Method and system for calculating influence of dynamic response of separation support device and buffer coupling device on ship pose in floating support installation process

Abstract

The invention relates to the technical field of ocean engineering operation motion modeling and control, and particularly discloses a method and a system for calculating influence of dynamic response of a separation supporting device and a buffer coupling device on a ship pose in a floating support installation process. The method comprises the following steps: acquiring initial position information of a separation support device and a buffer coupling device at a previous moment; acquiring vertical position and attitude information of the dynamic positioning ship and the upper module; calculating the supporting force of the separation supporting device and the buffer coupling device at the current moment; calculating the vertical position and attitude information of the upper module and the dynamic positioning ship at the current moment based on the supporting force and the external ballast water load; outputting relevant parameters and judging whether the installation is completed or not. According to the method, a multi-degree-of-freedom coupling dynamic model is constructed, high-precision real-time simulation of device dynamic response and ship motion attitude in the continuous unsteady-state load transfer process is realized, key parameter monitoring and risk early warning are provided for floating mounting operation, and the operation safety and efficiency are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of marine engineering operation motion modeling and control, and particularly relates to a method and system for calculating the influence of the dynamic response of a separation support device and a buffer coupling device on the position of a ship during a float-over installation process. BACKGROUND

[0002] An offshore platform is a key facility for offshore oil and gas development. There are various methods for installing offshore platforms, and the common methods are hoisting and float-over installation. The float-over installation method is widely used at present because it is suitable for super large modules, reduces the dependence on expensive heavy lift vessels, reduces offshore operation time and risk, and is suitable for complex sea conditions and shallow water areas. The core feature of float-over installation is to use a floating transport ship or barge to transport the platform upper block to the installation location, and to make it slowly sink by adjusting the ballast water, and finally to accurately dock the upper block to the installed support structure.

[0003] During the actual operation process of offshore platform installation, due to the influence of the offshore environment and the operation load, it is a very tedious engineering project to realize the DP float-over installation of the offshore upper block. The float-over installation usually includes five stages of loading, transportation, entering the ship, load transfer and unloading. The load transfer is the most complex and dangerous stage in the entire float-over installation. In order to ensure the safe and smooth progress of the float-over installation operation, it is necessary to model and simulate the dynamic and kinematic characteristics during the offshore float-over installation process, especially the dynamic characteristics during the load transfer process, to identify unknown operation risk points, improve operation efficiency, and reduce operation cost. In the present application, a marine environment model, a six-degree-of-freedom kinematic model of a semi-submersible ship, a DP model of a semi-submersible ship, a ballast system model, an upper block dynamic model, a platform lower structure model, a separation support device (DSU) dynamic model, and a docking coupling buffer device (LMU) dynamic model are established according to the operation characteristics of the DP float-over installation process of the offshore platform upper block. A method for calculating the dynamic response of the separation support device and the buffer coupling device during the float-over installation process is proposed, and a DP float-over installation operation dynamic simulation system reflecting the continuous non-steady state load transfer process is constructed. The float-over installation operation of the offshore platform has important engineering application value and practical significance. SUMMARY

[0004] The present application establishes a 12-degree-of-freedom kinematic and dynamic model of the offshore platform upper block-DP semi-submersible operation ship-fixed offshore platform lower structure, proposes a method and system for calculating the influence of the dynamic response of the separation support device and the buffer coupling device on the position of the ship during the float-over installation process, and finally constructs a DP float-over installation operation simulation system with continuous non-steady state load transfer characteristics.

[0005] The application provides a method and system for calculating the influence of the dynamic response of a separation support device and a buffer coupling device on the position of a ship during a float-over installation process.

[0006] A method for calculating the influence of the dynamic response of a separation support device and a buffer coupling device on the position of a ship during a float-over installation process, comprising the following steps:

[0007] Obtaining initial position information of the separation support device and initial position information of the buffer coupling device; setting an external ballast water load and a calculation period; starting iterative calculation, and performing the following steps in each iteration process:

[0008] Step 1: calculating the support force of the separation support device and the support force of the buffer coupling device at the current time according to the vertical position information of the dynamic positioning ship, the vertical position information of the upper block, the attitude information of the dynamic positioning ship, the attitude information of the upper block, the initial position information of the separation support device and the initial position information of the buffer coupling device at the previous time.

[0009] Step 2: calculating the vertical position and attitude information of the upper block and the vertical position and attitude information of the dynamic positioning ship at the current time according to the support force of the separation support device, the support force of the buffer coupling device and the external ballast water load at the current time.

[0010] Step 3: outputting the vertical position and attitude information of the upper block, the vertical position and attitude information of the dynamic positioning ship, the force of the separation device and the docking buffer device, and the equivalent compression amount of the separation device and the docking buffer device at the current time; determining whether the float-over and load transfer process is completed installation, if yes, ending the process, if not, returning to step 1.

[0011] Further, the buffer coupling device in step 1 comprises a pile leg tip of the upper block and a conical receiver of a lower guide pipe support; and the initial position information of the buffer coupling device is the initial position information of the conical receiver of the lower guide pipe support.

[0012] Further, the support force calculation method of the buffer coupling device at the current time in step 1 comprises:

[0013] Step 1.1.1: calculating the compression amount of the buffer coupling device at the current time

[0014]

[0015] Wherein, q is the index of the buffer coupling device, t is the index of the current time, is the vertical position of the upper block at the previous time, D0 is the vertical position of the platform lower guide pipe support, (x q ,y q) is the initial position information of the conical receiver of the lower jacket, and is the attitude angle of the upper block at the last time.

[0016] Step 1.1.2: According to the compression amount of the buffer coupling device at the current time, the compression speed of the buffer coupling device at the current time is calculated

[0017]

[0018] Where T is the calculation period.

[0019] Step 1.1.3: According to the compression amount and compression speed of the buffer coupling device at the current time, the support force of the buffer coupling device at the current time is calculated

[0020]

[0021] Where k2 is the equivalent stiffness coefficient of the buffer coupling device, and c2 is the equivalent damping coefficient of the buffer coupling device; Where F is the pressure received by the rubber; Where m is the system mass, δ q is the amplitude attenuation rate of the buffer coupling device; Where, and are the initial and nth period amplitudes of the buffer coupling device, respectively.

[0022] Further, the support force calculation method of the separation support device at the current time in step 1 specifically comprises:

[0023] Step 1.2.1: Calculate the displacement change amount of the separation support device at the current time

[0024]

[0025] Where l is the separation support device index, (x l ,y l ) is the initial position information of the separation support device, and is the attitude angle of the dynamically positioned ship at the last time.

[0026] Step 1.2.2: In combination with the displacement change amount of the separation support device at the current time, the compression amount of the separation support device at the current time is calculated

[0027]

[0028] Where, vertical position of the topside at the previous time step, vertical position of the dynamically positioned vessel at the previous time step, and attitude angle of the topside at the previous time step.

[0029] Step 1.2.3: Calculate the compression velocity of the separation support device at the current time step according to the compression amount of the separation support device at the current time step

[0030]

[0031] wherein T is the calculation period.

[0032] Step 1.2.4: Calculate the support force of the separation support device at the current time step according to the compression amount and the compression velocity of the separation support device at the current time step

[0033]

[0034] wherein k1 is the equivalent stiffness coefficient of the separation support device, and c1 is the equivalent damping coefficient of the separation support device; wherein F is the pressure received by the rubber; wherein m is the system mass, δ l is the amplitude attenuation rate of the separation support device; wherein, and are the initial and the n-th cycle amplitudes of the separation support device, respectively.

[0035] Further, the method for calculating the vertical position and attitude information of the topside at the current time step in step 2 comprises:

[0036]

[0037] wherein F u (t) is the external load received by the topside at the current time step, is the position attitude angle of the topside at the current time step, is the velocity angle of the topside at the current time step, is the velocity of the topside at the current time step, M u (t) is the time-varying mass matrix of the topside at the current time step, C u is the damping matrix of the topside, and K u is the stiffness matrix of the topside. wherein is the position information of the topside at the current time step, is the attitude information of the topside at the current time step.

[0038] Further, the method for calculating the vertical position and attitude information of the dynamically positioned ship at the current time in step 2 comprises:

[0039]

[0040] Wherein, F s (t) is the external load received by the dynamically positioned ship at the current time, is the position and attitude angle of the dynamically positioned ship at the current time, is the speed angle of the dynamically positioned ship at the current time, is the speed of the dynamically positioned ship at the current time, M s (t) is the time-varying mass matrix of the dynamically positioned ship at the current time; Wherein ε is the external ballast water load; Wherein is the position information of the dynamically positioned ship at the current time, is the attitude information of the dynamically positioned ship at the current time.

[0041] A computer device / system, comprising a memory, a processor and a computer program stored on the memory, wherein the processor executes the computer program to realize the steps of the method.

[0042] A computer readable storage medium, which stores a computer program / instruction, wherein the computer program / instruction is executed by a processor to realize the steps of the method.

[0043] A computer program product, comprising a computer program / instruction, wherein the computer program / instruction is executed by a processor to realize the steps of the method.

[0044] The beneficial effects of the present application are:

[0045] A 12-degree-of-freedom kinematics and dynamics model of a marine platform topside-DP semi-submersible operation ship-fixed marine platform substructure is constructed, and the dynamic response of the LMU / DSU device in the continuous non-steady load transfer process, the dynamic response characteristics of the DP semi-submersible operation ship and the dynamic response characteristics of the topside are analyzed. The coupling effect in the dynamic installation process can be simulated in real time with high precision, the stress change and the vertical motion response characteristics of the LMU and the DSU are output in real time, the key parameters are visualized for monitoring and risk warning for the floating installation command decision maker, the safety of offshore operation is improved, the dependence on physical test is reduced, the cost and construction period are reduced, and the application value and practical significance are important in engineering. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 It is a floating installation step diagram of the present application.

[0047] Figure 2 Load transfer process diagram of the present application.

[0048] Figure 3 Load transfer 12-DOF coupling characteristic diagram of the embodiment of the present application.

[0049] Figure 4 Load transfer process diagram of the present application.

[0050] Figure 5 Separation device DSU stress curve diagram in the float-over installation load transfer process of the embodiment of the present application.

[0051] Figure 6 Coupling device LMU stress curve diagram in the float-over installation load transfer process of the embodiment of the present application.

[0052] Figure 7 Separation device DSU vertical stiffness displacement curve diagram in the float-over installation load transfer process of the embodiment of the present application.

[0053] Figure 8 Coupling device LMU vertical stiffness displacement curve diagram in the float-over installation load transfer process of the embodiment of the present application. DETAILED DESCRIPTION

[0054] The following will be described in conjunction with the accompanying Figure 4 The present application is further described.

[0055] A method for calculating the influence of the dynamic response of a separation support device and a buffer coupling device in a float-over installation process on the position of a ship according to the present application, comprising the following steps:

[0056] Obtaining initial position information of the separation support device and initial position information of the buffer coupling device; setting external ballast water load and calculation period; starting iteration calculation, and performing the following steps in each iteration process.

[0057] Step 1: calculating the support force of the separation support device and the support force of the buffer coupling device at the current time according to the vertical position information of the dynamically positioned ship, the vertical position information of the upper block, the attitude information of the dynamically positioned ship, the attitude information of the upper block, the initial position information of the separation support device and the initial position information of the buffer coupling device at the last time.

[0058] The buffer coupling device comprises a pile leg tip of the upper block and a conical receiver of the lower guide pipe rack; the initial position information of the buffer coupling device is the initial position information of the conical receiver of the lower guide pipe rack.

[0059] The support force calculation method of the buffer coupling device at the current time specifically comprises:

[0060] Step 1.1.1: Calculate the compression amount of the buffer coupling device at the current time

[0061]

[0062] wherein q is the buffer coupling device index, t is the current time index, is the vertical position of the upper block at the previous time, D0 is the vertical position of the platform lower jacket, (x q ,y q ) is the initial position information of the conical receiver of the lower jacket, and is the attitude angle of the upper block at the previous time.

[0063] Step 1.1.2: Calculate the compression speed of the buffer coupling device at the current time according to the compression amount of the buffer coupling device at the current time

[0064]

[0065] wherein T is the calculation period.

[0066] Step 1.1.3: Calculate the support force of the buffer coupling device at the current time according to the compression amount and the compression speed of the buffer coupling device at the current time

[0067]

[0068] wherein k2 is the equivalent stiffness coefficient of the buffer coupling device, c2 is the equivalent damping coefficient of the buffer coupling device; wherein F is the pressure received by the rubber; wherein m is the system mass, δ q is the amplitude attenuation rate of the buffer coupling device; wherein, and are the initial and the n-th period amplitudes of the buffer coupling device, respectively.

[0069] The support force calculation method of the current time separation support device specifically includes:

[0070] Step 1.2.1: Calculate the displacement change amount of the separation support device at the current time

[0071]

[0072] wherein l is the separation support device index, (x l ,y l ) is the initial position information of the separation support device, and is the attitude angle of the upper block at the previous time.

[0073] Step 1.2.2: combining the displacement change amount of the separation support device at the current time, the compression amount of the separation support device at the current time is calculated

[0074]

[0075] wherein, is the vertical position of the upper block at the previous time, is the vertical position of the dynamically positioned ship at the previous time, and is the attitude angle of the upper block at the previous time.

[0076] Step 1.2.3: according to the compression amount of the separation support device at the current time, the compression speed of the separation support device at the current time is calculated

[0077]

[0078] wherein, T is the calculation period.

[0079] Step 1.2.4: according to the compression amount and the compression speed of the separation support device at the current time, the support force of the separation support device at the current time is calculated

[0080]

[0081] wherein, k1 is the equivalent stiffness coefficient of the separation support device, and c1 is the equivalent damping coefficient of the separation support device; wherein F is the pressure received by the rubber; wherein m is the system mass, δ l is the amplitude attenuation rate of the separation support device; wherein, and are the initial and the n-th cycle amplitudes of the separation support device, respectively.

[0082] Step 2: according to the support force of the separation support device at the current time, the support force of the buffer coupling device, and the external ballast water load, the vertical position and attitude information of the upper block at the current time and the vertical position and attitude information of the dynamically positioned ship at the current time are calculated respectively.

[0083] The method for calculating the vertical position and attitude information of the upper block at the current time comprises:

[0084]

[0085] wherein, F u(t) is the external load on the upper block at the current time, is the position and attitude angle of the upper block at the current time, is the velocity angle of the upper block at the current time, is the velocity of the upper block at the current time, M u (t) is the time-varying mass matrix of the upper block at the current time, C u is the damping matrix of the upper block, K u is the stiffness matrix of the upper block; is the position information of the upper block at the current time, is the attitude information of the upper block at the current time.

[0086] The method for calculating the vertical position and attitude information of the dynamically positioned ship at the current time comprises:

[0087]

[0088] wherein F s (t) is the external load on the dynamically positioned ship at the current time, is the position and attitude angle of the dynamically positioned ship at the current time, is the velocity angle of the dynamically positioned ship at the current time, is the velocity of the dynamically positioned ship at the current time, M s (t) is the time-varying mass matrix of the dynamically positioned ship at the current time; wherein ε is the external ballast water load; is the position information of the dynamically positioned ship at the current time, is the attitude information of the dynamically positioned ship at the current time.

[0089] Step 3: output the vertical position and attitude information of the upper block at the current time, the vertical position and attitude information of the dynamically positioned ship, the force on the separation device and the docking buffer device, and the equivalent compression amount of the separation device and the docking buffer device; determine whether the float and load transfer process is completed installation, if completed, end the process, if not completed installation, return to step 1.

[0090] Embodiment

[0091] In view of the problem that the dynamic and kinematic responses of the buffer device cannot be observed in real time in the existing fixed offshore platform dynamic positioning float-over installation simulation test software, a simulation method for calculating the dynamic responses of the separation support device and the buffer coupling device during the float-over installation process is proposed, and a coupling dynamic model of the DP float-over installation process of the offshore platform upper block is designed to realize real-time monitoring of the force state of the buffer device DSU and the coupling device LMU during the installation process. ​​

[0092] This embodiment is based on the load transfer 12 degrees of freedom coupling characteristics, as Figure 3 The multi-body dynamics model of the topside module-DP semi-submersible operation ship-fixed offshore platform substructure coupling system and the parametric mechanical model of the LMU / DSU device are constructed as shown, the displacement, velocity and force of the buffer device are calculated by real-time acquisition of the dynamic positioning ship motion attitude data, and the real-time force and displacement curves are output.

[0093] The first step is to construct the dynamic and kinematic model of the dynamic positioning ship, which includes the following steps: Figure 4

[0094] 1. Establish the time-varying mass matrix of the dynamic positioning ship

[0095] M(t i )=M0+ΔM(t i )

[0096] Wherein, is the matrix of the additional mass at m(t) located at the coordinate system (x, y, z)

[0097] 2. Establish the dynamic model of the dynamic positioning ship

[0098] M U (t i )X U +C U X U +K U X U =F U (t)

[0099] In the formula: X U =[x U y U z U θ Ux θ Uy θ Uz ] T represent the vector form of the topside module kinematic model

[0100] The second step is to construct the dynamic and kinematic model of the topside module, which includes the following steps:

[0101] 1. Establish the time-varying mass matrix of the topside module:

[0102] M(t i )=M0+ΔM(t i )

[0103] Wherein, is the matrix of the additional mass at m(t) located at the coordinate system (x, y, z) ​

[0104] 2. Establish the upper block dynamics model:

[0105] M U (t i )X U +C U X U +K U X U =F U (t)

[0106] Where: X U =[x U y U z U θ Ux θ Uy θ Uz ] T represents the vector form of the upper block kinematics model

[0107] Thirdly, establish the buffer device dynamics and kinematics model, the specific steps include:

[0108] 1. Calculate the displacement change of LMU / DSU

[0109] D p =-x l sinθ-y l sinφ

[0110] Where: x l represents the initial longitudinal coordinate of the buffer device, y l represents the initial transverse coordinate of the buffer device, θ, φ represents the attitude angle of the ship.

[0111] 2. Calculate the compression amount of LMU / DSU, the calculation method is as follows:

[0112] Δu=-(x l sinθ0+y l sinφ0)+D0-D-D p

[0113] Where: x l represents the initial longitudinal coordinate of the DSU, y l represents the initial transverse coordinate of the DSU, θ0, φ0 represents the attitude angle of the upper block, D0 represents the vertical position of the upper block, D represents the vertical position of the construction ship.

[0114] 3. Calculate the compression speed of LMU / DSU, the calculation method is as follows:

[0115]

[0116] Where: T represents the calculation period

[0117] 4. The LMU and DSU are equivalent to a spring-damping system, whose mathematical model is:

[0118]

[0119] In the formula: represents the equivalent stiffness, represents the equivalent damping coefficient, represents the amplitude attenuation rate, A0, A n are the initial and the n-th cycle amplitudes, respectively.

[0120] Fourthly, the upper block dynamics and kinematics model and the buffer device dynamics and kinematics model in the second and third steps are packaged as a dynamic link library, and a dynamic positioning simulator is called to realize the transmission of load and position information.

[0121] Fifthly, the vertical position and attitude data of the dynamically positioned ship at time t-1 are read as the input of the upper block dynamic link library.

[0122] Sixthly, the four separated support device DSU support forces at time t-1 are calculated and output to the upper block dynamics calculation module.

[0123] Seventhly, the position information of the jacket platform at time t-1 is transmitted to the support force calculation module of the spudcan.

[0124] Eighthly, the vertical motion information of the semi-submersible platform upper block at time t-1 is transmitted to the support force calculation module of the spudcan.

[0125] Ninthly, the support force of the spudcan is calculated and input to the upper block dynamics model.

[0126] Tenthly, the motion and attitude of the upper block vertical plane are calculated.

[0127] Eleventhly, as Figures 5 to 8 , the support forces of the four separated support devices DSU, the support forces of the eight spudcans of the upper block, and the motion and attitude of the upper block vertical plane are output.

[0128] Twelfthly, the pressure of the four separated support devices DSU output by the upper block dynamic link library is transmitted to the dynamically positioned ship.

[0129] Thirteenthly, the external ballast water simulation load is input.

[0130] Fourteenthly, the dynamically positioned ship is operated.

[0131] The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for calculating the influence of the dynamic response of a decoupling support device and a cushioning coupling device on the ship's position during a float-on installation process, characterized in that The method comprises the following steps: obtaining initial position information of the separation support device and initial position information of the buffer coupling device; setting an external ballast water load and a calculation period; starting an iterative calculation, and performing the following steps in each iteration process: Step 1: calculating the support force of the separation support device and the support force of the buffer coupling device at the current time according to the vertical position information of the dynamically positioned ship, the vertical position information of the topside, the attitude information of the dynamically positioned ship, the attitude information of the topside, the initial position information of the separation support device and the initial position information of the buffer coupling device at the previous time; Step 2: calculating the vertical position and attitude information of the topside and the vertical position and attitude information of the dynamically positioned ship at the current time according to the support force of the separation support device, the support force of the buffer coupling device and the external ballast water load at the current time; Step 3: outputting the vertical position and attitude information of the topside, the vertical position and attitude information of the dynamically positioned ship, the force of the separation device and the buffer coupling device, and the equivalent compression amount of the separation device and the buffer coupling device at the current time; determining whether the floatation and load transfer process is completed for installation, and if so, ending the process, and if not, returning to Step 1.

2. The method of claim 1, wherein: The buffer coupling device comprises a pile leg tip of the topside and a conical receiver of the lower jacket; and the initial position information of the buffer coupling device is the initial position information of the conical receiver of the lower jacket.

3. The method of claim 2, wherein, The method for calculating the support force of the buffer coupling device at the current time in Step 1 specifically comprises: Step 1.1.1: Calculate the amount of compression of the buffer coupling device at the current time wherein q is the index of the cushioning coupling device, t is the index of the current time, is the vertical position of the upper block at the previous time, D0 is the vertical position of the platform lower jacket, (x q ,y q ) is the initial position information of the conical receiver of the lower jacket, and is the attitude angle of the upper block at the previous time; Step 1.1.2: Calculate the compression speed of the buffer coupling device at the current time according to the compression amount of the buffer coupling device at the current time wherein T is the calculation period; Step 1.1.3: According to the compression amount and compression speed of the buffer coupling device at the current time, calculate the support force of the buffer coupling device at the current time Wherein k2 is the equivalent stiffness coefficient of the buffer coupling device, c2 is the equivalent damping coefficient of the buffer coupling device; Wherein F is the pressure received by the rubber; Wherein m is the system mass, δ q is the amplitude attenuation rate of the buffer coupling device; Wherein, And are the initial and the n-th cycle amplitudes of the buffer coupling device, respectively.

4. The method of claim 3, wherein, The method for calculating the support force of the separation support device at the current time in Step 1 specifically comprises: Step 1.2.1: Calculate the displacement change amount of the separation support device at the current time wherein, l is the index of the separation support device, (x l ,y l ) is the initial position information of the separation support device, and is the attitude angle of the dynamically positioned ship at the previous time. Step 1.2.2: combine the displacement change amount of the separation support device at the current time with the compression amount of the separation support device at the current time wherein, is the vertical position of the upper block at the previous time instant, is the vertical position of the dynamically positioned vessel at the previous time instant, and is the attitude angle of the upper block at the previous time instant. Step 1.2.3: Separating the compression amount of the support device according to the current time, calculating the compression speed of the support device at the current time wherein T is the calculation period; Step 1.2.4: Separating the compression amount and compression speed of the support device according to the current time, and calculating the support force of the support device at the current time Wherein, k1 is the equivalent stiffness coefficient of the separation support device, c1 is the equivalent damping coefficient of the separation support device; Wherein F is the pressure received by the rubber; Wherein m is the system mass, δ l is the amplitude attenuation rate of the separation support device; Wherein, and are the initial and the n-th cycle amplitudes of the separation support device, respectively.

5. The method of claim 4, wherein, The method for calculating the vertical position and attitude information of the topside at the current time in Step 2 comprises: where F u (t) is the external load on the upper block at the current time, is the position attitude angle of the upper block at the current time, is the velocity angle of the upper block at the current time, is the velocity of the upper block at the current time, M u (t) is the time-varying mass matrix of the upper block at the current time, C u is the damping matrix of the upper block, K u is the stiffness matrix of the upper block; where is the position information of the upper block at the current time, is the attitude information of the upper block at the current time.

6. The method of claim 5, wherein, The method for calculating the vertical position and attitude information of the dynamically positioned ship at the current time in Step 2 comprises: where F s (t) is the external load on the dynamically positioned ship at the current time, is the position and attitude angle of the dynamically positioned ship at the current time, is the velocity angle of the dynamically positioned ship at the current time, is the velocity of the dynamically positioned ship at the current time, M s (t) is the time-varying mass matrix of the dynamically positioned ship at the current time; where ε is the external ballast water load; where is the position information of the dynamically positioned ship at the current time, is the attitude information of the dynamically positioned ship at the current time.

7. A computer device comprising a memory, a processor, and a computer program stored on the memory, wherein: The processor executes the computer program to implement the steps of the method in any one of claims 1 to 6.

8. A computer readable storage medium having stored thereon a computer program, characterized in that: The computer program / instruction is executed by the processor to implement the steps of the method in any one of claims 1 to 6.

9. A computer program product comprising a computer program, characterized in that: The computer program is executed by the processor to implement the steps of the method in any one of claims 1 to 6.

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