著者

中村 亘 河辺 徹

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 = Transactions of the JSME (ISSN:21879761)

巻号頁・発行日

vol.83, no.845, pp.15-00617, 2017-01

被引用文献数

1

---

Although PID control is still widely used in the industry, it isn't answered a high performance demand. On the other hand, the model predictive control (MPC) is paid attention as effective control but it takes much cost to introduce MPC instead of the PID control since the MPC structure quite different from the PID control. To defeat such situation, this paper proposes a model predictive PID Control method. In this method, the PID control gains are derived by solving the constrained optimization problem based on MPC algorithm without using inverse matrixes. The numerical simulations show that the proposed method is effective for various control systems.

著者

黒瀬 築 柳原 俊太郎 宮田 一司 濱本 芳徳 森 英夫

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.17-00593, 2018 (Released:2018-06-25)

参考文献数

13

被引用文献数

1

---

For the development of industrial heat pump system supplying a high-temperature heat source, the application of chevron type plate heat exchanger is being considered. In the present study, experiments and numerical simulation on flow characteristics in single chevron channel with chevron angle 30°, 45° and 65° were respectively performed. In the experiment, the pressure drop of the whole chevron channel and local pressure drops in each chevron channel were measured and path lines were also observed. Besides, numerical simulation reproduced the experimental results well. From both of the experimental and simulation results, it was confirmed that the pressure drop of the chevron channel became larger with increasing the chevron angle due to the strong mixing of fluids in the respective furrows of adjacent chevron plates especially in the high chevron angle channel. In such the high chevron angle channel, velocity and pressure drop gradient distributions were almost uniform in the channel width direction normal to main flow. While, in the small chevron angle channel, the fluids mixing between furrows of adjacent plates was weak and the velocity and pressure drop gradient distributions were markedly large in the width direction. Furthermore, it was found that large pressure drops occurred in the inlet and outlet regions where the channel had flow width expansion and contraction, respectively. The large pressure drops in the inlet and outlet regions affected the overall pressure drop in the chevron channel, especially in the low chevron angle channel. For each chevron angle channel, the local friction factor was obtained and the loss coefficient for the flow expansion and contraction at inlet and outlet regions was determined. Based on these results, the prediction method of overall pressure drop in the chevron channel was proposed.

著者

高野 悠一郎 長濱 大空 小山 弘貴 宮坂 明宏

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.862, pp.17-00498, 2018 (Released:2018-06-25)

参考文献数

8

---

In order to achieve advanced missions, it is necessary to develop satellite with large aperture reflectors. Tension truss structure is effective for reducing the weight of the antenna. However, the total strain energy of the cables increases with the number of cables. Consequently, a support structure must be sufficiently rigid to prevent deformation of the surface. The reduction of the reflector's weight can be achieved if the tensile force of the cables decreases, while maintaining the required surface accuracy. Therefore, a surface design method in which compression members are located on the cable network instead of tension cables had been proposed. It was found that cable tension can be decreased within the required surface accuracy based on an analytical estimation. However, the cable tension can be changed after an adjustment of the surface accuracy to eliminate manufacturing and assembling errors. In this study, we evaluate the effectiveness of the proposed method based on an experiment including an adjustment of the surface accuracy. We measure the surface accuracy and reaction force from a support structure using assembled cable-network models. As a result, the total cable strain energy of the cable network with compression members can be decreased by half of that without compression members.

著者

野間口 大 中切 拓 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.853, pp.17-00122, 2017 (Released:2017-09-25)

参考文献数

22

被引用文献数

4

---

Generation of new concepts in product design process serves as driving force of innovation. While many methods have been proposed for supporting design concept generation, it has rarely been supported in a systematic way, because its process is done in designer's implicit thought, and therefore, it is difficult to explicitly formalize the process. This paper proposes a model of designers' thinking process in concept generation called ECF cycle. It consists of three steps, i.e., (1) Externalization: the step for representing design concepts with drawings and language, (2) Classification: the step for classifying concepts with function trees, and (3) Finding voids: the step for finding potentials of new concepts called void, which is a defect of the classification. Then, this research builds a new method of concept generation incorporating the theory of solving inventive problems (TRIZ). The method is based on a quick reference table of TRIZ principles, which helps designers to create a new concept corresponding to a void found by ECF cycle. A case study of concept generation of new running shoes is demonstrated in order to verify the ability of the proposed method.

著者

大川 真弥 滝田 好宏 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 (ISSN:21879761)

巻号頁・発行日

vol.80, no.812, pp.TRANS0076-TRANS0076, 2014 (Released:2014-04-25)

参考文献数

12

被引用文献数

1 3

---

This paper proposes a brush-cutting robot which can cut high weeds and grass automatically by hand-held brush-cutter sold in hardware store. The robot vehicle is constructed with a center articulated body, a manipulating mechanism of the brush-cutter, motor controller and sensors for self-localization. In order to get its own position continuously, two Laser Range Finders (LRF), a GPS campus and odometry encoder for each wheel are installed. Authors proposed Sensor Steering Mechanism (SSM) for the lateral guided vehicle with steering mechanism. This robot is applied SSM for the center articulated body to follow the way point line on the 2-D map. The map for self-localization is constructed with a 0.1m by 0.1m grid that is measured by the 3-D LRF. The experimental set up was developed and installed in the control program and then autonomous mowing was tested, leading to the results of running and mowing in the quadrangle of the No. 4 building of science and engineering at National Defense Academy. As a result, the proposed system achieved an error of 0.2m or less for the way point line following performance. The developed brush-cutting robot successfully completed the work without untreated area by providing an appropriate overlap by the result.

著者

新木 悠斗 上道 茜 山﨑 由大 金子 成彦

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.17-00507-17-00507, 2018 (Released:2018-05-25)

参考文献数

8

---

As a method for mining offshore gas fields, a floating production, storage and offloading (FPSO) system is attracting attention. However, sloshing in the oil-gas separator installed in FPSOs excited by sea waves is expected to cause significant difficulties. To suppress sloshing wave heights, one possibility may be to install perforated plates in a tank. In this study, a method is proposed for the accurate estimation of the first resonant wave height in the horizontal cylindrical tank with a perforated plate under pitching excitation in less time. To accomplish this purpose, the pressure loss due to the perforated plate in the open channel must be estimated accurately. Therefore, the pressure loss is modeled using steady CFD calculations considering the effects of the distribution of the flow velocity and the distribution of the inflow angle. The first order sloshing wave height is calculated in the theoretical analysis by substituting the pressure loss calculated in steady CFD. The wave heights determined using the pressure loss utilized by steady CFD are compared with the experimental value measured with a small-scale model. Using the method proposed in this study, the first resonant wave height of sloshing wave height is calculated accurately in less time.

著者

嵯峨 宣彦 手銭 聡 佐藤 俊之 永瀬 純也 遠藤 匠

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.17-00548-17-00548, 2018 (Released:2018-05-25)

参考文献数

28

被引用文献数

3

---

In disaster areas, rescue work by humans is extremely difficult and dangerous. Therefore, rescue work using rescue robots in place of humans is attracting attention. This study specifically examines peristaltic crawling, the movement technique used by earthworms, because it can enable movement through narrow spaces and because it can provide stable movement even in various difficult environments. Moreover, we designed each part of the robot based on required specifications and developed a real robot. We present results of motion experiments conducted with robot movement on level ground.

著者

松川 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.84, no.858, pp.17-00358-17-00358, 2018 (Released:2018-02-25)

参考文献数

31

---

In the present study, flow in an ion-drag electrohydrodynamic (EHD) micropump was numerically simulated, and electric charge density on the emitter was modeled through the simulation. The simulation was performed for an ion-drag EHD micropump developed and experimentally tested by Kazemi et al. (Journal of Microelectromechanical Systems, Vol.18, No.3 (2009), pp.547-554.). Two models of charge density on the emitter were tested. First, one model was tested in which charge density was distributed uniformly on the emitter. The simulated discharge pressure generated in the micropump was proportional to both applied voltage and charge density. The experimental discharge pressure was reproduced by considering the change of charge density with applied voltage. Next, the other model was tested in which charge density was distributed depending on electric field on the emitter. The model was more realistic than the former because of consideration of electric field distribution on the emitter. The model also reproduced the experimental discharge pressure.

著者

日野 遥 杉本 大己 高橋 優輔 橋本 成広

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.17-00202-17-00202, 2018 (Released:2018-02-25)

参考文献数

16

---

Mechanical stimulation affects cell behaviors (proliferation, orientation, migration and differentiation) in vivo, and a lot of models of experiments on mechanical stimulation in vitro have been reported. The development of control technique on cell is important in the field of regenerative medicine. Recently, skeletal myoblasts have been applied for cardiac repair. In the previous study, C2C12 (mouse myoblast cell line) made orientation perpendicular to the streamlines in the donut shape flow channel. In the present study, C2C12 has been cultured in the Couette type of the shear field between the rotating disk and the stationary culture plate to study quantitatively the effect of shear stress (for 24 hours, < 2 Pa) on orientation of myoblasts in vitro. The time lapse image of myoblasts shows that C2C12 tilts perpendicularly against the flow direction at the wall shear stress of 2 Pa and that C2C12 tends to migrate to the lower wall shear stress region of 0.4 Pa.

著者

釜谷 昌幸

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.83, no.856, pp.17-00316-17-00316, 2017 (Released:2017-12-25)

参考文献数

20

---

This study is aimed at applying the performance-based maintenance (PBM) concept to determine inspection schedule. Previously, the time-based maintenance concept has been applied to determine the inspection schedule for nuclear plant components. In the PBM concept, frequency of inspection is determined by operation time before the inspection. Duration before the next inspection is extended if the component indicates no cracking for a long time. In this study, the change in structural reliability due to applying the PBM concept was investigated by probabilistic fracture mechanics analyses. In order to calculate the probability of leakage or fracture (failure probability), growth of fatigue cracks initiated at the primary coolant pipe of pressurized water reactor nuclear power plants was simulated considering variations in yield and tensile strengths, fatigue crack growth rate, initial crack shape and so on. It was demonstrated that the failure probability was reduced by performing inspections according to the time-based maintenance concept. Frequency rather than detectability of inspection had a larger impact on reducing the failure probability. It was shown that, by applying the PBM concept, the number of inspections could be reduced significantly without increasing the failure probability. It was concluded that the PBM concept could optimize the inspection schedule.

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

---

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

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

---

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

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

---

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

---

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

---

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

---

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

---

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

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

---

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.