著者
劉 孝宏 末岡 淳男 白水 健次 江村 篤裕 中野 寛
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.689, pp.30-37, 2004-01-25 (Released:2011-03-04)
参考文献数
11
被引用文献数
2 2

This paper deals experimentally with the squeal and chatter phenomena generated in mountain bike disk brakes. First, the authors performed the traveling test using actual bicycle on downhill road in a mountain. As the results, there are two kinds of frictional self-excited vibrations in the bicycle disk brakes called by squeal with frequency of 1 kHz and by chatter with frequency of 500 Hz. In order to regenerate the squeal and the chatter, a bench test apparatus by actual bicycle was set up and their characteristics were experimentally examined. By using the bench test apparatus, it was made clear that their frequencies were independent of temperature of pad and rotating speed of rotor, and the chatter was generated in a certain limited region of high temperature though the squeal occurred in arbitrary temperature region of pad.
著者
末岡 裕一郎 北 卓人 石川 将人 杉本 靖博 大須賀 公一
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C編 (ISSN:18848354)
巻号頁・発行日
vol.79, no.801, pp.1718-1727, 2013 (Released:2013-05-25)
参考文献数
15
被引用文献数
2 2

In this paper, we discuss some phenomena of obstacle clustering by distributed autonomous robots, in the light of space-discretization (or cellular automata) approach. This work was motivated by Swiss Robots which collect scattered obstacles into some clusters without any global information nor intelligent concentrated controller. Then we define fundamental event rules in this cellular world, and introduce two types of local rules for robot action: one is the Push & Turn rule, which can collect obstacles, the other is Pull & Turn rule, which can scatter obstacles. By defining several indices (ratio of immobile obstacles, ratio of moved obstacles), we investigate the dynamic equilibrium of obstacle clustering by heterogeneous agents. And, this paper also presents a control method of ratio of immobile obstacles from the estimation of each robot's local information even if all the states of obstacles cannot be measured.
著者
吉武 裕 末岡 淳男 森山 智樹 山崎 正則
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. C編 (ISSN:03875024)
巻号頁・発行日
vol.66, no.646, pp.1785-1792, 2000-06-25
被引用文献数
6

This paper deals with the quenching problem of self-excited vibrations by using a device composed of a Hula-Hoop and a generator. This device is also additionally able to generate electricity. The Runge-Kutta-Gill method is applied to the numerical analysis of a Rayleigh's type self-excited system with the device. The solutions obtained are divided into two main categories ; periodic solutions and chaos accompanied by Hula-Hoop's vibration and rotation. An optimum approach for quenching the self-excited vibration was discussed. As a result, it was clarified that for the optimum design of the device there existed a certain relation among the moment of inertia, the mass of Hula-Hoop and the capacity of generator, and the vibration at that time was chaos as in the impact damper which we analyzed before. The condition of maximum generation of electricity was not equal to that of minimum vibration amplitude of the self-excited system. An experiment was performed to quench vortex-induced vibration and to generate electricity by using the device. The experimental results agreed well qualitatively with those from the numerical computational analysis.
著者
中野 寛 末岡 淳男 劉 孝宏 家藤 英世 折居 利昭 中江 貴志
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:03875024)
巻号頁・発行日
vol.72, no.720, pp.2373-2381, 2006-08-25 (Released:2011-03-04)
参考文献数
8
被引用文献数
2 4

This paper deals with the occurrence mechanism of the squeal phenomena generated in a new type of bicycle disk brake unit and its countermeasure experimentally and analytically. It was made clear that squeal was in-plane vibration in the direction of disk surface with frequency 650 Hz caused by frictional characteristics with negative slope with respect to the relative velocity, and was generated in the vibration system including brake unit and spokes, in the same manner of old type of disk brake unit. The countermeasure against squeal by using a dynamic absorber was conducted. The simple analytical model of the bicycle disk brake system was set up. Some features of squeal phenomena and the optimal design of dynamic absorber for quenching squeal were made clear analytically and it was confirmed that the analytical results agreed well with the experimental ones.
著者
末岡 淳男 井上 卓見 松崎 健一郎 高山 佳久 劉 孝宏
出版者
九州大学
雑誌
萌芽研究
巻号頁・発行日
2003

高速増殖炉ヘリカル伝熱管深傷プローブの振動によるセンサノイズの原因とその対策を,モックアップによる実験と数値シュミレーションによって明らかにした.得られた結果は以下のようにまとめられる.(1)ECT(Eddy current testing)プローブを静止させて蒸発管内で圧縮空気だけを流しても,プローブには振動は発生しないが,プローブの圧送時には振動を生じる,すなわち,プローブの振動の原因は流体力ではなく,蒸発管内壁とプローブにあるフロートとの間の摩擦と考えられる.(2)ECTプローブの挿入過程では,挿入距離の増大に伴ってプローブの振動が激しくなる.ヘリカル管の中間部を過ぎると,約20HZの卓越した振動数で振動し,それに伴ってRF(Remote field)ノイズも大きくなる.そのとき,ECTプローブは軸および径方向に連成振動をしており,RFセンサは尺取り虫的な動きをする.一方,引戻過程では,卓越した振動数を持つ振動は発生せず,振動レベル,RFノイズとも挿入過程よりも低い.(3)挿入時には,ECTプローブはヘリカル伝熱管の内径側に張り付き,引戻時には,逆に外径側に張り付くように圧送される.したがって,挿入時および引戻時で,ECTプローブにはそれぞれ張力および圧縮力が作用している.(4)ECTプローブの搬送速度を高くするほど,圧送用の空気量を多くするほど,ヘリカル直径を小さくするほど,ECTプローブの軸および径方向振動もRFノイズも大きくなる.(5)ECTプローブの径方向の振動は,先端にいくほど大きい.また,RFノイズは励磁センサと検出センサの径方向相対振動の大きさと相関があるが,軸方向振動とは相関がない.(6)RFノイズを最小化するためには,6m以上で,曲げ剛性が比較的低い先導プローブを持つECTプローブを構成することである.(7)伝達影響係数法を適用して,大規模なプローブ列を対象とした流体による搬送力を含む摩擦振動を解析した結果,モックアップの実験結果とほぼ同様な数値計算結果を得ることができた.
著者
佐藤 錬太郎 弓巾 和順 近藤 浩之 水上 雅晴 室谷 邦行 末岡 実 山際 明利 名畑 嘉則 小幡 敏行
出版者
北海道大学
雑誌
基盤研究(B)
巻号頁・発行日
2006

国際的な学術動向を踏まえた上で研究交流を推進し、国内外の研究者と協力関係を構築した。最終年度には、中国の科挙学会「中華炎黄文化研究会科挙文化専業委員会」及び台湾国家科学委員会研究計画「清代經典詮釋方法與理論的轉向」の協力を得て、2009年8月に北海道大学において、「科挙と中華伝統文化」を主題とする科挙学国際シンポジウムを開催し、国内10名国外20名の科挙研究者を招聘し、科挙学の最新の研究成果を発表した。
著者
津田 吉広 田村 英之 末岡 淳男 松岡 寛憲
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. C編 (ISSN:03875024)
巻号頁・発行日
vol.60, no.578, pp.3300-3307, 1994-10-25

The characteristic which the Duffing oscillator with a softening spring property under harmonically stimulating force presents in the main resonant region has been investigated numerically. With regard to the structure which the system exhibits in this region, there exists another branch which appears due to bifurcation from the resonant branch at a certain frequency, in addition to the resonant and nonresonant branches. It has been clarified that many kinds of periodic solutions exist in the region between this new branch and the resonant one. Furthermore, besides the traditional harmonic solutions, i. e., resonant and nonresonant solutions, it has been shown that another harmonic solution appears, although it is unstable. This unstable solution enables us to reasonably explain the constitution of attractors in this resonant region. Chaotic phenomena, which appear due to period doubling bifurcation also exist.