著者

竹村 文男 矢部 彰

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.63, no.613, pp.2909-2914, 1997-09-25 (Released:2008-03-28)

参考文献数

10

被引用文献数

1 2

---

Drag coefficients of a spherical rising gas bubble were estimated experimentally and numerically. We developed an experimental apparatus in which a CCD camera with a microscope follows the rising bubble and used it to precisely estimate the drag coefficients of the bubble below Reynolds number of 100 by measurement of the bubble size and the terminal velocity. We also estimated numerically drag coefficients of a gas bubble in an infinite liquid by directly solving a Navier-Stokes equation. The experimental results agree well with the numerical results. Moreover, we compared the experimental results with several proposed equations for estimating drag coefficients and determined the region of applicability of each equation. Finally, we proposed an equation for estimation of drag coefficient by correlating with experimental results.

著者

大野 巧真 豊田 希 藪田 哲郎

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 2012 (ISSN:24243124)

巻号頁・発行日

pp._2A1-B10_1-_2A1-B10_2, 2012-05-27 (Released:2017-06-19)

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It is difficult to obtain stable motion arm movement only using a feedback controller because this method must use high gain feedback to achieve accurate motion in early stage of learning. Therefore, motion learning mechanism of human being's arm is explained by both feed-forward controller using internal-error learning method and visco-elasticity adaptation mechanism. This study applies this assumption to both muscle potential and its frequency characteristics show possible verification of visco-elasticity adaptation mechanism.

著者

幸坂 博史 吉川 雅博 田中 秀幸 松本 吉央 溝口 博

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 2013 (ISSN:24243124)

巻号頁・発行日

pp._1A2-K07_1-_1A2-K07_3, 2013-05-22 (Released:2017-06-19)

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In order to develop useful assistive devices, it is necessary to analyze and understand the function of human. In this study, the activities of daily living were recorded and the performance of dominant and non-dominant hand was classified according to ICF (International Classification of Functioning, Disability and Health) approved by WHO. As a result, it was revealed that the use of both hands makes a great difference. It will be reasonable to design assistive devices such as prosthetic hands for non-dominant hand to have less function (degree of freedoms, payloads etc.) than assistive devices for dominance hand.

著者

中 尚義 橋本 巨

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.82, no.833, pp.15-00209-15-00209, 2016 (Released:2016-01-25)

参考文献数

11

被引用文献数

1 1

---

Dragonflies can perform both of gliding and flapping flight and have high maneuverability in spite of small-size. The aim of this study is to develop Micro Air Vehicle (MAV) based on the flight of dragonfly. The characteristics of wings are very important for development of MAV. Dragonfly wing is easy to be passively deformed in the tip side from the nodus in flapping flight, and thereby, aerodynamic force is generated effectively. In this study, the effect of passive deformation of wing on aerodynamic force was investigated using fluid-structure interaction analysis to develop the artificial wing suitable for dragonfly-like MAV. In this study, aerodynamic characteristics of wings in the gliding flight and aerodynamic force generated in flapping flight are numerically analyzed. In this analysis, nodus wing models, which can deform passively, and rigid wing model, which cannot deform, are used. Nodus wing model imitates the nodus structure; the tip side of this model is free to rotate around leading edge. As a result of gliding flight, the lift coefficient of the nodus wing was lower in low-angle of attack and was higher in high-angle of attack, compared to rigid wing. Moreover, the more flexible wings are, the more change. The gliding flight is low-angle of attack usually. Therefore, flexible wing is less suitable for the gliding flight than inflexible wing. As a result of flapping flight, the nodus wing made drag force generated during down stroke lower compared with the rigid wing. However, thrust forces generated during up stroke in both wings were the same. Therefore, flexible wing is more suitable for the flapping flight than inflexible wing. The wings of dragonfly-like MAV need to appropriate level of flexibility to upgrade the performance in both case of gliding and flapping flight.

著者

橋本 巨 石本 早霧

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.63, no.607, pp.723-731, 1997-03-25 (Released:2008-02-26)

参考文献数

20

被引用文献数

1 1

---

Elucidation of the vibration mechanism of winged insect from the viewpoint of bionic design might aid in development and design of the driving systems for small- or micro-size actuators, because some flying insects easily overcome scale effects through use of wing vibration and achieve flight with high robustness and speed under conditions of large air viscosity. The aim of this report is to describe a theoretical model of the dynamics of relatively large-size insect wings powered by the direct-flight-muscle and of the dynamics of small-size insect wings powered by the indirect-flight-muscle. Based on morphological consideration of these two types of insect wing dynamics, the equations of motion for the wings are formulated. In the model, the dry friction-type and van der Pol-type forces are employed to power the wings of direct-flight-muscle-type insects, and the periodic impulsive force is assumed to power the wings of indirect-flight-muscle-type insects. Applying the equations of motion to the wings of insects such as dragonflies and flies, the wing vibration is analyzed under various conditions. From the numerical results, the vibration mechanism of two types of flying insects' wings is clarified.

著者

竹内 正顯

出版者

一般社団法人 日本機械学会

雑誌

年次大会講演資料集 2005.8 (ISSN:24331333)

巻号頁・発行日

pp.112, 2005-09-18 (Released:2017-08-01)

著者

和泉 遊以 田邉 裕貴 阪上 隆英

出版者

一般社団法人 日本機械学会

雑誌

産業・化学機械と安全部門講演会講演論文集 2016.冬 (ISSN:24243159)

巻号頁・発行日

pp.OS-5, 2016 (Released:2017-06-19)

著者

野中 朋美 清水 香那 水山 元

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.82, no.842, pp.16-00166-16-00166, 2016 (Released:2016-10-25)

参考文献数

12

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This paper proposes a dynamic table assignment method for a restaurant to reduce customer waiting time and inequality of lengths of waiting among customers. It develops a simulation model to estimate the remaining time until departure of each customer and evaluates effective sequences of table assignment in terms of waiting times and availability of tables using the model virtually. Gini coefficient value is used as an evaluation index for measuring inequality. In this paper, two conventional table assignment rules and the proposed method are described. Computer experiments demonstrate that the proposed method is superior to the conventional rules which assign in First In First Out (FIFO) way or assign smaller customer groups before larger ones.

著者

植木 洋輔

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.81, no.821, pp.14-00225, 2015 (Released:2015-01-25)

参考文献数

7

被引用文献数

1

---

The objective of this study is to establish a methodology for high-speed fatigue testing, especially for resin materials, which includes fiber reinforced composites. To exert periodic stress on a material at a frequency of more than 200 Hz, a specimen was fixed as a cantilever to an electromagnetic vibrator and vibrated in its resonant frequency of the 1st bending mode by using a resonance tracking control. The shape of a specimen made of glass fiber-epoxy laminate was designed with finite element vibration analysis to obtain a resonant frequency of more than 200 Hz and a desired strain distribution for inducing fatigue damage under a certain stress level. A rise of temperature during the fatigue testing due to damping loss was estimated with a heat transfer theory and suppressed by external cooling to keep the specimen at a normal temperature. To confirm the validity of the high-speed testing, a completely reversed bending test at 1 Hz with identical specimens was also performed. Results both from testing at 230 Hz and 1 Hz were plotted on a single power-law curve in an S-N plot, which is a well-known fitting for fiber reinforced composites. This result suggests that we can evaluate fatigue strength in the high- or giga-cycle region for resin and composites in a very short time if temperature is controlled appropriately.

著者

山口 哲郎 仙波 卓弥

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.73, no.732, pp.2394-2400, 2007-08-25 (Released:2011-03-04)

参考文献数

10

被引用文献数

2 2

---

A high-speed microfabrication technique using a focused laser beam was developed. A conventional CAD/CAM system was used, and the beam was scanned mechanically by attaching both optical mirror arrays and a focal lens to the column of an ultraprecision machining center. The measured groove width and pocket depth obtained by grooving and pocket machining were used as the tool diameter and the axial depth of cut, respectively. Glasslike carbon with a laser beam absorptivity of over 80% and a hardness of 650 MHv was employed as a workpiece. It was verified through a machining test that pseudo-3-dimensional concave prisms can be fabricated by digging square pockets with different square sizes but the same pocket depth in the negative Z direction. Shifting the laser's focal point away from the work surface can decrease the depth of the square pocket, so that high-speed roughing by adjusting the focal point on to the work surface and highspeed finishing by shifting the focal point away from the work surface can be conducted.

著者

富岡 隆弘 瀧上 唯夫

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.70, no.696, pp.2419-2426, 2004-08-25 (Released:2011-03-04)

参考文献数

15

被引用文献数

3 11

---

This paper presents a method to suppress the vertical bending vibration of railway vehicle carbody by using carbody-truck (or bogie) interaction. It is shown from the running test result of an actual Shinkansen vehicle that the bending vibration can greatly be reduced when the rigidity of carbody-truck connecting elements in the longitudinal direction (i.e., rubber bush rigidity of traction links and anti-yaw dampers) Kx is set at the optimum value. The mechanism of the effect to reduce such vibration is analyzed theoretically. As a result, it is found that the truck frames and wheelsets act as dynamic vibration absorbers against the bending vibration of carbody. A formula to adjust Kx to its suitable value is derived. The accuracy and validity of the formula is evaluated numerically.

著者

中島 賢治 戸田 尊 山本 隼年 川崎 隆之

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会誌

巻号頁・発行日

vol.119, no.1172, pp.402-403, 2016

著者

片桐 拓也 佐々木 幸太 遊佐 訓孝 橋爪 秀利

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

巻号頁・発行日

vol.84, no.859, pp.17-00375-17-00375, 2018

被引用文献数

5

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<p>This study proposes nondestructive long-range inspection for axial cracks appearing at the inner surface of a metal pipe using microwave. Numerical simulations were conducted to design a mode converter that converts TEM into TE mode that is necessary to detect axial cracks. The simulations confirmed that situating coaxial cables circumferentially enables to propagate microwaves in TE mode inside a pipe. The results also revealed that the number and positions of coaxial cables affect the frequency range where microwaves propagate as TE₀₁ mode dominantly. A mode converter with four coaxial cables was fabricated according to the results of the simulations aiming at the propagation of microwaves as TE₀₁ mode. Experimental verification was conducted using a brass pipe with a total length of 11.6 m and an inner diameter of 19.0 mm, and having the mode converter at the center. The results showed significant difference between the signals with and without an artificial slit simulating a crack. This study also proposed a signal processing method to compensate for the dispersion of microwaves with an aid of a window function. The signal processing method gave the clearer signals corresponding to the slits to determine the predict position of the slit quantitatively using the time-of-flight of the signals.</p>

著者

五福 明夫 単 万里 柴田 光宣 山西 輝裕 亀川 哲志

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.77, no.778, pp.2400-2406, 2011 (Released:2011-06-25)

参考文献数

13

被引用文献数

2

---

This study develops a mixing machine driven by a spherical motor that can rotate around any axis. The developed mixing machine is composed of a rotor, a stator, a control PC, an electro-magnet excitation circuit, and a power supply. The rotor that its outer diameter is 200 [mm] is composed of double spherical shells in order to contain liquid in its inner spherical shell. Totally 91 permanent magnets are arranged in almost spherical symmetry on the inner surface of the outer spherical shell. On the other hand, 80 electro-magnets are arranged on the stator of a semi-spherical shell. The applicability of the mixing machine to material production under the condition of small influence of gravitational force is evaluated by mixing experiments to dissolve salt of 50 [g] in water of 200 [g]. The mixing performance is compared for five mixing methods. The results show that the mixing performance of the method to change randomly the rotation direction is only slightly lower than that of the method of rotating continuously around a horizontal axis that exhibits the highest mixing performance.

著者

井上 裕嗣 岸本 喜久雄 中西 智明 渋谷 壽一

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 A編 (ISSN:03875008)

巻号頁・発行日

vol.61, no.581, pp.153-160, 1995-01-25 (Released:2008-02-21)

参考文献数

17

被引用文献数

5 6

---

The wavelet transform is applied to time-frequency analysis of dispersive stress waves. The Gabor function is adopted as the analyzing wavelet. The magnitude of the wavelet transform of wave data takes its maximum value at the time when the stress wave reaches the observation point with its group velocity at each frequency. An experiment on the flexural wave in a beam shows that the dispersion relation for the group velocity can be accurately identified by the wavelet transform of measured data. In addition, the application of the wavelet transform to ultrasonic testing of a polymer alloy shows that changes in velocity and attenuation coefficient due to mechanical damaging can be evaluated at each frequency. These results suggests that the wavelet transform has potential ability to present more detailed evaluation of material damages.

著者

河原崎 徳之 阿妻 峻 吉留 忠史

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.2A2-M01, 2017 (Released:2017-11-25)

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This paper provides a supernumerary robot arm which is attached to the person's waist. This robot arm what we call the third arm. The robot arm is composed of four parts which are an upper-arm, fore-arm, hand and an attachment. The size of the arm is same as the person of it. The robot arm has six degrees of freedom of motion and each joints moves by the servo motor. We conducted several experiments in order to clarify the effectiveness of our robot arm.

著者

南大路 謙一

出版者

一般社団法人 日本機械学会

雑誌

機械學會誌

巻号頁・発行日

vol.38, no.223, pp.773-776, 1935

著者

栗屋野 伸樹

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.120, no.1184, pp.15-16, 2017-07-05 (Released:2017-09-15)

著者

内田 康之 石田 直也 杉本 実夏 青木 岳史

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.1P2-O02, 2017 (Released:2017-11-25)

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When terrorism occurred at tunnel of the subway, the police and Japan Self Defense Forces have to scout in the tunnel while confirming the safety in the tunnel. It’s said that they need the robot which does such dangerous work for the unit. So we have developed the information gathering robot which can travel on the railroad track of the subway. This robot can pass easily a gap and a curve of a rail by a bogie mechanism. In this report, we describe the driving performance of this robot.

著者

原田 隆宏 鈴木 幸人 越塚 誠一 荒川 貴博 庄子 習一

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.73, no.726, pp.437-444, 2007-02-25 (Released:2011-03-03)

参考文献数

13

被引用文献数

1 3

---

In this study, we developed a code which can calculate three-dimensional micro multi-phase flow using Moving Particle Semi-implicit method. Surface tension which dominates the fluid motion in micro flow also makes the time steps very small and the simulation time becomes very long. We employed a sub-time steps algorithm that enable us stable and efficient calculation of micro fluid with strong surface tension. Using developed code, micro droplet generation in y-shaped micro channel is calculated. We could realize micro droplet generation in our calculation as the same as experiment. In our calculated results, we measured droplet size. The measured droplet size quantitatively agrees with experimental ones. We also visualize flow inside of droplet when a droplet is generated in the calculated results.