scholarly journals Flight mechanics and control of escape manoeuvres in hummingbirds. II. Aerodynamic force production, flight control and performance limitations

2016 ◽  
Vol 219 (22) ◽  
pp. 3532-3543 ◽  
Author(s):  
Bo Cheng ◽  
Bret W. Tobalske ◽  
Donald R. Powers ◽  
Tyson L. Hedrick ◽  
Yi Wang ◽  
...  
Keyword(s):  
Flight Control ◽  
Aerodynamic Force ◽  
Force Production ◽  
Flight Mechanics ◽  
Performance Limitations ◽  
And Performance ◽  
And Control

scholarly journals THE LOCUST TEGULA: SIGNIFICANCE FOR FLIGHT RHYTHM GENERATION, WING MOVEMENT CONTROL AND AERODYNAMIC FORCE PRODUCTION

1993 ◽  
Vol 182 (1) ◽  
pp. 229-253 ◽  
Author(s):  
H Wolf
Keyword(s):  
Flight Control ◽  
Aerodynamic Force ◽  
Motor Pattern ◽  
Vertical Component ◽  
Sense Organ ◽  
Force Production ◽  
Movement Control ◽  
Rhythm Generation ◽  
Wing Movement ◽  
Before And After

The tegula, a complex sense organ associated with the wing base of the locust, plays an important role in the generation of the flight motor pattern. Here its function in the control of wing movement and aerodynamic force production is described.The vertical component of forewing movement was monitored while recording intracellularly from flight motoneurones during stationary flight. First, in accordance with previous electrophysiological results, stimulation of hindwing tegula afferents was found to reset the wingstroke to the elevation phase in a well-coordinated manner. Second, recordings made before and after removal of fore- and hindwing tegulae were compared. This comparison demonstrated that the delayed onset of elevator motoneurone activity caused by tegula removal is accompanied by a corresponding delay in the upstroke movement of the wings.The consequences of this delayed upstroke for aerodynamic force production were investigated by monitoring wing movements and lift generation simultaneously. A marked decrease in net lift generation was observed following tegula removal. Recordings of wing pronation indicate that this decrease in lift is primarily due to the delayed upstroke movement - that is, to a delay of the wings near the aerodynamically unfavourable downstroke position.It is concluded that the tegula of the locust hindwing signals to the nervous system the impending completion of the wing downstroke and allows initiation of the upstroke movement immediately after the wings have reached the lower reversal point of the wingstroke. The functional significance of tegula feedback and central rhythm generation for locust flight control are discussed.

scholarly journals Towards Bio-Inspiration, Development, and Manufacturing of a Flapping-Wing Micro Air Vehicle

Drones ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 39
Author(s):  
P. Lane ◽  
G. Throneberry ◽  
I. Fernandez ◽  
M. Hassanalian ◽  
R. Vasconcellos ◽  
...  
Keyword(s):  
Aerodynamic Force ◽  
Force Production ◽  
Flight Test ◽  
Flapping Wing ◽  
Micro Air Vehicle ◽  
Air Vehicle ◽  
Successful Design ◽  
The Stability ◽  
And Control ◽  
The Impact

Throughout the last decade, there has been an increased demand for intricate flapping-wing drones with different capabilities than larger drones. The design of flapping-wing drones is focused on endurance and stability, as these are two of the main challenges of these systems. Researchers have recently been turning towards bioinspiration as a way to enhance aerodynamic performance. In this work, the propulsion system of a flapping-wing micro air vehicle is investigated to identify the limitations and drawbacks of specific designs. Each system has a tandem wing configuration inspired by a dragonfly, with wing shapes inspired by a bumblebee. For the design of this flapping-wing, a sizing process is carried out. A number of actuation mechanisms are considered, and two different mechanisms are designed and integrated into a flapping-wing system and compared to one another. The second system is tested using a thrust stand to investigate the impact of wing configurations on aerodynamic force production and the trend of force production from varying flapping frequency. Results present the optimal wing configuration of those tested and that an angle of attack of two degrees yields the greatest force production. A tethered flight test is conducted to examine the stability and aerodynamic capabilities of the drone, and challenges of flapping-wing systems and solutions that can lead to successful flight are presented. Key challenges to the successful design of these systems are weight management, force production, and stability and control.

scholarly journals Speed Control and Force-Vectoring of Blue Bottle Flies in a Magnetically-Levitated Flight Mill

2018 ◽  
Author(s):  
Shih-Jung Hsu ◽  
Neel Thakur ◽  
Bo Cheng
Keyword(s):  
Flight Control ◽  
Insect Flight ◽  
Aerodynamic Force ◽  
Speed Control ◽  
The Body ◽  
Flight Mill ◽  
Wing Motion ◽  
Force Magnitude ◽  
Magnetically Levitated ◽  
And Control

Flies fly at a broad range of speeds and produce sophisticated aerial maneuvers with precisely controlled wing movements. Remarkably, only subtle changes in wing motion are used by flies to produce aerial maneuvers, resulting in little directional tilt of aerodynamic force vector relative to the body. Therefore, it is often considered that flies fly according to a helicopter model and control speed mainly via force-vectoring enabled primarily by body-pitch change. Here we examine the speed control of blue bottle flies using a magnetically-levitated (MAGLEV) flight mill, as they fly at different body pitch and with different augmented aerodynamic damping. We identify wing kinematic contributors to the changes of estimated aerodynamic force through testing two force-vectoring models. Results show that in addition to body pitch, flies also use a collection of wing kinematic variables to control both force magnitude and direction, the roles of which are analogous to those of throttle, collective and cyclic pitch of helicopters. Our results also suggest that the MAGLEV flight mill system can be potentially used to study the roles of visual and mechanosensory feedback in insect flight control.

Hummingbird hovering performance in hyperoxic heliox: effects of body mass and sex.

1996 ◽  
Vol 199 (12) ◽  
pp. 2745-2755 ◽  
Author(s):  
P Chai ◽  
R Harrykissoon ◽  
R Dudley
Keyword(s):  
Power Output ◽  
Aerodynamic Force ◽  
Force Production ◽  
Power Input ◽  
Flight Mechanics ◽  
Flight Performance ◽  
Metabolic Power ◽  
Significant Extent ◽  
Mechanical Power Output ◽  
Stroke Amplitude

Owing to their small size and hovering locomotion, hummingbirds are the most aerobically active vertebrate endotherms. Can hyperoxia enhance the flight performance of this highly oxygen-dependent group? Hovering performance of ruby-throated hummingbirds (Archilochus colubris) was manipulated non-invasively using hyperoxic but hypodense gas mixtures of sea-level air combined with heliox containing 35% O2. This manipulation sheds light on the interplay among metabolic power input, mechanical power output and aerodynamic force production in limiting flight performance. No significant differences in flight mechanics and oxygen consumption were identified between hyperoxic and normoxic conditions. Thus, at least in the present experimental context, hyperoxia did not change the major metabolic and mechanical parameters; O2 diffusive capacities of the respiratory system were probably not limiting to a significant extent. Compared with hummingbirds in our previous studies, the present experimental birds were heavier, had resultant shorter hover-feeding durations and experienced aerodynamic failure at higher air densities. Because hummingbirds have relatively stable wingbeat frequencies, modulation of power output was attained primarily through variation in stroke amplitude up to near 180 degrees. This result indicates that maximum hovering performance was constrained geometrically and that heavier birds with greater fat loads had less margin for enhancement of power production. Sexual dimorphism in flight adaptation also played a role, with males showing more limited hovering capacities, presumably as a trade-off for increased maneuverability.

scholarly journals Deformable wing kinematics in the desert locust: how and why do camber, twist and topography vary through the stroke?

2008 ◽  
Vol 6 (38) ◽  
pp. 735-747 ◽  
Author(s):  
Simon M. Walker ◽  
Adrian L. R. Thomas ◽  
Graham K. Taylor
Keyword(s):  
Flight Control ◽  
High Speed ◽  
Schistocerca Gregaria ◽  
Aerodynamic Force ◽  
Angle Of Attack ◽  
Force Production ◽  
Linear Increase ◽  
Trailing Edge ◽  
Wing Kinematics ◽  
Drag Ratio

Here, we present a detailed analysis of the wing kinematics and wing deformations of desert locusts ( Schistocerca gregaria , Forskål) flying tethered in a wind tunnel. We filmed them using four high-speed digital video cameras, and used photogrammetry to reconstruct the motion of more than 100 identified points. Whereas the hindwing motions were highly stereotyped, the forewing motions showed considerable variation, consistent with a role in flight control. Both wings were positively cambered on the downstroke. The hindwing was cambered through an ‘umbrella effect’ whereby the trailing edge tension compressed the radial veins during the downstroke. Hindwing camber was reversed on the upstroke as the wing fan corrugated, reducing the projected area by 30 per cent, and releasing the tension in the trailing edge. Both the wings were strongly twisted from the root to the tip. The linear decrease in incidence along the hindwing on the downstroke precisely counteracts the linear increase in the angle of attack that would otherwise occur in root flapping for an untwisted wing. The consequent near-constant angle of attack is reminiscent of the optimum for a propeller of constant aerofoil section, wherein a linear twist distribution allows each section to operate at the unique angle of attack maximizing the lift to drag ratio. This implies tuning of the structural, morphological and kinematic parameters of the hindwing for efficient aerodynamic force production.

scholarly journals Biomechanics and biomimetics in insect-inspired flight systems

2016 ◽  
Vol 371 (1704) ◽  
pp. 20150390 ◽  
Author(s):  
Hao Liu ◽  
Sridhar Ravi ◽  
Dmitry Kolomenskiy ◽  
Hiroto Tanaka
Keyword(s):  
Aerodynamic Force ◽  
Force Production ◽  
Micro Air Vehicles ◽  
Research Area ◽  
Integrated System ◽  
Flying Insects ◽  
Power And Control ◽  
Integrated Research ◽  
Control Flight ◽  
And Control

Insect- and bird-size drones—micro air vehicles (MAV) that can perform autonomous flight in natural and man-made environments are now an active and well-integrated research area. MAVs normally operate at a low speed in a Reynolds number regime of 10 4 –10 5 or lower, in which most flying animals of insects, birds and bats fly, and encounter unconventional challenges in generating sufficient aerodynamic forces to stay airborne and in controlling flight autonomy to achieve complex manoeuvres. Flying insects that power and control flight by flapping wings are capable of sophisticated aerodynamic force production and precise, agile manoeuvring, through an integrated system consisting of wings to generate aerodynamic force, muscles to move the wings and a control system to modulate power output from the muscles. In this article, we give a selective review on the state of the art of biomechanics in bioinspired flight systems in terms of flapping and flexible wing aerodynamics, flight dynamics and stability, passive and active mechanisms in stabilization and control, as well as flapping flight in unsteady environments. We further highlight recent advances in biomimetics of flapping-wing MAVs with a specific focus on insect-inspired wing design and fabrication, as well as sensing systems. This article is part of the themed issue ‘Moving in a moving medium: new perspectives on flight’.

Control and handling qualities considerations for an advanced supersonic transport aircraft

1999 ◽  
Vol 103 (1024) ◽  
pp. 265-272
Author(s):  
A. J. Steer ◽  
M. V. Cook
Keyword(s):  
Flight Control ◽  
Fully Integrated ◽  
Transport Aircraft ◽  
Handling Qualities ◽  
Supersonic Transport ◽  
Handling Characteristics ◽  
Research Activities ◽  
Propulsion Control ◽  
And Performance ◽  
And Control

Abstract A future advanced supersonic transport aircraft (AST) has fundamental characteristics and problems inherent to supersonic cruise aircraft with corresponding unique control and handling characteristics. In order to optimise the aerodynamic performance across the full flight envelope a fully integrated flight and propulsion control system will be required. However, this will need to be designed from the outset within clearly defined flight control and performance guidelines. Relevant existing and AST specific handling qualities criteria will need to be developed if a successful commercial transport aircraft is to be produced. This paper begins by presenting an overview of existing supersonic transport (SST) aircraft operations and current second generation SST research activities and design considerations. This is followed by an analysis of the principal aerodynamic, dynamic and control characteristics of SST and AST aircraft and their effect on the aircraft’s handling qualities. Finally, some possible solutions to the control and handling issues are investigated, assessed and presented.

Rotorcraft Handling Qualities Engineering: Managing the Tension between Safety and Performance 32nd Alexander A. Nikolsky Honorary Lecture

2013 ◽  
Vol 58 (1) ◽  
pp. 1-27 ◽  
Author(s):  
Gareth D. Padfield
Keyword(s):  
Flight Control ◽  
Performance Standards ◽  
Handling Qualities ◽  
System A ◽  
High Tension ◽  
Vital Component ◽  
Level 1 ◽  
And Performance ◽  
Control Technologies ◽  
And Control

In this Nikolsky paper, I look back nearly 70 years and highlight particular events that reflect the continual growth of the handling qualities discipline. This growth has brought us to a point where designers have, within their grasp, the performance standards, the criteria and test techniques, the understanding of rotorcraft aeromechanics and control, and the design tools, to ensure that handling deficiencies never again have to define the boundary of the operational flight envelope. This point is considered very important in the evolution of the discipline and the associated flight control technologies. The pilot is a vital component in the rotorcraft system; a nearly perfectly functioning component normally, but one that can be stressed, fatigued, or overloaded, particularly when dealing with the consequences of handing qualities deficiencies, and when managing high tension between flight performance and safety. It is argued that this tension is more manageable when an aircraft has good handling qualities, throughout all missions, including flight in degraded environments and hazardous operations. This paper tells the story of how our industry has arrived at this point, how the standards and the enabling technologies have developed, spurred by user needs, and enabled by research. The paper also looks forward, highlighting how we need to strive for super-Level 1 handling qualities, a state where pilot errors, in any shape or form attributable to deficient flight characteristics, are things of the past.

The role of copper ions in hydrogen peroxide bleaching: Their origin, removal, and effect on pulp quality

TAPPI Journal ◽  
2012 ◽  
Vol 11 (7) ◽  
pp. 37-46 ◽  
Author(s):  
PEDRO E.G. LOUREIRO ◽  
SANDRINE DUARTE ◽  
DMITRY V. EVTUGUIN ◽  
M. GRAÇA V.S. CARVALHO
Keyword(s):  
Hydrogen Peroxide ◽  
Copper Ions ◽  
Peroxide Bleaching ◽  
Metals Removal ◽  
Peroxide Decomposition ◽  
Equipment Corrosion ◽  
And Performance ◽  
And Control ◽  
Main Effects

This study puts particular emphasis on the role of copper ions in the performance of hydrogen peroxide bleaching (P-stage). Owing to their variable levels across the bleaching line due to washing filtrates, bleaching reagents, and equipment corrosion, these ions can play a major role in hydrogen peroxide decomposition and be detrimental to polysaccharide integrity. In this study, a Cu-contaminated D0(EOP)D1 prebleached pulp was subjected to an acidic washing (A-stage) or chelation (Q-stage) before the alkaline P-stage. The objective was to understand the isolated and combined role of copper ions in peroxide bleaching performance. By applying an experimental design, it was possible to identify the main effects of the pretreatment variables on the extent of metals removal and performance of the P-stage. The acid treatment was unsuccessful in terms of complete copper removal, magnesium preservation, and control of hydrogen peroxide consumption in the following P-stage. Increasing reaction temperature and time of the acidic A-stage improved the brightness stability of the D0(EOP)D1AP bleached pulp. The optimum conditions for chelation pretreatment to maximize the brightness gains obtained in the subsequent P-stage with the lowest peroxide consumption were 0.4% diethylenetriaminepentaacetic acid (DTPA), 80ºC, and 4.5 pH.

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