Method for optimizing distribution of thrust in layers for twin waterjet propulsors

Abstract

A kind of double water jet propeller thrust layering optimization distribution method, the mechanical model of double water jet propeller of unmanned ship of configuration foundation is divided into regions and vector synthesis method, first layer thrust distribution optimization model is obtained and is solved to obtain partial thrust vector, complete first distribution;Second distribution is carried out under the equation restriction condition between adding reverse bucket and thrust by minimum distance method, the reverse bucket angle of double propeller and corresponding main engine power are obtained;Finally when singularity phenomenon occurs in second layer distribution, do not intervene in thrust distribution process, directly control jet flow velocity alone, so as to realize thrust optimization.The invention simultaneously considers propeller angle rotation rate limit, reverse bucket rotation rate limit and the influence of reverse bucket on thrust, and optimizes control accuracy and control principle;By more accurate control of reverse bucket, the reverse bucket is included in the control of thrust, the convergence time when the propeller gets negative force is shortened, and the main engine power oscillation amplitude can be controlled in the process of propeller thrust size floating, reducing propeller shaft wear.

Description

TECHNICAL FIELD

[0001] The application relates to the field of unmanned ships, and particularly relates to a double-water-jet-propeller thrust layering optimization distribution method considering reverse force of a reverse bucket. BACKGROUND

[0002] The existing water-jet-propeller and thrust distribution have the following problems: first, the discontinuous thrust range causes the thrust range to be non-convex; and second, the reverse bucket has a non-linear equal constraint relationship with the thrust, so that the limitation condition is non-convex. SUMMARY

[0003] The application discloses a double-water-jet-propeller thrust layering optimization distribution method, which is proposed in view of the problem that the existing thrust distribution technology is not suitable for the double-water-jet-propelling mode and cannot control the negative force of the reverse bucket. The method applies the layering optimization idea, simultaneously considers the propeller angle rotation rate limitation, the reverse bucket rotation rate limitation and the influence of the reverse bucket on the thrust, and optimizes the control precision and the control principle. Through more accurate control of the reverse bucket, the reverse bucket is integrated into the thrust control, the convergence time when the propeller obtains the negative force is shortened, the main engine power oscillation amplitude can be controlled during the size floating of the propeller thrust, and the propeller shaft wear is reduced.

[0004] The application is implemented by the following technical scheme:

[0005] The application discloses a double-water-jet-propeller thrust layering optimization distribution method. A mechanical model of a double-water-jet-propeller of a basic structure unmanned ship is constructed, a first layer thrust distribution optimization model is obtained through region division and vector synthesis, and the distribution thrust vector is obtained by solving, so that the first distribution is completed. The minimum distance method is used to perform the second distribution under the condition that the equal limitation condition between the reverse bucket and the thrust is added, so that the reverse bucket angle of the double propeller and the corresponding main engine power are obtained. When the singularity phenomenon occurs in the second layer distribution, the thrust distribution process is not intervened, and the jet flow velocity is controlled alone, so that the thrust optimization is realized.

[0006] The first layer thrust distribution optimization model is specifically min F,s F T F+s T Qs, s.t.MF = tau + s,

[0007]

[0008] Wherein: lambda i,j >= 0, i = 1, 2, j = 1, 2.

[0009] The present application relates to a system for implementing the above method, comprising: an unmanned ship control system, a water jet propeller, a communication device and a propeller control module, wherein: the unmanned ship control system obtains the PWM signal and the electric control signal required by the propeller according to the two-side propeller nozzle angle, the hopper angle and the propeller rotation speed parameter instruction output by the propeller control module; the water jet propeller responds to the signal output by the propeller control module, so that the two-side propeller generates the expected thrust; the communication device receives the left and right propeller parameters output by the propeller control module and feeds back the real-time propeller working condition to the control system; and the propeller control module calculates the expected propeller parameters according to the required resultant force and the feedback propeller parameters, and sends them to the unmanned ship.

[0010] The unmanned ship control system comprises: a motion controller and a power manager, wherein: the motion controller converts the instruction calculated by the propeller control module into the PWM signal and the electric control signal, sends them to the left and right propellers, and monitors the rotation speed, the nozzle angle and the hopper angle data of the left and right propellers in real time; the electric governor controls the propeller to reach the specified rotation speed according to the PWM signal; and the power manager is responsible for power supply for all devices and records the voltage and current data in real time.

[0011] The water jet propeller comprises: a motor, a paddle, a nozzle and a hopper, wherein: the motor receives the electric governor current, so that the paddle rotates at the expected rotation speed to generate the expected thrust; the nozzle adjusts the rotation angle according to the electric control signal, changes the left and right directions of the thrust by changing the flow direction of the water flow; and the hopper adjusts the hopper rotation angle according to the electric control signal, and influences the size and positive and negative of the thrust by deflecting the water flow.

[0012] The propeller control module comprises: a thrust distribution unit and a host computer unit, wherein: the thrust distribution unit calculates the expected rotation speed value, the nozzle angle value and the hopper angle value of the propeller within the limit condition according to the required resultant force and the resultant moment of the unmanned ship, in combination with the real-time rotation speed, the nozzle angle and the hopper angle of the left and right propellers; the host computer unit receives the calculation results of the thrust distribution unit and sends them to the unmanned ship to control the left and right propellers of the unmanned ship to reach the expected data, and simultaneously receives the propeller data fed back by the unmanned ship in real time and sends them to the thrust distribution unit.

[0013] Technical effects

[0014] The present application limits the rotation angle range of the propeller nozzle in the first layer thrust distribution optimization model, ensures that the propeller nozzle angle does not exceed the rotation angle limit range under linear conditions, adjusts the angle within the limited speed, and in the second layer thrust distribution optimization model, adds the limitation of the rotation speed of the reverse bucket, responds to the particularity of the water jet propeller in the rotation range, propulsion and reverse principle, introduces the vector synthesis method, region division method and minimum distance method, realizes the thrust distribution of the double water jet propeller unmanned ship through the hierarchical optimization method under the condition of limiting the rotation range and rotation rate of the nozzle and reverse bucket, and puts forward a solution to the singularity phenomenon. Compared with the existing thrust distribution method, the present application can effectively take into account the negative force characteristics of the reverse bucket, utilize the influence of the reverse bucket on the thrust size, reduce the main engine power shock frequency and amplitude under the condition of thrust variation, reduce the main engine wear, and improve the accuracy of the unmanned ship control process. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The flowchart of the present application is shown in the figure;

[0016] Figure 2 The system diagram of the present application is shown in the figure;

[0017] Figure 3 The verification test equipment diagram of the present application is shown in the figure;

[0018] Figure 4 The region division schematic diagram is shown in the figure;

[0019] Figure 5 The propeller nozzle and reverse bucket flow speed adjustment method schematic diagram when the expected thrust is stable is shown in the figure;

[0020] Figure 6 The propeller nozzle and reverse bucket flow speed adjustment method schematic diagram when the reverse bucket changes greatly is shown in the figure;

[0021] Figure 7a The left and right propeller angle change situation schematic diagram during the lateral movement in the embodiment is shown in the figure;

[0022] Figure 7b The left and right propeller thrust size change situation schematic diagram during the lateral movement in the embodiment is shown in the figure;

[0023] Figure 8a The left and right nozzle flow speed change situation schematic diagram in the embodiment of different distribution methods is shown in the figure;

[0024] Figure 8b The reverse bucket angle change situation comparison schematic diagram between the present application and the no control method in the embodiment is shown in the figure;

[0025] Figure 9 The propeller nozzle flow speed change schematic diagram before and after the singularity treatment is shown in the figure;

[0026] Figure 10a The left and right propeller power change schematic diagram for turning condition test;

[0027] Figure 10b The left and right propeller power change schematic diagram for transverse movement condition test. DETAILED DESCRIPTION

[0028] As Figure 1 shown, a method for distributing thrust of a double water jet propeller is provided, comprising:

[0029] Step 1, for the structure and configuration of the double water jet propeller on the unmanned ship, a basic mechanical model of the double water jet propeller is constructed, specifically including:

[0030] Step 1.1, a mechanical model of the double water jet propeller is established to ensure that the resultant force of the two propeller thrusts is equal to the required resultant force, specifically: τ = MF, wherein: the resultant force vector τ = [F x ,F y ,τ z ], the two propeller thrusts F = [F1 F2] T , F1 and F2 are the thrust vectors of the respective propellers, and the form is F i = [F xi F yi ] T , i = 1, 2, and the propeller configuration matrix

[0031]

[0032] Step 1.2, the thrust distribution problem is summarized as an optimization problem, and a basic optimization function is constructed according to the mechanical model of the double water jet propeller, the optimization objective being to minimize the propeller power and maintain force balance, and the optimization function expression being: min F, s F T F+s T Qs, s.t. MF = τ + s, wherein: the quadratic term of the thrust F T F represents the propeller power, s ∈ R 3 is a relaxation variable, which functions to ensure that an optimal approximate solution is obtained for the optimization function when an exact solution cannot be obtained, and the penalty term s T Qs, wherein Q is a weight matrix, causing the relaxation factor to tend to be minimal.

[0033] Step 2, the region division idea and vector composition method are introduced to solve the non-convex problem of the propeller angle restriction in the mechanical model of the double water jet propeller, specifically including:

[0034] Step 2.1, a vector

[0035] where θ i,old , i = 1, 2 is the nozzle rotation angle at the previous time. Δθ max is the maximum change of the nozzle angle in a single control step, which can be calculated by the product of the maximum change rate of the nozzle angle and the control step time. The maximum change rate of the nozzle angle is related to the execution delay of the waterjet mechanism and can be measured by the controlled waterjet. To ensure that the nozzle angle at the next time is within the physical limit, the range of the nozzle rotation angle of the waterjet is limited. Let the maximum allowed positive nozzle angle be θ max , and the maximum allowed negative nozzle angle be θ min .

[0036] Step 2.2, the problem of discontinuous change of the thrust direction of the waterjet is solved by region division. Specifically, according to the characteristics of the thrust range of the waterjet, the maximum rotatable angle of the nozzle is used as a boundary to divide the entire plane into four regions, as shown in FIG. 2. After the required resultant force is input, the positive and negative of the two waterjets are determined in advance by the four regions, so that the thrust range of the other side of the waterjet can be ignored, and the vector resultant force synthesis constraint condition is kept convex. Figure 4

[0037] Step 3, the scenario where both waterjets are positively propelled is considered, and the first layer thrust distribution optimization model obtained in step 1-2 is solved to obtain the thrust vector of the required resultant force distributed to the two waterjets. Then, the two waterjets rotate to the required angle according to their respective vectors to complete the first distribution.

[0038] The first layer thrust distribution optimization model is specifically as follows: min F,s F T F+s T Qs, s.t. MF = τ + s,

[0039]

[0040] where λ i,j ≥ 0, i = 1, 2, j = 1, 2.

[0041] Step 4, according to the minimum distance method, the second distribution is performed under the added equality constraint condition between the bucket and the thrust to obtain the bucket angle of the double waterjet and the corresponding waterjet power, which specifically includes:

[0042] Step 4.1, a relationship model of the thrust size of the waterjet, the nozzle flow rate v j , the nozzle angle θ, the ship speed u, and the bucket angle γ is constructed, and then the relationship between the thrust of a single waterjet and its nozzle flow rate and its bucket angle is derived, which is specifically as follows: F x = ρA​j v j (v j cosθ-u)·cosγ, where: ρ is the fluid density, A j is the nozzle area, and both are constants. The nozzle angle θ has been obtained from the above step 3.1. The longitudinal speed u of the ship is obtained in real time by the sensor during the driving process of the unmanned boat and can be regarded as a known quantity. Let F x / cosθ·ρA j =F, the relationship between the thrust of a single propeller, its nozzle velocity and its bucket angle is obtained as follows: Where: u / cosθ=e is a known number; nozzle velocity v j The angle γ of the bucket is satisfied: The nozzle flow rate v j With the bucket angle γ as the coordinate axis, a two-dimensional plane is constructed. The nozzle flow rate value and the bucket angle value of the water jet propulsion system at each moment can find corresponding points in the plane. For example, assuming that the propulsion system needs to generate thrust F1 at a certain moment, substitute F1 into formula (9), and we have That is, the bucket angle γ is related to the nozzle flow velocity v j Function curve, any point on the curve (v j ,γ), the thruster can generate the target thrust F1. Therefore, it is only necessary to change the thruster state point (v j ,γ) is moved to the function curve corresponding to the target thrust in some way, so that the thruster can generate the target thrust with the optimal combination of nozzle flow rate and bucket angle.

[0043] Step 4.2: Scale the vertical axis of the two-dimensional plane of the nozzle velocity and the bucket angle in step 4.1, and ignore the known quantity e whose value is related to the ship state. The function expression after scaling by the scaling coefficients ξ1 and ξ2 on both sides should be: When the required thrust changes, the thruster searches for the position closest to the function curve direction determined by the function expressions on both sides from the initial state, allowing the bucket to participate in the thrust change process.

[0044] Step 4.3: When solving the vertical point, multiple solutions may appear. When multiple solutions appear, set the horizontal coordinate v of the corresponding point of the thruster state j The horizontal coordinate v of the i-th vertical point found with the corresponding point ji The difference is dv ji , the vertical coordinate of the point corresponding to the thruster state γξ m ,m=1,2 and the vertical coordinate γ of the i-th vertical point i ξ m ,m=1,2The difference is dγ iBased on the idea of ​​balancing the propeller power adjustment and the bucket angle adjustment, the solution with similar adjustment ranges of the nozzle flow rate and the bucket angle is preferred, that is, dv ji +dγ i The corresponding solution when the maximum value is taken. Therefore, the solution of the vertical point can be summarized as the optimization problem (11):

[0045]

[0046] Preferably, during the solution process of steps 4.2-4.3, when the subsequent thrust does not change, or the change range is small, the target thrust corresponding curve will also remain unchanged or almost unchanged. Then when the nozzle flow rate of the propeller and the bucket angle have been adjusted to the curve along the vertical line corresponding to the minimum distance direction, the propeller state will no longer change, so that the bucket remains at a certain angle, resulting in power waste. Therefore, when the difference between the bucket angle and the optimal solution bucket angle is less than the set limit, it is considered that the propeller has entered a stable state, and the corresponding point of the propeller state is limited to the maximum speed of the bucket angle adjustment. According to the positive and negative thrust of the propeller at this time, it is gradually adjusted to the maximum or minimum value of the bucket angle. The schematic diagram of the specific adjustment method is shown as follows. Figure 5 shown.

[0047] Preferably, the bucket rotation process needs to be limited by the rotation rate. When the bucket angle differs greatly from the expected angle, the bucket needs to execute the process time to rotate to the expected angle. During this process, it is impossible to adjust the propeller speed according to the intermediate bucket angle to ensure that the target thrust is generated at every moment. Therefore, when the bucket cannot rotate to the expected angle within a single time step, the corresponding point of the propeller state is set to the maximum change value Δγ of the bucket angle within a single control step. max To restrict rotation toward the target, Figure 6 At the same time, during the bucket rotation process, the bucket angle value at each step is substituted into the vertical line corresponding to the minimum distance obtained by the second-level optimization process to determine the nozzle flow rate value. This can limit the bucket rotation rate and ensure the stability of the propeller power during the bucket rotation process.

[0048] Step 5. According to the left and right thruster nozzle flow rates and the bucket angle results obtained in step 4, the simulation object is controlled to perform specific execution, and the nozzle flow rate is controlled separately in the second distribution to deal with the singularity phenomenon that may occur in the distribution process. That is, in the thrust distribution process, when the longitudinal force or lateral force required by the unmanned boat at a certain point in time is not a small amount, but the thrust of the thruster solved by the distribution is a small amount, specifically: when a singularity phenomenon occurs, do not intervene in the thrust distribution process, and directly fix the main engine power and the bucket angle of the lower layer. This can ensure the stability of the main engine power when a singularity phenomenon occurs in the thrust distribution, and ensure the stability of the system.

[0049] Let the unmanned ship propeller configuration data be l x1 = l x2 = l x = -2, l y1 = -l y2 = l y = 1, and set two working conditions specifically include:

[0050] Working condition 1) the unmanned ship performs variable speed transverse movement, that is, the longitudinal speed and the total torque are kept zero, and the required transverse force expression is set as F y = 100sin (πt / 5)N, the thrust distribution is performed on the target resultant force, and the distribution effect of the algorithm is verified.

[0051] Working condition 2) assuming that the unmanned ship is subjected to time-varying environmental disturbance force during vector movement, in order to ensure stable vector movement, the water jet propeller needs to generate a corresponding resultant force to resist the time-varying environmental disturbance force. Three simulations are set as follows, simulation 1: the target vector movement of the unmanned ship is set as transverse movement, and it is assumed that the transverse movement is subjected to a time-varying environmental disturbance force between 50N and 100N. Simulation 2: the target vector movement of the unmanned ship is set as transverse movement, and it is assumed that the transverse movement is subjected to a time-varying environmental disturbance force between 25N and -100N. Simulation 3: the target vector movement of the unmanned ship is set as rotation movement, and it is assumed that the rotation movement is subjected to a time-varying environmental disturbance torque between 100N·m and -200N·m.

[0052] According to the above propeller setting and target working condition, through simulation experiment verification, the jet flow rate, jet angle and bucket angle change diagram of each propeller are obtained. According to Fig. 7, the distribution effect of the distribution method of the design is good, the jet angle can be controlled to rotate to the target angle at the maximum rate, and it can be kept stable; according to Fig. 8, the method can timely rotate the bucket when the propeller thrust oscillates, compared with other thrust distribution methods without considering the influence of the bucket on the thrust, the rotation of the bucket can reduce the oscillation frequency and amplitude of the main engine power; according to Figure 9 It can be seen that when the singular phenomenon occurs in the thrust distribution system, the stability of the main engine power can be improved and the shaft wear can be reduced.

[0053] After specific actual test, the above method is run on a ship model with a length of 3m and a width of 0.85m, the working conditions are set as simulation 1 and simulation 3, the transverse movement working condition is set as: the unmanned ship moves to the left, the longitudinal force and the moment are kept as zero, the initial transverse force is 20N. At the 10th second, the transverse force is increased from 20N to 40N, from the 13.5th second, the transverse force starts to oscillate between 20N and 40N, the oscillation frequency is 1 / s, and stops at the 17.5th second. The rotation working condition is set as: the unmanned ship performs the rotation movement, the transverse force and the longitudinal force are kept as zero, the initial moment is 12.5N·m, at the 9th second, the moment is increased from 12.5N·m to 25N·m, and the propeller enters the stable state. From the 13th second, the moment oscillates between 12.5N·m and 25N·m with a frequency of 2s, and stops at the 19th second. The experimental data obtained are shown in Fig. 10, wherein, Figure 10a is the power change of the left and right propellers in the transverse movement working condition, Figure 10b is the power change of the left and right propellers in the rotation working condition.

[0054] Compared with the prior art, it can be seen from the semi-physical simulation test results of the above two working conditions that, whether in the transverse movement working condition or in the rotation working condition, the change of the instruction can be responded in time, and is consistent with the expected change. On this basis, the power required can be delayed to more than 1s in the power required large amplitude change. In the oscillation working condition of the resultant force or the moment of the unmanned ship, the power change amplitude of the forward thrust propeller in the working condition can be reduced by a certain amplitude, and the power decrease speed is effectively slowed down, the main engine power is stabilized, and the control of the main engine power adjustment frequency, the reduction of the shaft wear are achieved.

[0055] The above specific implementation can be adjusted in different ways by those skilled in the art without departing from the principles and purposes of the present application, the protection scope of the present application is subject to the claims and is not limited by the above specific implementation, and each implementation scheme within the scope is subject to the present application.

Claims

1. A method for optimizing the thrust distribution of dual water jet propulsion systems by layering, characterized in that: By constructing a basic mechanical model of the unmanned watercraft's dual waterjet propulsion system, the first-layer thrust distribution optimization model is obtained through regional division and vector synthesis methods, and the thrust vector is solved to complete the first distribution. Then, through the minimum distance method, a second distribution is performed under the equation constraint between the bucket and thrust, and the bucket angle of the dual propeller and the corresponding main engine power are obtained. Finally, when a singularity phenomenon occurs in the second-layer distribution, the thrust distribution process is not intervened, and the nozzle flow rate is directly controlled separately to achieve thrust optimization. Specifically, the following steps are taken: Step 1: Construct a basic mechanical model of the dual water jet propulsion system based on its structure and configuration on the unmanned boat. Step 2: Introduce the idea of ​​regional division and vector synthesis method to solve the non-convex problem of propeller angle limitation in the mechanical model of dual water jet propulsion; Step 3: Consider the scenario where both thrusters are in forward propulsion. Solve the first-level thrust distribution optimization model obtained in Steps 1 and 2. After obtaining the thrust vectors for distributing the required resultant force to the two thrusters, the two thrusters rotate to the required angles according to their respective vectors to complete the first distribution. Step 4: Based on the minimum distance method, a second distribution is performed under the added constraint of the equation between the bucket and the thrust, and the bucket angle of the dual thrusters and the corresponding thruster power are obtained.

2. The method for optimizing the thrust distribution of dual water jet propulsion systems according to claim 1, wherein: The first-level thrust distribution optimization model is specifically as follows: ,st , , , ,in: , i=1,2, j=1,2, is the nozzle rotation angle at the previous moment, The nozzle represents the maximum change in nozzle angle within a single control step. The maximum allowable positive angle of the nozzle is , the maximum allowable negative angle , two thrusters thrust , F1 and F2 are the thrust vectors of each thruster, and their forms are , thruster configuration matrix , the resultant force vector , the quadratic thrust term represents the propeller power, is a slack variable, which is used to ensure that the optimization function will obtain an optimal approximate solution when the exact solution cannot be obtained. The penalty term middle is the weight matrix, which minimizes the relaxation factor.

3. The method for optimizing the thrust distribution of dual water jet propulsion systems according to claim 2, wherein: The step 1 specifically includes: Step 1.1: Establish a mechanical model of the dual water jet propulsion system to ensure that the combined thrust of the two propulsion systems is equal to the required resultant force. Specifically: ; Step 1.2: The thrust distribution problem is summarized as an optimization problem, and a basic optimization function is constructed based on the mechanical model of the dual waterjet propulsor. The optimization objectives are to minimize the propulsor power and maintain force balance. The step 2 specifically includes: Step 2.1: Construct vector 、 , where: the maximum change is calculated by multiplying the maximum change rate of the nozzle angle by the control step time. The maximum change rate of the nozzle angle is related to the execution delay of the waterjet propulsion mechanism and is obtained by actual measurement of the controlled waterjet propulsion. In order to ensure that the nozzle angle at the next moment is within the physical limit, the rotation angle range of the propeller nozzle is limited; Step 2.2: Resolve the discontinuous change in thrust direction of the waterjet through regional division. Specifically, based on the thrust range characteristics of the waterjet, the entire plane is divided into four regions, bounded by the maximum rotatable angle of the nozzle. After the required resultant force is input, the four regions are divided. By pre-determining the positive and negative values ​​of the thrusters on both sides, the thrust range of the other side can be ignored, ensuring that the thrust vector synthesis constraint retains convexity. In step 5, based on the left and right thruster nozzle flow rates and the bucket angle results obtained in step 4, the simulation object is controlled to perform specific execution, and the nozzle flow rates are individually controlled in the second distribution to deal with the singularity phenomenon that may occur during the distribution process. That is, during the thrust distribution process, when a singularity phenomenon occurs, the thrust distribution process is not intervened, and the main engine power and the bucket angle of the lower layer are directly fixed. This ensures the stability of the main engine power when a singularity phenomenon occurs in the thrust distribution, thereby ensuring the stability of the system.

4. The method for optimizing the thrust distribution of dual water jet propulsion systems according to claim 3 is characterized in that: The step 4 specifically includes: Step 4.1: Construct the thrust and nozzle velocity of the water jet , nozzle angle , ship speed Angle of bucket The relationship model of the thrust of a single propeller, its nozzle velocity and its bucket angle is derived, which is specifically: ,in: is the fluid density, is the nozzle area, and the two are constants, the longitudinal speed of the ship In order to obtain the real-time information through the sensors during the driving process of the unmanned boat, The relationship between the thrust of a single propeller, its nozzle velocity and its bucket angle is obtained as follows: ,in: is a known number; nozzle flow rate Angle of bucket Satisfy between: , with nozzle flow rate Angle of bucket As the coordinate axis, a two-dimensional plane is constructed. The nozzle velocity value and the bucket angle value of the water jet propulsion device at each moment have corresponding points in the plane. Step 4.2: Scale the vertical axis of the two-dimensional plane of the nozzle velocity and the bucket angle in step 4.1, and ignore the known quantity e related to the ship state, and obtain the scaling coefficient on both sides. 、 Scaling function expression When the required thrust changes, the thruster searches for the position with the shortest distance from the initial state in the direction of the function curve determined by the function expressions on both sides; Step 4.3: When multiple solutions appear in the process of solving the vertical point, the solution of the vertical point is summarized as an optimization problem: ,st , where: the horizontal coordinate of the point corresponding to the thruster state The horizontal coordinate of the i-th vertical point found with the corresponding point The difference is , the vertical coordinate of the point corresponding to the thruster state The vertical coordinate of the i-th perpendicular point The difference is .

5. The method for optimizing the thrust distribution of dual water jet propulsion systems according to claim 4 is characterized in that: When the difference between the bucket angle and the optimal solution bucket angle is less than the set limit, the propeller is considered to have entered a stable state. The corresponding point of the propeller state is limited to the maximum speed of the bucket angle adjustment. Depending on the positive or negative thrust of the propeller at this time, the bucket angle is gradually adjusted to the maximum or minimum value.

6. The method for optimizing the thrust distribution of dual water jet propulsion systems according to claim 4 is characterized in that: When the bucket cannot rotate to the expected angle within a single time step, the corresponding point of the thruster state is set to the maximum change value of the bucket angle within a single control step. In order to limit the rotation toward the target, during the bucket rotation process, the bucket angle value of each step is substituted into the vertical line corresponding to the minimum distance obtained by the second-level optimization process to determine the nozzle flow rate value.

7. A dual waterjet thrust layered optimization distribution system for implementing the method according to any one of claims 1 to 6, characterized in that: include: Unmanned boat control system, water jet propulsion, communication equipment and propeller control module, among which: the unmanned boat control system solves the PWM signal and electronic control signal required by the propeller according to the propeller nozzle angle, bucket angle and propeller speed parameter instructions of the two sides of the propeller output by the propeller control module; the water jet propulsion responds according to the signal output by the propeller control module, so that the propellers on both sides generate the expected thrust; the communication equipment receives the left and right propeller parameters output by the propeller control module, and feeds back the real-time propeller working conditions to the control system; the propeller control module performs calculations at the next moment according to the required resultant force and the feedback propeller parameters, obtains the expected propeller parameters, and sends them to the unmanned boat.

8. The dual water jet thrust layered optimization distribution system according to claim 7 is characterized in that: The unmanned boat control system includes: a motion controller and a power manager, wherein: the motion controller converts the instructions calculated by the thruster control module into PWM signals and electronic control signals, sends them to the left and right thrusters, and monitors the left and right thruster speeds, nozzle angles, and bucket angle data in real time. The electronic regulator controls the thrusters to reach the specified speed according to the PWM signals. The power manager is responsible for powering all devices and recording voltage and current data in real time.

9. The dual water jet thrust layered optimization distribution system according to claim 7 is characterized in that: The water jet propulsion device includes: a motor, blades, a nozzle and a bucket, wherein: the motor receives an electronically controlled current to make the blades rotate at an expected speed to generate a desired thrust; the nozzle adjusts the rotation angle according to the electronic control signal, and changes the left and right direction of the thrust by changing the direction of the water flow; the bucket adjusts the rotation angle according to the electronic control signal, and affects the magnitude and positive and negative of the thrust by deflecting the water flow.

10. The dual water jet thrust layered optimization distribution system according to claim 7 is characterized in that: The thruster control module includes: a thrust distribution unit and a host computer unit, wherein: the thrust distribution unit calculates the expected speed value, nozzle angle value and bucket angle value of the thruster within the restriction conditions based on the resultant force and torque required by the unmanned boat, combined with the real-time speed, nozzle angle and bucket angle of the left and right thrusters; the host computer unit receives the calculation results of the thrust distribution unit and sends it to the unmanned boat, controls the left and right thrusters of the unmanned boat to achieve the expected data, and at the same time, receives the thruster data fed back by the unmanned boat in real time and sends it to the thrust distribution unit.

Images