著者

桜井 康雄 鈴木 教之 饗庭 健一 吉成 考正 川島 清隆 木原 和幸

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.788, pp.1163-1169, 2012 (Released:2012-04-25)

参考文献数

4

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In this paper, a component restricting pressure change caused by oil temperature change is proposed. One of the merits of an oil-hydraulic system is to keep the value of oil pressure when pressurized oil is enclosed in a container. However, it is impossible to keep the value when the temperature of the oil is changed. Using a pressure control sub-system to prevent it, the whole system becomes complicated. In addition to it, the energy is consumed when the pressure is adjusted by the quantity of the oil flowing into or out the container. From these view points, it is effective to develop the component which prevents the pressure change according to the oil temperature change without the control of the quantity of the oil. Therefore, in this paper, a component to prevent the pressure change based on the oil temperature change is proposed to make the merit of oil-hydraulic system certain when the temperature of the oil is changed. And, in the cases where the temperature of the oil is increased and where the temperature of the oil is decreased after it is increased, the basic characteristics of the component investigate experimentally.

著者

中川 健一 長谷川 裕晃 村上 正秀 大林 茂

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.856, pp.17-00165-17-00165, 2017 (Released:2017-12-25)

参考文献数

13

被引用文献数

1

---

Badminton is one of the most popular sports in the world and is famous as the sport having the fastest initial velocity of a batted ball among all ball games. Initial velocity immediately after smashing may reach up to 408 km/h (113 m/s) at maximum. A badminton shuttlecock generates significant aerodynamic drag and it was confirmed that the high deceleration characteristics was related to the slots located at the leg portion of a shuttlecock in the previous study. Turnover refers to the flipping experienced by a shuttlecock when undergoing heading change from nose pointing against the flight path at the moment of impact and a shuttlecock indicates the aerodynamically stable feature for the flip movement just after impact. The purpose of this study is to investigate the effect of gaps on the aerodynamic stability (turnover stability) of a badminton shuttlecock during the flip phenomenon. In the present study, the flow field around the shuttlecock during impulsive change of an angle of attack (flip movement) was measured by using the smoke flow visualization and the behavior of the shuttlecock during the flip movement was evaluated in comparison with that of the conic model (with no gaps). The turnover stability of a badminton shuttlecock is affected by gaps of the shuttlecock skirt.

著者

富永 萌子 武村 泰範 石井 和男

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.2P1-K07, 2017 (Released:2017-11-25)

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In the soccer games, the behavior selection of each player changes depend on the positional relationship of the ball and the every player’s position on the field. The player closest to the ball near the opponent team’s goal aims at a shot, and the farthest player waits at a position where he can return at any time to his own goal to protect. Currently most of RoboCup soccer teams keep the same strategy during the game so that the result of game depends on the ability of each player like speed of robot, quality of localization, obstacle avoidance and ball handling. Next issue for the robot intelligence is collaborated team behavior and strategy. The autonomous soccer robots are required to behave cooperatively and make decision using environment and game situation. In this research, the team strategy is analyzed based on the positions of human player using Self-Organizing Map (SOM).

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.43, no.281, pp.413, 1940-08-01 (Released:2017-06-21)

著者

熊谷 正朗

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.109, no.1057, pp.968-969, 2006-12-05 (Released:2017-06-21)

著者

河越 正羽 水谷 義弘 轟 章 松崎 亮介 安岡 哲夫

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A編 (ISSN:18848338)

巻号頁・発行日

vol.79, no.801, pp.555-562, 2013 (Released:2013-05-25)

参考文献数

27

被引用文献数

1 3

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In this study, a new welding method which utilizes conductivity of CFRTP (Carbon Fiber Reinforced Thermo-Plastic) is proposed. Electrical current is applied through the CFRTP single-lap joints in thickness direction. Since resistance of joining surface is the highest in the current path, the joining surface is preferentially heated by Joule heating. In this study, spot welding and surface welding were conducted. By applying constant voltage of 5.0V or 10.3V, the joint-surfaces were heated above melting temperature Tm of the material and were welded. In order to evaluate lap-shear strength (LSS) of welded joints, tensile lap-shear strength tests were conducted. As a result, the tensile lap-shear true stress of spot welding is 31.0MPa and LSS of surface welding is 22.0MPa. These strengths were comparable to those that were welded by traditional resistance welding method. It is also found that LSS is changed with welding pressure of joint parts.

著者

山田 和明 大倉 和博

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C編 (ISSN:18848354)

巻号頁・発行日

vol.78, no.792, pp.2950-2961, 2012 (Released:2012-08-25)

参考文献数

17

---

Reinforcement learning approaches attract attention as the technique to construct the mapping function between sensors-motors of an autonomous robot through trial-and-error. Traditional reinforcement learning approaches make use of look-up table to express the mapping function between the grid state space and the grid action space. However the grid size of the state space affects the learning performances significantly. To overcome this problem, many researchers have proposed algorithms using neural networks to express the mapping function between the continuous state space and actions. However, in this case, a designer needs to appropriately set the number of middle neurons and the initial value of weight parameters of neural networks to improve the approximate accuracy of neural networks. This paper proposes a new method to automatically set the number of middle neurons and the initial value of the weight parameters of neural networks, on the basis of the dimensional-number of the sensor space, in Q-learning using neural networks. The proposed method is demonstrated through a navigation problem of an autonomous mobile robot, and is evaluated by comparing Q-learning using RBF networks and Q-learning using neural networks whose parameters are set by a designer.

著者

鈴木 明宏 茂庭 優貴 石井 賢治 藤原 誠助 永富 良一

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 (ISSN:21879761)

巻号頁・発行日

vol.83, no.849, pp.16-00450-16-00450, 2017 (Released:2017-05-25)

参考文献数

10

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Amount of daily physical activity is strongly associated with the prevalence of lifestyle-associated diseases, and thus maintaining a certain level of physical activity is recommended. Amount of physical activity, namely energy expenditure, is commonly estimated from linear regression analysis of oxygen uptake during steady-state exercise of different intensities. Short-duration exercise, mainly walking lasting less than 3 minutes, has been reported to account for over 90% of the daily energy expenditure of healthy adults. The estimation of energy expenditure by ACSM Metabolic Equations used well, however, is based on steady-state exercise of more than 5 minutes, and energy consumption of shorter duration exercise is not commonly considered. Oxygen consumption remains elevated for some period of time after exercise. Then, the estimation of energy expenditure for short duration exercise must include excess post-exercise oxygen consumption (EPOC). The amount of EPOC change in duration exercise. Therefore, we attempted to elucidate the energy expenditure for VO2 kinetics. Ten healthy participants aged 19-54 y walked and ran for 1, 3 and 5 minutes on a treadmill at constant speed. Oxygen consumption during and post-exercise was measured using a portable gas analyzer in breath-by-breath mode. A best-fit exponential equation to estimate oxygen consumption from exercise duration and walking speed was generated. The root mean square (RMS) of estimate equations was calculated using Leave-one-out cross validation. The RMS(1.44~2.14 ml/kg/min) was lower, and the results of the Bland-Altman analysis revealed neither fixed nor proportional bias with the exception of the decent walking and running. An equation for the estimation of oxygen consumption at shorter durations of exercise was successfully generated. Accumulation of additional data may further improve the equation.

著者

橋本 博文 今井 栄一 矢野 創 渡辺 英幸 横堀 伸一 山岸 明彦

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

2016

被引用文献数

1

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The mechanical thermometer using a bimetallic strip coil was developed for the Tanpopo mission. The Tanpopo mission is a multi-year passive exposure experiment for astrobiology exposure and micrometeoroid capture onboard the Exposed Experiment Handrail Attachment Mechanism (ExHAM) at the Japanese Experiment Module 'Kibo' (JEM) Exposed Facility (EF) on the International Space Station (ISS). The Tanpopo mission apparatuses were launched by the SpaceX-6 Dragon CRS-6 on April 14 2015, from the Cape Canaveral Air Force Station in the U.S.A. Since its microbial exposure experiment requires recording the maximum temperature that the Tanpopo exposure panel experiences, we have developed a mechanical thermometer with no electric power supplied from the ExHAM. At a given time and orbital position of the ISS, the thermometer indicator was video-imaged by the extravehicular video camera attached to the Kibo-EF and controlled from the ground. With these images analyzed, we were able to derive the maximum temperature of the Tanpopo exposure panels on the space pointing face of the ExHAM as 23.9±5 °C. Now this passive and mechanical thermometer is available to other space missions with no electric supplies required and thus highly expands the possibility of new extravehicular experiments and explorations for both human and robotic missions.

著者

山下 興家

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.41, no.256, pp.673-675, 1938

著者

田中 耕太郎 根岸 明 増田 俊久

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 B編 (ISSN:03875016)

巻号頁・発行日

vol.58, no.553, pp.2857-2862, 1992-09-25 (Released:2008-03-28)

参考文献数

13

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The replacement of working fluid of the alkali metal themoelectric converter (AMTEC) is eminently suitable for achieving higher performance under lower operating temperatures. Potassium is a reasonable condidate because it has lower latent heat of vaporization and higher vapor pressure than sodium over the AMTEC operating conditions. The performance of the AMTEC cycle with potassium as the working fluid has been evaluated and discussed based on the recently reported ionic conductivity data of potassium-β"-alumina solid electrolyte. The calculated results show that the replacement of working fluid increases the peak efficiency from 28% to 31% at 1100K with 1mm thick β"-alumina solid electrolyte. If the thinner solid electrolyte is practically developed, the improvement of the performance can obviously be recognized because of the decrease of ionic conductivity.

著者

佐藤 明

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.61, no.583, pp.933-938, 1995-03-25 (Released:2008-03-28)

参考文献数

15

---

The object of the present study is to evaluate the performances of various microcanonical molecular dynamics algorithms. To do so, the divergence times and energy fluctuations are discussed for a model system, i. e. a three-dimensional Lennard-Jones system under various conditions of number densities and temperatures. The results of the evaluations of superiority or inferiority of algorithms are as follows. The velocity Verlet, leapfrog, and Beeman algorithms are significantly superior to the other algorithms such as the 4-value Gear algorithm since a system does not diverge and the energy conservation law is reasonably satisfied for much larger time intervals. Although these three algorithms show approximately the same performance concerning the properties of divergence times and energy fluctuations, we can conclude that the velocity Verlet algorithm is the most suitable for molecular dynamics simulations of flow problems, since this algorithm is easy to use, requires less computer memory, and evaluates molecular positions and velocities at the same time steps.

著者

平島 健一 木村 清和 広瀬 幸雄

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.57, no.542, pp.2516-2522, 1991-10-25 (Released:2008-02-21)

参考文献数

7

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By using the theoretical results for closed-form analytical solutions of in-plane problems inclusion under point forces, dislocations and so on, several numerical examples are shown by many graphical representations. The previous results published by several authors can be included as particular cases of our solutions.

著者

松本 浩乃 窪田 佳寛 大石 正行 望月 修

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.15-00389-15-00389, 2016 (Released:2016-01-25)

参考文献数

13

---

The typhoon often causes a serious damage of the apple before harvest. Many apples fall from trees by the strong wind. These apples are bagged to protect them from insects and control sun light for the apples coloring while they are ripening on the tree. We conceive that the wind-force acting on the bagging apple exceeds one without bag. Thus, we investigate the drag coefficient CD of the bagging apple by measuring drag force acting on an apple model experimentally. The shear stress on a stem under the typhoon is estimated for understanding one of mechanism for dropping apple due to the strong wind. The shear stress of a stem whose apple encounters the maximum velocity recorded at the past typhoon is estimated by the obtained CD. The drag force of the bagging apple becomes bigger than that of the apple without the bag. The bagging apple is not a rotational symmetry so that the CD is different with the different wind direction. The angle against the flow of model with the bag is changed from 0 deg. to 90 deg. to understand the influence of shape, since CD depends on the geometry. The shear force acting on the stem depends on the drag. Thus, the shear stress is larger if the drag is larger. The obtained shear stress is compared with allowable shear stress of a real tree. We suggest that there is possibility to decrease damage if we can decrease the drag of the bagging.

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 (ISSN:21879761)

巻号頁・発行日

vol.80, no.820, pp.TEP0377-TEP0377, 2014 (Released:2014-12-25)

参考文献数

30

被引用文献数

1

---

In order to investigate the process of accident of Fukushima Nuclear Power Plants, an accident scenario of Fukushima Daiichi Nuclear Power Plant, Unit 1 is analyzed from the data open to the public. Phase equilibrium process model and adiabatic expansion model were introduced. Original data reported in the first stage of the accident were examined to clarify the behavior of the isolation condensers (ICs) which are generally believed unfunctional after the arrival of Tsunami and station blackout. The original data and observation reports verified that the so called “fail safe” system to close the valves in IC did not work properly due to the shutdown of AC power. The reports also showed the evidence that the operators injected water to the storage tank of IC. We proposed a scenario that IC was operational until approximately at 3/12 3:00, small leakage occurred at the reactor pressure vessel (RPV) at the initial stage of the accident, the RPV ruptured at 3/12 6:20, and it ruptured again in approximately at 3/12 16:00. We assumed that PCV ruptured at 3/12 3:00, and the area of rupture did not change after the hydrogen explosion occurred at 3/12 15:36. The present analysis model describes the data measured at the accident, and many evidences and witnesses reported at the early stage of the accident. We also simulated according to the scenario of Tokyo Electric Power Company (TEPCO) that the ICs did not work after the Tsunami arrival. The estimation by the present analysis agrees with the TEPCO's one, however, there are many discrepancies that cannot explain the behavior of the reactor accident.

著者

橋本 博文

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.101, no.950, 1998

参考文献数

2

著者

武田 雄策 大黒谷 陽子 村瀨 健二 大坪 智範 橋本 悟 伏見 亮 民谷 謙

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.807, pp.4039-4046, 2013 (Released:2013-11-25)

参考文献数

10

被引用文献数

1

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This paper discusses a design methodology of vehicle interior layouts and shape matching visual space KANSEI characteristics considering human visual direction perception. Relationships between perception and KANSEI of direction need to be quantified for the vehicle interior design based on multidisciplinary optimization among the KANSEI evaluation values of human visual direction and the other vehicle performances. Experiments were carried out for some interior layouts and shapes, which were displayed by immersive virtual reality system, with some subjects who develop the vehicle interior package. And, KANSEI evaluation values were measured by visual analog scale method for recording continuously. Experimental results demonstrate that the perception and KANSEI of direction have changes like sigmoid curve according to layouts and shapes. Also, KANSEI response surface, which was derived by using linear basis function models for expressing its characteristics, was applied to the A pillar design study.

著者

秋山 修 加藤 千幸 河手 大輔

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B編 (ISSN:18848346)

巻号頁・発行日

vol.78, no.795, pp.1903-1918, 2012 (Released:2012-11-25)

参考文献数

21

被引用文献数

3 4

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Mechanism of particle separation in a cylindrical cyclone separator has been fully clarified by a combined numerical method of large eddy simulation and a particle tracking method. The former resolves all the important vortical structures in the separator while the latter inputs the instantaneous flow fields computed by the LES and computes trajectory of each particle by considering Stokes drag as well as gravity force. Particle collection efficiency predicted by the proposed method has been compared with the experimental data measured for two cylindrical cyclone separators with several sets of particle diameters. The results showed that the collection efficiency has been quantitatively predicted by the proposed method, which confirms that the method can be used for the engineering design of such a cyclone separator. Detailed investigation of the particle trajectories predicted by the present method has clarified the mechanism of particle separation of a cylindrical cyclone separator. Those particles that are successfully collected by the separator move outward in the swirl flow and are collected when the swirl flow changes its direction at the bottom of the separator. The essential mechanism of this particle separation is due to the centrifugal forces acting on the particles. Three types of particle trajectories have been identified for those particles that are exhausted from the cyclone separator together with the swirl flow. More than half of the uncollected particles are trapped by longitudinal vortexes. The unsteady longitudinal vortexes and vortex rope drastically decrease collection efficiency.

著者

Tatsushi TOKUYASU Shimpei MATSUMOTO

出版者

一般社団法人 日本機械学会

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.8, no.1, pp.94-103, 2013 (Released:2013-06-06)

参考文献数

9

被引用文献数

1 3

---

The saddle height of a cycle road racer influences the competitive performance of the cyclist. Cyclists can adjust the saddle height carefully according to their kinesthetic sense while riding a bicycle. The saddle height control system we have developed consists of a saddle height control device and a measurement instrument for a surface electromyogram (SEMG). The evaluation criteria for the saddle height based on SEMG signals, which are measured from the leg muscles during pedaling exercise, are established. Our experiments indicate that the saddle height was controlled at a relatively low level regardless of the cycling level of the subjects. The effects of muscle fatigue due to pedaling exercise are suspected to affect these experimental results.

著者

Masanori ARITOMI Toshihiro ADACHI Shigeki HOSOBUCHI Noriyuki WATANABE

出版者

一般社団法人 日本機械学会

雑誌

Journal of Power and Energy Systems (ISSN:18813062)

巻号頁・発行日

vol.6, no.3, pp.412-422, 2012 (Released:2012-10-16)

参考文献数

4

被引用文献数

1 2

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In the joint research and development of treatment systems of cooling water for cutting asphalt pavement surface with our authors' group, the liquid-solid separation technology by flocculating and settling technology, and the flocculants for the use of systems were developed. In this paper, the developed flocculating and settling technology and the flocculants are discussed first. Next, the demonstration tests of decontamination technology on the contaminated water in swimming pools in an elementary school located at Motomiya City, Fukushima Prefecture had been conducted by use of the stationary purification system of contaminated water and the flocculants compounding with or without iron ferrocianide developed by the preliminary test. It was clarified from the results that ionized cesium (Cs) rarely exists in the stagnant water in pools, ponds, lakes and so on at the time when nine months have passed since Fukushima Dai-ichi nuclear power plant accidents. Further, it is necessary to use the flocculants compounding iron ferrocianide in the case where ionized Cs exists in water. From the above-mentioned results, the following problems were pointed out: One problem was cyanide dissolution in the purified water and the other one was the dissolution from the dehydration sludge. Finally, the high-performance mobile purification units of contaminated water which is capable for carrying with trucks have been developed, and the demonstration test was performed in Minami-soma City, Fukushima Prefecture to purify the contaminated water in a pond and generated by the high-pressure water washing in a Public Hall. From the test results, it was made clear that the dehydration sludge separated by liquid-solid settling of the contaminated water of around 1,000Bq/l became a high radiation dose of about 185,000Bq/l.