A lifting compensation control method and lifting system for offshore operating vessels

Abstract

The present invention discloses a lifting compensation control method and lifting system for a marine operating ship, which belongs to the technical field of marine ship equipment. The method includes: constructing a model of a barge-marine engineering structure-hydraulic servo system, and obtaining a state equation of the model; obtaining the actual displacement of the barge and the marine engineering structure and the actual pressure of the rod chamber and the rodless chamber of the hydraulic cylinder; calculating the estimated displacement and the estimated pressure; performing an expansion state estimation on the unknown variables of the state equation according to the error between the actual displacement and the estimated displacement, the actual pressure and the estimated pressure, and calculating the internal disturbance of the hydraulic cylinder during use; performing feedforward compensation on the internal disturbance and the external disturbance generated by the barge to obtain the actual control amount of the hydraulic servo system; inputting the actual control amount into the model to change the force of the hydraulic cylinder on the marine engineering structure. The present invention can realize the precise control of the displacement of the marine engineering structure, and has the advantages of low complexity and good resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of marine ship equipment, and in particular relates to a lifting compensation control method and a lifting system for a marine operating ship. Background Art

[0002] The installation of marine engineering structures is an important part of the development of marine resources. Its development is becoming more and more modular, and most of them adopt the method of building first and then installing. Among the many installation methods, floating technology has the advantages of low cost and large load weight. In the load transfer stage of the floating operation, in order to ensure the smooth docking between the marine engineering structure and the pile legs of the offshore platform, to achieve the smooth descent of the marine engineering structure and not to collide violently with the pile legs, a heave compensation device will be installed between the floating vessel and the marine engineering structure to compensate for the disturbance of the waves. Due to the complex dynamic coupling between the floating vessel and the environmental field, the floating barge, the upper marine engineering structure and the compensation device, the displacement stability control of the upper marine engineering structure is challenged. At present, the hydraulic heave compensation system is mainly analyzed and studied for the accuracy of its model, and the control is also carried out based on traditional methods. It is difficult to solve the parameter uncertainty and strong coupling problems of complex systems, resulting in poor anti-disturbance and poor compensation quality of the heave compensation system.

[0003] In view of this, how to design a compensation control method with good anti-disturbance and good compensation quality is the technical problem to be solved by the present invention. Summary of the invention

[0004] The present invention provides a lifting compensation control method and a lifting system for an offshore operating vessel, which can realize accurate control of the displacement of an offshore engineering structure and has the advantages of low complexity and good resistance.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] In one aspect, the present invention provides a method for controlling lift compensation of an offshore vessel, comprising the following steps:

[0007] S1, construct a model of the barge-marine engineering structure-hydraulic servo system and obtain the state equation of the model;

[0008] S2, obtaining the actual displacement of the barge and the offshore engineering structure and the actual pressure of the rod chamber and the rodless chamber of the hydraulic cylinder;

[0009] S3, calculating the estimated displacement of the marine engineering structure and the estimated pressures of the rod chamber and the rodless chamber of the hydraulic cylinder;

[0010] S4, performing an expansion state estimation on the unknown variables of the state equation in S1 according to the errors between the actual displacement and the estimated displacement, and between the actual pressure and the estimated pressure, and calculating the internal disturbance of the hydraulic cylinder during use;

[0011] S5, performing feed-forward compensation on the internal disturbance and the external disturbance generated by the barge to obtain the actual control amount of the hydraulic servo system;

[0012] S6, inputting the actual control amount of the hydraulic servo system into the model of S1, and changing the force of the hydraulic cylinder on the marine engineering structure.

[0013] In the above-mentioned lifting compensation control method for offshore vessels, the model of the barge-marine engineering structure-hydraulic servo system in step S1 is as follows:

[0014]

[0015] Among them, m t Indicates the quality of marine engineering structures; Indicates the acceleration in the rising direction of the marine engineering structure; F tu Indicates the force exerted by the hydraulic cylinder on the marine engineering structure; F z Represents the gravity of marine engineering structures; m b Indicates the mass of the barge; Indicates the acceleration of the marine engineering structure in the descending direction; F bu Indicates the force exerted by the hydraulic cylinder on the barge; F rad Represents the wave radiation force; F res F represents the hydrostatic restoring force; wave Represents the force of waves on the barge.

[0016] In the above-mentioned lifting compensation control method for offshore vessels, the state equation of the model of the barge-marine engineering structure-hydraulic servo system is as follows:

[0017]

[0018] in, represents the first-order derivative of the first state variable; x2 represents the second state variable, i.e., the actual speed of the marine engineering structure; represents the first-order derivative of the second state variable; k represents the number of hydraulic cylinders; x3 represents the third state variable, i.e., the actual hydraulic driving force; B represents the viscous friction coefficient between the marine engineering structure and the hydraulic cylinder; Indicates the speed of the barge; represents other friction characteristics in the model; m t Indicates the quality of marine engineering structures; Fz Represents the gravity of marine engineering structures; represents the first-order derivative of the third state variable; g represents the control gain; u represents the control amount; θ represents the speed gain; represents the gain of driving force; σ represents the pressure gain; p s Indicates the oil inlet pressure of the hydraulic cylinder; A1 indicates the effective area of ​​the rodless cavity of the hydraulic cylinder; β e It represents the effective volume elastic modulus of the hydraulic oil in the hydraulic cylinder; n1 represents the constant modeling error related to internal leakage; V1 represents the volume of the rodless chamber when the hydraulic rod of the hydraulic cylinder moves; A2 represents the effective action area of ​​the rod chamber of the hydraulic cylinder; n2 represents the time-varying modeling error related to internal leakage; V2 represents the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves.

[0019] In the above-mentioned lifting compensation control method for offshore vessels, the formula for calculating the estimated displacement of the marine engineering structure in step S3 is as follows:

[0020]

[0021] Among them, m t Indicates the quality of marine engineering structures; represents the acceleration of the piston; p1 represents the pressure of the rodless chamber of the hydraulic cylinder; A1 represents the effective area of ​​the rodless chamber of the hydraulic cylinder; p2 represents the pressure of the rod chamber of the hydraulic cylinder; A2 represents the effective area of ​​the rod chamber of the hydraulic cylinder; B represents the viscous friction coefficient between the marine engineering structure and the hydraulic cylinder; Indicates the speed of the piston; Represents other friction characteristics in the model; F Z Represents the gravity of marine engineering structures.

[0022] In the above-mentioned lifting compensation control method for offshore vessels, the formula for calculating the estimated pressure of the rod chamber and the rodless chamber of the hydraulic cylinder in step S3 is as follows:

[0023]

[0024] in, represents the pressure change of the rodless chamber of the hydraulic cylinder and; Indicates that the hydraulic cylinder has a rod chamber pressure change and; β e It represents the effective bulk elastic modulus of the hydraulic oil in the hydraulic cylinder; A1 represents the effective action area of ​​the rodless cavity of the hydraulic cylinder; Indicates the speed of the piston; C ip represents the internal leakage index; p1 represents the pressure of the hydraulic cylinder without rod chamber; p2 represents the pressure of the hydraulic cylinder with rod chamber; C eprepresents the external leakage index; n1 represents the constant modeling error related to internal leakage; Q1 represents the oil inlet flow rate of the hydraulic cylinder; V1 represents the volume of the rodless chamber when the hydraulic rod of the hydraulic cylinder moves; A2 represents the effective working area of ​​the rod chamber of the hydraulic cylinder; n2 represents the time-varying modeling error related to internal leakage; Q2 represents the return oil flow rate of the hydraulic cylinder; V2 represents the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves.

[0025] In the lifting compensation control method for offshore vessels as described above, in step S4, the unknown variables of the state equation in S1 are estimated by expanding the state according to the error between the actual displacement and the estimated displacement, and the actual pressure and the estimated pressure, and the internal disturbance of the hydraulic cylinder during use is calculated as follows:

[0026]

[0027] Wherein, z1 represents the first state estimation value, that is, the displacement estimation value; represents the first-order derivative of the first state estimate; z2 represents the second state estimate, i.e., the velocity estimate; β1 represents the first gain parameter of the linear extended state observer; x1 represents the first state variable, i.e., the actual displacement of the marine engineering structure; represents the first-order derivative of the second state estimate; k represents the number of hydraulic cylinders; x3 represents the third state variable, i.e., the actual hydraulic driving force; B represents the viscous friction coefficient between the marine engineering structure and the hydraulic cylinder; m t represents the mass of the marine engineering structure; x2 represents the second state variable, i.e., the actual speed of the marine engineering structure; z 01 represents the first estimate of the expansion state; represents the speed of the barge; β2 represents the second gain parameter of the linear extended state observer; z3 represents the third state estimation value, that is, the estimation value of the hydraulic driving force; represents the first-order derivative of the third state estimate; g represents the control gain; u represents the control amount; θ represents the speed gain; represents the gain of driving force; σ represents the pressure gain; p s Indicates the oil inlet pressure of the hydraulic cylinder; z 02 represents the second estimated value of the expanded state; β3 represents the third gain parameter of the linear expanded state observer; represents the first derivative of the first estimated value of the expanded state; β4 represents the fourth gain parameter of the linear expanded state observer; represents the first-order derivative of the second estimated value of the expanded state; β5 represents the fifth gain parameter of the linear expanded state observer.

[0028] In the above-mentioned lifting compensation control method for an offshore operating vessel, the step of performing feedforward compensation on the internal disturbance and the external disturbance generated by the barge to obtain the actual control amount of the hydraulic servo system in step S5 includes:

[0029] S51, the outer-loop displacement compensation controller calculates a displacement control component according to the actual displacement of the marine engineering structure and the set expected displacement, and then compensates the first estimated value of the expansion state and the external disturbance generated by the barge by the displacement control component to obtain an expected pressure value;

[0030] S52, inputting the expected pressure value in S51 into the inner loop pressure compensation controller to obtain a pressure control component, and then using the pressure control component to compensate for the second estimated value of the expansion state and the external disturbance generated by the barge to obtain the actual control value of the hydraulic servo system.

[0031] In the above-mentioned lifting compensation control method for offshore vessels, the formula for obtaining the expected pressure value by compensating the first estimated value of the expansion state and the external disturbance generated by the barge through the displacement control component is as follows:

[0032]

[0033] in, represents the virtual pressure control quantity, i.e., the expected pressure value of the inner loop pressure compensation controller; B represents the viscous friction coefficient between the marine engineering structure and the hydraulic cylinder; x2 represents the second state variable, i.e., the actual speed of the marine engineering structure; represents the speed of the barge; z 01 represents the first estimated value of the expansion state; k represents the number of hydraulic cylinders; F z Represents the gravity of marine engineering structures; m t Indicates the quality of marine engineering structures; It represents the displacement control component obtained after the displacement error passes through the proportional link.

[0034] In the above-mentioned lifting compensation control method for offshore vessels, the formula for compensating the second estimated value of the expansion state and the external disturbance generated by the barge through the pressure control component and obtaining the actual control amount of the hydraulic cylinder is as follows:

[0035]

[0036] Wherein, u represents the control quantity, i.e., the output value of the inner loop pressure compensation controller; g represents the control gain; θ represents the speed gain; z2 represents the second state estimation value; Indicates the speed of the barge; represents the gain of the driving force; z3 represents the third state estimated value, that is, the estimated value of the hydraulic driving force; σ represents the pressure gain; p s Indicates the oil inlet pressure of the hydraulic cylinder; 02 represents the second estimation of the expansion state; k3 represents the driving force error gain; e3 represents the error between the actual pressure value and the virtual pressure control value; k 13 represents the displacement error gain in the inner loop pressure compensation controller; e1 represents the displacement tracking error; k 23 represents the speed error gain in the inner loop pressure compensation controller; e2 represents the speed tracking error.

[0037] In another aspect, the present invention provides a lifting system for an offshore vessel, comprising a plurality of hydraulic cylinders connected to a barge, the hydraulic cylinders being driven by a hydraulic servo system, and the hydraulic servo system applying any of the compensation control methods described above.

[0038] Compared with the prior art, the advantages and positive effects of the present invention are:

[0039] (1) The mechanism modeling of the barge-marine engineering structure and the hydraulic servo system was carried out, and the internal disturbance of the hydraulic cylinder during use was estimated and compensated in real time through the cascade control based on the extended state observer. The system has fewer parameters, is easy to adjust, and has good anti-disturbance effect. The external disturbance caused by the barge can also be compensated in real time, which can effectively cope with the change of load mass during the load transfer stage, improve control efficiency, reduce delay, and have high reliability.

[0040] (2) The lifting system installed on the offshore operating vessel can achieve smooth docking between the offshore engineering structure and the offshore platform pile legs. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0042] Figure 1 It is a flowchart of an embodiment of a lifting compensation control method for a marine operating vessel of the present invention;

[0043] Figure 2 It is a principle block diagram of an embodiment of a lift compensation control method for a marine operating vessel of the present invention;

[0044] Figure 3 It is a schematic diagram of a hydraulic servo system in one embodiment of a lift compensation control method for an offshore vessel of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0047] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0049] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0050] like Figure 1-Figure 3 As shown, the present application provides a lift compensation control method for an offshore operating vessel, which can take into account the disturbance caused by waves passing through a barge during the modeling stage for the load transfer stage of floating installation, and take into account the movement of the upper marine engineering structure and the barge disturbance in the piston motion equation and pressure change equation of the hydraulic system.

[0051] A method for controlling lifting compensation of an offshore operating vessel comprises the following steps:

[0052] S1, construct a model of barge-marine engineering structure-hydraulic servo system and obtain the state equation of the model.

[0053] The motion of the barge in the marine environment exhibits characteristics such as nonlinearity and uncertainty. When describing the spatial motion of the barge, the dynamic equations of the barge in the heave direction and the marine engineering structure above the barge are established, that is, the model of the marine engineering structure-hydraulic servo system-barge is as follows:

[0054]

[0055] Among them, m t Indicates the quality of marine engineering structures; Indicates the acceleration in the rising direction of the marine engineering structure; F tu Indicates the force exerted by the hydraulic cylinder on the marine engineering structure; F z Represents the gravity of marine engineering structures; m b Indicates the mass of the barge; Indicates the acceleration of the marine engineering structure in the descending direction; F bu Indicates the force exerted by the hydraulic cylinder on the barge; F rad represents the wave radiation force; F res F represents the hydrostatic restoring force; wave Represents the force of waves on the barge.

[0056] Since the hydraulic cylinder is fixed vertically on the barge, the top of the hydraulic rod of the hydraulic cylinder is connected to the offshore engineering structure through a hinge. There is a fixed collective relationship between the displacement of the hydraulic rod of the hydraulic cylinder, the displacement of the offshore engineering structure and the displacement of the barge. The relationship in terms of heave is:

[0057] x p =z t -z b ;

[0058] Among them, x p Represents the displacement of the hydraulic cylinder piston; z t Represents the displacement of the marine engineering structure in the heave direction; z b Represents the displacement of the barge in the heave direction.

[0059] In the case of single degree of freedom, the force and displacement changes of multiple hydraulic cylinders on the marine engineering structure and the barge are the same. When there are k hydraulic cylinders, the calculation formula of the force of the hydraulic cylinder on the marine engineering structure is as follows:

[0060]

[0061] Among them, F tu Indicates the force exerted by the hydraulic cylinder on the marine engineering structure; F C represents the hydraulic driving force; B represents the viscous friction coefficient between the marine engineering structure and the hydraulic cylinder; Indicates the speed of the hydraulic cylinder piston; Represents other friction characteristics in the model, including the oil friction in the hydraulic cylinder, etc.

[0062] Wave radiation force, restoring force, wave force and viscous force are all related to the shape of the barge and are the hydrodynamic characteristics of the barge. Their calculation formulas are as follows:

[0063]

[0064] Among them, F rad represents the wave radiation force; w represents the frequency of the wave; a 33 (w) represents the additional mass of the barge in the heave direction; Indicates the acceleration of the marine engineering structure in the descending direction; b 33 (w) represents the damping coefficient; Indicates the speed of the barge; F res represents the hydrostatic restoring force; k 33 (w) represents the coefficient of restitution; z b represents the displacement of the barge in the heave direction; F wave Indicates the force of waves on the barge; F wave(w) represents the impact and pressure of the wave water on the barge, which is related to the amplitude and length of the wave.

[0065] In order to more clearly describe the dynamic characteristics of the marine engineering structure-hydraulic servo system-barge and realize the precise control of the displacement of the marine engineering structure, the system variables are defined as follows: the first state variable x1, i.e. the actual displacement of the marine engineering structure, the second state variable x2, i.e. the actual speed of the marine engineering structure, the third state variable x3, i.e. the actual hydraulic driving force, and The state equation of the marine engineering structure-hydraulic servo system-barge is obtained as follows:

[0066]

[0067] in, represents the first-order derivative of the first state variable; x2 represents the second state variable, i.e., the actual speed of the marine engineering structure; represents the first-order derivative of the second state variable; k represents the number of hydraulic cylinders; x3 represents the third state variable, i.e., the actual hydraulic driving force; B represents the viscous friction coefficient between the marine engineering structure and the hydraulic cylinder; Indicates the speed of the barge; represents other friction characteristics in the model; m t Indicates the quality of marine engineering structures; F z Represents the gravity of marine engineering structures; represents the first-order derivative of the third state variable; g represents the control gain; u represents the control amount; θ represents the speed gain; represents the gain of driving force; σ represents the pressure gain; p s Indicates the oil inlet pressure of the hydraulic cylinder; A1 indicates the effective area of ​​the rodless cavity of the hydraulic cylinder; β e It represents the effective volume elastic modulus of the hydraulic oil in the hydraulic cylinder; n1 represents the constant modeling error related to internal leakage; V1 represents the volume of the rodless chamber when the hydraulic rod of the hydraulic cylinder moves; A2 represents the effective action area of ​​the rod chamber of the hydraulic cylinder; n2 represents the time-varying modeling error related to internal leakage; V2 represents the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves.

[0068] Parameters g, θ, The calculation formula of σ is as follows:

[0069]

[0070] Among them, K1 represents the oil flow gain; A1 represents the effective area of ​​the rodless cavity of the hydraulic cylinder; β e It represents the effective volume elastic modulus of the hydraulic oil in the hydraulic cylinder; V1 represents the volume of the rodless chamber when the hydraulic rod of the hydraulic cylinder moves; n represents the piston area ratio of the asymmetric hydraulic cylinder, p s It represents the oil inlet pressure of the hydraulic cylinder; s(u) represents the sign function of the servo valve switching, the servo valve is 1 on the right and -1 on the left; K2 represents the oil flow gain; A2 represents the effective working area of ​​the rod chamber of the hydraulic cylinder; V2 represents the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves.

[0071]

[0072] Among them, β e It represents the effective volume elastic modulus of the hydraulic oil in the hydraulic cylinder; A1 represents the effective working area of ​​the rodless chamber of the hydraulic cylinder; V1 represents the volume of the rodless chamber when the hydraulic rod of the hydraulic cylinder moves; A2 represents the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves; V2 represents the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves.

[0073] Where n represents the piston area ratio of the asymmetric hydraulic cylinder, β e Indicates the effective bulk elastic modulus of the hydraulic oil in the hydraulic cylinder; C ip represents the internal leakage index; V1 represents the volume of the non-rod chamber when the hydraulic rod of the hydraulic cylinder moves; A2 represents the effective action area of ​​the rod chamber of the hydraulic cylinder; V2 represents the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves; C ep Represents the external leakage index.

[0074]

[0075] Where n represents the piston area ratio of the asymmetric hydraulic cylinder, β e Indicates the effective bulk elastic modulus of the hydraulic oil in the hydraulic cylinder; C ip represents the internal leakage index; V1 represents the volume of the non-rod chamber when the hydraulic rod of the hydraulic cylinder moves; A2 represents the effective action area of ​​the rod chamber of the hydraulic cylinder; V2 represents the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves; C ep Represents the external leakage index.

[0076] For the subsequent design of the outer loop displacement controller, three assumptions are made on the system model:

[0077] (1) p1 and p2 are bounded;

[0078] (2) n1 and n2 are both bounded, and their differentials are also bounded;

[0079] (3) z t 、z b , They are all bounded.

[0080] S2, obtain the actual displacement of the barge and the offshore engineering structure and the actual pressure of the rod chamber and rodless chamber of the hydraulic cylinder in the hydraulic system, specifically:

[0081] Displacement sensors are installed on the barge and the marine engineering structure respectively, and the displacements of the barge and the marine engineering structure are obtained through the displacement sensors; the pressure values ​​in the rod cavity and the rodless cavity of the hydraulic cylinder are obtained through the pressure sensor.

[0082] S3, calculating the estimated displacement of the marine engineering structure and the estimated pressures of the rod chamber and the rodless chamber of the hydraulic cylinder.

[0083] The offshore engineering structure is fixed on the hydraulic rod of the hydraulic cylinder, and the hydraulic cylinder is installed on the barge. Therefore, the movement of the offshore engineering structure is achieved by the extension and contraction of the hydraulic rod. Therefore, the estimated displacement of the offshore engineering structure can be calculated by the displacement of the piston of the hydraulic rod of the hydraulic cylinder. According to Newton's second law, the load balance equation of the hydraulic rod piston is as follows:

[0084]

[0085] Among them, m t Indicates the quality of marine engineering structures; represents the acceleration of the piston; p1 represents the pressure of the rodless chamber of the hydraulic cylinder; A1 represents the effective area of ​​the rodless chamber of the hydraulic cylinder; p2 represents the pressure of the rod chamber of the hydraulic cylinder; A2 represents the effective area of ​​the rod chamber of the hydraulic cylinder; B represents the viscous friction coefficient between the marine engineering structure and the hydraulic cylinder; Indicates the speed of the piston; Represents other friction characteristics in the model; F z Represents the gravity of marine engineering structures.

[0086] The movement of the hydraulic cylinder piston is achieved through the pressure change of the rod chamber and the rodless chamber in the hydraulic cylinder, and the pressure change of the rod chamber and the rodless chamber is achieved through oil supply and oil return. The flow of oil supply and oil return is controlled by the hydraulic servo valve. The movement direction of the hydraulic servo valve spool is controlled by the size and direction of the control current. In the actual action process of the hydraulic servo valve, its movement can be regarded as a high-frequency process. The model of the hydraulic servo valve can be regarded as a proportional link. The formula is as follows:

[0087] x v =K axv U;

[0088] Among them, x v Indicates the valve core displacement of the hydraulic servo valve; K axv Represents the hydraulic servo valve gain; U represents the equivalent voltage output by the inner loop pressure controller.

[0089] Assuming that during the movement of the hydraulic cylinder, the oil supply pressure of the hydraulic cylinder is fixed and the return oil pressure can be approximated to zero, the dynamic switching characteristics of the hydraulic servo valve can be represented by a symbolic function, which is shown as follows:

[0090]

[0091] in, The symbolic function representing the dynamic switching characteristics of the hydraulic servo valve; x v Represents the valve core displacement of the hydraulic servo valve; where x v ≥0, the valve core of the hydraulic servo valve moves to the right, x v When <0, the valve core of the hydraulic servo valve moves to the left.

[0092] The oil inlet flow and oil return flow of the hydraulic servo valve are shown in the following formula:

[0093]

[0094] Where, Q1 represents the oil flow rate of the hydraulic cylinder; C d represents the flow coefficient; w1 represents the volume gradient of the hydraulic servo valve on the rodless chamber side; w2 represents the volume gradient of the hydraulic servo valve on the rod chamber side; ρ represents the density of the hydraulic oil in the hydraulic cylinder; x v Indicates the valve core displacement of the hydraulic servo valve; The symbolic function representing the dynamic switching characteristics of the hydraulic servo valve; p s It represents the oil inlet pressure of the hydraulic cylinder; p0 represents the oil return pressure of the hydraulic cylinder; p1 represents the pressure of the rodless chamber of the hydraulic cylinder; Q2 represents the oil return flow of the hydraulic cylinder; p2 represents the pressure of the rod chamber of the hydraulic cylinder.

[0095] Combining the model formula of the hydraulic servo valve with the oil inlet flow and oil return flow formula of the hydraulic servo valve, we get:

[0096]

[0097] Among them, Q1 represents the oil inlet flow rate of the hydraulic cylinder; K1 represents the oil inlet flow gain; U represents the equivalent voltage output by the inner ring pressure controller; Q2 represents the oil return flow rate of the hydraulic cylinder; K2 represents the oil return flow gain; The symbolic function representing the dynamic switching characteristics of the hydraulic servo valve; p s It represents the oil inlet pressure of the hydraulic cylinder; p0 represents the oil return pressure of the hydraulic cylinder; p1 represents the pressure of the rodless chamber of the hydraulic cylinder; p2 represents the pressure of the rod chamber of the hydraulic cylinder.

[0098] The calculation formulas for K1 and K2 are as follows:

[0099]

[0100] Among them, C d represents the flow coefficient; w1 represents the volume gradient of the hydraulic servo valve on the rodless chamber side; K axv represents the hydraulic servo valve gain; ρ represents the density of the hydraulic oil in the hydraulic cylinder; w2 represents the volume gradient of the hydraulic servo valve on the rod chamber side.

[0101] According to the oil inlet flow and return flow of the hydraulic servo valve and the pressure of the rod chamber and rodless chamber of the hydraulic cylinder, the formulas for the flow change of the rod chamber and the flow change of the rodless chamber are as follows:

[0102]

[0103] Among them, Q1 represents the oil flow rate of the hydraulic cylinder; A1 represents the effective area of ​​the rodless cavity of the hydraulic cylinder; Indicates the speed of the piston; C ip represents the internal leakage index; p1 represents the pressure of the hydraulic cylinder without rod chamber; p2 represents the pressure of the hydraulic cylinder with rod chamber; C ep represents the external leakage index; n1 represents the constant modeling error related to internal leakage; V1 represents the volume of the rodless chamber when the hydraulic rod of the hydraulic cylinder moves; β e Indicates the effective bulk elastic modulus of the hydraulic oil in the hydraulic cylinder; represents the pressure change of the rodless chamber of the hydraulic cylinder; Q2 represents the return oil flow of the hydraulic cylinder; A2 represents the effective area of ​​the rod chamber of the hydraulic cylinder; n2 represents the time-varying modeling error related to internal leakage; V2 represents the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves; Indicates that the hydraulic cylinder has rod chamber changes and.

[0104] The calculation formula for the volume of the rodless chamber and the volume of the rod chamber when the hydraulic rod moves is as follows:

[0105]

[0106] Where V1 represents the volume of the rodless chamber when the hydraulic rod moves; V L represents the initial volume of the rodless chamber of the hydraulic cylinder; A1 represents the effective area of ​​the rodless chamber of the hydraulic cylinder; x p represents the displacement of the hydraulic cylinder piston; V2 represents the volume of the rod chamber when the hydraulic rod moves; V R It represents the initial volume of the rod chamber of the hydraulic cylinder; A2 represents the effective working area of ​​the rod chamber of the hydraulic cylinder.

[0107] The formula for estimating the pressure of the rod chamber and rodless chamber of the hydraulic cylinder is as follows:

[0108]

[0109] in, Indicates the pressure change of the rodless chamber of the hydraulic cylinder and; Indicates that the hydraulic cylinder has a rod chamber pressure change and; β e It represents the effective bulk elastic modulus of the hydraulic oil in the hydraulic cylinder; A1 represents the effective action area of ​​the rodless cavity of the hydraulic cylinder; Indicates the speed of the piston; C ip represents the internal leakage index; p1 represents the pressure of the hydraulic cylinder without rod chamber; p2 represents the pressure of the hydraulic cylinder with rod chamber; C ep represents the external leakage index; n1 represents the constant modeling error related to internal leakage; Q1 represents the oil inlet flow rate of the hydraulic cylinder; V1 represents the volume of the rodless chamber when the hydraulic rod of the hydraulic cylinder moves; A2 represents the effective working area of ​​the rod chamber of the hydraulic cylinder; n2 represents the time-varying modeling error related to internal leakage; Q2 represents the return oil flow rate of the hydraulic cylinder; V2 represents the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves.

[0110] In the hydraulic servo system, the piston area ratio of the asymmetric hydraulic cylinder is Assumption F C =(A1p1-A2p2), F C represents the hydraulic driving force, then the pressure p2 of the rod chamber of the hydraulic cylinder and the pressure p1 of the rodless chamber and the hydraulic driving force F C It is expressed as:

[0111]

[0112] The flow rate change formula of the rod cavity and the rodless cavity can be rewritten as:

[0113]

[0114] Among them, K1 represents the oil flow gain; u represents the control amount; n represents the asymmetric hydraulic cylinder piston area ratio; p s represents the oil inlet pressure of the hydraulic cylinder; s(u) represents the sign function of the servo valve switching; F C represents the hydraulic driving force; A1 represents the effective working area of ​​the rodless chamber of the hydraulic cylinder; K2 represents the return oil flow gain.

[0115] F C To differentiate,

[0116]

[0117] Among them, A1 represents the effective action area of ​​the rodless chamber of the hydraulic cylinder; Indicates the pressure change of the rodless chamber of the hydraulic cylinder and; represents the pressure change in the rod chamber of the hydraulic cylinder; A2 represents the effective working area of ​​the rod chamber of the hydraulic cylinder.

[0118] Will Substituting into the rewritten formula of flow change of the rod cavity and the rodless cavity, we can get:

[0119]

[0120] in, Indicates the change value of hydraulic driving force; β e It represents the effective volume elastic modulus of the hydraulic oil in the hydraulic cylinder; A1 represents the effective action area of ​​the rodless cavity of the hydraulic cylinder; V1 represents the volume of the rodless cavity when the hydraulic rod of the hydraulic cylinder moves; A2 represents the effective action area of ​​the rod cavity of the hydraulic cylinder; V2 represents the volume of the rod cavity when the hydraulic rod of the hydraulic cylinder moves; represents the speed of the piston; f1 represents the working pressure term related to the change of the hydraulic driving force after sorting; f2 represents the driving force term related to the change of the hydraulic driving force after sorting; Q1 represents the oil inlet flow rate of the hydraulic cylinder; Q2 represents the oil return flow rate of the hydraulic cylinder; n1 represents the constant modeling error related to the internal leakage; n2 represents the time-varying modeling error related to the internal leakage.

[0121] The calculation formulas for f1 and f2 are as follows:

[0122]

[0123] Where f1 represents the working pressure term related to the hydraulic driving force change after sorting; f2 represents the driving force term related to the hydraulic driving force change after sorting; n represents the piston area ratio of the asymmetric hydraulic cylinder; p s Indicates the oil inlet pressure of the hydraulic cylinder; F C represents the hydraulic driving force; A1 represents the effective area of ​​the rodless chamber of the hydraulic cylinder; β e Indicates the effective bulk elastic modulus of the hydraulic oil in the hydraulic cylinder; C ip represents the internal leakage index; V1 represents the volume of the non-rod chamber when the hydraulic rod of the hydraulic cylinder moves; A2 represents the effective action area of ​​the rod chamber of the hydraulic cylinder; V2 represents the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves; C ep Represents the external leakage index.

[0124] S4, based on the error between the actual displacement and the estimated displacement, the actual pressure and the estimated pressure, the unknown variables of the state equation in S1 are estimated by expanding the state, and the internal disturbance of the hydraulic cylinder during use is calculated.

[0125] The extended state observer is an important part of the active disturbance rejection control technology. It can expand the uncertainty and disturbance terms of the model into new state variables, use the feedback mechanism to observe the expanded state, and only use the system's rated control quantity and output without requiring other state variables.

[0126] According to the state equation of marine engineering structure-hydraulic servo system-barge, for the equation Unknown variables such as n1 and n2 can obtain their real-time estimated values ​​through the linear extended state observer, and the real-time estimated values ​​are introduced into the system as feedforward compensation to compensate for the parameter uncertainty and model uncertainty of the system.

[0127] Assumptions x 01 、x 02 In the state equation of the barge-marine engineering structure-hydraulic servo system, the first state variable x1 and the third state variable x3 are known, and x1 and x3 are used to estimate the expanded state x respectively. 01 and x 02 , define z1, z2, z3 as the estimated values ​​of the system state, z 01 、z 02 is the estimated value of the expansion state, then the expansion state is estimated according to the error between the actual displacement and the estimated displacement, and the actual pressure and the estimated pressure as shown below:

[0128]

[0129] Wherein, z1 represents the first state estimation value, that is, the displacement estimation value; represents the first-order derivative of the first state estimate; z2 represents the second state estimate, i.e., the velocity estimate; β1 represents the first gain parameter of the linear extended state observer; x1 represents the first state variable, i.e., the actual displacement of the marine structure; represents the first-order derivative of the second state estimate; k represents the number of hydraulic cylinders; x3 represents the third state variable, namely the actual hydraulic driving force; B represents the viscous friction coefficient between the marine engineering structure and the hydraulic cylinder; m t represents the mass of the marine engineering structure; x2 represents the second state variable, that is, the actual speed of the marine engineering structure; z 01 represents the first estimate of the expansion state, i.e. Other friction characteristics in the model; represents the speed of the barge; β2 represents the second gain parameter of the linear extended state observer; z3 represents the third state estimation value, that is, the estimation value of the hydraulic driving force; represents the first-order derivative of the third state estimate; g represents the control gain; u represents the control amount; θ represents the speed gain; represents the gain of driving force; σ represents the pressure gain; p s Indicates the oil inlet pressure of the hydraulic cylinder; z 02 represents the second estimated value of the expanded state, that is, the disturbance caused by the error during modeling, such as the disturbance caused by n1 and n2; β3 represents the third gain parameter of the linear expanded state observer; represents the first derivative of the first estimated value of the expanded state; β4 represents the fourth gain parameter of the linear expanded state observer; represents the first-order derivative of the second estimated value of the expanded state; β5 represents the fifth gain parameter of the linear expanded state observer.

[0130] The calculation formula of the gain parameter of the linear extended state observer is as follows:

[0131]

[0132] Among them, h1 represents the time scale for observing the error between the actual value and the estimated value of the piston displacement; h2 represents the time scale for observing the error between the actual value and the estimated value of the driving force.

[0133] S5, feed-forward compensation is performed on the internal disturbance and the external disturbance generated by the barge to obtain the actual control amount of the hydraulic cylinder.

[0134] In order to control the displacement of marine engineering structures, it is necessary to consider the dynamic changes of pressure. Therefore, a controller based on the cascade control strategy of the extended state observer is designed. The controller includes an outer-loop displacement controller and an inner-loop pressure controller.

[0135] The steps to compensate for internal disturbances as well as external disturbances generated by the barge include:

[0136] S51, the outer loop displacement compensation controller calculates the displacement control component according to the actual displacement of the marine engineering structure and the set expected displacement, and then compensates the first estimated value of the expansion state and the external disturbance generated by the barge through the displacement control component to obtain the expected pressure value.

[0137] The expected displacement is the motion path of the marine engineering structure calculated based on the barge motion to achieve a stable state.

[0138] The formula to obtain the desired pressure value is as follows:

[0139]

[0140] in, represents the virtual pressure control amount, that is, the expected pressure value of the inner loop pressure compensation controller; B represents the viscous friction coefficient between the marine engineering structure and the hydraulic cylinder; x2 represents the second state variable, that is, the actual speed of the marine engineering structure; represents the speed of the barge; z 01 represents the first estimated value of the expansion state; k represents the number of hydraulic cylinders; F z Represents the gravity of marine engineering structures; m t Indicates the quality of marine engineering structures; It represents the displacement control component obtained after the displacement error passes through the proportional link.

[0141] The calculation formula of the displacement control component is as follows:

[0142]

[0143] in, represents the displacement control component; k1 represents the displacement error gain; e1 represents the displacement tracking error; k2 represents the speed error gain; e2 represents the speed tracking error.

[0144] The calculation formulas for displacement tracking error e1 and velocity tracking error e2 are as follows:

[0145]

[0146] Where x1 represents the first state variable, i.e., the actual displacement of the offshore structure; x d represents the set displacement signal; x2 represents the second state variable, that is, the actual speed of the marine engineering structure; z2 represents the second state estimation value, that is, the speed estimation value.

[0147] The ideal pressure value of the outer ring displacement controller is Assumptions According to the state equation of marine engineering structure-hydraulic servo system-barge, the output equation of the hydraulic servo system is set as:

[0148]

[0149] in, represents the first-order derivative of the third state variable; g represents the control gain; u represents the control amount; θ represents the speed gain; x2 represents the second state variable, Indicates the speed of the barge; represents the gain of driving force; σ represents the pressure gain; p s represents the oil pressure of the hydraulic cylinder; A1 represents the effective area of ​​the rodless cavity of the hydraulic cylinder, β e It represents the effective volume elastic modulus of the hydraulic oil in the hydraulic cylinder; n1 represents the constant modeling error related to internal leakage; V1 represents the volume of the rodless chamber when the hydraulic rod of the hydraulic cylinder moves; A2 represents the effective action area of ​​the rod chamber of the hydraulic cylinder; n2 represents the time-varying modeling error related to internal leakage; V2 represents the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves.

[0150] S52, input the expected pressure value in S5 into the inner loop pressure compensation controller to obtain a pressure control component, and then use the pressure control component to compensate for the second estimated value of the expansion state and the external disturbance generated by the barge to obtain the actual control amount of the hydraulic cylinder.

[0151] Finally, the formula for compensating the second estimated value of the expansion state and the external disturbance generated by the barge through the pressure control component and obtaining the actual control amount of the hydraulic cylinder is as follows:

[0152]

[0153] Among them, u represents, that is, the output value of the inner loop pressure compensation controller, which is expressed as the current output of the control hydraulic valve; g represents the control gain; θ represents the speed gain; z2 represents the second state estimation value; Indicates the speed of the barge; represents the gain of driving force; z3 represents the third state estimation value; σ represents the pressure gain; p s Indicates the oil inlet pressure of the hydraulic cylinder; 02 represents the second estimation of the expansion state; k3 represents the driving force error gain; e3 represents the error between the actual pressure value and the virtual pressure control value; k 13 represents the displacement error gain in the inner loop pressure compensation controller; e1 represents the displacement tracking error; k 23 represents the speed error gain in the inner loop pressure compensation controller; e2 represents the speed tracking error.

[0154] S6, inputs the actual control quantity of the hydraulic servo system into the model of S1, controls the flow of hydraulic oil in and out of the hydraulic cylinder, thereby changing the pressure of the rod chamber and the rodless chamber of the hydraulic cylinder, thereby changing the force of the hydraulic cylinder on the marine engineering structure.

[0155] The present application also provides a lifting system for an offshore vessel, comprising a plurality of hydraulic cylinders connected to a barge, the hydraulic cylinders being driven by a hydraulic servo system, and the hydraulic servo system applying the compensation control method as described above.

[0156] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0157] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions claimed to be protected by the present invention.

Claims

1. A method for controlling lifting compensation of an offshore operating vessel, characterized in that: The following steps are involved: S1, construct a model of the barge-marine engineering structure-hydraulic servo system and obtain the state equation of the model; The model of the barge-marine engineering structure-hydraulic servo system is as follows: ； in, Indicates the quality of marine engineering structures; Indicates the acceleration in the rising direction of the marine engineering structure; Indicates the force exerted by the hydraulic cylinder on the marine engineering structure; Represents the gravity of marine engineering structures; Indicates the mass of the barge; Indicates the acceleration in the descending direction of the marine engineering structure; Indicates the force exerted by the hydraulic cylinder on the barge; represents the wave radiation force; represents the hydrostatic restoring force; represents the force of waves on the barge; The state equation of the model of the barge-marine engineering structure-hydraulic servo system is as follows: ； in, represents the first derivative of the first state variable; represents the second state variable, i.e., the actual speed of the marine engineering structure; represents the first derivative of the second state variable; Indicates the number of hydraulic cylinders; represents the third state variable, i.e., the actual hydraulic driving force; Represents the viscous friction coefficient between the marine engineering structure and the hydraulic cylinder; Indicates the speed of the barge; Represents other friction characteristics in the model; Indicates the quality of marine engineering structures; Represents the gravity of marine engineering structures; represents the first derivative of the third state variable; represents the control gain; Indicates the control quantity; Indicates speed gain; Indicates the gain of driving force; represents the pressure gain; Indicates the oil inlet pressure of the hydraulic cylinder; It represents the effective working area of ​​the rodless chamber of the hydraulic cylinder; Indicates the effective bulk elastic modulus of the hydraulic oil in the hydraulic cylinder; represents the constant modeling error associated with internal leakage; It indicates the volume of the rodless chamber when the hydraulic rod of the hydraulic cylinder moves; It indicates the effective working area of ​​the rod cavity of the hydraulic cylinder; represents the time-varying modeling error associated with endoleakage; It indicates the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves; S2, obtaining the actual displacement of the barge and the offshore engineering structure and the actual pressure of the rod chamber and the rodless chamber of the hydraulic cylinder; S3, calculating the estimated displacement of the marine engineering structure and the estimated pressures of the rod chamber and the rodless chamber of the hydraulic cylinder; The formula for calculating the estimated displacement of the marine engineering structure is as follows: ； in, Indicates the quality of marine engineering structures; represents the acceleration of the piston; Indicates the pressure of the rodless chamber of the hydraulic cylinder; Indicates the effective working area of ​​the rodless chamber of the hydraulic cylinder; Indicates the pressure of the rod chamber of the hydraulic cylinder; It indicates the effective working area of ​​the rod cavity of the hydraulic cylinder; Represents the viscous friction coefficient between the marine engineering structure and the hydraulic cylinder; Indicates the speed of the piston; Represents other friction characteristics in the model; Represents the gravity of marine engineering structures; The formula for calculating the estimated pressure of the rod chamber and the rodless chamber of the hydraulic cylinder is as follows: ； in, represents the pressure change of the rodless chamber of the hydraulic cylinder and; Indicates that the hydraulic cylinder has rod chamber pressure changes and; Indicates the effective bulk elastic modulus of the hydraulic oil in the hydraulic cylinder; Indicates the effective working area of ​​the rodless chamber of the hydraulic cylinder; Indicates the speed of the piston; represents the internal leakage index; Indicates the pressure of the rodless chamber of the hydraulic cylinder; Indicates the pressure of the rod chamber of the hydraulic cylinder; It represents the external leakage index; represents the constant modeling error associated with internal leakage; Indicates the oil flow rate of the hydraulic cylinder; It indicates the volume of the rodless chamber when the hydraulic rod of the hydraulic cylinder moves; It indicates the effective working area of ​​the rod cavity of the hydraulic cylinder; represents the time-varying modeling error associated with endoleakage; Indicates the return oil flow of the hydraulic cylinder; It indicates the volume of the rod chamber when the hydraulic rod of the hydraulic cylinder moves; S4, performing an expansion state estimation on the unknown variables of the state equation in S1 according to the error between the actual displacement and the estimated displacement, and the actual pressure and the estimated pressure, and calculating the internal disturbance of the hydraulic cylinder during use, as shown below: ； in, represents the first state estimation value, that is, the displacement estimation value; represents the first derivative of the first state estimate; represents the second state estimation value, i.e., the speed estimation value; represents the first gain parameter of the linear extended state observer; represents the first state variable, i.e., the actual displacement of the marine engineering structure; represents the first derivative of the second state estimate; Indicates the number of hydraulic cylinders; represents the third state variable, i.e., the actual hydraulic driving force; represents the viscous friction coefficient between the marine engineering structure and the hydraulic cylinder; Indicates the quality of marine engineering structures; represents the second state variable, i.e., the actual speed of the marine engineering structure; represents the first estimate of the expansion state; Indicates the speed of the barge; represents the second gain parameter of the linear extended state observer; represents a third state estimation value, i.e., an estimation value of the hydraulic driving force; represents the first derivative of the third state estimate; represents the control gain; Indicates the control quantity; Indicates speed gain; Indicates the gain of driving force; represents the pressure gain; Indicates the oil inlet pressure of the hydraulic cylinder; a second estimate representing the expansion state; represents the third gain parameter of the linear extended state observer; The first derivative representing the first estimate of the expansion state; represents the fourth gain parameter of the linear extended state observer; a first derivative of a second estimate representing the expansion state; represents the fifth gain parameter of the linear extended state observer; S5, performing feed-forward compensation on the internal disturbance and the external disturbance generated by the barge to obtain the actual control amount of the hydraulic servo system, as shown below: S51, the outer loop displacement compensation controller calculates a displacement control component according to the actual displacement of the marine engineering structure and the set expected displacement, and then compensates the first estimated value of the expansion state and the external disturbance generated by the barge by the displacement control component to obtain an expected pressure value; The formula to obtain the desired pressure value is as follows: ； in, Indicates setting the virtual pressure control amount, that is, the expected pressure value of the inner loop pressure compensation controller; Represents the viscous friction coefficient between the marine engineering structure and the hydraulic cylinder; represents the second state variable, i.e., the actual speed of the marine engineering structure; Indicates the speed of the barge; represents the first estimate of the expansion state; Indicates the number of hydraulic cylinders; Represents the gravity of marine engineering structures; Indicates the quality of marine engineering structures; It represents the displacement control component obtained after the displacement error passes through the proportional link; S52, inputting the expected pressure value in S51 into an inner loop pressure compensation controller to obtain a pressure control component, and then compensating the second estimated value of the expansion state and the external disturbance generated by the barge through the pressure control component to obtain an actual control amount of the hydraulic servo system; The formula for obtaining the actual control amount is as follows: ； in, Represents the control quantity, that is, the output value of the inner loop pressure compensation controller; represents the control gain; Indicates speed gain; represents the second state estimation value, i.e., the speed estimation value; Indicates the speed of the barge; Indicates the gain of driving force; represents a third state estimation value, i.e., an estimation value of the hydraulic driving force; represents the pressure gain; Indicates the oil inlet pressure of the hydraulic cylinder; a second estimator representing the expansion state; represents the driving force error gain; Indicates the error between the actual pressure value and the virtual pressure control value; represents the displacement error gain in the inner loop pressure compensation controller; represents the displacement tracking error; Represents the speed error gain in the inner loop pressure compensation controller; Indicates the speed tracking error; S6, inputting the actual control amount of the hydraulic servo system into the model of S1, and changing the force of the hydraulic cylinder on the marine engineering structure.

2. A lifting system for an offshore vessel, characterized in that: It comprises a plurality of groups of hydraulic cylinders, which are connected to the barge and driven by a hydraulic servo system, and the hydraulic servo system applies the compensation control method as claimed in claim 1.

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