著者

佐藤 勇気 山田 崇恭 泉井 一浩 西脇 眞二

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.83, no.851, pp.17-00081-17-00081, 2017 (Released:2017-07-25)

参考文献数

29

被引用文献数

2

---

This paper proposes a scheme for imposing geometrical constraints in topology optimization for molding and milling so that optimal configurations that guarantee manufacturability can be obtained, based on the fictitious physical model. First, a level set-based topology optimization method is briefly described, and geometrical requirements for molding and milling are clarified. In molding, molded products must embody certain geometrical features so that mold parts can be separated, and milling cannot proceed unless the desired shape allows tool cutting faces to reach the workpiece. A fictitious physical model described by a steady-state advection-diffusion equation is then constructed based on the requirements. In the fictitious physical model, material domains are represented as virtual heat sources and an advection direction is aligned with a prescribed direction, along which mold parts are moved, or attitude in the case of a milling tool. Void regions, where the value of the fictitious physical field is high, represent either undercut geometries which would prevent the mold from being parted, interior voids that cannot be manufactured, or regions that a milling tool cannot reach. Next, a geometrical constraint is formulated based on the fictitious physical model. An optimization algorithm is then constructed. Finally, in the numerical examples, the proposed method yields manufacturable optimal configurations, confirming the validity and the utility of the proposed method.

著者

仙波 卓弥 天本 祥文 角谷 均

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.83, no.851, pp.16-00573-16-00573, 2017 (Released:2017-07-25)

参考文献数

9

被引用文献数

2

---

A linear machining technique using a nanosecond pulsed laser, adaptable for forming a single-point cutting tool made of nano-polycrystalline diamond, was developed. A basic study to find the principal rules of linear machining was conducted by forming an inclined face against the beam axis that is coincided with the Z axis. The face was formed by conducting repeatedly a set of machining processes, comprising linear machining to remove chips and zero-cut machining to remove the residual stock. It was verified through a machining test that the removal depth in the Z direction was independent of the inclined angle of the face. In addition, the stock removal in the Z direction coincided with the sum of the applied depths of cut in the Z direction when the residual stock removal in each machining step was eliminated by the zero-cut machining. These basic rules made it possible to accurately fabricate a convex dimple with a diameter of 0.2 mm, during which the inclined angle of the machined face against the beam axis varied at every position, by repeatedly conducting the set of machining processes. Also, it was verified through the forming test of a single-point cutting tool with a nose radius of 0.4 mm that the linear machining technique enabled the fabrication of the tool with a shape accuracy better than 1 μm and a cutting edge radius of less than 250 nm.

著者

田辺 郁男 西山 晃 五宝 純一 高橋 智

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.83, no.851, pp.16-00449-16-00449, 2017 (Released:2017-07-25)

参考文献数

15

---

As accuracy of industrial product was reduced by thermal deformation of a machine tool, a tool and a workpiece during cutting, there are several countermeasures for machining field. In the old days, we had developed and evaluated for a lathe with insensibility function for thermal and temperature change. The lathe has the structure of zero-center on three directions, the structure of self-compulsory cooling and the structure of thermal synchronism. Particularly the structure of thermal synchronism was developed for wet cutting. However the control method for the structure of thermal synchronism was yet to establish. Therefore the control using thermal synchronism at wet cutting in machine tool was developed and evaluated. The control system of fluid quantity on the structure of thermal synchronism using inverse analysis of neural network was developed for insensibility function of thermal and temperature change. Then thermal deformations of the developed lathe were measured and evaluated in the several experiments. It is concluded from the results that; (1) Thermal deformation of the bench lathe was very small in spite of no-forced cooling, (2) The control system of fluid quantity on the thermal synchronism using inverse analysis of neural network was effective for its working stability during wet cutting.

著者

高野 直樹 石島 慎太郎

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.83, no.851, pp.17-00216-17-00216, 2017 (Released:2017-07-25)

参考文献数

30

被引用文献数

1

---

There is a growing need for molding process simulation of fiber reinforced plastics (FRP) in determining an appropriate set of process parameters, because a large number of process parameters exist and moreover those parameters have uncertainty or variability. Stochastic process simulations have been studied so far such as the Monte Carlo simulation (MCS), which provides us the expected value and standard deviation of the quantity of interest (QoI), considering the variability of input parameters. However, the results in the tail distribution were not highlighted except the authors' previous reports. This paper proposes a modified sampling scheme named stepwise limited sampling (SLS) to generate sampling points more efficiently and accurately in the multi-dimensional input parameter space, which lead to the tail distribution of QoI. The proposed method was applied to a resin transfer molding (RTM) process simulation considering 31 random parameters. Compared to the conventional MCS using 10,000 sampling points, it was demonstrated that enough number of cases in the tail distribution was analyzed by the modified method using only 1,700 sampling points.

著者

上杉 謙介 橋本 雅文 高橋 和彦

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.83, no.851, pp.17-00129-17-00129, 2017 (Released:2017-07-25)

参考文献数

13

---

This paper presents a method for detecting and cancelling motion artifact related to standing and walking in a functional near-infrared spectroscopy (fNIRS) signal. Our fNIRS device has 22 channels. The motionless fNIRS signal from each channel is represented by a fourth-order autoregressive model (AR model), and the related parameters are estimated based on the motionless fNIRS signal using Yule Walker equation. The motion artifacts included in the fNIRS signal are cancelled using the Kalman filter constructed from the AR model. However, the cancellation may be insufficient when the motion artifacts are strong. To determine in which fNIRS channels the motion artifacts are cancelled insufficiently, we apply an observation prediction error related to the Kalman filter and a discrete Fourier transform. The brain activity of the user is then recognized from those fNIRS channels in which the motion artifacts are cancelled sufficiently. To evaluate the proposed method, a mobile robot is controlled using an fNIRS devise as worn by 10 subjects while standing, walking, or sitting. The success rate of brain-activity recognition by the proposed method was 64.2%, whereas that without the proposed method was 54.0%.

著者

大野 昌嗣 中妻 啓 大嶋 康敬 鳥越 一平

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.83, no.851, pp.17-00112-17-00112, 2017 (Released:2017-07-25)

参考文献数

16

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The pressure change leak test detects a leak from the pressure drop observed after the container under test is filled with compressed gas and then closed. This method has the serious disadvantage of being sensitive to the temperature variation in the target container. We propose a new method using exponential analysis to compensate for exponential temperature variation in pressure change leak detection. In the proposed method, two successive leak tests are performed at different initial compression pressure. Exponential parameters of the temperature variation in the gas within the container are determined from the pressure signal in the first test, and the pressure in the second test is predicted using these parameters. The leak in the container is estimated from the difference between the predicted pressure and the measured one. Experimental results using a prototype leak detector and model piping showed that leak can be successfully detected without being affected by the given exponential temperature variation. With the proposed method, it was able to shorten the total test time by as much as 65% in comparison with the case in which a conventional leak test is performed after waiting until the exponential temperature variation settles. An algorithm using Discrete Fourier Transform for estimating exponential parameters from finite length data of pressure signal is also presented.

著者

北川 湧麻 満田 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 (ISSN:21879761)

巻号頁・発行日

vol.83, no.851, pp.17-00107-17-00107, 2017 (Released:2017-07-25)

参考文献数

23

---

A flexible bag containing particles becomes rigid when the air inside the element is evacuated. Variable stiffness elements using granular jamming have been used for haptic displays and robotic orthoses helped by the soft and lightweight body. However, deforming variable stiffness elements causes wrinkles on the membrane, which decrease and destabilize the stiffness of the element. The wrinkles on variable stiffness elements are due to the non-stretchability of the outer membrane. A stretched membrane reduces wrinkles but decreases the stiffness of the element dramatically. This study suggests a wrinkle-free variable stiffness element with an outer membrane that is stretchable but rigid only when the air inside the element is evacuated. The amount of particles inside conventional elements limits the deformable range of the elements. On the other hand, the novel stiffness element can hold more particles without any loss of the deformable range, which increases the stiffness of the element. The stretchable outer membrane also reduces undesirable deformations of the element caused by wrinkles when the air inside the element is evacuated. The experimental results of this study confirm that the stiffness of the wrinkle-free variable stiffness element is greater and more stable than a conventional stiffness element.

著者

神谷 恵輔

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.83, no.851, pp.17-00101-17-00101, 2017 (Released:2017-07-25)

参考文献数

11

被引用文献数

4

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This paper presents a method for analysis of motion of multibody systems. In the presented method, the null space matrix for the constraint Jacobian is determined by solving differential equations, not by solving algebraic equations which is common in other methods such as the coordinate partitioning method and the null space method. In the algorithm, the QR decomposition for the constraint Jacobian is utilized. Use of the differential equations for the null space matrix and the QR decomposition as well as the introduction of stabilization terms allow us to analyze without any problems motion of multibody systems which have redundant constraint and/or singular configuration. In addition, the presented method solves the Maggi's equation which is the equation obtained by eliminating the Lagrange multipliers from the equation of motion and by expressing the unknown variables only with the independent components. Thus the computational cost is not so high. The validity of the presented method is verified by numerical examples.

著者

安田 正志 佐藤 栄児 山田 学 梶原 浩一 早津 昌樹

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.83, no.851, pp.17-00057-17-00057, 2017 (Released:2017-07-25)

参考文献数

10

被引用文献数

5

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Vibration tests of the prototype of the newly developed three-dimensional seismic isolation mechanism were carried out using several real-scale three-dimensional seismic waves with the world's largest E-defense shaking table. The developed 3-D seismic isolation mechanism has an air levitation mechanism that isolates horizontal vibration and a spring link mechanism that isolates vertical vibration, in series. The air levitation mechanism floats only 50 μm from the floor and is in contact with the floor with a slight air viscous force of a friction coefficient of 1/1000. Since there is no spring force in the horizontal direction in this mechanism, there is no periodic motion and there is no amplification of vibration. Also, since the floating height is very small, the vertical rigidity is very high even in the air, and the rocking motion is not performed. The spring link mechanism combines a negative stiffness link and a positive stiffness link to minimize the spring stiffness. While maintaining the horizontal attitude by the link, a vertical natural frequency of 0.25 Hz was realized. The prototype showed unprecedented high performance of about 20 dB of anti-vibration capability at 1 Hz both in the horizontal and vertical directions, and the effectiveness was verified in this experiment. The seismic waves used for the experiment are the Takatori seismic wave of the Great Hanshin-Awaji Earthquake of 1995 and the Sendai seismic wave of the Great East Japan Earthquake of 2011.

著者

望月 典樹 中村 壮亮 橋本 秀紀

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.83, no.851, pp.17-00022-17-00022, 2017 (Released:2017-07-25)

参考文献数

32

被引用文献数

1

---

Immersive virtual reality system has a problem that the operability deteriorates if the shape of the virtual body is parted from the real body. The authors are assuming that this is caused by misfit of the body scheme, an internal model in the brain used to recall the body position, because it is initially tuned up to the real body instead of virtual body. Thus, the authors have proposed a method using VR technology called“ Body Scheme Calibration ”to change the body scheme adapting to the real body so as to fit the virtual body. However, in the previous approach, presented VR information was limited to visual information, and haptic information normally occurring from interaction with surrounding object was neglected. Therefore, this paper investigated the effect of haptic information on Body Scheme Calibration. As an experimental result, it was verified that the effect of additional haptic information is trivial, and the complex haptic interface for this calibration might be omissible.

著者

中本 秀一 松日楽 信人 桑原 裕之 廣瀬 茂男

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.83, no.851, pp.16-00556-16-00556, 2017 (Released:2017-07-25)

参考文献数

9

被引用文献数

1

---

In this paper, we described the principle, design prototype and evaluation of of 3-dimensional gravity compensation mechanism for human coexistence robot. In this mechanism, it is possible to realize 3-dimensional gravity compensation by rotating the entire pantograph mechanism at the root and arranging actuators as counterweights so as to balance moments of all joints. We derive the relationship such as the link length and the center of gravity position to realize this. In addition, by constructing a mechanism that adds compensation force using wires, the entire arm is made as compact as possible. From the joint torque simulation and experiment of the prototype arm, it was confirmed that the arm can be driven with joint torque of 15% to 25% with respect to the arm without compensation meshanism. In addition, it was found that the effect of reducing the torque supporting the arm's own weight was larger than the influence of the increase of the moment of inertia by counterweight.

著者

田中 嘉津彦 藤田 祐介

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.83, no.850, pp.16-00540-16-00540, 2017 (Released:2017-06-25)

参考文献数

16

被引用文献数

2

---

The friction characteristics on sliding part between piston and cylinder in a swash plate type piston pump in which improvement of the power density is demanded affect the equipment performance and the efficiency. In this paper, targeting a straightly cylindrical piston and tapered pistons, the effects of geometric shape of the piston on the friction characteristics have been investigated based on both the results of friction force measurement using a model machine and the numerical calculation considering mixed lubrication. Moreover, the effectiveness of adopting each of the pistons to the swash plate type piston pump has been examined from view point of friction characteristics. The results are summarized as follows: (1) Optimum taper angle of the piston which can improve the friction characteristics will exist under severe lubrication conditions. (2) The degree of friction characteristics improvement can be formulated as a function of the Sommerfeld number which is one of important parameters to determine the bearing performance. (3) Adoption of tapered pistons may improve the friction characteristics under mild lubrication conditions. (4) The tapered piston will whirl widely in the cylinder than in the case of the straightly cylindrical piston, load carrying capacity due to squeeze effect of the fluid can be expected to increase.

著者

小野 京右

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.83, no.850, pp.17-00091-17-00091, 2017 (Released:2017-06-25)

参考文献数

26

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Vibration characteristics of a flying head slider in hard disk drives at touchdown attract strong interest because head‒disk spacing must be decreased to less than 1 nm in order to increase recording density. This study first evaluates head‒disk interfacial force based on rough surface adhesion contact models and a simple air-bearing force model. Then, microwavinessexcited vibration of single-degree-of-freedom slider model at touchdown was numerically simulated in more detail than the previous study. It was found that the slider exhibits a MW-excited vibration having low frequency components of less than 100 kHz at touchdown and shifts to severe contact state near the boundary of static instability onset. When a small static unstable region is generated by decreasing air-bearing stiffness ratio, the occurrence of the low frequency spacing variation is interrupted by temporal flying state (loss of contact). When the static unstable region further increases by decreasing air-bearing stiffness ratio, the spacing variation with low frequencies can appear only at the beginning of contact and immediately jumps to a light contact state and then shifts to a perfect flying state during a long input power range and eventually jumps to a heavy contact state. These calculated results seem to correspond to the actual slider dynamic behaviors at touchdown in the inner, outer and middle diameter regions. The possibility of surfing recording is discussed from the analytical and experimental evidences.

著者

吉田 秀久 小嶺 長芳 山口 秀谷

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

pp.15-00116, (Released:2015-05-22)

参考文献数

19

---

For the design of steering assistance system when running at high speed and modeling of a driver model necessary to effect evaluation and inspection, goal of this research is to make the driver model which models the driver's steering torque over a series of steering behavior. First step of this research, modeling of a driver steering in high-speed running is targeted for the steering torque behavior during the lane change that a driver steers actively and lane keeping that a driver keeps the lane under the crosswind disturbance passively. So the modeling for the steering torque behavior is proposed considering the lateral deviation in the front view point and the reaction torque from the steering wheel. It is proposed that the steering torque state transition changes from a course change action to a lane keeping action. It is confirmed that reproducibility of lane keeping action to an experimental result improves. Significant test did the driver parameter and its feature is made clear.

著者

高橋 翼 中村 寛子 木村 啓志

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.83, no.850, pp.16-00560-16-00560, 2017 (Released:2017-06-25)

参考文献数

16

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Nowadays, in vitro fertilization (IVF) of mammalian embryos is an essential technique in the reproductive technology and other related life science fields. However, the fertility rate by this technique is still less than 25%. Therefore, a novel in vitro fertilization method which obtains high fertility rate has been highly desired to the reproductive technology. In this study, we proposed and developed an in vitro embryo production device which allows three steps of sperm selection, fertilization and culture on a microdevice. To realize this concept, we integrated the sperm sorting function combining with swim-up and swim-down methods onto the device. To evaluate the device functions, sperm sorting experiment, in vitro fertilization experiment, and embryo culture experiment have been carried out. As results, we concluded that the device has ability to produce high quality embryos by integrating the sperm sorting function. This concept will open and enhance the management of in vitro fertilized embryos for assisted reproductive technology, livestock breeding, and fundamental stage research by further development.

著者

重松 康祐 坪内 孝司 皿田 滋

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.83, no.850, pp.17-00040-17-00040, 2017 (Released:2017-06-25)

参考文献数

14

被引用文献数

1

---

This paper describes tip-over prevention control of a teleoperated excavator based on center of gravity (CoG) and zero moment point (ZMP) prediction. This method predicts a future CoG and ZMP when an operation input is given. This allows the determination of the risk of tip-over by the operation input before an excavator moves. When the risk is detected, the operation input to the actuator is modified or stopped automatically to prevent from tip-over. Future CoG and ZMP is predicted by computing the movement of a teleoperated excavator based on an approximate excavator movement model. The proposed method successfully demonstrates tip-over prevention via scaled model experiments of the hydraulic drive.

著者

山田 泰之 吉浜 舜 岩崎 祥大 芦垣 恭太 松本 幸太郎 羽生 宏人 中村 太郎

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.83, no.850, pp.16-00576-16-00576, 2017 (Released:2017-06-25)

参考文献数

13

被引用文献数

1

---

In recent years, the demand for rocket launching has increased due to the development of space technology. However, using inexpensive rockets is not always possible. Although the cost of solid-propellant rockets is relatively reasonable, safely manufacturing a large amount of solid propellant is difficult, and the manufacturing process is disjointed. Therefore, safe and continues manufacturing of solid propellant is necessary. On the basis of the movements of the intestinal tract, we proposed that the movements required for transport and mixing of solid propellants are possible to achieve without the application of a large shear force. The peristaltic motion enables not only the mixing but also conveying even high viscosity slurry. By mimicking these intestinal movements, we have considered and developed the peristaltic pumping by driven artificial muscle as one of the candidates for the continuous and safety mixer. In this research, the mixing completeness of the composite solid propellant slurry by the peristaltic pumping mixer was estimated. The result showed that the mixer we proposed could mix the propellant slurry. In the propellant samples, these variances were sufficiently small. An appropriate combustion state as a solid propellant was confirmed.

著者

坂本 秀一 石田 宗弘 珍田 美月

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.83, no.850, pp.16-00575-16-00575, 2017 (Released:2017-06-25)

参考文献数

14

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In this article, we examined several longitudinal-sectional sizes of a silencer whose volume was limited by the thickness and aperture ratio of the ventilation door. We report the results of improvement in the sound attenuation properties of these shapes. As an evaluation method for the silencer, we measured transmission losses using an impedance measurement tube and calculated them on the basis of a theoretical analysis. The following results were obtained from the evaluation of the silencer using the measurement and calculation results and from the verification of the improved shape of a silencer and silencer array. For a side branch tube silencer with a 1/3 aperture ratio, assuming that it is installed into the ventilation door, we observed a side branch tube with an linear expanded longitudinal-sectional shape by improving the shape using the theoretical analysis of transmission losses. In addition, as a result of the experiment with a sample on the basis of the theoretical analysis, both the experimental and the theoretical analysis were in good agreement. Furthermore, the expanded shape of the longitudinal-section of the side branch tube decreased the frequency of the sound attenuation peak. It was found that a silencer with a combination of four of these silencers can be arrayed side-by-side in a ventilation door; this results in a flat transmission loss of more than 5 dB over a broad band.

著者

大久保 光 福田 宙央 坪井 涼 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

pp.15-00679, (Released:2016-06-10)

参考文献数

13

被引用文献数

1

---

Tribological properties of a diamond-like carbon film were investigated under lubrication with commercial fully formulated oils. Friction tests were carried out for a hydrogenated amorphous carbon (a-C:H)/steel tribopair under lubrication with the four types of fully formulated oil using a reciprocating type ball-on-disk tribo-tester. To clarify the friction and wear mechanisms, surface analysis, such as Raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS) and atomic force microscopy (AFM), were conducted on the wear tracks of a-C:H disks. The results of friction tests and surface analysis show that the properties of tribofilms on DLC films play important roles in determining the tribological properties of DLC films under lubrication with fully formulated oils.

著者

今西 大輔 西名 慶晃 栗原 康行

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.83, no.850, pp.16-00554-16-00554, 2017 (Released:2017-06-25)

参考文献数

8

被引用文献数

1

---

In recent study, active thermography has reached a high status as an easy and speedy defects inspection method in a NDT field. This paper newly proposes a remote and non-contact NDT method using a sonic-IR for detecting and evaluating of fatigue cracks at runway girder of the overhead crane in the steel making plant. In this method, fatigue cracks are detected as localized high temperature areas caused by friction and collision at crack surfaces with an infrared camera, applying a high-amplitude ultrasonic vibration. In this paper, sonic-IR method is applied to remote and high-efficient crack inspection of the runway girder in the overhead traveling crane. Target crack located in high place can be detected using this method without setting up scaffolding for inspection. And the threshold of vibration amplitude to generate the sufficient heat for crack detection is clarified. Therefore the system to prevent missing the crack by unsuccessful vibration transmission from vibrator is developed applying monitoring the vibration.Time and cost saving inspection method in runway girder of the overhead traveling crane is carried out using this NDT technique.