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Marine flexible riser boundary vibration control method for model uncertainty

A flexible standpipe and control equation technology, applied in the direction of adaptive control, general control system, control/adjustment system, etc., can solve the problem of low control accuracy, achieve higher calculation speed, reduce calculation amount, and better tracking and adjustment Effect of Vibration Conditions

Active Publication Date: 2022-05-06
SOUTHWEST PETROLEUM UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The invention provides a method for controlling the boundary vibration of an ocean flexible riser with an uncertain model, so as to solve the defect of low control accuracy caused by the control method in the prior art relying on the precise mathematical model of the ocean flexible riser, and to realize that it does not rely on an accurate model , can well compensate the uncertainty of the flexible riser system and the uncertainty of the external load, and at the same time can effectively track and adjust the vibration condition and actively suppress the vibration of the riser

Method used

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  • Marine flexible riser boundary vibration control method for model uncertainty
  • Marine flexible riser boundary vibration control method for model uncertainty
  • Marine flexible riser boundary vibration control method for model uncertainty

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0079] Boundary vibration control methods for marine flexible risers for model uncertainties, such as figure 2 shown, including the following steps:

[0080]Model the flexible riser, obtain the control equation of the flexible riser system, and determine the boundary conditions and initial conditions of the flexible riser system;

[0081] Based on the adaptive fuzzy inversion algorithm, the adaptive fuzzy inversion control law of the flexible riser system is established; and then through the Lyapunov stability theory, it is verified whether the system is stable and bounded: if it is, go to the next step; if not, readjust the first step A control parameter and / or a second control parameter and / or a third control parameter.

[0082] Obtain the actual offset of the lateral vibration of the flexible riser;

[0083] Substituting the actual offset into the adaptive fuzzy inversion control law to obtain an actual control output;

[0084] Based on the actual control output, the fl...

Embodiment 2

[0086] The schematic diagram of the marine flexible riser system model in this embodiment is as follows figure 1 as shown, figure 1 The dotted arrow in the middle indicates the distributed ocean current, the origin of the coordinate system is at the bottom of the riser, and the controller is at the top (boundary) of the riser for control input to generate lateral force to suppress the vibration of the riser, and the control direction is to the right. Where: the riser length is L , the lateral vibration offset of the riser is w ( x , t ), the distributed ocean current load acting on the riser is f ( x , t ), the boundary disturbance is d ( t ), the space variable is x ; the time variable is t , which in this embodiment represents an operation interval period.

[0087] The control process of the present embodiment is as follows:

[0088] 1. Modeling, dynamic analysis of the flexible riser system model:

[0089] Will figure 1 The kinetic energy of the flexible ri...

Embodiment 3

[0132] On the basis of Example 2, this example conducts experimental verification for the boundary vibration control method of the marine flexible riser with uncertain models:

[0133] System parameter selection: lambda 2 =7.37×10 8 , r 2 =1, k 2 =1, initial value θ 2 (0) is 0. fuzzy membership function mu Fi j ( x i ) adopts Z-shaped membership functions at both ends of the domain of discourse, and adopts triangular membership functions in the middle area. The two input quantities of the two-dimensional fuzzy controller are respectively set to 7 language value levels, so 49 control rules can be obtained. The remaining main parameters of the flexible riser system are shown in Table 1:

[0134] Table 1 Other main parameters of the flexible riser system

[0135]

[0136] Distributed current loads acting on the riser f ( x , t ) is expressed by the following formula:

[0137]

[0138] In the formula, ρ s is the seawater density, C D is the drag co...

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Abstract

The invention discloses a marine flexible riser boundary vibration control method for model uncertainty, which comprises the following steps of: modeling a flexible riser to obtain a control equation of a flexible riser system, and determining a boundary condition and an initial condition of the flexible riser system; based on an adaptive fuzzy inversion algorithm, establishing an adaptive fuzzy inversion control law of the flexible riser system; the actual transverse vibration offset of the flexible vertical pipe is obtained; substituting the actual offset into the adaptive fuzzy inversion control law to obtain actual control output; and controlling the flexible riser at the top end based on the actual control output. The method is used for overcoming the defect that in the prior art, the control precision is low due to the fact that a control method depends on an accurate mathematical model of the marine flexible riser, and the uncertainty of a flexible riser system and the uncertainty of an external load can be well compensated without depending on the accurate model; and meanwhile, the vibration condition can be effectively tracked and adjusted, and the aim of actively restraining vibration of the vertical pipe is achieved.

Description

technical field [0001] The invention relates to the field of offshore oil and gas exploitation, in particular to a method for controlling the boundary vibration of an ocean flexible riser with uncertain models. Background technique [0002] With the gradual strengthening of the exploration of offshore oil and gas resources and the continuous deepening of drilling depth, more and more technical problems need to be solved in the development of offshore oil and gas. For floating platforms / ships or semi-submersible platforms / ships, flexible risers are an important channel connecting subsea oil wells and surface platforms, and are also a weak link in offshore oil transportation. Due to its special marine working environment, the vibration phenomenon of the flexible riser is unavoidable, and the vibration will make the riser fatigue, shorten its working life, increase its production cost and may bring fatal safety production risks. [0003] For offshore oil and gas production, th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G05B13/02
CPCG05B13/024Y02T90/00
Inventor 万敏周莉王国荣王川许海英赵娜张强唐斌
Owner SOUTHWEST PETROLEUM UNIV
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