著者
後藤 陽一 細貝 英実 原 文雄 阿部 靖則 田中 祥夫
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.64, no.625, pp.3342-3347, 1998-09-25
被引用文献数
7

In-pipe flaw causes a failure in air conditioning pipe system, and to prevent the failure, in-pipe flaw must be diagnosed regularly. For the diagnosis of it, the type and size of the flaw are important information, and a pulsereflection method is usually used, because of its simplicity, where the type and size of in-pipe flaw have an effect on an amplitude of its echo. In this paper, to judge the type and size of in-pipe flaws, we used the two kinds of the amplitude information about the echoes. One is the amplitude of the echo that is reflected from the inner surface of the pipe with the flaws. The other is the amplitude of the echo reflected from the normal surface of the pipe. We used wavelet analysis to obtain the amplitude information about the echoes in the ultrasonic pulse reflected. We showed the results of the in pipe flaw diagnosis by using a test pipe with the artificial flaws on its inner surface and classified the results of flaw diagnosis in three types. Finally, we proposed an estimation method of the size of the in pipe corrosion with some experimental results.
著者
佐藤 志保理 山口 明彦 竹村 憲太郎 高松 淳 小笠原 司
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
巻号頁・発行日
vol.2011, pp."1A1-O11(1)"-"1A1-O11(4)", 2011-05-26

In this paper, we study a method to translate the style of an input motion which is obtained by a motion capture system. For this aim, we model the difference of motions coming from the actor's attribute, such as gender and age. Especially, we focus on the difference coming from the gender, and model the difference of poses (joint angles) between males and females by using a Gaussian process regression. In training the model, we utilize Multifactor Gaussian Process Model to align the training set of motions in cyclic phase. In the experiments, we train the filter with walking motions of males and females, then we apply the filter to walking, running, and jumping motions of males. The results demonstrate that the filter successfully translates the motion into a womanish one.
著者
李 輝 野崎 勉
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.62, no.597, pp.1810-1818, 1996-05-25
参考文献数
8
被引用文献数
2

A new cross-correlation method, which is called a wavelet cross-correlation analysis and expresses the statistical cross-correlation of any signal in terms of period and time delay, is proposed and its main properties are presented. By analyzing two typical signals, the cross-correlations of components with different periods can be detected, and it is shown that wavelet cross-correlation can overcome the limitations of classical cross-correlation. As a practical application to the field of fluid mechanics, wavelet cross-correlation is employed to analyze cross-correlation relationships between χ-components of the fluctuation velocities at two points on opposite sides of the centerline and along the centerline of a plane turbulent jet in terms of period and time delay. From the distributions of the wavelet cross-correlation coefficient, similar structures of motions with various scales are shown, and the successive branching of vortex structures is observed. The period of vortex and apparent flapping motions can be easily determined in terms of period and time delay.
著者
浅見 敏彦 桃瀬 一成 細川 〓延
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.59, no.566, pp.p2962-2967, 1993-10
被引用文献数
3

This paper proposes an expression for design of optimal dynamic absorbers attached to damped linear systems. The classical expressions were derived from the assumption that the primary system has no damping. There are two optimization criteria in the design of the dynamic absorber : the fixed-points theory and the minimum variance criterion. In the fixed points theory, the dynamic absorber is optimally tuned and damped with respect to the primary system so that the two resonant amplitudes of the main mass are equal. In the latter criterion, however, the area under the power spectrum density curve of the main mass is adjusted to take the minimum value. The new expression proposed in this paper is based on the minimum variance criterion. A perturbation method is used to obtain the expression, and the accuracy of the perturbation solution is discussed.
著者
西原 修 松久 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.63, no.614, pp.3438-3445, 1997-10
参考文献数
6
被引用文献数
9

Fixed points design methods for dynamic vibration absorbers are very well-known in the field of vibration control and commonly applied for practical absorber design. However, they must be understood to be approximation methods from the point of view of their design criterion that the resonance amplitude magnification factor is minimized. In this study, the exact algebraic expressions of optimum tuning and damping parameters for the minimization of the largest resonance amplitude magnification factor of linear dynamic vibration absorbers have been derived for undamped primary systems. The existence of two equal height resonance points is reduced to a multiple root condition of an algebraic equation. The determinant is handled as an equation with respect to the resonance amplitude. It has became very clear that the fixed points theory design by Brock is highly accurate. In particular, it exhibits very small error in the practical mass ratio range, e.g., below unity. Algebraic solutions also exist for the resonance frequencies and the anti-resonance frequency. A numerical extension of the method is introduced in order to investigate the optimization problem for damped primary systems.
著者
浅見 敏彦 細川 〓延
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.61, no.583, pp.915-921, 1995-03-25
参考文献数
15
被引用文献数
5

This paper proposes an expression for design of optimal dynamic absorbers attached to damped linear systems. The classical expressions were derived from the assumption that the primary system has no damping. There are two optimization criteria in the design of the dynamic absorber : the fixed-points theory and the minimum variance criterion. In the fixed-points theory, the dynamic absorber is optimally tuned and damped with respect to the primary system so that the two resonant amplitudes of the main mass are equal. On the other hand, in the latter criterion the area under the power spectrum density curve of the main mass is adjusted to take the minimum value. The new expression proposed in this paper is based on the fixed-points theory. However, there are no fixed points in the resonance curves of the damped linear systems, so the analytic procedure becomes impossible. Therefore a perturbation method is used to obtain the expression, and the accuracy of the solution is discussed.
著者
九鬼 潤一 戸田 和之 山本 誠
出版者
一般社団法人日本機械学会
雑誌
年次大会講演論文集 : JSME annual meeting
巻号頁・発行日
vol.2002, no.3, pp.297-298, 2002-09-20

Sand erosion is a phenomenon where a solid particle impinging to a wall causes to damage to a part of the wall. It occurs on the wall in a lot of machines such as airplane, ship and pump. It is well known that performance and lifetime of the equipment are severely degraded due to sand erosion. In this study, we compute sand erosion phenomena in a particle separator which is implemented into the propulsion system of a helicopter, in order to clarity the change of surface geometry and flowfield and the influence on the separator effectiveness with the proceeding of erosion. Moreover, we reveal the difference of the trajectories when material and particle diameter is parametrically changed.
著者
徳田 正孝 大橋 義夫 大橋 義夫
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. A編 (ISSN:03875008)
巻号頁・発行日
vol.48, no.426, pp.239-247, 1982-02-25

多結晶金属の塑性異方性の発達に関する基本的特性,たとえばおくれ効果,記憶減退性,予ひずみの影響の飽和などは,理想化された簡単な多結晶モデルを用いて説明される.とくに単結晶間の相互作用により生じる内部応力は,ここで支配的な役割を果たす.さらに,このモデルによる計算結果は,ひずみ経路の折れ点後あるいはひずみ経路の曲率部分にみられる一連の複雑な塑性変形挙動を定性的な意味で的確に表した.
著者
山本 悠理 竹村 研治郎
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
巻号頁・発行日
vol.2010, pp."1A2-E08(1)"-"1A2-E08(4)", 2010

An interface that presents variable sense is paid attentions from virtual reality researches. This paper presents an ungrounded force feedback device using the gyroscopic effect. An ungrounded force feedback device includes the Control Moment Gyro (CMG) that generates the torque due to the gyroscopic effect, resulting in making the system produce the sense of force to an operator. Four CMGs are arranged in pyramid form (4-CMG system), so that the plural CMGs are simultaneously driven to synthesize the torque. We experimentally verify the performance of the developed device. Concretely, we measured the stimulus threshold and evaluate the perception characteristic of an ungrounded force feedback device.
著者
武田 好央 中込 恵一 新村 恵一
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. B編 (ISSN:03875016)
巻号頁・発行日
vol.62, no.599, pp.2887-2894, 1996-07-25
被引用文献数
48

There is a gradient of fuel concentration in the spray of conventional direct-injection diesel engines. Therefore, a region of stoichiometric mixture ratio exists in the injected spray and a high concentration of NO_χ is produced. In this study, fuel injection timing was widely advanced to promote the mixing of fuel and air. Using this injection method, the engine could be driven with premixed lean diesel combustion (PREDIC), and NO_χ emissions were greatly reduced. To avoid the fuel spray contacting the cylinder liner, the fuel was injected by two side injectors simultaneously. The two sprays from the side injectors collided with each other and remained in the center region of the cylinder. Thus mixing of fuel and air was promoted by a long ignition delay period. In the case of conventional injection methods, NO_χ could not be reduced to under 400ppm (λ=2.7). In contrast, in the case of PREDIC, NO_χ emissions were reduced to as low as 20ppm (λ=2.7).
著者
坂本 誠馬 長谷川 淳哉 田多 輝洋 鳴尾 丈司 溝田 武人
出版者
一般社団法人日本機械学会
雑誌
シンポジウム: スポーツ・アンド・ヒューマン・ダイナミクス講演論文集 : symposium on sports and human dynamics
巻号頁・発行日
vol.2011, pp.532-535, 2011-10-30

The new NPB Ball was adapted to the Japanese NPB from this year. Compared with the old NPB ball and new one, seem height and width became 0.2[mm] lower and 1.0[mm] wider respectively. In this report, aerodynamics characteristics are measured by using wind tunnel tests. Some calculations of flight trajectory for pitcher's throwing ball and batter's hitting one are conducted.
著者
橋場 邦夫 寺尾 憲 久納 孝彦
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. C編 (ISSN:03875024)
巻号頁・発行日
vol.64, no.620, pp.1339-1346, 1998-04
被引用文献数
9

The theory of squeeze film pressure and the theory of acoustic radiation pressure have been generalized to a new theory in this study. When the two fiat faces are separated by a compressible fluid film, a dynamic pressure is generated in their normal direction by the oscillation of the faces. One of the authors derived a fundamental equation for the phenomenon considering both the inertia and the viscosity of the fluid. In case of neglecting the inertia effects and assuming the isothermal change, the equation is reduced to the Reynolds equation used in the conventional lubrication theory. In this paper, an analytical solution of the Reynolds equation on the adiabatic squeeze film is presented. The results show that compressibility effects of the fluid are dominant at high squeeze numbers. The relationship between the squeeze film pressure and Rayleigh radiation pressure is also investigated theoretically.
著者
有馬 誠一 上加 裕子 神村 泰地 仁科 弘重 羽藤 堅治 高山 弘太郎
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
巻号頁・発行日
vol.2011, pp."1A1-A02(1)"-"1A1-A02(2)", 2011-05-26

The autonomous driving unit using the regression reflective type laser sensor and the laser range sensor has been developed aiming at automation and robotization of various work in the intelligent greenhouse (harvesting and pest control) and plant diagnosis information measurement. Some study cases of on-board equipped system of harvesting, pest control and plant diagnosis information measurement are reported.
著者
山田 嘉昭
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
巻号頁・発行日
vol.2011, pp."1P1-A03(1)"-"1P1-A03(2)", 2011-05-26

Okayama University established an actuator research center as research and development about the actuator and a foothold of high specialized personnel training in November, 2008. The activity purpose of the center establishes 「The field crossing type engineering system」 across the fields border of mechanical engineering, electrical engineering, materials engineering, and it is to perform the research and development of an epoch-making actuator and practical education research activities.