An adjustable attack angle electric control type boat water wing and control system

Abstract

This invention discloses an adjustable angle-of-attack electrically controlled hydrofoil and control system for a submarine, relating to the field of angle-of-attack control technology. It addresses the risk of bottom contact during navigation in shallow water due to insufficient bottom clearance and limited lift compensation. The system includes a condition determination module, a thrust-back fitting module, a risk level determination module, and an angle-of-attack execution module, all interconnected. The condition determination module acquires water depth, draft, and height above water using sensors, calculates the bottom clearance, and compares it with the minimum safe clearance to determine if a shallow water condition has been triggered. The thrust-back fitting module calculates the actual lift based on the submarine's weight, buoyancy, and vertical acceleration when the shallow water condition is triggered, and fits a shallow water correction lift slope. The risk level determination module calculates the remaining available lift and the lift required for lifting, setting a risk flag using a dual-condition criterion. The angle-of-attack execution module adjusts the angle of attack based on the risk flag, achieving closed-loop control.

Description

Technical Field

[0001] This invention relates to the field of angle-of-attack control technology, and more specifically, to an electrically controlled hydrofoil and control system for an adjustable angle-of-attack submarine. Background Technology

[0002] Hydrofoils use the lift generated by their hydrofoils as they navigate through water to lift the hull above the surface, effectively reducing drag and significantly improving speed and seaworthiness. However, when a hydrofoil enters shallow water, its operating environment changes dramatically. The gap between the hydrofoil and the seabed narrows drastically, causing complex shallow-water effects. These effects alter the flow field characteristics passing through the hydrofoil, leading to nonlinear changes in its lift characteristics, typically manifested as an increase in lift slope at the same angle of attack.

[0003] This change in physical characteristics poses a serious challenge to the navigation safety of hydrofoils. On the one hand, it is difficult for operators to accurately perceive and predict this dynamically changing lift based on experience; on the other hand, traditional fixed control logic or purely manual operation modes cannot respond quickly and accurately. Existing technologies often lack accurate monitoring and risk assessment of real-time bottom clearance in shallow water conditions, and even more so, they lack a control mechanism that can adapt to changes in lift and proactively intervene for safety. This makes hydrofoils highly susceptible to insufficient or untimely lift compensation when navigating in shallow water, resulting in insufficient hull lift and a risk of bottom contact with the seabed or underwater obstacles, seriously threatening navigation safety and the hull structure.

[0004] Therefore, there is an urgent need in the field for a control system that can intelligently sense shallow water environments, assess the risk of bottoming out in real time, and automatically adjust the hydrofoil angle of attack to provide sufficient and safe lift. In response to the above problems, this invention proposes a solution. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention provide an adjustable angle-of-attack electronically controlled hydrofoil and control system for hydrofoils, which solves the problem of potential bottoming out when hydrofoils are navigating in shallow water due to insufficient distance to the seabed and limited lift compensation capability of the hydrofoils.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An adjustable angle-of-attack electrically controlled submarine hydrofoil and control system includes: a working condition determination module, a push fitting module, a risk level determination module, and an angle-of-attack execution module, with signal connections between the modules;

[0008] Working condition determination module: It obtains water depth, draft and height above water value through sensors, calculates bottom clearance using basic model and modified model, and compares the calculated bottom clearance with the set minimum safe clearance to determine whether shallow water working condition is triggered.

[0009] Back-fitting module: When triggered in shallow water conditions, the actual lift is calculated based on the force balance equation by combining the weight, buoyancy and vertical acceleration of the vessel. The shallow water corrected lift slope is calculated using the least squares method and compared with the product of the decision coefficient and the standard lift slope to select the corresponding lift slope.

[0010] Risk level determination module: Calculates the remaining available lift force by combining the lift slope, and calculates the lift force required for lifting based on the hull weight and lift ratio coefficient. Determines the risk level through dual-condition criteria, and sets risk flags including high-risk state, controllable state and no-risk state according to the condition.

[0011] Angle of attack execution module: When calculating the target angle of attack risk based on the risk flag, it increases the angle of attack within the allowable angle of attack range according to the upper limit of the adjustment rate. When it is under controllable conditions, it adjusts or maintains the angle of attack at a small rate. When it is not triggered, it maintains the status quo, converts the target angle of attack into a control signal for the actuator, and corrects the actual angle of attack in a closed loop.

[0012] In a preferred embodiment, the operating condition determination module includes the following steps:

[0013] Obtain water depth, draft, and height above water;

[0014] The bottom clearance is calculated based on the water depth, draft, and height above the water.

[0015] Set a safe minimum clearance, which is determined based on the draft and speed values;

[0016] The bottom clearance and the minimum safe clearance are compared to set the shallow water condition flag, where the shallow water condition flag indicates that the shallow water condition is triggered when the bottom clearance is less than the minimum safe clearance.

[0017] In a preferred embodiment, the backfit module includes the following steps:

[0018] When the shallow water condition flag indicates that the shallow water condition has been triggered, obtain the vertical acceleration, speed, actual angle of attack, ship mass, and buoyancy coefficient per unit draft.

[0019] The actual lift is calculated based on vertical acceleration, shipboard mass, buoyancy coefficient per unit draft, and draft value. The formula for calculating the actual lift is as follows: Where m is the ship's mass and g is the acceleration due to gravity. For buoyancy, It is the vertical acceleration;

[0020] Calculate the ship's onboard mass, which includes the hull's empty mass, current load mass, and fuel consumption mass.

[0021] Buoyancy is calculated based on the draft and the buoyancy coefficient per unit draft, where the buoyancy calculation formula is: ;in, The buoyancy coefficient per unit draft is calculated by integrating the cross-sectional area of ​​the underwater portion of the hull to obtain the displacement volume per unit draft. Then multiply by the density of water ρ and the gravitational acceleration g, that is ;

[0022] Calculate the shallow water corrected lift slope and use the least squares method to fit the relationship between the actual angle of attack and the actual lift.

[0023] Compare the shallow water corrected lift slope with the standard lift slope. If the shallow water corrected lift slope is greater than a predetermined multiple of the standard lift slope, the shallow water corrected lift slope is used as the lift slope; otherwise, the standard lift slope is used as the lift slope.

[0024] In a preferred embodiment, the risk level determination module includes the following steps:

[0025] The remaining available lift is calculated based on the accelerability angle and lift slope, where the formula for calculating the remaining available lift is: ,in, The lift slope currently being used is the one determined in step S2. or ;

[0026] The required lifting force is calculated based on the ship's mass and the lifting ratio coefficient. The formula for calculating the required lifting force is as follows: Where λ is the lifting ratio coefficient;

[0027] Based on the comparison between the bottom clearance and the minimum safe clearance, as well as the comparison between the remaining available lifting force and the lifting force required for lifting, a bottoming risk indicator is set;

[0028] When the bottom clearance is less than the minimum safe clearance and the remaining available lifting force is less than the lifting force required for lifting, the bottoming risk indicator shows a high-risk state.

[0029] When the bottom clearance is less than the minimum safe clearance but the remaining available lifting force is greater than or equal to the lifting force required for lifting, the bottoming risk indicator shows a controllable state.

[0030] In a preferred embodiment, the angle of attack execution module includes the following steps:

[0031] Calculate the target angle of attack based on the bottoming risk indicator;

[0032] When the bottoming-out risk indicator shows a high-risk state, the angle of attack is increased at the maximum adjustment rate;

[0033] When the bottom risk indicator shows a controllable state, the angle of attack is increased at a slightly adjusted rate.

[0034] Calculating the angle of attack target: In a high-risk situation, the formula for calculating the angle of attack target is as follows: ;in, The maximum allowable angle of attack adjustment for this control cycle is expressed as: ;in, To adjust the upper limit of the rate, To control the cycle;

[0035] When under controllable conditions, the formula for calculating the angle of attack target is: ;in, Based on the small adjustment rate and control period determination ;

[0036] The angle of attack of the hydrofoil is adjusted by PWM signal, and a closed-loop position control is formed based on the feedback of the actual angle of attack.

[0037] The technical effects and advantages of the adjustable angle-of-attack electronically controlled submarine hydrofoil and control system of the present invention are as follows:

[0038] By adjusting the hydrofoil's angle of attack to generate additional lift, the hull is actively raised, fundamentally avoiding the possibility of collision with the seabed and significantly enhancing safety in complex shallow waters. A thrust-back fitting module is introduced, which dynamically fits the current hydrofoil's lift slope in shallow water conditions using real-time data. This accurately captures and adapts to changes in lift characteristics caused by shallow water effects, ensuring that subsequent risk assessments and angle-of-attack adjustments are based on a realistic and reliable physical foundation, greatly improving the accuracy and environmental adaptability of the entire control system. The risk of bottoming out is quantified and graded. For different risk levels, the angle-of-attack module employs differentiated adjustment strategies: rapid response and maximum lift enhancement in high-risk situations; and small, fine adjustments in controllable conditions. This hierarchical control logic ensures maximum risk avoidance in critical situations while preventing drastic hull attitude fluctuations caused by sudden changes in angle of attack under normal risk conditions, guaranteeing navigational stability and crew comfort. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of an electrically controlled hydrofoil and control system module for an adjustable angle-of-attack boat according to the present invention.

[0040] Figure 2 This is a schematic diagram of the adjustable angle-of-attack electric-controlled submarine hydrofoil and control system according to the present invention. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Example

[0043] Please see Figures 1-2 As shown, the present invention discloses an adjustable angle-of-attack electronically controlled submarine hydrofoil and control system, including: a working condition determination module, a push fitting module, a risk level determination module, and an angle-of-attack execution module, with signal connections between the modules;

[0044] Working condition determination module: It obtains water depth, draft and height above water value through sensors, calculates bottom clearance using basic model and modified model, and compares the calculated bottom clearance with the set minimum safe clearance to determine whether shallow water working condition is triggered.

[0045] Back-fitting module: When triggered in shallow water conditions, the actual lift is calculated based on the force balance equation by combining the weight, buoyancy and vertical acceleration of the vessel. The shallow water corrected lift slope is calculated using the least squares method and compared with the product of the decision coefficient and the standard lift slope to select the corresponding lift slope.

[0046] Risk level determination module: Calculates the remaining available lift force by combining the lift slope, and calculates the lift force required for lifting based on the hull weight and lift ratio coefficient. Determines the risk level through dual-condition criteria, and sets risk flags including high-risk state, controllable state and no-risk state according to the condition.

[0047] Angle of attack execution module: When calculating the target angle of attack risk based on the risk flag, it increases the angle of attack within the allowable angle of attack range according to the upper limit of the adjustment rate. When it is under controllable conditions, it adjusts or maintains the angle of attack at a small rate. When it is not triggered, it maintains the status quo, converts the target angle of attack into a control signal for the actuator, and corrects the actual angle of attack in a closed loop.

[0048] In the working condition determination module, water depth, draft, and height above water are acquired through sensors. The bottom clearance is calculated using a basic model and a modified model, and a minimum safe clearance is set for comparison to determine whether a shallow water working condition has been triggered. Specific details include:

[0049] Water depth values ​​are obtained from ultrasonic depth sounders. The sensor needs to cover the set measurement range and meet the specified measurement accuracy; the draft value is obtained from the hydrostatic draft sensor. The sensor must cover the set measurement range and meet the specified measurement accuracy; the water height value is obtained from the laser water height sensor, which must cover the set measurement range and meet the specified measurement accuracy.

[0050] Bottom gap The calculation is divided into two scenarios depending on whether a correction for the height above the water is introduced. Both scenarios are derived based on the geometric relationship between the vertical distance from the bottom edge of the hull to the water surface and the vertical distance from the water surface to the bottom:

[0051] Basic calculation model: When no additional correction for the hull's floating state is required, the bottom clearance is determined solely by the water depth. With draft The decision, among which, is based on water depth. The vertical distance from the bottom to the water surface measured by the sensor; draft. The waterline is the vertical distance from the waterline to the bottom edge of the hull. Therefore, the formula for calculating the bottom clearance is: ;

[0052] Corrected calculation model: When there is a geometric deviation between the water height sensor installed on the hull and the actual force reference plane of the hull, a water height correction amount needs to be introduced. For a known fixed value, it is determined by measuring with a laser rangefinder during initial installation and commissioning. The measurement method involves placing the hull in a horizontal dry dock and measuring the vertical distance from the center of the water level sensor probe to the actual force reference plane. If the sensor probe is higher than the reference plane, the water level correction is positive; otherwise, it is negative. The bottom clearance is then calculated as follows: ;in, The initial setting for the height correction above the water is 0.1m, meaning the sensor probe is 0.1m above the force reference plane.

[0053] Minimum safety clearance This is the threshold for determining shallow water conditions, used to characterize the minimum safe distance the hull must maintain on the seabed in the current water area. Its setting needs to comprehensively consider three major factors:

[0054] Impact of hull draft: The greater the hull draft, the smaller the safety margin between the bottom and the seabed, and the greater the minimum safety clearance needs to be.

[0055] Impact of speed: The higher the speed, the greater the longitudinal response delay of the hull, and the more obvious the disturbance of the bottom caused by the waves generated by the hull at high speeds, the greater the minimum safe clearance needs to be.

[0056] Expected wave height safety reserve: Wave heights in shallow water are usually smaller, so it is necessary to reserve clearance redundancy during wave troughs to avoid a sudden drop in bottom clearance due to instantaneous wave troughs.

[0057] The minimum safe clearance is determined using a segmented method. The hull draft is divided into several draft segments, and the speed is divided into several speed segments. The critical clearance for bottoming is obtained in tank tests for each draft segment × speed segment and then fixed as the minimum safe clearance for that combination. The fixed minimum safe clearance is taken out according to the current hull draft and speed positioning corresponding segments. If a safety reserve for wave height is required, the value is determined by adding the fixed value of each segment to the safety reserve for wave height based on the combination of hull draft and speed.

[0058] The decision-making logic is based on a comparison between the bottom clearance and the minimum safe clearance, with the following criteria:

[0059] Shallow water condition marker This is a Boolean variable used to indicate whether the shallow water condition has been triggered. The decision logic is based on the bottom clearance. With minimum safety clearance The comparison is based on the following criteria:

[0060] when When the shallow water condition is not triggered, the setting is... =0;

[0061] when When the condition is determined to be shallow water, the setting is initiated. =1, proceed to step S2 for the lift reverse thrust process.

[0062] In the back-fitting module, when the shallow water condition is triggered, the actual lift is calculated based on the force balance equation by combining the vessel's weight, buoyancy, and vertical acceleration. The shallow water corrected lift slope is calculated using the least squares method, and compared with the product of the decision coefficient and the standard lift slope to select the corresponding lift slope. Specific details include:

[0063] Shallow water condition triggering When =1, except for the draft value in step S1. In addition, it is also necessary to obtain vertical acceleration, speed, actual angle of attack, shipboard mass, and buoyancy coefficient per unit draft;

[0064] The actual lift calculation is as follows: the forces in the vertical direction include: upward hydrofoil lift. The downward force of the boat's weight G and the upward buoyancy force According to Newton's second law The force equilibrium equation in the vertical direction is: After sorting, the formula for calculating the actual lift is obtained: Where m is the ship's mass, and g is the gravitational acceleration, taken as the standard value g = 9.81 m / s². For buoyancy, It is the vertical acceleration;

[0065] The ship's onboard mass *m* is the sum of the ship's empty mass and the current load mass, and it is corrected in real time according to the fuel level. The specific calculation method is as follows: ;in, For shipborne empty weight, For the current load mass, The remaining fuel mass is calculated by measuring the product of the current fuel volume and fuel density using a fuel level sensor. This remaining fuel mass is then subtracted from the initial fuel mass. If fuel consumption is negligible, such as for short-duration navigation in shallow waters, a setting can be made. =0;

[0066] buoyancy The draft is determined by the weight of the water displaced by the hull. Buoyancy coefficient per unit draft The calculation, expressed by the formula, is as follows: ;in, The buoyancy coefficient per unit draft represents the corresponding increase in buoyancy. It is calculated by integrating the cross-sectional distribution of the underwater portion of the hull to obtain the displacement volume per unit draft. Then multiply by the density of water ρ and g, that is ;

[0067] Vertical acceleration The raw data acquired by the IMU contains high-frequency noise and requires a fixed-time moving average filter. The filter window length is set to 0.1s, and the filter formula is as follows: ;in, Here, represents the filtered vertical acceleration, and n is the number of samples in the sliding window. The raw vertical acceleration acquired during the j-th control cycle;

[0068] Substituting the above parameters into the actual lift formula, and applying the same moving average filter as the vertical acceleration to the calculation results, a smooth actual lift sequence is obtained. ;

[0069] Shallow water corrected lift slope This represents the increase in lift corresponding to a unit angle change under shallow water conditions. The fitting process requires three steps: data collection and validity assessment, least squares fitting, and comparison with the standard lift slope.

[0070] The data collection time window is set to cover a sufficient control period, ensure fitting accuracy, and reflect the real-time changes in the lift slope. This is triggered when the shallow water condition flag is activated. Once triggered, it continuously collects multiple sets of data including actual angle of attack, actual lift, and speed values;

[0071] Only when the speed value The minimum value greater than the hydrofoil's lift operating speed At that time, the minimum operating speed of the hydrofoil lift is determined by the hydrofoil design parameters. If the speed value does not meet this condition, it means that the hydrofoil lift is insufficient, the data is invalid, and no subsequent shallow water correction is performed.

[0072] The least squares fitting steps are as follows:

[0073] Assuming the actual angle of attack With actual lift A linear relationship is satisfied, which can be expressed as: ;in, To correct the lift slope in shallow water, The fitting intercept has no actual physical meaning and is only used for fitting calculations;

[0074] Based on the least squares method, to minimize the sum of squared residuals between the fitted values ​​and the actual values, the following is derived: The calculation is expressed as: Where n is the number of valid data sets participating in the fitting. Let i be the actual angle of attack of the i-th data set. The actual lift of the i-th data set;

[0075] Standard lift slope The lift slope of the hydrofoil under deep-water conditions was determined through pool tests and set to 10000 N / °. The comparison criterion was:

[0076] like When the shallow water corrected lift slope is greater than 1.1 times the standard lift slope, it indicates that the hydrofoil can achieve higher lift at the same angle of attack due to the bottom effect, and thus the shallow water corrected lift slope should be used. As the lift slope for subsequent calculations;

[0077] like When the shallow water corrected lift slope is less than or equal to 1.1 times the standard lift slope, it indicates that the bottom effect is not significant and the standard lift slope is maintained. As the lift slope for subsequent calculations;

[0078] It should be noted that 1.1 is the determination coefficient. Based on multiple shallow water pool tests, the bottom effect, i.e., the constraint effect of shallow water on the water flow, causes the lift slope to increase by up to 10%. Therefore, 1.1 is taken as the determination coefficient.

[0079] In the risk level determination module, the remaining available lift force is calculated based on the lift slope, and the required lift force for lifting is calculated based on the hull weight and lift ratio coefficient. The risk level is determined through a dual-condition criterion, and risk flags are set according to the condition being met, including high-risk, controllable, and risk-free states. Specific content includes:

[0080] Remaining available lift This represents the maximum additional lift that can be obtained by increasing the angle of attack in the current shallow water environment. The calculation requires first determining the angle that can be increased, and then deriving it by combining the lift slope, as detailed below:

[0081] Increase angle This represents the difference between the upper limit of the allowable angle of attack of the angle-of-attack actuator and the current actual angle of attack, reflecting the adjustable margin of the angle of attack. The formula is as follows: ;in, The upper limit of the permissible angle of attack is determined jointly by the hydrofoil's stall characteristics and the actuator stroke. The stall angle of attack for a hydrofoil is typically 12°-15°. To avoid a sudden drop in lift due to stall, a safety margin of 2°-3° is reserved, which can be set as follows: =10°, This is the current actual angle of attack;

[0082] It should be noted that when If this occurs, it indicates that the angle of attack has exceeded the permissible limit, or that there is a malfunction in the actuator. In this case, the setting should be... This means that lift can no longer be obtained by increasing the angle of attack;

[0083] The remaining available lift is the product of the increase angle and the lift slope, expressed as: ;in, The lift slope currently being used is the one determined in step S2. or ;

[0084] Lifting force required This indicates that the bottom edge of the hull has returned to the safe minimum clearance. The required lift increment is calculated using a fixed percentage method, i.e., set as a certain percentage of the hull's weight, specifically 10%-20%. The lift increment required to lift the hull is directly related to its weight. Tank tests have verified that when the lift increment is 10%-20% of the hull's weight, the hull can be lifted by 0.1m-0.3m within 0.5s-1s, which is sufficient to raise the bottom clearance from below [a certain value]. Return to a safe value. The specific ratio needs to be adjusted according to the weight of the hull: when the hull weight is small, i.e., m < 10000 kg, the lifting ratio coefficient is 10%-15%, and the lifting force required is small; when the hull weight is large, i.e., m ≥ 10000 kg, the lifting ratio coefficient is 15%-20%, and a larger lift force is required to lift.

[0085] The weight of the hull is the product of the ship's mass and gravitational acceleration. The lift required for lifting is calculated as follows: Where λ is the lifting ratio coefficient;

[0086] The risk level of hitting bottom is determined by a two-condition criterion, which is defined and defined as follows:

[0087] Condition 1: Bottom clearance This means that shallow water conditions have been triggered. ;

[0088] Condition 2: Remaining available lift This means that the lift compensation capability is insufficient, and it is impossible to raise the hull to a safe clearance by increasing the angle of attack.

[0089] The risk level classification and flag settings are as follows:

[0090] Set the bottoming risk flag only if both conditions one and two are met. The current operating condition is marked as a high-risk bottoming-out state;

[0091] When condition one is met but condition two is not, a bottoming-out risk flag is set. 1. If the current bottom clearance is insufficient but sufficient lift can still be obtained by increasing the angle of attack, mark the current working condition as a controllable bottoming state and set the bottoming risk flag to the corresponding state.

[0092] If condition one is not met, set a bottoming-out risk flag. The current working condition is marked as a risk-free state, and the bottoming-out risk flag is set to the corresponding state. In this case, the process does not proceed to step S4.

[0093] In the angle-of-attack execution module, when calculating the target angle-of-attack risk based on the risk flag, the adjustment rate is increased within the allowable angle-of-attack range at the upper limit. When under controllable conditions, the rate is adjusted or maintained at a small increment. When not triggered, the status quo is maintained. The target angle of attack is converted into a control signal for the actuator and the actual angle of attack is corrected in a closed loop. Specific details include:

[0094] The calculation logic for the angle of attack target follows the bottoming risk flag. The core principle of change is to rapidly increase the angle of attack when the risk is high, and to smoothly adjust the angle of attack when the risk is controllable.

[0095] When the risk of hitting rock bottom is determined, the angle of attack must be increased as quickly as possible within the mechanical limits. The formula for calculating the target angle of attack is: ;in, The maximum allowable angle of attack adjustment during this control cycle is determined by the upper limit of the adjustment rate and the control cycle, and is expressed as: ;in, The upper limit of the adjustable speed is determined by the motor power and reduction ratio. The electronically controlled actuator has an adjustable speed limit of 2° / s. This speed can increase the angle of attack from 7° to 8° within 0.5s, which can meet the requirements for rapid lifting. The control cycle can be set to 0.1s;

[0096] like Then Cut off as To avoid exceeding the actuator's travel range or hydrofoil stall;

[0097] When it is determined that the bottom has been reached and is under control, i.e., the bottom risk indicator is reached. 1. There is no need to rapidly increase the angle of attack; simply maintain the current angle of attack or adjust it slightly upwards to avoid excessive pitching of the hull due to a sudden increase in angle of attack. Excessive pitching will reduce the longitudinal stability of the hull. The specific logic is as follows: Set an upper limit for the rate of small adjustments. This rate allows the angle of attack to increase by only 0.5° within 1 second, resulting in a smooth nose-up without significant turbulence. Therefore, the upward adjustment for this cycle... The target of attack is ;

[0098] If no further lifting is needed, meaning the bottom clearance is close to a safe value, it can be set... ,Right now ;

[0099] Angle of attack target After generation, the electronic control processing unit adjusts the hydrofoil's angle of attack via PWM signals and uses a potentiometer to control the actual angle of attack. Real-time feedback forms a closed-loop position control.

[0100] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0101] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0102] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and inventive constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0103] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0104] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0105] In conclusion, the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A control system for an electrically controlled variable angle of attack hydrofoil for a boat, characterized in that, Signal connections between modules; Working condition determination module: It obtains water depth, draft and height above water value through sensors, calculates bottom clearance using basic model and modified model, and compares the calculated bottom clearance with the set minimum safe clearance to determine whether shallow water working condition is triggered. Back-fitting module: When triggered in shallow water conditions, the actual lift is calculated based on the force balance equation by combining the weight, buoyancy and vertical acceleration of the vessel. The shallow water corrected lift slope is calculated using the least squares method and compared with the product of the determination coefficient and the standard lift slope to select the corresponding lift slope. Risk Level Determination Module: This module calculates the remaining available lift force based on the lift slope and the required lift force for lifting based on the hull weight and lift ratio coefficient. It determines the risk level using a dual-condition criterion and sets risk flags (high-risk, controllable, and risk-free) according to the conditions met. Specifically, the remaining available lift force is calculated based on the accelerable angle and lift slope. The formula for calculating the remaining available lift force is as follows: ,in, The current lift slope is used; the required lift force is calculated based on the ship's mass and lift ratio coefficient, where the formula for calculating the required lift force is: Where λ is the lift ratio coefficient, m is the ship's mass, and g is the gravitational acceleration. Angle of attack execution module: When calculating the target angle of attack risk based on the risk flag, the angle of attack is increased within the allowable angle of attack range at the upper limit of the adjustment rate. When under controllable conditions, the angle of attack is adjusted or maintained at a small rate. When not triggered, the current state is maintained. The target angle of attack is converted into a control signal for the actuator and the actual angle of attack is corrected in a closed loop. Specifically, the target angle of attack is calculated based on the bottom-out risk flag. When the bottom-out risk flag indicates a high-risk state, the angle of attack is increased at the maximum adjustment rate. When the bottom-out risk flag indicates a controllable state, the angle of attack is increased at a small adjustment rate. The target angle of attack is calculated. When in a high-risk state, the formula for calculating the target angle of attack is: ;in, The maximum allowable angle of attack adjustment for this control cycle is expressed as: ;in, To adjust the upper limit of the rate, To control the cycle; when in a controllable state, the formula for calculating the angle of attack target is: ;in, Based on the small adjustment rate and control period determination The angle of attack of the hydrofoil is adjusted by PWM signal, and a position closed-loop control is formed based on the feedback of the actual angle of attack.

2. The control system for an adjustable angle-of-attack electrically controlled hydrofoil of a submarine according to claim 1, characterized in that, Obtain water depth, draft, and height above water; The bottom clearance is calculated based on the water depth, draft, and height above the water.

3. A control system for an adjustable angle-of-attack electrically controlled hydrofoil for a submarine, as described in claim 2, is characterized in that... Set a safe minimum clearance, which is determined based on the draft and speed values; The bottom clearance and the minimum safe clearance are compared to set the shallow water condition flag, where the shallow water condition flag indicates that the shallow water condition is triggered when the bottom clearance is less than the minimum safe clearance.

4. A control system for an electrically controlled, angle-of-attack submarine hydrofoil according to claim 1, characterized in that, When the shallow water condition flag indicates that the shallow water condition has been triggered, obtain the vertical acceleration, speed, actual angle of attack, ship mass, and buoyancy coefficient per unit draft. The actual lift is calculated based on vertical acceleration, shipboard mass, buoyancy coefficient per unit draft, and draft value. The formula for calculating the actual lift is as follows: Where m is the ship's mass and g is the acceleration due to gravity. For buoyancy, This is the vertical acceleration.

5. A control system for an electrically controlled, angle-of-attack submarine hydrofoil according to claim 4, characterized in that, Calculate the ship's onboard mass, which includes the hull's empty mass, current load mass, and fuel consumption mass. Buoyancy is calculated based on the draft and the buoyancy coefficient per unit draft, where the buoyancy calculation formula is: ;in, The buoyancy coefficient per unit draft is calculated by integrating the cross-sectional area of ​​the underwater portion of the hull to obtain the displacement volume per unit draft. Then multiply by the density of water ρ and the gravitational acceleration g, that is .

6. A control system for an adjustable angle-of-attack electrically controlled submarine hydrofoil according to claim 4, characterized in that, Calculate the shallow water corrected lift slope and use the least squares method to fit the relationship between the actual angle of attack and the actual lift. Compare the shallow water corrected lift slope with the standard lift slope. If the shallow water corrected lift slope is greater than a predetermined multiple of the standard lift slope, the shallow water corrected lift slope is used as the lift slope; otherwise, the standard lift slope is used as the lift slope.

7. A control system for an adjustable angle-of-attack electrically controlled hydrofoil for a submarine, as described in claim 1, is characterized in that... Based on the comparison between the bottom clearance and the minimum safe clearance, as well as the comparison between the remaining available lifting force and the lifting force required for lifting, a bottoming risk indicator is set; When the bottom clearance is less than the minimum safe clearance and the remaining available lifting force is less than the lifting force required for lifting, the bottoming risk indicator shows a high-risk state. When the bottom clearance is less than the minimum safe clearance but the remaining available lifting force is greater than or equal to the lifting force required for lifting, the bottoming risk indicator shows a controllable state.

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