Composite feedforward cooperative control method and system for propulsion of ship controllable-pitch propeller

Abstract

The invention provides a composite feedforward cooperative control method and system for propulsion of a controllable-pitch propeller of a ship. The method comprises the following steps: establishing a propulsion composite model comprising a ship load inquiry function model and a controllable-pitch propeller propulsion cooperative control model; identifying ship resistance characteristics in real time through a load inquiry model, predicting main engine power and propeller rotating speed requirements at different navigational speeds, and calculating a main engine power margin; setting a host security threshold based on the maximum persistent power margin; within the allowable range of the safety threshold value, three cooperative control modes are selected and executed in a self-adaptive mode according to the navigation working condition, wherein the three cooperative control modes include the pitch-accelerator joint control mode under the constant rotating speed of a main engine, the main engine rotating speed-accelerator joint control mode under the fixed pitch of a controllable-pitch propeller and the controllable-pitch propeller rotating speed-pitch joint control mode under the constant power of the main engine. According to the invention, through feedforward prediction and multivariable cooperation, navigational speed closed-loop stable control is realized, the problems of host overload, black smoke emission, high exhaust temperature and large control fluctuation are fundamentally avoided, and fuel economy and all-condition navigation safety are improved.

Description

Technical Field

[0001] This invention relates to the field of marine technology, and in particular to a composite feedforward cooperative control method and system for ship controllable pitch propeller propulsion. Background Technology

[0002] A controllable pitch propeller is a variable pitch propeller that can meet different navigation conditions by changing the pitch / direction and rotation speed. It is characterized by easy operation and high maneuverability. Controllable pitch propeller devices have broad application prospects in military ships, ocean-going survey ships, passenger roll-on / roll-off ships, scientific research vessels, engineering vessels, and ships navigating ice-covered areas.

[0003] In a controllable pitch propulsion system, the power output from the main engine is transmitted to the controllable pitch propulsion system via a hydraulic coupler and intermediate shaft. The controllable pitch propulsion system then generates thrust to propel the ship forward, turn, or reverse. During ship acceleration, if the speed and pitch of the controllable pitch propulsion system are not well matched, it will cause a sharp change in the thrust of the controllable pitch propulsion system. This, combined with the influence of random factors such as sea state disturbances and changes in the ship's attitude, can easily lead to main engine overload, high exhaust temperature, black smoke, and severe fluctuations in speed-throttle-pitch, affecting the ship's navigation stability and main engine performance. Frequent pitch control operations also lead to severe wear and oil leakage.

[0004] On the other hand, current ship controllable pitch propeller propulsion control modes include main engine constant speed control mode and controllable pitch propeller fixed pitch control mode, both of which are single-objective setpoint control. They lack feedforward control and composite control strategies based on ship load inquiry function. In particular, the current ship speed open-loop control has problems such as unstable speed and low main engine efficiency.

[0005] Therefore, there is an urgent need for an intelligent propulsion control method that can achieve stable closed-loop speed control, stable main engine load, good economy, and adaptability to all operating conditions (especially navigation in ice-covered areas). Summary of the Invention

[0006] The purpose of this invention is to provide a composite feedforward coordinated control strategy for ship propulsion that can avoid problems such as main engine overload, high exhaust temperature, black smoke, large fluctuations in speed-throttle-pitch (unstable control), excessive wear of controllable pitch propellers, and difficulties in ice-covered areas. This strategy achieves optimal control of controllable pitch propeller propulsion, maintains stable ship speed, and optimizes main engine performance, thereby improving the safety and maneuverability of ships in adverse sea conditions and ice-covered areas.

[0007] To achieve the above objectives, this invention proposes a composite feedforward cooperative control method for ship controllable pitch propeller propulsion, comprising the following steps: S1: Establish a composite model of controllable pitch propeller propulsion to clarify the collaborative relationship between various components of the controllable pitch propeller propulsion system. The composite propulsion model includes a ship-engine-propeller relationship model, a propulsion main engine characteristics and limitation model, a hydraulic coupler characteristics model, a controllable pitch propeller characteristics model, a controllable pitch propulsion collaborative control model, and a ship load inquiry function model. The propulsion main unit characteristics and limitation models include constant pitch FPP propulsion, variable pitch CPP propulsion, propulsion main unit speed characteristics, propulsion main unit load characteristics, and limitation characteristics of the propulsion main unit's allowable operating range; By establishing the relationship between the controllable pitch propeller speed, pitch and torque through the controllable pitch propeller characteristic model, the characteristic curve of the controllable pitch propeller is obtained. The deviation between the ideal design curve and the actual operation curve shows the performance of the propulsion system and its operating conditions. A coordinated control model for controllable pitch propeller propulsion is established to establish coordinated control between main engine speed and throttle, hydraulic coupler output speed, and controllable pitch propeller speed and pitch. The ship load interrogation function model collects real-time data on ship speed, main engine power, main engine speed, controllable pitch propeller speed, and propeller pitch. Based on the data-driven extended Kalman filter (EKF) algorithm, the ship's resistance characteristics are identified online. Based on the identification results, the relationships between main engine power and ship speed (i.e., the first mapping relationship between ship speed and main engine power) and between controllable pitch propeller speed and ship speed (i.e., the second mapping relationship between ship speed and propeller speed) are dynamically established. Based on the first and second mapping relationships, the required main engine power and propeller speed at different ship speeds are predicted in advance. The real-time difference between the current main engine power and the maximum continuous main engine power is calculated as the current power margin. A power margin limit threshold is set to determine the maximum continuous main engine power margin Δ. P max Based on the maximum continuous power margin Δ P max， Set host security threshold d ME In this invention, the power margin limit threshold is set to be no less than 5% of the host's rated power; a host safety threshold is also set. d ME 95% of the maximum continuous power margin Δ P max ,Right now d ME =0.95(Δ P max ); S2: Calculate the speed deviation between the set speed and the actual speed, input the speed deviation into the ship speed closed-loop asymptotic control loop, and generate a gradually changing desired speed sequence. S3: For each desired speed value in the desired speed sequence, invoke the ship load query function model to predict the main engine power and controllable pitch propeller speed required to achieve the desired speed; calculate the power demand increment based on the predicted main engine power and the current main engine power; compare the power demand increment with a predetermined main engine safety threshold; if the power demand increment (main engine pre-increase power ΔP) is less than or equal to the pre-increase power ΔP, then... ME Exceeding the host security threshold d ME This generates a feedforward protection command to proactively reduce the controllable pitch propeller pitch and actively reduce the controllable pitch propeller thrust T. Even if the system accelerates due to inertia, there will be no overshoot problem, and the pre-increased power can still be guaranteed to be less than [a certain value]. d ME This ensures that the power demand during actual acceleration is always below the safety threshold, fundamentally preventing main engine overload and related malfunctions, avoiding problems such as black smoke from the main engine, high exhaust temperature, overload operation, and large fluctuations in speed-pitch-throttle (caused by unstable control), thereby optimizing ship propulsion performance and preventing frequent back-and-forth adjustments; The host security threshold d ME The calculation formula is: , In the formula, ΔP max This represents the maximum continuous power margin of the host (kW). d ME For host security threshold, P emax This represents the maximum continuous power of the main unit (kW). P p Propeller power (kW) β 1 represents the transmission efficiency of the hydraulic coupling and shaft system. β 2 represents the influence coefficient after the interaction between the ship and the paddle; S4: At the host security threshold d ME Within the permissible range, the controllable pitch propeller propulsion cooperative control model is used to select and execute the following cooperative control modes according to the navigation conditions, thereby achieving stability of main engine performance and ship speed; the control modes include: Controlling ship speed in main engine constant speed mode v s At that time, it is adapted to the operating conditions of ocean navigation, with the main engine speed as a constant value for control, in conjunction with the main engine throttle. L Tracking pitch propeller H p The adjustment, namely the pitch-throttle joint control mode, is suitable for ocean navigation conditions; Adjustable pitch propeller fixed pitch H p Controlling ship speed in mode vs At that time, the pitch of the controllable propeller screw... H p The main engine speed is a constant value. n e Closed-loop control, coordinated with main engine throttle L According to the main unit speed n e Follow-up adjustment, i.e., main engine speed-throttle linkage control mode, is suitable for normal navigation conditions; Controlling ship navigation in adverse sea conditions in constant power mode v s At that time, use the main engine throttle. L The output speed of the hydraulic coupling is a constant value. n p - Pitch H p Cooperative control, namely the controllable pitch propeller speed-pitch joint control mode, is suitable for navigation in severe sea conditions or ice areas; These three boat speeds v s The control modes are all within the host security threshold. d ME It is conducted within permissible limits and is subject to the characteristics of the host and the constraints of the model.

[0008] In this invention's composite feedforward coordinated control method for ship controllable pitch propeller propulsion, the composite meaning refers to pitch-throttle joint control based on speed closed-loop stability control, main engine speed-throttle joint control, and controllable pitch propeller speed-pitch joint control; the feedforward meaning refers to the ship load inquiry function, which identifies the ship's resistance characteristics based on EKF, and uses the power and speed required for ship speed in feedforward control to improve speed; the coordinated control meaning refers to the systematic integrated joint control of the ship, main engine, hydraulic coupler, and controllable pitch propeller; and the three ship speeds... v s The control mode is selected based on sea conditions and navigation conditions. When the ship enters or leaves port or passes through special channels, it uses manual control mode. When the ship is sailing on the open ocean, these three control modes can be selected automatically or manually. The main engine constant power mode is automatically selected according to severe sea conditions. The main engine constant speed control is used when the ship's speed is stable. When the ship's speed is stable, it uses throttle-pitch linkage control to achieve fuel-saving navigation. For other navigation conditions, constant pitch control is preferred to reduce wear caused by frequent propeller hub slippage. The main engine speed-throttle linkage control maintains stable speed and main engine power, which effectively prevents main engine overload, high exhaust temperature, black smoke, and unstable speed-pitch-throttle (caused by unstable control). It improves the thermal efficiency and thermal balance of the main engine and achieves automatic control capabilities for stable ship speed, safe and reliable ship handling, and rapid response.

[0009] Furthermore, in step S1, the ship-engine-propeller relationship model includes an engine-propeller characteristic sub-model, a ship resistance characteristic sub-model, and a ship-propeller characteristic sub-model. The formula for the engine-propeller characteristic sub-model is: ; In the formula, J To increase the rotational inertia of the shaft system, n e For the main unit's rotation speed, n p For the controllable pitch propeller speed, M e For the main unit to output torque, M p For the torque of the controllable pitch propeller, M m This refers to the frictional torque of the shaft system. ; In the formula, P p For controllable pitch propeller power, P ME This refers to the output power of the main unit. or c For shaft transmission efficiency.

[0010] The formula for the ship resistance characteristic sub-model is: ; In the formula, R For ship resistance, α R The drag coefficient, v s For ship speed, m This is a ship index.

[0011] Furthermore, in step S1, the formula for the ship-oar characteristic sub-model is: ; In the formula, M For ship quality, v s For ship speed, T For the thrust of the controllable pitch propeller, ∑ T This indicates propulsion by two or more controllable pitch propellers. R For the resistance of the ship's motion; ; In the formula, P R To maximize the propulsion power of the controllable pitch propeller, or s For hull efficiency, or p To improve the efficiency of the controllable pitch propeller in flowing water, or x To improve the rotational efficiency of the controllable pitch propeller P pThis refers to the power of the controllable pitch propeller.

[0012] Furthermore, in step S1, the main engine characteristics and limiting models include the controllable pitch propeller fixed pitch FPP propulsion mode, variable pitch CPP propulsion mode, main engine speed characteristics, main engine load characteristics, and limiting characteristics of the main engine's allowable operating range: When the constant pitch FPP propulsion mode is constant pitch control at a certain pitch, it enters the main engine speed and throttle coordinated control mode. The variable pitch CPP propulsion mode is a composite coordinated control mode of main engine speed-throttle-pitch; The main engine speed characteristics are obtained by constant throttle control at different throttle levels, resulting in full-load speed characteristics, overload speed characteristics, and partial-load speed characteristics. Based on these main engine speed characteristics, the torque curve representing the relationship between the main engine torque and speed is obtained. ; The host load characteristic is obtained by constant speed control at different speeds to achieve the host's economic load, power curve. Under constant speed, the main engine power changes linearly with increasing load; The operating range of the host is the maximum and minimum power that the host can reach at various speeds, as well as the highest and lowest speeds that the host can reach under various loads.

[0013] The main engine limiting characteristic curves include the constant torque limiting curve and the constant exhaust temperature limiting line, which are used to limit the main engine's excessive mechanical load and excessive thermal load, respectively. The aforementioned characteristic curves visualize characteristic changes. The calibration characteristic curves, obtained through main engine bench tests, controllable pitch propeller water flow tests, and new ship launch sea trials, reflect the ideal design characteristics of the ship-engine-propeller system. The degree to which the characteristic curves deviate from the calibration characteristic curves during actual operation reflects changes in the ship's propulsion performance and operating conditions.

[0014] Furthermore, in step S1, the hydraulic coupler characteristic model converts the main engine's speed and torque into the controllable pitch propeller's speed and torque. The relationship between the input / output speed and torque and the hydraulic coupler's gear ratio is visualized through the hydraulic coupler's operating characteristic curve. When the hydraulic coupler is engaged, the main engine torque, hydraulic coupler torque, and controllable pitch propeller torque are balanced. The optimal match between the main engine operating conditions and the controllable pitch propeller is achieved through the hydraulic coupler's characteristic relationship, preventing propeller overload or underload. This invention uses a hydraulic coupler that can both regulate the propeller speed and stabilize the main engine speed, buffering the direct impact of the propeller on the main engine.

[0015] Furthermore, in step S1, the controllable pitch propeller propulsion characteristic model includes a controllable pitch propeller torque sub-model, a controllable pitch propeller thrust sub-model, a controllable pitch propeller power sub-model, and a controllable pitch propeller flow efficiency sub-model: The formula for the controllable pitch propeller torque sub-model is: , In the formula, M p For controllable pitch propeller torque, K M This is the torque coefficient of the controllable pitch propeller. r The mass density of water, D The diameter of the controllable pitch propeller. n p This refers to the controllable pitch propeller speed; The formula for the controllable pitch propeller thrust sub-model is: , In the formula, T For controllable pitch propeller thrust, K T This is the thrust coefficient of the controllable pitch propeller. D The diameter of the controllable pitch propeller. n p This refers to the controllable pitch propeller speed; The formula for the controllable pitch propeller power sub-model is: , In the formula, P p For controllable pitch propeller power, K M This is the torque coefficient of the controllable pitch propeller. r The mass density of water, D The diameter of the controllable pitch propeller. n p This refers to the controllable pitch propeller speed; The formula for the flow efficiency sub-model of the controllable pitch propeller is: , In the formula, or p To improve the efficiency of the controllable pitch propeller in flowing water, T For controllable pitch propeller thrust, v p For controllable pitch propeller advance speed, n p For the controllable pitch propeller speed, D The diameter of the controllable pitch propeller. M p This refers to the torque of the controllable pitch propeller.

[0016] Furthermore, in step S1, the controllable pitch propeller propulsion coordinated control realizes the cascaded coordinated control of main engine speed control, throttle control, main engine speed and load limitation, hydraulic coupling adjustment of controllable pitch propeller speed and controllable pitch propeller pitch adjustment.

[0017] Furthermore, in step S1, the ship load inquiry function model identifies the ship's resistance characteristics based on the EKF by using the characteristic relationship between ship speed and main engine power, and the characteristic relationship between propeller speed and ship speed. It also calculates the power margin as the difference between the current power and the maximum continuous power of the main engine. The power margin limit value cannot be less than 5% of the rated power. It predicts the required main engine power and propeller speed at different ship speeds in advance, and performs closed-loop control of ship speed to prevent main engine overload and unstable speed.

[0018] Furthermore, in step S2, at the host security threshold d ME Within permissible limits, the process of composite feedforward coordinated control of pitch control propeller pitch must satisfy the following relationship: , In the formula, P p For controllable pitch propeller power, P emax This is the maximum continuous power of the host. β 1 represents the transmission efficiency of the hydraulic coupling and shaft system. β 2 represents the influence coefficient after the interaction between the ship and the paddle; Among them, the main unit output power P ME Less than the host's maximum continuous power P emax ,Right now P ME ≤ P emax Main unit output power P ME for: , In the formula, k 1. k 2 and k 3 represents the external characteristic curve parameters of the host computer. n e This refers to the main unit's rotational speed; Maximum continuous power margin Δ of the host P max for: , Host security threshold d ME for: , In the formula, d ME Δ is the host security threshold. P max This is the maximum continuous power margin of the host. Pemax This represents the maximum continuous power of the host unit.

[0019] Furthermore, in step S3, when controlling the ship's speed in the main engine constant speed mode, under ocean navigation conditions, the pitch is constant with the main engine speed. H p Position loop servo control, coordinated with main engine throttle L Tracking pitch propeller H p The adjustment, throttle-pitch coordinated control model is as follows: , , In the formula, L For the main engine throttle, H p The propeller pitch is... v s For the ship's speed, n p This refers to the propeller speed; D λ is the diameter of the controllable propeller; λ is the pitch. H p With speed v s Rotation speed n p The two-variable function between them, through flexible adjustment of pitch H p and rotational speed n p These two parameters determine the optimal propulsion performance, maneuverability, and main engine protection under different operating conditions; Ψ represents the engine throttle. L With pitch H p The function between these parameters was obtained through sea trials of the ship to determine the different pitches of the controllable propeller at constant main engine speed. H p -Main power P ME The numerical curve of throttle L.

[0020] At host security threshold d ME Within permissible limits, when the ship accelerates under constant engine speed mode, the composite feedforward collaborative control synchronously increases the pitch-throttle ratio; when the ship decelerates, the composite feedforward collaborative control synchronously decreases the pitch-throttle ratio, thus achieving pitch-throttle linkage control. The lead time of the composite feedforward collaborative control is less than the inertial time of the ship's propulsion system.

[0021] Due to factors such as shipboard fouling, propeller blade deformation, wind, waves, and currents, the throttle-pitch relationship is complex and time-varying. L = P ( H pThe experimental numerical curves obtained from the sea trials of a new ship can be used to obtain continuous values ​​through polynomial interpolation during actual operation. The constant engine speed control mode controls the ship's speed by adjusting the propeller pitch. This offers superior performance compared to conventional ship speed control via propeller speed adjustment, achieving the lowest possible SFOC (Speed, Load, and Oxide) at this constant speed. The pitch-throttle linkage aims to control the ship's speed at a constant engine speed while preventing overloading, thus avoiding problems such as large fluctuations in speed-pitch-throttle, black smoke from the main engine, and high exhaust temperatures.

[0022] Meanwhile, under stable operating conditions during ocean navigation, the ship's speed is stable, and the system automatically selects the lowest SFOC control. The lowest SFOC operating range is determined by the SFOC-main engine power polynomial curve interpolation method, and energy-saving optimization control is achieved by adjusting the throttle and pitch in a coordinated manner to ensure that both the ship's speed and the main engine speed are stable.

[0023] Furthermore, when controlling the ship's speed in the controllable pitch propeller constant pitch mode, the main engine speed closed-loop control, with the controllable pitch propeller pitch as a constant value, is achieved using a PID controller combined with dynamic compensation ε. This is coordinated with the main engine throttle tracking and adjusting the main engine speed accordingly. The main engine speed-throttle coordinated control model is as follows: , In the formula, K p , K I and K d These are the adjustable proportional coefficient, integral coefficient, and differential coefficient, respectively. n e For the main engine speed deviation, e To dynamically compensate for and control the uncertainties, this invention employs a deep learning algorithm to obtain... e Compensation value.

[0024] At host security threshold d ME Within permissible limits, during ship acceleration in constant pitch mode, the composite feedforward cooperative control synchronously increases the main engine speed. n e and throttle L When the ship decelerates, the composite feedforward collaborative control synchronously reduces the main engine throttle and main engine speed, realizing main engine speed-throttle linkage control. The lead time of the composite feedforward collaborative control is less than the inertia time of the ship's propulsion system. This invention differs from conventional main engine speed-throttle regulation systems where the throttle passively follows the governor output. The main engine speed-throttle linkage control aims at constant pitch speed control. In the initial stage of control, the main engine speed and throttle are adjusted synchronously at the same time. Then, a cascade control is implemented with throttle regulation as the inner loop and main engine speed regulation as the outer loop. The main engine is kept from overloading, preventing problems such as large speed-throttle fluctuations, black smoke from the main engine, and high exhaust temperature.

[0025] Furthermore, when controlling ship speed in the main engine constant power (constant throttle) mode, i.e., the controllable pitch propeller speed (hydraulic coupler output speed) - pitch coordinated control mode, is suitable for ship navigation in harsh sea conditions. The controllable pitch propeller speed - pitch coordinated control, with the main engine throttle scale (fuel injection quantity) as a constant value, aims to maintain the thermal balance of the main engine. The controllable pitch propeller speed - pitch coordinated control under main engine constant power is... , , , In the formula, P ME This refers to the output power of the main unit. K o For the controllable pitch propeller propulsion coefficient, C(H p / D) For controllable pitch propeller thrust, v s For ship speed, L This refers to the engine throttle (fuel injection quantity). n p For the controllable pitch propeller speed, H p For the pitch of the controllable propeller, or o To improve efficiency, S For slippage rate, K G γ is the adjustable ratio of the variable speed hydraulic coupling; γ is a function of the main engine power and throttle, calibrating the relationship between the main engine power and the fuel injection quantity; Γ is the thrust related to the pitch of the controllable propeller, meaning the adjustment of the pitch. H p It allows for quick and direct setting of thrust magnitude and direction, enhancing the high maneuverability, high controllability, and wide adaptability of the controllable pitch propeller.

[0026] When the main engine throttle controller keeps the throttle constant, the main engine speed cannot remain constant. The required speed for the controllable pitch propeller is then output through the hydraulic coupling. n p Simultaneously adjusted via pitch controller H p The prerequisite for coordinated control of controllable propeller speed and pitch is the main engine power. P ME Constant throttle position LTo achieve a constant throttle value and maintain the thermal balance of the main engine, the ship's speed is controlled under constant main engine power. During ship speed control, sea state disturbances can cause the ship's speed to deviate from the pilot's set speed. For example, when facing headwinds or currents, the ship's speed decreases. The composite feedforward control reduces the propeller pitch while adjusting the output speed of the hydraulic coupler. When sailing with the wind or current, the ship's speed increases. The composite feedforward control increases the output speed of the hydraulic coupler while adjusting the propeller pitch to maintain a constant main engine power, but the speed increases. Alternatively, the composite feedforward control reduces the output speed of the hydraulic coupler and the pitch of the controllable pitch propeller to reduce the main engine power and maintain a constant speed. The composite feedforward control synchronously adjusts the controllable pitch propeller speed-pitch, stabilizing the ship's main engine performance under adverse sea conditions, maintaining the thermal balance of the main engine, and preventing problems such as black smoke and high exhaust temperatures. The innovation of this invention's constant throttle control lies in adjusting the propeller speed through the hydraulic coupler to maintain a stable main engine speed under this constant throttle.

[0027] The ship uses two mass flow meters to detect the amount of oil entering the main engine. G 1 and return oil volume G 2. The fuel consumption of the main unit is calculated to be ∆. G = G 1- G 2. The expression for the main unit's fuel consumption rate (SFOC) is: , In the formula, P ME For the host output power, T ME This refers to the host's uptime.

[0028] Main unit output power P ME With respect to the amount of fuel burned ∆ G There is a complex relationship; under conditions of good fuel quality and combustion, an increase in ∆G within a certain range will lead to higher fuel consumption (ΔG). P ME Increase, but ∆G and P ME Both have minimum and maximum constraints, and there exists a minimum ratio of SFOC between them, which is a goal that has always been pursued in the field of engine manufacturing. SFOC reflects fuel quality, operating conditions, and engine performance. This invention achieves the SFOC minimization trend through composite feedforward cooperative control.

[0029] All three of the above-mentioned joint control modes are within the host security threshold. d MEWithin permissible limits, the system operates automatically. When manual control is selected, it operates in free mode. Even if the operator habitually changes one or both of the following parameters—ship speed, main engine speed, or pitch—the composite feedforward cooperative control system still functions, ensuring the propulsion system operates within its permissible operating range. Therefore, the goal of this invention's composite feedforward cooperative control is to achieve stable main engine performance and thermal balance, stable ship speed, and rapid response automatic control for safe and reliable ship maneuvering, preventing problems such as main engine overload, high exhaust temperature, black smoke, and large fluctuations in speed-pitch-throttle (control instability). It meets the requirements for stable main engine control in harsh sea conditions, control of acceleration and deceleration setpoints, handling time-varying disturbances, and minimizing the main engine SFOC trend under ocean navigation conditions.

[0030] When designing a ship, the maximum power output of the main engine operating continuously at rated speed under full load should be prioritized as the rated power. The optimal fuel consumption rate (SFOC) for the main engine is within the range of (75-80)% of the rated power. The actual output power of the main engine during operation should not exceed 95% of its maximum continuous power margin, and the main engine power margin should be limited to at least 5% of the rated power. On the other hand, the main engine overload is generally taken as 105% of the rated power, and continuous operation under overload is not permitted. The main engine is the source of power for ship navigation, and ensuring the safe operation of the main engine is one of the most important control objectives.

[0031] This invention utilizes a composite feedforward collaborative control strategy based on ship load inquiry function and controllable pitch propeller propulsion collaborative control to meet the optimal speed control requirements of ships under all operating conditions. Within the safe threshold allowable range of main engine power margin, it collaboratively controls the main engine speed and throttle, the hydraulic coupler output speed, and the controllable pitch propeller speed and pitch. It takes into account the inertia of ship navigation and main engine acceleration and deceleration processes, achieving the best ship speed control performance and stable thermal balance effect of the main engine. This enables automatic control with rapid response to ship maneuvering safety and reliability, preventing problems such as main engine overload, high exhaust temperature, black smoke, large fluctuations in speed-pitch-throttle (unstable control), and oil leakage from the controllable pitch propeller.

[0032] Furthermore, the present invention uses a hydraulic coupling to replace the reduction gearbox to buffer the impact of the propeller on the main engine, and is suitable for ship navigation in ice-covered areas.

[0033] Furthermore, this invention also proposes a composite feedforward cooperative control system for ship controllable pitch propeller propulsion, used to implement the above-mentioned composite feedforward cooperative control method, the system comprising: Data processing and modeling unit: used to store and run the controllable pitch propeller propulsion composite model, specifically performing the ship load query function, the ship speed closed-loop progressive control calculation, and the main engine safety threshold calculation; Data acquisition unit: used to acquire signals such as ship speed, main engine speed, main engine power, controllable pitch propeller pitch, throttle position and hydraulic coupler output speed in real time; Cooperative control decision unit: used to calculate power margin, determine host safety threshold and select cooperative control mode; The execution unit includes a main engine speed regulation and throttle actuator, a hydraulic coupler gear ratio control mechanism, and a pitch control propeller pitch hydraulic adjustment mechanism, which are communicatively connected to the collaborative control decision unit, and is used to execute the collaborative control commands.

[0034] The present invention also proposes a ship equipped with the aforementioned composite feedforward cooperative control system for ship controllable pitch propeller propulsion.

[0035] The closed-loop speed regulation, pitch control propeller pitch-main engine throttle linkage control, main engine speed-throttle linkage control, and pitch control propeller speed (hydraulic coupler output speed)-pitch linkage control of the present invention fill the gap in the field of optimal control of ships propelled by pitch propellers.

[0036] Compared with the prior art, the advantages of the present invention are: The proposed composite feedforward coordinated control method for ship controllable pitch propeller propulsion automatically switches between three coordinated control modes based on navigation conditions within the allowable safety threshold of the main engine. This achieves coordinated control of controllable pitch propeller pitch-main engine throttle linkage, main engine speed-throttle linkage, and controllable pitch propeller speed-pitch linkage under closed-loop stable control of ship speed. Under ocean navigation conditions, it automatically pursues the lowest fuel consumption; under adverse sea conditions, it maintains stable main engine power, ensuring safety. The application of hydraulic couplings is particularly suitable for navigation in ice-covered areas, buffering shocks and solving problems such as main engine overload, high exhaust temperature, black smoke, large fluctuations in speed-pitch-throttle (unstable control), frequent reciprocating adjustments, and oil leakage from the controllable pitch propeller.

[0037] This invention uses a ship load query function model to learn the relationship between main engine power and ship speed characteristics, and the relationship between controllable pitch propeller speed and ship speed characteristics. Based on EKF, it identifies the ship's resistance characteristics in real time, predicts the required main engine power and propeller speed at different ship speeds in advance, and calculates the power margin as the difference between the current main engine power and the maximum continuous power. The power margin limit value cannot be less than 5% of the rated power. It uses a safety threshold to trigger feedforward adjustment (adjusting the pitch in advance) to achieve composite feedforward control, preventing main engine overload and unstable speed. It eliminates the risk of main engine overload before it occurs and completely solves the persistent problems of accelerated black smoke emission and high exhaust temperature.

[0038] This invention uses a hydraulic coupling instead of a reduction gearbox to adapt to the complex operating conditions of ships sailing in ice-covered areas, eliminates the direct influence of the propeller on the main propulsion engine, and adjusts the speed of the controllable pitch propeller through the hydraulic coupling, making the coordinated control of speed, pitch and throttle more flexible, while maintaining the thermal balance of the main engine; the main engine of this invention is suitable for medium-speed and low-speed marine engines, and can burn methanol, ammonia or fuel oil in marine internal combustion engines.

[0039] This invention integrates the main engine, hydraulic coupler, and controllable pitch propeller into a whole for multi-variable coordinated control. By combining feedforward and feedback, it significantly reduces fluctuations in speed, pitch, and throttle, achieving smooth and precise speed control and improving speed control quality and system stability.

[0040] The controllable pitch propeller propulsion composite model established in the method of this invention is not only the core of the control algorithm, but can also be used for system status monitoring, performance evaluation and fault diagnosis, providing a platform for intelligent management of ship propulsion systems. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the principle framework of the controllable pitch propeller propulsion composite model in the system of this invention embodiment; Figure 2 This is a functional flowchart of the composite feedforward cooperative control system according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the composite feedforward cooperative control system according to an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the characteristics and limiting curves of the propulsion host in an embodiment of the present invention; Figure 5 This is a schematic diagram of the working characteristic curve of the hydraulic coupler in an embodiment of the present invention; Figure 6 This is a schematic diagram of the propulsion characteristic curve of the controllable pitch propeller in an embodiment of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be further described below.

[0043] See Figure 1-3 This embodiment proposes a composite feedforward cooperative control system for ship controllable pitch propeller propulsion, which includes the following core functional units that are interconnected: Data processing and modeling unit: used to run the controllable pitch propeller propulsion composite model. Specifically, it performs the following: 1) storing and calling the characteristic curves and constraint data of the six sub-models in the controllable pitch propeller propulsion composite model; 2) running the basic control algorithm based on the controllable pitch propeller propulsion composite model, which includes a speed control module. This module receives the target and feedback speed, performs closed-loop progressive PID control of the speed, and generates the initial main engine speed setpoint.

[0044] Data acquisition unit: Used to acquire signals such as ship speed, main engine speed, main engine power, controllable pitch propeller pitch, throttle position, and hydraulic coupler output speed in real time. It includes a voyage recorder (acquiring ship speed), a main shaft speed sensor (acquiring main engine speed and controllable pitch propeller shaft speed), a power meter (directly acquiring main engine power), a pitch feedback sensor (acquiring pitch), a throttle opening sensor (acquiring throttle scale / fuel injection quantity), a shaft power meter, and a torque meter (acquiring shaft power and shaft torque output from the hydraulic coupler). This unit is responsible for converting real-time physical signals into digital signals.

[0045] Collaborative control decision-making unit: corresponding to Figure 3 The system includes a composite feedforward cooperative control module and related logic selectors. This unit receives all information from the data processing and modeling unit and performs the following: power margin and safety threshold calculations; control mode selection: automatically or with manual confirmation, selecting one of three cooperative modes based on sea state, pilot instructions, and power margin; and generating cooperative instructions: operating according to the selected mode. Figure 3 The “speed selection” and “throttle selection” switches in the system integrate the output of the speed control module, the feedforward prediction of the load query model, and the safety protection logic to generate the final, coordinated throttle command, pitch command, and hydraulic coupling gear ratio command. The execution unit includes a main engine speed control and throttle actuator, a hydraulic coupler gear ratio control mechanism, and a controllable pitch propeller pitch hydraulic adjustment mechanism, all of which are communicatively connected to the aforementioned collaborative control decision unit. The main engine speed control and throttle actuator receives throttle commands from the collaborative control decision unit and drives the fuel rack or electronic fuel injection system. The hydraulic coupler gear ratio control mechanism receives gear ratio commands and adjusts the hydraulic coupler's working oil quantity to change the output speed. The controllable pitch propeller pitch hydraulic adjustment mechanism receives pitch commands and drives the distributor and the hydraulic piston within the propeller hub to change the pitch.

[0046] The working process of this composite feedforward cooperative control system is as follows: First, establish such Figure 1 The controllable pitch propeller propulsion composite model shown is a digital simulation system running on a control computer, integrating the following six sub-models: 1) Ship-engine-propeller relationship model: such as Figure 1 As shown, it includes the engine-propeller characteristic sub-model, the ship resistance characteristic sub-model, and the ship-propeller characteristic sub-model obtained through the new ship launch and sea trial experiments. The equations are as follows, and these equations provide physical constraints for the system dynamics.

[0047] The formula for the engine-propeller characteristic sub-model is: ; In the formula, J To increase the rotational inertia of the shaft system,n e For the main unit's rotation speed, n p For the controllable pitch propeller speed, M e For the main unit to output torque, M p For the torque of the controllable pitch propeller, M m This refers to the frictional torque of the shaft system. ; In the formula, P p For controllable pitch propeller power, P ME This refers to the output power of the main unit. or c For shaft transmission efficiency.

[0048] The formula for the ship resistance characteristic sub-model is: ; In the formula, R For ship resistance, α R The drag coefficient, v s For ship speed, m This is a ship index.

[0049] The formula for the ship-propeller characteristic sub-model is: ; In the formula, M For ship quality, v s For ship speed, T For the thrust of the controllable pitch propeller, ∑ T This indicates propulsion by two or more controllable pitch propellers. R For the resistance of the ship's motion; ; In the formula, P R To maximize the propulsion power of the controllable pitch propeller, or s For hull efficiency, or p To improve the efficiency of the controllable pitch propeller in flowing water, or x To improve the rotational efficiency of the controllable pitch propeller P p This refers to the power of the controllable pitch propeller.

[0050] 2) Propulsion main engine characteristics and limiting models: Stored propulsion modes including constant pitch FPP (Frequency Pilot Propulsion) and variable pitch CPP (Continuous Pitch Propulsion) modes, propulsion main engine speed characteristics obtained from main engine bench tests, propulsion main engine load characteristic curves, propulsion main engine limiting characteristics (including mechanical and thermal load limits, constant torque limits, and constant exhaust temperature limits), and boundary curves of the allowable operating range (e.g., ...). Figure 4 As shown in the figure, it defines the boundaries of host security operations.

[0051] Among them, the constant pitch FPP propulsion mode is a constant pitch control at a certain pitch, which enters the main engine speed and throttle coordinated control mode; the variable pitch CPP propulsion mode is a composite coordinated control mode of main engine speed-throttle-pitch; the main engine speed characteristics are obtained by constant throttle control at different throttle levels to obtain full load speed characteristics, overload speed characteristics, and partial load speed characteristics, and the torque curve of the main engine torque with speed change is obtained based on the main engine speed characteristics. The host load characteristics are obtained by constant speed control at different speeds to achieve the host's economic load, and the power curve is shown. When the load increases at a constant speed, the main engine power changes linearly; the allowable operating range of the main engine is the maximum and minimum power that the main engine can reach at various speeds, as well as the highest and lowest speed operating range that the main engine can reach under various loads; the main engine limiting characteristic curves include the constant torque limiting curve and the constant exhaust temperature limiting line, which are used to limit the main engine's over-mechanical load and over-thermal load, respectively; 3) Hydraulic Coupler Characteristic Model: This model converts the main engine's speed and torque into the controllable pitch propeller's speed and torque. It uses the hydraulic coupler's operating characteristic curves to show the relationship between the input / output speed and torque and the coupler's gear ratio. During hydraulic coupler engagement, the main engine torque, hydraulic coupler torque, and controllable pitch propeller torque are balanced. The model uses the hydraulic coupler's characteristic relationships to achieve optimal matching between the main engine's operating conditions and the controllable pitch propeller, preventing propeller overload or underload. It stores the input-output torque, speed, and transmission efficiency relationship curves obtained through hydraulic coupler bench tests (e.g., ...). Figure 5 The hydraulic coupler characteristic curve shown is used to precisely control the speed ratio of the hydraulic coupler.

[0052] 4) Controlled-pitch propeller characteristic model: including controlled-pitch propeller torque sub-model, controlled-pitch propeller thrust sub-model, controlled-pitch propeller power sub-model, and controlled-pitch propeller flow efficiency sub-model; such as Figure 6 As shown, it stores the propeller characteristic curves obtained from the controllable pitch propeller water flow experiment.

[0053] The formula for the controllable pitch propeller torque sub-model is as follows: , In the formula, M p For controllable pitch propeller torque,K M This is the torque coefficient of the controllable pitch propeller. r The mass density of water, D The diameter of the controllable pitch propeller. n p This refers to the controllable pitch propeller speed; The formula for the controllable pitch propeller thrust sub-model is: , In the formula, T For controllable pitch propeller thrust, K T This is the thrust coefficient of the controllable pitch propeller. D The diameter of the controllable pitch propeller. n p This refers to the controllable pitch propeller speed; The formula for the controllable pitch propeller power sub-model is: , In the formula, P p For controllable pitch propeller power, K M This is the torque coefficient of the controllable pitch propeller. r The mass density of water, D The diameter of the controllable pitch propeller. n p This refers to the controllable pitch propeller speed; The formula for the flow efficiency sub-model of the controllable pitch propeller is: , In the formula, or p To improve the efficiency of the controllable pitch propeller in flowing water, T For controllable pitch propeller thrust, v p For controllable pitch propeller advance speed, n p For the controllable pitch propeller speed, D The diameter of the controllable pitch propeller. M p This refers to the torque of the controllable pitch propeller.

[0054] 5) Ship Load Inquiry Model: This is the core model used to collect sensor data in real time. It identifies the ship's drag coefficient online by analyzing the relationships between ship speed and main engine power, and between ship speed and propeller speed. Using the identification results and the aforementioned physical model, two mapping relationships are dynamically constructed through ship design and sea trials: the main engine power-ship speed relationship (i.e., the first mapping relationship between ship speed and main engine power) and the controllable pitch propeller speed-ship speed relationship (i.e., the second mapping relationship between ship speed and propeller speed), along with the allowable continuous operating range boundaries.

[0055] 6) Controlled pitch propeller propulsion coordinated control model: used to receive the prediction results of the load query model, the pilot's instructions and system feedback, establish coordinated control between main engine speed and throttle, hydraulic coupler output speed and controlled pitch propeller speed and pitch, and calculate and output coordinated control commands.

[0056] In this embodiment: the engine-propeller characteristics, drag characteristics, ship-propeller characteristic curves and numerical models, controllable pitch propeller characteristic curves and numerical models, and ship-engine propulsion characteristic curves and numerical models are obtained through new ship launch and sea trial experiments; the propulsion main engine speed characteristics, load characteristics, limiting characteristics, and allowable operating range boundary curves are obtained through main engine bench experiments; the hydraulic coupler characteristic curves are obtained through hydraulic coupler bench experiments; the propeller characteristic curves are obtained through controllable pitch propeller run-through experiments; and the ship design and sea trial corrections are used to obtain the correspondence curves between ship speed and main engine power and the allowable continuous operating range boundary. The above characteristic curves reflect the ideal design characteristics of the ship-engine-propeller propulsion system. The above characteristic curves are not just a few lines as shown in the figure, but a cluster of countless continuous curves.

[0057] During ship operation, data is automatically collected and the predicted values ​​and curves of the above characteristics are identified by the data-driven extended Kalman filter (EKF) online adaptive prediction algorithm. The degree to which these predicted curves deviate from the design characteristic curves indicates the changes in ship propulsion performance and operating conditions, which are then fed back to the controllable pitch propulsion composite model.

[0058] When the helmsman pushes the ship's control lever to change the ship's speed setpoint, the navigation data recorder feeds back the actual speed, resulting in a speed deviation. This speed deviation is processed by the ship speed closed-loop progressive PID control loop and then input to the ship load query function model. Based on numerical models of the main engine power-ship speed characteristic relationship and the controllable pitch propeller speed-ship speed characteristic relationship, the ship load query function model automatically identifies the ship's resistance characteristics using data-driven EKF, predicts the required main engine power and propeller speed at different ship speeds, calculates the difference between the current main engine power and the maximum continuous power as the current power margin, and determines the maximum continuous power margin Δ of the main engine. P max The power margin limit is set to be no less than 5% of the rated power, and the main engine safety threshold is determined to be 95% of the maximum continuous power margin. This is fed back to the main engine characteristics and limitation model in advance to prevent main engine overload during acceleration and a sudden increase in main engine speed during deceleration. During this process, if the ship load query function model predicts the additional main engine power ΔP required to reach the target speed... ME Greater than the host security threshold d ME If the throttle command is increased, the composite feedforward cooperative control model module commands the pitch to be reduced in advance, sacrificing some instantaneous acceleration in exchange for the absolute safety of the main unit, and then continuing normal acceleration after the power margin is restored.

[0059] In this embodiment, the controllable pitch propeller propulsion coordinated control model includes a main engine constant speed pitch-throttle joint control mode under closed-loop speed stability control, a controllable pitch propeller constant pitch speed-throttle joint control mode, and a controllable pitch propeller speed-pitch joint control mode under constant main engine power (constant throttle). The manual control mode is selected as a free combination of main engine speed-throttle and propeller speed-pitch, all of which can achieve closed-loop automatic control of ship speed. The specific functional implementation process is as follows: Figure 2 As shown.

[0060] Figure 2 The diagram shows the specific operational function of the composite feedforward coordinated control system for ship controllable pitch propellers: The pilot operates the ship speed control lever to obtain the ship speed setpoint. V s * The actual speed of the ship, as measured by the navigation recorder, was: V s Obtain the speed deviation ∆ V s = V s * - V s The deviation ∆ V s The speed is processed by a closed-loop progressive PID control loop. The processing method is as follows: according to a certain adjustment interval ∆ t and amplitude d (∆ t Output speed control commands, i.e. Instead of adjusting the pitch abruptly all at once, this prevents impact on the main engine, hydraulic coupling, and controllable pitch propeller. V s → V s * The process must consider the ship's acceleration and deceleration inertia. The ship's speed adjustment inertia differs significantly under conditions such as heavy load / empty load, headwind / tailwind, etc. This can be addressed by adjusting ∆... t and d (∆ t This ensures that the acceleration and deceleration processes are adapted to the ship's inertia. The advantage of progressive PID control is that it does not directly respond to step changes in the speed setpoint, but rather allows the input given speed command signal to gradually approach the required setpoint step signal, resulting in smoother ship operation. The obtained speed control command is input to the ship load query function model. In existing technologies, the "speed control command" generally acts directly on the main engine. The innovation of this invention is that the speed control command obtained after processing through the ship speed closed-loop progressive PID control loop is first passed through the ship load query function model to calculate Δ... V sRequired main engine power ΔP ME And power margin limit value, output progressive value d (∆ t ) corresponding main engine power and not exceeding the allowable power margin range of the main engine.

[0061] Ship resistance includes frictional resistance, wave-making resistance, viscous pressure resistance, appendage resistance, and resistance generated by wind, waves, and currents. These resistances cannot be directly measured and the EKF algorithm needs to be driven by the data of actual ship navigation to identify and predict the resistance. Traditional ship resistance prediction methods mostly rely on trial voyage data or offline fitting models, and it is difficult to adapt to complex and changing navigation conditions. The present invention uses measurable ship signals (such as ship speed, propeller speed, shaft power, etc.) to achieve the identification of navigation resistance. The process of ship resistance characteristic identification is as follows: 1) Collect the operation data of ship navigation-related parameters through the existing monitoring and alarm system of the ship in a communication manner. These data sets include directly available data such as main engine fuel consumption, main engine speed, main engine power, ship speed, propeller shaft torque, propeller speed and pitch, slip ratio, etc.; 2) Perform preprocessing on these data, synchronize and reconstruct the data to solve the problems of different data frequencies, abnormal or missing values, and inconsistent time, and clean the abnormal data caused by sensor abnormalities, propulsion system failures, etc. At the same time, considering that weather conditions, sea conditions, loading conditions, hull and propeller cleanliness, etc. all affect ship speed, main engine load, etc., and it is difficult to accurately evaluate the impacts of weather conditions, sea conditions, and hull fouling conditions, etc., it is necessary to identify the changes in ship resistance characteristics and apply them to the compound feedforward control of the present invention; 3) The present invention is based on the ship-propeller characteristic sub-model , propeller thrust T p and rotational speed n p relationship model , where g T is the thrust synthesis coefficient to be identified, g T synthesizes factors such as wake fraction coefficient, water density ρ, propeller diameter D, propulsion efficiency, etc., and can be used as a state to be identified by EKF, avoiding the dependence on K T , K Q charts. Ship navigation resistance empirical model , a 1, a 2, a 3 are coefficients to be identified; v s , a 1, a 2, a [[ID=4⑧]]3 and g T are defined as the state vector Discretized coefficient state transition equations, speed models, and drag observation models are established by inputting measurable propeller speeds. n p (k) and speed v s (k) From the drag observation model, the drag coefficient estimate can be obtained. , , and estimated speed Thrust coefficient and resistance estimates Using resistance identification Get current speed v s Lower effective power estimation ,Stablize v s Thrust of navigation Further identification of the speed v s Overall propulsion efficiency ( P p (for the measured shaft power), total propulsion efficiency or D The typical range is 0.55–0.75, and the identification value is... Compared to the original value or D A large number indicates sailing with the wind and current, while a small number suggests sailing against the wind and current or that the ship is dirty; and or D The difference is used to quantify the change in the ship's navigation resistance characteristic curve, obtain the assessment results of the changes in ship status and navigation conditions, and send them to the collaborative control decision unit.

[0062] The ship's sea trials must meet the following conditions: clean hull and propeller, deep open water (depth > 100 meters), no wind, no waves, and no currents. The main engine power (P) must be obtained through the sea trials. ME ) ~ Boat speed (v s ) curve, propeller speed (n p ) ~ Main unit power (P ME ) curve, propeller speed (n p Ship speed (v) s The curves of the main engine-hydraulic coupler-controllable propeller propulsion system, especially the propeller torque (M) curves. p ) ~ Rotational speed (n pThese curves, such as the main engine power-ship speed curve, are stored in the computer to build a numerical model, serving as a characteristic reference for ship operation. By comparing the measured main engine power-ship speed curve with the trial curve, the difference in main engine power at the same speed can be obtained. If the measured power corresponding to the same speed value is greater than the power during the trial, it indicates headwind or headcurrent or hull fouling; if it is smaller, it indicates sailing with the wind and current, which is consistent with the resistance identification results and is also sent to the collaborative control decision unit.

[0063] The load query model outputs a data packet (predicting the required main engine power and the optimal controllable pitch propeller speed, current power margin Δ). P * , d ME ), and together with the progressive speed control command, it is sent to the cooperative control decision unit, that is Figure 3 The decision layer shown, which includes the "load feedforward collaborative control module," "selector," and "host speed setting limit circuit," executes the following steps: Step 1: Safety Threshold Judgment—The decision unit calculates the increase in host power demand and determines the power demand increase ΔP. ME Is it greater than the host security threshold? d ME If not, the verification passes; if yes, the feedforward protection mechanism is triggered.

[0064] Step 2: Control Mode Selection—Based on the current sea conditions, the system automatically selects the control mode. In this embodiment, the relationship between ship resistance characteristics, ship speed and main engine power, and propeller speed is obtained through a data-driven EKF online adaptive prediction algorithm. The correlation between these relationships is verified to be valid if it is above 0.95. The following control modes are then selected using the controllable pitch propeller coordinated control model: Mode 1: When controlling ship speed in main engine constant speed mode, under ocean navigation conditions, the pitch is a constant value based on the main engine speed. H p Position loop servo control, coordinated with main engine throttle L Tracking pitch propeller H p The adjustment, throttle-pitch coordinated control model is as follows: , , In the formula, L For the main engine throttle, H p For the pitch of the controllable propeller, v s For the ship's speed, n p This refers to the controllable pitch propeller speed.

[0065] At host security threshold dME Within permissible limits, when the ship accelerates under constant engine speed mode, the composite feedforward collaborative control synchronously increases the pitch-throttle; when the ship decelerates, the composite feedforward collaborative control synchronously decreases the pitch-throttle, realizing pitch-throttle linkage control. The lead time of the composite feedforward collaborative control is less than the inertial time of the ship's propulsion system.

[0066] Due to factors such as shipboard fouling, propeller blade deformation, wind, waves, and currents, the throttle-pitch relationship is complex and time-varying. L = P ( H p The experimental numerical curves obtained from the sea trials of a new ship can be used to obtain continuous values ​​through polynomial interpolation during actual operation. The constant engine speed control mode controls the ship's speed by adjusting the propeller pitch. This offers superior performance compared to conventional ship speed control via propeller speed adjustment, achieving the lowest possible SFOC (Speed, Load, and Oxide) at this constant speed. The pitch-throttle linkage aims to control the ship's speed at a constant engine speed while preventing overloading, thus avoiding problems such as large fluctuations in speed-pitch-throttle, black smoke from the main engine, and high exhaust temperatures.

[0067] Meanwhile, under stable operating conditions during ocean navigation, the ship's speed is stable, and the system automatically selects the lowest SFOC control. The lowest SFOC operating range is determined by the SFOC-main engine power polynomial curve interpolation method, and energy-saving optimization control is achieved by adjusting the throttle and pitch in a coordinated manner to ensure that both the ship's speed and the main engine speed are stable.

[0068] Mode 2: When controlling ship speed in the controllable pitch propeller constant pitch mode, the main engine speed is controlled in a closed loop with the controllable pitch propeller pitch as a constant value. This is coordinated with the main engine throttle to track and adjust the main engine speed accordingly. The main engine speed-throttle coordinated control model is as follows: , In the formula, K p , K I and K d These are the adjustable proportional coefficient, integral coefficient, and differential coefficient, respectively. n e For the main engine speed deviation, e To dynamically compensate for and control the uncertainties, this invention employs a deep learning algorithm to obtain... e Compensation value.

[0069] At host security threshold d ME Within permissible limits, during ship acceleration in constant pitch mode, the composite feedforward cooperative control synchronously increases the main engine speed. n e and throttle LWhen the ship decelerates, the composite feedforward coordinated control synchronously reduces the main engine throttle and main engine speed, achieving main engine speed-throttle linkage control. The lead time of the composite feedforward coordinated control is less than the inertia time of the ship's propulsion system. Changes in throttle L affect the main engine speed and power. Throttle adjustment is the actuator of the governor, meaning that main engine speed control is achieved through throttle control. Therefore, in the initial stage of main engine speed-throttle linkage control, the given throttle output by the governor and the feedforward action throttle work together, and it is only effective after being limited by the main engine load. This invention differs from conventional main engine speed-throttle adjustment systems where the throttle passively follows the governor output for adjustment. The main engine speed-throttle linkage control aims at constant pitch speed control. In the initial stage of control, the main engine speed and throttle are adjusted synchronously at the same time. Then, a cascade control is implemented with throttle adjustment as the inner loop and main engine speed adjustment as the outer loop. The feedforward throttle decays to the level of the governor throttle, with the main engine not overloaded as the limitation, preventing problems such as large speed-throttle fluctuations, black smoke from the main engine, and high exhaust temperature.

[0070] Mode 3: When controlling ship speed in main engine constant power (constant throttle) mode, i.e., the controllable pitch propeller speed (hydraulic coupler output speed) - pitch coordinated control mode, it is suitable for ship navigation in harsh sea conditions. The controllable pitch propeller speed - pitch coordinated control is based on the main engine throttle scale (fuel injection quantity) as a constant value. Its control objective is to maintain the thermal balance of the main engine. The controllable pitch propeller speed - pitch coordinated control under main engine constant power is as follows: , , , In the formula, P ME This refers to the output power of the main unit. K o For the controllable pitch propeller propulsion coefficient, C(H p / D) For controllable pitch propeller thrust, v s For ship speed, L This refers to the engine throttle (fuel injection quantity). n p For the controllable pitch propeller speed, H p For the pitch of the controllable propeller, or o To improve efficiency, S For slippage rate, K G It is the adjustable ratio of the variable speed hydraulic coupling.

[0071] When the main engine throttle controller keeps the throttle constant, the main engine speed cannot remain constant. The required speed for the controllable pitch propeller is then output through the hydraulic coupling. n pSimultaneously adjusted via pitch controller H p The prerequisite for coordinated control of controllable propeller speed and pitch is the main engine power. P ME Constant throttle position L To achieve a constant throttle value and maintain the thermal balance of the main engine, the ship's speed is controlled under constant main engine power. During ship speed control, sea state disturbances can cause the ship's speed to deviate from the pilot's set speed. For example, when facing headwinds or currents, the ship's speed decreases. The composite feedforward control reduces the propeller pitch while adjusting the output speed of the hydraulic coupler. When sailing with the wind or current, the ship's speed increases. The composite feedforward control increases the output speed of the hydraulic coupler while adjusting the propeller pitch to maintain a constant main engine power, but the speed increases. Alternatively, the composite feedforward control reduces the output speed of the hydraulic coupler and the pitch of the controllable pitch propeller to reduce the main engine power and maintain a constant speed. The composite feedforward control synchronously adjusts the controllable pitch propeller speed-pitch, stabilizing the ship's main engine performance under adverse sea conditions, maintaining the thermal balance of the main engine, and preventing problems such as black smoke and high exhaust temperatures. The innovation of this invention's constant throttle control lies in adjusting the propeller speed through the hydraulic coupler to maintain a stable main engine speed under this constant throttle.

[0072] All three of the above-mentioned joint control modes are within the host security threshold. d ME Within permissible limits, the goal of composite feedforward collaborative control is to achieve automatic control that ensures stable main engine performance and thermal balance, stable ship speed, and rapid response in ship maneuvering safety and reliability. It aims to prevent problems such as main engine overload, high exhaust temperature, black smoke, and large fluctuations in speed-pitch-throttle (unstable control). It satisfies the requirements of main engine stability control during ship navigation in adverse sea conditions, control of acceleration and deceleration setpoints, and time-varying disturbance conditions, as well as the trend of minimizing main engine SFOC under stable ocean navigation conditions.

[0073] Step 3: Multi-signal collaborative synthesis, such as Figure 3 As shown, this is the control principle of the controllable pitch propeller propulsion composite feedforward cooperative control system: First, the ship's speed is detected by the voyage recorder. V s Two sets of non-contact magnetic pulse sensors detect the main engine output speed and the controllable propeller shaft speed (hydraulic coupler output speed) respectively; the pitch Hp / propeller angle θ is detected by the displacement of the dual oil pipes inside the distribution shaft, and the position sensor (pitch feedback sensor) detects the displacement ζ of the dual oil pipes and converts it into pitch. H p (ζ) / propeller angle θ(ζ), ζ has a strict geometric relationship with pitch Hp / propeller angle θ; throttle displacement (opening) sensor detects throttle position L, each throttle position L corresponds to a different fuel injection quantity; shaft power meter detects shaft power output by hydraulic coupler; these key signals are fed back to speed control module and composite feedforward cooperative control module respectively.

[0074] Path A (Speed ​​Main Loop): The speed control module will set the given speed (ship speed setpoint). V s * And feedback speed (actual speed of the ship) V s Speed ​​deviation ∆ V s The speed of the ship based on the load query model ( v S )∽Main unit power ( P ME The relationship is converted into host power demand and host power setpoint. P ME * , P ME * Converted into the host speed setpoint by the host speed generator n * ME The host speed setting value is determined by the host speed setting limit circuit (such as...). Figure 4 After setting the host's minimum / maximum speed limit, critical speed limit, acceleration rate limit, and program load limit, a valid host set speed is generated. n * e , n * e With host speed feedback value n e The speed deviation ∆ is obtained by comparison. n e , ∆ n e The throttle control setpoint of the main unit is output after calculation by the PID+ intelligent algorithm of the speed governor. L 1 * .

[0075] Path B (Throttle Feedforward): Simultaneously, a feedforward throttle command is generated based on the collaborative logic of the selected control module. L 2 * (For example: pitch-throttle linkage, the system is based on the current pitch) H p (or target pitch) and calibration function L = P ( H p A feedforward throttle command is generated directly. L 2 * ).

[0076] Path C (Speed ​​Feedforward): The ship's speed is queried from the model based on the ship's load. vS - Propeller speed ( n p The relationship is converted into a controllable pitch propeller speed demand command, which is then applied to the hydraulic coupler via the speed ratio controller to adjust the propeller shaft speed output by the hydraulic coupler, thereby meeting the ship's speed requirements and achieving optimal ship-propeller matching.

[0077] Generate final throttle command L * , L * Throttle feedback L Compared to obtain the throttle deviation ∆ L , ∆ L The throttle controller obtains the throttle opening value (fuel injection quantity) and sends this final throttle opening value to the "main engine load limiting module" to limit the fuel injection quantity and prevent excessive mechanical and thermal loads. The limited final fuel injection quantity command is then sent to the throttle actuator (servo follower mechanism).

[0078] The implementing agency will take the following actions: The main engine throttle actuator performs the final command after being restricted.

[0079] The pitch control hydraulic unit operates according to the calculated target pitch (from Hp=λ(v)). s / n p D) Determine the action.

[0080] The hydraulic coupling adjusts the speed ratio according to the command, so that the output shaft speed approaches the target speed of the controllable pitch propeller.

[0081] When the ship begins to accelerate, the data acquisition unit ( Figure 3 Sensors throughout the ship collect real-time data on ship speed, main engine parameters, etc., and feed this data back to the system input, forming a closed loop. The load query model continuously identifies and updates predictions online. Throughout the process, the ship speed increases smoothly, and the main engine load remains constant. Figure 4 Within the indicated safe area, there is no overshoot or black smoke.

[0082] In this embodiment, the above three control modes are achieved through a combination of main engine speed and throttle, adjustment of hydraulic coupler output speed, and propeller pitch adjustment. These modes are processed simultaneously by the main engine control and limiting module, hydraulic coupler control module, and controllable pitch propeller control module, and act simultaneously on the main engine governor and throttle controller, hydraulic coupler gear ratio control, and controllable pitch propeller pitch adjustment hydraulic system. They are coordinated and controlled according to the rules required by the control modes. The controllable pitch propeller acts on the ship to change the ship's speed. The ship's resistance characteristics are identified and the required propulsion power and speed are fed back to the ship load query function module. The module calculates in a timely manner the main engine power, propeller speed, and main engine power margin limit (not less than 5% of rated power) required to maintain the ship speed. The ship's closed-loop progressive control module slightly changes the speed control command to ensure that the ship's speed control process is smooth and the propulsion system is not impacted.

[0083] In this embodiment, the load feedforward cooperative control module controls the "speed selection" and "throttle selection" through the throttle "selector"; when "speed selection" is "1", L 1 * Valid when it is "0" L 1 * It does not work; when "Throttle Selection" is "1" L 2 * Valid when it is "0" L 2 * It doesn't work If the load feedforward collaborative control module selects the constant power mode propeller speed-pitch linkage control, then "Speed ​​Selection" is "0", and the control command output by the governor is given by the throttle. L 1 * It doesn't work; "Throttle Selection" is "1". L 2 * If it works, then ∆ L = L 2 * - L The throttle controller makes ∆ L =0, L 2 * = L , L It is a constant value unless a value is given. L 2 *The invention addresses the issue of propeller speed variation in constant power mode, where the main engine speed changes with load, although the main engine speed limiter still functions. By adjusting the gear ratio of the hydraulic coupling to regulate the propeller shaft speed, the invention adapts to different propeller pitches. This means the product of propeller speed and torque variation caused by pitch adjustment remains constant, facilitating speed control in harsh sea conditions and achieving stable thermal balance for the main engine. This prevents problems such as overload, unstable combustion, frequent throttle changes, and large speed fluctuations. The innovation lies in the coordinated control of propeller speed and pitch (a relationship exists between thrust and pitch) to stabilize ship speed and main engine load, improving navigation safety and reliability in harsh sea conditions. Furthermore, in harsh sea conditions, the hydraulic coupling can rapidly reduce the output speed when the propeller leaves the water, preventing main engine runaway.

[0084] If the load feedforward collaborative control module selects the constant pitch control mode for main engine speed-throttle linkage, then both "Speed ​​Selection" and "Throttle Selection" are "1". L 2 * and L 1 * Both work, ∆ L =( L 1 * + L 2 * )- L Main engine speed and throttle are controlled in tandem; ship speed control under constant pitch is achieved through main engine speed control. During ship acceleration and deceleration, the required power for propulsion is generated. L 2 * Throttle command, at the same time L 1 * The speed is generated by the governor based on the required main engine speed of the ship. L 1 * Throttle setpoint, ( L 1 * + L 2 * It acts on the throttle and is limited by the main engine load, but the throttle feedforward... L 2 * Finally disappeared L 1 * Based on this, L 2 * → L 1 * The process is the process by which the actual ship speed rapidly approaches the given ship speed. L 2 * It depends only on the rate of change of the given ship speed. L 2 *The feedforward action accelerates speed regulation; during the speed setpoint maintenance, cascade control is implemented with throttle regulation as the inner loop and main engine speed regulation as the outer loop. When the helmsman increases the ship's speed, the ship load inquiry module generates the required propulsion main engine power for the speed increase, which is then output via the load feedforward cooperative control module. L 2 * The increased value acts on the throttle controller to increase the throttle; simultaneously, the increased main engine speed required for the ship's speed increase generates a throttle command via the governor. L 1 * It also acts on the throttle controller to increase the throttle. L 1 * + L 2 * After being limited by the main engine load, the throttle feedforward is applied to the throttle actuator. L 2 * Finally disappeared L 1 * Based on this, load limits include maximum injection quantity (throttle) limit, minimum injection quantity (throttle) limit, boost air pressure limit, maximum torque limit, and exhaust gas temperature limit. The throttle actuator selects the effective throttle command after the load limit is applied. Therefore, ( L 1 * + L 2 * The action applied to the throttle controller will not cause the main engine to overload. When the ship is sailing against the wind and current, the main engine governor output... L 1 * If only the main engine speed governor is activated, it will cause the main engine to overload. In this case, the ship load inquiry function module will identify a sudden increase in power at a certain ship speed, and then output... L 2 * A negative value indicates suppression. L 1 * Excessive power can overload the main engine; when the ship is with the wind and current, L 1 * The power will decrease. At this point, the ship load query module will detect a sudden decrease in power at a certain ship speed and then output... L 2 * The actual speed is 0, which means the boat speed is greater than the set speed, thus achieving the effect of faster speed and lower fuel consumption, or output... L 2 * If the value is negative, the throttle is further reduced to maintain the boat speed at the given speed.

[0085] If the load feedforward collaborative control module selects the pitch-throttle linkage control in the main engine constant speed mode, then both "Speed ​​Selection" and "Throttle Selection" are set to "1". L 2 * and L 1 * Both work, ∆L =( L 1 * + L 2 * )- L When the ship accelerates, the propeller pitch increases, and the load feedforward coordinated control module adjusts the load based on the increase in pitch ( L = P ( H p Output positive throttle feedforward command L 2 * To prevent the main unit speed from dropping too much, at this time L 2 * Related to the rate of change of the controllable propeller pitch setpoint; when the ship speed deviation is close to 0, ( L 1 * + L 2 * → Increased output of the speed controller L 1 * As ship speed and thrust increase, the main engine speed remains constant. Similarly, when the ship decelerates, the propeller pitch decreases, and the load feedforward coordinated control module adjusts its response based on the decrease in pitch ( L = P ( H p Output negative throttle feedforward command L 2 * To prevent the main engine from overspeeding; when the ship's speed deviation is close to 0, ( L 1 * + L 2 * → The speed controller output decreases L 1 * During the process of ship speed and thrust reduction, the main engine speed remains unchanged.

[0086] The above three control modes must operate within the range allowed by the host computer. Figure 4 The figure shows the host characteristics and limiting curves to ensure stable, reliable, and economical operation of the propulsion host. The horizontal axis represents the percentage of the propulsion host's rotational speed. n e / n eN )% ， The vertical axis represents the percentage of propulsion power ( P e / P eN )%, where curve 1 is the constant exhaust temperature limiting characteristic line, curve 2 is the full load speed characteristic line, curve 3 is the full load constant torque limiting characteristic line, curve 4 is the overload speed limiting characteristic line, curve 5 is the rated throttle opening (rated fuel injection quantity) speed regulation characteristic line, and curve 6 is the overload (110%) characteristic line. PeN Speed ​​regulation limit characteristic curve, curve 7 represents the rated speed of the main unit. n eN Characteristic curves: Curve 8 is the minimum load speed limit characteristic curve, Curve 9 is the minimum stable speed limit characteristic curve, Curve 10 is the minimum speed characteristic curve for long-term continuous operation of the main engine, and Curve 11 is the propeller propulsion characteristic curve; (The rest of the text appears to be a list of curves and their characteristics.) Figure 4 It is known that the main engine can operate safely and continuously within the boundary area enclosed by 3-1-10-8-5-3, where MCR represents the main engine's maximum continuous power operation. Ships rarely operate at 100% MCR, but mostly at around 80% MCR. This invention uses load feedforward control of pitch, shaft speed, and throttle to adapt the main engine to different sea conditions and operating conditions, allowing the main engine to operate in a low-fuel-consumption operating range.

[0087] In conventional ships, propeller shaft speed is controlled by regulating the main engine speed, which limits the optimization of main engine performance. This invention utilizes a hydraulic coupling to adjust the shaft speed, improving the ship-engine-propeller coordination characteristics. Figure 5 The figure shows two external characteristic curves of the hydraulic coupling, with the horizontal axis representing the rotational speed. n e The vertical axis represents torque. M e Gear ratio i = b 1, b 2, b 3… refers to the input-output speed ratio, also known as transmission efficiency; the hydraulic coupling transmits torque. M With rotational speed n The change between them follows a quadratic law, that is... M = f ( n 2 The function, where the transmission efficiency of the hydraulic coupler is a certain constant. i Hydraulic coupling input speed n For a certain constant a ,Right now n 1, n 2, n 3 …= a 1, a 2, a When 3…, M-( n 输出 / n 输入 Let be an elliptic curve, and let be the intersection point of the elliptic curve and the isoefficiency curve. P 1, P 2, P 3 … indicates that the hydraulic coupling adapts to changes in the output speed by varying the input speed of the main unit, and its transmission efficiency is… iLet b be a constant. The purpose of selecting a hydraulic coupling in this invention is to meet the requirements of ship navigation in ice-covered areas, providing flexible transmission, no torque conversion capability (equal torques on the driving and driven shafts), and achieving buffering and vibration reduction.

[0088] Figure 6 For the characteristic curve of a controllable pitch propeller, the main geometric parameters of the propeller, such as the diameter D, pitch ratio H / D, and blade area ratio, have a significant impact on its propulsive performance, with the diameter D having the greatest influence. For a propeller with a fixed diameter D, the larger its pitch H and blade spread area, the greater the thrust it generates, and the greater the torque and power it absorbs. The thrust and efficiency of a controllable pitch propeller depend not only on the advance coefficient but also on the pitch ratio H / D. When the ship's resistance remains constant, the characteristic curve changes with each adjustment of the pitch; the larger the H / D, the steeper the characteristic curve. Figure 6 As observed, the effect of H / D on the characteristic shape of controllable pitch propellers is similar to the effect of ship resistance on the characteristic shape of fixed pitch propellers. When the pitch remains constant, it reflects the characteristics under a certain ship resistance. When the ship resistance condition remains constant, changing the pitch can obtain the same characteristics. Therefore, when the ship resistance condition changes, the characteristics can be kept constant by changing the pitch, thus achieving propulsion system stability.

[0089] Therefore, the composite feedforward cooperative control system of the ship controllable pitch propeller propulsion in this embodiment can predict the main engine power margin in real time and change the ship-engine-propeller matching control characteristics in advance, effectively reducing system overshoot and enabling the main engine to operate stably under the premise of being below the speed-load limit line.

[0090] Example 2: Resistance Identification Method in Load Inquiry Model This embodiment 2 supplements the "resistance characteristic identification" in embodiment 1 with a specific algorithmic approach. The following specific method can be used to identify resistance through load querying the model: This invention proposes an EKF adaptive prediction algorithm that is independent of K-axis resistance, using online data-driven prediction of ship navigation resistance to learn from ship navigation data online. T K Q The online identification method for the map uses only speed and propeller speed to estimate drag and its parameters in real time. The steps are as follows: Based on the ship-propeller characteristic sub-model propeller thrust T p With rotational speed n p relational model Empirical models of ship navigation resistance Define the EKF state vector Then the 5 states are x 1= v s , x 2=a 1. x 3= a 2. x 4= a 3. x 5= x T Establish the discretized state equations: ,in T s The sampling period; sampling T s The coefficients change slowly over a short period of time; the discretized coefficient state equation is as follows: a 1( k +1)= a 1( k ), a 2( k +1)= a 2( k ), a 3( k +1)= a 3( k ), x T ( k +1)= x T ( k ); The nonlinear state transition function is ,in w ( k ) represents process noise. f (·) is the state transition function from time k to time k+1, that is: , , , , , Then, the state transition function is , Establish observation model for ,in y ( k ( ) represents the speed measurement at time k. v ( k For measurement noise, the nonlinear observation function that maps the state to the speed. , v s ( k () represents the estimated speed at time k; f (·)and h (·) Perform local linearization on the first-order Taylor expansion near x to obtain f (·) The state transition Jacobian matrix Ω is linearly approximated near the current estimated point. h (·) The observed Jacobian matrix H, which is a linear approximation near the current prediction point, is a partial derivative matrix with respect to the state x.

[0091] The input for EKF to identify ship drag is the measured propeller speed. n p ( k ) and speed y ( k The output is an estimated value. , , , , and Therefore, the steps for identifying ship resistance characteristics based on EKF are as follows: Step 1: Initialization (k=0), setting initial state estimates And the observed covariance matrix P(0); Step 2: Prediction Iteration ,in Let k be the prior state prediction value at time k. Let k be the posterior state estimate at time k-1; Predict covariance, ,in Let be the prior error covariance matrix. P ( k -1) represents the error covariance after the previous update, Ω( k -1) is the state Jacobian matrix. Q The process noise covariance matrix; Step 3: Calculate the Kalman gain Where H is the observation Jacobian matrix and Γ is the observation noise covariance matrix; Status Update: , where y(k) is the measured speed at time k. To predict speed; Covariance update: Where I is the identity matrix, P ( k Let be the posterior error covariance matrix at time k; Step 4: Estimate the resistance as , Based on the current estimated drag coefficient , , Current speed can be estimated v s resistance below Thus, the drag characteristics are obtained; The coefficient remains approximately constant within a short time window, allowing for prediction of drag at future speeds. When the pilot changes the speed setpoint... v s * At that time, v s * The predicted resistance is Using predictive resistance Achieve the final target speed v s * Required effective power ,maintain v s * Thrust required for stability ,but v s * The required propeller speed is This allows for the prediction of future speeds. v s * Required propulsion power (Overall progress efficiency) From the current speed v s (estimated) and propeller speed n p * Simultaneously calculate the predicted host power and maximum continuous power. P emax The difference is used to obtain the predicted power margin Δ. P * And according to the formula Calculate the host security threshold d * ME Predicted value.

[0092] Example 3: Detailed Logic of Safety Threshold Triggering and "Advanced Pitch Reduction" Protection Mechanism Triggering condition: When the collaborative control decision unit determines that the power ΔP should be increased. ME Host security threshold d ME It will be triggered immediately.

[0093] Protection action: The composite feedforward collaborative control module immediately outputs a negative "emergency pitch correction amount". This correction amount is directly added to the normal pitch. Above, the actual pitch command executed becomes .

[0094] Action effect: Based on the controllable pitch propeller thrust sub-model, pitch The reduction will directly lead to the thrust coefficient K T The speed decreases, thus reducing the controllable propeller speed. n p Instantly reduce thrust T and controllable propeller torque without changing the thrust T and controllable propeller torque M p This actively "flattens" the host load demand curve, ensuring that even with acceleration inertia, the actual peak power will not exceed [a certain threshold]. d ME This will prevent overloading.

[0095] Recovery logic: The system continuously monitors the power margin. Once the current power margin recovers to a safe level, an emergency correction is initiated. Gradually reset to zero, the system resumes normal collaborative control processes.

[0096] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.

Claims

1. A composite feedforward cooperative control method for ship controllable pitch propeller propulsion, characterized in that, Includes the following steps: S1: Establish a composite propulsion model for controllable pitch propellers, which includes a ship-engine-propeller relationship model, a propulsion main engine characteristics and limitation model, a hydraulic coupler characteristics model, a controllable pitch propeller characteristics model, a controllable pitch propeller collaborative control model, and a ship load inquiry function model. The coordinated control model for controllable pitch propeller propulsion establishes coordinated control between main engine speed and throttle, hydraulic coupler output speed, and controllable pitch propeller speed and pitch. The ship load interrogation function model identifies the ship's resistance characteristics, establishes the characteristic relationships between ship speed and main engine power and between ship speed and controllable pitch propeller speed, predicts the required main engine power and propeller speed at different ship speeds in advance, and calculates the real-time difference between the current main engine power and the maximum continuous main engine power as the current power margin. A power margin limit threshold is set to determine the maximum continuous main engine power margin Δ. P max and host security threshold; S2: Calculate the speed deviation between the set speed and the actual speed, and input the speed deviation into the ship speed closed-loop progressive PID control loop to generate a progressively changing desired speed sequence. S3: For each desired speed value in the desired speed sequence, call the ship load query function model to predict the main engine power and controllable pitch propeller speed required to achieve the desired speed; calculate the power demand increment based on the predicted main engine power and the current main engine power; compare the power demand increment with a predetermined main engine safety threshold; if the power demand increment exceeds the main engine safety threshold, generate a feedforward protection command to reduce the controllable pitch propeller pitch in advance. S4: At the host security threshold δ ME Within the permissible range, using the aforementioned controllable pitch propeller propulsion cooperative control model, one of the following three cooperative control modes is selected and executed according to the navigation conditions: Main engine constant speed mode: The main engine speed is controlled as a constant value, in conjunction with the main engine throttle. L Tracking pitch propeller H p Adjustment, i.e., pitch-throttle linkage control mode; Controlled pitch propeller fixed pitch mode: based on the pitch of the controlled pitch propeller H p The main engine speed is a constant value. n e Closed-loop control, coordinated with main engine throttle L According to the main unit speed n e Follow-up adjustment, i.e., the main engine speed-throttle linkage control mode; Main unit constant power mode: based on the main unit throttle L The output speed of the hydraulic coupling is a constant value. n p - Pitch H p Cooperative control, namely the controllable pitch propeller speed-pitch joint control mode.

2. The composite feedforward cooperative control method for ship controllable pitch propeller propulsion according to claim 1, characterized in that, In step S1, the power margin limit threshold is set to be no less than 5% of the host's rated power; The ship-engine-propeller relationship model includes an engine-propeller characteristic sub-model, a ship resistance characteristic sub-model, and a ship-propeller characteristic sub-model. The formula for the engine-propeller characteristic sub-model is: ； In the formula, J To increase the rotational inertia of the shaft system, n e For the main unit's rotation speed, n p For the controllable pitch propeller speed, M e For the main unit to output torque, M p For the torque of the controllable pitch propeller, M m This refers to the frictional torque of the shaft system. ； In the formula, P p For controllable pitch propeller power, P ME This refers to the output power of the main unit. η c For shaft transmission efficiency; The formula for the ship resistance characteristic sub-model is as follows: ； In the formula, R For ship resistance, α R The drag coefficient, v s For ship speed, m For ship index; The formula for the ship-propeller characteristic sub-model is: ； In the formula, M For ship quality, v s For ship speed, T For the thrust of the controllable pitch propeller, ∑ T This indicates propulsion by two or more controllable pitch propellers. R For the resistance of the ship's motion; ； In the formula, P R To maximize the propulsion power of the controllable pitch propeller, η s For hull efficiency, η p To improve the efficiency of the controllable pitch propeller in flowing water, η x To improve the rotational efficiency of the controllable pitch propeller P p This refers to the power of the controllable pitch propeller.

3. The composite feedforward cooperative control method for ship controllable pitch propeller propulsion according to claim 1, characterized in that, In step S1, the main engine characteristics and limiting models include the controllable pitch propeller fixed pitch FPP propulsion mode, variable pitch CPP propulsion mode, main engine speed characteristics, main engine load characteristics, and limiting characteristics of the main engine's allowable operating range: When the constant pitch FPP propulsion mode is a constant pitch control at a certain pitch, it enters the main engine speed and throttle coordinated control mode. The variable pitch CPP propulsion mode is a composite coordinated control mode of main engine speed-throttle-pitch; The main engine speed characteristics are obtained by constant throttle control at different throttle levels, resulting in full-load speed characteristics, overload speed characteristics, and partial-load speed characteristics. Based on these main engine speed characteristics, the torque curve representing the relationship between the main engine torque and speed is obtained. M e = f ( n e ); The host load characteristic is obtained by constant speed control at different speeds to achieve the host's economic load, power curve. P e = f ( n e Under constant speed, the main engine power changes linearly with increasing load; The operating range of the host is the maximum and minimum power that the host can reach at various speeds, as well as the maximum and minimum speeds that the host can reach under various loads. The main engine limiting characteristic curves include the constant torque limiting curve and the constant exhaust temperature limiting line, which are used to limit the main engine's excessive mechanical load and excessive thermal load, respectively.

4. The composite feedforward cooperative control method for ship controllable pitch propeller propulsion according to claim 1, characterized in that, In step S1, the hydraulic coupler characteristic model converts the main engine's speed and torque into the controllable pitch propeller's speed and torque. The relationship between the input / output speed and torque and the hydraulic coupler's gear ratio is visualized through the hydraulic coupler's operating characteristic curve. When the hydraulic coupler is engaged, the main engine torque, hydraulic coupler torque, and controllable pitch propeller torque are balanced. The main engine's operating conditions and the controllable pitch propeller are optimally matched through the hydraulic coupler's characteristic relationship to prevent the propeller from being too heavy or too light.

5. The composite feedforward cooperative control method for ship controllable pitch propeller propulsion according to claim 1, characterized in that, In step S1, the controllable pitch propeller propulsion characteristic model includes a controllable pitch propeller torque sub-model, a controllable pitch propeller thrust sub-model, a controllable pitch propeller power sub-model, and a controllable pitch propeller flow efficiency sub-model: The formula for the controllable pitch propeller torque sub-model is: ， In the formula, M p For controllable pitch propeller torque, K M This is the torque coefficient of the controllable pitch propeller. ρ The mass density of water, D The diameter of the controllable pitch propeller. n p This refers to the controllable pitch propeller speed; The formula for the controllable pitch propeller thrust sub-model is: ， In the formula, T For controllable pitch propeller thrust, K T This is the thrust coefficient of the controllable pitch propeller. D The diameter of the controllable pitch propeller. n p This refers to the controllable pitch propeller speed; The formula for the controllable pitch propeller power sub-model is: ， In the formula, P p For controllable pitch propeller power, K M This is the torque coefficient of the controllable pitch propeller. ρ The mass density of water, D The diameter of the controllable pitch propeller. n p This refers to the controllable pitch propeller speed; The formula for the flow efficiency sub-model of the controllable pitch propeller is: ， In the formula, η p To improve the efficiency of the controllable pitch propeller in flowing water; T For controllable pitch propeller thrust; v p The advance speed of the controllable pitch propeller is equal to the speed of the ship. v s； n p This refers to the controllable pitch propeller speed; D The diameter of the controllable pitch propeller; M p This refers to the torque of the controllable pitch propeller.

6. The composite feedforward cooperative control method for ship controllable pitch propeller propulsion according to claim 1, characterized in that, In step S3, the host security threshold is set. δ ME Δ is 95% of the host's maximum continuous power margin. P max At the host security threshold δ ME Within permissible limits, the composite feedforward cooperative control pitch control process for pitch-controlled propellers must satisfy the following relationship: ， In the formula, P p For controllable pitch propeller power, P emax This is the maximum continuous power of the host. β 1 represents the transmission efficiency of the hydraulic coupling and shaft system. β 2 represents the influence coefficient after the interaction between the ship and the paddle; Among them, the main unit output power P ME Less than the host's maximum continuous power P emax ,Right now P ME ≤ P emax Main unit output power P ME for: ， In the formula, k 1. k 2 and k 3 represents the external characteristic curve parameters of the host computer. n e This refers to the main unit's rotational speed; The host's maximum continuous power margin Δ P max The calculation formula is: ， The host security threshold δ ME The calculation formula is: ， In the formula, δ ME Δ is the host security threshold. P max This is the maximum continuous power margin of the host. P emax This represents the maximum continuous power of the host unit.

7. The composite feedforward cooperative control method for ship controllable pitch propeller propulsion according to claim 1, characterized in that, In step S4, when controlling the ship's speed in the main engine constant speed mode, the throttle-pitch cooperative control model is as follows: ， ， In the formula, L For the main engine throttle, H p For the pitch of the controllable propeller, v s For the ship's speed, n p This refers to the controllable pitch propeller speed; D λ is the diameter of the controllable propeller; λ is the pitch. H p With speed v s Rotation speed n p The two-variable function between them, through flexible adjustment of pitch H p and rotational speed n p These two parameters determine the optimal propulsion performance, maneuverability, and main engine protection under different operating conditions; Ψ represents the engine throttle. L With pitch H p The function between these parameters was obtained through sea trials of the ship to determine the different pitches of the controllable propeller at constant main engine speed. H p -Main power P ME The numerical curve of throttle L; When controlling the ship's speed in the fixed-pitch controllable propeller mode, the main engine speed closed-loop control, with the controllable propeller pitch as a constant, is achieved using a PID controller combined with dynamic compensation ε; the main engine speed-throttle coordinated control model is as follows: ， In the formula, K p , K I and K d These are the adjustable proportional coefficient, integral coefficient, and differential coefficient, respectively. n e For the main engine speed deviation, ε For dynamic compensation, the data is trained using a deep learning algorithm. The main engine constant power mode is suitable for ship navigation in adverse sea conditions. When the ship speed decreases due to disturbances, the pitch is increased and the hydraulic coupling is adjusted to reduce the speed of the controllable pitch propeller. n p This achieves low-speed, high-thrust control; when the ship speed increases due to disturbances, the control only reduces the pitch to achieve high-speed, light-load control, all to maintain ship speed and main engine power. P ME The goal is to maintain a constant speed; the controllable propeller speed-pitch linkage under constant main engine power is as follows: ， ， ， In the formula, P ME This refers to the output power of the main unit. K o For the controllable pitch propeller propulsion coefficient, Γ(H p / D) For controllable pitch propeller thrust, v s For ship speed, L This refers to the engine throttle (fuel injection quantity). n p For the controllable pitch propeller speed, H p For the pitch of the controllable propeller, η o To improve efficiency, S For slippage rate, K G γ is the adjustable gear ratio of the variable speed hydraulic coupling; γ is a function of the main engine power and throttle, calibrating the relationship between the main engine power and the fuel injection quantity; Γ is the thrust related to the pitch of the controllable propeller, meaning the adjustment of the pitch. H p The thrust magnitude and direction can be set quickly and directly, improving the high maneuverability, high controllability and wide operating condition adaptability of the controllable propeller; The hydraulic coupling is used to replace the reduction gearbox to buffer the impact of the propeller on the main engine and is suitable for ship navigation in ice-covered areas.

8. A composite feedforward cooperative control system for ship controllable pitch propeller propulsion, characterized in that, The system for implementing the method according to any one of claims 1-7 comprises: Data processing and modeling unit: used to store and run the controllable pitch propeller propulsion composite model, specifically performing the ship load query function, the ship speed closed-loop progressive control calculation, and the main engine safety threshold calculation; Data acquisition unit: used to acquire ship speed, main engine speed, main engine power, controllable pitch propeller pitch, throttle position and hydraulic coupler output speed signals in real time; Cooperative control decision unit: used to calculate power margin, determine host safety threshold and select cooperative control mode; The execution unit includes a main engine speed regulation and throttle actuator, a hydraulic coupler gear ratio control mechanism, and a pitch control propeller pitch hydraulic adjustment mechanism, which are communicatively connected to the collaborative control decision unit, and is used to execute the collaborative control commands.

9. A ship, characterized in that, It is equipped with a composite feedforward cooperative control system for ship controllable pitch propeller propulsion as described in claim 8.

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