著者

三浦 智 鈴木 智裕 小林 洋 藤江 正克

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.83, no.850, pp.16-00414, 2017 (Released:2017-06-25)

参考文献数

30

被引用文献数

1 2

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Hemiplegic patients often have reduced typing speed due to finger paralysis. Our motivation is to develop a keyboard that enables their typing speed to increase. For this purpose, we have developed a three-dimensional keyboard that reduces the distance that fingers move while typing. In this paper, our objective was to construct the finger model that combines the motion speed and muscle fatigue for design of keyboard that can be typed with fast motion speed and low muscle fatigue. In experiment, we measured the finger position using a magnetic 3D motion device and EMG when the participant pressed the proposed key. The experiment was carried out in a variety of the finger postures. We qualified the motion speed and muscle fatigue at each joint angle. Then, we weighted and combined two of the objective functions. We found out the Pareto solution and get an effective keyboard design straight. In the future, we verify the typing speed and finger muscle fatigue during typing the three-dimensional keyboard that is designed based on our finger model.

著者

兼重 寛九郎 西脇 仁一 家本 潔 近藤 俊雄 田島 達之輔 鍋谷 正利 松岡 秀夫 山口 照二 川田 正秋 小川 清二 渡部 寅次郎 伊藤 茂 彦坂 栄次 伊東 勇雄 松井 武夫 菱田 錦吾 島崎 喜三郎 月本 一男 土屋 健三 近藤 善一郎 戸田 康明 岡村 健二 阿知波 二郎

出版者

一般社団法人 日本機械学会

雑誌

日本機械学會論文集 (ISSN:00290270)

巻号頁・発行日

vol.15, no.52, pp.103-132, 1949 (Released:2008-03-28)

著者

堀 光平

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.782, pp.3823-3827, 2011 (Released:2011-10-25)

参考文献数

8

著者

村松 貞次郎

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:00214728)

巻号頁・発行日

vol.83, no.735, pp.144-149, 1980

被引用文献数

1

著者

神田 睦月 徳田 献一 入部 正継 森田 成昭 齊藤 安貴子 八上 修一 小堀 亮

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-C02, 2017 (Released:2017-11-25)

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In recent years, aging of agricultural workers has progressed, attention is paid to ICT conversion of agriculture and Functional food with health maintenance effect. Raspberry contains a large amount of compounds that have a high health maintenance effect, which takes time and labor for cultivation. The purpose of this research is to construct an image processing system that recognizes color and position information in order to check whether harvesting of raspberries is possible under an indoor environment. As research contents, RGB values of colors of berries at various stages were calculated from spectral analysis results of berries and compared with actual fruit photos. We also classified colors in the image using machine learning and verified its accuracy.

著者

円山 重直

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:18848346)

巻号頁・発行日

vol.78, no.796, pp.2127-2141, 2012 (Released:2012-12-25)

参考文献数

13

被引用文献数

2 4 1

---

An accident scenario of Fukushima Daiichi Nuclear Power Plant, Unit 2 is analyzed from the data open to the public. Phase equilibrium process model was introduced that the vapor and water are at saturation point in the vessels. Proposed accident scenario agrees very well with the data of the plant parameters obtained just after the accident. The estimation describes that the rupture time of the reactor pressure vessel (RPV) was at 22:50 14/3/2011. The estimation shows that the rupture time of the pressure containment vessel (RCP) was at 7:40 15/3/2011. These estimations are different from the ones by TEPCO, however; many measured evidences show good accordance with the present scenario.

著者

伊藤 史斗 長谷 和徳 内田 和男

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.19-00191, (Released:2019-09-11)

参考文献数

15

---

The frame stiffness in a racing bicycle might influence not only toughness as the frame structure but also performance of an athlete. The purpose of this study is to clarify biodynamic relations between the frame stiffness in a racing bicycle and the physical loads of an athlete by using a forward dynamics simulation model. The human body structure was represented by the 13-rigid-links and 23-degrees-of-freedom model. Based on the theory of multibody dynamics, the frame structure was expressed by combination of 12 rigid pipes, and the frame stiffness was modeled by rotational springs at the connecting joint between the rigid pipes. Spring coefficients were changed according to the thickness of the frame pipes. The pedaling load from the crank was computed by the angular velocity and angular acceleration of the crank. Moreover, the driving force in the bicycle was additionally defined to consider the influence of the frame weight on the human joint load. The human body model was driven by the joint toques to minimize the cost function consisting of the joint loads in the human body and the driving force in the bicycle, and also to keep desired angular velocity of the crank. Validity of the simulation was evaluated by comparing the joint angles and torques with the measured ones. As for the result, the larger stiffness of the frame resulted in smaller the joint loads in the human body, and optimal stiffness would be determined by the balance between the joint loads in the human body and the driving force in the bicycle.

著者

北澤 勇気 坂間 清子 菅原 佳城

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.89, no.927, pp.23-00114, 2023 (Released:2023-11-25)

参考文献数

15

---

In recent years, there has been active development of robots that play a role in people's lives. These robots require actuators that have high responsiveness and high output force in addition to being small. Furthermore, safety and contact affinity are also required for these actuators. An actuator that can balance high responsiveness, high output, and contact affinity is developed in this study. The proposed system is a hybrid system of hydraulic and pneumatic systems. Hydraulic systems are generally used in machines that require large forces, such as construction machinery, because they have high responsiveness and high output force. However, hydraulic systems have poor contact affinity. On the other hand, pneumatic systems are used in machines that come into contact with people, such as power assist suits and massage chairs, because they have high contact affinity, although their output is inferior to that of hydraulic systems. Generally, the mixing of air bubbles into hydraulic oil is a problem. However, as the pressure increases, the rigidity of the working hydraulic oil mixed with bubbles approaches that of pure working hydraulic oil. If this characteristic is appropriately modeled and controlled, bubbles mixed into the working hydraulic oil can create a cushioning effect. Firstly, the relationship between the pressure and rigidity of hydraulic oil mixed with bubbles is demonstrated in this paper. Secondly, the mechanism of the hybrid system and the prototype model are explained. Lastly, the results of performance evaluation through analysis and experiments are presented. From these results, this paper shows that the proposed system has the potential to balance high responsiveness, high output, and contact affinity.

著者

江波戸 明彦 蛭間 貴博

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:18848346)

巻号頁・発行日

vol.78, no.789, pp.979-983, 2012 (Released:2012-05-25)

参考文献数

3

被引用文献数

1 1

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This paper attempts to improve the performance of ear-plug type earphones. The transmission characteristics of the ear canal with/without earphones are different. Therefore, the sound quality of the earphone is a little poor compared with audio speaker. In addition, it is well-known that the acoustical characteristics of ear canal vary among individuals. Therefore, we are studying to predict the acoustical characteristics of ear canal with ear-plug type earphones by using transfer matrix method and are studying how to improve the transmission characteristics of the ear canal. In this paper, a method for adjusting the resonance characteristic of the ear canal with earphones to the characteristic of the ear canal of AV speakers without earphones using digital filtering technique is proposed. With this method, the improvement of the sound reproduction performance was verified on the basis of experiments.

著者

木村 成竹 泉 聡志 酒井 信介

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.73, no.734, pp.1105-1110, 2007-10-25 (Released:2011-03-02)

参考文献数

6

被引用文献数

4 4

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A spring washer is widely used as a method for preventing loosening. However, experimental results presented by Sakai and Yamamoto et al., show that the performance of a spring washer as a loosening prevention mechanism is at best equal to that of a washer-less joint, if not worse. In this paper we analyzed loosening under shear loading and as a result were able to explain the mechanism that accelerates loosening in the framework of the three-dimensional finite element method (FEM). A spring washer causes non-uniformity of contact pressure at the washer interfaces, because of its asymmetric shape. When a bolted joint with a spring washer is subjected to shear loading, sticking area on the contact surfaces of the spring washer is limited to two corner points before the bearing surface undergoes gross slip. One of these points is on the upper surface of the spring washer and the other is on the lower surface. In this situation the nut rotation around these sticking points results in drastic loosening. We also conducted comparative simulation with Sakai's experimental results. Compared with experimental results, the bolted joint with the spring washer is easy to loosen according to the simulation results. It is believed that the difference comes from the spring washer's edge cutting into the contact surface of the nut, something not included in this simulation.

著者

小柳 健一 野田 堅太郎 大島 徹 増田 寛之 塚越 拓哉 桒子 嘉美 木谷 尚美

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.89, no.927, pp.23-00128, 2023 (Released:2023-11-25)

参考文献数

26

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When mascot suits or plush fabrics are used to cover a human-friendly robot, frequent sterilization may be required, depending on the use of the robot. However, the effects of such sterilization are not sufficiently understood. In this study, variations in the strength and color values of plush fabrics were measured and quantitatively evaluated following 50 cycles of sterilization by ethylene oxide gas (EOG). The fabrics were composed of boa fabric, which is commonly used in mascot suits and plush dolls, and cloth reinforced with polyurethane foam. The tensile strength and the elongation were measured by the tensile strength test for clothes or clothing seams, in accordance with the standard JISL1096. In terms of appearance, red-green-blue (RGB) color values were obtained from photographs taken under the same light conditions to evaluate the color tone. A friction test was used to evaluate the tactile sensation. These results showed that EOG sterilization did not notably affect the properties of the fabrics; however, a single cycle of autoclave sterilization degraded the fabrics. Notably, the boa fabric shrunk and hardened. Thus, EOG sterilization, which does not feature elevated temperatures, may be an effective sterilization approach for these materials.

著者

沖野 友洋 永田 恵輔 高野 純一 小林 秀敏

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.21-00073, (Released:2021-09-17)

参考文献数

19

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The crash safety structure of the railway vehicles is important as one of the safety measures against the train crews and the passengers in the event of a collision accident. It is impractical to perform collision testing many times using the actual train unit to design the crash safety structure, whereby the numerical simulation is effective and it is important to validate the analytical accuracy. However, there are few studies of collision tests and numerical simulations using actual size carbody structures according to Japanese design standards, and even fundamental data have not been sufficiently obtained. Therefore, firstly, the authors performed the collision test of an actual-size partial stainless-steel carbody structure of a railway leading vehicle against a rigid wall and finite element analysis under the same condition as the test for the purpose of validating and improving the analytical accuracy of numerical simulation. Secondly, we carried out the collision test of the same carbody structure of a railway leading vehicle against a typical large dump truck in Japan and obtained the fundamental data such as the time histories of the impact compression load and the acceleration of the carbody structure as well as the deformational and fractural behavior of them. We also performed FE analysis under the same condition as the experimental test and compared the numerical result to the experimental one. As a result, the numerical result was consistent with the experimental result. Finally, we expanded the partial carbody structure model to a single carbody model and carried out the collision analysis of it against a large dump truck. Thereby, the impact deformation and fracture behavior of the railway carbody under the actual level-crossing accident were estimated.

著者

野中 朋美 中野 冠

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.783, pp.4024-4033, 2011 (Released:2011-11-25)

参考文献数

14

被引用文献数

4 6

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The paper proposes a carbon taxation scheme using life cycle assessment (LCA) for clean energy vehicles (CEVs). This taxation scheme can enable to be discussed tax amount, tax revenue and total CO2 emissions by changing the scenarios and parameters, such as: technology development, energy price and total driving distance. The authors figure out the tax rate 28.05[JPY/kg-CO2], which makes the hybrid electric vehicle's life cycle cost (LCC) less than that of conventional gasoline vehicles. The simulation results show that LCC after taxation of electric vehicles (EVs) have lowest total cost when battery cost is 0.14 times the 2007 cost and have lower total cost than that of GVs when driven more than 221,600 km. In addition, EVs have lowest emissions when driven more than 63,000 km considered CO2 emissions in the manufacturing phase, and it is expected that elders who drive shorter distances are best suited for hybrid electric vehicles and gasoline vehicles not electric vehicles considering LCCO2. The proposed tax system can provide consumers with an incentive to choose vehicles with lower CO2 emissions.

著者

鷺沢 忍

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:00214728)

巻号頁・発行日

vol.93, no.865, pp.989-993, 1990

被引用文献数

1

著者

小原 哲郎 大八木 重治 高藤 亮一 蔡 品

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.67, no.659, pp.1680-1686, 2001-07-25 (Released:2008-03-28)

参考文献数

14

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Experiments are carried out to investigate behavior of shock wave diffraction from a safety-engineering point of view. Because, once the shock wave is released into an ambience, high pressure and negative pressure lasting for relatively long period have possibility to cause serious damages against human bodies as well as general buildings. Therefore, it should be one of the most significant subjects to attenuate the shock wave efficiently within a short distance from the source. In this report, a cavity is installed at an open end of a shock tube and flow-fields behind diffracted shock wave are visualized using schlieren photography. In addition, piezo-electric pressure transducer is flush mounted on the surface of reflector, which is installed at test section, and pressure histories are recorded with wide frequency response. Lastly, numerical simulation using the TVD finite difference scheme is performed to compare with the experimental results. As a result, (i) the pressure histories on the reflector coincides well between the numerical and experimental results, (ii) flow-fields behind the shock wave are clarified, (iii) maximum pressure behind reflected shock wave can be attenuated by installing several cavities inside the open end of the shock tube.

著者

高藤 亮一 山中 昭央 小原 哲郎 蔡 品 大八木 重治

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.65, no.639, pp.3602-3607, 1999-11-25 (Released:2008-03-28)

参考文献数

12

被引用文献数

2 2

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As is well known when a shock wave is emitted from an open end of a tube, an expansion wave and a vortex ring are generated behind the shock wave. Furthermore, a contact surface, slip line and these wave interactions may cause considerably complicate flow-fields. In this study, shock waves of Mach number 1.3, 1.6 and 2.2 are produced utilizing diaphragm-less shock tube of 50 mm diameter and c. a. 10 m total length, and the flow-fields are visualized with an aid of schlieren optical techniques. A cylindrical reflector is installed at test section and stagnation pressure behind reflected shock wave is measured with wide frequency response. A numerical analysis is also carried out to investigate these flow-fields using Predictor-Corrector TVD finite difference scheme. As a result, (i) the contour of diffracted shock wave is well coincided between experimental and numerical results, (ii) pressure histories behind reflected shock wave are clarified, (iii) an empirical formula is obtained between Mach number, non-dimensional distance from the open end of the tube and non-dimensional pressure just behind reflected shock wave.

著者

神野 研一 村上 大介 小林 誠一 鳥垣 俊和 志澤 一之

出版者

一般社団法人 日本機械学会

雑誌

計算力学講演会講演論文集

巻号頁・発行日

vol.2002, pp.193-194, 2002

著者

近藤 恭三

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.65, no.516, pp.115-123, 1962 (Released:2017-06-21)

著者

鈴木 悠平 大隅 久

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.83, no.849, pp.17-00017-17-00017, 2017 (Released:2017-05-25)

参考文献数

11

被引用文献数

1

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A design method of time-optimal trajectory of quadruped robots from an initial position to a target position is developed for trot gait. The designed trajectory consists of three phases, acceleration phase, steady walk phase and deceleration phase. The time-optimal trajectory is designed in each phase and they are integrated so that the robot reaches the target position. Since the fastest walk trajectory in steady walk has already been obtained in our previous research, the time-optimal trajectories in the acceleration and deceleration phases are designed in a similar way to the previous study. First, all the possible trajectories in the search space with which the velocity of the robot reaches the previously obtained maximum velocity are designed in the state space of the robot. Next, they are checked whether the physical constraints and the constraint imposed by swinging legs are satisfied or not. Then the trajectory with the shortest time to reach the maximum velocity is chosen as the time-optimal trajectory among the trajectories satisfying all the constraints. The obtained time-optimal trajectories are tested by a quadruped walking robot SONY ERS-7 and the effectiveness of the developed method of designing time-optimal trajectory is verified.

著者

望月 康廣 鈴木 基継 西本 哲也 本村 友一 宇治橋 貞幸

出版者

一般社団法人 日本機械学会

雑誌

公開研究会・講演会技術と社会の関連を巡って : 技術史から経営戦略まで : 講演論文集 2016 (ISSN:24329487)

巻号頁・発行日

pp.324, 2016 (Released:2017-06-19)