Near-Optimal Control for Offshore Structures with Nonlinear Energy Sink Mechanisms

Chen, Wei; Du, Xuehui; Zhang, Bao-Lin; Cai, Zhihui; Zheng, Zhongqiang

doi:10.3390/jmse10060817

Cited by 3 publications

(7 citation statements)

References 36 publications

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“…In other words, the NES-based dynamic model (2) presented in this paper is a more general one than the one in ref. [26]. In Equation (2), the coupled nonlinear terms of unmodelled vibration modes, system uncertainty, self-excited hydrodynamic force, and the wave force are considered, while in ref.…”

Section: Problem Formulationmentioning

confidence: 99%

“…In Equation (2), the coupled nonlinear terms of unmodelled vibration modes, system uncertainty, self-excited hydrodynamic force, and the wave force are considered, while in ref. [26], only the first dominant vibration mode of the structure with an NES is taken into account.…”

Section: Problem Formulationmentioning

confidence: 99%

“…Most recently, in ref. [26], an NES‐based near optimal control scheme is developed to control wave‐induced vibration of the offshore structure. Simulation results indicate that based on a properly designed NES device, the NES‐based near optimal controller is more effective than the TMD‐based one to suppress the vibration of the structure.…”

Section: Introductionmentioning

confidence: 99%

“…However, in ref. [26], the optimal controller design is based on an idealized model, where only the first vibration mode is considered, while other vibration modes are ignored, and the coupled nonlinear characteristics of unmodelled dynamics and system uncertainties are not taken into account. In fact, if the aforementioned factors are considered, the optimal control schemes are not applicable for the offshore structure.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Observer‐based sliding mode H∞$H_\infty$ control for offshore structures with nonlinear energy sink mechanisms

Chen

Zhang

et al. 2023

IET Control Theory & Appl

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It is significant to reduce the wave‐induced vibration and ensure the safety of the offshore structure. This paper deals with the observer‐based sliding mode vibration control problem of offshore structures with nonlinear energy sink (NES) mechanisms. By considering the coupled nonlinear characteristics of unmodelled dynamics, system uncertainty, and external wave force, a more general nonlinear system model of the offshore structure equipped with an NES mechanism is presented. Then, an observer‐based sliding mode control scheme for the nonlinear structure‐NES system is developed. The existence condition and the design algorithm of the observer‐based sliding mode controller are provided. Simulation results show that the observer‐based sliding mode controller is capable of reducing the wave‐induced vibration amplitude of offshore structures effectively. Compared with the NES‐based passive control, the observer‐based sliding mode controller can further reduce the response amplitudes of the offshore structure remarkably. In addition, the designed observer‐based sliding mode controller is robust the variations of structure parameters and the external wave loads, thereby presenting potential advantages of the active damping control of the offshore structure.

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Section: Problem Formulationmentioning

confidence: 99%

Section: Problem Formulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Observer‐based sliding mode H∞$H_\infty$ control for offshore structures with nonlinear energy sink mechanisms

Chen

Zhang

et al. 2023

IET Control Theory & Appl

Self Cite

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“…Piles are widely used in marine engineering, for the establishment of structures such as offshore wind turbines, offshore drilling platforms, and bridges. Piles are always exposed to a variety of external dynamic loads, such as wind, waves, and earthquakes [1,2]. Piles usually work in the form of closely spaced pile groups that bear the load transmitted by their caps.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Response of a Four-Pile Group Foundation in Liquefiable Soil Considering Nonlinear Soil-Pile Interaction

Bao

Liu

et al. 2022

JMSE

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Piles, which are always exposed to dynamic loads, are widely used in offshore structures. The dynamic response of the pile-soil-superstructure system in liquefiable soils is complicated, and the interaction between the pile and soil and the pile volume effect are the key influencing factors. In this study, a water-soil fully coupled dynamic finite element-finite difference (FE-FD) method was used to numerically simulate the centrifuge shaking table (CST) test of a four-pile group in saturated sand soil. An interface contact model was proposed to simulate the pile-soil interaction, and a solid element was used to consider the volume effect of the pile. The acceleration responses of the soil and pile, settlement deformation, excess pore water pressure, and bending moment were examined. The results show that the bending moment response of the two piles parallel to the shaking direction show minor differences, while the two piles perpendicular to the shaking direction show almost the same distribution. The values of excess pore water pressure at the same depth but different azimuth angles around the pile are also different. The numerical simulation can accurately reproduce soil deformation and pile internal force during and after dynamic loading.

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Model Reference Adaptive Vibration Control of an Offshore Platform Considering Marine Environment Approximation

Zhang

et al. 2023

JMSE

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Adaptive control methods are suitable for offshore steel structures subject to harmful vibrations, as they employ reference models to adapt to coastal and nearshore physics. To decrease the dependence on the accurate characteristics of the offshore platform, a compensating measure containing the ocean environment is proposed in the adaptive control scheme. With incomplete states as the driving input, external loads are approximated using a wavelet neural network frame. Numerical experiments are conducted on a platform model with varying parameters to test the performance of the proposed adaptive controller. It is shown that the adaptive weights derived from the chosen Lyapunov function are qualified both theoretically and practically. The system-output-based adaptive controller overcomes the disadvantage of state loss. The compensated disturbance environment guarantees the reliability of the restored reference system based on mismatched physics. The designed estimator as a part of the adaptive controller compensates for the deviations of the environment between the reference and the practical, resulting in a desirable reduction in the excessive vibration.

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Near-Optimal Control for Offshore Structures with Nonlinear Energy Sink Mechanisms

Cited by 3 publications

References 36 publications

Observer‐based sliding mode H∞$H_\infty$ control for offshore structures with nonlinear energy sink mechanisms

Observer‐based sliding mode H∞$H_\infty$ control for offshore structures with nonlinear energy sink mechanisms

Dynamic Response of a Four-Pile Group Foundation in Liquefiable Soil Considering Nonlinear Soil-Pile Interaction

Model Reference Adaptive Vibration Control of an Offshore Platform Considering Marine Environment Approximation

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