ROV attitude stability control method combined with hydrodynamic influence

Abstract

The invention discloses an ROV attitude stability control method combined with influence of hydrodynamic force, and relates to the technical field of attitude control of an unmanned remote control submersible, the control method comprises the following steps: firstly, establishing mutually independent three-dimensional ROV attitude dynamic models combined with hydrodynamic force, ship motion and umbilical cable vortex-induced vibration; secondly, adopting backstepping control and sliding mode control design, and adding an event triggering mechanism to optimize control output; and then a Volterra adaptive multi-step chaotic prediction algorithm is adopted to obtain a change track of a ship heave time sequence in advance, and condition parameters are provided for an event triggering mechanism in an active heave compensation system controller. According to the ROV attitude stability control method combined with the influence of the hydrodynamic force, the control task can be effectively completed, and the anti-interference capability is very high.

Description

Technical Field

[0001] The invention relates to the technical field of attitude control of unmanned remote-controlled submersibles, and in particular to an ROV attitude stabilization control method combined with the influence of hydrodynamics. Background Art

[0002] Unmanned remotely operated vehicles (ROVs) are important equipment for unmanned diving. ROVs have been increasingly widely used in the world because of their outstanding features such as safety, economy, high efficiency and large operating depth. Affected by wind and waves, the ROV's carrying platform inevitably produces multi-degree-of-freedom motion, which has a negative impact on the normal operation of the ROV. The ROV weakens this effect by controlling the spatial coordinates of the motion posture. The axial stability of the ROV is usually achieved by an active heave compensation system (AHC). The heave compensation system weakens the motion coupling between the ROV and the mother ship and the operating platform, reduces the internal stress changes of the umbilical cable, and thus stabilizes the tension of the umbilical cable on the ROV, ensuring the mechanical balance of the ROV in the axial direction. As for the horizontal posture stability of the ROV, a horizontal propulsion system is usually used to achieve it. By controlling the speed of the propulsion motor, different horizontal propulsion forces are given to the ROV, so that the ROV can be moved to any position on the plane.

[0003] The attitude stabilization system of ROV is usually composed of multiple drive devices. In order to save the channel resources of the umbilical cable, the event trigger mechanism is used to reduce the overhead of each subsystem, reduce the waste of channel resources, and improve the utilization rate of network resources. With the advent of the era of electric-driven underwater robots, many scholars at home and abroad have studied the ROV distributed system using the event trigger mechanism. It is desirable and necessary to add the event trigger mechanism to the ROV attitude control for output optimization. Summary of the invention

[0004] In view of the above technical problems to be solved, the present invention provides a ROV attitude stabilization control method combined with the influence of hydrodynamic force, which can effectively complete the control task and also has strong anti-interference ability.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: A method for ROV attitude stabilization control combined with the influence of hydrodynamic force, specifically comprising the following steps: Step S1, generating a ship heave motion time series according to the 6-DOF motion of the ship as input to the Volterra adaptive multi-step chaos prediction algorithm and ROV interference; Step S2, analyzing the vortex-induced vibration response of the umbilical cable based on the Euler-Bernoulli beam equation, and then calculating the total deformation variable caused by the vibration caused by the eddy current to obtain the dynamic effect of the vortex-induced vibration on the load; Step S3, building an ROV attitude dynamics model: using rigid body dynamics to model the ROV attitude, combining the ship-umbilical cable-ROV multi-body system and the vortex-induced vibration response of the umbilical cable and the hydrodynamic force of the ROV underwater to build a three-dimensional ROV attitude dynamics model; Step S4, predicting the heave motion of the ship based on the Volterra adaptive multi-step prediction algorithm according to the ROV attitude dynamics model, and then using the ROV space coordinate stability control method based on the event trigger mechanism, using backstepping control and sliding mode control, and adding the event trigger mechanism to optimize the control output of the ROV motion; obtaining the ROV motion attitude stability output.

[0006] As a further improvement of the above technical solution: Preferably, in step S1, the 6-DOF kinematic equation of the ship is: ; in, and are the mass matrix and the additional mass matrix respectively; is the displacement of the ship's motion; is the speed of the ship, is the acceleration of the ship, is the damping matrix; for hydrostatic recovery matrix; is the restoring force matrix of the mooring system; The force provided by the wind; is the wave force acting on the ship.

[0007] Preferably, the dynamic influence of the vortex-induced vibration on the load in step S2 is specifically: According to the variational principle, the Euler-Bernoulli beam equation of the umbilical cable is: ; in, Bending stiffness of the umbilical cable, is the stress at the umbilical-ship connection, is the additional mass coefficient, is the mass per unit area of ​​the umbilical cable, is the damping coefficient, The hydrodynamic force on the cable. is the longitudinal velocity of the umbilical cable, is the axial displacement of the umbilical cable, is the time variable; The calculation formula for the interference of vortex-induced vibration on ROV is: ; in, is the vortex-induced vibration response displacement of the umbilical cable, is the amplitude of the umbilical cable, is the length of the umbilical cable.

[0008] Preferably, in step S3, the ROV attitude dynamics model is three-directional, and the longitudinal dynamics equation is: ; The lateral dynamic equation is: ; The axial dynamic equation is: ; in, is the load mass, is the longitudinal coordinate of the load center of gravity, is the longitudinal displacement of the ROV, is the longitudinal speed of ROV, is the lateral displacement of the ROV, is the lateral speed of the ROV, is the angle of rotation around the axis, Angular acceleration about the axis, is the area mapped from the load side to the plane, is the longitudinal displacement of ROV, is the seawater resistance coefficient, is the load lift coefficient, and It is the controlling force of the load in the longitudinal and lateral directions; is the load lateral vibration mode, and For additional interference, is the axial acceleration, is the radius of the load, is the Young's modulus of the umbilical cable, is the length of the umbilical cable, is the crane height for heave compensation control, is the displacement of the ship, is the vortex-induced vibration response displacement of the umbilical cable, is the axial displacement, is the water resistance coefficient of the load.

[0009] Preferably, in step S4, firstly, the time lag of the heave compensation system in the heave direction among the three directions is predicted to obtain the advance predicted amount of the ship's heave motion, and the heave compensation system compensates the predicted amount to ensure the displacement synchronization of the ship and the load; then, an event trigger mechanism is designed to define the event to be triggered when the displacement deviates; the ROV attitude controller is designed according to the compensation error, and the controller uses a sliding mode control strategy, and an event trigger mechanism is introduced into the attitude displacement controller, which can be triggered according to the event trigger condition during the attitude adjustment process to update the control law of the controller, and the update of the event trigger condition of the control process is defined by the error variable, and the trigger condition is related to the predicted displacement of the ship, the heave compensation displacement and the vortex-induced vibration hydrodynamics of the ROV in the z direction.

[0010] Preferably, the predicted amount of the ship heave motion is calculated using a Volterra adaptive multi-step prediction algorithm, specifically: exist Get the advance prediction of the ship's heave and sink motion at all times , we get the heave compensation system equation after adding the prediction algorithm: ; in, is the state equation, is the correlation effect between subsystems, is an unknown parameter, is the disturbance term, is the control input, and is the state variable coefficient, , ; Volterra adaptive multi-step chaos prediction algorithm For time The actual tracking trajectory error of the heave compensation system is defined as , whose derivative is:

[0011] in, is the correlation effect between subsystems, is an unknown parameter, is the disturbance term, For control input.

[0012] The ROV attitude stabilization control method combined with the influence of hydrodynamic force provided by the present invention has the following advantages compared with the prior art: (1) The present invention relates to a ROV attitude stabilization control method under the influence of hydrodynamic forces. First, the motion of the ship under different sea conditions is simulated by using the rigid body motion law and adding sea breeze and wave models, providing input for the Volterra adaptive multi-step chaos prediction algorithm and the axial interference of the ROV. The Volterra adaptive multi-step chaos prediction algorithm has obvious advantages over the traditional maximum Lyapunov chaos prediction algorithm in terms of training time and accuracy. In addition, the ROV three-dimensional state equation is constructed in combination with the hydrodynamic forces of the ROV.

[0013] (2) The present invention combines the ROV attitude stabilization control method affected by hydrodynamics. The event trigger mechanism optimizes the output of the control law without reducing the performance of the basic control strategy, improves the control output broadband utilization, and effectively saves broadband resources. The update time of the controlled system control law is determined by the event trigger condition. The update cycle is large during the time period when the change rate of the control law is large. The event trigger time interval of the control law update of the heave compensation system is consistent with the heave displacement change trend. The heave attitude is only adjusted under the event trigger mechanism, which effectively saves resources. All event trigger time intervals are strictly greater than 0, and there is no Zeno behavior. Due to the constraint of the error in the event trigger condition, the event trigger mechanism designed by the present invention improves the anti-interference ability of the controlled system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a flow chart of ROV attitude stabilization control event triggering in the present invention.

[0015] Figure 2 It is a mapping diagram of the ROV space coordinates on the xy plane in the experimental verification of the present invention.

[0016] Figure 3 It is a diagram of the AHC heave compensation effect in the experimental verification of the present invention.

[0017] Figure 4 It is the X-axis event triggering time period.

[0018] Figure 5 It is the Y-axis event triggering time period.

[0019] Figure 6 It is the event triggering time period in the heave direction. DETAILED DESCRIPTION

[0020] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0021] The ROV attitude stabilization control method combined with the influence of hydrodynamics of the present invention first establishes the ROV attitude stabilization dynamics model, and solves the ROV dynamics equation by converting the physical coordinates into the modal space to decouple the ROV attitude stabilization system to obtain the three-dimensional dynamic state equation of ROV attitude control, and the state equation combines the influence of ROV fluid dynamics, ship motion and umbilical cable vortex-induced vibration. The ROV attitude stabilization control method adopts backstepping control and sliding mode control design, and on this basis, an event trigger mechanism (Event Trigger Mechanism, ETM) is added to optimize its control output, and an adaptive multi-step chaos prediction algorithm (Volterra) obtains the change trajectory of the ship heave time series in advance, and provides conditional parameters for the event trigger mechanism in the active heave compensation (ActiveHeave Compensation, AHC) controller to improve the positioning accuracy in the heave direction.

[0022] The ROV attitude stabilization control method includes heave, longitudinal and lateral control. The heave compensation control consists of an outer loop and an inner loop. The outer loop controls the heave displacement, and the inner loop controls the angle of the driving winch. Here is the controller for the outer loop to control the heave displacement.

[0023] The ROV attitude stabilization control method combined with the hydrodynamic influence of the present invention comprises the following steps: Step S1, generating a time series of ship heave motion to provide input for the Volterra adaptive multi-step chaos prediction algorithm and the axial disturbance of the ROV.

[0024] In complex sea conditions, the ship will produce 6 degrees of freedom motion. These motion disturbances are transmitted to the ROV through the umbilical cable, which greatly interferes with the spatial coordinate stability of the ROV. According to Newton's second law, the 6-degree-of-freedom kinematic equation of the ship is: (1) in, and are the mass matrix and the additional mass matrix respectively; is the displacement of the ship's motion; is the speed of the ship, is the acceleration of the ship, is the damping matrix; for hydrostatic recovery matrix; is the restoring force matrix of the umbilical cable; for wind power; The wave forces acting on the ship are calculated using the Kaimal turbulent wind spectrum and the Jonswap wave spectrum, respectively.

[0025] According to formula (1), the amplitude of the ship's heave motion time series increases with the increase of sea state level, and the amplitude of the wind speed and wave height increases, which is consistent with the characteristics of the actual situation; the amplitude of the ship's heave motion time series increases with the increase of sea state level, and after being relatively stable, the range of change of the 4th level sea state is , the change range is up to , and the rise and fall amplitude in level 6 sea conditions reaches .

[0026] Step S2, analyzing the vortex-induced vibration response of the umbilical cable based on the Euler-Bernoulli beam equation.

[0027] The umbilical cable is a slender and flexible marine engineering equipment. During operation, the umbilical cable will generate vortex-induced vibration due to the action of the ocean current, which will cause the deformation of the umbilical cable. Especially when the vibration frequency is close to the natural frequency of the umbilical cable, resonance will occur. The stress change caused by this deformation will be transmitted to the load along the umbilical cable, affecting the movement of the load, so it is necessary to analyze the interference in detail.

[0028] According to the variational principle, the Euler-Bernoulli beam equation of the umbilical cable can be expressed as: (2) in, Bending stiffness of the umbilical cable, is the stress at the umbilical-ship connection, is the additional mass coefficient, is the mass per unit area of ​​the umbilical cable, is the damping coefficient, The hydrodynamic force on the cable. is the longitudinal velocity of the umbilical cable, is the axial displacement of the umbilical cable, is a time variable. ,in is the density of seawater, is the umbilical cable diameter, is the reference lift system observed on the fixed structure under the action of vortex shedding. The Euler-Bernoulli beam equation of the umbilical cable is a 4th-order partial differential equation, and four boundary conditions are required to obtain the solution. According to the design goal of the ROV attitude motion control of the present invention, the part of the umbilical cable connected to the ship moves with the ship, and the displacement of the part connected to the ROV end is 0, and its boundary conditions can be set as: (3) in, is the amplitude of the umbilical cable, is the displacement of the ship, is the acceleration of the ship, is the length of the umbilical cable.

[0029] The influence of vortex-induced vibration on the dynamic load is reflected in the influence of cable stress, and the source of stress change is deformation. Therefore, by calculating the total deformation variable caused by the vibration caused by eddy current, the dynamic influence of vortex-induced vibration on the load can be obtained. The interference calculation of vortex-induced vibration on ROV is shown in formula (4): (4) in, is the vortex-induced vibration response displacement of the umbilical cable.

[0030] Step S3, building an ROV attitude dynamics model.

[0031] The rigid body dynamics theory is used to model the ROV motion attitude control system.

[0032] To model the ROV motion posture, we first make an assumption, that is, the ideal state: a. The main body of the ROV is a cylindrical rigid body; b. The umbilical cable is always in tension; c. The ROV has a uniform mass density.

[0033] The longitudinal and lateral dynamic equations of the ROV are: (5) (6) in, is the load mass, is the longitudinal coordinate of the load center of gravity, is the longitudinal displacement of the ROV, is the longitudinal speed of ROV, is the lateral displacement of the ROV, is the lateral speed of the ROV, is the angle of rotation around the axis, Angular acceleration about the axis, is the area mapped from the load side to the plane, is the longitudinal displacement of ROV, is the seawater resistance coefficient, is the load lift coefficient, and It is the controlling force of the load in the longitudinal and lateral directions; is the load lateral vibration mode, and For additional interference.

[0034] The axial stability of the ROV is mainly guaranteed by the active heave compensation system (AHC). Therefore, combining the ship-umbilical cable-ROV multi-body system and the hydrodynamic force of the ROV underwater, the axial dynamic equation is: (7) in, is the axial acceleration, is the radius of the load, is the Young's modulus of the umbilical cable, is the length of the umbilical cable, is the crane height for heave compensation control, is the displacement of the ship, is the vortex-induced vibration response displacement of the umbilical cable, is the axial displacement, is the water resistance coefficient of the load.

[0035] Step S4, ROV attitude control method based on event triggering mechanism.

[0036] First, the time lag of the heave compensation system in the heave direction of the three directions is predicted to obtain the advance prediction of the ship's heave motion. The heave compensation system compensates the prediction to ensure the displacement synchronization between the ship and the load. Then, the event trigger mechanism is designed to define the event to be triggered when the displacement deviates; the ROV attitude controller is designed according to the compensation error. The controller uses a sliding mode control strategy and introduces an event trigger mechanism in the attitude displacement controller. This mechanism can be triggered according to the event trigger condition during the attitude adjustment process, and then the control law of the controller is updated. The update of the event trigger condition of the entire control process is defined by the error variable. Therefore, the trigger condition is related to the predicted displacement of the ship, the heave compensation displacement and the vortex-induced vibration hydrodynamics of the ROV in the z direction. In order to ensure the effectiveness of the controller design, the stability of the control system is proved, and the boundedness of the event trigger condition is proved.

[0037] S4-1, calculate the predicted amount of the ship's heave motion, and compensate the predicted amount through the heave compensation system.

[0038] The heave compensation system for ROV axial stability control is a large time-delay system, which is responsive to the displacement of the ship's motion. There is a phase difference. , the degrees of freedom are decoupled from each other, and combined with the heave compensation system, it is: (8) in, is the intermediate variable, ; It is the time from when the MRU (ship attitude sensor) collects the ship status to when the heave compensation system makes a control response, that is, the lag time.

[0039] In order to solve the time lag problem of the heave compensation system, a prediction algorithm is introduced. The time series of the ship's heave motion has chaotic characteristics, so a chaotic prediction algorithm can be used to predict the ship's heave motion. The addition of the prediction algorithm can effectively weaken the compensation error caused by the time lag of the heave compensation system. The present invention adopts a Volterra-based adaptive multi-step prediction algorithm. The Volterra series can be used to expand the nonlinear system. Assuming the chaotic time series of the ship's motion, the input of its nonlinear discrete dynamic system is , the output is: .

[0040] The Volterra adaptive multi-step chaos prediction algorithm is used to Get the advance prediction of the ship's heave and sink motion at all times , substituting it into equation (8), we can obtain the heave compensation system equation after adding the prediction algorithm: (9) The formula (9) can be simplified as: (10) in, is the state equation, is the correlation effect between subsystems, is an unknown parameter, is the disturbance term, is the control input, and is the state variable coefficient, , , which is the controller.

[0041] At the same time, according to the requirement that the heave compensation system accurately compensates the heave motion of the ship under the action of hydrodynamics, it can be seen that when the displacement compensated by the heave compensation system has the same amplitude and phase as the heave displacement of the ship, the coupling relationship between the ship and the ROV will be released. Therefore, the Volterra adaptive multi-step chaos prediction algorithm obtains For time The actual tracking trajectory error of the heave compensation system is defined as , whose derivative is: (11) in, is the correlation effect between subsystems, is the state variable, is an unknown parameter, is the disturbance term, is the control input, .

[0042] S4-2, design the event trigger mechanism and define the event to be triggered when the displacement deviates.

[0043] S4-2-1, design the event trigger mechanism, controller and position parameter observer. Combined with the initial state, the designed parameters should satisfy :

[0044] (12) in, for Transformed tracking performance function; It is bounded; , It is a parameter that needs to be designed, and its main function is to limit the range of state error.

[0045] The controller designed by formula (10) introduces an event trigger mechanism. Assume that the controller is When the ROV attitude stabilization control method is able to calculate a new control law through the algorithm, the control law is controlled by the zero-order holder. The control law remains stable during the time interval.

[0046] S4-2-2, design event trigger conditions, event trigger conditions are defined as: (13) in, is the actual tracking performance error, is the intermediate variable, , is the actual tracking trajectory error of the heave compensation system, Volterra adaptive multi-step chaos prediction algorithm Get the advance prediction of the ship's heave and sink motion at all times. and is a normal number. When the event triggering condition is met, , as well as Reset to zero. For the next event triggering moment, you can get.

[0047] S4-2-3, design the ROV heave compensation system controller.

[0048] The heave compensation system is a time-delay system with complex interference. Therefore, the selection of control strategy usually requires a control strategy with small computational complexity and strong robustness to improve anti-interference ability and real-time control ability. Therefore, the sliding mode control strategy is selected for the heave compensation system control. According to the heave compensation system equation, it is: (14) in, In order to introduce the control equation of the heave compensation system with sliding mode control strategy, , is the tracking error in the z direction, is the expected target of heave displacement, is the heave displacement, , To control the parameters, is the differential term of the tracking error, , for The activation function can make the control input more continuous and smooth by adjusting the function parameters.

[0049] The backstepping method is used to design the unknown parameter observer and controller of the ROV motion posture in the x and y axes. As follows: (15) in, is the x-axis error vector, is the y-axis error vector. Finally, an event trigger mechanism is added based on equation (15). ,z dimension, is the expected target value on the x-axis, is the expected target value on the y-axis, and the solution of the state target is 0, so ; For the axial dimension , , is the heave displacement of the ship. , substituting it into equation (13), we can get the event triggering conditions for ROV motion posture control in the x, y, and z axes: (16) is the tracking error in the x direction, is the tracking error in the y direction, is the tracking performance error in the x direction, is the tracking performance error in the y direction. So far, the design of the ROV attitude stabilization controller is completed. Figure 1 This is the event triggering flow structure diagram of ROV attitude stabilization control.

[0050] Experimental verification A simulation model is built in MATLAB / Simulink. The main parameters of the simulation model are shown in Table 1.

[0051] Table 1 Simulation parameters:

[0052] This experiment mainly verifies the changes in spatial coordinates and event triggering mechanism of ROV attitude stability control. Figure 2 is the projection of the ROV spatial coordinates on the xy plane, where the red dot is the initial coordinate of the ROV on the xy plane, and the blue dot is the target coordinate; the blue solid line is the ROV adjustment trajectory without the event trigger mechanism, and the red dotted line is the ROV adjustment trajectory with the event trigger mechanism. It can be seen from the figure that the event trigger mechanism has no significant effect on the ROV trajectory, and the deviation between the two trajectories is not obvious, indicating that the addition of the event trigger mechanism will not affect the ROV attitude control process.

[0053] Figure 3 The axial coordinates of the ROV are adjusted for the heave compensation system. The blue curve is the actual compensation displacement required by the ROV, the orange-red dotted line is the displacement compensated by the ROV after the event trigger mechanism is added, and the orange is the compensation error between the two. The error range is between ±0.1m, which has little effect on the compensation process.

[0054] from Figure 4 It can be seen that during the ROV attitude control state adjustment in the x direction, the time interval of event triggering is between 0.001s and 0.15s from 0 to 2s, and the time interval of event triggering is between 0.01s and 0.02s from 57s to 57.2s. Figure 5 It can be seen that in the y direction, during the ROV attitude control state adjustment period, the event triggering time interval is between 0.005s and 0.055s from 0 to 2s, and the event triggering time interval is between 0.003s and 0.004s from 60s to 60.2s. The control law updates in both directions are more frequent than during the state stability period, and the triggering time interval fluctuates more. The reason is that the change rate of the control law during the event triggering period is large, and the update cycle (event triggering time interval) is larger. Figure 6 The event triggering time interval for updating the control law of the medium heave compensation system is consistent with the changing trend of the heave displacement, and the heave attitude is only adjusted under the event triggering mechanism, which effectively saves resources.

[0055] The step size of the simulation setting in this experimental verification is , and from Figures 4 to 6 It can be seen that the control period of the attitude motion in the three dimensions of x, y, and z is less than the simulation step length, which means that the event trigger mechanism effectively reduces the invalid output of the control signal and optimizes the output of the control law. The event trigger time interval for updating the control law of the heave compensation system is consistent with the change trend of the heave displacement. The heave attitude is only adjusted under the event trigger mechanism, which effectively saves resources.

[0056] The above implementation cases are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, they are not intended to limit the present invention. Therefore, any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for ROV attitude stabilization control combined with hydrodynamic influence, characterized in that: The specific steps include: Step S1, generating a ship heave motion time series according to the 6-DOF motion of the ship as input to the Volterra adaptive multi-step chaos prediction algorithm and ROV interference; Step S2, analyzing the vortex-induced vibration response of the umbilical cable based on the Euler-Bernoulli beam equation, and then calculating the total deformation variable caused by the vibration caused by the eddy current to obtain the dynamic effect of the vortex-induced vibration on the load; Step S3, building an ROV attitude dynamics model, using rigid body dynamics to model the ROV attitude, and combining the ship-umbilical cable-ROV multi-body system and the vortex-induced vibration response of the umbilical cable and the hydrodynamic force of the ROV underwater to build a three-dimensional ROV attitude dynamics model; Step S4, predicting the heave motion of the ship based on the Volterra adaptive multi-step prediction algorithm according to the ROV attitude dynamics model, and then designing the ROV spatial coordinate stability control based on the event trigger mechanism, using backstepping control and sliding mode control, and adding the event trigger mechanism to optimize the control output of the ROV motion; obtaining the ROV motion attitude stability output.

2. The ROV attitude stabilization control method combined with the influence of hydrodynamic force according to claim 1 is characterized in that: In step S1, the 6-DOF kinematic equation of the ship is: ； in, and are the mass matrix and the additional mass matrix respectively; is the displacement of the ship's motion; is the speed of the ship, is the acceleration of the ship, is the damping matrix; To restore the matrix for still water; is the restoring force matrix of the umbilical cable; for wind power; is the wave force acting on the ship.

3. The ROV attitude stabilization control method combined with the influence of hydrodynamic force according to claim 2 is characterized in that: The dynamic effect of vortex-induced vibration on load in step S2 is specifically: According to the variational principle, the Euler-Bernoulli beam equation of the umbilical cable is: ； in, Bending stiffness of the umbilical cable, is the stress at the umbilical-ship connection, is the additional mass coefficient, is the mass per unit area of ​​the umbilical cable, is the damping coefficient, The hydrodynamic force on the cable. is the longitudinal velocity of the umbilical cable, is the axial displacement of the umbilical cable, is the time variable; The calculation formula for the interference of vortex-induced vibration on ROV is: ； in, is the vortex-induced vibration response displacement of the umbilical cable, is the amplitude of the umbilical cable, is the length of the umbilical cable.

4. The ROV attitude stabilization control method combined with the influence of hydrodynamic force according to claim 3 is characterized in that: In step S3, the ROV attitude dynamics model is three-directional, and the longitudinal dynamics equation is: ； The lateral dynamic equation is: ； The axial dynamic equation is: ； in, is the load mass, is the longitudinal coordinate of the load's center of gravity, is the longitudinal speed of ROV, is the lateral displacement of the ROV, is the lateral speed of the ROV, is the angle of rotation around the axis, Angular acceleration about the axis, is the area mapped from the load side to the plane, is the longitudinal displacement of ROV, is the seawater resistance coefficient, is the load lift coefficient, and It is the controlling force of the load in the longitudinal and lateral directions; is the load lateral vibration mode, and For additional interference, is the axial acceleration, is the radius of the load, is the Young's modulus of the umbilical cable, is the length of the umbilical cable, is the crane height for heave compensation control, is the displacement of the ship, is the vortex-induced vibration response displacement of the umbilical cable, is the axial displacement, is the water resistance coefficient of the load.

5. The ROV attitude stabilization control method combined with the influence of hydrodynamic force according to claim 4 is characterized in that: In the step S4, firstly, the time lag of the heave compensation system in the heave direction among the three directions is predicted to obtain the advance predicted amount of the ship's heave motion, and the heave compensation system compensates the predicted amount to ensure the displacement synchronization of the ship and the load; then, an event trigger mechanism is designed to define the event to be triggered when the displacement deviates; the ROV attitude controller is designed according to the compensation error, and the controller uses a sliding mode control strategy, and an event trigger mechanism is introduced into the attitude displacement controller, which can be triggered according to the event trigger condition during the attitude adjustment process to update the control law of the controller, and the update of the event trigger condition of the control process is defined by the error variable, and the trigger condition is related to the predicted displacement of the ship, the heave compensation displacement and the vortex-induced vibration hydrodynamics of the ROV in the z direction.

6. The ROV attitude stabilization control method combined with the influence of hydrodynamic force according to claim 5 is characterized in that: The predicted amount of the ship heave motion is calculated using the Volterra adaptive multi-step prediction algorithm, specifically: exist Get the advance prediction of the ship's heave and sink motion at all times , we get the heave compensation system equation after adding the prediction algorithm: ； in, is the state equation, is the correlation effect between subsystems, is an unknown parameter, is the disturbance term, is the control input, and is the state variable coefficient, , ; Volterra adaptive multi-step chaos prediction algorithm For time The solution, is the axial acceleration, and the actual tracking trajectory error of the heave compensation system is defined as , whose derivative is: ； in, is the correlation effect between subsystems, is an unknown parameter, is the disturbance term, For control input.

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