motor driver, a sail rising and falling motor driver and a sail rotating motor driver respectively and used for controlling power-on and power-off of the drivers. The drivers are connected with the corresponding water pushing motors, the rudder motors, the sail rising and falling motors and the sail rotating motors respectively and used for driving all the motors. The energy consumption of the sailing boat is reduced.

Description

Technical Field

[0001] This invention belongs to the field of unmanned sailboat control technology, and particularly relates to a motion control system and control method for unmanned sailboats. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Unmanned sailboats are sailboats that do not rely on human operation of the sails, but rather on controllers to automatically control the sails and move automatically under the force of the wind. They have broad application prospects in ocean exploration, hydrological information collection, route exploration, patrol and surveillance, and intelligence gathering. The working environment of unmanned sailboats determines that their energy sources are limited. They cannot replenish their energy by docking at shore in the open ocean, and generally only solar and wind power can be used by the sailboats.

[0004] The existing technology has the following drawbacks: Firstly, there are ships with hybrid solar and wind power systems. These are ships with specially designed hull shapes that combine wind propulsion, solar propulsion, and power supply systems. The specially designed hull shape can maximize the area of ​​solar panels to obtain a large amount of solar power. However, this technology can only solve the problem of energy source acquisition and does not provide energy-saving methods when the sailboat is operating.

[0005] Secondly, besides using energy to overcome wind and water resistance and provide power, some of a sailboat's energy is wasted as heat when electrical components are idle. Furthermore, some flexible components on the hull also consume energy during vibration. However, current control systems use sail lines and rudders to control the sail angle. In this approach, the billowing and vibration of the sails caused by the wind, as well as the vibration caused by the elasticity of the sail lines themselves, all contribute to additional energy consumption by frequently and instantaneously increasing the rudder's drive current.

[0006] Finally, some existing technical solutions use soft sails on unmanned sailboats, which can reduce the load on the sail angle adjustment mechanism and simplify the design of the operating system. However, soft sails have a limited lifespan, leading to the need for periodic shore maintenance. To compensate for this, some technical solutions use rigid sails instead of soft sails, but this increases the load requirements on the drive components. A common solution is to use hydraulic components for drive. Although hydraulic components can provide extremely high force and torque output, they suffer from slow response speed, continuous energy consumption, low energy efficiency, the need for regular oil changes, and high maintenance costs. The slow response speed also slows down the sail angle adjustment speed, resulting in increased errors in the sailboat's path tracking. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, this invention proposes a motion control system and control method for unmanned sailboats. It is designed for unmanned sailboats with a single rigid sail that can be raised and lowered and without a flexible connection structure. With the goal of reducing the energy consumption of sailboats, it features fully electric control and electric drive, no hydraulic components, safety and reliability, and high energy utilization.

[0008] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions: In a first aspect, the present invention discloses a motion control system for an unmanned sailboat, including a controller, an I / O module, several sensors, several relays, a water propulsion motor driver, a water propulsion motor, a rudder motor driver, a rudder motor with a brake, a sail lifting and lowering motor driver, a sail lifting and lowering motor with a brake, a sail rotation motor driver, a sail rotation motor with a brake, and a power supply module. The controller is connected to several relays via an I / O module. These relays are connected to the water propulsion motor driver, rudder motor driver, sail raising and lowering motor driver, and sail rotation motor driver, respectively, to control the power-on and power-off of these drivers. The drivers are connected to their respective water propulsion motors, rudder motors, sail raising and lowering motors, and sail rotation motors, respectively, to drive each motor. The power supply module provides power to the electrical components in the sailboat. The controller is also connected to several sensors to acquire the sailboat's status and control the motors' motion based on that status.

[0009] In a further technical solution, the controller includes two CAN buses. The first CAN bus is connected to the plurality of sensors, and the second CAN bus is connected to the sail lifting motor driver, the sail rotation motor driver, and the rudder motor driver.

[0010] In a further technical solution, the controller is also connected to a remote communication device for communicating with the shore station. The controller transmits the acquired sailboat status to the shore station system through the remote communication module, and receives task instructions issued by the shore station system through the remote communication module. It then parses and plans the task instructions to form motion control instructions, and then performs motion control on the motor.

[0011] Further technical solutions also include a sail lowering position switch, a sail raising position switch, a sail rotation positive limit switch, a sail rotation negative limit switch, and a sail zero position switch. The sail lowering position switch signal and the sail raising position switch signal are respectively connected to two digital input interfaces of the sail raising and lowering motor driver; the sail rotation positive limit switch signal, the sail rotation negative limit switch signal, and the sail zero position switch signal are respectively connected to three digital input interfaces of the sail rotation motor driver.

[0012] In a further technical solution, the power supply module includes a battery, a solar panel, and a DC voltage regulator module. The solar panel provides charging capability for the battery, and the battery provides power to all electrical components in the sailboat through the DC voltage regulator module.

[0013] A further technical solution includes several sensors, including a positioning and orientation sensor, a current meter, a wind speed and direction sensor, and a light sensor, used to acquire data on the sailboat's status, including battery power, battery voltage, sailboat position, sailboat attitude, rudder angle, sail lifting and lowering status, sail angle, water propulsion motor speed, wind speed, wind direction, and light intensity.

[0014] Secondly, the present invention discloses a motion control method for unmanned sailboats, comprising: Obtain battery level information and sailboat status data; The battery power is divided into five levels. The first to fourth levels correspond to the progressively increasing motion control cycles, and the fifth level turns off all motor drives. The power selection strategy is determined based on the sailboat's status. The sailboat uses the water propulsion motor only when it is in a near-shore state, an emergency collision avoidance state, or when it receives instructions from the shore station to use the water propulsion motor. In other states, the sails provide power. The process of providing power to the sail includes energy-saving control strategies for the sail rotation motor and rudder motor. Specifically, based on the length of the motion control cycle, the sail rotation motor driver or rudder motor driver is powered on, controlled, and powered off only once in each motion control cycle. The water propulsion motor adopts an energy-saving control strategy, which determines whether it is in an emergency collision avoidance state, whether it is in a shore station remote control state, and the shore station heartbeat cycle, and controls the water propulsion motor to run or power off.

[0015] A further technical solution, wherein the power-on, motion control, and power-off operation of the sail rotation motor driver or rudder motor driver includes: Upon power-on, the relay coil engages after receiving the power-on signal, powering on the rudder motor driver or sail rotation motor driver, enabling the driver to enter the enabled state, and controlling the sail rotation motor brake or rudder motor brake to release. Motion control involves detecting the current of the sail rotation motor driver or rudder motor driver. When the current increase exceeds a specific value, a motion start command is sent to the sail rotation motor driver or rudder motor driver. During the motion, the motion status information fed back by the driver is read. When the target position is reached and the motor speed is 0, a power-off process is initiated. In the power-down process, the sail motor driver or rudder motor driver controls the brake of the sail motor or rudder motor to tighten, and detects the current of the sail motor driver or rudder motor driver. When the current decrease exceeds a certain value, the sail motor driver or rudder motor driver is de-enabled. The controller sends a power-down signal to the second or fourth digital output interface of the IO module, the second or fourth intermediate relay coil is released, and the sail motor driver or rudder motor driver is powered down.

[0016] Further technical solutions also include an energy-saving control strategy for the sail landing motor. The power-on process is that the controller powers on the sail landing motor driver through the IO module and relay and configures the mode and parameters of the sail landing motor driver, so that the driver enters the enabled state. At the same time, the controller causes the sail landing motor driver to control the sail landing motor brake to release. The motion control process involves detecting the current of the sail landing motor driver. When the current increase exceeds a specific value, the controller sends a motion start command to the sail landing motor driver. During the motion, the controller reads the position switch signal. When the target position switch is triggered, the motor stops moving. The controller reads the motor speed and waits for the motor speed to reach 0 before entering the power-off process. The power-down process is as follows: the controller causes the sail landing motor driver to control the sail landing motor brake to engage. The controller detects the current of the sail landing motor driver. When the current decrease exceeds a certain value, the controller causes the sail landing motor driver to exit the enabled state. The controller sends a power-down signal to the third digital output interface of the IO module, the third intermediate relay coil is released, and the sail landing motor driver is powered down.

[0017] Further technical solutions include a control strategy for sail lowering decisions. If the current battery level is at level 5, the sail lowering operation is executed; if the current battery level is not at level 5 and the current light intensity is below a specific value, the sail lowering operation is executed; if there is no wind, the sail is not turned or lowered, and the sail remains upright; if there is wind, but it is less than the safe wind speed level given by the shore station, the distance between the sailboat's current position and the virtual anchor point is determined to be greater than the safe distance. If it is less than the safe distance, the sail rotation motor is controlled to rotate the sail to the angle of minimum wind force; if it is greater than or equal to the safe distance, the sail angle is adjusted to reduce the distance between the sailboat and the virtual anchor point; if there is wind, but it is greater than the safe wind speed level given by the shore station, the sail rotation motor is controlled to return to zero before lowering the sail.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention achieves a fully electric control and fully electric drive motion control system by replacing hydraulic components with a high-power motor, eliminating the need for regular maintenance of hydraulic components, which is beneficial for ocean voyages. At the same time, it improves the response speed of the motion control system, which can make sail angle adjustment faster and reduce the path tracking error of unmanned sailboats. This invention uses an electric drive component instead of a hydraulic component, avoiding the problems of continuous energy consumption and heat generation of the hydraulic component. The control method with energy-saving strategy adopted in this solution can effectively reduce the heating time of the electric drive component, thereby reducing the waste of the sailboat's already limited energy, improving energy utilization, and enabling the sailboat to achieve long-duration ocean voyages relying solely on solar and wind power.

[0019] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1 This is a schematic diagram of the motion control system for unmanned sailboats described in Embodiment 1 of the present invention.

[0022] Figure 2 This is a flowchart of the motor energy-saving control strategy for determining the remaining battery power as described in Embodiment 2 of the present invention.

[0023] Figure 3 This is a flowchart of the power selection strategy described in Embodiment 2 of the present invention.

[0024] Figure 4 This is a flowchart illustrating the energy-saving control strategy for the sail rotation motor and rudder motor described in Embodiment 2 of the present invention.

[0025] Figure 5 This is a flowchart of the energy-saving control strategy for the sail lifting and lowering motor described in Embodiment 2 of the present invention. Detailed Implementation

[0026] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0027] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0028] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0029] Definitions: Unmanned sailboats: These are sailboats that do not rely on human intervention to operate the sail angle, but instead rely on a controller to automatically control the sail angle and travel along a planned route under the influence of wind.

[0030] Controller: This can be a computing device such as a computer, industrial control computer, or microcontroller, on which control system software and strategies run.

[0031] IO module: This typically refers to a module with digital input (DI) or digital output (DO) interfaces. The DI interface converts switching signals into digital signals for the controller to read, while the DO interface converts the controller's digital signals into switching signals for controlling external devices. The IO module used in this invention only utilizes the DO interface. The switching signals that the controller needs to read are connected to the DI port of the motor driver, and then the controller reads them directly from the driver via the CANopen protocol.

[0032] CAN bus: A commonly used fieldbus, it is a field communication bus defined close to the physical layer. Only one application layer protocol can run on a single CAN bus. Devices on the CAN bus must have a CAN interface to connect to the CAN bus.

[0033] CANopen protocol: It is an application layer protocol that runs on the CAN bus and is commonly used in the communication of motion controllers and motor drivers.

[0034] NMEA2000 protocol: It is an application layer protocol that runs on the CAN bus and is commonly used in the communication of sensors and equipment in the marine field.

[0035] RS485 bus: A commonly used fieldbus, it is a field communication bus defined close to the physical layer. Only one application layer protocol can run on an RS485 bus. Devices on an RS485 bus must have an RS485 interface to connect to the RS485 bus.

[0036] Modbus protocol: It is an application layer protocol that can run on buses such as RS485 and RS232, and is widely used in the communication of various industrial control equipment.

[0037] Intermediate relay: In this invention, it is used to solve the problem that the DO port cannot directly drive the motor driver. The current of the DO port is generally not too large, while the operating current of the motor driver is usually very large, so it is not possible to drive it directly using the DO port. Therefore, an intermediate relay is added to ensure effective control of the motor driver.

[0038] Motor driver: Motors typically require a large current when running, and the controller cannot directly drive the motor. Therefore, a motor driver is usually used to drive the motor. In addition to providing drive current to the motor, modern drivers usually provide rich interfaces, including communication interfaces (such as supporting the CANopen protocol) and IO interfaces (used to read limit switch signals or control the holding brake).

[0039] Water propulsion motor: A motor used to drive a propeller.

[0040] Steering motor: There is a rudder at the stern of the boat, which is used to assist in turning the sailboat. The steering motor is used to drive the rudder to rotate to a specified angle.

[0041] Sail Lifting and Lowering Motor: Since the sail controlled in this project is installed on a mast that can be raised or lowered, a sail lifting and lowering motor is needed to drive the mast to be raised or lowered. When the mast is raised, the sail is in the raised state and the sail surface is perpendicular to the deck. When the mast is lowered, the sail is in the lowered state and the sail surface lies on the deck.

[0042] Sail Rotor Motor: When the mast is raised, the sail can be propelled by the wind. However, in order for the sailboat to move in a specific direction, a sail rotary motor is needed to adjust the angle of the sail, allowing the sail to rotate around the mast to the appropriate angle. This, combined with the adjustment of the rudder, will allow the sailboat to move in the designated direction.

[0043] Position switches, limit switches, and zero-position switches refer to sensors that provide switching signals. Installed at designated locations, they trigger the switch when the sail reaches a specific position during operation, generating a switching signal. For example, the sail lowering position switch is installed at the exact position the sail touches when it is lowered; the sail raising position switch is installed at the exact position the sail touches when it is raised; the sail rotation positive and negative limit switches are installed at the positive and negative limit positions of the sail rotation joint; and the sail zero-position switch is installed at the zero point position of the sail.

[0044] Holding brake: Some motors may include a holding brake, which prevents the motor from rotating passively after a power outage when the brake is engaged, and allows the motor to rotate when the brake is disengaged.

[0045] BMS: Battery Management System. It has a communication interface, and the controller can obtain battery parameters such as charge, voltage, current, and error information by communicating with the BMS.

[0046] Example 1 In one or more embodiments, a motion control system for unmanned sailboats is disclosed, such as Figure 1As shown, it includes a controller, an I / O module, several sensors, four relays, a water propulsion motor driver, a water propulsion motor, a rudder motor driver, a rudder motor with a brake, a sail raising and lowering motor driver, a sail raising and lowering motor with a brake, a sail rotating motor driver, a sail rotating motor with a brake, a sail lowering position switch, a sail raising position switch, a sail rotating positive limit switch, a sail rotating negative limit switch, a sail zero position switch, a remote communication device, and a power supply module. The controller is connected to several relays via an I / O module. These relays are connected to the water propulsion motor driver, rudder motor driver, sail lift-and-lower motor driver, and sail rotation motor driver, respectively, to control the power-on and power-off of these drivers. The drivers are connected to their respective water propulsion motors, rudder motors, sail lift-and-lower motors, and sail rotation motors to drive each motor. The power supply module provides power to the electrical components in the sailboat. The controller is also connected to several sensors to acquire the sailboat's status and control the motors' motion based on that status.

[0047] Preferably, the controller includes two CAN buses. The first CAN bus is connected to the plurality of sensors, and the second CAN bus is connected to the sail lift motor driver, the sail swivel motor driver, and the rudder motor driver. The first CAN bus adopts the NMEA2000 protocol to facilitate future connection with more marine sensors to expand the sailboat's functionality. The second CAN bus adopts the CANopen protocol.

[0048] Specifically, the controller implements digital output through the IO module. The IO module has 4 digital output signals (DO port). The usage is as follows: the first digital output signal controls the power-on and power-off of the two water propulsion motor drivers through the first intermediate relay; the second digital output signal controls the power-on and power-off of the rudder motor driver through the second intermediate relay; the third digital output signal controls the power-on and power-off of the sail lifting and lowering motor driver through the third intermediate relay; and the fourth digital output signal controls the power-on and power-off of the sail rotation motor driver through the fourth intermediate relay.

[0049] The relays include a first intermediate relay, a second intermediate relay, a third intermediate relay, and a fourth intermediate relay. The first intermediate relay is connected to a first water propulsion motor driver, which is connected to the first water propulsion motor. The first intermediate relay is also connected to a second water propulsion motor driver, which is connected to the second water propulsion motor. The second intermediate relay is connected to a rudder motor driver, whose motor interface is connected to the rudder motor, and whose DO port is connected to the rudder motor brake. The third intermediate relay is connected to a sail lowering motor driver, whose motor interface is connected to the sail lowering motor, whose DO port is connected to the sail lowering motor brake, whose first DI port is connected to the sail lowering position switch, and whose second DI port is connected to the sail raising position switch. The fourth intermediate relay is connected to a sail rotation motor driver, whose motor interface is connected to the sail rotation motor, whose DO port is connected to the sail rotation motor brake, whose first DI port is connected to the sail rotation positive limit switch, whose second DI port is connected to the sail rotation negative limit switch, and whose third DI port is connected to the sail zero position switch.

[0050] The two water-driven motor drivers mentioned above are configured such that the first water-driven motor driver is used to drive the first water-driven motor, and the second water-driven motor driver is used to drive the second water-driven motor. The first water-driven motor and the second water-driven motor are brushless DC motors.

[0051] The servo motor driver is used to drive the servo motor, which is a high-power DC servo motor. The brake control line of the servo motor is connected to the DO port of the servo motor driver.

[0052] The sail lift motor driver is used to drive the sail lift motor, which is a high-power DC servo motor. The brake control line of the sail lift motor is connected to the DO port of the sail lift motor driver.

[0053] The sail rotary motor driver is used to drive the sail rotary motor, which is a high-power DC servo motor. The brake control line of the sail rotary motor is connected to the DO port of the sail rotary motor driver.

[0054] The controller controls the brakes of the sail lifting motor, sail rotating motor, and rudder motor by controlling the digital output interface (DO port) signals of the corresponding motor drivers through the CANopen protocol.

[0055] The sail lowering position switch is installed in a triggerable position after the rigid sail has been lowered to the designated position, and the sail raising position switch is installed in a triggerable position after the rigid sail has been raised to the designated position. The sail lowering position switch signal and the sail raising position switch signal are respectively connected to two digital input interfaces (DI ports) of the sail raising and lowering motor driver. The controller reads the sail lowering position switch signal and the sail raising position switch signal from the sail raising and lowering motor driver via the CANopen protocol.

[0056] The aforementioned sail rotation positive limit switch is installed at the positive limit position of the sail rotation joint, the sail rotation negative limit switch is installed at the negative limit position of the sail rotation joint, and the sail zero position switch is installed at the zero point position of the sail rotation joint. The sail rotation positive limit switch signal, sail rotation negative limit switch signal, and sail zero position switch signal are respectively connected to the three digital input interfaces (i.e., DI ports) of the sail rotation motor driver. The controller reads the sail rotation positive limit switch signal, sail rotation negative limit switch signal, and sail zero position switch signal from the sail rotation motor driver via the CANopen protocol. Preferably, the controller communicates with the shore station via a remote communication device, which provides remote communication capabilities for the control system. The controller transmits the acquired sailboat status to the shore station system through the remote communication module, and receives task instructions from the shore station system through the remote communication module. It then parses and plans the task instructions to form motion control instructions, and finally controls the motors accordingly.

[0057] The power supply module includes a battery, a solar panel, and a DC voltage regulator module. The solar panel provides charging capability for the battery, and the battery provides power to all electrical components in the sailboat through the DC voltage regulator module.

[0058] The controller also has one RS485 interface, which connects to the battery BMS communication interface via RS485 bus and uses the Modbus protocol to read battery parameters, including battery voltage, battery level, and battery error information.

[0059] It should be understood that the controller, IO module, and BMS can all be connected to this RS485 bus, with the controller acting as the Modbus master and the IO module and BMS acting as Modbus slaves.

[0060] Further technical solutions include several sensors, including positioning and orientation sensors, current meters, wind speed and direction sensors, and light sensors, to provide the control system with sensing capabilities and acquire data on the sailboat's status, including battery power, battery voltage, sailboat position, sailboat attitude, rudder angle, sail lifting and lowering status, sail angle, water propulsion motor speed, wind speed, wind direction, and light intensity.

[0061] It should be understood that the motion control system described in this embodiment and the control methods described in other embodiments are designed for unmanned sailboats characterized by: the use of a single rigid sail instead of a soft sail (soft sails generally require ropes, while rigid sails do not); the rigid sail is mounted on a mast that can automatically raise and lower; solar panels are located on both the fore and aft sides of the sail, as well as on the deck; and batteries are located inside the cabin. The structural features of this type of sailboat are not the focus of this invention; such structure and connections are existing technology and will not be described further here.

[0062] In this invention, the controller can be a programmable computing device such as a computer, microcontroller, single-board computer, PLC, or soft PLC. If the computer does not have a CAN interface, its USB or TCP interface can be used to expand the CAN interface by pairing it with a USB-to-CAN or TCP-to-CAN adapter. If the computer does not have an RS485 interface, its USB or TCP interface can be used to expand the RS485 interface by pairing it with a USB-to-RS485 or TCP-to-RS485 adapter. Alternatively, the RS485 interface and RS485 bus in the solution can be replaced with a TCP interface and an Ethernet port running the Modbus TCP protocol. In this case, the controller, I / O module, and battery management system (BMS) need to have Ethernet ports that support TCP communication and support the Modbus TCP protocol.

[0063] Example 2 In one or more embodiments, a motion control method for an unmanned sailboat is disclosed, including: a motor energy-saving control strategy based on the remaining battery power; a power selection strategy; an energy-saving control strategy for the sail rotation motor and the rudder motor; an energy-saving control strategy for the sail raising and lowering motor; a sail lowering decision strategy at the end of the sailing mission; and an energy-saving control strategy for the water propulsion motor.

[0064] The specific steps of the motion control method for unmanned sailboats include the following: Step S1: Obtain battery power information and sailboat status data; Step S2: Divide the battery power into five levels. The first to fourth levels correspond to progressively increasing motion control cycles, and the fifth level is to turn off all motor drivers. The remaining battery power corresponding to the first to fifth levels is arranged from high to low.

[0065] Motor energy-saving control strategies determined by the remaining battery power, such as Figure 2As shown, the specific process includes the following: The controller detects the battery power and divides the battery power into 5 levels from high to low. If it is level 5, all motor drives are turned off. For the other levels, different motion control cycles are adopted. In each cycle, only the sail rotation motor and rudder motor are controlled once to adjust their positions to the new target positions. The motion control cycle of level 1 is the shortest and the motion control cycle of level 4 is the longest.

[0066] Step S3: Determine the power selection strategy based on the sailboat's state. Only when the sailboat's state meets the requirements of near-shore state, emergency collision avoidance state, or receiving instructions from the shore station to use the water propulsion motor, the sailboat's power uses the energy-saving control strategy of the water propulsion motor. In other states, only the sails provide power. The process of providing power to the sail includes an energy-saving control strategy for the sail rotation motor and rudder motor. Based on the length of the motion control cycle, the sail rotation motor driver or rudder motor driver is powered on, controlled, and powered off only once in each motion control cycle.

[0067] like Figure 3 As shown, the power selection strategy specifically includes the following process: the water propulsion motor is used only in the following three states: 1) near-shore state, i.e., when the unmanned sailboat leaves and returns to port; 2) emergency collision avoidance state, i.e., in the non-near-shore state, when it is expected that the planned route of the unmanned sailboat will collide with an obstacle on the water surface; 3) in any other situation when the received shore station command specifies the use of the water propulsion motor. Apart from the aforementioned three states, the unmanned sailboat relies solely on its sails for power. The controller raises the sails via the sail raising and lowering actuator and adjusts the sails to the appropriate angle via the sail rotating actuator to obtain suitable wind thrust. Simultaneously, the controller adjusts the rudder to the appropriate angle via the rudder actuator to control the sailboat's direction of travel. Both the sail angle and rudder angle are calculated by the controller based on the current wind speed and direction, ocean current speed and direction, current sailboat position, and the sailboat's target heading.

[0068] Specifically, such as Figure 4 As shown, the energy-saving control strategy for the sail rotation motor and rudder motor includes the following process: The controller determines the duration of a single motion control cycle based on the battery level. In each motion control cycle, the sail rotation motor driver or rudder motor driver is powered on, controlled, and powered off only once.

[0069] The power-on drive process is as follows: the controller sends a power-on signal to the second or fourth digital output interface of the IO module, the second or fourth intermediate relay coil is energized, the rudder motor driver or sail rotation motor driver is powered on, the controller sets the sail rotation motor driver or rudder motor driver to position mode through the CANopen protocol, configures the target position parameters, and enables the driver, and the controller controls the sail rotation motor driver or rudder motor driver to release the sail rotation motor brake or rudder motor brake through the CANopen protocol.

[0070] The motion control process is as follows: The controller detects the current of the sail rotation motor driver or rudder motor driver through the CANopen protocol. When the current increase exceeds a specific value Ia, the controller sends a motion start command to the sail rotation motor driver or rudder motor driver through the CANopen protocol. During the motion, the controller reads the motion status information fed back by the driver through the CANopen protocol. When the target position is reached and the motor speed is 0, the power-off process is entered.

[0071] The power-down process is as follows: The controller sends a command through the CANopen protocol to cause the sail rotation motor driver or rudder motor driver to control the brake of the sail rotation motor or rudder motor to tighten. The controller detects the current of the sail rotation motor driver or rudder motor driver through the CANopen protocol. When the current decrease exceeds a specific value Ib, the controller uses the CANopen protocol to de-enable the sail rotation motor driver or rudder motor driver. The controller sends a power-down signal to the second or fourth digital output interface of the IO module. The second or fourth intermediate relay coil is released, and the sail rotation motor driver or rudder motor driver is powered down.

[0072] Furthermore, the energy-saving control strategies for the sail rotator motor and rudder motor are implemented separately for each motor in the control system. The specific current change values ​​Ia and Ib are obtained by the controller through separate table lookups for each motor. These specific current change values ​​Ia and Ib are related to the current wind speed, wind direction, ocean current speed, ocean current direction, sail angle, and sailboat attitude; the data tables were obtained through experimental testing.

[0073] Energy-saving control strategies for sail lifting motors, such as Figure 5As shown, the specific process includes the following: When the sail needs to be raised or lowered, the sail raising and lowering position switches detect the position signal. If the position signal of the corresponding target position has been triggered, it is directly determined that the sail raising and lowering motor has reached its position. If the position signal of the corresponding target position has not been triggered, the power-on process is initiated. The steps are as follows: The controller sends a power-on signal to the third digital output interface of the IO module. The third digital output interface powers on the sail raising and lowering motor driver through the third intermediate relay. The controller configures the sail raising and lowering motor driver to speed mode through the CANopen protocol, configures the motion parameters according to the target position, and then puts it into the enabled state. The controller controls the sail raising and lowering motor brake to be released by the sail raising and lowering motor driver through the CANopen protocol. The motion control process is as follows: The controller detects the current of the sail lift motor driver via the CANopen protocol. When the current increase exceeds a specific value Ic, the controller sends a motion start command to the sail lift motor driver via the CANopen protocol. During motion, the controller reads the stop switch signal via the CANopen protocol. When the target stop switch is triggered, the motor stops moving, and the controller reads the motor speed and waits for the motor speed to reach 0 before entering the power-down process. The power-down process steps are as follows: The controller uses the CANopen protocol to control the sail lift motor driver to engage the brake; the controller detects the current of the sail lift motor driver via the CANopen protocol; when the current decrease exceeds a specific value Id, the controller uses the CANopen protocol to de-enable the sail lift motor driver; the controller sends a power-down signal to the third digital output interface of the IO module; the third intermediate relay coil is released; and the sail lift motor driver is powered down. The aforementioned specific values ​​Ic and Id of the current change are obtained by the controller through a separate lookup table. The specific values ​​Ic and Id of the current change are related to the current wind speed, wind direction, ocean current speed and direction, sail lift status, and sailboat attitude. The data table was obtained through experimental testing.

[0074] In this embodiment, the energy-saving effects achieved by the control strategies for sail raising and lowering, sail rotation, etc., include the following aspects: First, the energy-saving strategy mentions that only one power-on, motion control, and power-off operation is performed in a motion control cycle. This means that the frequency of motion control is limited by the motion control cycle, which is equivalent to determining the degree of energy saving based on the remaining power. Secondly, because the sail and rudder experience significant resistance, this control system uses a high-power motor instead of the commonly used hydraulic drive device. The control strategy only powers on the corresponding motor via an intermediate relay when needed, and immediately de-energizes it after the movement is complete, minimizing the power-on time of the drive system and preventing limited power from being wasted in the enabled state of the motor drive system. Since the actuator requires a large current even just to keep the load stationary in the enabled state, this embodiment does not simply disable the actuator, but completely de-energizes the intermediate relay and the actuator. This avoids the power consumed by the intermediate relay coil in maintaining its engaged state, and also avoids wasting power maintaining the actuator in the disabled state (although the power consumption in the disabled state is smaller than in the enabled state, the cumulative power consumption during long-term unmanned sailing is still significant).

[0075] In addition, in this embodiment, the brake is released only after the power-on process is enabled, and the brake is locked only after the power-off process is deactivated. This control sequence is to prevent the sail and rudder from reversing under the huge resistance of wind and water. Once reversal occurs, electricity is required to drive the sail and rudder to rotate back to the correct position.

[0076] Furthermore, during the power failure process, the brake is only deactivated after it engages and the current decrease exceeds a specific value Ib. This is also to prevent load rollback. In motion control, the usual practice is to use a fixed or variable delay between enabling and brake control. This method can lead to load rollback under heavy loads. In situations with abundant power, this problem is not a concern. However, sailboats have limited power. Therefore, this solution does not use a time delay to determine the timing of deactivating the brake and engaging the brake. Instead, it uses current detection to make the judgment. This method can prevent load rollback and has a rapid response.

[0077] The sail lowering decision strategy at the end of a sailing mission includes the following process: Record the sailboat's position at the end of the mission as a virtual anchor point, and repeatedly perform subsequent judgments, ensuring each cycle lasts at least 3 minutes; if the current battery level is at level 5, perform the sail lowering operation; if the current battery level is not at level 5 and the current light intensity is below a certain value, perform the sail lowering operation; if there is no wind, do not turn or lower the sail, and keep the sail upright; if there is wind, but it is less than the safe wind speed level given by the shore station, determine if the distance between the sailboat's current position and the virtual anchor point is greater than the safe distance. If it is less than the safe distance, control the sail rotator motor to turn the sail to the angle of least wind force; if it is greater than or equal to the safe distance, adjust the sail angle to reduce the distance between the sailboat and the virtual anchor point; if there is wind, but it is greater than the safe wind speed level given by the shore station, control the sail rotator motor to return to zero, and then lower the sail. If the decision to lower the sail is made during the cyclic judgment, the loop will exit and the strategy will end after the sail lowering is completed.

[0078] The energy-saving aspect of the sail-lowering decision strategy is to maintain the sails upright as much as possible to maximize sunlight exposure, hence the mention of a specific value for sunlight intensity in the strategy description. Additionally, the strategy aims to avoid lowering the sails as much as possible, since lowering the sails and raising them again would also consume additional electricity.

[0079] The energy-saving control strategy for water propulsion motors specifically includes the following process: When the system is using a water-powered propulsion motor for driving, this strategy will be executed to make a judgment. First, if the current state is an emergency collision avoidance state, the water-powered propulsion motor will continue to run. Otherwise, it will be determined whether the current state is under shore station remote control. If so, it will be determined whether the shore station heartbeat has been interrupted for more than 3 heartbeat cycles. If it has not been interrupted, the water-powered propulsion motor will continue to run. If it has been interrupted, or if the current state is not under shore station remote control, the controller will send a power-down signal to the first digital output interface of the IO module, and the first intermediate relay coil will be released to power down the water-powered propulsion motor driver.

[0080] It should be understood that the electrical energy consumed by a water-powered motor to propel a sailboat is far greater than that consumed by a sailboat to propel it. Therefore, the strategy mentioned above only allows the use of water-powered motors in three situations. The energy-saving aspect of the water-powered motor control strategy involves detecting the heartbeat of the shore station; if no heartbeat is received for more than three heartbeat cycles, the water-powered motor automatically stops operating. In the open ocean, without this strategy, sailboats may drift erratically under poor communication conditions, wasting electricity on incorrect routes and requiring additional power to correct them.

[0081] The descriptions of each embodiment in the above embodiments have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A motion control system for unmanned sailboats, characterized in that, Includes a controller, I / O modules, several sensors, several relays, a water propulsion motor driver, a water propulsion motor, a rudder motor driver, a rudder motor with a brake, a sail lifting and lowering motor driver, a sail lifting and lowering motor with a brake, a sail rotation motor driver, a sail rotation motor with a brake, and a power supply module. The controller is connected to several relays via an I / O module. These relays are connected to the water propulsion motor driver, rudder motor driver, sail raising and lowering motor driver, and sail rotation motor driver, respectively, to control the power-on and power-off of these drivers. The drivers are connected to their respective water propulsion motors, rudder motors, sail raising and lowering motors, and sail rotation motors, respectively, to drive each motor. The power supply module provides power to the electrical components in the sailboat. The controller is also connected to several sensors to acquire the sailboat's status and control the motors' motion based on that status.

2. The motion control system for an unmanned sailboat as described in claim 1, characterized in that, The controller includes two CAN buses. The first CAN bus is connected to the plurality of sensors, and the second CAN bus is connected to the sail lifting motor driver, the sail rotating motor driver, and the rudder motor driver.

3. The motion control system for an unmanned sailboat as described in claim 1, characterized in that, The controller is also connected to a remote communication device for communicating with the shore station. The controller transmits the acquired sailboat status to the shore station system through the remote communication module, and receives task instructions issued by the shore station system through the remote communication module. It then parses and plans the task instructions to form motion control instructions, and then performs motion control on the motor.

4. A motion control system for an unmanned sailboat as described in claim 1, characterized in that, It also includes a sail lowering position switch, a sail raising position switch, a sail rotation positive limit switch, a sail rotation negative limit switch, and a sail zero position switch. The sail lowering position switch signal and the sail raising position switch signal are respectively connected to two digital input interfaces of the sail raising and lowering motor driver; the sail rotation positive limit switch signal, the sail rotation negative limit switch signal, and the sail zero position switch signal are respectively connected to three digital input interfaces of the sail rotation motor driver.

5. A motion control system for an unmanned sailboat as described in claim 1, characterized in that, The power supply module includes a battery, a solar panel, and a DC voltage regulator module. The solar panel provides charging capability for the battery, and the battery provides power to all electrical components in the sailboat through the DC voltage regulator module.

6. A motion control system for an unmanned sailboat as described in claim 1, characterized in that, The sensors include a positioning and orientation sensor, a current meter, a wind speed and direction sensor, and a light sensor, used to acquire the sailboat's status, including battery power, battery voltage, sailboat position, sailboat attitude, rudder angle, sail lifting and lowering status, sail angle, water propulsion motor speed, wind speed, wind direction, and light intensity data.

7. A motion control method for unmanned sailboats, characterized in that, include: Obtain battery level information and sailboat status data; The battery power is divided into five levels. The first to fourth levels correspond to the progressively increasing motion control cycles, and the fifth level turns off all motor drives. The power selection strategy is determined based on the sailboat's status. The sailboat uses the water propulsion motor only when it is in a near-shore state, an emergency collision avoidance state, or when it receives instructions from the shore station to use the water propulsion motor. In other states, the sails provide power. Among them, the process of the sail providing power includes energy-saving control strategies for the sail rotation motor and rudder motor. Specifically, based on the length of the motion control cycle, the sail rotation motor driver or rudder motor driver is powered on, controlled, and powered off only once in each motion control cycle. The water propulsion motor adopts an energy-saving control strategy to determine whether it is in an emergency collision avoidance state, whether it is in a shore station remote control state, and the shore station heartbeat cycle, and controls the water propulsion motor to run or shut down.

8. The motion control method for an unmanned sailboat as described in claim 7, characterized in that, The power-on drive involves the relay receiving a power-on signal, causing its coil to engage, which powers on the rudder motor driver or sail rotation motor driver, enabling the driver to enter the enabled state and controlling the sail rotation motor brake or rudder motor brake to release. The motion control detects the current of the sail rotation motor driver or rudder motor driver. When the current increase exceeds a certain value, a motion start command is sent to the sail rotation motor driver or rudder motor driver. During the motion, the motion status information fed back by the driver is read. When the target position is reached and the motor speed is 0, a power-off process is initiated. When the power is off, the sail motor driver or rudder motor driver controls the brake of the sail motor or rudder motor to tighten, detects the current of the sail motor driver or rudder motor driver, and when the current decrease exceeds a certain value, the sail motor driver or rudder motor driver is deactivated. The controller sends a power-off signal to the second or fourth digital output interface of the IO module, the second or fourth intermediate relay coil is released, and the sail motor driver or rudder motor driver is powered off.

9. The motion control method for an unmanned sailboat as described in claim 7, characterized in that, It also includes an energy-saving control strategy for the sail landing motor. The power-on process is that the controller powers on the sail landing motor driver through the IO module and relay and configures the mode and parameters of the sail landing motor driver, so that the driver enters the enabled state. At the same time, the controller causes the sail landing motor driver to control the sail landing motor brake to be released. The motion control process involves detecting the current of the sail landing motor driver. When the current increase exceeds a specific value, the controller sends a motion start command to the sail landing motor driver. During the motion, the controller reads the position switch signal. When the target position switch is triggered, the motor stops moving. The controller reads the motor speed and waits for the motor speed to reach 0 before entering the power-off process. The power-down process is as follows: the controller causes the sail landing motor driver to control the sail landing motor brake to engage. The controller detects the current of the sail landing motor driver. When the current decrease exceeds a certain value, the controller causes the sail landing motor driver to exit the enabled state. The controller sends a power-down signal to the third digital output interface of the IO module, the third intermediate relay coil is released, and the sail landing motor driver is powered down.

10. The motion control method for an unmanned sailboat as described in claim 7, characterized in that, It also includes a control strategy for sail lowering decisions. If the current battery level is at level 5, the sail lowering operation is performed; if the current battery level is not at level 5 and the current light intensity is below a certain value, the sail lowering operation is performed; if there is no wind, the sail is not turned or lowered, and the sail remains upright; if there is wind and the wind speed is less than the safe wind speed level given by the shore station, it is determined whether the distance between the sailboat's current position and the virtual anchor point is greater than the safe distance. If it is less than the safe distance, the sail rotation motor is controlled to rotate the sail to the angle of minimum wind force; if it is greater than or equal to the safe distance, the sail angle is adjusted to reduce the distance between the sailboat and the virtual anchor point. If there is wind and it exceeds the safe wind speed level given by the shore station, control the sail rotation motor to return to zero before lowering the sail.

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