Incorporation of Passive Wing Folding in Flapping Wing Miniature Air Vehicles

2009 ◽  
Author(s):  
Dominik Mueller ◽  
John W. Gerdes ◽  
Satyandra K. Gupta
Keyword(s):  
Flapping Wing ◽  
Flight Behavior ◽  
Unique Challenge ◽  
Wing Motion ◽  
Air Resistance ◽  
Air Vehicle ◽  
Spatially Distributed ◽  
Turning Radius ◽  
Wing Folding ◽  
Aerodynamic Lift

Flapping wing motion produces positive lift in the down stroke and negative lift in the upstroke under zero forward velocity. Large birds frequently exhibit flight behavior where their wings are folded during the upstroke, thus lowering the air resistance as the wing is moved upwards. The result is reduced magnitude of negative lift produced during the upstroke, relative to the positive lift produced in the down stroke, where the wings are unfolded and the area is increased. We expect that by incorporating this style of upstroke wing folding into miniature air vehicle (MAV) platforms, beneficial flight properties would arise. Specifically, a portion of the wings’ overall lift will be generated by upstroke folding and downstroke unfolding, even at zero forward velocity. Such a capability will reduce the reliance on aerodynamic lift produced due to the forward motion of the MAV. This in turn would reduce the minimum flight-sustaining forward velocity and thus enhance MAV maneuverability by allowing for a reduced turning radius. Incorporating wing folding into a miniature air vehicle platform presents a unique challenge due to strict weight constraints present at small sizes. Using actuators to accomplish folding actively is not feasible due to the added weight of the actuators and the need for an on-board control system to synchronize the folding with the wing flapping motion. Therefore, the folding motion must be accomplished passively, since this is currently the only viable option in miniature MAVs. We have developed a passive, spatially distributed, one-way folding mechanism. This mechanism has been incorporated into a flying MAV testbed, and has successfully shown that the flapping wing MAV with folding wings is capable of flying at reduced forward velocity, while maintaining the payload carrying capacity.

Design of “Figure-8” Spherical Motion Flapping Wing for Miniature UAV

2009 ◽  
Author(s):  
Zohaib Rehmat ◽  
Jesse Roll ◽  
Joon S. Lee ◽  
Woosoon Yim ◽  
Mohamed B. Trabia
Keyword(s):  
Experimental Testing ◽  
Flapping Wing ◽  
Servo Motor ◽  
Flapping Motion ◽  
Experimental Prototype ◽  
Wing Motion ◽  
Air Vehicle ◽  
Spherical Motion

Hummingbirds and some insects exhibit a “Figure-8” flapping motion, which allows them to undergo variety of maneuvers including hovering. It is therefore desirable to have miniature air vehicle (FWMAV) with this wing motion. This paper presents a design of a flapping-wing for FWMAV that can mimic “Figure-8” motion using a spherical four bar mechanism. In the proposed design, the wing is attached to a coupler point on the mechanism, which is driven by a DC servo motor. A prototype is fabricated to verify that the design objectives are met. Experimental testing was conducted to determine the validity of the design. The results indicate good correlation between model and experimental prototype.

Design of a Bio-Inspired Spherical Four-Bar Mechanism for Flapping-Wing Micro Air-Vehicle Applications

2008 ◽  
Author(s):  
Matt McDonald ◽  
Sunil K. Agrawal
Keyword(s):  
Three Dimensional ◽  
Micro Air Vehicles ◽  
Aerodynamic Performance ◽  
Flapping Wing ◽  
Micro Air Vehicle ◽  
Aerodynamic Forces ◽  
Flapping Motion ◽  
Wing Motion ◽  
Air Vehicle ◽  
Flapping Mechanism

Design of flapping-wing micro air-vehicles presents many engineering challenges. As observed by biologists, insects and birds exhibit complex three-dimensional wing motions. It is believed that these unique patterns of wing motion create favorable aerodynamic forces that enable these species to fly forward, hover, and execute complex motions. From the perspective of micro air-vehicle applications, extremely lightweight designs that accomplish these motions of the wing, using just a single, or a few actuators, are preferable. This paper presents a method to design a spherical four-bar flapping mechanism that approximates a given spatial flapping motion of a wing, considered to have favorable aerodynamics. A spherical flapping mechanism was then constructed and its aerodynamic performance was compared to the original spatially moving wing using an instrumented robotic flapper with force sensors.

scholarly journals Characterizing and modeling the enhancement of lift and payload capacity resulting from thrust augmentation in a propeller-assisted flapping wing air vehicle

2017 ◽  
Vol 10 (1) ◽  
pp. 50-69 ◽  
Author(s):  
Alex E Holness ◽  
Hugh A Bruck ◽  
Satyandra K Gupta
Keyword(s):  
Mixed Mode ◽  
Aerodynamic Force ◽  
Force Production ◽  
Flight Time ◽  
Flapping Wing ◽  
Operating Conditions ◽  
Biologically Inspired ◽  
Air Vehicle ◽  
Payload Capacity ◽  
Aerodynamic Lift

Biologically-inspired flapping wing flight is attractive at low Reynolds numbers and at high angles of attack, where fixed wing flight performance declines precipitously. While the merits of flapping propulsion have been intensely investigated, enhancing flapping propulsion has proven challenging because of hardware constraints and the complexity of the design space. For example, increasing the size of wings generates aerodynamic forces that exceed the limits of actuators used to drive the wings, reducing flapping amplitude at higher frequencies and causing thrust to taper off. Therefore, augmentation of aerodynamic force production from alternative propulsion modes can potentially enhance biologically-inspired flight. In this paper, we explore the use of auxiliary propellers on Robo Raven, an existing flapping wing air vehicle (FWAV), to augment thrust without altering wing design or flapping mechanics. Designing such a platform poses two major challenges. First, potential for negative interaction between the flapping and propeller airflow reducing thrust generation. Second, adding propellers to an existing platform increases platform weight and requires additional power from heavier energy sources for comparable flight time. In this paper, three major findings are reported addressing these challenges. First, locating the propellers behind the flapping wings (i.e. in the wake) exhibits minimal coupling without positional sensitivity for the propeller placement at or below the platform centerline. Second, the additional thrust generated by the platform does increase aerodynamic lift. Third, the increase in aerodynamic lift offsets the higher weight of the platform, significantly improving payload capacity. The effect of varying operational payload and flight time for different mixed mode operating conditions was predicted, and the trade-off between the operational payload and operating conditions for mixed mode propulsion was characterized. Flight tests revealed the improved agility of the platform when used with static placement of the wings for various aerobatic maneuvers, such as gliding, diving, or loops.

Direct Sensing of Wing Flapping and Rotation Parameters for a Hawkmoth-Sized Flapping Wing Micro Air Vehicle

2016 ◽  
Author(s):  
Ranjana Sahai
Keyword(s):  
Optical Sensors ◽  
Flapping Wing ◽  
Advantages And Disadvantages ◽  
Wing Motion ◽  
Air Vehicle ◽  
Direct Sensing ◽  
Present Design ◽  
Rotation Parameters ◽  
Design Reasoning ◽  
Control Surfaces

Many insights can still be gained from the flapping flight of nature’s flyers, particularly from how they can effortlessly transition between flight modes and maneuver in obstacle-strewn environments. Furthermore, they are able to do this without the typical control surfaces found in manmade vehicles. Many theories have been postulated on how this is accomplished and they often involve control of individual wing position and stroke velocity. As such, direct sensing of wing motion both in flapping and in rotation would be desirable. In this work, we look at implementing wing motion sensing through the use of optical sensors. We develop sensing designs for both the transmissive and reflective sensor types, present design reasoning, and discuss the advantages and disadvantages of their use. Finally, we employ the sensors on the wing of a flapping wing MAV capable of power autonomous flight and demonstrate successful sensor tracking of general wing motion.

Experimental and analytical analysis of aerodynamic lift of an ornithopter at low and high angles of attack

2018 ◽  
Vol 233 (6) ◽  
pp. 2023-2031 ◽  
Author(s):  
Abdolbaghi Bakhtiari ◽  
Shahram Etemadi Haghighi ◽  
Adel Maghsoudpour
Keyword(s):  
Flapping Wing ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Type Method ◽  
Wing Motion ◽  
Two Dimensional Model ◽  
Element Type ◽  
High Angles Of Attack ◽  
Aerodynamic Lift ◽  
Blade Element

In this study, a model based on potential flow theory is developed to analyze the unsteady nonlinear aerodynamics of a flexible flapping wing at low and high angles of attack. It is assumed that the wing motion is composed of twisting and flapping. The developed unsteady two-dimensional model is applied to the flapping wing using a blade-element-type method. The computational model presented in this study shows better agreement with experimental data especially at a high angle of attack. Analytical results also show that the wings section does not necessarily twist linearly along the wingspan.

Design of a Bio-Inspired Spherical Four-Bar Mechanism for Flapping-Wing Micro Air-Vehicle Applications

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
Matt McDonald ◽  
Sunil K. Agrawal
Keyword(s):  
Three Dimensional ◽  
Micro Air Vehicles ◽  
Aerodynamic Performance ◽  
Flapping Wing ◽  
Micro Air Vehicle ◽  
Light Weight ◽  
Aerodynamic Forces ◽  
Wing Motion ◽  
Air Vehicle ◽  
Flapping Mechanism

The design of flapping-wing micro air-vehicles presents many engineering challenges. As observed by biologists, insects and birds exhibit complex three-dimensional wing motions. It is believed that these unique patterns of wing motion create favorable aerodynamic forces that enable these species to fly forward, hover, and execute complex motions. From the perspective of micro air-vehicle applications, extremely light-weight designs that accomplish these motions of the wing, using just a single or a few actuators, are preferable. This paper presents a method to design a spherical four-bar flapping mechanism that approximates a given spatial flapping motion of a wing, considered to have favorable aerodynamics. A spherical flapping mechanism was then constructed and its aerodynamic performance was compared to the original spatially moving wing using an instrumented robotic flapper with force sensors.

Design and Fabrication of an SU-8 Biomimetic Flapping-wing Micro Air Vehicle by MEMS Technology

ROBOT ◽  
2011 ◽  
Vol 33 (3) ◽  
pp. 366-370 ◽  
Author(s):  
Pengcheng CHI ◽  
Weiping ZHANG ◽  
Wenyuan CHEN ◽  
Hongyi LI ◽  
Kun MENG ◽  
...  
Keyword(s):  
Flapping Wing ◽  
Micro Air Vehicle ◽  
Air Vehicle ◽  
Mems Technology
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