著者

北林 研人 石原 匡 鞍谷 文保 吉田 達哉 小出 俊雄 水田 泰次 長村 光造

出版者

一般社団法人 日本機械学会

雑誌

Dynamics & Design Conference 2016 (ISSN:24242993)

巻号頁・発行日

pp.340, 2016 (Released:2017-06-19)

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Cymbals are thin domed plates used as percussion instruments. When cymbals are stuck, they vibrate and radiate sound. Cymbals are made through spin forming, hammering, and lathing. The sound radiated from a cymbal depends on its vibration characteristics that are determined by the shape and dimension. The hammering produces plastic deformation on the cymbal's surface, generating residual stresses throughout it. Although the vibration characteristics are changed by the hammering to adjust cymbal sound, the effect of the hammering on the cymbal sound is not clear. In this paper, we reveal the effect of the hammering on the vibration and the sound radiation characteristics. The stress distribution within the cymbal produced by hammering is reproduced by thermal stress analysis and the change in natural frequency of the modes are calculated by the vibration analysis with the stress distribution. The change (i.e., increase or decrease) in natural frequency for each mode is explained by the stress and modal strain energy distributions.

著者

山本 茂 東 倖成 髙木 山河 堀川 徳二郎 山崎 之博 宇治川 弘人

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.88, no.915, pp.22-00097, 2022 (Released:2022-11-25)

参考文献数

12

被引用文献数

1

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Strip walking is an unstable lateral movement in a hot strip finishing mill that causes the strip to crash into the side guides, resulting in a tail pinch where the strip is rolled in a folded state. Strip walking should be appropriately controlled to prevent tail pinches, and an adequate mathematical model is essential to design the strip steering control. In this paper, the traditional model and a recently proposed model representing strip walking are numerically compared, and the latter is shown to characterize the details of the actual phenomenon. Such a mathematical model derivation makes it possible to use model predictive control to optimally control the strip walking, considering the rate limit constraint of the actuator. However, model predictive control requires time-consuming optimization computation. Thus, control performance deteriorates with longer control periods. In this paper, we propose a new model prediction control method to reduce optimization computation time with discretized control input that enables fast discrete optimization instead of slow continuous optimization. It is also shown that fixing the misalignment between the roll and steel strip centers is insufficient to prevent the tail pinch. Moreover, it is vital to suppress the rotational motion of the steel strip by using numerical simulations.

著者

芝田 京子 井上 喜雄 岩田 祥孝 片川 準也 藤井 涼

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.791, pp.2483-2495, 2012 (Released:2012-07-25)

参考文献数

33

被引用文献数

4 9

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Lumbago occurs when load causes malformation of the flexible intervertebral disks of the lumbar vertebrae. The conventional method of measuring load on the intervertebral disk is an invasive method in which the internal pressure of the intervertebral disk is measured by directly inserting an electrode. In this study, intervertebral disk load is derived indirectly by the noninvasive estimation method that uses three-dimensional motion analysis system and signal processing to estimate the shape of the lumbar vertebrae. Specific estimation method is shown as follows. First, vertebra is assumed to a rigid body. Next, lumbar vertebrae are approximated with an arc using 3-D positional coordinates. Finally, average of the intervertebral gap is estimated. Accordingly, because the proposed method only entails applying markers to the surface of the back and taking pictures with cameras, it is safe and does not require surgical procedures. Furthermore, this method allows estimation of intervertebral disk load in a moving subject. In this paper, the proposed method is described in detail. And an experiment in which intervertebral disk load is estimated from stationary postures is executed. Moreover the proposed method is compared with the conventional method. As a results, the experiment shows that the proposed method is effective in that the magnitude correlation tendencies of intervertebral disk load estimated with the proposed method are qualitatively consistent with the tendencies calculated from actual measurements of internal pressure.

著者

花之内 健仁 松岡 連太郎 青木 僚汰 森田 崇裕 境 慎司

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.88, no.907, pp.21-00151, 2022 (Released:2022-03-25)

参考文献数

12

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Ultrasound transmission gel has been normally used as a material fills the gap between the transducer of the ultrasound and patient’s skin. Alternatively, however, it can be used as a trial bioink for the 3D bio-printer, which is identified as one material for checking its printability at the preliminary phase. The purpose of this study was to clarify whether the ultrasound transmission gel can be used as the trial bioink. For this purpose, we investigated the viscosity of some kinds of the ultrasound transmission gel, and compared with commercially available one. And also we measured the width of the printed lines with the ultrasound transmission gel in comparison with the perspective width. According to our results, we concluded that the ultrasound transmission gel can be used as the trial bioink as long as selecting appropriate viscosity type.

著者

松田 昇一 加藤 純郎 秋葉 貴光

出版者

一般社団法人 日本機械学会

雑誌

年次大会 2020 (ISSN:24242667)

巻号頁・発行日

pp.S05406, 2020 (Released:2021-03-25)

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Impingement jets are often used for cooling and heating of a surface or a body because a high heat transfer coefficient is obtained near the stagnation point of an impingement surface. For example, they are used for drying paper and fabrics, cooling gas turbine blades and electronic components(1). Recently, the usage of impingement jets can be predicted to be used in comparatively small spaces due to the miniaturization of devices. In these cases, the nozzle diameter, the flow rate, and the distance between the nozzle and the impingement plate are inevitably small.The purpose of this study is to clarify the flow and heat transfer characteristics when an impingement jet is applied in a narrow space. And now, when the heat transfer coefficients are measured by using the thin heated surface, a heat loss (qe) occurs in the in-plane direction of the heated surface due to heat conduction. Generally, this heat loss is often ignored at high Reynolds number (Re) and large diameter, because it is very small compared to the heat taken by the impingement jet. However, it may not be negligible in the case of a low Reynolds number and small diameter, because the heat taken by the impingement jet become relatively small.In this research, heat transfer characteristics using a circular impinging jet, which impinge on the heated plate, were investigated experimentally. The jet holes with the diameters D of 1, 3 and 5 mm were used. The values of H/D were from 2 to 6, where H is the distance between the nozzle exit and the impingement plate. The experiments were performed with the relatively low Reynolds number range of 250 ~ 2500. The surface temperature of the impingement plate was measured using an infrared camera, from which a heat loss (qe) in the in-plane direction and heat transfer coefficients were obtained. And the flow behavior of the jet was visualized by using a Laser Light Sheet(LLS)method. From the experiments, it was found that a heat loss (qe) needs to be considered in the case of a low Reynolds number and a small diameter.

著者

福垣 敦男

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.100, no.938, pp.23-27, 1997-01-05 (Released:2017-06-21)

著者

宇野 唯男

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.66, no.531, pp.569-577, 1963-04-05 (Released:2017-06-21)

著者

内山 寛信 櫛谷 義治 楠見 昌隆

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.612, pp.2731-2738, 1997-08-25 (Released:2008-02-26)

参考文献数

6

被引用文献数

1

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As one of the manufacturing processes in the apparel industry, a fabric roll has to spread a piece of cloth smoothly on the working table in order to cut the cloth into parts. In this process, it is important to prevent creasing by adjusting the spreading speed of the cloth. However, the construction of a speed control system is difficult, because the tension acting on the spread cloth cannot be estimated. Accordingly, the shape of a hanging cloth-belt in the cloth spreading machine is determined by a estimated curve based on the catenary function. The coefficients of the curve are calculated by detecting the displacement of a representative point on the doth-belt. Using this estimated curve. the tension can be measured with a high accuracy without touching the cloth. In this paper. the accuracy of the calculated values by the estimated cloth curve and the dynamic behavior of the cloth-belt are discussed. A new speed control system with the estimation mechanism of tension was proposed, and good performance was confirmed.

著者

森田 直樹 堀江 正信 須藤 海

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.86, no.882, pp.19-00337, 2020 (Released:2020-02-25)

参考文献数

22

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In numerical analyses based on unstructured meshes represented by the finite element method, quadrilateral and hexa-hedral meshes are used for a two-dimensional and a three-dimensional analyses, respectively, from the viewpoint of calculation accuracy and computation time. However, a method for automatically generating quadrilateral and hexahedral meshes has not been established thus far; in addition, a considerable amount of effort is required to perform manual mesh modifications. Mesh generation based on the frame field method is an effective technique to extract high quality quadrilateral and hexahedral meshes through the optimization of the posture of a frame with rotational symmetry. This method needs to solve a mixed-integer programming (MIP) problem while extracting the quadrilateral and hexahedral mesh using integer grid maps. When solving an MIP using a greedy method, solving a simultaneous equation is required approximately O(M) times, where M is the number of integer constraints. In this study, we propose a method to obtain a quadrilateral mesh by solving a simultaneous equation approximately O(1) times. In this method, the frame field is calculated using finite element discretization, and the finite element mesh is appropriately remeshed to be aligned with the integer grid resulting from the frame field optimization. The proposed method can reduce the amount of computation required to obtain integer grid maps for mesh extraction, without impairing the mesh quality. The proposed method is evaluated with respect to by mesh quality using the aspect ratio and the scaled Jacobian. Numerical examples demonstrate that the mesh quality is comparable to or better than that produced by conventional methods and manual procedures.

著者

益田 快理 Le Van Lich 嶋田 隆広 北村 隆行

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.85, no.876, pp.19-00175, 2019 (Released:2019-08-25)

参考文献数

26

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Ferroelectric behavior in mechanically strained SrTiO3 nanoporous is investigated using phase-field models. We find, in the paraelectric nanoporous, periodically arrayed ferroelectric nano-region is formed due to strain concentration, namely, polarization vortices emerge around each pore. Each ferroelectric region expands and connects each other with increasing strain, and ferroelectric network is finally formed. Since these ferroelectric regions can be regarded as a periodically arrayed ferroelectric nanomaterial embedded in a paraelectric material, this result means that periodically arrayed ferroelectric nanostructure, which may lead to novel functionalities, can be tailored through mechanical load. In addition, we find that the variation of load changes the geometrical characteristics of the ferroelectric structure such as shape and direction. Our finding provides a new concept to engineer future ferroelectric nanodevices by giving a new role to mechanical load.

著者

梅谷 智弘 的場 瞳 榎本 佐知子 陸 鳴宇 北村 達也

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 2022 (ISSN:24243124)

巻号頁・発行日

pp.1P1-Q01, 2022 (Released:2022-12-25)

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This paper describes a rapid development of a support robot system for a librarian service desk using a tabletop communication robot. It is important issues that the remote operation of the librarian service desk for the convenience of the visitors and the efficiency of the librarians. We developed a robot system that interacts with high accuracy and low latency in a short period of time using a cloud service for speech recognition and synthesis functions. We conducted participant experiments for tasks for the librarian service desk to evaluate the developed robot system. Experimental results showed the feasibility of the developed systems.

著者

山根 清美 湯浅 皓太 伊藤 孝起 小砂 匡 竹村 幾史

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.88, no.916, pp.22-00198, 2022 (Released:2022-12-25)

参考文献数

10

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We propose a method for solving differential equations implicitly using iterative calculations in spreadsheet software. This method uses difference equations by discretizing the coordinates of the independent variables with cells of spreadsheet for analysis. Thus, the equations are embedded in the cells performing substitution of grid point. In addition, the embedded equations are solved by Newton’s method, and the iterative function of the spreadsheet software is used in the calculation. This method can be applied even when the differential equation is discretized by an implicit solution method. Therefore, it can be applied to ordinary and partial differential equations of different types. The advantages of discretization using the implicit method (high computational accuracy, large time increments) are also presented in this paper. The analysis procedure is almost the same regardless of the type of equation. In this paper, as an example, a simple differential equation was analyzed using Microsoft Excel, a typical spreadsheet software, to illustrate the method. The results are also shown by the analysis of the gas lubrication equation.

著者

清弘 智昭 渡邊 伸悟 幸田 道友

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 2000 (ISSN:24243124)

巻号頁・発行日

pp.64, 2000 (Released:2017-06-19)

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鞠やリング, 升などを回転する傘の上で回す傘回しは日本の伝統芸能の1つである。この傘回しをおこなうロボットの制御はすでにPID制御で実現可能となったがその理論的な解析は行われていなかった。ここでは鞠の空間的な位置によるポテンシャルエネルギーと鞠の回転による運動エネルギに着目して数学モデルを作成した。さらに, このモデルに基づき現代制御理論による制御のシミュレーション, 及び実機による実験を行った。

著者

神原 早紀 Liliana Villamar Gómez 三浦 純

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 2022 (ISSN:24243124)

巻号頁・発行日

pp.1A1-T04, 2022 (Released:2022-12-25)

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Knowledge and contextual reasoning are essential to provide more efficient service robots that take into account diverse and continuously changing environments. In addition, since robots come into contact with humans, they need to have skills such as interactivity and language skills. In this paper, we propose a system for service robots that combines ontological knowledge reasoning and human-robot interaction to interpret natural language commands and successfully perform household tasks such as finding and delivering objects. We also apply this system to a real robot and verify its operation with commands that receive missing or unclear information, and clarify problems that occur in the real world.

著者

渡邊 大賀 松村 昌典

出版者

一般社団法人 日本機械学会

雑誌

流体工学部門講演会講演論文集 2021 (ISSN:24242896)

巻号頁・発行日

pp.OS03-03, 2021 (Released:2022-06-25)

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Three-dimensional structures such as longitudinal vortex appear in the two-dimensional vortex street wake of a cylinder. These structures are very complex structures. It is important to understand the details of the three-dimensional structures in the two-dimensional vortex street wake. The purpose of this study is to construct the three-dimensional structures from layered cross-sectional images and to understand its structures. In the flow visualization, four cylinders with different diameter were used to change the Reynolds number. The 3D structure constructed in this study could be observed from any angles and the details of its structures were revealed.

著者

田中 宗信 佐藤 忠教 阿川 薫

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.52, no.484, pp.4084-4093, 1986-12-25 (Released:2008-03-28)

参考文献数

5

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An experimental study on the reforming characteristics of five different catalysts for methanol fuel was conducted and the endurance of each catalyst was examined using a fixed type reformer. A reformer utilizing the heat of exhaust gas was also designed and constructed, and the effect of blending the reformed methanol fuel to gasoline was studied in the combustion process of a spark ignition engine. Analyses of the indicator diagram show that the increase of the ratio of reformed gas and gasoline results in (1) an increase of speed and stability of combustion characteristics, (2)the extension of the lean limit of the air-fuel ratio, (3) an increase in the thermal efficiency, (4) a decrease in the cycle-by-cycle fluctuation of the combustion process, and (5) quick achievement of stability for abrupt changes in the throttle position. In view of three results, the optimum operating conditions are proposed.

著者

宋 載翼 吉田 正武 小栗 康文 五味 努

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.54, no.508, pp.3572-3578, 1988-12-25 (Released:2008-03-28)

参考文献数

13

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It has been reported in many papers that the humidity in a mixture causes a lower S. I. engine output because of the decrease of combustion heat and flame speed. However, the reason for and the extent of the above-mentioned effect have not yet been elucidated. In order to clarify the effect of humidity on S. I. engine output, the author applied the relationship between the humidity and combustion period to the analytical model of an S. I. engine which formulates the work done on a piston as a function of ignition timing. The result shows that (1) humidity decreases S. I. engine output by about 4.5% at constant spark advance, but at optimum spark advance the reduction is about 1.2%, and (2) the rate of flame speed reduction as a result of humidity in a engine is the same as the rate in burner.

著者

アハマドアティフ モハマドファウジ 鈴森 康一 大賀 淳一郎 後藤 達彦

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-L06, 2017 (Released:2017-11-25)

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This paper presents the intrinsic muscles of a Human-like Robotic Hand (HR-Hand), with a focus on dorsal interossei and palmar interossei muscles. Three links of palmar and four links of dorsal interossei muscles were fabricated according to human hand anatomy using 1.3 mm thin McKibben actuators. The experimental result using single index finger shows that the robotic hand could achieve palmar adduction and dorsal abduction and assist in flexion of fingers that imitate the actual function in the human hand.

著者

平岡 幸三

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.83, no.736, pp.319-322, 1980-03-05 (Released:2017-06-21)

著者

石川 拓実 山崎 洋一 村山 龍太郎

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 2020 (ISSN:24243124)

巻号頁・発行日

pp.1P2-E15, 2020 (Released:2020-11-25)

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Atmosphere estimation system for family-type robot in living space is proposed to realize smart symbiotic space, where a three-dimensional atmosphere (atomosfield) is calculated based on multiple human emotions recognized from webcam video. The system is implemented with OpenCV and Dlib for face and emotion recognition, and tested for webcam arrangement. As a result of the experiment for thee human and two LOVOTs interaction in the living space, the proposed system has shown the highest detection of times of 380 at the level of 0.45[m] from the floor and the front (0 deg) of the users in face recognition. The proposed atmosphere estimation realizes casual and delicate support service for people in smart living environment.