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Article
Publication date: 26 July 2013

Hoon Cheol Park, Eko Priamadi and Quang‐Tri Truong

The aim of this paper is to investigate the effect of wing kinematics change on force generation produced by flapping wings.

Abstract

Purpose

The aim of this paper is to investigate the effect of wing kinematics change on force generation produced by flapping wings.

Design/methodology/approach

Forces produced by flapping wings are measured using a load cell and compared for the investigation. The measured forces are validated by estimation using an unsteady blade element theory.

Findings

From the measurement and estimation, the authors found that flapping wings produced positive and negative lifts when the wings are attached with the +30° and −30°, respectively.

Research limitations/implications

The authors quantified the characteristics of change in the force generation by flapping wings for three wing kinematics. The wing kinematics was modified by changing the initial wing attachment angle.

Practical implications

The result may be applicable to design of control mechanism for an insect‐mimicking flapping‐wing micro air vehicle, which has only wings without control surfaces at its tail.

Social implications

The preliminary work may provide an insight for design strategy of flapping‐wing micro air vehicles with compact and handy configurations, because they may perform controlled flight even without control surfaces at their tails.

Originality/value

The work included here is the first attempt to quantify the force generation characteristics for different wing kinematics. The suggested way of wing kinematics change can provide a concept for control mechanism of a flapping‐wing micro air vehicle.

Details

International Journal of Intelligent Unmanned Systems, vol. 1 no. 3
Type: Research Article
ISSN: 2049-6427

Keywords

Article
Publication date: 9 February 2015

Hoang Vu Phan, Quang-Tri Truong and Hoon-Cheol Park

The purpose of this paper is to demonstrate the uncontrolled vertical takeoff of an insect-mimicking flapping-wing micro air vehicle (FW-MAV) of 12.5 cm wing span with a body…

Abstract

Purpose

The purpose of this paper is to demonstrate the uncontrolled vertical takeoff of an insect-mimicking flapping-wing micro air vehicle (FW-MAV) of 12.5 cm wing span with a body weight of 7.36 g after installing batteries and power control.

Design/methodology/approach

The forces were measured using a load cell and estimated by the unsteady blade element theory (UBET), which is based on full three-dimensional wing kinematics. In addition, the mean aerodynamic force center (AC) was determined based on the UBET calculations using the measured wing kinematics.

Findings

The wing flapping frequency can reach to 43 Hz at the flapping angle of 150°. By flapping wings at a frequency of 34 Hz, the FW-MAV can produce enough thrust to over its own weight. For this condition, the difference between the estimated and average measured vertical forces was about 7.3 percent with respect to the estimated force. All parts for the FW-MAV were integrated such that the distance between the mean AC and the center of gravity is close to zero. In this manner, pitching moment generation was prevented to facilitate stable vertical takeoff. An uncontrolled takeoff test successfully demonstrated that the FW-MAV possesses initial pitching stability for takeoff.

Originality/value

This work has successfully demonstrated an insect-mimicking flapping-wing MAV that can stably takeoff with initial stability.

Details

International Journal of Intelligent Unmanned Systems, vol. 3 no. 1
Type: Research Article
ISSN: 2049-6427

Keywords

Article
Publication date: 31 August 2022

Mostafa Arasteh, Yegane Azargoon and M.H. Djavareshkian

Ground effect is one of the important factors in the enhancement of wing aerodynamic performance. This study aims to investigate the aerodynamic forces and performance of a…

Abstract

Purpose

Ground effect is one of the important factors in the enhancement of wing aerodynamic performance. This study aims to investigate the aerodynamic forces and performance of a flapping wing with the bending deflection angel under the ground effect.

Design/methodology/approach

In this study, the wing and flapping mechanism were designed and manufactured based on the seagull flight and then assembled. It is worth noting that this mechanism is capable of wing bending in the upstroke flight as big birds. Finally, the model was examined at bending deflection angles of 0° and 107° and different distances from the surface, flapping frequencies and velocities in forward flight in a wind tunnel.

Findings

The results revealed that the aerodynamic performance of flapping wings in forward flight improved due to the ground effect. The effect of the bending deflection mechanism on lift generation was escalated when the flapping wing was close to the surface, where the maximum power loading occurred.

Practical implications

Flapping wings have many different applications, such as maintenance, traffic control, pollution monitoring, meteorology and high-risk operations. Unlike fixed-wing micro aerial vehicles, flapping wings are capable of operating in very-low Reynolds-number flow regimes. On the other hand, ground effect poses positive impacts on the provision of aerodynamic forces in the take-off process.

Originality/value

Bending deflection in the flapping motion and ground effect are two influential factors in the enhancement of the aerodynamic performance of flapping wings. The combined effects of these two factors have not been studied yet, which is addressed in this study.

Details

Aircraft Engineering and Aerospace Technology, vol. 95 no. 4
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 12 June 2020

David J. Talarico, Aaron Mazzeo and Mitsunori Denda

Advancements in aerospace technologies, which rely on unsteady fluid dynamics, are being hindered by a lack of easy to use, computationally efficient unsteady computational fluid…

Abstract

Purpose

Advancements in aerospace technologies, which rely on unsteady fluid dynamics, are being hindered by a lack of easy to use, computationally efficient unsteady computational fluid dynamics (CFD) software. Existing CFD platforms are capable of handling unsteady flapping, but the time, money and expertise required to run even a basic flapping simulation make design iteration and optimization prohibitively expensive for the average researcher.

Design/methodology/approach

In the present paper, a remedy to model the effects of viscosity is introduced to the original vortex method, in which the pitching moment amplitude grew over time for simulations involving multiple flapping cycles. The new approach described herein lumps far-field wake vortices to mimic the vortex decay, which is shown to improve the accuracy of the solution while keeping the pitching moment amplitude under control, especially for simulations involving many flapping cycles.

Findings

In addition to improving the accuracy of the solution, the new method greatly reduces the computation time for simulations involving many flapping cycles. The solution of the original vortex method and the new method are compared to published Navier–Stokes solver data and show very good agreement.

Originality/value

By utilizing a novel unsteady vortex method, which has been designed specifically to handle the highly unsteady flapping wing problems, it has been shown that the time to compute a solution is reduced by several orders of magnitude (Denda et al., 2016). Despite the success of the vortex method, especially for a small number of flapping cycles, the solution deteriorates as the number of flapping cycles increases due to the inherent lack of viscosity in the vortex method.

Details

International Journal of Intelligent Unmanned Systems, vol. 8 no. 3
Type: Research Article
ISSN: 2049-6427

Keywords

Article
Publication date: 30 March 2010

Sanjay K. Boddhu and John C. Gallagher

The purpose of this paper is to present an approach to employ evolvable hardware concepts, to effectively construct flapping‐wing mechanism controllers for micro robots, with the…

Abstract

Purpose

The purpose of this paper is to present an approach to employ evolvable hardware concepts, to effectively construct flapping‐wing mechanism controllers for micro robots, with the evolved dynamically complex controllers embedded in a, physically realizable, micro‐scale reconfigurable substrate.

Design/methodology/approach

In this paper, a continuous time recurrent neural network (CTRNN)‐evolvable hardware (a neuromorphic variant of evolvable hardware) framework and methodologies are employed in the process of designing the evolution experiments. CTRNN is selected as the neuromorphic reconfigurable substrate with most efficient Minipop Evolutionary Algorithm, configured to drive the evolution process. The uniqueness of the reconfigurable CTRNN substrate preferred for this study is perceived from its universal dynamics approximation capabilities and prospective to realize the same in small area and low power chips, the properties which are very much a basic requirement for flapping‐wing based micro robot control. A simulated micro mechanical flapping insect model is employed to conduct the feasibility study of evolving neuromorphic controllers using the above‐mentioned methodology.

Findings

It has been demonstrated that the presented neuromorphic evolvable hardware approach can be effectively used to evolve controllers, to produce various flight dynamics like cruising, steering, and altitude gain in a simulated micro mechanical insect. Moreover, an appropriate feasibility is presented, to realize the evolved controllers in small area and lower power chips, with available fabrication techniques and as well as utilizing the complex dynamics nature of CTRNNs to encompass various controls ability in a architecturally static hardware circuit, which are more pertinent to meet the constraints of micro robot construction and control.

Originality/value

The proposed neuromorphic evolvable hardware approach along with its modules intact (CTRNNs and Minipop) can provide a general mechanism to construct/evolve dynamically complex and optimal controllers for flapping‐wing mechanism based micro robots for various environments with least human intervention. Further, the evolved neuromorphic controllers in simulation study can be successfully transferred to its hardware counterpart without sacrificing its anticipated functionality and realized within a predictable area and power ranges.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 3 no. 1
Type: Research Article
ISSN: 1756-378X

Keywords

Article
Publication date: 3 September 2019

Joaquin Ortega-Casanova and Ramon Fernandez-Feria

This paper aims to consider the thrust force generated by two plunging and pitching plates in a tandem configuration in forward flight to find out the configuration that maximizes…

Abstract

Purpose

This paper aims to consider the thrust force generated by two plunging and pitching plates in a tandem configuration in forward flight to find out the configuration that maximizes the propulsive efficiency with high-enough time-averaged lift force.

Design/methodology/approach

To that end, the Navier–Stokes equations for the incompressible and two-dimensional flow at Reynolds number $500 are solved. As the number of parameters is quite large, the case of constant separation between the plates (half their chord length), varying seven non-dimensional parameters related to the phase shift between the heaving motion of the foils, the phase lag between pitch and heave of each plate independently and the frequency and amplitude of the heaving and pitching motions are considered. This analysis complements some other recent studies where the separation between the foils has been used as one of the main control parameters.

Findings

It is found that the propulsive efficiency is maximized for a phase shift of 180° (counterstroking), when the reduced frequency is 2.2 and the Strouhal number based on half the plunging amplitude is 0.17, the pitching amplitude is 25° and when pitch leads heave by 135° in both the fore -plate and the hind plate. The propulsive efficiency is about 20 per cent, just a bit larger than that of an isolate plate with the same motion as the fore-plate, but the corresponding lift force is negligible for a single plate. The paper discusses this vortical flow structure in relation to other less efficient ones. Finally, the effect of the separation between the plates and the Reynolds number is also briefly discussed.

Originality/value

The kinematics of two flapping plates in tandem configuration that maximizes the propulsive efficiency are characterized discussing physically the associated vortical flow structures in comparison with less efficient kinematic configurations. A much larger number of parameters in the optimization procedure than in previous related works is considered.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 11
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 3 July 2017

Andrzej Tarnowski

This paper aims to describe the concept of morphing tailless aircraft with discontinuous skin and its preliminary kinematic solution. Project assumptions, next steps and expected…

Abstract

Purpose

This paper aims to describe the concept of morphing tailless aircraft with discontinuous skin and its preliminary kinematic solution. Project assumptions, next steps and expected results are briefly presented.

Design/methodology/approach

Multidisciplinary numerical optimization will be used to determine control allocation for wing segments rotation. Wing demonstrator will be fabricated and tested in wind tunnel. Results will be used in construction of flying model and design of its control system. Flight data of morphing demonstrator and reference aircraft will result in comparative analysis of both technologies.

Findings

Proposed design combines advantages of wing morphing without complications of wing’s structure elastic deformation. Better performance, stability and maneuverability is expected due to wing’s construction which is entirely composed of unconnected wing segments. Independent control of each segment allows for free modeling of spanwise lift force distribution.

Originality/value

Nonlinear multipoint distribution of wing twist as the only mechanism for control and flight performance optimization has never been studied or constructed. Planned wind tunnel investigation of such complex aerodynamic structure has not been previously published and will be an original contribution to the development of aviation and in particular to the aerodynamics of wing with discontinuous skin.

Details

Aircraft Engineering and Aerospace Technology, vol. 89 no. 4
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 9 August 2018

Arpan Das and Shaligram Tiwari

Growing application of micro aerial vehicle (MAV) sets in demand for accurate computations of low Reynolds number flows past their wings. The purpose of this study is to…

Abstract

Purpose

Growing application of micro aerial vehicle (MAV) sets in demand for accurate computations of low Reynolds number flows past their wings. The purpose of this study is to investigate the effect of unsteady freestream velocity or wind gust on a harmonically plunging symmetric NACA0012 airfoil at Re = 1,000. The influence of unsteady parameters, such as reduced frequency of plunging motion (0.25 < k < 1.5), non-dimensional plunging amplitude (ho = 0.2) and non-dimensional amplitude of wind gust (0.1 = λ = 0.4) has been studied.

Design/methodology/approach

Computations have been carried out using commercial software ANSYS Fluent 16.0. To incorporate the plunging motion, the entire reference frame is oscillating, and thereby, a source term is added in the Navier–Stokes equation.

Findings

The results have been presented in the form of streamlines, vorticity contours, lift and drag signals and their spectra. It is observed that the ratio of plunging frequency to gust frequency (f/fg) has strong influence on periodic characteristics of unsteady wake. It has also been observed that for a fixed plunging amplitude, an increase in value of k results into a change from positive drag to thrust.

Practical implications

The research has implications in the development of MAV.

Originality/value

This study is intended to get a better understanding of unsteady parameters associated with gusty flow in flapping wing applications and possible ways to alleviate its adverse effect on it.

Details

Aircraft Engineering and Aerospace Technology, vol. 90 no. 7
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 25 February 2014

Chao Liu, Jing Liu, Li Xu and Wei Xiang

Entomology is a useful tool when applied to engineering challenges that have been solved in nature. Especially when these special abilities of olfactory sensation, vision…

Abstract

Purpose

Entomology is a useful tool when applied to engineering challenges that have been solved in nature. Especially when these special abilities of olfactory sensation, vision, auditory perception, fly, jump, navigation, chemical synthesis, exquisite structure and others were connected with mechanization, informationization and intelligentization of modern science and technology, and produced innumerable classical bionic products. The paper aims to discuss these issues.

Design/methodology/approach

All kinds of special abilities of insects and application status have been described and discussed in order to summarize the advanced research examples and supply bibliographic reference to the latters. Future perspectives and challenges in the use of insect bionics were also given.

Findings

In the period of life sciences and information sciences, insect bionics not only promoted the development of modern science and technology on the sides of mechanics, molecule, energy, information and control greatly but also provided new ideas and technologies for the crisis of science and technology, food, environment and ecosystem.

Originality/value

It may provide strategies to solve the problems and be a source of good ideas for researchers.

Article
Publication date: 18 March 2022

Zihao Chen, Weiping Zhang, Jiawang Mou and Kexin Zheng

Vertical take-off is commonly adopted in most insect-mimicking flapping-wing micro air vehicles (FMAV) while insects also adopt horizontal take-off from the ground. The purpose of…

Abstract

Purpose

Vertical take-off is commonly adopted in most insect-mimicking flapping-wing micro air vehicles (FMAV) while insects also adopt horizontal take-off from the ground. The purpose of this paper is to study how insects adjust their attitude in such a short time during horizontal take-off by means of designing and testing an FMAV based on stroke plane modulation.

Design/methodology/approach

An FMAV prototype based on stroke plane rotating modulation is built to test the flight performance during horizontal take-off. Dynamic gain and decoupling mixer is added to compensate for the nonlinearity during the rotation angle of the stroke plane getting too large at the beginning of take-off. Force/torque test based on a six-axis sensor validates the change of aerodynamic force and torque at different rotation angles. High-speed camera and motion capture system test the flight performance of horizontal take-off.

Findings

Stroke plane modulation can provide a great initial pitch toque for FMAV to realize horizontal take-off. But the large range of rotation angles causes nonlinearity and coupling of roll and yaw. A dynamic gain and a mixer are added in the controller, and the FMAV successfully achieves horizontally taking off in less than 1 s.

Originality/value

The research in this paper shows stroke plane modulation is suitable for insect’s horizontal take-off

Details

Aircraft Engineering and Aerospace Technology, vol. 94 no. 7
Type: Research Article
ISSN: 1748-8842

Keywords

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