Collaborative Research: Unsteady Hydrodynamics and Geometric Control of Pisciform Locomotion

这个合作项目将通过对鱼形运动的研究，即通过对类鱼动物的运动策略的研究，提高流体推进和控制的物理模型和控制设计方法的先进水平。该项目平衡了基础分析、数值模拟和物理实验。这项工作的基石是模块化生物运动模拟器（MBE）的开发，该模拟器可以配置为演示不同鱼类策略的全频谱，从振荡运动（例如金枪鱼）到波动运动（例如鳗鱼）。研究结果将提高工程系统的能力，使其在速度、敏捷性、隐身性、稳健性和效率方面达到惊人的水平。以前的鱼形运动模型在很大程度上依赖于准稳态流动假设，这些假设未能捕捉到身体和流体之间重要的非稳态相互作用。这项工作将制定、识别和验证非定常流动效应的低维状态空间模型，并将该模型纳入几何控制框架，从而实现最佳形态和步态的设计。具体而言，该研究项目将产生(i)评估非定常涡晶格方法（UVLM）作为模拟鱼形运动的工具，（ii）实验验证的，流中一系列运动箔上的非定常力的降阶状态空间表示，（iii）使用已修正的几何控制模型优化鱼形游泳者的形态和步态的方法，该模型已包括非定常流效应。（iv）使用MBE进行拖曳实验的运动、力和可视化数据的参数化存储库。

This collaborative project will improve the state-of-the-art of physical models and control design methods for propulsion and control in fluids, through the study of pisciform locomotion -- that is, through the study of movement strategies used by fishlike animals. The project balances fundamental analysis, numerical simulation, and physical experiments. A cornerstone of the effort is the development of a modular biolocomotion emulator (MBE) that can be configured to demonstrate the full spectrum of distinct pisciform strategies, from oscillatory locomotion (used, for example, by tuna) to undulatory locomotion (used, for example, by eels). The results will advance the capabilities of engineered systems, towards the astonishing capabilities for speed, agility, stealth, robustness, and efficiency seen in fishlike animals.Previous models of pisciform locomotion have largely relied on quasi-steady flow assumptions that fail to capture important unsteady interactions between the body and the fluid. This effort will formulate, identify and validate a low-dimensional, state space model for unsteady flow effects and incorporate that model into a geometric control framework that enables the design of optimum morphologies and gaits. Specifically, the research program will produce (i) an assessment of the unsteady vortex lattice method (UVLM) as a tool for modeling pisciform locomotion, (ii) an experimentally validated, reduced-order state space representation for the unsteady forces on a series of moving foils in a flow, (iii) methods for optimizing the morphology and gait of a pisciform swimmer using a geometric control model that has been amended to include unsteady flow effects, and (iv) a parametric repository of motion, force, and visualization data from towing experiments using the MBE.