Collaborative Research: Unsteady Hydrodynamics and Geometric Control of Pisciform Locomotion

这一合作项目将通过研究鱼形运动-即通过研究鱼类动物使用的运动策略-改进用于流体中推进和控制的物理模型和控制设计方法的最新水平。该项目平衡了基本分析、数值模拟和物理实验。这项工作的一个基石是开发一个模块化的生物运动仿真器（MBE），它可以被配置为展示不同的鱼形策略的全方位，从振荡运动（例如金枪鱼使用的）到波动运动（例如鳗鱼使用的）。这些结果将推进工程系统的能力，朝着速度，敏捷，隐身，鲁棒性和效率的惊人能力，在鱼类动物中看到的。以前的鱼类运动模型在很大程度上依赖于准稳态流动假设，无法捕捉身体和流体之间重要的非稳态相互作用。这项工作将制定，确定和验证一个低维，状态空间模型的非定常流的影响，并将该模型纳入一个几何控制框架，使最佳形态和步态的设计。具体而言，该研究计划将产生（i）非定常涡格法（UVLM）作为模拟鱼形运动的工具的评估，（ii）一个实验验证的，降阶状态空间表示的非定常力的一系列移动翼在流中，（iii）使用已被修正以包括不稳定流效应的几何控制模型来优化鱼形游泳者的形态和步态的方法，以及（iv）来自使用MBE的拖曳实验的运动、力和可视化数据的参数储存库。

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.