著者

Hirotsugu INOUE Minoru KAMIBAYASHI Kikuo KISHIMOTO Toshikazu SHIBUYA Takashi KOIZUMI

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME international journal. Ser. 1, Solid mechanics, strength of materials (ISSN:09148809)

巻号頁・発行日

vol.35, no.3, pp.319-324, 1992-07-15 (Released:2008-02-18)

参考文献数

6

被引用文献数

5 5

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The Laplace transform is known as one of the most useful mathematical tools for solving a wide range of engineering problems. For its application to theoretical or numerical analyses, methods of numerical inversion have been studied extensively. On the other hand, the method of numerical transformation has not yet been studied very much. This is one of the reasons why few applications of the Laplace transform to experimental analysis have been reported. In the present paper, a method for numerical Laplace transformation and inversion utilizing the fast Fourier transform (FFT) algorithm is studied with the intention of applying it to experimental analysis. A discrete Laplace transform pair is formulated as in the discrete Fourier transform pair. The numerical accuracy of the present method is evaluated for the sinusoidal function and step function. A chart is presented for determining parameters for computation so as to attain a specified accuracy.

著者

Koji MIYAJI Hiroto TAKEGAWA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Fluid Science and Technology (ISSN:18805558)

巻号頁・発行日

vol.17, no.2, pp.JFST0004, 2022 (Released:2022-07-13)

参考文献数

21

---

A new computation method to predict a transonic wing flutter under the limit-cycle oscillation (LCO) is developed using the time spectral (TS) method. The fluid and structural unknowns at a specified time interval in one cycle of the flutter are obtained by steady-state solutions of the aeroelastic TS equations, and thus higher computational efficiency is expected. Determining the frequency is the key for the flutter prediction, and we propose a method of minimizing the residuals of the fluid equation. The time histories of the plunge and pitch are reconstructed by the discrete Fourier transform, and compared with the existing time marching (TM) method. The effects of the number of harmonics in the TS and the time-step size in the TM are examined for the detailed comparison. The frequency, amplitude, and phase differences between the structural vibration modes all well agree between the two methods for a wide range of flutter speed index. Complex flutter boundaries are also predicted. The TS method is faster to reach the LCO than the TM method for the first vibration mode of the flutter. It is slower for the second vibration mode, but the increase in the computation time is much smaller than the reduction in the first mode. In general, the TS method is particularly advantageous for the prediction near flutter boundaries and is useful for aircraft design.

著者

Byeongil KIM Yushin CHANG Man Hyung LEE

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME International Journal Series C Mechanical Systems, Machine Elements and Manufacturing (ISSN:13447653)

巻号頁・発行日

vol.49, no.4, pp.1048-1057, 2006 (Released:2007-06-15)

参考文献数

12

被引用文献数

17 26

---

For a maneuvering unmanned autonomous helicopter, it is necessary to design a proper controller for each flight mode. In this paper, the overall helicopter dynamics is derived and a hovering model is linearized and transformed into a state-space form. However, since it is difficult to obtain parameters for stability derivatives in the state-space directly, a linear control model is derived by a time-domain parametric system identification method with real flight data of a model helicopter. Then, two different controllers (a linear feedback controller with the proportional gain and a robust controller) are designed and their performances are compared. The simulation results show outstanding performance. The validated controllers can be utilized to enable autonomous flight of a RUAV (Rotorcraft-based Unmanned Aerial Vehicle).

著者

Yuya BABA Fumiteru AKAMATSU Masashi KATSUKI

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME International Journal Series B Fluids and Thermal Engineering (ISSN:13408054)

巻号頁・発行日

vol.47, no.4, pp.750-760, 2004 (Released:2005-05-15)

参考文献数

22

---

The numerical methods of CIP (Cubic Interpolation Pseudo-particle/Propagation) and C-CUP (CIP Combined Unified Procedure) are appropriate and numerically robust even in the direct simulation of turbulent combustible flows. Although these methods have many advantages in the numerical procedure, their accuracy and characteristics have not been evaluated in detail. In the present study, the ability of CIP was firstly examined by comparing it with classical methods in a direct numerical simulation of incompressible turbulent flow. Secondly, C-CUP was evaluated by direct simulations of a compressible-fluid, single-vortex convection problem and of the Aeolian tone. In the first cases, CIP was inferior to the classical method in the vortex shape reproduction. In the latter case, C-CUP showed an advantage in suppressing unrealistic pressure increase and satisfactorily simulated the sound pressure distribution. Furthermore, CIP and C-CUP were applied to numerical simulation of spray combustion in conjunction with applying classical methods in order to compensate the inferior points of CIP.

著者

Yu MORIWAKI Nobuo SAKAI Yoshinori SAWAE Teruo MURAKAMI

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.4, no.1, pp.153-164, 2009 (Released:2009-05-12)

参考文献数

10

---

The human forearm with elbow joint has two degrees of freedom of motion. Especially it is noticed that the wide range for the rotation of the forearm (pronation-supination) is attained according to the sophisticated complexity of the human forearm with elbow joint. The elucidation of its movement mechanism is useful for the functional evaluation for the medical treatment and application to the welfare devices for the upper limb. The purpose of this study is to develop the arm model that functionally mimics the musculoskeletal system of the human forearm with elbow joint. In this paper, we made a physical model and the computational models, which replicate the bionic function of the forearm with elbow joint. By estimating the moment arms in a physical model, the mobility of the simplified physical model was evaluated. In the three-dimensional computational forearm bone models different in the geometry, the beneficial property of the centroidal lines of the bones was confirmed to extend the range of motion for the pronation-supination.

著者

Juhachi ODA Jiro SAKAMOTO Kenichi SAKANO

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME International Journal Series A Solid Mechanics and Material Engineering (ISSN:13447912)

巻号頁・発行日

vol.49, no.3, pp.390-396, 2006 (Released:2007-01-25)

参考文献数

6

被引用文献数

30 44

---

A woodpecker strikes its beak toward a tree repeatedly. But, the damage of brain or the brain concussion doesn’t occur by this action. Human cannot strike strongly the head without the damage of a brain. Therefore, it is predicted that the brain of a woodpecker is protected from the shock by some methods and that the woodpecker has the original mechanism to absorb a shock. In this study, the endoskeltal structure, especially head part structure of woodpecker is dissected and the impact-proof system is analyzed by FEM and model experiment. From the results, it is obvious that the woodpecker has the original impact-proof system as the unique states of hyoid bone, skull, tissue and brain. Moreover it is considered that woodpecker has the advanced impact-proof system relating with not only the head part but also with the whole body.

著者

山内 庄司 中西 重康 石谷 清幹

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.47, no.416, pp.693-702, 1981

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蒸発管内密度波振動(流れ逸走を含む)の安定限界に対し, 各種因子が及ぼす効果について, 広範囲に解析的に検討した. 圧力降下一定の均一加熱管を対象に, 均質流モデルを用いて解析し, 7個の無次元パラメータによるスケーリングが可能であることを示した. また, 基礎式を線形化, ラプラス変換して得た特性方程式を用いて, ラプラス平面の虚軸をパラメータ空間に写像(ネイマルクのD分割法)することにより, いくつかのパラメータ平面で安定限界の形状を示した. 特に線形パラメータ面上では, D分割境界線の形状に双曲線状のものとだ円状のものがあり, 前者では, 安定限界は対応する漸近線にほぼ一致することを示した. また蒸発管内流動時間と安定限界振動数との関係についても検討し, 奇数次の振動が可能なこと, 本モデルでは極端な例を除いて基本振動が最不安定であることなどを示した

著者

Mai NONOGAWA Seigo NAKAYA Masashi ISOBE Kenzen TAKEUCHI Hideyuki AZEGAMI

出版者

The Japan Society of Mechanical Engineers

雑誌

Mechanical Engineering Journal (ISSN:21879745)

巻号頁・発行日

vol.8, no.5, pp.21-00200, 2021 (Released:2021-10-15)

参考文献数

29

被引用文献数

1

---

This study presents methods to develop a three-dimensional numerical foot model and to identify the loading condition that is used to design a stable sole for running shoes. In a previous study, the authors proposed a method to optimize the shape of the sole to increase stability while maintaining the cushioning property. In the problem formulation, the loading condition was given as a boundary force distributed on the top surface of the sole. The aim of this study is to replace the loading condition with the force and moment at the origin of the ankle joint coordinate (AJC) system by modeling a foot with a finite element model. A finite element model of a foot is constructed using X-ray CT image data, and consists of bony structures, soft tissue, and plantar fascia. The plantar fascia is set at the bottom of the bony structures. The force and moment used in the finite element analysis are identified by inverse dynamic analysis using an experimental measurement in the practical operation of the ground reaction force (GRF) when the GRF in the direction of the foot length becomes minimum. In the finite element analysis, the finite deformation containing the contact condition between the bottom surface of the foot and the ground representing a sole made of resin is considered. For an index of the shoe stability, we define a heel eversion angle (HEA) by the rotational angle of the heel with respect to an axis in the foot length direction and evaluate it by finite element analysis. The validity of the finite element foot model as well as the force and moment obtained in this study are confirmed based on the agreement in the HEA results between the experiment and finite element analysis.

著者

Motomu NAKASHIMA Shun MAEDA Takahiro MIWA Hiroshi ICHIKAWA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.7, no.2, pp.102-117, 2012 (Released:2012-03-13)

参考文献数

32

被引用文献数

26 25

---

In this study, the optimal arm strokes in crawl swimming which maximize the swimming speed and propulsive efficiency were solved computationally. For this objective, an optimizing method which consisted of the random search and the PSO (Particle Swarm Optimization) algorithm was constructed. In order to consider the muscle strength characteristics of the swimmer as the constraint condition of the optimization, an experiment to measure the maximum joint torques was carried out for various joint angles and angular speeds. Using the measured experimental data as the reference values, a musculoskeletal simulation model was constructed. By the constructed musculoskeletal model, muscle strength characteristics in various conditions were investigated and used to create a database. Using this database, the optimizing calculation was finally conducted and the following results were obtained: In the optimization maximizing the swimming speed, the swimming speed became maximum when the stroke cycle was 0.9 s. A relatively I-shaped stroke was obtained in this case. In the optimization maximizing the propulsive efficiency, the propulsive efficiency became maximum when the stroke cycle was 1.3 s. A relatively S-shaped stroke was obtained in this case. Two strokes which respectively maximized the swimming speed and propulsive efficiency were very similar to each other when the stroke cycles were the same. The swimming speeds and stroke cycles obtained in the optimizing calculation were within reasonable ranges compared to the actual races.

著者

Masato YAMAGISHI Yusuke YAHAGI Masanori OTA Yusuke HIROSE Shinsuke UDAGAWA Tatsuro INAGE Shigeya KUBOTA Koji FUJITA Kiyonobu OHTANI Hiroki NAGAI

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Fluid Science and Technology (ISSN:18805558)

巻号頁・発行日

vol.16, no.3, pp.JFST0021, 2021 (Released:2021-10-01)

参考文献数

16

被引用文献数

4

---

Three-dimensional density measurement of unsteady flow field around a projectile (φ = 8mm) is carried out in the ballistic range at Institute of Fluid Science, Tohoku University. The purpose of this study is to obtain the density distribution including its wake region in non-axisymmetric unsteady flow. The projectile’s Mach number in the experiment is 1.35. Simultaneous multi-angle BOS measurement system using twelve digital cameras and pulsed LEDs is installed in the test chamber of the ballistic range. The Color-Grid Background Oriented Schlieren (CGBOS) technique is used in the measurement system to obtain the projection data of density gradient. Algebraic Reconstruction Technique (ART) method and Successive Over Relaxation (SOR) method are used to obtain the density distribution from projection data. To improve the accuracy of 3D reconstruction, we evaluate the view-angle of the measurement system in the present study. The result shows that the bow shock, expansion wave and recirculation zone can be confirmed by the proposed method. However, bow shock in each method are thicker than the schlieren image due to the blur of the CGBOS images. Even then, the 3D shape of density distribution reconstructed by proposed method can be reliable, and the relative error of obtained density between the theoretical value for normal shock relation is about 5% at the bow shock.

著者

岡本 和也 山口 健吾 丸 典明

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.72, no.718, pp.1840-1847, 2006

被引用文献数

3

---

We propose a method for following motion control of the mobile robot by using Linear Visual Servoing (LVS). Following motion control is realized by the following motion of the body to the target object keeping a desired distance. Following motion control by using LVS is based on linear approximation of the transformation between binocular visual space and motion space of the mobile robot. Motion space is defined by translational velocity and rotational velocity of the robot coordinate system which is attached at the center of gravity of the mobile robot. Some experimental results are presented to demonstrate the effectiveness of the proposed method.

著者

Yohei HAZAMA Hitoshi IIMA Yoshiyuki KARUNO Kosuke MISHIMA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Advanced Mechanical Design, Systems, and Manufacturing (ISSN:18813054)

巻号頁・発行日

vol.15, no.6, pp.JAMDSM0069, 2021 (Released:2021-10-15)

参考文献数

33

被引用文献数

11

---

In recent years, efficient logistics has become indispensable, and using unmanned aerial vehicles (UAVs) or drones is promising for considerably reducing the cost and time required for parcel delivery. This paper addresses a parcel delivery scheduling problem. In this problem, a truck loaded with drones and parcels leaves a distribution center and stops at some points on a fixed route. At each point, the drones take off and deliver parcels to customers. We define this problem as finding the assignment of customers to both the drones and their takeoff points. Then, we propose a genetic algorithm (GA) for finding a near-optimal solution in a short time. In the proposed GA, a solution is represented using sets of customers assigned to the takeoff points, and a heuristic rule determines the assignment to the drones. The crossover operation enables offspring to inherit the customer sets. Experimental results show that the proposed GA can successfully find an optimal or a near-optimal solution faster than an integer programming solver for almost all instances. In addition, it significantly outperforms other GAs using a different crossover.

著者

F.A. Williams

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会誌 (ISSN:24242675)

巻号頁・発行日

vol.98, no.920, pp.535-536, 1995-07-05 (Released:2017-06-21)

被引用文献数

1 1

著者

Shin'ichiro KANOH Ko-ichiro MIYAMOTO Tatsuo YOSHINOBU

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.5, no.1, pp.32-40, 2010 (Released:2010-01-29)

参考文献数

8

被引用文献数

9 14

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An auditory brain-computer interface (BCI) which detects event-related potentials (ERPs) elicited by selective attention to one of the tone streams was proposed. Two frequency oddball tone sequences with different tone frequency ranges were alternately presented to subjects, and were perceived by subjects as two kinds of segregated streams. Event-related potentials elicited by two kinds of deviant tones were classified by linear discriminant analysis (LDA) to find the stream subjects paid selective attention to. Experiments with six subjects have shown that this system could realize binary selection from two tone streams.

著者

Hideki TODA Takeshi MATSUMOTO Shin SUGIHARA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Advanced Mechanical Design, Systems, and Manufacturing (ISSN:18813054)

巻号頁・発行日

vol.13, no.2, pp.JAMDSM0034, 2019 (Released:2019-05-14)

参考文献数

24

被引用文献数

4 4

---

In this paper, to mechanize a human ankle joint stretching treatment that is mainly performed by a PT (Physical Therapist), the geometrical relationships among the Ankle joint, Hip joint, Sole, and pushing device rotation center are analyzed using a simple numerical calculation model, and the effectiveness of the model was examined in an actual developed system. The stretching of the ankle joint is an important medical treatment that PTs perform to help their patients to recover their ability to walk and to prevent contracture. Because the ankle joint treatment requires a large amount of force (equal to the subject’s weight) and precise angle control at the same time, manual treatment by PTs has not been replaced by mechanical treatment systems. In a previous study, we developed a new mechanism of ankle joint stretching that involves fixing the length of the subject sitting chair and the device; the novel mechanism can realize comfortable stretching without pain. However, the optimum geometrical relationships among the Ankle joint, Hip joint, Sole, and pushing device rotation center have not been analyzed. In this paper, to develop the effective mechanism of the stretching treatment, the geometrical relationships were analyzed mathematically by using numerical calculation, and the effectiveness of the numerical calculation was confirmed by manufacturing a treatment device comprising two force sensors and two DC motors based on the calculation results. Numerical calculation results show that the PT’s key point of the ankle joint treatment was a position located between the Ankle joint and the pushing device rotation center. The analytical result will effectively promote the development of the mechanical systems used as ankle joint stretching treatment devices.

著者

Sudarmanto Budi NUGROHO Akimasa FUJIWARA Junyi ZHANG

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME International Journal Series B Fluids and Thermal Engineering (ISSN:13408054)

巻号頁・発行日

vol.49, no.1, pp.8-18, 2006 (Released:2006-08-15)

参考文献数

17

被引用文献数

2 2

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Jakarta city has serious air pollution problems which largely affected by transportation activities. In this paper, a comparative analysis of ambient roadside air pollution patterns in Jakarta city was conducted by using time series data at the existing roadside monitoring stations in 2003. The complex cause-effect relationships between meteorology and pollutants, thus, differ from one season to another. This paper attempts to apply structural equation models with latent variables, which represents the above-mentioned cause-effect relationships. The effectiveness of the established models is empirically confirmed that the goodness-of-fit indices are 0.783 for the weekday wet, 0.845 for the weekday dry, 0.775 for the weekend wet, and 0.822 for the weekend dry. The models give us a better way to analyze urban air pollution due to the results of the significant interactions among meteorological factors, wind and primary pollutants, and also their different influences on surface ozone for each season.

著者

Takeo KAJISHIMA Satoshi TAKIGUCHI Hiroyuki HAMASAKI Yutaka MIYAKE

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME International Journal Series B Fluids and Thermal Engineering (ISSN:13408054)

巻号頁・発行日

vol.44, no.4, pp.526-535, 2001 (Released:2002-09-27)

参考文献数

24

被引用文献数

164 215

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Turbulence modulation in particle-laden flow, especially the influence of vortex shedding, was investigated by means of the direct numerical simulation. To this end, we developed a finite-difference scheme to resolve the flow around each particle moving in turbulence. The method was applied to the flow around a sphere and the accuracy was confirmed up to the Reynolds number range with vortex shedding. The agreement between our 4th-order central finite-difference method and spectral method for turbulent channel flow without particles was also fine. Then, we simulated upward flow in a vertical channel including solid particles. The velocity and vorticity fluctuations as well as Reynolds shear stress were strongly affected by wakes from particles. The shed vortices were elongated in the mainstream direction by the velocity gradient and resulted in the hairpin vortices. They increased the energy production rate in couple with production due to particle-turbulence correlation.

著者

Masao WATANABE Takahiro SHIMIZU Ryo TAKAGI

出版者

The Japan Society of Mechanical Engineers

雑誌

The Proceedings of International Symposium on Seed-up and Service Technology for Railway and Maglev Systems : STECH (ISSN:24243167)

巻号頁・発行日

pp._3D23-1_-_3D23-8_, 2015-11-09 (Released:2017-06-19)

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Urban railway lines, upon which large conurbations crucially depend, suffer from chronic congestion and prolonged travel times during peak hours, and improvement of capacity and reduction in travel times are desperately needed. Also, competition with other modes of transport is ever intensifying. These necessitate the realization of a very high performance railway, called in this paper as "ultra-convenient rail transport" (UCRT), which can provide services that much better fit individual passengers' needs. Because needs of the passengers are very diverse, so should the services provided by UCRT. This naturally leads to the conclusion that ultra-high frequency operation is essential for UCRT. In this paper, the authors present the discussions on possible new technologies that can be used to realize UCRT, and the impact they may have on the attractiveness of the services provided by the new railway system. The techniques upon which the authors would discuss in this paper are: (1) moving block signalling systems, (2) on-board turnouts and (3) soft coupling. In the discussion, the pure moving block system (PMB) which stands inside the so-called 'brick wall' assumption and the relative moving block system (RMB) that breaks the 'brick wall' assumption are compared, and significant improvements in performance may be achieved when RMB is combined with on-board turnouts. These techniques contribute to further reduction of headways between trains, and thus contribute to the realization of UCRT.

著者

Katsuhiko SANDO Takeshi YAMAMOTO Kenji SAWADA Tomoyuki TANIGUCHI Nobuyuki SOWA Haruki MORI Takahiro KONDO

出版者

The Japan Society of Mechanical Engineers

雑誌

Mechanical Engineering Journal (ISSN:21879745)

巻号頁・発行日

pp.20-00497, (Released:2021-03-03)

参考文献数

11

被引用文献数

1

---

This paper describes a design method of a friction reducer device using a loading cam to suppress unstable vibration. Nonlinear simulation and energy analysis of numerical solutions demonstrates that destabilization is caused by the large phase difference between the slipping velocity in the translation direction and that in the rotation direction. It was found that similarly unstable vibration occurs in various structures using wedge rollers with translational and rotational motion. The analytical equation could be simplified by focusing on the motion factor that affects the slip velocity of the power transmission surface, which is the factor of vibration. Consequently, the design method for suppressing vibration could be expressed by a mathematical formula. This equation is validated by using the results of experiments conducted in the previous work of the current authors. Furthermore, from this equation, we proposed that vibration could be suppressed by the parameter balance of the power transmission device without using damping. The power transmission surface slips when a quick torque is input and damping is used. The proposed design can handle a quick torque response and reduce the weight of the reducer. Specifically, the shape of the wedge roller is made lighter, so that the moment of inertia of the roller is not lowered, or the wedge roller is set as a small roller.

著者

Masaaki MOTOZAWA Yoshiyuki MATSUMOTO Tatsuo SAWADA

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME International Journal Series B Fluids and Thermal Engineering (ISSN:13408054)

巻号頁・発行日

vol.48, no.3, pp.471-477, 2005 (Released:2006-02-15)

参考文献数

14

被引用文献数

4 4

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Experimental results for the properties of ultrasonic propagation velocity in kerosene-based and water-based magnetic fluids are reported. Ultrasonic wave frequencies of 1MHz, 2MHz and 4MHz are used and the measurement scheme is based on the pulse method. The external magnetic field intensity is varied from 0mT to 550mT and the angle between the magnetic field direction and the direction of ultrasonic wave propagation is varied from 0° to 90°. The ultrasonic propagation velocity in magnetic fluids is dependent on temperature, elapsed time of applying the magnetic field, and magnetic field intensity. Hysteresis and anisotropy of ultrasonic propagation velocity are observed. These interesting results seem to be related to chain-like cluster formation in the magnetic fluids and the characteristic period of Brownian motion of the magnetic particles.