Transactions of the Japan Society of Mechanical Engineers Series C
Online ISSN : 1884-8354
Print ISSN : 0387-5024
Current issue
Displaying 51-85 of 85 articles from this issue
  • Takafumi SUZUKI, Masaki TAKAHASHI
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3567-3576
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    This paper presents a real time collision avoidance method considering robot's size for an autonomous omni-directional mobile robot by simultaneous control of translational and rotational motions. This method enables the robot, which the size of width is not equal to that of length, to avoid unknown obstacles safely and efficiently in real time. To consider the difference between the width and length of the robot, the Capsule Case is newly introduced. In order to achieve the simultaneous control, this method employs an omni-directional platform. As an example of design method of the proposed method, novel control method based on the Fuzzy Potential Method is proposed. To verify the effectiveness of the proposed method, several numerical simulations and experiments are carried out.
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  • Osamu NISHIHARA
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3577-3586
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
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    Real-time optimizations of the lateral and longitudinal tire force distributions based on tire workloads are investigated. In previous studies, the authors realized minimax optimizations for several configurations of independent steering vehicles; these were realized by employing numerically robust combinations of an algebraic approach, the bisection method, and the golden section method. The purposes of this study are to investigate the applicability of optimality condition approach to minimax optimization and to consider the exploitation of complementarities between lateral forces and longitudinal forces in yaw-moment generation to further reduce the objective function. The problem for independent four-wheel steering is introduced, and the assumption of equivalent tire workload leads to a simple equation as the first optimality condition. Complementarities between the lateral and longitudinal forces provide another degree of freedom. A similar formulation and an additional optimality conditions provide stable convergence by the Newton-Raphson method. The exact optimum solution to the basic problem is obtainable by the enumeration of nine possible tire force distribution patterns.
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  • Akira OHMURO, Yoshikazu HATTORI
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3587-3594
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
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    This paper discusses an obstacle avoidance problem in vehicle maneuvering. For the avoidance of collision, an optimal control method minimizing the longitudinal movement was proposed. In this method, however, the optimal trajectory is effective for the emergency avoidance primarily. Therefore, an optimal control problem is formulated as minimizing the maximum of the resultant vehicle force by using the relative distance and velocity between vehicle and obstacle. It is shown that an optimal input-map in a 2-dimensional space is derived for online controller of vehicle.
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  • Takamasa NAIKI, Takashi KUBOTA
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3595-3602
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
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    In planetary missions, rovers that can traverse over rough terrain are required in order to explore craters and slopes which have high scientific value. Rovers with wheeled locomotive system are used broadly in planetary missions, because the wheeled locomotive system has low energy consumption and its configuration is simpler than other types of locomotive system, such as the tracked locomotive system. However, wheeled robots have low traversability. In order to solve this problem, various methods have been developed. For example, the rocker bogie suspension is one of the most well-known methods to improve traversability. Sojourner and MER have a rocker-bogie suspension that has worked successfully on Mars. To traverse over more challenging terrain, however, passive suspension is inadequate. Recently, several rovers with active suspension have been studied. In this paper, the authors propose a new mobility system with active suspension, which has high efficiency and high traversability. The simulation results show the effectiveness of the proposed mobility system in its ability to climb slopes and its stability from tip over when traversing various rough terrain using active suspension.
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  • Yuuki ISHIMORI, Takanori FUKAO, Hitomu SAIKI, Takashi KOHNO
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3603-3611
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    The establishment of the information gathering system is important for the rescue activity. To collect the information, it is useful to use a blimp, because of its low-sky availability, safety and long flight. This paper proposes a control design method for automatic landing of an outdoor blimp robot. This is important for the information-gathering system by an outdoor blimp robot to be put to practical use. The landing control consists of stabilizing control in horizontal plane and vertical control. The stabilizing control is designed by using H_∞ control. The vertical control is composed of control of altitude and pitching motion. Some simulations and experiments are performed in evaluation of the control performance. As a result, the outdoor blimp robot showed a sufficient control performance of automatic landing.
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  • Nobutaka WADA, Masayuki MINAMI, Masami SAEKI, Masaharu NISHIMURA
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3612-3621
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
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    In this paper, a tracking control problem in the presence of actuator saturation is addressed. Firstly, a control law that guarantees both closed-loop stability and asymptotic convergence of the tracking error in the case of a constant reference signal is introduced. The feedback gain of the control law is adjusted, at each sampling time, so that both large region of attraction and fast convergence of the tracking error are achieved. Secondly, based on the control law, a control algorithm that can be used for arbitrary time-varying reference signals is proposed. The most important feature of the proposed control algorithm is that the overshoot of the plant output can be effectively attenuated. Moreover, the effectiveness of the proposed control algorithm is shown through experimental results.
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  • Tomoki TAJIRI, Rei OGAMI, Kazuya SUGIMOTO, Yogo TAKADA, Tomoyuki WAKIS ...
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3622-3629
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Recently, humanoid robots have widely researched, and they have become possible to be controlled robots with complicated kinetic characteristics. However, in the cases that the robot walks on an unknown undulating road or receives disturbances such as collision with an object from the outside, the robot loses stability and falls even if the inverted pendulum model is used. In this paper, an impedance control of a swing leg and a PI control of the rotation of a humanoid robot's waist are used to stabilize the dynamic walk on the unknown undulating road. For an impedance control, force sensors on the soles of the humanoid robot are used to measure the torque and force of a swing leg that collide with the unknown undulating road. An angular velocity sensor and acceleration sensor in the body of the humanoid robot are used to measure the rotation of the waist and its error signal are used for the PI control of humanoid robot motion. As a result, it has been confirmed that the humanoid robot can walk on an unknown undulating road with proposed walking method.
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  • Masahiro SHINGU, Kiyoshi EGUCHI, Yoshiyuki SANKAI
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3630-3639
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Polio survivors with severe limb paralysis cannot move their limbs voluntarily because they have a significantly reduced number of motor neurons due to the poliovirus infection. There is a danger that their ability to control their neuromuscular system, in particular fundamental abilities such as balancing flexors and extensors in the neuromuscular system may decrease dramatically in the long-term. If such polio survivors could improve their ability to balance, it would be possible for them to use the "Robot Suit HAL" wearable movement support device. HAL anticipates its wearer's intended movements through the measurement of bioelectrical signals, and generates assistive torques to support their movements. This study proposes a biofeedback training method using visual information, with the objective of restoring motor functions using HAL. A biofeedback system that feeds-back bioelectrical signals visually was developed, and tested with a polio survivor. The polio survivor was able to adjust the balance of their muscular control through the proposed training method, and voluntary motion was recorded to a paralyzed knee using a single-joint type HAL. These results suggest that polio survivors who have been paralyzed for a long time may improve their ability to control their neuromuscular system by using the proposed training method.
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  • Masanori GOKA, Hiroyuki NAKAMOTO, Satoru TAKENAWA, Yasuaki KIDA
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3640-3647
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    We have proposed a novel magnetic type tactile sensor that can measure a three-axis force and detect slips. Its simple structure comprises two layers, an elastic layer, and a substrate layer. The elastic layer is made of an elastic material and has a cylindrical permanent magnet. The substrate layer is a glass epoxy board and has four GMR (giant magneto resistance) elements. Features of this sensor are a wiring reduction, simple structure and low cost. This sensor can be created with many variation in hardness and shape of elastic layer. In this paper, our purpose is producing downsized tactile sensor in order to realize a low cost and high-performance robot hand. Therefore, we are going to design the tactile sensor using finite elemental method for estimation of the size of the elastic layer and the arrangement of electric parts. We then verify the performance of this downsized sensor.
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  • Yoshiki SUGAWARA, Takeshi BABA, Nobuyuki KOBAYASHI
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3648-3656
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    This paper proposes a simple identification system of generalized electromechanical coupling coefficient for passive vibration suppression system by piezoelectric element. The proposed system consists of piezoelectric element, external impedance, voltage source and bridge circuit. Voltage input causes the resonant oscillations of the system and the system yields some resonant frequencies which can be observed from the voltage output of bridge circuit. Applying a formula to the obtained frequencies, the generalized electromechanical coupling coefficient is identified. In the proposed method the method of excitation and measuring of the resonant oscillations are realized by electric and electronic components while the excitation of the conventional method is done by mechanical method. Consequently, the proposed system can be realized in compact and simple configuration and the identification can be realized in simple procedure. Passive vibration suppression system is designed by the use of the parameter which is identified by the proposed method. And experiment of the vibration suppression validates the proposed method.
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  • Akio YANO
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3657-3664
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Piezoelectric actuators using piezoelectric element displacement magnifying mechanism are applied to many kinds of mechanical devices. However, the design of displacement magnifying mechanism depends on experiences and skills of designers and takes much time for optimizing the structure. In this paper the method of structural optimization for displacement magnifying mechanism using FEM and sequential linear programming is proposed. First, the sensitivities of the typical functions, that is, the displacement of nodes, the force of output node, the stress of each elements and the static energy transfer efficiency are formulated. The dictionary of sequential linear programming is constructed out of these sensitivities. Then the optimization procedure which starts from a roughly designed fundamental structure of magnifying mechanism is constructed. Finally the method is applied to an example of punching device to confirm the robustness of the method and the propriety of the optimized structure from the mechanical engineering point of view.
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  • Feifei ZHAO, Shujiro DOHTA, Tetsuya AKAGI
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3665-3671
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Today, the advanced age and less children society is growing up rapidly. The care and welfare equipments to support a nursing care and a self reliance of the senior and the disabled are actively researched. In a wearable system, there are power assisted devices using wearable actuators. However, the power assisted device requires many degrees of freedom. The total weight of the wearable devices increases because the number of actuator and control valves increases according to degrees of freedom. Therefore, in this paper, we propose and test a quasi-servo valve by using the small, light-weight and low-cost on/off control valves driven by the pulse width modulation method. The valve consists of two on/off valves and a microcomputer. We also propose the analytical models of the small-sized on/off valve and the tested valve. The system parameters of the valve are identified. By comparing the experimental results and the calculated results using the proposed model and the identified parameters, we confirm that the analytical model of the valve is valid. Finally, we construct the master-slave control system of the bending angle using the tested quasiservo valve and the flexible bending actuator. And it is confirmed that the tested valve is useful.
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  • Kensaku NOMURA, Toshiro NORITSUGU
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3672-3679
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    In this study, fundamental properties of a hybrid rubber-electromagnetic actuator (RE actuator) are presented. RE actuator including the permanent magnet is introduced. By using the permanent magnet, the heat generation can be reduced because there is no necessity of the bias current. Pushpull operation can be realized by changing the polarity of the electromagnet. And both ends driven type RE actuator, which has driven parts at both ends of the actuator, is newly proposed. As an application of these actuators, a precision stage has been developed. Effectiveness of the stage to the micro manipulation system operated for the microscope has been confirmed.
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  • Hiroaki UCHIDA
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3680-3688
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    It is desirable to establish a posture control method considering the dynamics of the actuator. In the present study, as a model considering the dynamics of the actuator, we constructed a mathematical model in which inputs were the driving torque of the thigh links in the supporting legs and the outputs were the height of the body, the pitching angle, and the rolling angle. The optimal servo control system was designed for this model. As a result of 3D simulation, the proposed control method showed a good following performance to the periodical references of the pitching and rolling angle compared with the control method not considering actuator dynamics. And, in the case of following the periodical references of the body posture, experimental results were almost coincident with 3D simulation results.
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  • Akihiro YAMAGUCHI, Kenjiro TAKEMURA, Shinichi YOKOTA, Kazuya EDAMURA
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3689-3695
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Electro-conjugate fluid (ECF) is a kind of functional fluid, which produces a jet flow (ECF jet) when subjected to high DC voltage. It is known that a strong ECF jet is generated under nonuniform electric field, for example, the field with a pair of needle and ring electrode. This study introduces the ECF jet to develop a novel robot finger. First, we propose a concept of the robot finger which mainly consists of an ECF jet generator, a bending actuator and an ECF tank. The robot finger is driven by ECF jet, and integrated with a pump and a tank. Next, we characterize the ECF jet generator and confirm the effect of the variation of electrode gap and number of electrode pair on its performance. Finally, we investigate the characteristics of the robot finger. The length, the diameter, and the mass of the robot finger are 25mm, 5mm, and 3.8g, respectively. The robot finger can move 27.8mm in x direction and 26.7mm in y direction at 3.1s when ECF jet generator is applied at 6.0kV.
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  • Takashi YAMADA, Tomio WATANABE
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3696-3703
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    In this study, we develop a prototype of pneumatic cylinders-driven arm wrestling robot system called AssistRobot worn on the human upper limb. AssistRobot with 2 pneumatic cylinders and a force sensor can control the force sense to operator's shoulder and elbow. Next, we measure simultaneously human upper limb motion and physiological index of skin surface electromyograms with circulation dynamics in response to forced actions by using the links mechanism of the system. The effectiveness of the system for the analysis of human upper limb motion characteristics is demonstrated. Further, we introduce a force display response model based on the impact absorption of human hand, proposed earlier by the authors, into the system. The effectiveness of the system for arm wrestling is demonstrated by sensory evaluation from viewpoints of user-friendliness and enjoyment.
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  • Shunichi AOYAGI, Yuichi CHIDA, Tetsuji YATSUNAMI, Teruyuki NISHIMURA, ...
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3704-3713
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    A hip protector system using an airbag for prevention of a femoral neck fracture is under developing. In the system, the instance detection of falling motions by using an appropriate on-line algorithm based on sensor signals is required. The purpose of this paper is to propose on-line distinction procedures of human falling motions based on the machine learning, such as the support vector machine and the neural network. Four distinction procedures of falling motions are proposed in the paper, and the procedures use one axis gyro sensor and two axis accelerometers. Three-types of falling motions which cause a femoral neck fracture for elderly people are considered in the paper. The detection performance of the four procedures are evaluated for the three-types of falling motions, and the procedure based on the neural network considering time series of sensor signals provides 100% detection rate for the three-types of falling motions.
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  • Seonghee JEONG, Yoshihiro NAKABO, Takuya OGURE, Yoji YAMADA
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3714-3721
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    This paper proposes a direct teaching device for a multi-D.O.F industrial manipulator considering a worker's safety and operability. The proposed device named as APDT, Attachable and Pose-changable Direct Teaching device, in composed of a pose adjusting part and a teaching handle part. It is capable of easy mounting/unmouting on a robot end-effector and of adjusting a pose of a teaching handle freely without consideration of the pose of an end-effector. By using APDT, a worker is able to perform a direct teaching task for a multi-D.O.F manipulator in a comforable posture even in case of teaching in the large pose change of the end-effector by adjusting the pose of the teaching handle. This will bring the reduction of load of a worker in a long time teaching task. Consequently, the reduction of risk due to inappropriate work posture and the improvement of task efficiency is expected. Simple direct teaching task using APDT with SP02, cell-production robot, was conducted to confirm the effectiveness of APDT.
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  • Chihiro MATSUNUMA, Hiroshi MASUDA
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3722-3727
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    The state-of-the-art mid/long-range laser scanners can capture dense point-clouds from engineering facilities. However, it is very tedious work to manually segment large-scale point-clouds and fit surfaces to the subsets of point-clouds for constructing 3D models. In this paper, we propose a new method to automatically extract cylindrical faces and rectangle faces, which are commonly used for standard parts in engineering facilities. Since it requires a lot of time and memory to search surfaces in large-scale point-clouds, we generate distance images and intensity images from dense point-clouds and estimate canditates of cylindrical and rectangle regions using image processing techniques. Then, we calculate equations of surfaces by applying the region-growing method to the candidate regions, and detect rectangle and cylindrical faces
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  • Koichiro NANBU, Kenichi ITO, Noboru EGAMI
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3728-3735
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Surface modification by fine particle bombardment is mainly influenced by the velocity and diameter of a particle as well as the material properties. In this study, numerical calculation of particles velocity through a convergent nozzle is conducted by considering air as a compressible fluid. Because the axial flow of the convergent nozzle was much more dominant than that of a flat nozzle, the modeling of particle bombardment was accomplished based on a one dimensional isentropic fluid flow. The apparatus presupposed here is a direct pressure-type shot peening machine in which the air inside the nozzle expands and accelerates to the critical speed. Then, the particle accelerates by drag received from air, and the particle velocity increases up to the air velocity. The results of our numerical calculations show the particle velocity obtained from our numerical calculations values is close to that of the experimentally measured values. This demonstrates that our simple and easy model is reasonably accurate and can be used to give insight into the mechanism and selection of optimum drive parameters such as size and material properties of the particles used in the shot peening process.
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  • Toshimitsu KANDA, Shoko AKEMINE, Hiromu HASHIMOTO
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3736-3743
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    A winding model for prediction of in-roll stress, considering air leaking effect is presented. Air layer is formed between webs within wound roll due to air entrainment, and then the thickness varies with air leakage of the widthwise edges and radial stress change while winding. It alters the stress with reducing apparent roll stiffness. In this study, the winding model is based on the assumption that the roll is a series of concentric tensioned hoops which are considered as equivalent layer of web and air layer. On estimating the air layer thickness, the air flow between webs is assumed as an incompressible squeeze flow between parallel plates in axial direction of the roll. In addition, it is extended to take into account that the stress at the already-wound part of the roll is sequentially varied from continuous web winding. Experimental validation result states that predicted value corresponds well to the experimental value amongst a wide range of the processing conditions, winding velocity, winding tension and web width. Furthermore, web width range of application on the winding model is investigated by a parametric study.
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  • Tadashi KARAI, Masaru NAKANO, Fumihiko KIMURA
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3744-3751
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    The purpose of this paper is to estimate and assess a future state of domestic copper supply from a viewpoint of sustainability. The authors develop a simulation model of material flow of domestic copper resources and then estimate the demand and the supply toward 2030. A recycle flow with time series is considered as well for the estimation. Automobile, electric appliance and construction industries are considered in this paper under the scope of recycle laws in Japan. The simulation result illustrates that copper stock in market is estimated to be 4.1 million tons and the copper supply produced from scrap metal is 120000tons. Furthermore, the result prospects shortage of copper resources as much as 54000-59000tons against the domestic demand in 2030 even considering improvement of the recycle system. Therefore, the authors conclude that domestic copper resource is not sustainable in Japan and thus emphasize two important countermeasures such as reducing copper usage for the next generation vehicle and further sharing of recycled resources among other industries.
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  • Yoshitaka TANIMIZU, Kana HARADA, Chisato OZAWA, Koji IWAMURA, Nobuhiro ...
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3752-3759
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Supply chain should be continuously designed and redesigned in order to dynamically configure suitable clients and suppliers in multiple supply chains. Previous researches proposed a dynamic configuration method of two-layered supply chains consisting of a set of clients and suppliers. The proposed method provided suitable delivery times and prices of products by the negotiation between clients and suppliers and by the modification of existing production schedules of suppliers. This research proposes a new model of two-layered dynamic supply chains considering transportation constraint. The new model provides a method for the suppliers to estimate delivery times and prices of products based on not only production schedules but also transportation plans that include constraints about shipping times and loading capacities for transportation. A prototype of dynamic supply chain simulation system was developed and some computational experiments were carried out in order to verify the effectiveness of the new model. The experimental results showed that the prototype system obtained a set of suitable shipping times and loading capacities.
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  • Yasushi MORI, Noboru SUGIMOTO
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3760-3767
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Inherently safe design is becoming more and more important in the environment marked by the increasing failure costs such as costs incurred by recalls and accident handling in various industrial fields. International standards define acceptable risks and tolerable risks based on the principle of "ALARP (As Low as Reasonably Practicable)". However, pursuing the inherently safe design affects judgments made based on the ALARP principle and makes risk management more difficult when other viewpoints including CSR (Corporate Social Responsibility), compliance and brand management are involved. This paper presents a framework for preventive safety management as a measure to counter the above difficulties in risk management. This paper also presents a practical usage of the quantification technique for the qualitative risk assessment, proposed in other paper, and an example of application of such practical usage to risk communication between the management side and the engineers side to improve the qualitative risk assessment.
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  • Toshimichi FUKUOKA, Masataka NOMURA, Takahiro KAMIHIRA, Kensuke KITANO
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3768-3775
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Tire coming-off accident of large vehicles has developed into a social problem that threatens the safety of civic life. One of the major causes of the accidents was that the tire tightening operation had usually been conducted by impact wrenches without torque control function. It is strongly recommended since 2003 to use torque wrenches especially designed for wheel bolts of large vehicles. However, it has not yet been achieved to drastically reduce the number of tire-coming off accidents. Most accidents are traced to the fatigue failure of wheel bolts that tighten the tire wheels to the hub. Therefore, it is strongly desired to elucidate the fatigue failure mechanism of wheel bolts. In this paper, stress amplitudes generated in wheel bolts during tire rotation are measured under live load. The test equipment is constructed utilizing an actual trailer. Compression loads exerted on the wheel bolts are varied corresponding to the actual loading capacity of the trailer including the overloading state. The magnitudes of bolt clamping forces are also changed so as to cover from the normal clamping condition to the loosening one where the wheel bolts are tightened with insufficient clamping forces. Experimental results show that insufficient clamping forces, e.g., less than 30% of the normal value, cause high stress amplitudes in wheel bolts.
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  • Kazuteru NAGAMURA, Kiyotaka IKEJO, Shuji KIHARA, Tetsuya SUMIYOSHI
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3776-3784
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    We designed and made two non-involute helical gears to obtain high performance. One has an involute-cycloid composite tooth profile and the other has a modified cycloid tooth profile. Using these non-involute helical gears, we measured the circumferential vibration acceleration of the helical gears, the tooth root stress, and the transmission error on running tests. The experimental results showed that the vibration characteristics of the non-involute helical gears do not differ from those of an involute helical gear. Furthermore, our pitting test results show that the surface durability of the non-involute helical gears is superior to that of the involute helical gear.
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  • Kiyotaka IKEJO, Kazuteru NAGAMURA, Koki TAKEDA
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3785-3793
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    We carried out a pitting test and a scoring test of spur gears lubricated with three biodegradable oils, a mineral hydraulic oil and a turbine oil. Then, we measured the surface temperature on the gear tooth by a dynamic thermocouple, and observed the lubrication condition between meshing teeth by the electrical resistance method to investigate the effect of the biodegradable oil on the tooth surface failure of spur gear. It was found that the pitting resistances of biodegradable oils are higher than that of the mineral hydraulic oil and lower than that of the turbine oil, and that biodegradable oils have higher scoring resistance than the mineral hydraulic oil and the turbine oil.
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  • Norihiro KIMURA, Yosuke TSUKIYAMA, Takayuki TOKOROYAMA, Noritsugu UMEH ...
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3794-3799
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Carbon nitride (CNx) coating is one of the carbonaceous materials, which was reported to show superlow friction coefficient (μ<0.009) in Nitrogen environment. Therefore CNx coating is a promising material of solid lubricant for sliding interfaces to reduce friction. The superlow friction appeared after running in process of several hundreds of friction cycles and its mechanism has not been completely clarified yet. It was proposed that the soft thin layer generated on CNx coating after running-in process contributed to the superlow friction. However, the mechanical properties of the superficial layer of CNx coating such as hardness and Young's modulus have not been experimentally shown because of its small thickness estimated to be 10nm or less. So we carried out in-depth measurements of mechanical properties of the thin layer on CNx film by nanoscratching test using an atomic force microscope. Then the existence of thin, soft layer on the top of CNx coating after running-in process was experimentally shown.
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  • Ryuta NAKAMURA, Akira IWABUCHI, Michimasa UCHIDATE
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3800-3805
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Generally, it is known that graphite decreases friction and wear of cast iron. However, the literatures that logically explained this common sense are few. In this study, we observed the surface before and after friction test in lubricant test and dry test by SEM, EPMA and XPS to clarify the mechanism. In lubrication test and mild wear region of dry test, increase in the carbon content was confirmed on the top surface. However, it has decreased on the top surface in severe wear region of dry test. And, we proposed the wear mechanism that first, graphite in cast iron was extruded in cast iron matrix to the surface by plastic deformation, it was supplied to the top surface, it was rolled and extended on the surface, and ultra thin carbon film of about 2nm was formed on the surface.
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  • Yoshihiro TAKAHASHI, Masahiko UEKUSA, Yoshiaki TERUMICHI
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3806-3813
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Barrel polishing is an extremely efficient processing method for surface smoothing treatment of a large number of workpieces. However, workpieces and grinding materials may separate depending on the processing conditions. Therefore, examination of the processing conditions using dynamic analysis of the behaviors of workpieces and grinding materials is strongly desired. In this study, the behavior of the particles in the planetary barrel that simultaneously rotates around a horizontal axis and revolves around a vertical axis was examined through experiments and simulations using the discrete element method (DEM). The center of the rotary barrel was set up so that the centrifugal force might act on the particles in this barrel. As a result, it was demonstrated that the distribution of two kinds of particles might be replaced by setting position of the center of the rotary barrel even if in same combination of particles.
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  • Takehisa KOIZUMI, Keiichi NAKAMOTO, Tohru ISHIDA, Yoshimi TAKEUCHI
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3814-3821
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    In recent years, the efficient machining of workpieces with a complicated shape has being increased in terms of realizing the products with compact design and sufficient functionality. 5-axis control machining center is suitable to meet such a requirement. However, it is necessary to obtain adequate tool postures to avoid interference between the cutting tool and the workpiece while machining workpieses with complicated sculptured surface. This study deals with rapid tool path generation for 5-axis control machining to treat such complicated product shapes on the basis of a proposed method. For tool path generation, the product shape is divided into small area. Each divided area is subjected to interference check. This new CAM system can generate automatically interference-free NC data in 5-axis control machining. The validity of the developed system is demonstrated with machining simulation and experiment.
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  • Ikuo TANABE, Tetsuro IYAMA, Aung Lwin Moe, Ryuichi KONDO
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3822-3827
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Recently, mirror-like surface is required for adding high quality on the most products. Polishing process is almost used for machining the mirror-like surface. However, when many workers make a large die and mold with the mirror-like surface in many machine shops, it is necessary for them to polish very long time. Therefore, in this paper, high speed polishing for large die or mild was developed and evaluated. The polishing system for large die and mold consists of the NC milling machine and the polishing tool using the several polishing units. And the polishing unit consists of polishing head, spring, shaft and linear guide. The polishing unit with no-chatter was firstly developed, and the optimum polishing condition for the unit was investigated in several experiments. The polishing tool was developed for a large die and mold by using the several polishing units. This system was evaluated for high speed polishing on the flat and curve surfaces of the large die. It is concluded from the results that (1) Mirror-like of large die and mold surface were machined by this polishing system, (2) The polishing time using this polishing system is one over three hundred than that of the conventional polishing.
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  • Satoshi KITAYAMA, Masao ARAKAWA, Koetsu YAMAZAKI
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3828-3836
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    The Differential Evolution (DE), which is the population-based optimization technique, is one of the global optimizers for the continuous design variables such as the Particle Swarm Optimization (PSO). In the traditional DE, due to the mutation in the algorithm, the rounding-off and truncating are often employed to handle the discrete and integer variables. In this paper, the Discrete Differential Evolution (DDE) to handle the discrete or integer design variables is proposed. In the proposed DDE, the mutation is considered as the exchange possibility between two particles. By considering the mutation as the exchange possibility, it is easy and possible to handle the discrete and integer variables. In addition, the initialization of the population are also introduced in the proposed DE. It is possible to escape from local minimum by introducing the initialization of the population. The algorithm of the proposed DDE is very simple, and can be easily extend to the Mixed-Discrete Nonlinear Problems (MDNLPs). The proposed DDE can be applied to a variety of discrete and integer optimization problems. The validity is examined through typical benchmark problems.
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  • Yasuhiro TANI, Ryuzo UDA, Takeo KUSUMOTO, Junji MURATA, Yu ZHANG
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3837-3842
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    Lapping carriers are used as retainers of workpieces in double side polishing. High carbon steel is a material widely used for the lapping carrier due to the high hardness and tensile strength of the material. However, the thin steel carries are expensive because of their complex fabrication processes. In this paper, we propose a novel fabrication process of the lapping carriers using a electroforming technique to reduce costs of carriers. Ni-P alloy electroforming and composite electroforming with potassium-titanate fiber are found to be effective to improve hardness and tensile strength, respectively. The electroforming film having a high hardness and strength equivalent to the high carbon steel can be realized using Ni-P-Fe alloy electroforming. A photo-resist patterning method enables us to fabricate thin and high precision electrode rapidly. It is confirmed that the fabricated carries can be used in the double side polishing machine.
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  • Takeshi NAKAMOTO, Shinya KOJIMA
    Article type: Article
    2010 Volume 76 Issue 772 Pages 3843-3848
    Published: December 25, 2010
    Released on J-STAGE: June 09, 2017
    JOURNAL FREE ACCESS
    The purpose of this research work is to produce micro part reinforced by unidirectional short fibers by laser photolithography. Ferromagnetic short fibers are added to liquid photopolymer. By applying magnetic field to this mixture, the axes of the short fibers are aligned along the direction of the magnetic field. Then, the photopolymer is solidified by the irradiation of UV laser in the desired shape. The solidified thin films with aligned short fibers are layered until the desired height is obtained. The surfaces of the solidified thin layers are observed by scanning electron microscope and the possibilities of the reinforcing effect between each layer are examined. Several examples of micro structure reinforced by unidirectional short fibers are produced by this method.
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