著者

HASHEM M.M.A Keigo WATANABE Kiyotaka IZUMI

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME International Journal Series C Mechanical Systems, Machine Elements and Manufacturing (ISSN:13447653)

巻号頁・発行日

vol.41, no.3, pp.406-412, 1998-09-15 (Released:2008-02-18)

参考文献数

12

被引用文献数

2 5

---

Evolution strategies(ESs)are search algorithms which imitate the principles of natural evolution as a method to solve parameter optimization problems numerically.The effectiveness and simplicity of ES algorithms have lead many people to believe that they are the methods of choice for difficult, real-life problems superseding traditional search techniques.However, the inherent strength of the ES algorithms largely depends upon the choice of a suitable crossover and mutation technique in their application domains.This paper discusses a new ES in which both a subpopulationbased arithmetical crossover(SBAC)and a time-variant mutation(TVM)operator are used.the SBAC operator explores promising areas in the search space with different directivity while the TVM operator exploits fast(but not premature)convergence with high precision results.Thus, a balance between exploration and exploitation is achieved in the evolutionary process with these combined efforts.The TVM also acts as a fine local tuner at the converging stages for high precision solutions.Its action depends upon the age of the populations, and its performance is quite different from the Uniform Mutation(UM)operation.The efficacy of the proposed methods is illustrated by solving discrete-time optimal control models which are frequently used in the applications.

著者

Shigenobu KUBO Yoshitaka CHIKAZAWA Hiroyuki OHSHIMA Masato UCHITA Takayuki MIYAGAWA Masao ETO Tetsuji SUZUNO Ichiyo MATOBA Junji ENDO Osamu WATANABE Koichi HIGURASHI

出版者

The Japan Society of Mechanical Engineers

雑誌

Mechanical Engineering Journal (ISSN:21879745)

巻号頁・発行日

vol.7, no.3, pp.19-00489, 2020 (Released:2020-06-15)

参考文献数

17

被引用文献数

5

---

The authors are developing the design concept of the pool-type sodium-cooled fast reactor (SFR) that addresses Japan’s specific siting conditions such as earthquakes and meets safety design criteria (SDC) and safety design guidelines (SDG) for Generation IV SFRs. The development of this concept will broaden not only options for reactor types in Japan but also the range and depth of international cooperation. A design concept of 1,500 MWt (650 MWe) class pool-type SFR was thought up by applying design technology obtained from the design of advanced loop-type SFR, named JSFR, equipped with safety measures that reflect results from the feasibility study on commercialized fast reactor cycle systems and fast reactor cycle technology development, improved maintainability and repairability, and lessons learned from the Fukushima Daiichi Nuclear Power Plants accident. The design concepts of a reactor vessel (RV) and its internal structures have been investigated whether they could withstand severe seismic conditions in Japan and thermal loads. The design adopted enhanced RV support structure, enhanced conical-shaped core support structure, a thickened knuckle part of the RV, and a flat plenum separator with ribs. A three-dimensional steady-state thermal hydraulic analysis of the RV revealed that the temperature difference of the upper and lower surfaces of the flat plenum separator could be effectively reduced by installing layers of thermal insulation plates. The authors have also conducted a transient analysis of loss of flow type anticipated transients without scram events to evaluate the feasibility of a self-actuated shutdown system. Moreover, the configuration of the decay heat removal system has been investigated considering sufficient utilization of natural circulation capability of sodium coolant, heat removal capacity of each cooling system, conformance with design requirements, and recommendations of SDC and SDG such as diversity and redundancy of components.

著者

Masateru MAEDA Hao LIU

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.8, no.4, pp.344-355, 2013 (Released:2013-12-24)

参考文献数

15

被引用文献数

10 22

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In very few studies it is shown that an increase in vertical force can be achieved when a flapping-wing hovers in ground effect (IGE). The body, however, has usually been neglected and its influence on three-dimensional vortex structures and consequent aerodynamic forces is still unclear. In this study we carried out a computational fluid dynamic study of a fruit fly (Drosophila melanogaster) hovering for two cases: “in ground effect” and “out of ground effect” (OGE), where the heights from the ground are less than one and more than five times the wing length, respectively. The wings in the IGE computation generated merely 0.7% larger wingbeat cycle-averaged vertical force than in the OGE condition. The body, in contrast, exhibited a significant increase in the vertical force: when out of ground effect, the average vertical force of the body was almost zero (-0.0025 μN); whereas in ground effect, the force increased to 0.78 μN, which is the major contributor to the 8.5% increase in the total vertical force (from 9.9 μN at OGE to 10.8 μN at IGE). Meanwhile, the aerodynamic power of the wings decreased by 1.6%, resulting in a 10% improvement in the overall vertical force-to-aerodynamic power ratio. The flow-field visualization revealed that the downwashes generated by the wings create a high pressure “air cushion” underneath the body, which should be responsible for the enhancement of the body vertical force production. Our results point to the importance of the presence of body in predicting the vertical forces in flapping flights in ground effect.

著者

Shohei TAKAOKA Tsutomu KAIZUKA Bo YANG Kimihiko NAKANO

出版者

The Japan Society of Mechanical Engineers

雑誌

Mechanical Engineering Journal (ISSN:21879745)

巻号頁・発行日

vol.7, no.2, pp.19-00572, 2020 (Released:2020-04-15)

参考文献数

28

被引用文献数

1

---

Methods for presenting information by utilizing a visual field (such as driver peripheral vision) are attracting increased attention in association with an increase in the amount of information required for driver assistance. However, studies on interfaces utilizing such a visual field are currently insufficient. In addition, to avoid information overload, it is important to evaluate different interfaces in terms of the amount of information presented. The authors researched those interfaces from the viewpoint of ergonomics with the purpose that the result is possible to be applied to various researches mainly in the field of automobiles. Through an in-house experiment, participants viewed video clips presenting dot patterns within their peripheral vision or effective visual field (which is nearer to the gazing point than peripheral vision), and then answered questions regarding the positions and moving directions of the dots and the mental workload they experienced. The authors prepared two types of dotted patterns (fixed and moving) based on the perceptive characteristics of peripheral vision. The number of dots varied from one to six. The rate of misperception and participant mental workload were calculated. The results showed a tendency for the effect of the visual fields to depend on the type of dot pattern. It appears that the interface for peripheral vision may have resulted in a lower accuracy when fixed objects were presented, whereas fewer differences occurred when moving dots were shown. This implies that information with motion can be more suitable for interfaces utilizing peripheral vision. A larger amount of information and number of tasks resulted in lower accuracy and higher workload. Moreover, the relation between the number of dots and the rate of misperception (estimated based on percentage) suggests that the rate of misperception may increase significantly when either four or more fixed objects, or three or more moving objects, are presented.

著者

Kota TOMIUKA Yu NISHIO Seiichiro IZAWA Yu FUKUNISHI

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Fluid Science and Technology (ISSN:18805558)

巻号頁・発行日

vol.15, no.1, pp.JFST0001, 2020 (Released:2020-01-01)

参考文献数

23

被引用文献数

1

---

In this study, the receptivity of a flat-plate boundary layer was studied by introducing a thin sheet-type disturbance. An airfoil-shaped device was used to generate a thin disturbance without velocity deficit in which a steady jet was ejected from its trailing edge to the downstream. Despite the absence of strong disturbances in the freestream outside the boundary layer, streaky structures similar to an ordinary bypass transition were generated. They meandered slowly in the spanwise direction where their downstream parts were oscillating in a delayed fashion. Turbulent spots were formed in the further downstream region. Consequently, the energy growth of the low frequency band in the velocity fluctuation spectrum was found to originate from this meandering motion of the streaks, whereas the growth of the middle- and high-frequency bands was attributed to the appearances of the turbulent spots.

著者

Kohei OZAWA Toru SHIMADA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Fluid Science and Technology (ISSN:18805558)

巻号頁・発行日

vol.13, no.4, pp.JFST0031, 2018 (Released:2018-11-09)

参考文献数

31

被引用文献数

7

---

The characteristics of several O/F control methods for hybrid rocket propulsion have been discussed and theoretically analyzed from the physical properties of propellants and fuel regression behavior. In this research, comparisons have been made among different oxidizer injection methods of Altering-intensity Swirling Oxidizer Flow Type (A-SOFT), Aft-chamber Oxidizer Injection Method (AOIM), and Swirling-AOIM for the throttle range with a constant O/F, design restrictions of the fuel grain, penalties on the adoption of the methods, and suitable scales of the engine. Theoretical analysis on regression rates has revealed that A-SOFT has upper and lower limits of throttle while maintaining a constant O/F whereas AOIM does not have any lower limit, and Swirling-AOIM covers both the throttle ranges. The designing restriction of the fuel grain derived from the regression rate behavior has indicated that A-SOFT using paraffin and oxygen has a potential to maintain 50-100% throttle range over a burn. The penalties for the adoption of these O/F control methods have also been discussed from the aspects of the increase in the complexity of the system, structural mass, and pressure drop at the injector for the methods using gaseous injection. The pressure drop has quantitatively been evaluated by relating the available swirl strength with the cross-sectional area and gaseous oxidizer mass flux at the injector. This analysis has revealed 5 times difference in the available swirl strength between the gaseous oxygen and the decomposed gas of 90% hydrogen peroxide. The sizing of the 1st stage of the satellite launcher has revealed that A-SOFT and Swirling-AOIM are suitable for small-scale engines with a propellant mass of 100-102 [ton] using paraffin and liquid oxygen whereas AOIM and Swirling-AOIM are suitable for engines with paraffin and 90% hydrogen peroxide.

著者

Tomohiro HIRANO Mitsuo YOSHIMURA Koji SHIMOYAMA Atsuki KOMIYA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Fluid Science and Technology (ISSN:18805558)

巻号頁・発行日

vol.14, no.2, pp.JFST0011, 2019 (Released:2019-11-07)

参考文献数

21

被引用文献数

3

---

This study proposes a shape optimization approach for the cross-sectional shape of the inner pipe of a counterflow concentric tube heat exchanger. The cross-sectional shape of the inner pipe is expressed by an algebraic expression with a small number of parameters, and their heat transfer performance is evaluated by a commercial Computational Fluid Dynamics (CFD) solver. The optimization is conducted by the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) assisted by the Kriging surrogate model, and the NSGA-II finds the optimal cross-sectional shape with many protrusions around the perimeter of the inner channel to improve the heat transfer performance. In this study, heat transfer performance is evaluated from the temperature drop at the outlet of the high-temperature fluid. The present optimization finds the optimal channel with many protrusions, which achieves lower outlet temperature than a circular channel even with the same heat transfer surface area. This result indicates that the number of protrusions plays important roles which contribute not only to increase heat transfer area but also to improve heat transfer performance.

著者

Hirochika INOUE

出版者

The Japan Society of Mechanical Engineers

雑誌

Bulletin of JSME (ISSN:00213764)

巻号頁・発行日

vol.14, no.69, pp.199-207, 1971 (Released:2008-02-15)

参考文献数

7

被引用文献数

18 43

---

Computer control of an artificial hand which is incorporated with the tactile sense and force reflection is studied. In this experimental system, a digital computer is linked to the analog-type position-servomechanisms of the artificial hand using D/A and A/D converters, so that the position references can be changed repeatedly in the direction of decreasing the measured error signals. To deal with the versatility of the operation, the software system consists of a supervisory program and many basic program modules which correspond to respective basic manipulations. Furthermore, a symbolic command language which is adequate for such a purpose is prepared. It has been shown that the greatest difficulties in carrying out the complex and dexterous manipulations such as inserting a pin into a hole, turning a crank, etc., are solved by introducing the concept of bilateral servomechanism into the programming of the control computer.

著者

Takayuki YAMADA Shinji NISHIWAKI Kazuhiro IZUI Masataka YOSHIMURA Akihiro TAKEZAWA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Environment and Engineering (ISSN:1880988X)

巻号頁・発行日

vol.6, no.3, pp.567-578, 2011 (Released:2011-04-15)

参考文献数

18

被引用文献数

2 4

---

Topology optimization has been successfully used in many industries, especially those engaged in the design and manufacturing of mechanical devices, but numerical problems are often encountered, such as grayscale representations of obtained composites. A type of structural optimization method using the level set theory for boundary expressions has been proposed, in which the outlines of target structures are implicitly represented using the level set function, and optimal configurations are obtained by updating this function based on the shape sensitivities. Level set-based methods typically have a drawback, however, in that topological changes that increase the number of holes in the material domain are not allowed. To overcome the above numerical and topological problems, this paper proposes a new topology optimization method incorporating level set boundary expressions based on the concept of the phase field method, which we apply to a minimum mean compliance problem. First, a structural optimization problem is formulated based on a boundary expression, using the level set function. Next, a time evolutionary equation for updating the level set function is formulated based on the concept of the phase field method, and the minimum mean compliance problem is formulated using a level set boundary expression. An optimization algorithm for the topology optimization incorporating the level set boundary expression based on the concept of the phase field method is then derived. Several examples are provided to confirm the usefulness of the proposed structural topology optimization method.

著者

Kazuki KIMURA Kenichiro NONAKA Kazuma SEKIGUCHI

出版者

The Japan Society of Mechanical Engineers

雑誌

Mechanical Engineering Journal (ISSN:21879745)

巻号頁・発行日

vol.2, no.3, pp.14-00568, 2015 (Released:2015-06-15)

参考文献数

22

被引用文献数

3 4

---

This paper focuses on a real-time obstacle avoidance control method for vehicles using model predictive control (MPC). MPC can optimize the motion of the vehicle over a finite time horizon while satisfying various constraints such as vehicle dynamics, the road width and the steering range. However, the computational cost is too large for conducting real-time control. In this paper, a collision avoidance is realized by MPC with constraints for avoiding prohibited regions represented as circles. We approximate this region into a half plane separated by the tangent of the prohibited region. By handling approximated regions as constraints of the road width of MPC, we can implement the collision avoidance algorithm into the controller without increasing the computational cost. Moreover, in order to reduce the computational effort, we transform the nonlinear vehicle dynamics into reduced order and linearizable subsystems called time-state control form (TSCF). The effectiveness of the proposed method is proved by comparative simulations with conventional method where artificial potential method is applied to MPC. In addition, we conduct two experiments using a 1/10 scale vehicle which is equipped with a laser range finder to execute obstacle detection and localization. We show that real-time control can be realized even if we use an on-board embedded CPU which runs at the frequency of 500MHz.

著者

Kenichi NANBU

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Computational Science and Technology (ISSN:18816894)

巻号頁・発行日

vol.6, no.3, pp.147-156, 2012 (Released:2012-09-26)

参考文献数

15

被引用文献数

1 1

---

New solution algorithms of finite-difference systems for 1D and 2D Poisson's equations were obtained by modifying Gaussian elimination. Introduction of a new naming of row and column for coefficient matrices of the systems made it possible to derive the elimination algorithms explicitly. Since the finite-difference systems for Poisson's equations are diagonally dominant, solutions with high accuracy can be obtained with no use of pivoting in the present algorithm. The computer execution time for the present algorithm would appear to be one order smaller than the time for SOR with Chebyshev acceleration.

著者

田中 裕久 大石 保徳

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.65, no.637, pp.3804-3810, 1999

被引用文献数

1

---

A double cavity half toroidal contimlously variable power transmission transmits input torque through a pair of variable units and changes its speed ratio by controlling attitude angels of four power rollers. One power roller among them is controlled by a hydraulic servomechanism and the others are followed it under the control principle of equal force transmission. Synchronization of four power rollers is guaranteed by safety wires, however nonlinearities of friction force on the control pistons or pressure delay in hydraulic lines due to air mix or pipe length cause instability of the speed ratio servomechanism through the safety wires. This paper focuses the relation between the synchronization and stability of the CVT by making bond graph analyses and experiments, and shows design guidelines on the stabilization of the double cavity half toroidal CVT.

著者

Osamu NISHIMURA

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME International Journal Series A Solid Mechanics and Material Engineering (ISSN:13447912)

巻号頁・発行日

vol.47, no.4, pp.527-532, 2004 (Released:2005-04-15)

参考文献数

5

被引用文献数

2 4

---

This paper presents the characteristics of Social Common Capital (SCC) and its role in the society of abundance. Also, it is explained why bamboo is regarded as the symbol of SCC. The society of abundance has three main characteristics. First, it should rest on the foundation of Institutionalism. Moreover, sustainable development without destruction of natural and cultural environments is required. Finally, the society of abundance should not only provide material richness, but also bring about the acceptance of ethical norms and affection toward natural and cultural environments. SCC is the social equipment sustaining the society of abundance. It can be said that bamboo might serve as an excellent example to exemplify how our society might attain sustainability and affluence, because bamboo is widely used for various ends such as the production of furniture or construction materials. Furthermore, bamboo is also important in relation to the formation of Japanese arts and literature.

著者

Hideyoshi YANAGISAWA Chihiro MIYAZAKI

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Advanced Mechanical Design, Systems, and Manufacturing (ISSN:18813054)

巻号頁・発行日

vol.13, no.1, pp.JAMDSM0013, 2019 (Released:2019-02-18)

参考文献数

26

被引用文献数

3

---

The study proposes a methodology for extracting and applying expectation effect in multisensory user-product interaction to balance the design attributes that satisfy must-be and attractive qualities in the Kano model. Satisfying both qualities is assumed to be an objective of product design. This study modeled users' cognitive process of cyclic user-product interactions. Using the model, the proposed method extracts users' cognitive structure and state transitions while interacting with a product. The cognitive structure reveals the design attributes affecting must-be and attractive qualities as well as prior cue of the expectations of these qualities. Tolerance for design attributes to satisfy both qualities and the expectation effect of prior factors are discussed. The methodology is validated using a hair dryer as a case product. Another case product (camera) demonstrates how cognitive cues work as well as sensory cues as expectation effect. The proposed methodology supports designers and researchers in structuring multisensory user-product interactions as a series of state transitions of users' cognitive model. The structure helps to extract product attributes that affect both attractive and must-be perceived qualities and attributes involving expectation effect on product qualities. The method of experiment 1 can be applied to assess tolerance for product attributes to satisfy perceived qualities. The method of experiment 2 can be applied to assess the effect of prior expectation induced by both sensory and cognitive attributes, such as a product class, on perceived quality.

著者

MORIMURA Tsutomu

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Mechanical Systems for Transportation and Logistics (ISSN:18821782)

巻号頁・発行日

vol.6, no.2, pp.90-99, 2013

被引用文献数

1

---

Research and development (R&D) has helped to maintain the high safety and service standards of the Tokaido Shinkansen since it first started operations almost 50 years ago. Recent R&D has involved large-scale field data collection and work by the Komaki Research Center. This paper discusses some examples of R&D innovations for the Tokaido Shinkansen, which reflect the developments in R&D approaches over time. One example is earthquake countermeasures, focusing on the derailment and deviation countermeasures for the Tokaido Shinkansen. Anti-derailing guard rails and post-derailment stoppers were developed and various experiments were conducted in order to not only confirm the efficacy of the earthquake countermeasures but also elucidate derailment mechanisms. The other example is condition monitoring systems. The bogie vibration detection system, which is one example of a condition monitoring system, is developed and installed on the Series N700A trainsets to monitor all bogies' conditions. These achievements of R&D further enhanced safe and reliable transportation of the Tokaido Shinkansen.

著者

遠藤 剛

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.58, no.550, pp.2003-2009, 1992

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This paper reports on flows around two-dimensional elliptic wings which are linearly arranged above a flat plate. To solve two-dimensional time-dependent incompressible Navier-Stokes equations which use a body-fitted curvilinear coordinate system, a numerical solution method has been developed, and the method has been applied to the flows around 25% thickness elliptic wing cascades slanted at an angle of attack 15°at a Reynolds number of 1.6×10<SUP>3</SUP>. Those wings are linearly arranged at an equal distance above a flat plate. This paper presents a number of numerical solutions for streamlines, vorticity profiles, lift, drag and pressure distributions. The lift and the drag almost regularly fluctuate with time, and the flow rates through each passage also regularly fluctuate. The present studies have been conducted as basic research into the mechanism of blowing snow off a road.

著者

Toru HAMASAKI Takahiro YAMAGUCHI Masami IWAMOTO

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

pp.17-00575, (Released:2018-01-18)

参考文献数

30

被引用文献数

15

---

It is difficult to experimentally observe the influence of differences in individual skin properties of human fingers on tactile perceptions. During subjective experiments, many parameters, such as skin properties, the transmittance of nerve signals, and individual feelings are intricately mixed; therefore, it is difficult to identify which elements are affected and to what extent. It has not been determined how age-related changes in the stiffness of skin influence tactile perceptions. We developed a two-dimensional cross-section human fingertip finite element model based on previous studies. Then, we estimated the influence of age-related changes in skin stiffness on Merkel cells and tactile perceptions by using finite element analysis. Age-related changes in skin stiffness were described by changing skin material properties in the model. Simulations using a model involving the fingertip being contacted with a rigid flat plate or a 2-point indenter were performed. Using a rigid flat plate and standard skin material properties, the contact width between the finger pad and the object was 5 mm. Meanwhile, the width changed from 5 mm to 4 mm when using a model of age-related changes of skin. Using a rigid 2-point indenter, the difference in the peak-to-valley of the Mises distribution around the Merkel cells indicated 2-point discrimination. Besides, the difference decreased by approximately 43% with changes in skin stiffness. These results indicated that age-related changes in skin stiffness influenced tactile perceptions.

著者

中山 信行 川本 広行

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.70, no.691, pp.804-811, 2004

被引用文献数

9

---

Formation of magnetic bead chains in a magnetic field was numerically simulated with the Distinct Element Method in order to apply for improvements of a magnetic brush development system in electrophotography. Simulated chain configurations, length and slant angle. and dynamic chain forming process were compared to the experimental results. The 2-D calculation could not simulate quantitatively well the chain configurations and the process, because the magnetic interaction between beads was under estimated due to the neglect of the interaction force between three-dimensionally distributed beads. On the other hand, 3-D calculation showed good agreement with experiments and it is concluded that 3-D calculation is indispensable for the quantitative evaluation. It was also confirmed that chain configurations were determined approximately to minimize its total potential energy given by the sum of magnetic energy and gravitational energy.

著者

戸嶋 正美 岡村 共由 佐藤 譲之良 宇佐美 賢一 田辺 誠一

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.57, no.539, pp.2186-2191, 1991

被引用文献数

2

---

Damage due to the coupled action of silts abrasion and cavitation erosion was experimentally studied using water channel in which artificial silt (Al<SUB>2</SUB>O<SUB>3</SUB>) were included. It was confirmed that the incipient cavitation number in silt laden water increased by 10-15% compared with that in tap water. It was shown that the magnitude of impact pressure measured by the pressure detecting films and casing vibration-acceleration had good correlation with the cavitation erosion intensity but not with the abrasive wear intensity. The damage patterns on aluminum specimens were greatly affected by the cavitation occurrence, but the amount of damaged volume was almost constant with and without cavitation. A ploughing type of abrasive wear was mainly observed on the damaged surface by scanning electron microscope.

著者

Hisayoshi NAKA Hiromu HASHIMOTO

出版者

The Japan Society of Mechanical Engineers

雑誌

Mechanical Engineering Journal (ISSN:21879745)

巻号頁・発行日

vol.2, no.1, pp.14-00262-14-00262, 2015 (Released:2015-02-15)

参考文献数

14

被引用文献数

5 5

---

The dragonfly wing is passively deformed under flapping and has the strength to withstand high flapping frequency simultaneously. These characteristics of deformation and vibration of the wing are important for flapping flight. However, the effect of these characteristics on flapping flight has not been well understood. The purpose of this study is to investigate deformation and vibration characteristics of the dragonfly wing, and then to develop an artificial wing suitable for flapping flight on the basis of the dragonfly wing. In this study, natural frequency and deformation of the dragonfly wing are measured, and the artificial wing is fabricated on the basis of the results. From the measured results, the dragonfly wing has the high natural frequency of about 120 Hz, and thereby, it does not resonate with flapping. Although base-side of the wing is hardly deformed, the tip-side of the wing is greatly deformed because of the torsional deformation from the nodus of dragonfly wing. On the basis of characteristics of the dragonfly wing, the deformable artificial wing that can deform in the same manner of dragonfly wings was fabricated. Then, aerodynamic force and power consumption under flapping when using the deformable artificial wing was measured. As a result, the power efficiency of aerodynamic force using the deformable artificial wing is five times greater than the power efficiency using a non-deformable wing.