NRI: Development of Autonomous Sub-Gram Flapping-Wing Artificial Flyers Using Novel Combustion-Driven SMA-Based Actuators

这个项目解决了动力和控制问题，这是实现可操作、自主、不受束缚、昆虫级飞行机器人的核心问题。即使是最好的小电池，每单位质量所储存的能量也很低，以至于飞行时间最多只能限制在几分钟内。此外，当考虑到电池必须提供能量的高速率时，一个有翅膀的微型机器人是否能举起自己的重量是值得怀疑的。相反，这个项目模仿自然界中的飞虫，它们使用动物脂肪作为燃料，其能量密度比最先进的电池高100倍左右。因此，该项目将展示液体燃料催化燃烧发动机，预计能够进行超过90分钟的动力飞行。这一结果将通过昆虫尺度空气动力学、燃烧和飞行的创新集成建模、分析、设计、制造和控制来实现。昆虫级飞行机器人的应用将产生更广泛的影响，例如，人工授粉、搜救行动和野外生物研究。间接地，该项目将产生新的能量转换方法，新的控制合成算法和制造技术，适用于广泛的轮式，有翼和有腿的微型机器人。为了实现项目目标，研究在三个特定领域推进知识：(i)生物启发设计和制造空气动力学高效的扑翼微型飞行器，将自然原理转化为机器人设计，采用系统和控制概念框架。在这个框架中，空气动力学、动力、设计和控制之间的相互作用是使用输入输出建模和系统识别等工具进行分析的；（ii）使用燃料驱动的基于形状记忆合金的机械驱动机制，其中无焰催化燃烧产生诱导材料相变所需的热量，这是产生机械功所必需的；（iii）控制，这是从前两个领域自然产生的，因为新的空气动力学高效设计需要发明新的稳定飞行控制策略和控制器合成的新技术。同样，新的驱动技术需要发明新的低层次的、物理上可实现的控制器。在这种情况下，燃烧驱动致动器和扑动机构的动力学是非线性和时变的，因此研究工作的重要部分是致力于开发和实时实现新的鲁棒稳定非线性和自适应控制器。

This project addresses power and control questions central to achieving maneuverable, autonomous, untethered, insect-scale, flying robots. The amount of energy stored per unit mass in even the best small batteries is low enough that flight times would be limited to at most a few minutes. Furthermore, when the high rate at which the battery must supply energy is considered, it is questionable whether a winged microrobot could even lift its own weight. Instead, this project emulates flying insects in nature, which use animal fat as fuel, with an energy density about 100 times greater than state-of-the-art batteries. Accordingly, this project will demonstrate liquid-fuel catalytic combustion engines expected to be capable of over 90 minutes of powered flight. This result will be achieved through innovative integrated modeling, analysis, design, fabrication, and control of insect-scale aerodynamics, combustion, and flight. Broader impacts will arise from application of insect-scale flying robots to, for example, artificial pollination, search-and-rescue operations, and field biological research. Indirectly, this project will produce new methods for energy conversion, novel algorithms for control synthesis, and fabrication techniques, applicable to a wide gamut of wheeled, winged, and legged microrobots.To accomplish the project goals, the research advances knowledge in three specific areas: (i) biologically inspired design and fabrication of aerodynamically efficient flapping-wing microflyers, where principles from nature are translated into robotic designs, employing a systems-and-control conceptual framework. In this framework, the interaction between aerodynamics, power, design, and controls is analyzed using tools such as input-output modeling and system identification; (ii) mechanical actuation using fuel-powered shape-memory-alloys-based mechanisms, where flameless catalytic combustion generates the heat required to induce material phase transitions, necessary for the production of mechanical work; (iii) control, which emerges naturally from the first two areas as new aerodynamically efficient designs require the invention of novel control strategies for stable flight and new techniques for controller synthesis. Similarly, new actuation technologies require the invention of new low-level, physically implementable controllers. In this case, the dynamics of the combustion-driven actuators and flapping mechanisms are nonlinear and time-varying, reason for which a significant part of the research effort is dedicated to the development and real-time implementation of novel robustly stable nonlinear and adaptive controllers.