著者

大友 康平 渡邉 鉄也 鞆田 顕章

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

pp.14-00623, (Released:2015-06-12)

参考文献数

14

被引用文献数

2 2

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Lure fishing and fly-fishing have been positioned as sports deliberately different from the traditional Japanese fishing-style. In the case of fly-fishing, casting is the element which anglers must master in order to cast a fly, done so by using the weight of a line. This study uses experimental and computational analysis to investigate the dynamic behavior of a fly line. Fly-fishing is constituted by various elements, but the importance that casting holds is extremely large. Fling speed, the casting process and the loop shape of the line while in flight are important that casting holds is extremely large. Fling speed, the casting process and the loop shape of the line while in flight are important for the proper presentation of flies. Moreover, the shape of a fly line is also important for a long cast or controlled cast. Fly is a lure that imitates an aquatic insect or a small fish, and becomes the prey of the target fish. And, there are countless of fly patterns. Therefore, anglers necessary to select an appropriate rod or line according to the size of the fly. In this paper, a rod, a line and arms are modeled by using rigid bodies and links. The time history behavior of the model is calculated by pseudo angler velocity of the arms. The validity of the model in detail is investigated. And, proper rod and line in accordance with the fly of the size is verified.

著者

中野 幸人 富田 直 瀬木 真琴 西村 拓也

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.88, no.911, pp.21-00395, 2022 (Released:2022-07-25)

参考文献数

24

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Electric vehicles (EVs) generate different cabin noise from internal combustion engine vehicles (ICE) during low-speed driving. In order to identify the cause of the interior noise of EVs at low-speed (30km/h) and to reduce the noise, a Helmholtz resonator made of pulp molds was fabricated and its noise reduction effect was evaluated. First, a Helmholtz resonator to reduce the cavity resonance of the tire is investigated by numerical calculation. Through numerical calculations, it was demonstrated that a stable noise reduction effect could be achieved by installing multiple Helmholtz resonators. Next, we fabricated a Helmholtz resonator using pulp molds as the material and installed multiple resonators in the tire. In the experiment, the resonators were able to reduce the tire cavity resonance by 13.8 dB to 9.7 dB. When driving tests were conducted with these tires installed, the noise at the ear position of the front seats in the cabin was reduced by 11.3 dB. From these results, we were able to identify that tire cavity resonance is the cause of the cabin noise when the EV is running at low-speeds. In addition, a driving test in which the same number of Helmholtz resonators as installed in the tires were installed on the cabin ceiling resulted in an 8.1 dB reduction in cabin noise. This demonstrated that it is possible to reduce the noise caused by tire cavity resonance even with parts inside the vehicle.

著者

岩﨑 はるな 岩瀬 英治

出版者

一般社団法人 日本機械学会

雑誌

ロボティクス・メカトロニクス講演会講演概要集 2017 (ISSN:24243124)

巻号頁・発行日

pp.1A1-K10, 2017 (Released:2017-11-25)

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We proposed switchable and holdable adhesive mechanism using a suction cup and a chamber with a check valve for skin-attaching device. For long-term use of skin-attaching electronic device, both high adhesion during wearing and low adhesion for peeling are required. The chamber induces suction pressure of the suction cup attached to skin. The check valve achieves to switchable and holdable adhesion without vacuuming during wearing by preventing backward flow. In this paper, we evaluated the adhesion force of the device using switchable adhesive mechanism and confirmed that the switchable adhesive mechanism has low and high adhesion.

著者

増田 殊大 杉松 治美 小島 淳一 西田 祐也 巻 俊宏

出版者

一般社団法人 日本機械学会

雑誌

ロボティクス・メカトロニクス講演会講演概要集 2021 (ISSN:24243124)

巻号頁・発行日

pp.1A1-B03, 2021 (Released:2021-12-25)

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Most of the conventional hydrophones (underwater microphones) use PZT ceramic as the material, and there are problems such as variation in sensitivity, the necessity of high-magnitude amplification and high cost.We developed and evaluated a low-cost, easy-to-use MEMS hydrophone that is waterproof and pressure-resistant while maintaining the bandwidth of a commercially available MEMS microphone.

著者

平田 大貴 山田 泰之 大室 健 森田 寿郎

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集C編 (ISSN:18848354)

巻号頁・発行日

vol.78, no.786, pp.547-556, 2012 (Released:2012-02-25)

参考文献数

11

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This paper proposes a new jumping unit that using chemical energy. Conventional jumping robots have difficulties to equip both lightweight and high output energy at the same time. In regard to this, chemical energy of black powder was adopted. Using explosives allows jumping robots to get high energy instantaneously. First of all, acceleration and velocity characteristics of the cylinder were clarified by experimental cylinder. The approximate expression of pressure change in the cylinder was derived based on the characteristics. Second, expressions of jumping theory were lead and relationships between some parameters (mass, rod-area, cylinder stroke) and jumping height were simulated. Curves with a peak were given from all of those parameters and existence of optimal value was clarified. The significance of the simulation was shown by jumping motion of about 2000mm by the experiment. Finally, four-legged robot dummy with jumping unit that change direction, control of height and isolated ignition were available, is developed. Trajectory of jumping motion was examined when the direction of cylinder was changed from vertical condition. Effectiveness of proposed method was confirmed from jumping height of 720mm with cylinder angle of 10 degree.

著者

清水 哲雄 小松 治男 馬田 俊雄 高橋 清 佐藤 正矩

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.64, no.623, pp.2348-2353, 1998-07-25 (Released:2008-02-26)

参考文献数

3

被引用文献数

1

---

Understanding the spinning mechanism of an impacted golfball is an important factor in golf science and engineering. The rigid sphere model which considers the Coulomb-type slip friction presented independently by Daish and Kawamura (referred to here as the Daish-Kawamura model) seems to well explain the experimental results of golfball spinning. For a more general interpretation of the spin phenomenon, we attempted to modify this model by introducing a physical quantity called the "s parameter", which is defined as the ratio of the circumferential velocity of the ball to its centroid velocity. An experiment performed to verify the appropriateness of the new parameter introduction led to the following conclusions: The spin phenomenon in golf impact can be divided into two phases, in both of which the Daish-Kawamura model is effective. A method is described to evaluate the coefficient of slip friction under high sliding velocities, and the value is estimated as 0.07 for a slippery surface condition.

著者

荒井 都子 工藤 優汰 三木 則尚

出版者

一般社団法人 日本機械学会

雑誌

マイクロ・ナノ工学シンポジウム 2015.7 (ISSN:24329495)

巻号頁・発行日

pp._28pm3-E-4, 2015-10-21 (Released:2017-06-19)

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In this paper, we propose a candle-like micro-needle electrode for electroencephalogram (EEG) measurement from the hairy part of the scalp. Conventional wet electrodes for EEG measurement require skin abrasion and electrically conductive gel. This is time-consuming and uncomfortable. On the other hand, micro-needle electrodes can eliminate this process by penetrating through the high impedance stratum corneum. So far, our group has developed a polymer-based dry micro-needle electrode and measured EEG from the frontal pole. However, it was impossible to measure EEG from the hairy part of the scalp by using this electrode because hair obstructs contact between microneedles and the scalp. Therefore, we fabricated candle-like micro-needle electrodes that has pillars for avoiding hair and measured EEG from the occipital, where there is hair. The acquired signal showed as high quality as the conventional wet electrode.

著者

伊坂 忠夫 Robert J. GREGOR 川村 貞夫

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.64, no.623, pp.2429-2436, 1998-07-25 (Released:2008-02-26)

参考文献数

20

被引用文献数

1 4

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The purpose of this study is to derive the reasonable lifting movement from analysis of biomechanical characteristics of the snatch, back lift (BL) and leg lift (LL) in a skilled weightlifter. During the snatch lift, the differences between skilled and unskilled lifter appear in EMG and joint torque patterns. The skilled lifter utilizes the double knee bend technique and motor unit recruitment patterns in agonist and antagonist about joint might be reasonable to lift heavy weight. The present data suggest that skilled weightlifter has acquired the higher neuromuscular performance, which is required the control among the recruited muscles with regard to the tension and the timing of the coactivation and the contraction-relaxation. From comparison of BL and LL, it is suggested that BL has higher EMG activity and produces a much higher shear force about L 5/Sl joint which induces a low back injury. In case of LL, the shear force about L 5-Sl joint depends on the lifting posture. Moreover, it is revealed that the skilled weightlifter might have a lower shear force than unskilled person. From the experimental results, it is shown that the detailed instruction about lifting posture is needed to reduce the incidence of low back injury.

著者

矢野 史花 小野 貴彦

出版者

一般社団法人 日本機械学会

雑誌

中国四国支部総会・講演会 講演論文集 2021.59 (ISSN:24242764)

巻号頁・発行日

pp.09c2, 2021 (Released:2021-09-25)

著者

祖山 均 田中 麻友 滝口 尚 山本 松男

出版者

一般社団法人 日本機械学会

雑誌

東北支部総会・講演会 講演論文集 2020.55 (ISSN:24242713)

巻号頁・発行日

pp.111_paper, 2020 (Released:2020-09-25)

著者

田島 貴一 矢木 啓介 森 善一

出版者

一般社団法人 日本機械学会

雑誌

ロボティクス・メカトロニクス講演会講演概要集 2021 (ISSN:24243124)

巻号頁・発行日

pp.2P3-I01, 2021 (Released:2021-12-25)

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We have developed an impulsive motion generator mimicking Alpheus brevicristatus. Alpheus brevicristatus can close their claw at the speed that generates plasma shock waves in water. We employ their unique joint structure called the cocking slip joint and design an artificial actuation mechanism with a passive elastic element to induce the impulsive motion through storing and releasing the elastic energy; rather than adopting their musculoskeletal structure as it is. Our design approach allows the developed device to generate the impulsive motion repeatedly by a single actuator with a small actuation force compared with the stored elastic energy, which is verified through experiments.

著者

高橋 易資 野村 友和 石間 経章 小保方 富夫

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.71, no.706, pp.1694-1701, 2005-06-25 (Released:2011-03-03)

参考文献数

17

被引用文献数

2 4

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A computational fluid dynamics (CFD) code with partial cells in Cartesian coordinate (PCC) method has been developed. The merit of this method is that input data preparation time is extremely short because computational mesh data are separated from geometry data. However, a general Cartesian coordinate method has a big subject in calculation accuracy. One of the factors is precision in geometry expression around the complicated shape, and another is a turbulence model near the wall because mesh is independent from the boundary and not fitted with it. Therefore, discretization equations were derived based on Finite Volumetric Method, and a combination of the wall function and a low Reynolds number k-ε turbulence model was proposed here. This paper describes implementation of this method and shows the results compared with experimental data by particle image velocimetry (PIV) at the steady flow in the cylinder of a 4-valves S.I. engine. The comparison results of velocity vector maps show good agreement between CFD and PIV.

著者

小林 康徳

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会誌 (ISSN:24242675)

巻号頁・発行日

vol.97, no.910, pp.772-774, 1994-09-05 (Released:2017-06-21)

参考文献数

3

著者

石橋 彰 園田 計二 前之園 好爾

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.62, no.594, pp.721-728, 1996-02-25 (Released:2008-02-26)

参考文献数

8

被引用文献数

2 1

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This paper derives new equations for calculating the efficiencies of differential gear drives using simple laws based on mechanics, When the new equations are used, the efficiency for speed reduction is lower than that for speed increase, in most cases. This is completely opposite to the case of the results obtained from the earlier equations. The reason for this is clearly shown by analyzing the power flows used for deriving the equations. It is found that the power flows used for deriving the earlier equations do not satisfy the boundary conditions due to an assumption which is unconsciously introduced in the process of deriving the equations. Numerical calculations are conducted and differences in the efficiencies are shown in the case of representative differential gear drives.

著者

飛田 和輝 金森 哉吏 大久保 祐人 小川 博教 杉田 澄雄

出版者

一般社団法人 日本機械学会

雑誌

ロボティクス・メカトロニクス講演会講演概要集 2011 (ISSN:24243124)

巻号頁・発行日

pp._1P1-E08_1-_1P1-E08_4, 2011-05-26 (Released:2017-06-19)

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We have proposed a new three dimensional environment recognition method using conical scanning distance measurement for 3-D mobile robot that can walk up and down the stairs. This report describes the method to recognize the stair by applying the conical scanning method. The procedures are as follows. 1) Recognizing the positions and postures of multiple regions on 3D-TOF-camera. 2) Linking neighboring regions by using image processing. 3) Extracting the step based on height information. 4) Calculating the position, direction and width of the stair. We devised the algorithm, implemented, and experiments were carried out.

著者

松平 精

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会誌 (ISSN:24242675)

巻号頁・発行日

vol.83, no.736, pp.273-278, 1980-03-05 (Released:2017-06-21)

著者

伊藤 献一 矢野 利明 永坂 玲

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.48, no.428, pp.803-810, 1982-04-28 (Released:2008-03-28)

参考文献数

18

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単筒エンジンをメタノールで運転し,排気管に沿う未燃燃料とCH2Oの変化を調べた.400℃以上で未燃メタノールは排気管中で酸化のため減少するのに対し,CH2Oは減少せず希薄運転では増加することを見い出し,両者の成因は異なることを指摘した.この原因は,CH2Oがメタノールの酸化に伴い生成されることにあり,排ガス温度が400~600℃において,CH2O濃度は増加現象を示すことを,定温度場における反応実験により裏づけた.

著者

槙 俊明 野沢 峻一 神崎 秀 岡田 慧 稲葉 雅幸

出版者

一般社団法人 日本機械学会

雑誌

ロボティクス・メカトロニクス講演会講演概要集 2008 (ISSN:24243124)

巻号頁・発行日

pp._2A1-D18_1-_2A1-D18_3, 2008-06-06 (Released:2017-06-19)

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Humanoids are expected to expand their playing field outside the laboratory. To widen their appeal, environment contaction works such as door opening, object transport are something that must be done. Researches on environment contaction motion s that have been done are often premised physical parameters about unknonw objects. However, to manipulate unknonw objects in the unknown environment, acquisition of target's physical model by humanoids will be needed. In this paper, we firstly categorize model estimations required for unknonw object operation. Then, we estimate physical model of a door offline. And using this model, we realize door opening motion by HRP2-JSK.

著者

中村 裕道

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会誌 (ISSN:24242675)

巻号頁・発行日

vol.84, no.748, pp.268-272, 1981-03-05 (Released:2017-06-21)

著者

佐藤 峻介 髙橋 正樹

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集C編 (ISSN:18848354)

巻号頁・発行日

vol.79, no.801, pp.1526-1539, 2013 (Released:2013-05-25)

参考文献数

14

被引用文献数

3 5

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Recent years, it has been required accurate and agile attitude control of satellites. For this purpose, the necessity of Control Moment Gyros (CMGs) has been increasing, which can generate much higher torque than Reaction Wheel which is used for a conventional spacecraft actuator. CMGs have singularity problem that they cannot output a desired torque. Several singularity avoidance methods have been proposed, but they can fail to output the desired torque through the mission because of their singularity avoidance action. In this paper, we focus on singularity and CMGs' angular momentum and propose a singularity avoidance method by planning path in angular momentum space. Because output torque from CMGs depends on path of angular momentum, we plan the angular momentum path that avoids singularity and its length is short as possible by application of A* algorithm. It is shown from the simulations that the proposed method can realize desired output torque and assured singularity avoidance.