论文标题
部分可观测时空混沌系统的无模型预测
A model predictive control (MPC)-integrated multiphase immersed boundary (IB) framework for simulating wave energy converters (WECs)
论文作者
论文摘要
在这项工作中，我们提出了一种新型的MPC集成的多相IB框架，该框架可以通过与高保真数值波罐（NWT）动态相互作用来计算最佳的能量最大化控制力。由于需要在IB模拟的每个时间步骤解决约束优化问题，因此MPC算法利用基于线性电位理论（LPT）的设备的低维动力学模型。另一方面，多相IB求解器基于高维虚拟域Brinkman惩罚（FD/BP）方法，该方法将与波浪结构相互作用（WSI）相关的流体动力非线性（WSI）完全分辨。实施了预测自动回归模型的时间序列，该模型预测波高的高度以估计MPC算法的未来波动激发/Froude-Krylov力。此外，我们还首次以MPC公式进行了非线性Froude-Krylov（NLFK）力。在不同的海洋条件下，将MPC集成多相IB求解器的预测与广泛流行的基于LPT的求解器进行了比较。总体而言，比较六个WSI/MPC求解器组合的垂直圆柱体。我们还确定了从波到功率起飞（PTO）系统的能量传递的途径，并使用IB模拟验证关系。此外，在IB模拟中模拟了三个不同的海态，以测试MPC对WEC的适应能力。事实证明，MPC适应了不断变化的海洋条件，并为每个海州找到最佳解决方案。
In this work, we present a novel MPC-integrated multiphase IB framework that can compute the optimal energy-maximizing control force on-the-fly by dynamically interacting with a high-fidelity numerical wave tank (NWT). Due to the requirement of solving a constrained optimization problem at each time step of the IB simulation, the MPC algorithm utilizes a low-dimensional dynamical model of the device that is based on the linear potential theory (LPT). The multiphase IB solver, on the other hand, is based on the high-dimensional fictitious domain Brinkman penalization (FD/BP) method, which fully-resolves the hydrodynamic nonlinearities associated with the wave-structure interaction (WSI). A time-series forecasting auto-regressive model is implemented that predicts wave heights to estimate the future wave excitation/Froude- Krylov forces for the MPC algorithm. Moreover, we also experiment with non-linear Froude-Krylov (NLFK) forces for the first time in an MPC formulation. Under varying sea conditions, the predictions of the MPC-integrated multiphase IB solver are compared to the widely popular LPT-based solvers. Overall, six WSI/MPC solver combinations are compared for a heaving vertical cylinder. We also determine the pathway of energy transfer from the waves to the power take-off (PTO) system and verify the relationships using IB simulations. Additionally, three different sea states are simulated within the IB simulation to test the adaptive capability of MPC for WECs. MPC is demonstrated to adapt to changing sea conditions and find the optimal solution for each sea state.
