Feathering Motion Research Articles

Synthesis of Drive Systems of Flapping and Feathering Motions for Bird-like Robot using Twist Drive Mechanism

Synthesis of Drive Systems of Flapping and Feathering Motions for Bird-like Robot using Twist Drive Mechanism

Experimental analysis of the sweepback angle effect on the thrust generation of a robotic penguin wing

Penguins have evolved excellent swimming skills as diving birds, benefiting from their agile wings. This paper experimentally analyzes the effects of the wing sweepback angle on thrust generation using a robotic penguin wing. A developed wing mechanism that can realize penguin-like flapping and feathering motion was used for actuating five alternative wing models, with different sweepback angles ranging from 0° to 50°. Force measurements under a steady water flow were conducted for both fixed and flapping states for all wing models. The results showed that small sweepback angles of 30° or less in the fixed state caused a steep lift curve and a moderate sweepback angle of 30° produced the largest lift-to-drag ratio. In the flapping state, the smaller sweepback wings generated a larger net thrust for the same wing motion, whereas the larger-sweepback wings produced more thrust under the same Strouhal number. The findings also revealed that larger sweepback wings more easily achieve the maximum net thrust in terms of less angle-of-attack control. In contrast, the hydrodynamic efficiency was not greatly affected by the sweepback. Regardless of the sweepback, the trend of the efficiency increasing with increasing flow speed indicates that the penguin wings can be more suitable for high-speed locomotion for higher hydrodynamic efficiency.

A novel 3-DoF piezoelectric robotic pectoral fin: design, simulation, and experimental investigation

The fish pectoral fins, which play a vital role for fish swimming mobility, can perform three degree-of-freedom movements (rowing, feathering, and flapping motions), promoting that a lot of bionic robotic pectoral fins have been proposed and developed. However, these developed robotic pectoral fins driven by electromagnetic motors or smart materials still cannot fully realize the aforementioned three movement modes. To solve this problem, a novel piezoelectric robotic pectoral fin based on the converse piezoelectric effect and friction drive principle is proposed in this study, to achieve the three motion modes. Using a piezoelectric actuator, the robotic pectoral fin can be driven to move with three degree-of-freedom motion modes. Firstly, the overall structures of the proposed piezoelectric robotic pectoral fin and the designed piezoelectric actuator are explained in detailed. Additionally, a finite element simulation and a combination of vibration measurement and impedance analysis experiments are carried out to verify the effectiveness of the proposed piezoelectric actuator. Finally, an experimental investigation is conducted to evaluate output performances of the robotic pectoral fin prototype. Experimental results indicated that (a) the maximum average velocities of the rowing and flapping motions of the pectoral fin prototype under an excitation voltage of 550 Vpp are 290 and 241.7 deg s−1, respectively, and the maximum rotation speed of the feathering motion is 6.03 deg s−1; (b) the maximum output forces of the rowing and flapping motions of the pectoral fin are 2.156 and 2.107 N, respectively; (c) rowing motion start stop response times are 13 and 10.6 ms, flapping motion start and stop response times are 14.2 and 9.2 ms, and feathering motion start/stop response times are 34 and 56.8 ms, respectively.

Biomimetic Realization of a Robotic Penguin Wing: Design and Thrust Characteristics

Flapping flippers or fins are widely employed in biomimetic and bioinspired aquatic robots that imitate natural swimmers, such as fish and dolphins. This article involves robotic biomimetics of the penguin, which is often overlooked as an excellent swimmer benefiting from agile wings. To achieve equivalent swimming skills in an aquatic robot, the wing motion of a real penguin was investigated. Based on the findings, we developed a three-DOF robotic penguin wing that is able to implement the same flapping, feathering, and pitch motions as in natural penguins. A kinematic analysis is presented, and the generation of swimming motions is demonstrated. We designed experiments to study the thrust characteristics of the motion of each joint. The results suggest that the flapping motion generates the main thrust during locomotion and the pitch angle can effectively change the thrust direction while the feathering motion enables active control of the angle of attack (AoA). According to the results, stalling of the wing occurs near an AoA of 10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> in the steady state; however, the feathering motion can avoid the stall and boost the net thrust by a factor of up to 7 relative to the net thrust without active feathering. Furthermore, the introduction of the feathering motion reduces the torque required to actuate the flapping motion. The hydrodynamics of the wing in different flow states are also discussed.

The dynamics of passive feathering rotation in hovering flight of bumblebees

The fluid–structure interaction problem of the flapping wings of bumblebees is considered, with focus on the action of elastic joints between wings and body. Morphological measurements and kinematic reconstruction of the wing motion using synchronized high-speed video recordings are described. They provide the necessary input data for numerical modeling. In particular, for the first time, the moments of inertia of bumblebee’s wing are determined using realistic mass distribution. A computational fluid dynamics solver is combined with a dynamical model that describes the wing motion. The model consists of the wings approximated as flat plates, connected with the body by elastic hinges. The results of high-resolution numerical simulations are presented. The hinged plate model produces realistic feathering motion and accurate time-average estimates of the aerodynamic performance in hover, despite some discrepancy in the instantaneous values of aerodynamic forces compared with the fully prescribed model. A parameter sweep reveals that the hinge is not exactly tuned to maximum efficiency during hovering flight, but slightly offset away from the maximum.

Control of Flow around an Oscillating Plate for Lift Enhancement by Plasma Actuators

During insect flight, a feathering motion of the wing’s controls vortex shedding for lift enhancement. In this study, in order to control the flow around a wing flapping with simplified sinusoidal motion, plasma actuators were introduced to simplify the complex feathering motion. In a wind tunnel, a smoke-wire method was enacted to visualize the flow fields around an oscillating plate with an attack angle of 4° in a uniform flow for the baseline and controlled cases. The actuator placed around the leading edge was found to suppress the flow separation on the top surface. Numerical simulations were performed to investigate the control effects on the fluctuating lift, where the control effects by the intermittently driven actuator were also predicted. The actuator installed on the top surface throughout the up-stroke motion was found to suppress vortex shedding from the trailing edge, which resulted in an 11% lift enhancement compared to the baseline case. In regard to the effects of the installation position, it was found that the actuator placed on the top surface was effective, compared to the cases for installation on the bottom surface or both surfaces.

トンボの翅の変形特性が飛翔に与える影響

Dragonflies have high flight performance in spite of small size. Therefore, applying flight mechanism of dragonfly to micro air vehicle is expected. One of the important thing for dragonfly flight is characteristics of wings. Dragonfly wing is passively deformed in the tip side from the nodus in flapping flight. Wing deformation is thought to correspond to feathering motion. However, dragonfly perform a feathering motion actively. It is necessary for development of MAV to understand the interaction between active and passive feathering. In this study, the effect of passive deformation of the wing on aerodynamic force in flapping flight with feathering motions was investigated using fluid-structure interaction analysis. In this analysis, nodus wing models, which can deform passively, and rigid wing model, which cannot deform, are used. Feathering angle is three types: 0, 20, and 40 deg. As a result, when the feathering angle is 20 deg or less, lift force of the nodus wings is increased. Moreover, drag force of the nodus wings is decreased when the feathering angle is 20 deg. However, when the feathering angle is 40 deg, overlarge deformation of wing decreases lift force and increases drag force. Power for flapping of nodus wings is reduced compared with rigid wing. In the case of straight flight, efficiency of lift is best when the feathering angle is 20 deg and nodus is located near the center of wings.

マンタ型ロボットのヒレのひねり角制御による停止特性

In this paper, Manta-like robot is proposed to perform the fin with flapping and feathering motion. In the case of rigid fin controlled by feathering angle, stopping performance is evaluated by time response from the initial swimming velocity for flapping frequency. The swimming velocity increases for the frequency of the flapping motion. After reaching the maximum velocity, the feathering angle is controlled in the decreasing velocity period. The result shows that the feathering angle control for the Manta-like robot is effective to stopping motion in the water.

J0220402 トンボの羽ばたき運動の変化が空気力に与える影響([J022-04]生物規範メカニクス・システム:生物の運動、力学及びミメティクスセッション(4))

Dragonflies show unique and superior flight performance than other species of insect and bird. Dragonflies move their wings twist feathering motion when they fly. They can fly highly, stop suddenly, turn sharply, or whatever by changing their feathering motion. We observed dragonfly's straight flight and hovering, and we found difference of feathering angle between their straight flight and hovering. In this study, we made flap experimental equipment which can change its feathering motion, and we measured lift and thrust forces by using it. Moreover, we also visualized around wings of the flap experimental equipment by using baby powder, and we observed velocity of powders with Particle Image Velocimetry (PINT) measurement software. From experimental results, value of lift and thrust and backwash were varied by changing the feathering angle of the wing. Consequently, it was found that dragonfly controls the lift and thrust by changing the feathering angle of the wing.

1P1-G08 マンタ型水中ロボットのひねり動作付き振動翼による推進性能(水中ロボット・メカトロニクス(2))

1P1-G08 マンタ型水中ロボットのひねり動作付き振動翼による推進性能(水中ロボット・メカトロニクス(2))

2A1-X05 羽ばたき機構の検討と試作機の評価(バイオロボティクス)

Two four-flapping-wing type robot prototypes using crank mechanisms were produced for this study. Their flapping aerodynamic characteristics were assessed. Their aerodynamics were measured and flapping motion mechanisms were evaluated. Based on those results fundamental design consideration was performed. We produced polyethylene film membranous wings of two kinds whose trailing edge were made free experimentally. These membrane wings performed a natural feathering motion with a flapping motion. We visualize and observed the air flow around the wing circumference using wind tunnel experiments with steam while changing the robot posture angle. As described herein, we present some results of our study.

1202 蚊の羽ばたき飛行のメカニズム解明のための拡大翅モデル実験 : 曲げ剛性を考慮した翅モデルによるフェザリング運動の模擬とその流力特性(OS12 生物・生体に関する流れ,OS12 生物・生体に関する流れ)

The purpose of this study is elucidating the mechanism of mosquito's flight. The motion of mosquito's wings consists of three representative motion; flapping, lead-lug and feathering motion. The feathering motion is a rotational movement which is centering on a wing leading edge. The mosquitoes are performing this motion passively produced by fluid forces and so on. In order to build the enlarged model which simulates this motion, we need to measure the stiffness of the mosquito's wings. The bending stiffness of the mosquito's wings were measured by the experiment using a cantilever. The enlarged wing model was designed based on its results. We observed the flapping motion of the enlarged wing model in the very low velocity wind tunnel and verified whether the feathering motion can be simulated.

1150 A NUMERICAL FLOW ANALYSIS AROUND THE FLAPPING WING OF A DRAGONFLY WITH FLUID-STRUCTURE INTERACTION

The veins of the dragonfly's wing are so complex that the local elasticity of the wing varies with the position on the wing. We herein propose a new model for the estimation of elasticity of the dragonfly wing in which the elasticity of the vein is approximated by the elasticity of a circular cylinder having the same volume as the vein at the divided cell on the wing. In flexible cases, constant elasticity, the linear change along the span and the chord of the wing and the proposed equivalent model are computed. We investigate the velocity and pressure fields around the flapping wing induced by an elastic wing with a heaving and feathering motion using unsteady finite element method - finite difference method (FEM-FDM) coupling analysis in a non-inertial coordinate frame.

Special Section on Intelligent Unmanned Systems

There has been increased worldwide interest in the research on intelligent unmanned systems in recent decades. The unmannedsystem technologies have been implemented in the underwater, ground, aerial, and space domains within an ever-extending operational envelope. The miniaturization of the hardware footprint coupled with exponentially increased computing power has enabled more efficient application of a wide range of unmanned vehicles. The papers in this special section represent recent contributions to several aspects of intelligent unmanned systems. The papers were largely an extension of select papers presented at the ICIUS2010 held in Bali, Indonesia, in October 2010. Three papers deal with the development of intelligent algorithms for unmanned aerial vehicles, while two papers focus on the software and hardware integration. The rest of the papers cover the application of aerospace technology for unmanned-vehicle design. The paper by Manathara and Ghose addresses the problem of multiple unmanned aerial vehicle (UAV) rendezvous when the UAVs have to perform maneuvers to avoid collisions with other UAVs. The authors proposed a solution that consists of velocity control and a wandering maneuver of the UAVs based on a consensus among them on the estimated time of arrival at the point of rendezvous. This simple algorithm was shown to be useful in tracking stationary or slowly moving targets with a standoff distance. Kim et al. paper present an automatic landing control design using adaptive, integrated guidance and control (IGC) logic. The proposed IGC design uses a combination of an adaptive output feedback inversion and backstepping techniques. The authors formulated the problem as an adaptive output feedback control problem for a line-of-sight–based chasing-flight configuration. The automatic landing system using IGC logic was evaluated using a sophisticated six-degrees-of-freedom nonlinear simulation program with the approach and landing scenario. Jeong et al. focused on the design of a robust H-infinity attitude controller for an unmanned small-scale helicopter. It was demonstrated that the H-infinity controller works amiably when applied to the nonlinear model, even though it is designed using a linear model approximation. The time-domain simulation with the nonlinear model demonstrated that the proposed controller was very robust to the uncertainties as expected, overcoming large gain uncertainties and time delay in each input channel. Formal verification currently plays an important role in guaranteeing the correctness of the operation of safety-critical systems, for example, in UAVs. Lee et al. discuss formal modeling and verification of operational flight programs (OFPs) in a small-scale unmanned helicopter. Two different formal models for the OFP were developed and verified using SPIN and UPPAAL model checkers. Real-time behavior of theOFPwas specified using a timed-automata model. Their verification of the OFP found several safety-critical faults to be reported to and fixed by the development team. One of the key features of autonomous flight of UAVs is the ability to perform localization and map building of flight environments simultaneously. Park et al. present vision-based simultaneous localization and mapping (SLAM) for small UAVs in global-positioningsystem–denied environments. A method that combines onboard and on-ground localization and mapping was proposed. The paper by Thu et al. investigates the nature of vortex structure developed by a double-delta wing. Dye-flow visualization in a small-scale water tunnel was used for the study. The authors identified two types of flow interaction, which are enveloping and coiling-up modes. Characteristics of the two modes were examined for various angles of attack (AOAs) at relatively low Reynolds numbers of 10,000 and 15,000. The authors found that the wing vortex became stronger and the enveloping mode was dominant for a low AOA, while the coiling-up mode was dominant at a high AOA. They also reported that the transition of these two modes occurred at around an AOA of 20 . Another paper in the special section studied the unsteady flow field of a flapping model butterfly under the zero-advance ratio (J 5 0) condition using timeresolved stereoscopic particle image velocimetry. The effect of feathering on thrust generation because of chordwise wing flexibility was identified by focusing on the ejection of airflow from the gap between two wings. Ghosh et al. found that the wing flexibility adds a feathering effect and enhances net lift and thrust generation through ejection of vortex pairs during the downstroke-to-upstroke–motion reversal. They also reported that the thrust produced was positive all over the cycle, even at J 5 0, because of the feathering motion. The special section editors would like to express their sincerest gratitude to all the contributing authors. We hope that the readers will find the content of this section not only relevant but also stimulating and beneficial for their ongoing research endeavors.

Unsteady Wake Characteristics of a Flapping Wing through 3D TR-PIV

AbstractThe unsteady wake characteristics of a butterfly-shaped wing undergoing flapping and feathering motions are studied. A 4-bar quick return mechanism is used to generate the flapping motion. To achieve considerable feathering motion, the leading edge of the wing is fixed to the flapping arm of the model, while the trailing edge of the wing is kept free to bend and deform out of weight and aerodynamic loading. The flapping frequency and wing size considered for this study cover rotational Reynolds numbers of 6,040–10,080 for a zero advance ratio. The three-dimensional (3D) (stereoscopic) time-resolved (TR) velocity field is measured to understand the dynamics of the lift and thrust generation. The conservation of momentum principle has been used to estimate the thrust force from the particle image velocimetry (PIV) results. The mean velocity profiles in the wake show the frequency dependence ejection of the trailing edge vortex, which is believed to be effectively used for thrust production and maneu...

Effects of Flapping Wing Kinematics on Hovering and Forward Flight Aerodynamics

The effects of wing kinematics on the aerodynamic characteristics of a flapping insect wing are investigated experimentally. The time-varying aerodynamic forces acting on the flapping wing are measured in hovering and forward flight using a dynamically scaledmechanicalmodel in awater tunnel, which simulates a bumblebee flapping wing in hovering and forward flight. Wing kinematics can be categorized as trapezoidal or sinusoidal types. The trapezoidal flapping motion is divided into translational and reversal phases, and the trapezoidal feathering motion is divided into fixed-angle and rotational phases. In the sinusoidal type, the time histories of angles for the flapping and feathering motions are represented as sinusoidal functions. The feathering rotation during the flapping translation causes an increase in aerodynamic power rather than lift and thrust for hovering and forward flight. Therefore, it is preferable for the feathering rotation to be conducted during the flapping reversal phase for high efficiency. The trapezoidal flapping motion and trapezoidal feathering motion with a shorter duration of rotation should be selected for a higher efficiency in hovering and forward flight. This result indicates thatmany insects using the trapezoidal type attach importance to a good efficiency in selecting the wing kinematics. For a larger lift in hovering and slower forward flight, the sinusoidal flappingmotion and trapezoidal featheringmotion with a shorter duration of rotation should be selected.

Resonance Type Flapping Wing for Micro Air Vehicle

A resonance type flapping wing, which is suitable for an insect like Micro Air Vehicle, is presented. It utilizes the r esonance phenomenon of a two-degrees of freedom elastic system, that is, the wing is suppor ted by the spr ings for flapping and feathering motions, being oscillated, at the resonance frequency of the system, only by the torque in flapping motion. The amplitudes of flapping and feathering motions and the phase angle between them are controlled by changing the amount of the damping. Optimum design method is applied to determine the structural parameters of the wing, amount of the torque and damping. Using these optimum quantities thus determined, the arbitrary control of the flapping and feather ing motions becomes possible. The paper presents the theoretical bases of the concept, and the results of the numer ical simulation using a Navier-Stokes code, which takes into account the aeroelastic effects, are also presented to verify the concept.

917 フェザリング運動を取り入れた羽ばたき推進式4枚翼型飛行機に関する研究(GS ロボティクスII)

917 フェザリング運動を取り入れた羽ばたき推進式4枚翼型飛行機に関する研究(GS ロボティクスII)

J0205-2-3 外骨格の弾性変形による羽ばたき機構の開発([J0205-2]バイオメカニズム/バイオミメティクス/バイオインスパイアー(2))

The purpose of this study is to develop a Micro Air Vehicle based on an insect's flapping motion that can be used as an explorer in special environments. We constructed the prototype mechanism of the flapping motion by using the elastic deformation of the exoskeleton and applying the principle of leverage. In this mechanism, the vibration generated from the solenoid was transmitted to the exoskeleton, and the wing was moved indirectly. The phosphor bronze, 0.2mm in thickness, was used to form an exoskeleton frame and the wing rods. This mechanism enabled two degree of freedom of movement. In this paper, we compared the flapping and feathering motions of the prototype compared with those of the natural insect.

E33 フェザリング運動を取り入れた4枚翼型羽ばたき機に関する研究(E3 ロボット・制御(飛行体))

E33 フェザリング運動を取り入れた4枚翼型羽ばたき機に関する研究(E3 ロボット・制御(飛行体))