Boundary Vibration Control Method for Marine Flexible Riser Aiming at Model Uncertainty

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

Active Publication Date: 2022-06-07
SOUTHWEST PETROLEUM UNIV
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  • Summary
  • 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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  • Boundary Vibration Control Method for Marine Flexible Riser Aiming at Model Uncertainty
  • Boundary Vibration Control Method for Marine Flexible Riser Aiming at Model Uncertainty
  • Boundary Vibration Control Method for Marine Flexible Riser Aiming at Model Uncertainty

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Experimental program
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Effect test

Embodiment 1

[0079] For the boundary vibration control method of marine flexible riser with uncertain model, such as figure 2 shown, including the following steps:

[0080]Model the flexible riser, obtain the governing equations 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; then through the Lyapunov stability theory, it is verified whether the system is stable and bounded: if yes, 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] Substitute the actual offset into the adaptive fuzzy inversion control law to obtain an actual control output;

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

Embodiment 2

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

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

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

[0089] Will figure 1 Kinetic energy of flexible riser system shown...

Embodiment 3

[0132] On the basis of Embodiment 2, this embodiment conducts experimental verification for the boundary vibration control method of the marine flexible riser whose model is uncertain:

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

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

[0135]

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

[0137]

[0138] In the formula, ρ s is the density of sea water, C D is the drag coefficient, D is the oute...

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Abstract

The invention discloses a method for controlling the boundary vibration of an ocean flexible riser with an uncertain model, modeling the flexible riser, obtaining the control equation of the flexible riser system, and determining the boundary conditions and initial conditions of the flexible riser system; based on the self-adaptive fuzzy The inversion algorithm is to establish the adaptive fuzzy inversion control law of the flexible riser system; obtain the actual offset of the lateral vibration of the flexible riser; substitute the actual offset into the adaptive fuzzy inversion control law to obtain the actual Control output; based on said actual control output, the flexible riser is controlled at the tip. The invention is used to solve the defect of low control precision caused by the control method in the prior art relying on the precise mathematical model of the marine flexible riser, realizes that it does not rely on the precise model, and can well compensate the uncertainty of the flexible riser system and the uncertainty of external loads, and at the same time, it can effectively track and adjust the vibration conditions and actively suppress the vibration of the riser.

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 an uncertain model. Background technique [0002] With the gradual strengthening of the exploration of offshore oil and gas resources and the deepening of the drilling depth, there are more and more technical problems 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 offshore 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 fatigue the riser, shorten its working life, increase its production cost and possibly bring fatal production safety risks. [0003] For offshore oil and gas exploitation,...

Claims

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Application Information

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Patent Type & Authority Patents(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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