Flapping Wing Mechanism Research Articles

English

This paper presents the simulation of flapping-wing unmanned aerial vehicle model using X-plane and Matlab/ Simulink. The flapping-wing ornithopter model (i.e. an aircraft that flies by flapping its wings) has been developed in plane maker software and executed in the X-plane environment. The key idea of flapping-wing mechanism in X-plane software is by varying its dihedral angle sinusoidally. This sinusoidally varying dihedral angle of wing creates upward and downward stroke moments inturn this creates a lift and a forward thrust for flying the flapping-wing model. Here pitch, roll, yaw and throttle (flapping rate) is fed as reference input through the user datagram protocol (UDP) port. The difference between the reference inputs, the simulated outputs are again fed back to simulator through UDP port and the gains are observed for the responses of flapping-wing unmanned aerial vehicle in Matlab/Simulink environment. Here various gains are used to monitor the optimized flying of flapping-wing model. Defence Science Journal, Vol. 64, No. 4, July 2014, pp.327-331, DOI:http://dx.doi.org/10.14429/dsj.64.4933

Effect of torsional stiffness and inertia on the dynamics of low aspect ratio flapping wings

Micro air vehicle-motivated aerodynamics in biological flight has been an important subject in the past decade. Inspired by the novel flapping wing mechanisms in insects, birds and bats, we have carried out a numerical study systematically investigating a three-dimensional flapping rigid wing with passively actuated lateral and rotational motion. Distinguishing it from the limited existing studies, this work performs a systematic examination on the effects of wing aspect ratio (AR = 1.0 to infinity), inertia (density ratio σ = 4–32), torsional stiffness (frequency ratio F = 1.5–10 and infinity) and pivot point (from chord-center to leading edge) on the dynamics response of a low AR rectangular wing under an initial zero speed flow field condition. The simulation results show that the symmetry breakdown of the flapping wing results in a forward/backward motion with a rotational pitching. When the wing reaches its stable periodic state, the induced pitching frequency is identical to its forced flapping frequency. However, depending on various kinematic and dynamic system parameters, (i.e. flapping frequency, density ratio and pitching axis), the lateral induced velocity shows a number of different oscillating frequencies. Furthermore, compared with a one degree of freedom (DoF) wing in the lateral direction only, the propulsion performance of such a two DoF wing relies very much on the magnitude of torsional stiffness adding on the pivot point, as well as its pitching axis. In all cases examined here, thrust force and moment generated by a long span wing is larger than that of a short wing, which is remarkably linked to the strong reverse von Kármán vortex street formed in the wake of a wing.

Bionic Flexible Wings Design of the Flapper

The fixed-wing aircrafts rely mainly on thrust generated by engine and lift produced by wings to keep flying, so there are strict requirements on their speeds and attack angles. The flappers can hover freely in the air like insects because they have different flight principles and forms compared with fixed-wing aircrafts. The flapper is consisted of the flapping-wing, the flapping-wing mechanism and the drive. The flapping-wing is used to generate lifts and thrusts while the wing mechanism and the drive provide main power to the flapping wing. Traditionally, flapper uses rigid wing to provide lift and thrust force. The researches of the insect flapping wing process indicate insect wings would produce certain flexibility and umbrella effect in this process. Based on the above research, the compression molding is employed to manufacture the bionic flexible wing in this article. Whats more, in order to imitate the umbrella deformations at the wing tips, IPMC (Ionic Polymer Metal-Composites) are fixed on the flexible wings to achieve umbrella deformations.

Design of a Foldable Flapping Mechanism

Folding motion is important for a flight creature using flapping wing mode, but it seldom used for flapping-wing robot. In this paper, we propose a new foldable flapping wing mechanism, which consists of spatial crank-rocker mechanism, parallelogram mechanism, and cam mechanism. We establish the kinematical models, calculate the optimal parameters, and set up the virtual prototype using 3D software. The tracks of wingtip and the comparison between foldable and unfoldable flap wing show that folding motion can improve lift force obviously.

A Conceptual Model of Flapping-Wing Mechanism Inspired from the Results of Numerical Study

This paper investigates the aerodynamic forces of several plunging wing models by means of computational fluid dynamics. A finite volume method was used to solve the two-dimensional unsteady incompressible Navier-Stokes equations. The forces and power efficiency have been calculated and compared between sets of different models. Current work found that the nonsymmetrical moving can enhance the lift and thrust forces. The numerical results also prove that the flexible wing model can be use to improve the efficiency and reduce the input. Additionally, a new conceptual model for flapping wing mechanism with active deformation and adaptive nonsymmetrical driving motion is proposed base on the numerical results.

Monolithic SUEX Flapping Wing Mechanisms for Pico Air Vehicle Applications

This paper develops a simple flapping wing mechanism fabricated monolithically from an epoxy-based negative photoresist (SUEX) dry film. The developed fabrication process has fewer steps compared to other methods, does not use precious metals, and greatly reduces processing time and cost. It simultaneously defines the pico air vehicle (PAV) airframe, compliant flapping mechanism, and artificial insect wing using photolithography. Using this process, we designed and fabricated the LionFly, a flapping wing mechanism actuated by a PZT-5H bimorph actuator. Rapid prototypes were fabricated with precisely defined features and material properties and geometry that are similar to insects. We present the fabrication process and characterization of SUEX and show that flexure thickness can be controlled by 310 nm UV dose. Static and dynamic modeling of the LionFly have excellent agreement with experimental data. Performance from multiple prototypes shows devices with resonance frequency of 49.13 ± 1.43 Hz and up to 75° peak to peak flapping angle demonstrating applicability of the fabrication process for flapping wing PAV applications.

A Simulation and Design Tool for a Passive Rotation Flapping Wing Mechanism

This paper develops a numerical simulation tool for designing passive rotation flapping wing mechanisms. The simulation tool includes a quasi-static model of the piezoelectric actuator bending, transmission kinematics, and the small Reynolds number aerodynamic forces governing wing dynamics. To validate the developed tool, two single-wing systems with distinct resonant frequencies are manufactured and characterized. Comparison to experimental results reveals that, although discrepancies exist, the simulation is able to predict general trends of wing kinematics and lift behavior as functions of frequency, thus, being useful as a design tool. Finally, the complex models, ranging from actuator deflection to wing aerodynamics presented in this paper, allow analysis of the complete system revealing insight into several wing trajectory control methodologies, and potentially serving as a design and optimization tool for future flapping wing robots.

Wing rotation and lift in SUEX flapping wing mechanisms

This research presents detailed modeling and experimental testing of wing rotation and lift in the LionFly, a low cost and mass producible flapping wing mechanism fabricated monolithically from SUEX dry film and powered by piezoelectric bimorph actuators. A flexure hinge along the span of the wing allows the wing to rotate in addition to flapping. A dynamic model including aerodynamics is developed and validated using experimental testing with a laser vibrometer in air and vacuum, stroboscopic photography and high definition image processing, and lift measurement. The 112 mg LionFly produces 46° flap and 44° rotation peak to peak with 12° phase lag, which generates a maximum average lift of 71 μN in response to an applied sinusoidal voltage of 75 V AC and 75 V DC at 37 Hz. Simulated wing trajectories accurately predict measured wing trajectories at small voltage amplitudes, but slightly underpredict amplitude and lift at high voltage amplitudes. By reducing the length of the actuator, reducing the mechanism amplification and tuning the rotational hinge stiffness, a redesigned device is simulated to produce a lift to weight ratio of 1.5.

Flapping Wing Micro Air Vehicle Bench Test Setup

The purpose of this research was to develop testing methods that can be used to determine the forces, moments, and deflections involved in flapping wing aerodynamics. To pursue the research, a flapping wing mechanism and wings with spans ranging from 9.1 inches to 12.1 inches were built. A variety of mechanisms, capable of, alternatively, purely flapping, flapping with pitch, and flapping with pitch and out-of-plane motion were conceptualized and drawn using solid modeling software. Two of the simpler designs, a single degree-of-freedom flapping mechanism and the two-degree of freedom flapping mechanism were fabricated using a rapid prototype 3-D printer, and sustained operation was demonstrated. A thrust stand and a six-component force balance were used to gather force data from the flapping-only mechanism, combined with a variety of wing shapes. Four high-speed cameras were used to capture the motion of the wings. To minimize intrusiveness an array of laser dots was projected onto the wing during flapping and photogrammetry software was used to analyze the images and determine a shape profile of the wing composed of a frame and membrane during flapping. While the focus of this research was on the bench test setup development, some insight into the influence of wing design on the forces acting on the mechanism was gained.

A Differentially Driven Flapping Wing Mechanism for Force Analysis and Trajectory Optimization

Flapping flight has the potential to revolutionize micro air vehicles (MAVs) due to increased aerodynamic performance, improved maneuverability, and hover capabilities. This paper presents the design of a robotic flapping wing mechanism for use in general studies involving flapping flight and laboratory-based experimental optimization of flapping trajectories. The design allows for dynamic adjustment of flapping trajectories in air or liquids with three rotational degrees of freedom on each wing. The design, instrumentation, and control of the mechanism are discussed, and experimental characterization of the mechanism's performance is presented. Preliminary trajectory optimization using a Box-Behnken design approach is used and shows successful parameter optimization. The limitations of the current mechanism are addressed. A survey of flapping mechanisms is presented.

Large Displacement Flexible Micro Actuators

This paper discusses a major application of flexible micro actuators in Micro Air Vehicles (MAV). Design, Kinematics, flapping patterns, performance tests of flapping wing mechanism which replicates dragonfly and corresponding results are discussed in this paper. This paper also discusses artificial foldable wing models by mimicking the unfolding/folding of beetle hind wing in which the actuation is triggered by electrically activated Shape Memory Alloy (SMA) wires.

Topology Structure Design of 12 Flapping-Wing Mechanisms

People used the Micro Air Vehicles to patrol the military activity or explore the danger region.The important parts of Micro Air Vehicles are the flapping-wing mechanisms those can simulate the wing-motion of flying being.Hence this work is to present a systematic approach for designing new flapping-wing mechanisms with one degree of freedom that can simulate the wing-motion of long ear bats and insects.First,we analyze the topological structure and motion characteristics of existed flapping mechanisms.Then, the design criteria of the topological structure are described.Based on the design criteria of topology, the methodology of mechanism design is applied to synthesize new flapping-wing mechanisms. Finally, this research of the provide method can obtain 12 new flapping -wing mechanisms and one prototype of a flying insect mechanism.

Passive torque regulation in an underactuated flapping wing robotic insect

Recent developments in millimeter-scale fabrication processes have led to rapid progress towards creating airborne flapping wing robots based on Dipteran (two winged) insects. Previous work to regulate forces and torques generated by flapping wings has focused on controlling wing trajectory. An alternative approach uses underactuated mechanisms with tuned dynamics to passively regulate these forces and torques. The resulting ‘mechanically intelligent’ devices execute wing trajectory corrections to realize desired body forces and torques without the intervention of an active controller. This article describes an insect-scale flapping wing mechanism consisting of a single piezoelectric actuator, an underactuated transmission, and passively rotating wings. Wing stroke velocities are passively modulated to eliminate net airframe roll torque. A theoretical model predicts lift generating wing trajectories and quantifies the passive reduction in roll torque. An experimental structure provides an at-scale demonstration of passive torque regulation.

Based on Pro/E on the Design and Simulation of Bionic Dragonfly Flapping Wing Aircraft

In order to design an efficient, reliable, light weight, flapping wing mechanism,Improve the flight performance of the micro air vehicle and expand its application areas,this paper is concerned on the design and simulation of bionic dragonfly flapping wing aircraft .An mechanism design to simulate the movement of dragonfly wings isr presented in this paper.Then, simulation and analysis are made based on Pro/E.

Kinematic and experimental aerodynamic characterisation of the RotaFlap – a novel flapping wing mechanism

AbstractA unique patented mechanism, termed ‘RotaFlap’, which can move its wings in a figure-eight shape kinematically similar to insects or hummingbirds, has been investigated through the design, construction, integration and testing of various prototypes. In this paper, the most recent prototype is presented whereby the RotaFlap kinematics is characterised to understand some of its most pertinent parameters. A host of variations have been identified and in this study a subset of these have been tested. A preliminary characterisation of the force production, especially the vertical lift coefficient, has been completed. It is concluded that this mechanism produces vertical lift coefficient values similar to insect and hummingbird flight for similar Reynolds numbers.

Force Measurements and Flow Visualization for a Flexible Flapping Wing Mechanism

This paper describes a series of experiments using a flapping wing mechanism. Force measurements were combined with high speed photography for two sets of flexible wings. The aerodynamic forces generated by flexible membrane type wings were measured using a two degree of freedom force balance constructed during the course of these experiments which measured the aerodynamic forces of lift and thrust. Lift and thrust measurements were acquired as the mechanism flapped the flexible wings for multiple cases, and the two most interesting conditions were explored in more detail. These two conditions consisted of a zero velocity free stream condition and a forward flight condition of 5 m/s. For these two conditions, high-speed video of the flapping wing was taken. The images from the video were also correlated with cycle averaged aerodynamic forces produced by the mechanism. Several observations were made regarding the behavior of flexible flapping wings that should aid in the design of future flexible flapping wing vehicles. In addition, flow visualization images were taken of the flapping wing under forward flight condition and flow field velocity vectors were calculated.

Co-simulation and experimental study for wingspan of flapping wing micro aerial vehicle

The 3D model of flapping wing mechanism and veins is constructed in 3D computer aided design (CAD) software UG. Then the co-simulation model is established by using multibody dynamics software ADAMS and MATLAB. The validation of this co-simulation model is verified by comparing the simulation results with final experiments. The simulation results and experiments reveal that the relation between flapping frequency and driving voltage of motor is approximately linear under various wingspans. The variance of flapping frequency among different wingspans augments gradually with increasing voltage. Furthermore, the simulation results suggest that flapping frequency is sensitive to wingspan and decreases with increasing wingspan of veins, and the relation between flapping frequency and moment of inertia of veins is also approximately linear for various voltages.

Design of an active flapping wing mechanism and a micro aerial vehicle using a rotary actuator

Abstract We present an active flapping wing mechanism that generates four flapping patterns and a prototype micro aerial vehicle (MAV). The mechanism, a modified slider-crank (MSC), uses a rotary actuator and generates active rotation and flapping of wings. The kinematics, flapping patterns, enhancements of the mechanism and prototype steering are presented. The effectiveness of the mechanism has been demonstrated by developing a prototype of size 200 mm × 200 mm × 150 mm, weighing 3.2 g, capable of constrained hover and forward flight using external power.

Two-Dimensional Aerodynamic Models of Insect Flight for Robotic Flapping Wing Mechanisms of Maximum Efficiency

In the “modified quasi-steady” approach, two-dimensional (2D) aerodynamic models of flapping wing motions are analyzed with focus on different types of wing rotation and different positions of rotation axis to explain the force peak at the end of each half stroke. In this model, an additional velocity of the mid chord position due to rotation is superimposed on the translational relative velocity of air with respect to the wing. This modification produces augmented forces around the end of each stroke. For each case of the flapping wing motions with various combination of controlled translational and rotational velocities of the wing along inclined stroke planes with thin figure-of-eight trajectory, discussions focus on lift-drag evolution during one stroke cycle and efficiency of types of wing rotation. This “modified quasi-steady” approach provides a systematic analysis of various parameters and their effects on efficiency of flapping wing mechanism. Flapping mechanism with delayed rotation around quarter-chord axis is an efficient one and can be made simple by a passive rotation mechanism so that it can be useful for robotic application.

Materials challenges in the design of an insect-like flapping wing mechanism based on a four-bar linkage

This paper describes materials challenges, and how they were met, in the design of a four-bar linkage mechanism driving a test-bed for an insect-like flapping wing micro air vehicle. In the design process, both aerodynamic and dynamic simulations were made, but could not resolve all uncertainties regarding the forces acting on the mechanism. This difficulty was resolved by a combination of: (1) a simulation parametric study; (2) an experimental programme devised according to the results of the study; (3) by the use of carbon/epoxy composite for critical elements. Application of carbon/epoxy composites not only allowed to overcome uncertainties, but also provided a potential for future research and development. A complete mechanism was manufactured, assembled and tested; it works reliably and generates useful data for further aeromechanical research.