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Controlled Flight of a Biologically Inspired, Insect-Scale Robot
Flies are among the most agile flying creatures on Earth. To mimic this aerial prowess in a similarly sized robot requires tiny, high-efficiency mechanical components that pose miniaturization challenges governed by force-scaling laws, suggesting unconventional solutions for propulsion, actuation, and manufacturing. To this end, we developed high-power-density piezoelectric flight muscles and a manufacturing methodology capable of rapidly prototyping articulated, flexure-based sub-millimeter mechanisms. We built an 80-milligram, insect-scale, flapping-wing robot modeled loosely on the morphology of flies. Using a modular approach to flight control that relies on limited information about the robot's dynamics, we demonstrated tethered but unconstrained stable hovering and basic controlled flight maneuvers. The result validates a sufficient suite of innovations for achieving artificial, insect-like flight.
Journal Article
Plane queer
In this vibrant new history, Phil Tiemeyer details the history of men working as flight attendants. Beginning with the founding of the profession in the late 1920s and continuing into the post-September 11 era, Plane Queer examines the history of men who joined workplaces customarily identified as female-oriented. It examines the various hardships these men faced at work, paying particular attention to the conflation of gender-based, sexuality-based, and AIDS-based discrimination. Tiemeyer also examines how this heavily gay-identified group of workers created an important place for gay men to come out, garner acceptance from their fellow workers, fight homophobia and AIDS phobia, and advocate for LGBT civil rights. All the while, male flight attendants facilitated key breakthroughs in gender-based civil rights law, including an important expansion of the ways that Title VII of the 1964 Civil Rights Act would protect workers from sex discrimination. Throughout their history, men working as flight attendants helped evolve an industry often identified with American adventuring, technological innovation, and economic power into a queer space.
eBook
Insect flight
Throughout the 1950s, methods of experimental analysis led to a great increase in knowledge of the machinery of insect flight. This book brings together the results of Dr Pringle's investigations of the mechanics of wing motion, the structure and physiology of flight muscle, aerodynamics, sense organs and nervous co-ordination.
Book
New flight trajectory optimisation method using genetic algorithms
This paper presents a new flight trajectory optimisation method, based on genetic algorithms, where the selected optimisation criterion is the minimisation of the total cost. The candidate flight trajectories evaluated in the optimisation process are defined as flight plans with two components: a lateral flight plan (the set of geographic points that define the flight trajectory track segments) and a vertical flight plan (the set of data that define the altitude and speed profiles, as well as the points where the altitude and/or speed changes occur). The lateral components of the candidate flight plans are constructed by selecting a set of adjacent nodes from a routing grid. The routing grid nodes are generated based on the orthodromic route between the flight trajectory’s initial and final points, a selected maximum lateral deviation from the orthodromic route and a selected grid node step size along and across the orthodromic route. Two strategies are investigated to handle invalid flight plans (relative to the aircraft’s flight envelope) and to compute their flight performance parameters. A first strategy is to assign a large penalty total cost to invalid flight profiles. The second strategy is to adjust the invalid flight plan parameters (altitude and/or speed) to the nearest limit of the flight envelope, with priority being given to maintaining the planned altitude. The tests performed in this study show that the second strategy is computationally expensive (requiring more than twice the execution time relative to the first strategy) and yields less optimal solutions. The performance of the optimal profiles identified by the proposed optimisation method, using the two strategies regarding invalid flight profile performance evaluation, were compared with the performance data of a reference flight profile, using identical input data: initial aircraft weight, initial and final aircraft geographic positions, altitudes and speed, cost index, and atmospheric data. The initial and final aircraft geographic positions, and the reference flight profile data, were retrieved from the FlightAware web site. This data corresponds to a real flight performed with the aircraft model used in this study. Tests were performed for six Cost Index values. Given the randomness of the genetic algorithms, the convergence to a global optimal solution is not guaranteed (the solution may be non-optimal or a local optima). For a better evaluation of the performance of the proposed method, ten test runs were performed for each Cost Index value. The total cost reduction for the optimal flight plans obtained using the proposed method, relative to the reference flight plan, was between 0.822% and 3.042% for the cases when the invalid flight profiles were corrected, and between 1.598% and 3.97% for the cases where the invalid profiles were assigned a penalty total cost.
Journal Article
Can it fly?
Using simple text and pictures, this book presents examples of animals that can fly and animals that can't.
Book
Controlled flight of a microrobot powered by soft artificial muscles
Flying insects capable of navigating in highly cluttered natural environments can withstand in-flight collisions because of the combination of their low inertia
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and the resilience of their wings
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, exoskeletons
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and muscles. Current insect-scale (less than ten centimetres long and weighing less than five grams) aerial robots
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–
6
use rigid microscale actuators, which are typically fragile under external impact. Biomimetic artificial muscles
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–
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that are capable of large deformation offer a promising alternative for actuation because they can endure the stresses caused by such impacts. However, existing soft actuators
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–
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have not yet demonstrated sufficient power density to achieve lift-off, and their actuation nonlinearity and limited bandwidth create further challenges for achieving closed-loop (driven by an input control signal that is adjusted based on sensory feedback) flight control. Here we develop heavier-than-air aerial robots powered by soft artificial muscles that demonstrate open-loop (driven by a predetermined signal without feedback), passively stable (upright during flight) ascending flight as well as closed-loop, hovering flight. The robots are driven by multi-layered dielectric elastomer actuators that weigh 100 milligrams each and have a resonance frequency of 500 hertz and power density of 600 watts per kilogram. To increase the mechanical power output of the actuator and to demonstrate flight control, we present ways to overcome challenges unique to soft actuators, such as nonlinear transduction and dynamic buckling. These robots can sense and withstand collisions with surrounding obstacles and can recover from in-flight collisions by exploiting material robustness and vehicle passive stability. We also fly two micro-aerial vehicles simultaneously in a cluttered environment. They collide with the wall and each other without suffering damage. These robots rely on offboard amplifiers and an external motion-capture system to provide power to the dielectric elastomer actuators and to control their flight. Our work demonstrates how soft actuators can achieve sufficient power density and bandwidth to enable controlled flight, illustrating the potential of developing next-generation agile soft robots.
Heavier-than-air insect-scale aerial robots powered by soft artificial muscles can hover and also recover from in-flight collisions, illustrating the potential for developing next-generation agile soft robots.
Journal Article
Flying lizards big as planes
Imagine a giant flying creature as big as a plane. It's time to meet the enormous flying reptiles that swooped through the skies during the time of the dinosaurs. Each title in this new series digs deep into one fascinating area of the Dinosphere.
Book
Improving Power Generation in Rigid‐Wing Groundgen Airborne Wind Energy Systems Using Feedback Control—A Parametric Study
This paper explores different reel‐out strategies in a simulated environment to improve the power generation capability of Kitemill's KM1 prototype. The KM1 is a rigid‐wing groundgen airborne wind energy system that flies in circular loops during its power production phase. Firstly, we investigate the impact of flight and ground winch control. A major improvement of 47% more power over an existing reel‐out method can be achieved by combining winch control to maintain a constant reel‐out speed, along with using flight control to track a constant angle of attack and zero sideslip. Subsequently, a series of parameter sweeps were conducted to determine the best reel‐out trajectories. The parameter space considered includes wind speed, circle radius and reel‐out speed. Whilst there are many parameter combinations that provide similar power outputs, their effects on other operation metrics are different. For instance, excessively large circles cause a small drop in power generated (relative to the optimal value) and impose significant penalties on structural load, power quality (how much it fluctuates), airspace and ground space usage and flight control. Regarding the reel‐out speed, faster reel‐out provides more power and alleviates structural load at the cost of lower airspeed relative to the wind, which increases the risk of stalling the airframe. The proposed reel‐out strategies are compared with a published optimisation‐based study, which uncovered the importance of pitch control in power production. All analyses were conducted on a high‐fidelity simulator with tether dynamics. The simulator's accuracy was verified against past flight test data.
Journal Article