Testing device and control method for zero-speed rolling reduction of ship

Abstract

The invention relates to a test device and a control method for zero-speed rolling reduction of a ship. The test device comprises a ship model, a forced rolling device, a sensor device and a fin rolling reduction device, the forced rolling device is used for driving the ship model to generate rolling motion; the sensor device is used for monitoring attitude information of the ship model in rolling motion; the control device generates an action decision of the fin stabilization device through the strategy network; the fin stabilization device flaps to a specified angle and frequency according to the action decision generated by the control device; wherein the sensor device monitors the posture change of the ship model and the actual flapping angle of the fin stabilization device in real time and feeds back the posture change and the actual flapping angle to the control device, and the control device evaluates the effectiveness of the current strategy according to the feedback of the sensor device: if the stabilization effect meets the requirement, the current strategy is enhanced, otherwise, the strategy network is updated; and the control action of the fin stabilizer is further optimized. The test device is simple in structure and control method, and stabilization can be realized under different sea conditions and dynamic changes of ship rolling.

Description

Technical Field

[0001] The invention relates to the technical field of ship roll reduction, and in particular to a test device and a control method for ship zero-speed roll reduction. Background Art

[0002] With the development and utilization of marine resources, the safety of ship transportation, offshore platform service and operation and maintenance has received more and more attention and importance.

[0003] Ships and other vessels will experience six-degree-of-freedom swaying motions under the influence of external environmental loads such as wind, waves and currents, including roll, pitch, bow roll, sway, sway and heave. The roll motion of ships has a large amplitude, a short period and a large acceleration, which will directly affect the comfort of personnel and the working capacity of instruments and equipment. Severe and large rolls can also cause the ship to capsize and threaten the safety of the ship, such as stability and buoyancy. The roll moment of a ship is much smaller than the pitch moment, so the technology of reducing the roll of the ship is feasible and can achieve good results. At the same time, when the ship is floating freely or anchored, and the offshore platform is being installed and operated, it is also susceptible to obvious roll motions caused by the action of waves. Although there are currently methods such as bilge keels, lift-type anti-roll fins, and anti-roll water tanks to actively or passively control the roll of ships, thereby reducing the roll motion of ships. However, the traditional lift-type anti-roll fin forms an angle of attack by rotating the spanwise axis, and uses the lift effect under speed to achieve anti-roll, but its own motion amplitude is small, so when the ship is at zero speed, it will lose lift and the anti-roll ability will be greatly weakened. The anti-roll tank has a good anti-roll effect when it is near its resonant frequency, but when the wave frequency deviates from its resonant frequency, the anti-roll ability is greatly reduced.

[0004] Tank model test is a common method to study the motion performance of ships in waves and anti-rolling technology. By installing anti-rolling devices on the ship model and conducting experiments in a tank environment, the motion performance of the real ship in waves can be obtained and the anti-rolling devices can be tested.

[0005] However, the roll drive device in the traditional ship model roll reduction test device is large in size, complex in structure and has high purchase cost. In addition, the roll reduction efficiency of the traditional roll reduction control algorithm and strategy also has certain defects, making it difficult to achieve roll reduction under different sea conditions and dynamic changes in ship roll. Summary of the invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a test device and a control method for ship zero-speed roll reduction, which has a simple structure and can achieve roll reduction under different sea conditions and dynamic changes of ship roll.

[0007] In order to achieve the above object, the present invention adopts the following technical solution: A test device for reducing the rolling of a ship at zero speed, comprising a ship model and a control device, wherein a forced rolling device, a sensor device and a fin anti-rolling device are installed on the ship model; The forced rolling device is used to drive the ship model to produce rolling motion; The sensor device is used to monitor the attitude information of the ship model during the rolling motion, including the rolling angle, the rolling angular velocity and the rolling acceleration, and send the information to the control device; The control device is used to generate an action decision of the fin anti-roll device through a strategy network according to the received ship model attitude information; The fin stabilization device flaps to the specified angle and frequency according to the action decision generated by the control device; The sensor device monitors the changes in the ship model's posture and the actual flapping angle of the fin anti-roll device in real time and feeds back to the control device. The control device evaluates the effectiveness of the current strategy based on the feedback from the sensor device: if the anti-roll effect meets the requirements, the current strategy is strengthened; otherwise, the strategy network is updated to further optimize the control action of the fin anti-roll device.

[0008] Furthermore, the forced roll device includes a stepper motor, a first transmission device and a slider, the slider is slidably connected to the ship model; the stepper motor is fixed to the ship model and connected to the first transmission device, the first transmission device is connected to the slider, and is used to drive the slider to move laterally on the ship model.

[0009] Furthermore, the first transmission device includes a belt, a pulley and a guide wheel, the pulley and the guide wheel are respectively hinged to the ship model, the belt is wound around the pulley and the guide wheel, the stepper motor is driven and connected to the pulley, and the slider is fixed to the belt.

[0010] Furthermore, the first transmission device also includes a slide rail, which is fixed to the ship model, and the slider is nested on the slide rail and slidably connected to the slide rail.

[0011] Furthermore, the sensor device includes an accelerometer and a gyroscope. The accelerometer is arranged on the side of the ship model for measuring the roll acceleration of the ship model; the gyroscope is arranged at the mid-longitudinal section of the ship model for measuring the roll angle and roll angular velocity of the ship model.

[0012] Furthermore, the fin roll stabilization device includes a fin drive motor, a second transmission device and a flapping fin. The fin drive motor is fixed to the ship model and connected to the second transmission device. The second transmission device is connected to the flapping fin for driving the flapping fin to flap repeatedly.

[0013] Furthermore, the second transmission device includes a right-angle gearbox, the driving shaft of the fin drive motor is vertically arranged, the right-angle gearbox is located below the fin drive motor, the right-angle gearbox includes a linked vertical axis and a horizontal axis, the vertical axis of the right-angle gearbox is connected to the driving shaft of the fin drive motor, and the flapping fin is connected to the horizontal axis of the right-angle gearbox.

[0014] Furthermore, two sets of fin anti-roll devices are provided, and the two sets of fin anti-roll devices are respectively arranged on the left and right sides of the ship model.

[0015] Furthermore, the control device is a PPO algorithm agent.

[0016] A control method for a test device for reducing rolling at zero speed of a ship comprises the following steps: The forced rolling device drives the ship model to produce rolling motion; The sensor device monitors the attitude information of the ship model during the rolling motion, including the rolling angle, the rolling angular velocity and the rolling acceleration, and sends the information to the control device; The control device generates an action decision of the fin anti-roll device through a strategy network according to the received ship model attitude information; The fin stabilization device flaps to the specified angle and frequency according to the action decision generated by the control device; The sensor device monitors the changes in the ship model's posture and the actual flapping angle of the fin anti-roll device in real time and feeds back to the control device. The control device evaluates the effectiveness of the current strategy based on the feedback from the sensor device: if the anti-roll effect meets the requirements, the current strategy is strengthened; otherwise, the strategy network is updated to further optimize the control action of the fin anti-roll device.

[0017] In general, the present invention has the following advantages: (1) The flapping fin anti-roll device of the present invention performs bionic control by imitating the flapping of the pectoral fins of fish, and can generate a large anti-roll moment for the ship at zero speed or low speed, thereby achieving the purpose of reducing the roll of the ship.

[0018] (2) The present invention adopts an artificial intelligence method to learn, train and control the motion logic of the fin roll stabilization device. Through an artificial intelligence algorithm based on proximal policy optimization (PPO) and using the ship model roll information as feedback, the roll stabilization motion trajectory of the flapping fins is autonomously learned to achieve ship roll stabilization control and adaptively stabilize the ship roll under conditions of different roll frequencies and roll amplitudes.

[0019] (3) By introducing a forced roll device, the present invention establishes a low-cost ship roll excitation method, which can effectively simulate the ship roll motion caused by actual waves. The artificial intelligence roll reduction model trained in a forced roll environment can be directly applied to the actual wave environment roll reduction control without the need for retraining. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the overall structure of the ship model.

[0021] Figure 2 (a) is a schematic diagram of the structure of the forced roll device.

[0022] FIG2( b ) is a schematic structural diagram of the forced roll device from another perspective.

[0023] Figure 3 It is a schematic diagram of the structure of the fin anti-roll device.

[0024] Figure 4 This is the workflow diagram of the PPO algorithm based on the flapping fin anti-roll device.

[0025] In the figure: 1 is a ship model; 2 is a forced roll device; 2-1 is a stepping motor; 2-2 is a slider; 2-3 is a slide rail; 2-4 is a belt; 2-5 is a pulley; 2-6 is a guide wheel; 2-7 is a base; 3 is a fin anti-roll device; 3-1 is a fin drive motor; 3-2 is a connecting shaft; 3-3 is a waterproof shaft sleeve; 3-4 is a gearbox base; 3-5 is a right-angle gearbox; 3-6 is a flapping fin; 4 is a gyroscope; 5 is an accelerometer. DETAILED DESCRIPTION

[0026] The present invention will be described in further detail below.

[0027] like Figure 1 , Figure 4 As shown, a test device for reducing the rolling of a ship at zero speed includes a ship model 1 and a control device. In this embodiment, the control device is a PPO algorithm intelligent agent.

[0028] The ship model 1 is equipped with a forced roll device 2, a sensor device and a fin roll reduction device 3; The forced rolling device 2 is used to drive the ship model 1 to produce rolling motion; The sensor device is used to monitor the attitude information of the ship model 1 during the rolling motion, including the rolling angle, the rolling angular velocity and the rolling acceleration, and send it to the control device; The control device is used to generate an action decision of the fin anti-roll device 3 through a strategy network according to the received attitude information of the ship model 1; The fin anti-roll device 3 flaps to a specified angle and frequency according to the action decision generated by the control device; Among them, the sensor device monitors the posture changes of the ship model 1 and the actual flapping angle of the fin anti-roll device 3 in real time and feeds back to the control device. The control device evaluates the effectiveness of the current strategy based on the feedback of the sensor device: if the anti-roll effect meets the requirements, the current strategy is strengthened; otherwise, the strategy network is updated to further optimize the control action of the fin anti-roll device 3.

[0029] Specifically, the ship model 1 includes a hull shell, a ballast block, and a constraint connection device. The hull shell is processed according to the line drawing of the target ship type, and its appearance satisfies geometric similarity with the target ship type. The interior of the hull shell is hollow for arranging other equipment. The ballast block is fixed inside the hull shell to adjust the buoyancy of the model and make its center of gravity position, weight distribution, and moment of inertia meet the target values. The constraint connection device is used to connect the ship model 1 to a pool trailer, etc., so as to prevent the ship model 1 from drifting, and can constrain the degrees of freedom of the ship model 1 such as longitudinal swing, transverse swing, and bow pitch according to needs, thereby improving the test accuracy.

[0030] The forced roll device 2 is installed at the rear of the midship, and is used to simulate the effect of waves to make the ship model 1 produce roll motion; the sensor device is installed on the deck in front of the midship, and is used to measure the roll angle, roll acceleration and other signals of the ship model 1; the fin roll reduction device 3 is installed at the midship position, and an opening is provided at the midship bilge position, which is used to extend the flapping fins 3-6 of the fin roll reduction device 3 from the inside of the hull to the outside of the hull.

[0031] As shown in Fig. 2 (a) and Fig. 2 (b), specifically, the forced rolling device 2 includes a stepper motor 2-1, a first transmission device and a slider 2-2, wherein the slider 2-2 is slidably connected to the ship model 1; the stepper motor 2-1 is fixedly connected to the ship model 1 and connected to the first transmission device, wherein the first transmission device is connected to the slider 2-2, and is used to drive the slider 2-2 to make lateral movements on the ship model 1. The first transmission device includes a belt 2-4, a pulley 2-5 and a guide wheel 2-6, wherein the pulley 2-5 and the guide wheel 2-6 are respectively hinged to the ship model 1, the belt 2-4 is wound around the pulley 2-5 and the guide wheel 2-6, the stepper motor 2-1 is driven and connected to the pulley 2-5, and the slider 2-2 is fixedly connected to the belt 2-4.

[0032] In this embodiment, the forced roll device 2 also includes a base 2-7, which is fixed on the ship model 1, and a stepper motor 2-1 is fixed to the bottom of the base 2-7. The rotating shaft of the stepper motor 2-1 is fixedly connected to the pulley 2-5; two guide wheels 2-6 are respectively installed on the left and right sides of the base 2-7 through cylindrical pins and can rotate freely; there are a total of four guide wheels 2-6, and the belt 2-4 is sleeved on the outer ring of the triangle formed by the pulley 2-5 and the two guide wheels 2-6, and contacts the outer ring of the belt 2-4 through another two guide wheels 2-6 installed on the base 2-7, which plays a role in tensioning the belt 2-4; the slide rail 2-3 is installed above the base 2-7, and the slider 2-2 is nested on the slide rail 2-3 and can slide left and right. The slider 2-2 is fixedly connected to the belt 2-4 at one point by bolts; the rotation of the stepper motor 2-1 can be converted into the translational motion of the slider 2-2, and the translational motion of the slider 2-2 is used to realize the forced roll motion of the ship model 1.

[0033] The sensor device includes an accelerometer 5 and a gyroscope 4. The accelerometer 5 is placed on the port side or starboard side of the deck to measure the roll acceleration at that position; the gyroscope 4 is placed on the longitudinal section of the ship model 1 to monitor the ship's roll angle, roll angular velocity and other information.

[0034] like Figure 3 As shown, the fin anti-roll device 3 is provided with two sets, and the fin anti-roll device 3 includes a fin drive motor 3-1, a second transmission device and a flapping fin 3-6. Among them, the second transmission device includes a connecting shaft 3-2, a waterproof sleeve 3-3, a gear box base 3-4, and a right-angle gear box 3-5.

[0035] Two fin drive motors 3-1 are fixedly connected to the left and right sides of the ship, and the drive shafts of the fin drive motors 3-1 are in the vertical direction; two right-angle gear boxes 3-5 are respectively installed on both sides of the gear box base 3-4 of the outer groove of the middle section of the ship model 1, and are located directly below the fin drive motor 3-1; the vertical axis of the right-angle gear box 3-5 is connected to the drive shaft of the fin drive motor 3-1 through the connecting shaft 3-2, and the connecting shaft 3-2 passes through the inside and outside of the hull through the waterproof shaft sleeve 3-3; the rotation axis of the flapping fin 3-6 is fixedly connected to the horizontal axis of the right-angle gear box 3-5. The rotation of the rotating shaft of the fin drive motor 3-1 can be converted into the flapping of the flapping fin 3-6.

[0036] like Figure 4 As shown, a control method of a test device for reducing rolling at zero speed of a ship comprises the following steps: The forced rolling device 2 drives the ship model 1 to produce a rolling motion; The gyroscope 4 and accelerometer 5 monitor the ship's attitude information, including key information such as roll angle, roll angular velocity and acceleration, and convert this information into state signals and input them into the PPO algorithm agent; Based on the received ship motion posture information and the actual environment status, the PPO algorithm agent generates the flapping angle and action decision of the fin anti-roll device 3 through the strategy network. At this time, the PPO algorithm determines the optimal motion angle of the fin anti-roll device 3 through its strategy function to maximize the anti-roll effect.

[0037] The diving servo drives the diving servo to rotate according to the angle signal of the fin anti-roll device 3 output by the PPO algorithm agent, and makes the flapping of the flapping fins 3-6 reach the specified angle and frequency.

[0038] After the flapping fin 3-6 moves, the gyroscope 4 monitors the attitude change of the ship (the reduction of the ship's roll angle) and the actual flapping angle of the flapping fin 3-6 in real time, and returns the feedback signal to the PPO algorithm agent. The PPO algorithm agent evaluates the effectiveness of the current strategy through the reward mechanism in the evaluation function of reinforcement learning: if the anti-roll effect is ideal, the agent strengthens the current strategy; if the effect is not good, the PPO algorithm agent further optimizes the control action of the flapping fin 3-6 by updating the strategy network.

[0039] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A test device for reducing rolling at zero speed of a ship, characterized in that: It comprises a ship model and a control device, wherein a forced rolling device, a sensor device and a fin anti-rolling device are installed on the ship model; The forced rolling device is used to drive the ship model to produce rolling motion; The sensor device is used to monitor the attitude information of the ship model during the rolling motion, including the rolling angle, the rolling angular velocity and the rolling acceleration, and send the information to the control device; The control device is used to generate an action decision of the fin anti-roll device through a strategy network according to the received ship model attitude information; The fin stabilization device flaps to the specified angle and frequency according to the action decision generated by the control device; The sensor device monitors the changes in the ship model's posture and the actual flapping angle of the fin anti-roll device in real time and feeds back to the control device. The control device evaluates the effectiveness of the current strategy based on the feedback from the sensor device: if the anti-roll effect meets the requirements, the current strategy is strengthened; otherwise, the strategy network is updated to further optimize the control action of the fin anti-roll device.

2. The test device according to claim 1, characterized in that: The forced roll device includes a stepper motor, a first transmission device and a slider, wherein the slider is slidably connected to the ship model; the stepper motor is fixed to the ship model and connected to the first transmission device, and the first transmission device is connected to the slider, so as to drive the slider to move laterally on the ship model.

3. The test device according to claim 1, characterized in that: The first transmission device comprises a belt, a pulley and a guide wheel. The pulley and the guide wheel are respectively hinged to the ship model. The belt is wound around the pulley and the guide wheel. The stepper motor is driven and connected to the pulley. The slider is fixed to the belt.

4. The test device according to claim 3, characterized in that: The first transmission device also includes a slide rail, which is fixed to the ship model, and the sliding block is nested on the slide rail and slidably connected to the slide rail.

5. The test device according to claim 1, characterized in that: The sensor device comprises an accelerometer and a gyroscope. The accelerometer is arranged on the side of the ship model for measuring the roll acceleration of the ship model; the gyroscope is arranged at the middle longitudinal section of the ship model for measuring the roll angle and roll angular velocity of the ship model.

6. The test device according to claim 1, characterized in that: The fin anti-roll device comprises a fin drive motor, a second transmission device and a flapping fin. The fin drive motor is fixed to the ship model and connected to the second transmission device. The second transmission device is connected to the flapping fin and is used to drive the flapping fin to flap repeatedly.

7. The test device according to claim 6, characterized in that: The second transmission device includes a right-angle gearbox, the driving shaft of the fin drive motor is vertically arranged, the right-angle gearbox is located below the fin drive motor, the right-angle gearbox includes a linked vertical axis and a horizontal axis, the vertical axis of the right-angle gearbox is connected to the driving shaft of the fin drive motor, and the flapping fins are connected to the horizontal axis of the right-angle gearbox.

8. The test device according to claim 1, characterized in that: There are two sets of fin anti-roll devices, which are respectively arranged on the left and right sides of the ship model.

9. The test device according to claim 1, characterized in that: The control device is a PPO algorithm agent.

10. The control method of the test device for reducing the rolling of a ship at zero speed according to any one of claims 1 to 9, characterized in that: The following steps are included: The forced rolling device drives the ship model to produce rolling motion; The sensor device monitors the attitude information of the ship model during the rolling motion, including the rolling angle, the rolling angular velocity and the rolling acceleration, and sends the information to the control device; The control device generates an action decision of the fin anti-roll device through a strategy network according to the received ship model attitude information; The fin stabilization device flaps to the specified angle and frequency according to the action decision generated by the control device; The sensor device monitors the changes in the ship model's posture and the actual flapping angle of the fin anti-roll device in real time and feeds back to the control device. The control device evaluates the effectiveness of the current strategy based on the feedback from the sensor device: if the anti-roll effect meets the requirements, the current strategy is strengthened; otherwise, the strategy network is updated to further optimize the control action of the fin anti-roll device.

Images