著者

古森 健吾 戸井 武司

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.84, no.862, pp.18-00103, 2018 (Released:2018-06-25)

参考文献数

8

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Numerical simulations, such as the finite element method have been widely used to predict noise and vibration behavior. This allows reducing the development time and production cost of products. However, these results have been calculated based on the governing equations at each physical areas as the idealized conditions. Then, these simulations are not taken into account the fluctuation of response characteristic by the uncertainties of noise factors. Therefore, it is important to restrain the fluctuation of products properties by the uncertainties. In this paper, focusing on the transient analysis, we propose a robust design for minimizing the time history amplitude fluctuation by structure uncertainties. The robust design is implemented based on the combined use of the stochastic finite element method and the structural optimization. Since this method is performed by minimizing the 1st sensitivity, we will formulate the 1st and 2nd sensitivity in the time domain. Then, the proposed method is validated by applying it to the simple mass-damper-spring system whether the fluctuation of the time history response amplitude is restrained.

著者

平光 立拓 難波江 裕之 鈴森 康一 遠藤 玄

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.862, pp.18-00083, 2018 (Released:2018-06-25)

参考文献数

10

被引用文献数

1

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Pneumatic artificial muscles have many advantages. They have high force mass ratio, high compliance and simple structures. Especially, the flexibility contributes to compose novel mechanisms. The flexibility of pneumatic artificial muscles releases us from the spatially strict design required for rigid mechanical elements: it could actualize compact mechanisms made of a fewer parts. Our research group developed a thin McKibben actuator. The thin McKibben actuators is more flexible than conventional McKibben actuators. Authors succeeded in manufacturing novel soft mechanisms that are made of only braided artificial muscles. We aim to establish a design method for these novel mechanisms. We already have fabricated a cylindrical mechanism made of helical muscles. In this paper, we report a geometric model for the cylindrical mechanism. We focus on only deformation of a side surface in the coordinate system of muscles to simulate the movements of the cylindrical mechanism. The movement was verified by an experiment, and besides, it was simulated successfully in the geometric model that was created. The deformation of height and radius directions changed according to muscles alignment.

著者

河内 毅 栗山 幸久 鈴木 克幸

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.862, pp.18-00063, 2018 (Released:2018-06-25)

参考文献数

11

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In order to clarify the mechanism of the vehicle body hysteresis affecting “rigidity feeling”, one of the driver's sensory evaluation in the driving test, the influence of friction acting on spot welding flanges on hysteresis, which is drawn by the displacement-load diagram of double-hat-shaped parts assembled by spot welding under static or relatively slow deformation, is experimentally and numerically evaluated. The hysteresis of two specimens, one has the contact around R-tangent of flanges and the other has it around edge, are compared and it is confirmed that the former type has larger hysteresis than the latter. The hysteresis is evaluated by the friction loss which is energy dissipation generated only by friction on the surfaces of the spot welding flanges. The loss calculated by the finite-element-method (FEM) with the contact and friction between two flange surfaces opposing each other has good agreement with that measured by the experiment. Additionally, by studying the detail of the relative slip and friction force distribution on the surface of two flanges obtained by the FEM analyses, the difference in hysteresis of two specimens and the cause of the friction loss are discussed.

著者

田中 皓一 高木 至人

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 B編 (ISSN:03875016)

巻号頁・発行日

vol.58, no.551, pp.2114-2118, 1992-07-25 (Released:2008-03-28)

参考文献数

3

被引用文献数

1 3

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This paper reports the development of a sheet carrying mechanism by means of the progressive wavy motion of a thin elastic membrane which is sustained by magnetic fluid. The sheet carrier consists of a magnetic fluid layer in a shallow rectangular vessel, a thin elastic membrane covering the magnetic fluid, and digital electronic equipment to drive and control a series of magnetic coils. By applying the magnetic field in the form of sinusoidal waves, progressive wavy motions of the magnetic fluid and the elastic membrane are excited, and the sheets of paper or plastic film can be carried on the surface of the membrane. An interesting transportation behavior and its dependence on the wavelength and the frequency of the progessive waves are examined experimentally.

著者

根本 健也 山本 浩 成川 輝真

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.862, pp.18-00062, 2018 (Released:2018-06-25)

参考文献数

16

被引用文献数

1

---

One of effective ways to suppress vibration of a mechanical system is using a dynamic vibration absorber. The dynamic vibration absorber consists of a mass, a spring and a damper. The optimal tuning of natural frequency and damping ratio of the dynamic vibration absorber is required to suppress vibration, so adding an adjustable mechanism of stiffness and damping of the dynamic vibration absorber makes tuning easy. This paper proposes a new design concept of an adjustable dynamic vibration absorber consisted of an adjustable mechanism of stiffness and damping. The adjustable mechanism of stiffness consists of an arm, a couple of coil springs and a rotatable spring holder. Stiffness is varied by rotating the spring holder. The adjustable mechanism of stiffness can expand the range of stiffness by increasing spring constant of a couple of coil springs. The adjustable mechanism of damping consisted of a copper plate, a couple of magnets and a linkage mechanism. Damping is varied by driving the linkage. Driving the linkage to tune damping is necessary large torque because of attractive force of magnets. A compensation spring attached to the linkage can reduce the driving torque for tuning the damping. We made the proposed adjustable dynamic vibration absorber and verified whether the proposed adjustable mechanism is valid by experiments.

著者

古林 卓嗣

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.66, no.641, pp.306-313, 2000-01-25 (Released:2008-02-26)

参考文献数

12

被引用文献数

1 1

---

A numerical study of self-acting gas-lubricated wave journal bearings is presented for their dynamic performances : HFW(self-excited half-frequency whirl)stability and dynamic response of an out-of-balance rotor. The study is conducted under practical operating conditions by means of a nonlinear orbit approach. Numerical examples of wave bearings are compared with those of herringbone-grooved bearings, and it is found that wave bearings give relatively favorable dynamic performances. Considering both HFW stability and dynamic stiffness, three-wave bearings are recommended for a practical use. However, it should be pointed out that HFW stability of wave bearings is quite sensitive to the wave amplitude, and also the synchronous orbit geometry of an unbalanced rotor supported on a wave bearing can be complicated out of plain circle.

著者

古林 卓嗣

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.62, no.604, pp.4636-4643, 1996-12-25 (Released:2008-02-26)

参考文献数

20

被引用文献数

1 1

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A multigrid method has been introduced as a fast alternative to conventional relaxation methods for obtaining a solution to the Reynolds equation for self-acting gas-lubricated bearings. This paper verifies the procedure applied to both static and time-dependent dynamic analyses of plain-cylindrical journal bearings. The method gives successful results with less computational effort compared with single grid-oriented iterative methods. In addition, the new approach does not require a trial and error process to optimize the overrelaxation parameter unlike a successive overrelaxation method. The nonlinear orbit method which is an accurate but time-consuming transient analysis is expected to be reduced to a handy design tool for a complicated bearing system on incorporating the multigrid technique.

著者

古林 卓嗣

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.65, no.629, pp.330-336, 1999-01-25 (Released:2008-02-26)

参考文献数

12

被引用文献数

1 1

---

Both experimental and numerical studies are conducted on half-frequency whirl (HFW) stability of axially-grooved self-acting gas-lubricated journal bearings. The studies demonstrate that 8-grooved bearings are unconditionally unstable with usual bearing clearance and rotational speed. On the other hand, 2 grooved bearings operate stably at relatively low values of bearing number which are obtained with usual clearance and speed. The physics of HFW stability is attributed to the pressure distribution geometry. Further, as a result of extensive numerical simulations, it is found that 3 grooved bearings with groove width ratio to total width of 0.3 through 0.5 give favorable stability performance.

著者

山口 大貴 園部 元康 日野 順市

出版者

一般社団法人 日本機械学会

雑誌

中国四国支部総会・講演会 講演論文集 2016.54 (ISSN:24242764)

巻号頁・発行日

pp._510-1_-_510-2_, 2016-02-26 (Released:2017-06-19)

著者

青木 ゆうい 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.862, pp.18-00052, 2018 (Released:2018-06-25)

参考文献数

11

被引用文献数

1

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In this paper, it is confirmed that natural frequency of isolated table is operated and that degeneration, which means that some natural frequencies have the same value, has a bad influence. Pneumatic anti vibration apparatuses (AVAs) support that loaded devices, i.e., XY stages, operate accurately. However, many strict design conditions are imposed on AVAs with six degrees-of-freedom (DOF) which are used on manufacturing floor. There is a risk that the natural frequency of each motion mode approaches, in other words, that isolated table falls into degeneration. This disturbs accurate operations of XY stages. In this paper, AVA with two DOF is used to simplify motion instead of six DOF. First, it is stated that mode control is used to pressure control. Next, position differential feedback (PFB) is proposed. PFB, which is used to the natural frequency control, is applied for each mode. This means that air spring stiffness is considered as each motion mode, and these are deleted or given. It is shown that the natural frequency of each mode can be controlled individually, by calculation, simulation, and experiment. Finally, the degeneration is reproduced to AVA with two DOF by PFB. At this moment, acceleration control which effects to nearby the natural frequency interferes with each other mode. From these results, conclusions are the following: degeneration should be avoided, and mode PFB is effective to control natural frequency of each motion mode. In addition, mode PFB accomplishes not only avoiding degeneration, but also lowering the natural frequency.

著者

髙木 山河 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.862, pp.18-00043, 2018 (Released:2018-06-25)

参考文献数

10

被引用文献数

1

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In the field of precision positioning such as semiconductor exposure apparatus, weak disturbance vibration from the floor influences processing accuracy. In recent years, as the precision of the device increases, the vibration allowance value becomes more severe, and performance improvement of the vibration isolator is required. In order to improve the performance, there are researchs reducing natural frequency by the frequency characteristics of the vibration transmissibility from the floor to the vibration isolator. Reducing natural frequency and decreasing stiffness are equivalent, and main target was stiffness generated by compressed air of air spring. In addition, rubber bellows of air spring is also targeted for further performance improvement. We already proposed a method combining the two stiffness separately decreasing method. However, decreasing stiffness simultaneously destabilized the device, then it could not be completely decreased. In this paper, as a new stabilization method, stiffness is completely decreased only in the operation frequency band. Since the low frequency has positive rigidity, the localization is maintained. We demonstrated the reducing natural frequency by the experimental result. When stiffness was completely decreased, the servo stiffness which had not been focused in the past became dominant in determining the natural frequency. Therefore, an appropriate design of the servo stiffness is required for further reducing natural frequency. To satisfy this requirement, we calculated the relationship between natural frequency and servo stiffness and gave an index for appropriate design.

著者

平岡 延章 十河 宏行 由良 諭 逸見 知弘 正箱 信一郎 石井 耕平 津守 伸宏 鹿間 共一 漆原 史朗 太良尾 浩生

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.862, pp.18-00031, 2018 (Released:2018-06-25)

参考文献数

6

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A motor shaft direct drive is known as a simple and low cost scheme for small toy vehicles, however the mechanism how it produces propelling force has not yet been explained nor discussed in detail. A trivial idea that a small dent is formed on the road surface just under the shaft end due to static weight takes us to the unexpected result. Brief calculus reveals that the propelling force vector of the system directs somewhat forward with respect to sagittal plane which includes motor shaft slant axis. It suggests that the motor alternative cw and/or ccw rotation generates gradual forward movement, i.e. the vehicle moves perpendicular direction with respect to that of right-left swinging motion. The forward motion is confirmed experimentally with single motor shaft direct drive vehicle, and also discussed in details.

著者

大平 峻 島田 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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.862, pp.18-00019, 2018 (Released:2018-06-25)

参考文献数

19

被引用文献数

1

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This study aims to realize fast disturbance estimation with a Kalman filter (KF). This paper presents a methodology of fast estimation and rejection for some types disturbances. This methodology attempts to estimate the state of mechatronics systems that rejected the influences of disturbance and noise by using KF. Most of known disturbance estimation method is the disturbance observer (DOB). However, the conventional DOB can not estimate the disturbance that is contaminated of noises. Generally, KF is known as state estimation algorithm that can consider influences of various noise. In addition, we had done some previous studies to design a linear KF with disturbance estimation. We obtained a fact that the disturbance estimation speed by the KF is slow from these studies results. Therefore, this paper proposes a new design method of KF with disturbance estimation which includes a design parameter to speed up disturbance estimation, where we have never concerned in this paper with KF design method except linear systems. Finally, we show the design method on the proposed method and usefulness via the simulation results relative to the position control for an simple cart system.

著者

山田 誉矩 鈴木 章太 川越 吉晃 米村 茂 山本 恭史

出版者

一般社団法人 日本機械学会

雑誌

東北支部総会・講演会 講演論文集 2017.52 (ISSN:24242713)

巻号頁・発行日

pp.109, 2017 (Released:2017-06-19)

著者

中原 健志 藤本 孝

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.862, pp.18-00017, 2018 (Released:2018-06-25)

参考文献数

15

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A semi-active vibration control technique using piezoelectric actuators with switched inductance shunts has been studied. This technique can be used for not only vibration suppression but also energy harvesting. In order to design semi-active vibration control systems and energy harvesters using this technique efficiently, it is necessary to analyze and understand the effects of design parameters on the performance of these systems. Responses of these systems to harmonic disturbance forces can be used for performance evaluation and previous studies analyze periodic responses of semi-active vibration control systems by assuming sinusoidal displacement responses and using method of harmonic balance. However, this control technique induces rectangular control forces and the displacement responses are distorted. Enhancing the control forces leads to stronger distortion of the responses and the validity of the assumption of the previous studies becomes lost. In order to overcome this problem, the authors have proposed to use shooting method which is a numerical method to calculate periodic solutions of non-linear systems without assuming certain forms of responses. This paper presents periodic responses obtained by shooting method with an improved non-dimensional model and the periodic responses are compared with ones obtained by method of harmonic balance. Furthermore, this paper considers not only the periodic responses but also non-periodic chaotic responses obtained by long term simulations with the non-dimensional model.

著者

稲垣 耕 盆子原 康博 近藤 孝広 池 美慧 濵畑 貴之

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.862, pp.18-00004, 2018 (Released:2018-06-25)

参考文献数

4

被引用文献数

1

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In household refrigerators, the rotational speed of a reciprocating compressor can be appropriately adjusted according to the temperature inside of the refrigerator. The lower rotational speed reduces the power consumption of the compressor. However, several natural frequencies of the compressor exist in the low rotation region, and besides, the unbalance force arising from the piston motion acts on the internal drive unit. Thereby the vibrations of the compressor are likely to be larger due to the resonance in the low rotation region. In this study, a method for supporting the drive unit inside the shell, which is called “the self-standing support” is newly proposed in order to reduce the vibration of the compressor drastically. In the proposed method, a spherical support element is utilized instead of coil springs to support the drive unit. And the drive unit can maintain a stable self-standing state by acting restoring moment due to the gravity while it is directly placed on the shell. The natural frequencies of the compressor can be greatly reduced by decreasing the support stiffness for the drive unit in comparison with the support method using coil springs. Furthermore, in designing the drive unit, the application point of the exciting force is matched with the center of percussion to the contact point on the spherical support. As a consequence, the periodic restraining force acting on the contact point can be minimized. By these two features, it is possible to considerably reduce the vibration transmission from the drive unit to the shell. In the present study, a simplified model for a reciprocating compressor is treated, and the effectiveness of the self-standing support is investigated analytically and experimentally.

著者

木村 秀行 土田 崇弘 木村 康治

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.862, pp.17-00586, 2018 (Released:2018-06-25)

参考文献数

14

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In this study, vibration characteristics of a single-degree-of-freedom linear oscillator with the fractional order derivative are examined in terms of the critical damping over a wide range of the order of the fractional derivative by using numerical analysis. Two types of the definitions of the critical damping used in the previous studies are considered. It is shown that (i) the critical viscoelastic damping ratio changes according to the order of the fractional derivative and its minimum value for both types of the critical damping is less than 1; (ii) no critical viscoelastic damping ratio is observed in a certain range of the order; (iii) the difference in the existence of the critical damping between the oscillators with the derivative of order 1/3 and 2/3 is caused by the change of the behavior of a component of the response corresponding to one of the roots of the characteristic polynomial for the oscillator. Finally, the impulse response characteristics are classified into three classes depending on the order of the fractional derivative and viscoelastic damping ratio of the oscillator.

著者

山崎 徹 曽根 崇正 橋本 崇史 黒田 勝彦

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 B編

巻号頁・発行日

vol.78, no.789, pp.988-992, 2012

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Experimental Statistical Energy Analysis (ESEA) is applied to analyze the vibration energy flow on violin body. The violin body is subdivided into six SEA subsystems. The analysis can identify the power flow through the subsystems and the power input into each subsystem under the impact excitation at the bridge which connects the strings and the body. The analysis results for two kinds of violin are compared. It is shown that three pieces of knowledge regarding better violin are obtained as the followings, 1) damping of the body structure is small, 2) the frequency distribution of power input into the body is in inverse proportion to square root of frequency and 3) the vibration energy on the back plate is propagating only from the top plate through the sound post. The fundamental discussions on the knowledge 2) and 3) are also carried out.

著者

真鍋 敦行

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.120, no.1189, 2017

著者

大塚 章正 永田 寅臣 中村 航輔

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.2014, pp._3P1-L01_1-_3P1-L01_3, 2014

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In full mold casting, polystyrene is used as a master mold that is usually machined by a CNC machine tool. The CNC machine tool costs higher and does not move more flexibly than an articulated industrial robot. We have proposed a trajectory following controller system for a machining robot based on CL (cutter location) data. In this system, the discrete trajectories at each sampling time are generated from position and orientation information in CL data that are made by post processor in CAM system. We applied the controller system to foamed polystyrene machining while changing conditions, such as foaming rate of polystyrene, feed rate of end mill and processing number of times. In this paper, machining results of a simple model are shown and discussed. Finally, we consider the method to reduce the machining time while keeping machining accuracy and products quality.