Feedforward and feedback optimal control for offshore structures subjected to irregular wave forces

Ma, Hui; Tang, Gong‐You; Zhao, Yandong

doi:10.1016/j.oceaneng.2005.07.009

Cited by 92 publications

(63 citation statements)

References 8 publications

(8 reference statements)

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“…Because the pair (A, B) is controllable, it can be claimed that P 1 is the unique positive-semi-definite solution of (28). Noting (11) and the first formula (26), we have that all of the eigenvalues of (A T P 1 S −1 BR −1 B T ) satisfy λ i (A T P 1 S −1 BR −1 B T ) < 1.…”

Section: Theoremmentioning

confidence: 96%

“…The simple structure of jacket-type offshore platform with an active mass damper (AMD) device is shown in Figure 1 [28]. The global dynamic equation of a jacket-type offshore platform is given by the following coupled equations:…”

Section: Jacket-type Offshore Platformmentioning

confidence: 99%

“…Taking the jacket-type offshore platform located in Bohai Bay into consideration, the parameters of installed AMD and offshore structure are listed in Table 1 [28].…”

Section: Parameters Of Wave Disturbance Attenuation Problemmentioning

confidence: 99%

“…In this subsection, in order to illustrate the effectiveness of proposed digital-control-based AOWDAC, the following optimal feedback and feedfoward vibration controller (OFFVC) designed in [28] is used for comparison purposes, which is described as…”

Section: Analysis Of Wave Disturbance Attenuation Abilities Of Proposmentioning

confidence: 99%

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Digital-Control-Based Approximation of Optimal Wave Disturbances Attenuation for Nonlinear Offshore Platforms

et al. 2017

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Abstract:The irregular wave disturbance attenuation problem for jacket-type offshore platforms involving the nonlinear characteristics is studied. The main contribution is that a digital-control-based approximation of optimal wave disturbances attenuation controller (AOWDAC) is proposed based on iteration control theory, which consists of a feedback item of offshore state, a feedforward item of wave force and a nonlinear compensated component with iterative sequences. More specifically, by discussing the discrete model of nonlinear offshore platform subject to wave forces generated from the Joint North Sea Wave Project (JONSWAP) wave spectrum and linearized wave theory, the original wave disturbances attenuation problem is formulated as the nonlinear two-point-boundary-value (TPBV) problem. By introducing two vector sequences of system states and nonlinear compensated item, the solution of introduced nonlinear TPBV problem is obtained. Then, a numerical algorithm is designed to realize the feasibility of AOWDAC based on the deviation of performance index between the adjacent iteration processes. Finally, applied the proposed AOWDAC to a jacket-type offshore platform in Bohai Bay, the vibration amplitudes of the displacement and the velocity, and the required energy consumption can be reduced significantly.

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Section: Theoremmentioning

confidence: 96%

Section: Jacket-type Offshore Platformmentioning

confidence: 99%

“…Taking the jacket-type offshore platform located in Bohai Bay into consideration, the parameters of installed AMD and offshore structure are listed in Table 1 [28].…”

Section: Parameters Of Wave Disturbance Attenuation Problemmentioning

confidence: 99%

Section: Analysis Of Wave Disturbance Attenuation Abilities Of Proposmentioning

confidence: 99%

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Digital-Control-Based Approximation of Optimal Wave Disturbances Attenuation for Nonlinear Offshore Platforms

et al. 2017

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“…Individual pitch control has been investigated by a number of researchers and shown to be beneficial [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. However, individual pitch control can reduce only the oscillation of blade bending moment, not its steady-state value.…”

Section: Introductionmentioning

confidence: 99%

Two LQRI based Blade Pitch Controls for Wind Turbines

Park

Nam

2012

Energies

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Abstract:As the wind turbine size has been increasing and their mechanical components are built lighter, the reduction of the structural loads becomes a very important task of wind turbine control in addition to maximum wind power capture. In this paper, we present a separate set of collective and individual pitch control algorithms. Both pitch control algorithms use the LQR control technique with integral action (LQRI), and utilize Kalman filters to estimate system states and wind speed. Compared to previous works in this area, our pitch control algorithms can control rotor speed and blade bending moments at the same time to improve the trade-off between rotor speed regulation and load reduction, while both collective and individual pitch controls can be designed separately. Simulation results show that the proposed collective and individual pitch controllers achieve very good rotor speed regulation and significant reduction of blade bending moments.

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Optimal disturbance rejection control for singularly perturbed composite systems with time‐delay

Zhang

Tang

Yue

2009

Asian Journal of Control

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The optimal control problem for a class of singularly perturbed time‐delay composite systems affected by external disturbances is investigated. The system is decomposed into a fast linear subsystem and a slow time‐delay subsystem with disturbances. For the slow subsystem, the feedforward compensation technique is proposed to reject the disturbances, and the successive approximation approach (SAA) is applied to decompose it into decoupled subsystems and solve the two‐point boundary value (TPBV) problem. By combining with the optimal control law of the fast subsystem, the feedforward and feedback composite control (FFCC) law of the original composite system is obtained. The FFCC law consists of analytic state feedback and feedforward terms and a compensation term which is the limit of the adjoint vector sequence. The compensation term can be obtained from an iteration formula of adjoint vectors. Simulation results are employed to test the validity of the proposed design algorithm. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society

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Feedforward and feedback optimal control for offshore structures subjected to irregular wave forces

Cited by 92 publications

References 8 publications

Digital-Control-Based Approximation of Optimal Wave Disturbances Attenuation for Nonlinear Offshore Platforms

Digital-Control-Based Approximation of Optimal Wave Disturbances Attenuation for Nonlinear Offshore Platforms

Two LQRI based Blade Pitch Controls for Wind Turbines

Optimal disturbance rejection control for singularly perturbed composite systems with time‐delay

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