Observer-Based Unknown Input Estimator of Wave Excitation Force for a Wave Energy Converter

Abdelrahman, Mustafa; Patton, Ron J.

doi:10.1109/tcst.2019.2944329

Cited by 12 publications

(7 citation statements)

References 29 publications

(61 reference statements)

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“…It is found by comparing the peak and trough calculation formulas obtained by fitting, and, combined with the experimental research results, the difference of the maximum wave force between pile groups at the peak and trough is about 1.1 times. erefore, in order to facilitate the application of the formula, the two fitting calculation formulas are combined to obtain (6), which is the final calculation formula of wave force on pile groups.…”

Section: Calculation Methods Of Wave Force Of Pile Groupmentioning

confidence: 99%

“…erefore, in order to ensure the safety of large-scale seacrossing bridge structures, it is necessary to calculate the load on the large-scale structure accurately to preserve the marine life safely [5]. However, there is no clear formula and method for wave load calculation of large-scale structure in the current design code for sea-crossing bridge pier column foundation structure, the large-scale structure of seacrossing bridge is subjected to extreme waves and natural disasters [6,7]. e research on the impact of the combined load of water flow has become a concern for many species and sea life [8].…”

Section: Introductionmentioning

confidence: 99%

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Experimental Study on Wave Force on Large-Scale Pier Column Foundation of Sea-Crossing Bridge for Preserving the Marine Environment

Liu

et al. 2022

Mathematical Problems in Engineering

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Based on the project sea area where the large-scale sea-crossing bridge is located, the marine environment is facing the threat of severe marine environmental issues such as strong typhoons and big waves. In order to resist the impact of the super wave load, the research focuses on a new structure derived from soft computing techniques in a simulated environment. Since the conventional methods cannot be used for handling such an important problem, soft computing techniques can certainly help to provide simulated solutions. These solutions can be exploited in a real-time environment to test their viability. The overall physical model test of the wave with a scale of 1 : 40 is carried out in this research study by using the proposed methodology. By setting a series of groups such as different wave height, period, water level (pier foundation scouring depth), and wave-current coupling, it is studied that the wave height and period are in positive proportion to the wave force on the pier column structure. However, there is no obvious relationship with the water level change (scouring depth). The buoyancy of the pile cap structure is about 1.27 times greater than that of the pier structure. Compared with the combined wave force of the single wave and wave current, the sensitivity and the relationship have been studied. Using this study and several engineering results completed in the early stage and also verified by the measured data, the results show that the proposed soft computing technique has good accuracy and can provide a reference for the load estimation of large-scale foundation structures.

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Section: Calculation Methods Of Wave Force Of Pile Groupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental Study on Wave Force on Large-Scale Pier Column Foundation of Sea-Crossing Bridge for Preserving the Marine Environment

Liu

et al. 2022

Mathematical Problems in Engineering

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“…Therefore, to achieve the best control performance by non-causal LOC which requires 5 × T p wave excitation force prediction, it is essential to design a SM compensator to compensate for both estimation and prediction errors. The control performance with and without SM compensation is compared in the case of H s = 0.04 m and T p = 1.8 s. Since the proposed "ASMO + improved AR" strategy enables us to explicitly calculate the estimation boundary and the prediction boundary, the gain parameter of SMC can be determined by (20). The energy output and power generated are shown in Fig.…”

Section: Cwrmentioning

confidence: 99%

“…13, in which the minimal error bound is found to be 1.0668 with k 2 = 9.9 and µ 2 = 3.5. Hence, as calculated by (20), the minimal compensation gain is 1.038. The comparison among control performance with different tuning of parameters is shown in Fig.…”

Section: Simulation Set 4: Design Of Prediction Horizon N P and Comentioning

confidence: 99%

“…To achieve non-causal control using the statistical methods with satisfactory performance relies on a combination of a wave force estimation technique with sufficient accuracy and the following prediction method based on a segment of latest historical data produced by the wave estimation. To estimate the excitation force in realtime, extended Kalman filter (EKF) [13], [19], unknown input observer [20] and adaptive sliding mode observer (ASMO) [21] have been proposed to cope with uncertainties with acceptable estimation error. Based on the historical estimations, AR and EKF have been applied to predict incoming excitation forces [13]- [16].The proposed NLOC+ASMO has its roots in the recent techniques developed in [5], [18], [21].…”

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confidence: 99%

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Non-causal Linear Optimal Control With Adaptive Sliding Mode Observer for Multi-Body Wave Energy Converters

Zhang

Stansby

2021

IEEE Trans. Sustain. Energy

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Development of model-based and model-free reactive control scheme: considering copper loss and movable-floater-displacement constraint for a wave energy converter

2023

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The utilization of wave energy is expected since ocean wave energy has a high potential. The improvement of the feasibility of wave energy converters requires control that maximizes the electric output energy, including the copper loss under a displacement constraint. Several model-based and model-free reactive controls have been developed. Although model-based reactive control attains high performance, it struggles to deal with modeling errors and forecasting wave excitation forces. On the other hand, the model-free reactive control can adapt to dynamic modeling, including modeling errors; however, it requires a vast amount of learning data and considerable time and effort to consider the displacement constraint. Model-based and model-free reactive controls each have advantages and disadvantages. Combined model-based and model-free reactive controls are desirable to freely switch between the model-based and model-free reactive controls based on various ocean situations. In this study, two equivalent model-based and model-free reactive controls that can consider the copper loss and displacement constraints without forecasting the wave excitation forces were proposed. The model-free reactive control was compared with the model-based reactive control and a conventional control using numerical simulations in irregular waves. The results of the simulation show that the proposed model-based reactive control achieves superior performance compared to that of the conventional control. The proposed model-free reactive control achieved comparable performance to that of the proposed model-based reactive control under various wave conditions. Moreover, the proposed model-free reactive control decreased the required training trials. The development of the two equivalent control schemes will lead to the proposal of combined model-based and model-free reactive controls in the future.

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Observer-Based Unknown Input Estimator of Wave Excitation Force for a Wave Energy Converter

Cited by 12 publications

References 29 publications

Experimental Study on Wave Force on Large-Scale Pier Column Foundation of Sea-Crossing Bridge for Preserving the Marine Environment

Experimental Study on Wave Force on Large-Scale Pier Column Foundation of Sea-Crossing Bridge for Preserving the Marine Environment

Non-causal Linear Optimal Control With Adaptive Sliding Mode Observer for Multi-Body Wave Energy Converters

Development of model-based and model-free reactive control scheme: considering copper loss and movable-floater-displacement constraint for a wave energy converter

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