Spring-Assisted Motorized Transmission for Efficient Hover by Four Flapping Wings

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
Yao-Wei Chin ◽  
Ziyuan Ang ◽  
Yukai Luo ◽  
Woei-Leong Chan ◽  
Javaan S. Chahl ◽  
...  
Keyword(s):  
High Speed ◽  
Beat Frequency ◽  
Electrical Power ◽  
Micro Air Vehicles ◽  
Flapping Wings ◽  
Direct Drive ◽  
Flexible Wings ◽  
Speed Reduction ◽  
Brushless Motor ◽  
Lower Disk

Elastic storage has been reported to help flying insects save inertial power when flapping their wings. This motivates recent research and development of elastic storage for flapping-wing micro air vehicles (fwMAVs) and their ground (tethered) flight tests. The previous designs of spring-loaded transmissions are relatively heavy or bulky; they have not yet been adopted by freely hovering prototypes of fwMAVs, especially those with four flapping wings. It is not clear if partial elastic storage can still help save power for flapping flight while not overloading the motorized transmission. Here, we developed ultralight and compact film hinges as elastic storage for four flapping wings. This spring-assisted transmission was motor driven such that the wing beat frequency was higher than the natural frequency of elastically hinged wings. Our experiments show that spring recoil helps accelerate wing closing thus generating more thrust. When powered by a 3.18 g brushless motor, this 13.4 g fwMAV prototype with spring-assisted transmission can take off by beating four flexible wings (of 240 mm span) with up to 21–22 g thrust generation at 22–23 Hz. Due to lower disk loading and high-speed reduction, indirect drive of the four elastically hinged wings can produce a thrust per unit of electrical power of up to 4.6 g/W. This electrical-power-specific thrust is comparable to that generated by direct drive of a propeller, which was recommended by the motor (AP-03 7000kv) manufacturer.

Efficient flapping wing drone arrests high-speed flight using post-stall soaring

2020 ◽  
Vol 5 (44) ◽  
pp. eaba2386 ◽  
Author(s):  
Yao-Wei Chin ◽  
Jia Ming Kok ◽  
Yong-Qiang Zhu ◽  
Woei-Leong Chan ◽  
Javaan S. Chahl ◽  
...  
Keyword(s):  
High Speed ◽  
Electrical Power ◽  
Flapping Wing ◽  
Flapping Wings ◽  
Direct Drive ◽  
Wing Membrane ◽  
Air Speed ◽  
Lift And Drag ◽  
Smooth Transitions ◽  
High Thrust

The aerobatic maneuvers of swifts could be very useful for micro aerial vehicle missions. Rapid arrests and turns would allow flight in cluttered and unstructured spaces. However, these decelerating aerobatic maneuvers have been difficult to demonstrate in flapping wing craft to date because of limited thrust and control authority. Here, we report a 26-gram X-wing ornithopter of 200-millimeter fuselage length capable of multimodal flight. Using tail elevation and high thrust, the ornithopter was piloted to hover, fly fast forward (dart), turn aerobatically, and dive with smooth transitions. The aerobatic turn was achieved within a 32-millimeter radius by stopping a dart with a maximum deceleration of 31.4 meters per second squared. In this soaring maneuver, braking was possible by rapid body pitch and dynamic stall of wings at relatively high air speed. This ornithopter can recover to glide stability without tumbling after a 90-degree body flip. We showed that the tail presented a strong stabilizing moment under high thrust, whereas the wing membrane flexibility alleviated the destabilizing effect of the forewings. To achieve these demands for high thrust, we developed a low-loss anti-whirl transmission that maximized thrust output by the flapping wings to 40 grams in excess of body weight. By reducing the reactive load and whirl, this indirect drive consumed 40% less maximum electrical power for the same thrust generation than direct drive of a propeller. The triple roles of flapping wings for propulsion, lift, and drag enable the performance of aggressive flight by simple tail control.

THE PARALLEL CRANK-ROCKER FLAPPING MECHANISM: AN INSECT-INSPIRED DESIGN FOR MICRO AIR VEHICLES

2007 ◽  
Vol 04 (04) ◽  
pp. 625-643 ◽  
Author(s):  
ANDREW T. CONN ◽  
STUART C. BURGESS ◽  
SENG LING CHUNG
Keyword(s):  
High Speed ◽  
Beat Frequency ◽  
Unsteady Aerodynamics ◽  
Micro Air Vehicles ◽  
Indoor Environments ◽  
Insect Wing ◽  
Wing Kinematics ◽  
System A ◽  
Flying Robot ◽  
Flapping Mechanism

This paper presents a novel micro air vehicle (MAV) design that seeks to reproduce the unsteady aerodynamics of insects in their natural flight. The challenge of developing an MAV capable of hovering and maneuvering through indoor environments has led to bio-inspired flapping propulsion being considered instead of conventional fixed or rotary winged flight. Insects greatly outperform these conventional flight platforms by exploiting several unsteady aerodynamic phenomena. Therefore, reproducing insect aerodynamics by mimicking their complex wing kinematics with a miniature flying robot has significant benefits in terms of flight performance. However, insect wing kinematics are extremely complex and replicating them requires optimal design of the actuation and flapping mechanism system. A novel flapping mechanism based on parallel crank-rockers has been designed that accurately reproduces the wing kinematics employed by insects and also offers control for flight maneuvers. The mechanism has been developed into an experimental prototype with MAV scale wings (75 mm long). High-speed camera footage of the non-airborne prototype showed that its wing kinematics closely matched desired values, but that the wing beat frequency of 5.6 Hz was below the predicted value of 15 Hz. Aerodynamic testing of the prototype in hovering conditions was completed using a load cell and the mean lift force at the maximum power output was measured to be 23.8 mN.

scholarly journals Investigation of a New Flux-Modulated Permanent Magnet Brushless Motor for EVs

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ying Fan ◽  
Lingling Gu ◽  
Yong Luo ◽  
Xuedong Han ◽  
Ming Cheng
Keyword(s):  
High Speed ◽  
Simple Structure ◽  
Static Characteristics ◽  
Direct Drive ◽  
Element Analysis ◽  
Torque Density ◽  
Brushless Motor ◽  
Design Requirements ◽  
High Torque ◽  
Compact Design

This paper presents a flux-modulated direct drive (FMDD) motor. The key is to integrate the magnetic gear with the PM motor while removing the gear inner-rotor. Hence, the proposed FMDD motor can achieve the low-speed high-torque output and high-speed compact design requirements as well as high-torque density with a simple structure. The output power equation is analytically derived. By using finite element analysis (FEA), the static characteristics of the proposed motor are obtained. Based on these characteristics, the system mathematical model can be established. Hence, the evaluation of system performances is conducted by computer simulation using the Matlab/Simulink. A prototype is designed and built for experimentation. Experimental results are given to verify the theoretical analysis and simulation.

Development of Sensor-Less Power-Assisted System with Disturbance Observer Considering High Friction

2013 ◽  
Vol 25 (6) ◽  
pp. 1020-1028
Author(s):  
Takanori Miyoshi ◽  
◽  
Ryosuke Imai ◽  
Kazuhiko Terashima ◽  
Kanemitsu Ochiai ◽  
...  
Keyword(s):  
High Power ◽  
Disturbance Observer ◽  
High Speed ◽  
Static Friction ◽  
Force Sensor ◽  
Direct Drive ◽  
Speed Reduction ◽  
Drive Motor ◽  
Support Device ◽  
Friction Parameters

Japan has a dwindling birthrate and a rapidly aging population, which has led to an increasing number of elderly laborers. Although this has spurred development into power-assisted (PA) equipment that can reduce the physical demands, most of power assisted systems developed so far have used the force sensor, a direct drive motor, or a high power motor. The PA machine using force sensor is unable to detect and avoid obstacles that might collide with nonsensor components of the machine. The direct drive motor is too expensive for the practical use and its power tends to increase. According to Japanese law, a high power motor is not allowed to cooperate together with laborers in the factory. Thus, in this research, a sensor-less power-assisted (PA) system capable of estimating operator force based on a disturbance observer and friction correction is designed and built for a high friction production support device using a lowcapacity servo motor and a high-speed reduction ratio reducer. First, a dynamic model of a production support device is identified with specific friction parameters. Next, a sensor-less PA system is constructed that is equipped with an appropriate disturbance observer and dynamic friction correction. Moreover, the static friction issues are solved by the regular driving command. Finally, the accuracies of estimated force are examined, and the effectiveness of the constructed sensor-less PA system is verified.

Bio-Mimetic Millimeter-Scale Flapping Wings for Micro Air Vehicles

2009 ◽  
Author(s):  
Christopher Kroninger ◽  
Jeffrey Pulskamp ◽  
Jessica Bronson ◽  
Ronald G. Polcawich ◽  
Eric Wetzel
Keyword(s):  
Micro Air Vehicles ◽  
Flapping Wings ◽  
Air Vehicles

Design and control of a high-speed direct-drive manipulator

1989 ◽  
Vol 27 (3) ◽  
pp. 375-394 ◽  
Author(s):  
K. YOUCEF-TOUMI ◽  
A. T. Y. KUO
Keyword(s):  
High Speed ◽  
Direct Drive ◽  
And Control

Betadine has a ciliotoxic effect on ciliated human respiratory cells

2014 ◽  
Vol 129 (S1) ◽  
pp. S45-S50 ◽  
Author(s):  
J H Kim ◽  
J Rimmer ◽  
N Mrad ◽  
S Ahmadzada ◽  
R J Harvey
Keyword(s):  
Epithelial Cells ◽  
High Speed ◽  
Imaging System ◽  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Positive Control ◽  
Clinical Dose ◽  
Significant Difference ◽  
Sinonasal Mucosa ◽  
Ciliary Beat

AbstractObjective:This study investigated the effect of Betadine on ciliated human respiratory epithelial cells.Methods:Epithelial cells from human sinonasal mucosa were cultured at the air–liquid interface. The cultures were tested with Hanks' balanced salt solution containing 10 mM HEPES (control), 100 µM ATP (positive control), 5 per cent Betadine or 10 per cent Betadine (clinical dose). Ciliary beat frequency was analysed using a high-speed camera on a computer imaging system.Results:Undiluted 10 per cent Betadine (n = 6) decreased the proportion of actively beating cilia over 1 minute (p < 0.01). Ciliary beat frequency decreased from 11.15 ± 4.64 Hz to no detectable activity. The result was similar with 5 per cent Betadine (n = 7), with no significant difference compared with the 10 per cent solution findings.Conclusion:Betadine, at either 5 and 10 per cent, was ciliotoxic. Caution should be applied to the use of topical Betadine solution on the respiratory mucosal surface.

Finite-Element Analysis of the Magnetostatic Field of a Coaxial Magnetic Gear Device

2015 ◽  
Vol 764-765 ◽  
pp. 289-293
Author(s):  
Yi Chang Wu ◽  
Han Ting Hsu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Magnetic Flux ◽  
High Speed ◽  
Field Analysis ◽  
Element Analysis ◽  
Magnetostatic Field ◽  
Speed Reduction ◽  
Dimensional Finite Element ◽  
Magnetic Gear

This paper presents the magnetostatic field analysis of a coaxial magnetic gear device proposed by Atallah and Howe. The structural configuration and speed reduction ratio of this magnetic gear device are introduced. The 2-dimensional finite-element analysis (2-D FEA), conducted by applying commercial FEA software Ansoft/Maxwell, is performed to evaluate the magnetostatic field distribution, especially for the magnetic flux densities within the outer air-gap. Once the number of steel pole-pieces equals the sum of the pole-pair numbers of the high-speed rotor and the low-speed rotor, the coaxial magnetic gear device possesses higher magnetic flux densities, thereby generating greater transmitted torque.

The Kinematics of Swimming in Larvae of the Clawed Frog, Xenopus Laevis

1986 ◽  
Vol 122 (1) ◽  
pp. 1-12 ◽  
Author(s):  
KARIN VON SECKENDORFF HOFF ◽  
RICHARD JOEL WASSERSUG
Keyword(s):  
Xenopus Laevis ◽  
Swimming Speed ◽  
High Speed ◽  
Total Mass ◽  
Beat Frequency ◽  
Maximum Amplitude ◽  
Open Water ◽  
Computer Assisted ◽  
Anuran Larvae ◽  
Tail Beat

The kinematics of swimming in larval Xenopus laevis has been studied using computer-assisted analysis of high-speed (200 frames s−1) ciné records. The major findings are as follows. 1. At speeds below 6 body lengths (L) per second, tail beat frequency is approximately 10 Hz and, unlike for most aquatic vertebrates, is not correlated with specific swimming speed. At higher speeds, tail beat frequency and speed are positively correlated. 2. Xenopus tadpoles show an increase in the maximum amplitude of the tail beat with increasing velocity up to approximately 6Ls−1. Above that speed amplitude approaches an asymptote at 20 % of body length. 3. Anterior yaw is absent at velocities below 6Ls−1, unlike for other anuran larvae, but is present at higher speeds. 4. At speeds below 6Ls−1 there is a positive linear relationship between length of the propulsive wave (λ) and specific swimming speed. At higher speeds wavelength is constant at approximately 0.8L. 5. There is a shift in the modulation of wavelength and tail beat frequency with swimming speed around 5.6Ls−1, suggesting two different swimming modes. The slower mode is used during open water cruising and suspension feeding. The faster, sprinting mode may be used to avoid predators. 6. Froude efficiencies are similar to those reported for fishes and other anuran larvae. 7. Unlike Rana and Bufo larvae, the axial muscle mass of Xenopus increases dramatically with size from less than 10% of total mass for the smallest animals to more than 45% of total mass for the largest animals. This increase is consistent with maintaining high locomotor performance throughout development.

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