著者

金子 康智 岸本 星太 森 一石 大山 宏治

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.861, pp.17-00447-17-00447, 2018 (Released:2018-05-25)

参考文献数

13

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Although, in designing blades, it is assumed that all blades on a disk are identical (tuned system), the vibration characteristics of the blade is slightly different due to the manufacturing tolerance, the deviation of the material property, and so on (mistuned system). As a result, in the forced response of an actual bladed disk caused by the flow distortion, the responses of all the blades on a disk become different, and the response of a certain blade may become extremely large, due to the split of the duplicated natural frequencies, the distortion of the vibration modes, and so on. On the other hand, it is suggested by many researchers that the mistuning suppresses the blade flutter, because the complete travelling wave mode is not formed in a disk. In other words, the effect of the mistuning acts on the dangerous side for the forced vibration, while on the safety side for the blade flutter. In this study, the stability analysis and the frequency response analysis of mistuned bladed disks are carried out using the reduced model with high fidelity, in order to research the vibration characteristics of typical mistuned bladed disks. Based on the analysis results, an optimal design procedure of mistuned bladed disks considering both the forced response and the self-excited vibration is proposed.

著者

田中 椋也 涌井 伸二

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.84, no.861, pp.17-00424-17-00424, 2018 (Released:2018-05-25)

参考文献数

10

被引用文献数

3

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This paper considers the implementation of a cascade type PIS compensator for the pneumatic anti-vibration apparatuses (AVA) control system. In precedence research the parallel type PIS compensator was used. This is composed of a PI and S compensators connected in parallel. However a PIS compensator is interpreted as a special case of what is used in repetitive control. In this case, a cascade connected compensators is used. According to this, the PIS compensator should be in series type. Also, parallel type PIS compensator generates swing of the output signal. Through above problems, cascade type PIS compensator is considered. However, the AVA control system with the compensator causes collision and steady-state deviation. In order to resolve these problems, we improve the structure of the compensator and its switching method. This experimental result shows that the normal operation of the AVA control system with cascade type PIS compensator. From the above, we show that the implementation of cascade type PIS compensator for the AVA control system.

著者

加藤 潤也 藪井 将太 高木 賢太郎 井上 剛志

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.861, pp.17-00227-17-00227, 2018 (Released:2018-05-25)

参考文献数

20

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In design of rotating machines, analysis of external force is important for stable rotating operation. The various external forces such as unbalance force, seal contact force and rotor dynamic fluid force effect on the rotor system, dynamic characteristics of rotating system is changed by the external forces. The external force can vary depending on a rotor trajectory. In previous studies, a mathematical model of the dynamic characteristics had been formulated for small amplitude orbit around the equilibrium point for the rotor trajectory. However, the formulation hasn't been yet established in the rotor trajectory with large amplitude or eccentricity caused by the external forces. In this study, an experimental system using active magnetic bearing (AMB) is developed to achieve the formulation. The system can generate any arbitrary trajectory assuming various external forces and the rotor system follow the generated trajectory. The system can estimate the external force at the same time. Current flowing through coil of the AMB is controlled by a controller designed based on the frequency response to follow the arbitrary orbit. Then, the external forces are estimated from the control signal by the disturbance observer. Experiments were performed by assuming unbalance forces generated in the elastic rotor. From the results it was confirmed experimentally that high precision tracking control and estimation of external force are possible. The various rotor trajectory under the action of the external forces can be repeated by using the system, and the external force can be analyzed by the experimental data.

著者

藤井 文武 椎木 健裕 澁谷 景子 樫部 直人 丸山 章

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.84, no.861, pp.17-00495-17-00495, 2018 (Released:2018-05-25)

参考文献数

8

被引用文献数

1

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This paper proposes an algorithm to generate the augmented reference position trajectory for the realtime 3D robotic phantom system which is used in the quality assurance of the radiation therapy. Quality assuarance is the important clinical part of the radiation therapy which ensures the delivery of the prescribed dose to the tumor of the patient. High precision quality assurance can be a difficult task if the tumor exhibits respiratory induced motion inside the body of the patient, as the motion fluctuates along with time and it suffers large inter-patient difference. This paper presents several algorithms to modify and/or correct the reference tumor trajectory of the patient and generate the augmented reference trajectory sequence for the already existing and tuned control system of the robot manipulator to yield high precision tracking to the original tumor motion trajectory. Experimental validation has been carried out for four lung tumor trajectories in the clinical environment using equipments used in the radiotherapy treatment and it has been shown that the clinical demand on the precision of tumor motion tracking has been satisfied for all the four cases.

著者

早場 亮一 田邊 由紀子 米澤 隆行 梅田 純子 近藤 勝義

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.84, no.861, pp.17-00491-17-00491, 2018 (Released:2018-05-25)

参考文献数

30

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Stents are one of devices for the invasive cardiac catheterization (Percutaneous Transluminal Coronary Angioplasty) and especially for pediatric catheterization, the stent is manufactured by superelastic alloys including TiNi alloy. Transradial coronary intervention (TRI) is an invasive treatment in comparison with transfemoral coronary intervention (TFI), as TRI can reduce the risk of bleeding complications. To perform TRI, it is necessary to reduce the thickness of stent and diameters of delivery system. Therefore, one of the solution is to improve the strength of the materials for the stent. In this study, the medical application to stents was investigated by manufacturing high-strengthened Ni-rich powder metallurgy TiNi alloy using pure Ti powder and pure Ti pre-mixed powder. Ni-rich TiNi shape memory alloys showed much high plateau stress and enough shape recovery rate compared to the conventional ingot metallurgy TiNi alloy used in the commercial stent devices. In the simulation of the stent radial force by a finite element analysis (FEA), it was clarified that the radial forces of Ti-52.0 at.%Ni (stent wall thickness; 80 μm) and Ti-50.5 at.%Ni (stent wall thickness; 200 μm) were equivalent. The improvement of plateau stress of TiNi alloys successfully reduced the thickness of the stent by 120 μm (60 %). In fact, the stent using Ni-rich TiNi alloy resulted in the thinned stent with a high radial expansion force. When implanting the stents made of Ni-rich TiNi alloy into the external iliac artery of pigs, no stent fracture was observed, and in-stent occlusion never occurred after 1-month and 3-month placement of the stents. They are similar biocompatibility to commercial stents because of the similar results of inflammation.

著者

大久保 光 前田 寛陽 川田 将平 田所 千治 佐々木 信也

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.84, no.861, pp.17-00564-17-00564, 2018 (Released:2018-05-25)

参考文献数

22

被引用文献数

1

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The wear acceleration mechanism of a DLC film lubricated with MoDTC solution was investigated by using in-situ and ex-situ analytical techniques: Raman spectroscopy, SEM-EDS, ToF-SIMS, and nano-indenter. From the results, the structural change of the DLC film strongly related to the formation of Mo-carbide containing tribofilms, which were much harder than DLC used in this study. Therefore, the MoDTC-induced wear acceleration of the DLC film is caused by hard Mo-carbide containing tribofilms on a counter-face steel surface.

著者

瓜生 耕一郎 村上 隆則 中村 守正 射場 大輔 船本 雅巳 森脇 一郎

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.84, no.861, pp.17-00536-17-00536, 2018 (Released:2018-05-25)

参考文献数

6

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The high productivity of gear skiving has caused the process to attract a lot of attention in recent years and taper shaped skiving cutters are generally used in current gear skiving. A cutter axis in gear skiving is inclined to a gear axis and a taper shaped skiving cutter could cause tooth profile deviations of skived gears after re-sharpening of tool faces. Adjusting cutter position and/or re-profiling of cutter flanks are applied to enable tooth profile deviations of skived gears to remain within acceptable ranges when the adjustment is necessary. Adjusting cutter position is preferred to re-profiling of cutter flanks due to desire for low production cost. However, the universality of the current methods of calculating cutter positions is still not confirmed. The present study explains that the current methods for obtaining cutter positions could require individual calculating formulas according to cutter specifications for each particular gear. A universal method which avoids such complexity of making various formulas could contribute to permit gear skiving to become more useful in the gear machining field. Then such a desirable method is proposed and the reasonability of the method is confirmed by experiments. In addition, this study discusses the existence of scope in which the method can be applied and a method for checking collisions between cutter flanks and gear tooth flanks being cut after adjustment of cutter position.

著者

吉桑 義雄 米谷 晴之 宮本 佳典 亀山 正樹 出口 学 水谷 敏彦

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

vol.84, no.861, pp.17-00450-17-00450, 2018 (Released:2018-05-25)

参考文献数

15

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Motors are used in many appliances, and noise reduction is strongly demanded. One of the main causes of noise is electromagnetic excitation force and it is well known that the excitation force is increased by the eccentricity of the rotor to the stator. For this reason, it is very important to decrease the eccentricity, but there are limits because the eccentricity is due to inevitable manufacturing tolerances or assembly errors. So, we propose a method to estimate the eccentricity of the motors in the process of manufacturing by using windings as a sensor. When the rotor and the stator are in an eccentric condition, the impedance of each winding is different. We developed an experimental apparatus that can set the amount of eccentricity and verified that the terminal voltage of each winding changes proportionally to the eccentricity. In order to produce motors with eccentricity of almost zero, we need to estimate the two-dimensional amount of eccentricity in a very short time. When the number of turns of each winding is different, there is interaction between each winding and so the accuracy of the estimation decreases. To solve these problem, we applied a different frequency of voltage to the winding located on the x axis and the winding located on the y axis, so that we can estimate the amount of eccentricity for the x direction and the y direction with high accuracy at the same time. We also developed a way to produce motors by using this technology. After detecting the terminal voltage of each winding under the tentative assembly situation, we adjust the amount of eccentricity to almost zero and fix the motor by laser welding. As a result, we were able to mass produce motors with eccentricity of under one micrometer and with a very low noise level.

著者

宮本 孟宜 横山 博史 飯田 明由

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.84, no.861, pp.18-00121-18-00121, 2018 (Released:2018-05-25)

参考文献数

19

被引用文献数

1

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Intense sound is radiated due to aeroacoustic feedback loop from a flow around the trailing edge of a curved plate with a kink shape such as a bonnet of an automobile. For the reduction of this noise, the control by a plasma actuator (PA) was investigated. The aim of this investigation is to clarify the effects of flow control by the PA on noise reduction and the noise reduction mechanism. To do this, wind tunnel experiments with a half-scale bonnet model and direct numerical simulations of flow and sound fields were performed. The investigation of the effects of the position for the installation of the PA on the control presents that the control at the position close to the flow separation point around the kink is effective for the noise reduction. Also, the control effects were compared between co-flow and counter-flow configurations regarding the direction of the mean induced flow by the actuator to the freestream. The mean velocity profiles showed that the flow separation was suppressed by the control with both configurations, while this control effect is more effective for the counter-flow configuration. The measured velocity fluctuations present that the power in broadband frequency range in the downstream of the actuator becomes larger by the control with both configurations. The predicted results show that small-scale vortices are shed near the wall around the actuator due to the large counter-flow induced flow. This introduction of the vortices and the intensification of the broadband velocity fluctuations lead to the suppression of the flow separation. Also, the development of the power of the velocity fluctuations at the fundamental frequency of the baseline tonal sound is weakened by the suppression of the flow separation. This supports the predicted results of the suppression of the two-dimensional vortices contributing to the acoustic radiation around the re-attachment point by the control. Consequently, the control can lead to the suppression of the feedback loop of the radiating mechanism of tonal sound.

著者

吉村 一樹 保坂 知幸 安川 義人 石井 英二 小倉 清隆 澤田 恵介

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.861, pp.18-00068-18-00068, 2018 (Released:2018-05-25)

参考文献数

19

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Reduction of particulate matter (PM) in exhaust gas from automobile engines is in high demand. Fuel stuck on the engine wall causes incomplete combustion, and generates a large amount of PM. To prevent this, shape of fuel injection spray must be controlled with precision. We focused on the valve offset of the injector as a factor influencing the spray shape. Computational analysis was conducted to investigate the effects of the valve offset on inner nozzle flow and spray shape (spray direction and liquid penetration). Simulated spray behavior image, footprint, and liquid penetration agreed well with experimental results. From the inner nozzle flow simulation results with the valve offset, it was found that fuel tends to flow in the direction of the valve offset near a sac in the nozzle to provide the fuel to the holes. This flow was caused by the smaller flow path fomed in the valve offset direction. From the spray simulation results, shifts in the spray direction of the plumes were caused by the flows near the sac. Some plumes were injected in the direction opposite to the valve offset. The holes with larger drill angle located in the valve offset direction, and larger valve offset caused larger changes of spray directions. Furthermore, liquid penetration was investigated. We showed that the flow separation in the holes caused by the valve offset affects the velocity distribution at the hole outlet and results in changes of the penetration length when the drill angle is small. It was found that the valve offset causes the change in the inner nozzle flow, and results in the change of the spray shape. We concluded that the correlation of nozzle geometry and valve offset is important for controlling the spray shape.

著者

今村 信昭 吉成 聡志 金子 真

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.564, pp.2395-2400, 1993-08-25 (Released:2008-02-26)

参考文献数

14

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A simple torque sensor for a tendon-driven manipulator is proposed. The finger joint torque around a drive pulley is proportional to the tension difference on both ends of the pulley. With a coupling mechanism between tendons, this tension difference can be measured directly without detecting individual tendon tensions. The tension differential-type torque (T.D.T.) sensor is based on this idea and is useful for compensating for friction existing in the transmission system of the manipulator. However, so far, the T.D.T. sensor needs at least one tension pulley to support a driving tendon. This paper shows that it is possible to design a T.D.T. sensor without any tension pulley maintaing its basic principle. A torque sensor installation on the movable link makes it possible to eliminate the tension pulley and downsize it.

著者

章国 光 古荘 純次

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.592, pp.4687-4695, 1995-12-25 (Released:2008-02-26)

参考文献数

11

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Friction in joint driving systems constitutes an important source of nonlinearity that makes it difficult to achieve high-precision control. In this paper, a method of estimating friction is proposed, which requires a joint torque signal, armature current and motor angular velocity. Considering disturbance rejection, a position control method is proposed as follows. Vibration is restrained by bandpass joint torque feedback, and high-precision position control is realized by friction feedforward compensation. Assignment of pole distribution is employed to determine three control coefficients, and the effect of disturbance rejection is compared and evaluated for three kinds of pole distributions. Properties of the proposed control are discussed, and experimental results are also Presented.

著者

MIYOSHI Yoshikazu AOKI Hiroko OGAWA Masato

出版者

一般社団法人 日本機械学会

雑誌

The Proceedings of the JSME international conference on motion and power transmissions

巻号頁・発行日

vol.2017, pp.8-2, 2017

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<p>Planetary gear set has multi planetary pinions between sun gear and ring gear, and it meshes at the several points simultaneously. Therefore, it is difficult to predict the mesh excitation force of the entire planetary gear set, and it is very difficult to design vibration and noise performance.<br>This paper proposes a design method that focused on the mechanism of the mesh excitation force about the planetary gear set. This method designs the optimum specification by analyzing the vibration behavior and the mesh excitation force.<br>As practical applications, the optimum specification is determined by analyzing the mesh excitation force of a sequentially phased (SP) planetary gear set and an in-phase (IP) planetary gear set, and considering the vibration mode in focused frequency. As a result, this method is verified by actual transmission tests, the gear noise is improved by changing the gear specification that contains different mesh phasing.</p>

著者

松島 脩平 原田 宏幸

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.1P2-H12, 2017 (Released:2017-11-25)

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3D printers are becoming popular and using in many scenes. They enable to make products simply and rapidly according to the design models. However, they can make only a single bulk parts at a time in general. If we can make a whole robot structure at once by 3d printer, it became possible to manufacture a desired robot on the spot in a minute. In this report, we propose a method for making a robot structure including joints at one time by a Fused Deposition Modeling (FDM) type 3D printer. It is unnecessary to assemble after printing. Further, we produced a wire-driven quadruped walking robot as an example of the proposed method.

著者

福田 聡 中島 求

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会関東支部総会講演会講演論文集 2017.23 (ISSN:24242691)

巻号頁・発行日

pp.1616, 2017 (Released:2017-06-19)

著者

只野 快 末岡 浩治

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.858, pp.17-00542-17-00542, 2018 (Released:2018-02-25)

参考文献数

24

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To apply the germanium (Ge) thin film for various electronic devices, energy band structure should be controlled by carbon (C) and/or Tin (Sn) doping. It is important to understand the stable atomic configurations of C and Sn atoms near the (001) surface of a Ge thin film. In this study, first principles calculation based on density functional theory was performed to obtain the formation energies and the thermal equilibrium concentrations of C and Sn atoms near the surface of Ge thin film. The results of the analysis are threefold. First, C and Sn atoms are most stable at the first atomic layer of the Ge thin film, and the surface does not affect the stability of C or Sn atoms deeper than the fifth layer. Second, C and Sn atoms at the second to fourth layer increase the thermal equilibrium concentration of newly arrived C and Sn atoms at the surface during film growth. Third, in the case of mono-doping, formation energy of C (Sn) at the (001) surface increases with increasing concentration of surface C (Sn). In the case of co-doping at C/Sn concentration ratio of 1:1, the increases of formation energies are suppressed in comparison to the case of mono-doping. It is concluded from these results that co-doping enhances the incorporation of C and Sn atoms in the Ge thin film. Furthermore, the doped atom near Si surface becomes more stable than that in the Si bulk, and it is more remarkable in comparison to Ge.

著者

滝田 好宏 ブイクワン ズン 伊達 央

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.781, pp.3278-3289, 2011 (Released:2011-09-25)

参考文献数

18

被引用文献数

1 1

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This paper proposes SSM(Sensor Steering Mechanism) for a lateral guided vehicle with an articulated body which has an arbitrary position of articulation joint. The last paper shows the SSM for an articulated vehicle with a bending joint located at the center of its wheel base. The articulated robotic vehicle with SSM is demonstrated an accurate line following at low speed and a drift cornering at high speed moving. This paper discuses the SSM for the arbitrary position of articulated joint and the simple relation is derived for the lateral guided method for the articulated vehicle. In order to demonstrated the advantage of this method, an experimental vehicle is developed and tested on the evaluation course which is used previous papers. Dynamical simulations of experimental vehicle are preformed and the data is compared with the experimental data. These results demonstrate that a SSM for articulated vehicles achieve at high speeds and maintain stability on a test course.

著者

中山 展空 下田 昌利

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.84, no.858, pp.17-00484-17-00484, 2018 (Released:2018-02-25)

参考文献数

29

被引用文献数

3

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In this paper, we present a simultaneous optimization method of shape and topology for designing a light-weight plate and shell structure. The free-form optimization method for shells and SIMP method are respectively employed for shape and topology optimization, and combined effectively. Shape and fictitious homogenized-density variations are used as the design variables, and simultaneously determined in one iteration of the convergence process. With this method, the optimal topology is determined in the variable design surface optimized by shape optimization. Compliance is used as the objective functional, and minimized under the volume constraint. The optimal design problem is formulated as a distributed-parameter optimization problem, and the sensitivity functions with respect to shape and density variations are theoretically derived. Both the optimal shape and density variations are determined by the H1 gradient method, where the sensitivity functions are applied as the Robin condition to the design surface. With the proposed method, the optimal lighter and stiffer shell structure with smooth surface can be obtained without any design parameterization and numerical instabilities such as checkerboard and zigzag-shape problems.

著者

廣明 慶一 渡辺 昌宏

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.84, no.858, pp.17-00416-17-00416, 2018 (Released:2018-02-25)

参考文献数

23

被引用文献数

1

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An instability mechanism of flutter generated on a rectangular flexible sheet in an axial fluid flow is investigated through the energy-transfer quantifications. The work done by unsteady fluid force acting on the fluttering sheet surface is calculated based on a three dimensional flutter analysis utilized the Doublet-point method and finite element method. Then the work done by fluid force is divided to three terms caused by fluid added mass, damping and stiffness by applying Roger's approximation, and influence of each term on stability is clarified. As a result, it is clarified that the work caused by fluid added stiffness is dominant for excitation of flutter. Lastly, the influence of the work caused by interaction of natural vibration modes of the sheet which are dominant for flutter on stability is investigated, and the instability mechanism of flutter is discussed.

著者

松野 隆幸 西田 祐也 米森 健太 李 想 向田 直樹 加藤 直輝 Myo MYINT 山田 大喜 Nwe Lwin KHIN 見浪 護

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.84, no.858, pp.17-00242-17-00242, 2018 (Released:2018-02-25)

参考文献数

24

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A variety of robots has been studied and developed for undersea exploration. One of the applications for undersea exploration is mining of undersea resources such as methane hydrate and rare metal by Autonomous Underwater Vehicle (AUV). To extend active duration time of the robot in the sea, a system through which the AUVs recharge autonomously batteries is a key technology. Our reseach group has confirmed in a pool environment the dual-eye visual servoing system made a pole attached to the vehicle dock into a hole. This experiment simulates situation where the vehicle approaches recharging station under deep sea. But previous studies were conducted with ROV (Remotely Operated Vehicle) that is controlled by remote computer instead of human operator. In those experiments, power cables affected performance of control accuracy. Therefore the performance of visual feedback with AUV named Tuna-Sand2 that is compeletely indepent from cables or wires and has a general structure of modernized AUV system, has been verified to confirm the practicability of dual-eye dockig system.