Collaborative Research: Lift regulation via kinematic maneuvering in uncertain gusts

当机翼穿过强风时，很快就会产生大量的升力。由此产生的瞬态升力及其形成的速度对车辆的控制提出了挑战，并可能导致结构变形或失效。因此，为机翼配备减轻强阵风反应（即调节升力）的方法是很有意义的。该项目的长期目标是评估电梯生产对阵风流不确定性的敏感性，并创建新的控制策略，以减轻在有害的不可预见的阵风遭遇时的电梯瞬变。这项工作的结果将适用于广泛的应用，包括在潮汐、波浪和尾迹中运行的风力和水力涡轮机；以及各种规模的空中和水上交通工具，从在城市环境中运行的小型飞行器到在复杂地形、空气尾流和极端天气中运行的载人飞行器。该项目还将包括教育和推广活动，包括小学和中学的访问，以及对本科转校生的研究和指导计划。本项目的目标是应用流体动力学、降阶建模和最优鲁棒控制理论的工具来阐明和建模非定常和不确定的大振幅横向强风遭遇的潜在流动物理，并应用这些知识来设计控制规律，通过运动驱动来调节该事件期间和之后的升力生产。技术方法是：(1)综合基于高分辨率非定常力、流场和表面压力测量的刚性机翼在大振幅横向阵风遭遇中的前缘和尾缘涡动力学的物理低阶模型；(2)构建一个最优鲁棒控制框架，用于阵风升力调节，适当考虑阵风流的不确定性（如宽度和振幅）和机翼对其的响应；(3)在实验室实时阵风遭遇实验中实现所提出的闭环控制框架。研究活动将探索将分析和基于物理的空气动力学模型与数据驱动技术相结合的方法，以获得通过非定常和不确定大扰动的更健壮和可扩展的机翼模型。对科学界的贡献包括(1)为具有高度不确定性的大振幅阵风设计的流动模型，以及(2)将该模型集成到一个鲁棒实时反馈控制回路中，用于在没有阵风参数先验知识的情况下进行翼阵风相遇的运动学机动。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

When a wing passes through a strong gust of wind, large amounts of lift are generated very quickly. The resulting lift transient, and the speed at which it builds, presents a challenge to maintaining vehicle control and can result in structural deformation or failure. It is therefore of interest to equip wings with ways to mitigate strong gust responses, i.e., to regulate lift. The long-term goal of this project is to assess the sensitivity of lift production to uncertainties in the gust flow, and to create new control strategies for mitigation of lift transients during detrimental unforeseen gust encounters. Results of this work will apply to a broad range of applications including wind and water turbines operating in tides, waves, and wakes; and air and water vehicles of all scales, from small aerial vehicles operating in urban environments to manned vehicles operating in complex terrain, air wakes, and extreme weather. The project will also encompass educational and outreach activities, including elementary and middle school visits and a research and mentoring program for undergraduate transfer students.The goal of this project is to apply tools from fluid dynamics, reduced-order modeling, and optimal and robust control theory to elucidate and model the underlying flow physics of an unsteady and uncertain large-amplitude transverse gust encounter, and to apply this knowledge to design control laws for regulation of lift production through kinematic actuation during and after this event. The technical approach is to (1) synthesize a physics-based low-order model that includes leading- and trailing-edge vortex dynamics based on high-resolution unsteady force, flow field, and surface pressure measurements on a rigid wing in a large-amplitude transverse gust encounter; (2) construct an optimal robust control framework for lift regulation in the gust that properly accounts for uncertainties in the gust flow (e.g., width and amplitude) and the wing's response thereto; and (3) implement the proposed closed-loop control framework in real-time gust encounter experiments in the laboratory. Research activities will explore methods of combining analytical and physics-based aerodynamic models with data-driven techniques for more robust and extensible models of wings passing through unsteady and uncertain large disturbances. Contributions to the scientific community include (1) a flow model designed for large-amplitude gust encounters with a high degree of uncertainty in the gust flow, and (2) integration of this model into a robust real-time feedback control loop for kinematic maneuvering in a wing-gust encounter without a priori knowledge of the gust parameters.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.