著者

伊丹 琢 藪名香 俊人 家喜 湧大 矢野 賢一 山本 亮 小林 安之 篠田 信之 青木 隆明 西本 裕

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.856, pp.17-00291-17-00291, 2017 (Released:2017-12-25)

参考文献数

15

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We previously proposeda power assist robot and conductedexperiments for cervical cord injury(CCI) patients. This paper proposed a new type of robot orthosis by making of their residual function around their shoulder in order to operate the wheelchair. A lock/unlock mechanism on the elbow joint is effectively used to transmit the residual function around the shoulder to the hand. We confirmedthat three patients with CCI could use their residual functionaround their shoulderand operate a wheelchair effectively in outdoor environment like high resistance roads and roads with a slope by measuring velocity of the wheelchair and electromyography of his shoulder muscle.

著者

吉竹 直樹 張 慧 萩原 良道

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 2007 (ISSN:24242896)

巻号頁・発行日

pp._114-a_, 2007-11-17 (Released:2017-06-19)

著者

湯淺 朋久 阿部 豊 平野 覚

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.856, pp.17-00309-17-00309, 2017 (Released:2017-12-25)

参考文献数

17

被引用文献数

2

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Toward the improvement of performance of the electric vehicle (EV), the design of the motor shape appropriate to heat removal is important. A typical EV motor is composed of a pair of coaxial cylinders with a fixed outer cylinder (stator) and a rotating inner cylinder (rotor). Some EV motors have axial slits on the stator wall. The present study numerically clarifies the physical mechanism of difference of Nusselt number between the case with slit and without slit. The heat transfer of the gap between the rotor and stator was obtained by the numerical calculation. A vortex structure observed by flow visualization experiment was reproduced in the numerical simulation, and velocity profiles showed good agreement with experimental data. The heat transfer rate for the case with slit in the high rotational speed was increased compared with that for the case without slit. Nusselt number was decomposed into the three terms which were the advection, turbulent transport and diffusion terms; the advection term of heat flux for the case with slit was increased compared with that for the case without slit because of the vortex structure. The Nusselt number on the slit surface was increased compared with that on the gap surface for the case with slit. It was implied that the difference of Nusselt number between the case with slit and without slit was caused by the presence of the vortex structure in the slit and the increase of heat flux for the case with slit.

著者

青木 祐 池田 憲亮 伊藤 友孝

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 2016 (ISSN:24243124)

巻号頁・発行日

pp.1A1-08a4, 2016 (Released:2017-06-19)

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The maintenance and management of mountain forest needs special knowledge and skill, and contains various dangerous tasks. Thus, the shortage of workers causes the problem of increasing unmanaged forests. In this research, we are developing “Teleoperated mountain forest maintenance robot system”, which assist human work semiautonomously. In this paper, we will discuss and propose a performance improvement method in recognizing process of the surrounding objects in the mountain forest environment. The experimental results illustrate the validity of the proposed method.

著者

小田 尚輝 日下部 正美

出版者

一般社団法人 日本機械学会

雑誌

日本機械学會論文集 (ISSN:00290270)

巻号頁・発行日

vol.18, no.74, pp.72-75, 1952 (Released:2008-03-28)

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In this study, we compared two vibration characteristics of a car below the resonant speed, in a case, used as a motor car, and in the other case, used as a trailer. In the case of a motor car, about a half of motor weight is assumed to be unsprung weight over the trailer one. Results of the studies are as follows : -1°The natural periods of the car are not significantly different in the two cases, in both the vertical and transversal vibrations. 2°As to the vertical vibration. (1) Under 70 km/h, the heavier the unsprung weight becomes, the larger the vibration increases. (2) From 70 to 82 km/h, there are no difference. As to the transversal vibration. (3) Under 65 km/h, the vibration is larger in the heavier unsprung weight. (4) From 65 to 75 km/h, there are no difference. (5) Over 75 km/h, the vibration is rather small in the heavier unsprung weight.

著者

吉川 穣 西尾 悠 伊澤 精一郎 福西 祐

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.17-00478, (Released:2017-12-20)

参考文献数

15

被引用文献数

2

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Numerical simulations are carried out aimed at finding a key flow structure which leads to a laminar-turbulent transition of a boundary layer with streaky structures. In the preliminary computation, an array of cuboids is used to form streaky structures inside a boundary layer. Then, a disturbance is introduced into the boundary layer by ejecting a short-duration jet from a hole in the wall into a low-speed region in the streaky structures. Although the boundary layer returns to a laminar state when the jet velocity is set to 18% of the uniform flow velocity, it eventually turns into a turbulent state downstream in the 20% case. The differences are investigated in detail in terms of the vortical structures. As a result, only in the stronger jet case, a flat spanwise vortex is generated beside one leg of a hairpin vortex and it merges with the streamwise vortex nearby forming an inclined streamwise vortex. On the other hand, the flat spanwise vortex disappears without being connected to the streamwise vortex in the weaker jet case. The inclined streamwise vortex is stretched by the mean velocity gradient of the boundary layer growing into a strong vortex, and new vortex structures are generated around the inclined one, which leads to turbulence. Therefore, the results suggest that formation of the inclined vortex is the key to transition of the boundary layer.

著者

山内 仁史 山﨑 慎太郎 矢地 謙太郎 藤田 喜久雄

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.855, pp.17-00320-17-00320, 2017 (Released:2017-11-25)

参考文献数

23

被引用文献数

1

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Multi-fidelity analysis has been used for reducing the calculation cost of evaluating the design solution, which is the most costly process in design optimization. In general, multi-fidelity analysis is applied to problems with continuous design variables, which are suitable to construct an approximate model of design space such as the response surface. On the other hand, combinatorial optimization problems, e.g., layout design, are difficult to apply the conventional multi-fidelity analysis, since the response surface cannot be constructed due to the property of the design variables. In this paper, we propose a multi-fidelity optimization method independent of the response surface and a simple analysis model for the method, and apply them to multi-disciplinary optimal layout design problem which is a complicated combinatorial optimization problem. The proposed analytical model, which adopts the concept of the explicit method, realizes for reducing the calculation time by simplifying the physical phenomenon. Then, the multi-fidelity optimization method is constructed by combining the proposed analysis model with the thermal network method which is a well-known thermal analysis method. We confirm that there is a strong correlation between the calculation result of the proposed analysis model and of a CAE software, and show that the proposed analysis model is suitable as a low fidelity model. The effectiveness of the proposed optimization method is demonstrated through numerical experiments.

著者

片峯 英次 岡田 直也

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.83, no.855, pp.17-00407-17-00407, 2017 (Released:2017-11-25)

参考文献数

19

被引用文献数

2

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This paper presents numerical solution to two shape design problems of unsteady forced heat-convection fields to control temperature to a prescribed distribution. In the first problem, the square error integral between the actual temperature distributions and the prescribed temperature distributions on the prescribed sub-domains during the specified period of time is used as the objective functional. In the second problem, a multi-objective shape optimization problem using normalized objective functional is formulated for the temperature distribution prescribed problem and the total dissipated energy minimization problem in the unsteady forced heat-convection fields. Shape gradient of these shape design problems is derived theoretically using the Lagrange multiplier method, adjoint variable method, and the formulae of the material derivative. Reshaping is carried out by the traction method proposed as an approach to solving shape optimization problems. Numerical analyses program for the shape design is developed based on FreeFem++, and the validity of proposed method is confirmed by results of 2D numerical analyses.

著者

野間口 大 董 春祉 堀之内 貴大 藤田 喜久雄

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.854, pp.17-00167-17-00167, 2017 (Released:2017-10-25)

参考文献数

18

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The product design project includes many uncertainties. It causes risk that a project target cannot be accompolished within lead time. In order to flexibly handle the uncertainty and avoid the risk, adaptive planning that can switch easily to another plan by preparing options for a task is needed. When a challenging design alternative is difficult to be accompolished, a project manager should decide either to continue the design taking a risk or to switch to a conservative alternative disliking a risk. This paper proposes a new optimization-based project planning method that aims at a Pareto-optimal of the potential technical performane of designed product and a project failure risk. A task option model is employed for risk assesment of option-based project management. As its planning includes a number of various design variables and various evaluation indices, in order to solve such a complicated problem with a reasonable computation cost, this research separates the optimization problem into two phases, i.e., (i) defining of process architecture and organization structure and (ii) scheduling of resource allocation into activities. This paper demonstrates its application to a student formula design project. A proposed optimization method facilitates a project manager to explore various process plans with assessing their risks.

著者

遠藤 広晴 菊地 史倫 斎藤 綾乃 辻村 壮平 林 伸明

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.83, no.854, pp.17-00089-17-00089, 2017 (Released:2017-10-25)

参考文献数

21

被引用文献数

2

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In this study, the relation between the thermal environment and the thermal comfort of occupants in a main line vehicle in the summer was investigated. At first, to understand the characteristics of the thermal environment in a main line vehicle, a field survey was conducted by measuring the temperature and humidity in regular passenger services from the morning to the night. The observation range of the temperature was from 23°C to 28°C, and that of the humidity was from 38%rh to 68%rh. Then, to obtain the fundamental data about the occupants’ thermal comfort, a subjective experiment in which 44 subjects in total participated was carried out. The subjects rode a main line vehicle stationed at a rolling stock center, and they experienced the temperature changing approximately in the range observed in the field survey and answered the questionnaires about their thermal comfort. Furthermore, the relationships between the thermal indices called PMV/PPD and the subjective evaluation values were analyzed. As a result, it was indicated that the error of the PPD in predicting the percentage of dissatisfied subjects became large in the range PMV>0, where the effect of the sweat sensation became significant. However, the PPD agreed well with the actual percentage of people who reported to have the feeling of ‘slightly cold’, ‘cold’ or ‘slightly hot’, ‘hot’. Our results suggest that the PPD can be used as an index of the variability of thermal sensation, but not as an index of thermal comfort in a main line vehicle in the summer; in order to use the PPD as an index of thermal comfort all the year around, it should be corrected taking into account the seasonal characteristics of the relation between the PMV and the actual percentage of dissatisfied occupants.

著者

大北 由紀子 菅沢 深 毛利 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.83, no.854, pp.17-00085-17-00085, 2017 (Released:2017-10-25)

参考文献数

9

被引用文献数

2

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It has been well known that the drivers' looking aside behavior is one of the cause of traffic accidents. However, it is difficult to investigate the causal relationship between the looking aside and accident. The authors analyzed the features of drivers' looking aside behavior by using the drive recorder data. It is found that this behavior occurs when three conditions stated below are satisfied. The first one is that the time headway is long enough. The second one is that the required deceleration for collision avoidance is supposed to be small. The third is that there is enough time for the drivers to push brake pedal and stop the car safely. Drivers' looking aside behavior under dangerous situation doesn't always lead to an accident, but when the looking aside period is too long, this behavior tends to cause an accident. In addition to the above, it is found that in the low speed range, drivers try to keep a constant headway distance. The mechanism of this trend is clarified.

著者

辻江 正裕 吉岡 亜陸 水谷 祐貴 曄道 佳明

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.83, no.854, pp.17-00074-17-00074, 2017 (Released:2017-10-25)

参考文献数

25

被引用文献数

6

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In recent years, railway system is attracting attention in terms of energy efficiency and environment friendliness. Rail of railway is one of the most important elements in constructing railway system. Railheads are subjected to severe contact with wheels during repeated passage of vehicles. As a results of severe contact with wheels, wear of rail or rail defect have been occurred on railheads. Rail profile will be changed due to wear development. Worn profiles of rail have changed complexity in each section because the condition of wheel/rail contact has changed gradually, according to the running condition of vehicle and track geometry condition. Therefore, it is very important to predict the worn profiles of rail based on the analysis of vehicle dynamics. Previously, we constructed the prototyped model for predicting worn profiles of rail with Simpack. However, the validation of this model has not been verified. In this study, we conducted the wear experiments by use of full-scaled wheel/rail rolling contact equipment to distinct the coefficient of wear and to measure the worn profiles for validating the prediction model. Moreover, we analyzed the worn profile of rail in the same contact condition with the wear experiments. Finally, we considered the results of wear depth and the contact patch of wheel/rail discs of this equipment in analysis and experiments. As a result of the analyses and experiment, the analytical model was confirmed being valid to predict worn profile of rail.

著者

山下 ノボル

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:00214728)

巻号頁・発行日

vol.109, no.1054, pp.748-749, 2006

著者

山田 健介 宮本 共生 臼井 清一

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.71, no.708, pp.2557-2562, 2005-08-25 (Released:2011-03-04)

参考文献数

8

被引用文献数

4 4

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The paper presents a design and characteristics of a new holonomic omnidirectional moving vehicle, which simultaneous and independently controlled translational and rotational motions. The moving vehicle has four rubber balls instead of wheels. Each ball is driven by two rotating rollers. But the system has only four actuators. The kinematics of the moving vehicle is analyzed and the control algorithms are derived for the holonomic and omnidirectional moving vehicle. The experimental results show that the proposed new type of moving mechanism has good characteristics and the sensor on board is useful for autonomous moving under relatively large disturbance.

著者

水谷 昌平 山﨑 楠人 林 隆三 宮澤 邦幸 三浦 義章

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.83, no.853, pp.17-00026-17-00026, 2017 (Released:2017-09-25)

参考文献数

10

被引用文献数

1

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Elderly caregivers are increasing by aging of society in Japan. One of the hardest action for them is to make a wheelchair with a person on climb a step. In order to reduce burdens of the caregivers, assistive products to ease burdens of step-climbing action are desired. The purpose of this study is to devise a mechanism to reduce caregivers’ burdens when they make wheelchairs climb steps and to develop casters with the devised mechanism. Prior to the development of the step climbing mechanism, measuring experiments of forces a caregiver apply to a wheelchair in a step-climbing action is conducted using normal casters. In reference to the result of the experiment using the normal casters, the authors devise step-climbing casters with a burden reduction mechanism. It utilizes the reaction force from the step induced by an unnecessary force applied by caregivers in a step-climbing action. Mechanical analysis of a wheelchair with the burden reduction mechanism is carried out numerically to show the effectiveness of the mechanism. Measuring experiments of forces a caregiver apply to a wheelchair in a step-climbing action is conducted using the developed step-climbing casters. The result of the analysis and the experiment indicate that the burden reduction mechanism reduces the total maximum force necessary to make a wheelchair climb a step, leading to the conclusion that the devised burden reduction mechanism is effective.

著者

鈴木 淳史 巽 和也 堀井 悟史 栗山 怜子 中部 主敬

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.853, pp.17-00200-17-00200, 2017 (Released:2017-09-25)

参考文献数

28

被引用文献数

1

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A fluid temperature measurement technique based on fluorescence polarization is developed and applied to measure the two-dimensional temperature distributions in microchannel. In this measurement method, the fluorescence depolarization due to rotational Brownian motion of the fluorescent molecules in the solution is measured and converted to fluid temperature. Since the fluorescence polarization degree is independent to fluorescence intensity, the measurement is less influenced by the fluorescence quenching effect, which is an issue in laser-induced fluorescence (LIF) method. Experiments were performed using a microchannel with fluorescent molecules solved in water. The effects of the fluorescent molecule concentration, fluid pH and fluid temperature on the fluorescence polarization degree are discussed to evaluate the influence of the quenching effects and to derive the correlation curves. Furthermore, the proposed method was applied to measure the temperature distribution with linear gradient generated in the microchannel. The results showed that the fluorescence polarization is considerably less sensitive to quenching factors compared with the fluorescence intensity measurements. A linear correlation between the polarization degree and the fluid temperature was obtained. This relationship agreed well with the theoretical one. Further, measurement of two-dimensional temperature distribution in the microchannel agreed well with the values obtained by the thermocouple measurements. These results confirmed the validity of the measurements and feasibility of the proposed method.

著者

村上 敬宜 町田 尚 宮川 進 髙城 壽雄

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.853, pp.17-00231-17-00231, 2017 (Released:2017-09-25)

参考文献数

29

被引用文献数

4

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Recently, recalls for mass production products such as car components have been frequently reported even for the case that the rate of defects is only of the order of ppm or less. The objective of this paper is to propose the solution to avoid the recall problem of the order of ppm for mass production products. Even if the defect rate is of the order of ppm or less, most of remaining safe products have to be recalled and be replaced by new components. Such a recall causes a great cost deficit if the very rare defect is possibly related to fatal accident. However, it is very difficult by the conventional quality control methods to find the defects of the order of ppm or less at the stage of design and production. This paper proposes a new practical quality control method to avoid the defects of the order of ppm or less for mass production products based on the statistics of extremes which has been successfully applied to fatigue strength evaluation of defective materials. First, several examples of the quality control method to avoid the troubles mainly caused by failures and damages of components will be presented. Next, it will be shown that the same approach also can be applied to other problems such as the optimum control of operational parameters and the selection of optimum materials through the index based on the statistics of extremes. It will be also shown that the same method can be applied not only mass production components but also to avoid the troubles and failure accidents for large machine components of small number production. The stress-strength model approach will be reviewed from the viewpoint of the statistics of extremes.

著者

江尻 英治 磯野 大樹

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.852, pp.16-00569-16-00569, 2017 (Released:2017-08-25)

参考文献数

23

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A fuel cell with a simple structure and operating at nearly ambient temperature and pressure is suitable for low cost small-sized generator sets ranging from several to tens Watts for home, outdoor and emergency use. This kind of fuel cell is called passive or self-breathing PEFC. Water management is very important and sometimes crucial for a long term stable operation in the passive type PEFC because control of gas temperature and humidity is inherently not easy for the PEFC. In this paper, various performance characteristics regarding the passive type PEFC were experimentally investigated using a rated 55 W fuel cell module with 20 cells laid out in plane. The properties, such as the output voltage of each cell, the temperature, pressure and humidity of hydrogen and air, were measured with time in the dead-end system and the recirculation system for hydrogen supply. The water balance in the fuel cell module was then calculated and the behavior of generated water, which should cause output power breakdown and voltage fluctuation in certain conditions, was also discussed. Results showed that a sudden power breakdown in a long time continuous operation with dead-end hydrogen supply system was caused by flooding in the anode and that this shortcoming was overcome by introducing a simple hydrogen recirculation system with valves and a water trap. Results also showed that 95% of produced water by the reaction was discharged from the cathode to the atmosphere in the form of vapor and that 5% trapped in the form of liquid in the hydrogen recirculation system.

著者

横山 賢介 伊藤 寛明 西宮 康治朗 長 秀雄

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.852, pp.17-00213-17-00213, 2017 (Released:2017-08-25)

参考文献数

14

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This study aims to evaluate strength of a diamond-like carbon (DLC) film on a metal for glass press molding at high temperature. Static and cyclic indentation tests at high temperature up to 300℃ with AE monitoring technique were performed. AE monitoring reveled crack generation load or cyclic number during the indentation tests. The static strength of the films at each temperature was determined from maximum stress in the film in the radial direction induced by sink-in deformation due to static indentation. The maximum stress at each temperature was estimated with indentation loads at first AE generation and FEM analysis. Thermal stress in DLC film was at each temperature also calculated. The film strength estimated by taking the thermal stresses into account was decreased with an increase of temperature. In cyclic indentation test, AE due to cracks in film was detected after 1.0×104 cycles at the load where no crack generated under one loading cycle. The cyclic number to crack initiation for the sample in 300℃ was 1/50 smaller than that in room temperature.

著者

綿引 壮真 松本 聡 阿部 豊

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.852, pp.16-00476-16-00476, 2017 (Released:2017-08-25)

参考文献数

20

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New viscosity measurement technique by using rotational breakup of electrostatically levitated droplet was developed. The new one-dimensional viscosity measurement equation is derived by integrating three-dimensional momentum equation based on the assumptions with axisymmetric shape and internal flow of levitated droplet. From the measurement result obtained, internal flow around the center of the dumbbell shape droplet is axisymmetric along the elongational axis. This result means that the present proposed new method is appropriate. In the present study, high accuracy image processing technique is applied to obtain the shape and curvature around the center of the dumbbell shape droplet by using the transformation to rotating coordinate system. The present technique can be applicable after the breakup start and before the shape of the droplet becomes asymmetric. This is reason why Euler force becomes so large that the symmetricity cannot be sustained. The newly proposed viscosity measurement technique makes it possible to estimate the viscosity within 10 % error in the range of the viscosity which the previous levitation technique cannot be available.