Speed control method of ship main engine speed control system based on incremental PID algorithm

Abstract

The application discloses a kind of based on the speed regulating method of ship main engine speed control system of incremental PID algorithm, first preset ship main engine speed: preset the corresponding value of each gear injection quantity and speed;Then determine the relationship between injection quantity and speed;Finally, the ship main engine speed is adjusted.The speed regulating method of ship main engine speed of the application adopts PID control algorithm, the differential element in PID control algorithm can judge the change trend of ship main engine speed according to the change speed of deviation, realize the role of advance adjustment to main engine speed;PID parameter self-setting mode is used to avoid the influence brought by different ship types and different loads, increase the applicability of the method;Meanwhile, the application sets the trigger condition of main engine speed adjustment, avoids that main engine speed adjustment is too frequent, eliminates the shock caused by frequent action;And according to the change relationship between speed and injection quantity, the state of propeller in seawater is judged.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ship main engine speed control, and particularly relates to a speed regulation method of a ship main engine speed control system based on an incremental PID algorithm. BACKGROUND

[0002] When the ship is sailing on the sea, the speed of the main engine is controlled by changing the fuel injection amount. When the fuel injection amount of the main engine increases and the speed does not increase, the mechanical load will be too large.

[0003] During the sailing process of the ship, the ship often encounters adverse sea conditions such as strong wind and waves. When the ship encounters adverse sea conditions, the movement amplitude of the ship in the vertical direction will increase, thereby causing the propeller to frequently enter and exit the water surface. When the propeller changes from underwater to above water, and the fuel injection amount of the ship main engine does not change or changes little, accompanied by a decrease in load, the propeller speed will soar. When the propeller changes from above water to underwater, and the fuel injection amount of the ship main engine does not change or changes little, accompanied by an increase in load, the propeller speed will decrease. Therefore, when the ship encounters adverse sea conditions, if the control is not proper, the mechanical load and thermal load will exceed the bearing range of the engine, causing mechanical damage and thermal damage to the engine, which may cause fuel waste, increase of pollutant emission, and shorten the service life of the engine, or even cause the engine to be damaged and people to be killed.

[0004] At present, the existing main engine speed control method cannot well solve the above problems. For example, the "control method and device for fuel injection amount when engine torque suddenly increases" described in CN103032188B gives a control method for fuel injection amount when the torque of a vehicle changes, but since the working conditions of a ship in the sea are more complex and changeable than those of a vehicle on land, the control method is not suitable for the control of the fuel injection amount of the ship main engine. For another example, the paper "Simulation of Ship Electric Propulsion System Control Strategy in Adverse Sea Conditions" published by Liao Linhao, Gao Haibo, et al. in the Journal of Dalian Maritime University (No. 1, 2020) obtains a relatively optimal strategy for solving the sudden change of propeller speed caused by the frequent entry and exit of the propeller into the water surface by comparing a plurality of propeller speed control strategies in adverse sea conditions, but the strategy cannot make an advance adjustment to the propeller speed according to the change of the sea conditions. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a speed regulation method of a ship main engine speed control system based on an incremental PID algorithm, which improves the safety of ship operation.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is: a speed regulation method of a ship main engine speed control system based on an incremental PID algorithm, wherein the ship main engine speed control system comprises a general control system, a PID controller, a collector, an operator and a ship main engine assembly; the collector collects data of the ship main engine assembly and sends the data to the operator for processing, the PID controller adjusts the control strategy according to the processing result of the operator, and the general control system controls the ship main engine assembly; the collector comprises a speed sensor, a fuel pressure sensor and a diesel cylinder table, the speed sensor is used to measure the real-time speed of the ship main engine, the fuel pressure sensor is used to measure the fuel pressure of the fuel injector nozzle, and the diesel cylinder table is used to measure the diesel cylinder pressure;

[0007] The specific steps of the control method are as follows:

[0008] Step 1: presetting the corresponding values of the fuel injection amount and the speed of each gear of the ship main engine;

[0009] Step 2: determining the relationship between the fuel injection amount and the speed

[0010] 2.1: the general control system obtains the data cluster G1 collected in the previous period by accessing the database j (P xj前 , P zj前 , Nr j前 ), j is a positive integer, wherein P xj前 is the fuel pressure of the fuel injector nozzle, which is measured by the fuel pressure sensor, P xj前 is the diesel cylinder pressure, which is measured by the diesel cylinder table, and Nr j前 is the main engine speed, which is measured by the speed sensor;

[0011] 2.2: the general control system calculates the fuel injection amount Q j前 of the main engine according to the following formula (1): Then, the data cluster G1 j is simplified to the data cluster G2 j (Q j前 , Nr j前 );

[0012] In formula (1), ρ x is the density of the fuel injector nozzle, which is a known quantity; P x is the fuel pressure of the fuel injector nozzle; P Z is the diesel cylinder pressure; u x is the flow coefficient of the nozzle, which is determined when the nozzle type is determined; and A x is the cross-sectional area of the nozzle, which is determined when the nozzle type is determined;

[0013] 2.3: The total control system traverses the data cluster G2 j and compared with formula (2):

[0014]

[0015] When G2 j satisfies any condition in formula (2), the data set is discarded; when G2 j does not satisfy any condition in formula (2), the data set is saved to form a data cluster G3 n (0≤n≤j), wherein the data cluster G3 n is the corresponding relationship between the fuel injection quantity and the rotation speed when the propeller is in the half-submerged state;

[0016] Q1-Q10 are the fuel injection quantities of the "first gear", "second gear", "third gear", "fourth gear", "fifth gear", "first reverse gear", "second reverse gear", "third reverse gear", "fourth reverse gear", and "fifth reverse gear" of the ship type; Nr1-Nr10 are the rotation speeds of the "first gear", "second gear", "third gear", "fourth gear", "fifth gear", "first reverse gear", "second reverse gear", "third reverse gear", "fourth reverse gear", and "fifth reverse gear" of the ship type;

[0017] 2.4: The total control system calls MATLAB software to analyze and calculate the data cluster G3 n , and obtains the relationship formula (3) between the fuel injection quantity Q and the rotation speed n when the propeller is in the half-submerged state:

[0018] Q=f1(n) (3)

[0019] Step 3: Adjust the rotation speed of the ship main engine

[0020] 3.1: The total control system obtains the current gear of the ship main engine, determines the rotation speed Nr g and the fuel injection quantity Q g specified by the gear;

[0021] 3.2: The rotation speed sensor collects the real-time rotation speed Nr11 k of the main engine every t1, and calculates the difference ΔNr" between the real-time rotation speed Nr11 k and the target rotation speed: ΔNr"=Nr11 k -Nr g

[0022] 3.3: The fuel pressure sensor and the diesel cylinder table measure the fuel pressure P x of the fuel injector nozzle and the cylinder pressure P Z of the diesel engine, and the total control system calculates the fuel injection quantity Q11 k ​; and calculates the difference ΔQ" between the value of the real-time fuel injection quantity and the fuel injection quantity corresponding to the target rotational speed: ΔQ" = Q11 k - Q g ;

[0023] 3.4: According to the values of ΔNr" and ΔQ", the total control system obtains the current working condition of the marine engine and the state of the propeller by inquiring the following marine engine working condition table: if the marine engine is in working condition one, it indicates that the propeller rotational speed is normally fluctuating and no adjustment is needed, and the process goes to step 3.2; if the marine engine is in working condition five or working condition nine, it indicates that the propeller is in the process of gear switching, and the process goes to step 3.5; if the marine engine is in working condition two or working condition three or working condition four or working condition seven, it indicates that the propeller is switching between the fully submerged state and the fully submerged state, and adjustment is needed, and the process goes to step 3.8; if the marine engine is in working condition six or working condition eight, it indicates that the propeller rotational speed is in the process of early adjustment, and adjustment is needed, and the process goes to step 3.2;

[0024]

[0025]

[0026] In the table, e represents the preset maximum value of the rotational speed fluctuation; f represents the preset maximum value of the fuel injection quantity fluctuation;

[0027] 3.5: The rotational speed sensor collects the real-time rotational speed Nr11' of the engine every t1 k , and sends it to the operation unit, which calculates the difference ΔNr' between the real-time rotational speed and the target rotational speed: ΔNr' = Nr11' k - Nr g ;

[0028] 3.6: The fuel pressure of the fuel injector nozzle P' is measured by the fuel pressure sensor and the diesel cylinder table x , and the diesel cylinder pressure P' is measured by the diesel cylinder table z , and sent to the operation unit, which calculates the fuel injection quantity Q11' of the engine according to formula (3) k ; and calculates the difference ΔQ' between the value of the real-time fuel injection quantity and the fuel injection quantity corresponding to the target rotational speed: ΔQ' = Q11' k - Q g ;

[0029] 3.7: The operation unit determines whether ΔNr' ≥ e and ΔQ' ≥ f (or -e ≥ ΔNr' and -f ≥ ΔQ') are true; if true, it indicates that the gear switching has not been completed, and the process goes to step 3.5; if not true, it indicates that the gear switching has been completed, and the process goes to step 3.1;

[0030] 3.8: The total control system obtains the engine rotational speeds Nr11k-2 , Nr11 k-1 , Nr11 k ; and the deviation signals e(k-2), e(k-1), e(k) of the k-2, k-1, k sampling instants are calculated:

[0031] e(k-2) = Nr11 k-2 -Nr g

[0032] e(k-1) = Nr11 k-1 -Nr g

[0033] e(k) = Nr11 k -Nr g ;

[0034] 3.9: The total control system calculates the output of the PID controller at the k (k≥4) sampling instant, i.e. the ship main engine speed u(k);

[0035] u(k) = u(k-1) + K p (e(k) - e(k-1)] + K i e(k) + K d [e(k) - 2e(k-1) + e(k-2)]

[0036] wherein e(k) is the deviation signal at the k instant, i.e. the difference between the measured value of the ship main engine speed and the target speed of the ship main engine;

[0037] K p is the proportional coefficient; K i is the integral coefficient; K d is the differential coefficient; T i is the integral time constant; T d is the differential time constant;

[0038] 3.10: The total control system calculates the fuel injection amount Q(k) required for the speed u(k) according to formula (3);

[0039] 3.11: The total control system changes the fuel injection amount of the ship main engine to Q(k), and goes to step 3.2.

[0040] As a preferred solution, in the step 3.9, the proportional coefficient K p , the integral coefficient K i , the differential coefficient K d , the integral time constant T i , and the differential time constant T d are calculated by the following process:

[0041] S1: Before the ship officially starts sailing, the total control system controls the main engine of the ship to set the idle speed Nr to run;

[0042] S2: Set the integral time constant T i = ∞, the differential time constant T i = 0, and the proportional degree δ to the specified value a; d d

[0043] S3: The speed sensor collects the idle speed Nr' of the main engine of the ship every t1 m (m = 1, 2, 3, 4...) and transmits it to the total control system;

[0044] S4: The total control system fits the speed Nr' into a curve by calling MATLAB software, and finds the maximum value bn m (1 ≤ n ≤ m) and the time tn max corresponding to the maximum value, as well as the minimum value bs max (1 ≤ s ≤ m) and the time ts min corresponding to the minimum value; min

[0045] S5: The total control system makes a judgment

[0046] |b1 max -Nr| = |b2 max -Nr| = … = |bn max -Nr| = |b1 min -Nr| = |b2 min -

[0047] Nr| = … = |bs min -Nr|

[0048] |t2 max -t1 max | = |t3 max -t2 max | = … = |tn max -t(n-1) max | = |t2 min -

[0049] and t1 min | = |t3 min -t2 min | = … = |ts min -t(s-1) min |

[0050] is true, if not, the proportional degree δ is decreased by the selected value Δδ, and bn max , bs min ​​​, tn max and ts min , the values of the critical proportionality δ and the critical oscillation period T are determined, and the process goes to step S3, if true, step S6 is executed;

[0051] S6: determining the value δ of the critical proportionality k and the value T of the critical oscillation period k :

[0052] |b1 max -Nr|=|b2 max -Nr|=…=|bn max -Nr|=|b1 min -Nr|=|b2 min -

[0053] When Nr|=…=|bs min -Nr|

[0054] |t2 max -t1 max |=|t3 max -t2 max |=…=|tr max -t(n-1) max |=|t2 min -

[0055] and t1 min |=|t3 min -t2 min |=…=|ts min -t(s-1) min |, the value of the proportionality δ is the critical proportionality δ k ; at this time, the value of the critical oscillation period T k is T k =t2 max -t1 max ;

[0056] S7: calculating the values of the proportionality coefficient, the integral time constant and the differential time constant:

[0057] the proportionality coefficient K p : the integral time constant T i : T i =d*T k ; the differential time constant T d : T d =h*T k ;

[0058] wherein c, d, h are empirical coefficients;

[0059] S8: calculating the integral coefficient and the differential coefficient:

[0060] Integral coefficient K i : Derivative coefficient K d :

[0061] The beneficial effects of the present application are:

[0062] The ship main engine speed regulating method of the present application adopts a PID control algorithm, the derivative element in the PID control algorithm can judge the change trend of the ship main engine speed according to the deviation change speed, and realize the leading regulation of the main engine speed; the PID parameter self-tuning method is adopted to avoid the influence of different ship types and different loads, and increase the applicability of the method.

[0063] Meanwhile, the present application sets the main engine speed regulation trigger condition to avoid the main engine speed regulation too frequent, and eliminate the shock caused by frequent action;

[0064] And according to the change relationship between the speed and the fuel injection amount, the state of the propeller in the seawater is judged, the fuel injection amount of the main engine is accurately controlled according to the position of the propeller, the waste of fuel and the increase of emission caused by the excessive heat load of the engine are avoided, and the problem of the change of the speed and the increase of the emission caused by the propeller frequently entering and leaving the water surface in the wind and wave is solved. BRIEF DESCRIPTION OF DRAWINGS

[0065] Fig. 1 The constituent diagram of the ship main engine speed control system based on the incremental PID algorithm of the present application

[0066] Fig. 2 The speed regulating method of the ship main engine speed control system of the present application

[0067] In the figure: 1 - total control system, 2 - ship main engine assembly, 3 - collector, 31 - diesel engine cylinder table, 32 - fuel pressure sensor, 33 - speed sensor, 4 - operator, 5 - PID controller. DETAILED DESCRIPTION

[0068] The specific implementation scheme of the present application will be described in detail below in combination with the drawings.

[0069] As Figs. 1-2As shown, a speed regulation method for a ship main engine speed control system based on incremental PID algorithm is disclosed. The ship main engine speed control system includes a central control system 1, a PID controller 5, a data acquisition unit 3, an arithmetic unit 4, and a ship main engine component 2. The data acquisition unit 3 collects data from the ship main engine component and sends it to the arithmetic unit 4 for processing. The PID controller 5 adjusts the control strategy accordingly based on the processing result of the arithmetic unit 4 and controls the ship main engine component 2 through the central control system 1. The data acquisition unit 3 includes a speed sensor 33, a fuel pressure sensor 32, and a diesel engine cylinder gauge 31. The speed sensor 33 is used to measure the real-time speed of the ship main engine, the fuel pressure sensor 32 is used to measure the fuel pressure of the fuel injector nozzle, and the diesel engine cylinder gauge 31 is used to measure the diesel engine cylinder pressure.

[0070] The specific steps of the control method are as follows:

[0071] Step 1: Preset the ship's main engine speed: Preset the corresponding value of the fuel injection quantity and speed for each gear;

[0072] The engine telegraph settings in a ship's main engine remote control system include "forward" (gear 1), "forward" (gear 2), "forward" (gear 3), "forward" (gear 4), "forward" (gear 5), "reverse" (gear 1), "reverse" (gear 2), "reverse" (gear 3), "reverse" (gear 4), and "reverse" (gear 5). The relationship between fuel injection quantity and engine speed for each setting varies depending on the ship type. Table 1 shows the relationship between fuel injection quantity and engine speed for different settings of a certain ship type.

[0073] Table 1. Relationship between fuel injection quantity and engine speed at different gears for a certain ship type.

[0074]

[0075] Step 2: Determine the relationship between fuel injection quantity and engine speed

[0076] 2.1: The central control system obtains the previously collected data cluster G1 by accessing the database. j (P xj前 P zj前 Nr j前 ), where j is a positive integer, and P xj前 The fuel pressure at the injector nozzle is obtained by measuring the fuel pressure sensor, P. zj前 The cylinder pressure of the diesel engine is obtained by measuring the cylinder pressure using a diesel engine cylinder gauge. (Nr) j前 The main unit's rotational speed is obtained through measurement using a speed sensor.

[0077] 2.2: The central control system is based on the following formula (1): Calculate the fuel injection quantity Q of the main unit j前 Then put data cluster G1 j Simplified to data cluster G2 j (Q j前, Nr j前 );

[0078] In formula (1), p x is the density of the fuel injector nozzle, which is a known quantity; P x is the fuel pressure of the fuel injector nozzle; P Z is the cylinder pressure of the diesel engine; u x is the flow coefficient of the nozzle, which is determined when the nozzle type is determined; A x is the cross-sectional area of the nozzle, which is determined when the nozzle type is determined;

[0079] 2.3: The total control system traverses the data cluster G2 j and compares it with formula (2):

[0080]

[0081] When G2 j satisfies any condition in formula (2), the data set is discarded; when G2 j does not satisfy all conditions in formula (2), the data set is saved to form a data cluster G3 n (0≤n≤j), wherein the data cluster G3 n is the corresponding relationship between the fuel injection quantity and the rotational speed when the propeller is in the half-submerged state;

[0082] ΔQ is the allowable error value between the preset gear fuel injection quantity in the main engine fuel injection quantity in the data cluster G2 j (Q j前 , Nr j前 ), and ΔNr is the allowable error value of the main engine rotational speed and the main engine rotational speed of the preset gear collected in the early stage;

[0083] 2.4: The total control system analyzes and calculates the data cluster G3 n by calling MATLAB software to obtain the change relationship formula (3) of the fuel injection quantity Q with the rotational speed n when the propeller is in the half-submerged state:

[0084] Q=f1(n) (3)

[0085] Step 3: Adjust the rotational speed of the ship main engine

[0086] 3.1: The total control system obtains the current gear of the ship main engine to determine the rotational speed Nr g and the fuel injection quantity Q g of the gear (wherein g=1~10 and is an integer);

[0087] 3.2: The rotational speed sensor collects the real-time rotational speed Nr11 k of the main engine every t1, and calculates the real-time rotational speed Nr11 kThe difference between the target speed and the actual speed ΔNr": ΔNr" = Nr11 k -Nr g ;

[0088] 3.3: Measure the fuel pressure P of the injector nozzle by the fuel pressure sensor and the diesel cylinder table x The difference between the target speed and the actual speed ΔNr": ΔNr" = Nr11 Z , the total control system calculates the fuel injection quantity Q11 of the main engine according to formula (1) k ; and calculates the difference ΔQ" between the value of the real-time fuel injection quantity and the fuel injection quantity corresponding to the target speed: ΔQ" = Q11 k -Q g ;

[0089] 3.4: According to the values of ΔNr" and ΔQ", the total control system obtains the current working condition of the main engine and the state of the propeller by inquiring the following table of working conditions of the main engine of the ship; if the main engine is in working condition one, it indicates that the propeller speed normally fluctuates and no adjustment is needed, and the process goes to step 3.2; if the main engine is in working condition five or working condition nine, it indicates that the propeller is in the process of gear switching, and the process goes to step 3.5; if the main engine is in working condition two or working condition three or working condition four or working condition seven, it indicates that the propeller is switching between the fully submerged state and the fully submerged state, and adjustment is needed, and the process goes to step 3.8; if the main engine is in working condition six or working condition eight, it indicates that the propeller speed is in the process of early adjustment, and adjustment is needed, and the process goes to step 3.2;

[0090]

[0091] In the table, e represents the maximum value of the preset speed fluctuation; f represents the maximum value of the preset fuel injection quantity fluctuation;

[0092] 3.5: The speed sensor 33 collects the real-time speed Nr11' of the main engine every t1 k , and sends it to the operator 4, which calculates the difference ΔNr' between the real-time speed and the target speed: ΔNr' = Nr11' k -Nr g ;

[0093] 3.6: Measure the fuel pressure P' of the injector nozzle by the fuel pressure sensor 32 and the diesel cylinder table 31 x The difference between the target speed and the actual speed ΔNr": ΔNr" = Nr11 z , and sends it to the operator 4, which calculates the fuel injection quantity Q11' of the main engine according to formula (3) k ; and calculates the difference ΔQ' between the value of the real-time fuel injection quantity and the fuel injection quantity corresponding to the target speed: ΔQ' = Q11' k -Q g ;

[0094] 3.7: The operator 4 judges whether ΔNr' ≥ e and ΔQ' ≥ F (or -e ≥ ΔNr' and -f ≥ ΔQ') are true; if true, it indicates that the gear shifting is not completed, and goes to step 3.5; if not true, it indicates that the gear shifting is completed, and goes to step 3.1;

[0095] 3.8: The total control system obtains the main engine rotating speed Nr11 k-2 , Nr11 k-1 , Nr11 k of the k-2, k-1, k sampling time through the speed sensor, and calculates the deviation signal e(k-2), e(k-1), e(k) of the k-2, k-1, k sampling time:

[0096] e(k-2) = Nr11 k-2 - Nr g

[0097] e(k-1) = Nr11 k-1 - Nr g

[0098] e(k) = Nr11 k - Nr g ;

[0099] 3.9: The total control system calculates the output of the PID controller of the k (k ≥ 4) sampling time, i.e. the ship main engine rotating speed u(k);

[0100] Wherein, e(k) is the deviation signal at k time, i.e. the difference between the measured value of the ship main engine rotating speed and the target rotating speed of the ship main engine; K p is the proportional coefficient; K i is the integral coefficient; K d is the differential coefficient; T i is the integral time constant; T d is the differential time constant;

[0101] The proportional coefficient K p , the integral coefficient K i , the differential coefficient K d , the integral time constant T i , and the differential time constant T d are calculated by the following process:

[0102] S1: Before the ship officially starts sailing, the total control system controls the ship main engine to run at the set idling speed Nr;

[0103] S2: The integral time constant T i is set as T i = ∞, and the differential time constant T d is set as Td = 0, and the proportional degree δ is set to a specified value a;

[0104] S3: The rotation speed sensor collects the rotation speed Nr' of the main engine of the ship running at idle speed every t1 m (m = 1, 2, 3, 4,...), and transmits it to the general control system;

[0105] S4: The general control system calls MATLAB software to fit the rotation speed Nr' m into a curve, and finds the maximum value bn max (1≤n≤m) and the time tn max corresponding to the maximum value, and the minimum value bs min (1≤s≤m) and the time ts min corresponding to the minimum value;

[0106] S5: The general control system makes a judgment

[0107] |b1 max -Nr| = |b2 max -Nr| =... = |bn max -Nr| = |b1 min -Nr| = |b2 min -

[0108] Nr| =... = |bs min -Nr|

[0109] |t2 max -t1 max | = |t3 max -t2 max | =... = |tn max -t(n-1) max | = |t2 min -

[0110] and t1 min | = |t3 min -t2 min | =... = |ts min -t(s-1) min |

[0111] , if not, the proportional degree δ is decreased by a selected value Δδ, and the values of bn max , bs min , tn max and ts min are cleared, and the process goes back to step S3, if yes, step S6 is executed;

[0112] S6: The value δ of the critical proportional degree and the value T of the critical oscillation period are determined k .k :

[0113] |b1 max -Nr|=|b2 max -Nr|=…=|bn max -Nr|=|b1 min -Nr|=|b2 min -

[0114] When Nr|=…=|bs min -Nr|

[0115] |t2 max -t1 max |=|t3 max -t2 max |=…=|tn max -t(n-1) max |=|t2 min -

[0116] and t1 min |=|t3 min -t2 min |=…=Its min -t(s-1) min |

[0117] the value of the proportional degree δ is the critical proportional degree δ k ; at this time, the value of the critical oscillation period T k is T k =t2 max -t1 max ;

[0118] S7: Calculate the values of the proportional coefficient, the integral time constant and the differential time constant:

[0119] the proportional coefficient K p : the integral time constant T i : T i =d*T k ; the differential time constant T d : T d =h*T k ;

[0120] where c, d, h are empirical coefficients;

[0121] S8: Calculate the integral coefficient and the differential coefficient:

[0122] the integral coefficient K i : the differential coefficient K d : where T is the adjustment period;

[0123] 3.10: The total control system calculates the required fuel injection amount Q(k) for the rotation speed u(k) according to formula (3);

[0124] 3.11: The total control system changes the fuel injection amount of the ship main engine to Q(k), and goes to step 3.2.

[0125] The above embodiments only illustrate the principles and effects of the present application, and part of the embodiments used, but are not used to limit the present application; it should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application.

Claims

1. A speed regulating method of a marine engine speed control system based on an incremental PID algorithm, wherein the marine engine speed control system comprises a master control system, a PID controller, a collector, an operator and a marine engine assembly; the collector collects data of the marine engine assembly and sends the data to the operator for processing, the PID controller adjusts a control strategy according to the processing result of the operator, and the master control system controls the marine engine assembly; the collector comprises a speed sensor, a fuel pressure sensor and a diesel cylinder gauge, the speed sensor is used to measure a real-time speed of the marine engine, the fuel pressure sensor is used to measure a fuel pressure of an injector nozzle, and the diesel cylinder gauge is used to measure a diesel cylinder pressure; The specific steps of the control method are as follows: Step 1: presetting a marine engine speed: presetting corresponding values of an injection amount and a speed of each gear; Step 2: determining a relationship between the injection amount and the speed 2.1: The total control system obtains the data cluster G1 collected in the previous stage by accessing the database j (P xj前 , P zj前 , Nr j前 ), j is a positive integer, wherein, P xj前 P is the fuel pressure of the fuel injector, measured by a fuel pressure sensor zj前 Nr is the cylinder pressure of the diesel engine, measured by a cylinder pressure sensor j前 N is the engine speed, measured by a speed sensor 2.2: The total control system calculates the injection quantity Q of the engine according to the following equation (1): Q = (P j前 , Nr j ) - (P xi前 , Nr zi前 ) i前 ) = (Q j , Nr i前 ) (1) i前 ; In formula (1), p x is the density of the fuel in the injector nozzle, which is a known quantity; P x is the fuel pressure in the injector nozzle; P Z is the cylinder pressure of the diesel engine; u x is the flow coefficient of the nozzle, which is determined when the nozzle type is determined; A x is the cross-sectional area of the nozzle, which is determined when the nozzle type is determined; 2.3: The total control system traverses the data cluster G2 j (Q j前 , Nr j前 ) and compares it to equation (2): When G2 j (Q j前 , Nr j前 ) meets any condition in formula (2), the group of data is discarded; when G2 j (Q j前 , Nr j前 ) does not meet all conditions in formula (2), the group of data is saved to form a data cluster G3 n (0≤n≤j), wherein the data cluster G3 n is a corresponding relationship between the fuel injection quantity and the rotation speed when the propeller is in a half-submerged state. Q1-Q10 are injection amounts of "advance one", "advance two", "advance three", "advance four", "advance five", "retreat one", "retreat two", "retreat three", "retreat four" and "retreat five" gears of the ship type; Nr1-Nr10 are speeds of the "advance one", "advance two", "advance three", "advance four", "advance five", "retreat one", "retreat two", "retreat three", "retreat four" and "retreat five" gears of the ship type; 2.4: The total control system analyzes and calculates the data cluster G3 by calling MATLAB software to obtain the relationship between the fuel injection quantity Q and the rotational speed n when the propeller is in the half-submerged state (3): n The relationship between the fuel injection quantity Q and the rotational speed n when the propeller is in the half-submerged state (3): Q=f1(n) (3) Step 3: regulating the marine engine speed 3.1: Obtain the current gear of the main engine of the ship through the total control system, and determine the speed Nr specified by the gear a and the fuel injection quantity Q g ; 3.2: The speed sensor collects the real-time speed Nr11 of the host every t1 k and calculates the real-time speed Nr11 k The difference ΔNr" between the target speed and the real-time speed: ΔNr" = Nr11 k -Nr g ; 3.3: Fuel pressure P of the injector nozzle is measured by a fuel pressure sensor and a diesel cylinder pressure gauge x With diesel cylinder pressure P Z , the total control system calculates the fuel injection amount Q11 of the main engine according to formula (1) k ; and calculates the difference AQ" between the value of the real-time fuel injection amount and the fuel injection amount corresponding to the target rotation speed: AQ" = Q11 k - Q g ; 3.4: the master control system acquires a current working condition of the marine engine and a propeller state by querying the following marine engine working condition table according to values of ΔNr" and ΔQ"; if the marine engine is in working condition one, it indicates that the propeller speed normally fluctuates and does not need to be adjusted, and the process returns to step 3.2; if the marine engine is in working condition five or working condition nine, it indicates that the propeller is in a gear switching process, and the process returns to step 3.5; if the marine engine is in working condition two or working condition three or working condition four or working condition seven, it indicates that the propeller is switching between a full-water state and a full-submerged state, and needs to be adjusted, and the process returns to step 3.8; if the marine engine is in working condition six or working condition eight, it indicates that the propeller speed is in a preliminary adjustment process, and needs to be adjusted, and the process returns to step 3.2; In the table, e represents a preset maximum value of speed fluctuation; f represents a preset maximum value of injection amount fluctuation; 3.5: the speed sensor collects the real-time speed Nr11' of the host every t1 k and sends it to the operator, which calculates the difference ΔNr' between the real-time speed and the target speed: ΔNr' = Nr11' k -Nr g ; 3.6: Measure the fuel pressure P′ at the injector nozzle using a fuel pressure sensor and a diesel engine cylinder gauge. x With diesel engine cylinder pressure P′ z The data is then sent to the arithmetic unit, which calculates the fuel injection quantity Q11′ of the main unit according to formula (3). k And calculate the difference ΔQ′ between the real-time injection quantity and the injection quantity corresponding to the target speed: ΔQ′=Q11′ k -Q g ; 3.7: the operator determines whether ΔNr'≥e and ΔQ'≥f (or -e≥ΔNr' and -f≥ΔQ') are true; if true, it indicates that the gear switching has not been completed, and the process returns to step 3.5; if not true, it indicates that the gear switching has been completed, and the process returns to step 3.1; 3.8: The total control system obtains the host speed Nr11 at the k-2, k-1, and k acquisition instants through the speed sensor k-2 , Nr11 k-1 , Nr11 k ; and calculates the deviation signals e(k-2), e(k-1), and e(k) at the k-2, k-1, and k acquisition instants e(k-2) = Nrll k-2 -Nr g e(k-1) = Nr11 k-1 -Nr g e(k) = Nr 11 k -Nr g ; 3.9: the master control system calculates an output of the PID controller at a k(th) (k≥4) collection time, i.e. a marine engine speed u(k); u(k) = u(k - 1) + K p [e(k) - e(k - 1)] + K c e(k) + K d [e(k) - 2e(k - 1) + e(k - 2)] wherein e(k) is a deviation signal at the k(th) time, i.e. a difference between a measured value of the marine engine speed and a target speed of the marine engine; K p is a proportional coefficient; K i is an integral coefficient; K d is a differential coefficient; T i is an integral time constant; Tdis a differential time constant; 3.10: the master control system calculates an injection amount Q(k) required by the speed u(k) according to formula (3); 3.11: the master control system changes the injection amount of the marine engine to Q(k), and the process returns to step 3.

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2. The speed regulation method for a ship main engine speed control system based on incremental PID algorithm as described in claim 1, characterized in that: The proportional coefficient K p , the integral coefficient K i , the derivative coefficient K d , the integral time constant T i , and the derivative time constant Td are calculated by the following processes: S1: Before the ship formally starts sailing, the total control system controls the main engine of the ship to set the idling speed Nr to run; S2: Set the integration time constant T i to T i = ∞, the differentiation time constant T d to T d = 0, and the proportional degree δ to a specified value a; S3: the rotation speed sensor collects the rotation speed Nr' of the main engine of the ship running at idle speed every t1 m (m = 1, 2, 3, 4,...), and transmits to the general control system; S4: The central control system uses MATLAB software to control the rotational speed Nr′ m Fit the curve to a graph and find the maximum value bn of the curve. max (1≤n≤m) and the time tn corresponding to the maximum value max and the minimum value bs min (1≤s≤m) and the time ts corresponding to the minimum value min ; S5: The total control system judges |bl max -Nr| = |b2 max -Nr| =... = |bn max -Nr| = |b1 min -Nr| = |b2 min -Nr| =... = |bs min -Nr| |t2 max -t1 max |t3 max -t2 max tn max -t(n-1) max |t2 min - and t1 min | = | t3 min - t2 min | =... = | ts min - t(s-1) min | whether or not, if not, the proportion δ is decreased by a selected value Δδ and the values of bn max , bs min , tn max and ts min are emptied, while passing to step S3, if yes, step S6 is executed; S 6: determining the value δ of the critical proportionality k and the value T of the critical oscillation period k : |b1 max -Nr| = |b2 max -Nr| =... = |bn max -Nr| = |b1 min -Nr| = |b2 min - when |Nri =... = |bs min -Nr| |t2 max -t1 max |t3 max -t2 max tn max -t(n-1) max |t2 min - and t1 min | = | t3 min - t2 min | =... = | ts min - t(s-1) min | At this time, the value of the critical proportional degree δ is the value of the proportional degree δ k ; at this time, the value of the critical oscillation period T k is T k = t2 max - t1 max ; S7: The values of the proportional coefficient, the integral time constant and the differential time constant are calculated: proportionality factor K p : integration time constant T i : T i = d * T k ; differentiation time constant T d : T d = h * T k ; Wherein, c, d, h are empirical coefficients; S8: The integral coefficient and the differential coefficient are calculated: Integral coefficient K t : Derivative coefficient K d :

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