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Active wing-pitching mechanism in hummingbird escape maneuvers
Previous studies suggested that wing pitching, i.e. the wing rotation around its long axis, of insects and hummingbirds is primarily driven by an inertial effect associated with stroke deceleration and acceleration of the wings and is thus passive. Here we considered the rapid escape maneuver of hummingbirds who were initially hovering but then startled by the frontal approach of a looming object. During the maneuver, the hummingbirds substantially changed their wingbeat frequency, wing trajectory, and other kinematic parameters. Using wing kinematics reconstructed from high-speed videos and computational fluid dynamics mo...
Source: Bioinspiration and Biomimetics - August 28, 2023 Category: Science Authors: Mohammad Nasirul Haque, Bo Cheng, Bret W Tobalske and Haoxiang Luo Source Type: research

Wing kinematics measurement and aerodynamics of hovering droneflies with wing damage
In this study, we performed successive unilateral and bilateral wing shearing to simulate wing damage in droneflies (Eristalis tenax) and measured the wing kinematics using high-speed photography technology. Two different shearing types were considered in the artificial wing damage. The aerodynamic force and power consumption were obtained by numerical method. Our major findings are the following. Different shearing methods have little influence on the kinematics, forces and energy consumption of insects. Following wing damage, among the potential strategies to adjust the three Euler angles of the wing, adjusting stroke an...
Source: Bioinspiration and Biomimetics - February 23, 2023 Category: Science Authors: Xueguang Meng, Xinyu Liu, Zengshuang Chen, Jianghao Wu and Gang Chen Source Type: research

Streamwise and lateral maneuvers of a fish-inspired hydrofoil
Fish are highly maneuverable compared to human-made underwater vehicles. Maneuvers are inherently transient, so they are often studied via observations of fish and fish-like robots, where their dynamics cannot be recorded directly. To study maneuvers in isolation, we designed a new kind of wireless carriage whose air bushings allow a hydrofoil to maneuver semi-autonomously in a water channel. We show that modulating the hydrofoil's frequency, amplitude, pitch bias, and stroke speed ratio (pitching speed of left vs right stroke) produces streamwise and lateral maneuvers with mixed effectiveness. Modulating pitch bias,...
Source: Bioinspiration and Biomimetics - August 24, 2021 Category: Science Authors: Qiang Zhong and Daniel B Quinn Source Type: research

Multimodal pipe-climbing robot with origami clutches and soft modular legs
In nature, climbing trees and pipes of varying diameters or even navigating inside of hollow pipes and tree holes is easy for some climbing animals and insects. However, today ’s pipe-climbing robots, which are important for automatically conducting periodic inspections and maintenance of pipelines to save time and keep humans away from hazardous environments, are designed mainly for a specific task, limiting their adaptability to different working scenarios and further implementation in real-life. In this paper, we propose a pipe-climbing robot with a soft linear actuator for bioinspired propulsion, two origami cl...
Source: Bioinspiration and Biomimetics - January 12, 2020 Category: Science Authors: Yongkang Jiang, Diansheng Chen, Hongying Zhang, Fr édéric Giraud and Jamie Paik Source Type: research

Mechanism and scaling of wing tone generation in mosquitoes
The generation of sound from flapping (i.e. wing tones) of mosquito ( Culex ) wings is investigated using computational modeling. The flow field around the wing is simulated by solving the incompressible Navier –Stokes equations using a sharp-interface immersed boundary method, and the aeroacoustic sound is predicted by the Ffowcs Williams and Hawkings equation using data from the aerodynamic simulations. In addition to the aerodynamics, the characteristics of mosquito ’s wing tone, spectral directivity patterns, and generation mechanisms are investigated. The effects of wing-beat frequency and stroke amplitude a...
Source: Bioinspiration and Biomimetics - December 3, 2019 Category: Science Authors: Jung-Hee Seo, Tyson L Hedrick and Rajat Mittal Source Type: research

Enhancing propulsion performance of a flexible heaving foil through dynamically adjusting its flexibility
This study investigates how dynamically adjusting the bending stiffness of a heaving foil affects its propulsion performance in a flow of Reynolds number 200. The foil is forced to oscillate sinusoidally at the leading edge, and its bending stiffness is tuned in a square-wave manner. Such a fluid-structure interaction (FSI) problem is explored using an immersed boundary lattice Boltzmann method (IBLBM) based numerical framework. The results reveal that when the lower and upper bounds of the foil ’s time-dependent bending stiffness are moderate, the net thrust can be evidently enhanced compared to those in the corre...
Source: Bioinspiration and Biomimetics - October 9, 2019 Category: Science Authors: Chenglei Wang, Feng Ren and Hui Tang Source Type: research

Development and flight performance of a biologically-inspired tailless flapping-wing micro air vehicle with wing stroke plane modulation
The tailless flapping-wing micro air vehicle (FW-MAV) is one of the most challenging problems in flapping-wing design due to its lack of tail for inherent flight stability. It must be designed in such a way that it can produce proper augmented control moments modulated by a closed-loop attitude controller for active stabilization. We propose a tailless FW-MAV with a wing stroke plane modulation mechanism, namely NUS-Roboticbird, which maneuvers by only using its flapping wings for both propulsion and attitude control. The flying vehicle has four wings comprised by two pairs, and each pair of wings and its stroke plan...
Source: Bioinspiration and Biomimetics - December 7, 2018 Category: Science Authors: Quoc-Viet Nguyen and Woei Leong Chan Source Type: research

Thrust force characterization of free-swimming soft robotic jellyfish
Five unique soft robotic jellyfish were manufactured with eight pneumatic network tentacle actuators extending radially from their centers. These jellyfish robots were able to freely swim untethered in the ocean, to steer from side to side, and to swim through orifices more narrow than the nominal diameter of the jellyfish. Each of the five jellyfish robots were manufactured with a different composition of body and tentacle actuator Shore hardness. A three-factor study was performed with these five jellyfish robots to determine the impact that actuator material Shore hardness, actuation frequency, and tentacle stroke...
Source: Bioinspiration and Biomimetics - September 17, 2018 Category: Science Authors: Jennifer Frame, Nick Lopez, Oscar Curet and Erik D Engeberg Source Type: research

Bio-inspired upper limb soft exoskeleton to reduce stroke-induced complications
Stroke has become the leading cause of disability and the second-leading cause of mortality worldwide. Dyskinesia complications are the major reason of these high death and disability rates. As a tool for rapid motion function recovery in stroke patients, exoskeleton robots can reduce complications and thereby decrease stroke mortality rates. However, existing exoskeleton robots interfere with the wearer ’s natural motion and damage joints and muscles due to poor human-machine coupling. In this paper, a novel ergonomic soft bionic exoskeleton robot with 7  degrees of freedom was proposed to address these problems...
Source: Bioinspiration and Biomimetics - August 23, 2018 Category: Science Authors: Ning Li, Tie Yang, Peng Yu, Junling Chang, Liang Zhao, Xingang Zhao, Imad H Elhajj, Ning Xi and Lianqing Liu Source Type: research

Lift and power in fruitflies in vertically-ascending flight
We measured the wing kinematics of fruitflies in both vertically-ascending and hovering flights and studied the aerodynamic forces and power in the two flight modes. The average ascending velocity is 0.45 m s −1 ; the stroke plane angle and the stroke frequency are the same as that in hovering flight, whilst the stroke amplitude is increased by 12% and the wing angle of attack in the latter half of a down- and upstroke both increased by 10%. Flow analysis shows that during ascending, the flies experience a downward inflow which reduces the effective angle of attack considerably. This problem is overcome by the incr...
Source: Bioinspiration and Biomimetics - July 30, 2018 Category: Science Authors: Chong Shen, Yanpeng Liu and Mao Sun Source Type: research

Wing-wake interaction destabilizes hover equilibrium of a flapping insect-scale wing
We present stability results for 152 simulations which consider different kinematics involving the pitch amplitude and pitch axis as well as the duration and timing of pitch rotation. The stability of all studied ...
Source: Bioinspiration and Biomimetics - June 14, 2017 Category: Science Authors: James Bluman and Chang-Kwon Kang Source Type: research

Asymmetries in wing inertial and aerodynamic torques contribute to steering in flying insects
Maneuvering in both natural and artificial miniature flying systems is assumed to be dominated by aerodynamic phenomena. To explore this, we develop a flapping wing model integrating aero and inertial dynamics. The model is applied to an elliptical wing similar to the forewing of the Hawkmoth Manduca sexta and realistic kinematics are prescribed. We scrutinize the stroke deviation phase, as it relates to firing latency in airborne insect steering muscles which has been correlated to various aerial maneuvers. We show that the average resultant force production acting on the body largely arises from wing pitch and roll...
Source: Bioinspiration and Biomimetics - June 7, 2017 Category: Science Authors: Mark Jankauski, T L Daniel and I Y Shen Source Type: research

Design and stable flight of a 21  g insect-like tailless flapping wing micro air vehicle with angular rates feedback control
An insect-like tailless flapping wing micro air vehicle (FW-MAV) without feedback control eventually becomes unstable after takeoff. Flying an insect-like tailless FW-MAV is more challenging than flying a bird-like tailed FW-MAV, due to the difference in control principles. This work introduces the design and controlled flight of an insect-like tailless FW-MAV, named KUBeetle. A combination of four-bar linkage and pulley-string mechanisms was used to develop a lightweight flapping mechanism that could achieve a high flapping amplitude of approximately 190 °. Clap-and-flings at dorsal and ventral stroke reversals wer...
Source: Bioinspiration and Biomimetics - April 3, 2017 Category: Science Authors: Hoang Vu Phan, Taesam Kang and Hoon Cheol Park Source Type: research

Passive mechanism of pitch recoil in flapping insect wings
The high torsional flexibility of insect wings allows for elastic recoil after the rotation of the wing during stroke reversal. However, the underlying mechanism of this recoil remains unclear because of the dynamic process of transitioning from the wing rotation during stroke reversal to the maintenance of a high angle of attack during the middle of each half-stroke, when the inertial, elastic, and aerodynamic effects all have a significant impact. Therefore, the interaction between the flapping wing and the surrounding air was directly simulated by simultaneously solving the incompressible Navier –Stokes equation...
Source: Bioinspiration and Biomimetics - December 19, 2016 Category: Science Authors: D Ishihara and T Horie Source Type: research

Wing and body kinematics of forward flight in drone-flies
Here, we present a detailed analysis of the wing and body kinematics in drone-flies in free flight over a range of speeds from hovering to about 8.5 m s −1 . The kinematics was measured by high-speed video techniques. As the speed increased, the body angle decreased and the stroke plane angle increased; the wingbeat frequency changed little; the stroke amplitude first decreased and then increased; the ratio of the downstroke duration to the upstroke duration increased; the mean positional angle increased at lower speeds but changed little at speeds above 3 m s −1 . At a speed above about 1.5 m s −1 , wing rotat...
Source: Bioinspiration and Biomimetics - August 13, 2016 Category: Science Authors: Xue Guang Meng and Mao Sun Source Type: research

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