JSME International Journal Series C Mechanical Systems, Machine Elements and Manufacturing
Online ISSN : 1347-538X
Print ISSN : 1344-7653
ISSN-L : 1344-7653
Volume 49, Issue 3
Special Issue on Advanced Technology of Vibration and Sound
Displaying 1-42 of 42 articles from this issue
PAPERS
  • (27kHz to 180kHz Ultrasonic Plastic Welding Systems)
    Jiromaru TSUJINO, Misugi HONGOH, Masafumi YOSHIKUNI, Hiroyuki MIURA, T ...
    2006 Volume 49 Issue 3 Pages 634-641
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    Welding characteristics and temperature rises at plastic welding part over frequency range from 27kHz to 180kHz were studied. Ultrasonic plastic welding systems of 27, 40, 67, 94, 150 and 180kHz were developed and direct welding characteristic of lapped plastic sheets were measured. The temperature rises at welding surfaces of lapped 1.0-mm-thick polypropylene and polymethyl methacrylate plates were measured using thermocouples inserted between plate specimens. And also, temperature rise distributions in cross sections of the lapped plate specimens were measured using a thermotracer. The longitudinal vibration systems used for ultrasonic plastic welding consisted of a bolt-clamped Langevin type longitudinal vibration source using two or four piezoelectric ceramic (PZT) rings, a stepped horn and a catenoidal horn with a 4-mm- or 8-mm-diameter welding tip. Using higher frequency system, temperature rise measured at the welding part were higher. Maximum temperature rise measured using thermocouples and a thermotracer was over 350°C under excessive condition.
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  • Yasutomo KANEKO, Kazushi MORI, Masayuki TOMII
    2006 Volume 49 Issue 3 Pages 642-647
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    The objective of this study is to verify the reduction effect of the friction damper on the vibratory stress of the compressor vane both theoretically and experimentally. First, an analysis method for predicting the damping characteristics of the compressor vane with a friction damper, which applies the substructure synthesis method and the harmonic balance method, is proposed. Secondly, an excitation test of the damper vane is carried out to verify the validity of the analysis method proposed here, and to confirm the damping characteristics of the damper vane. In the excitation test, a newly developed magnetic exciter, which applies the feature of the resonant circuit, is used to vibrate the vane with large excitation force. Vibration characteristics of the damper vane predicted by the analysis show good agreement with the measured results. Finally, to verify the effect of the friction damper, the field test of the actual gas turbine is carried out, where the vibratory stress of the compressor vane with and without the friction damper is measured.
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  • János VAD, Gábor KOSCSÓ, Miklós GUTERMUTH, ...
    2006 Volume 49 Issue 3 Pages 648-656
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    Comparative acoustic and wind tunnel experiments were carried out on uncoated and coated isolated airfoils. The aim of the tests was to survey the airfoil noise reducing effect and the aerodynamic impact of the acoustically soft coating consisting of filaments, as a preliminary study in application of such coatings to axial flow turbomachinery bladings. It was found in the acoustic tests that the coating successfully reduces the sound pressure in the frequency range critical from the aspect of human audition. The wind tunnel experiments included laser Doppler anemometer studies on the development of the boundary layers and on the wake structure, and static pressure measurements on the blade surface and in the wake. The coating reduced the lift and increased the drag. A proposal has been made for further studies in order to retain the advantageous acoustic effects of the coating while avoiding the undesirable aerodynamic impact.
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  • Cheng-Ho LI, Pei-Lum TSO
    2006 Volume 49 Issue 3 Pages 657-662
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    In this paper, we proposed a concept of using both a linkage balancer and counterweight disks to reduce shaking force and shaking moment of high-speed mechanical presses. The linkage balancer is designed with analytic synthesis method for matching critical shaking forces at the right timing. Counterweight disks’ positions and masses are designed with an optimum method that considers minimizing the magnitude and the fluctuation of the shaking effect. A practical design example on a Stephenson III six-bar linkage press is presented for illustration. The conclusion showed that the shaking force/moment could be effectively reduced. Comparatively, the linkage balancer and the counterweight disks are apt at dealing with shaking force and shaking moment, respectively.
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  • Naoki KANAMORI, Masaharu NISHIMURA, Takumi MISHIRO
    2006 Volume 49 Issue 3 Pages 663-669
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    This paper describes designs of structures and control systems of an active sound insulation unit consisting of active cells which are individually controlled as a single input single output system. Two types of Active Sound Insulation Cell (ASIC) using lightweight card-type speakers were manufactured for trial. It became clear that ASIC can reduce the transmitted noise whose sound field inside the cell is uniform. That means that the size of ASIC should be less than quarter wavelength of controlled sound and secondary noise sources should be properly arranged. The feedback control system for ANC was systematically designed by H-infinity control theory, and the sound attenuating performance was verified by the simulation.
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  • Masao NAGAMATSU
    2006 Volume 49 Issue 3 Pages 670-674
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    Among sound source localization methods, the acoustic intensity (AI) method is widely used in industry. On the other hand, nearfield acoustic holography (NAH) method, which is also a localization method, has not spread to industry use because of its difficulty in measuring high frequency measurement. For high frequencies, the NAH method requires a very large number of measurement points, which results in a prolonged measurement time and very large size. I have proposed a theoretically converted NAH method(1),(2), which uses the extra spatial-domain spectrums in the backpropagating computation of NAH method. This method can measure the sound field using a reasonable number of measurement points even for high frequencies. As a result, the workload of measurement is reduced to the same level as that using acoustic intensity method. In this paper, the theory of the proposed method is explained, and some experimental results are presented to verify this method.
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  • Subaru KUDO
    2006 Volume 49 Issue 3 Pages 675-680
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    Tactile sensors have been used for sensing the softness and the hardness of an object. They make use of changes in the resonance frequency and the Q-value of resonators, which are induced when their vibrating sections are brought into contact with an object. This study proposes a new vibratory tactile sensor integrated a longitudinal bar type resonator and a force sensor. The resonance frequencies and these vibration modes of the tactile sensor are calculated using the finite element method. The sensitivity of the force sensor with a double-ended tuning fork resonator is analyzed and designed. The sensitivity of this force sensor is clarified experimentally. Then, the characteristics of the tactile sensor are confirmed using test pieces with different hardnesses. This longitudinal bar resonator integrated with a double-ended tuning fork resonator as a force sensor has potential as a high performance tactile sensor.
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  • Hiroyuki MASUYAMA, Koichi MIZUTANI
    2006 Volume 49 Issue 3 Pages 681-686
    Published: 2006
    Released on J-STAGE: March 15, 2007
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    A method for scanning a radiated acoustic beam is described, by introducing a concise decentering operation in an annular transducer array sound source. For generating a narrow acoustic beam, we have proposed the simple method of using a concentric annular array in which the width of each element is weighed by the J0 function. Additionally, by applying a clearance that exists between each neighboring element of the array to decenter the array elements, we have shown that the direction of the radiated acoustic beam is made to be variable. Even when this decentering procedure is optimally, the shifting of the propagation path of the beam still occurs, and it is possible to scan the beam precisely. Using numerical calculations, we show the scanned aspect of the narrow beam generated by this method. The validity and applicability of this method are then examined.
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  • Taichi SATO, Keiichi OYAMA, Miki IIMURA, Harumi KOBAYASHI, Kihachiro T ...
    2006 Volume 49 Issue 3 Pages 687-694
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    We have performed basic experiments for the purpose of applying onomatopoeia to engineering problems. In these experiments, test subjects were made to perform lifting actions while listening to onomatopoeic utterances. We thereby demonstrated that there is a relationship between the onomatopoeic utterances and the lifting forces exerted by the test subjects. We examined how the lifting forces are related to the envelope of onomatopoeic utterances. Furthermore, we investigated how the lifting force is affected depending on whether or not emotion is expressed when uttering the onomatopoeia.
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  • Jiromaru TSUJINO, Tetsugi UEOKA, Yuya KIKUCHI
    2006 Volume 49 Issue 3 Pages 695-702
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    The ultrasonic complex vibration systems with elliptical to circular locus are effective and essential for new high power applications in various industries. Configuration of a 27kHz and a 40kHz complex vibration source with a complex transverse vibration rod with a welding tip part and a longitudinal and transverse vibration disk with six and four bolt-clamped Langevin type PZT longitudinal transducers and welding characteristics of aluminum and aluminum alloy plates using complex vibration systems were studied. Outer diameters of the 40kHz complex vibration sources are 191 to 195mm which are about half of the diameter 395mm of the 27kHz vibration source. Stepped complex transverse-vibration rods with a welding tip is installed in the center of the disk and is driven in circular vibration locus at the free edge of the rod (welding tip) using three and two 500W power amplifier systems.
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  • Hiroshi KOBAYASHI, Masaharu KOH, Shunichi OZAKI, Makoto YOKOCHI, Takuo ...
    2006 Volume 49 Issue 3 Pages 703-712
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    The paper describes about a newly-developed adaptive noise absorption control (AAC) technology I for fan noise reduction and about proof test results of the technology. The AAC technology adaptively controls the reactance part of acoustic impedance of duct liners with mobile reflective plates and large acoustic chambers, absorbs fan tones and broadband noise together, and achieves larger overall fan noise reduction over a wide fan speed range. For actual proof of the technology, adaptive duct liner I was made on trial basis and was examined. The test result clarifies that the duct liner I could reduce fan noise larger than O.A. SPL 10dB (A) at max fan speed of 6000rpm, including reduction of low frequency noise and fundamental BPF tone and harmonics of 18dB at maximum. In response to fan speed change, the reflective plate movement control could achieve the large peak frequency shift and peak level increase in the acoustic absorption spectra, and could reduce fan noise larger than O.A. SPL 9dB (A) over the fan speed range from 1000 to 6000rpm.
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  • Noritoshi NAKAGAWA, Masaya FUJIHARA, Chaoqun WU, Jun SATONOBU
    2006 Volume 49 Issue 3 Pages 713-718
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    Since fouling generated inside pipes of chemistry plant equipment, shortens “its life”, periodical maintenance such as cleaning or replacement is needed. Therefore, the development of a safe and sanitary method of preventing a corrosion and blockage inside pipes is desired. In this study, a vibration system, composed of a bolt-clamped Langevin transducer and a pipe, was employed to experimentally study the possibility of fouling removal. In the experiment, a flexural vibration was excited in a pipe containing fouling using ultrasonic waves. When the pipe was made to vibrate, with calcium carbonate or starch used as the fouling, it was shown that the fouling was diffused into the air, and except at the node of the flexural vibration, the fouling was removed completely. Also, the result showed that a higher input voltage to the transducer was more effective in removing the fouling.
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  • Md. Emdadul HOQUE, Masaya TAKASAKI, Yuji ISHINO, Hirohisa SUZUKI, Take ...
    2006 Volume 49 Issue 3 Pages 719-726
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    In this paper, a three-degree-of-freedom vibration isolation system using active zero-power controlled magnetic suspension is presented in order to isolate vibrations transmitted from the ground and to attenuate the effect of direct disturbances on the table. The zero-compliance of the isolator for direct disturbances was realized by connecting a conventional mechanical spring in series with a negative spring produced by an active magnetic suspension mechanism. In this work, each degree-of-freedom-of-motion of the vibration isolator is treated analytically and it is shown that the developed system is capable to generate infinite stiffness in each mode. Experimental studies have been conducted as well to measure the effectiveness of the isolator under both types of disturbances. Further improvements for the developed system as well as the control techniques are also discussed.
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  • Gan-wei CAI, Ru-gui WANG, Zhao-jun LI
    2006 Volume 49 Issue 3 Pages 727-733
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    The work in this paper is concerned with a four-bar linkage mechanism with links fabricated from three-dimensional braided composite materials. The dynamic equation of the mechanism is established by finite element method (FEM), it includes composite materials parameters and structural parameters of the mechanism. The mass matrix of the beam element is obtained in light of the mass distribution characteristics of the composite materials. According to the 3-dimensional microstructure characters of the three-dimensional braided composite materials, the anisotropic beam element is considered to be made up of four parts, and then the stiffness matrix of the beam element is derived from the constitutive equations of each part and the relation between the strain distribution of each part and the node displacement of the beam element. Based on the damping element model and the expression of dissipation energy of the 3-dimentional braided composite materials, each modal damping value of the mechanism is calculated and the damping matrix of the mechanism is established. The dynamic responses and natural frequency of the mechanism are obtained by simulation, respectively. The work presented in the paper provides theoretical basis to a certain extent for the further research on nonlinear vibration characteristics and optimum design of this kind of mechanism.
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  • Bo-Suk YANG, Tian HAN, Zhong-Jun YIN
    2006 Volume 49 Issue 3 Pages 734-741
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    This paper proposes a fault diagnosis system for induction motor which integrates principal component analysis (PCA), genetic algorithm (GA) and artificial neural network (ANN). Vibration signals and stator current signals are measured as the fault diagnosis media. Many sensors result in many features to ANN. In order to avoid the curse of dimensionality phenomenon and improve the classification rate, PCA and GA are employed to reduce the feature dimensionality of the measured data. PCA removes the relative features. Then the irrelative features after PCA are selected by GA to find better feature subset as inputs to the network under a few population and generations. GA is also used to optimize the ANN structure in that the selected PCs feature subset is evaluated by it. The efficiency of the proposed system is validated by comparison of other three systems: ANN only, ANN with PCA and ANN with GA. The classification success rate for the ANN with PCA and GA was 100% for validation, while the rates of ANN only, ANN with PCA and ANN with GA were 83.33%, 86.67% and 98.89%, respectively.
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  • Junichi HINO, Seiichi OKUBO, Toshio YOSHIMURA
    2006 Volume 49 Issue 3 Pages 742-749
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    This paper is concerned with a study of chatter prediction in high-speed end milling operations. Chatter vibration occurring in mechanical machining gives rise to poor surface finish and dimensional inaccuracy in machined parts, reduction of tool life, and even damages machine tools. Various studies of its prediction and avoidance have been carried out over the last several decades. The purpose of this study is to develop an expert system for predicting chatter vibrations in high-speed end milling using wavelet transform and fuzzy neural network models with pruning. The FNN model employed here uses a pruning process which reduces a neural network to its most effective size. The amount of learning for convergence of a pruned network is reduced in comparison with an initial network. The proposed method is applied to a jig grinding machine, and the results demonstrate the effectiveness of the chatter prediction procedure.
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  • Kazunari NAKAHARA, Noritoshi NAKAGAWA, Katsutoshi OHTA, Tetsuya MIYAKE ...
    2006 Volume 49 Issue 3 Pages 750-757
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    The dynamic characteristics of exhaust hangers for automotive use are studied for high frequencies at which the resonance vibration of the exhaust hangers occurs. A newly developed exhaust hanger composed of rubber and a thin metal ring is presented, which can provide a lower dynamic stiffness in a wide frequency range than an exhaust hanger made of solid rubber. A dynamic characterization testing and finite-element analysis of the exhaust hangers were carried out to clarify the frequency responses of dynamic stiffness in the high-frequency range. A method of treating the viscoelasticity of the rubber material using the finite-element method is proposed to predict the dynamic characteristics of the exhaust hangers. The finite-element method results show a good agreement with the experimental results for the frequency response of dynamic stiffness. Concerning the newly developed exhaust hanger, the effects of metal ring geometry and rubber hardness on the dynamic stiffness are examined to demonstrate the design principle for providing a low dynamic stiffness in a wide frequency range.
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  • Chaoqun WU, Noritoshi NAKAGAWA, Masaya FUJIHARA
    2006 Volume 49 Issue 3 Pages 758-763
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    Applications of ultrasound in cleaning industry and biomedical field are owed to acoustic cavitations. To investigate behaviors of acoustic cavitations, a standing wave field of piston ultrasonic radiation was set up in this paper. And the behaviors of acoustic bubbles in this standing wave field were studied experimentally. Expressions of sound pressure in this standing wave field with different boundary conditions were discussed. Drawn by the forces (Bejerknes forces, Buoyancy forces, etc.), stable bubbles distributed regularly in the standing wave field. Experiments were conducted to validate that the distribution of stable bubbles can visualize the distribution of sound pressure. Erosion tests on aluminum foiling demonstrate that erosion only occurs in sound pressure anti-node field which was caused by collapsed acoustic bubbles. The radial oscillation of acoustic bubble was observed using high speed camera; it was found that the bubble’s radius was increased with increase of negative sound pressure.
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  • Meifal RUSLI, Masaaki OKUMA, Takeshi NAKAHARA
    2006 Volume 49 Issue 3 Pages 764-770
    Published: 2006
    Released on J-STAGE: March 15, 2007
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    Modal curve fitting methods on frequency domain are based on the least square method to estimate the modal parameters from frequency response functions (FRFs in brief) of test structures. In order to minimize the least square errors between experimental and estimated FRFs, several kinds of weighting functions were proposed and widely applied in practical use. However, using the same weighting function in modal curve fitting for a set FRFs of test structure often makes the results of the FRFs of some measurement points be fitted with good accuracy but other ones be not. In this paper, the authors propose the combination use of various kinds of weighting functions in least square process of modal curve fitting methods to deal with the measurement data of actual and complex mechanical systems. This method automatically selects and applies the most appropriate weighting function to the FRF of each measurement point by comparing the minimum total relative mean square error (RMSE). The case study shows that the proposed idea allows the modal curve fitting method puts better curve fitting results out so that more accurate mathematical model will be obtained.
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  • Fumiyasu KURATANI, Tetsuo SHIMADA, Tadao YAMANO, Takeshi OGAWA
    2006 Volume 49 Issue 3 Pages 771-778
    Published: 2006
    Released on J-STAGE: March 15, 2007
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    In this paper, we propose a procedure for predicting the modal data of a thin plate structure with a rib stiffener even when the rib is attached at a location where mode shapes are not measured. This procedure is based on the structural dynamics modification (SDM) method in which the mode shape expansion (MSE) method is incorporated to estimate the experimental mode shapes at the unmeasured points. In the MSE estimation, a submodel including the possible rib attachment points is used instead of the whole structure model. Numerical examples through the plate structure with the two L-shaped ribs show that the proposed procedure accurately predicts the modal data using the estimated mode shapes at the unmeasured points. The mode shapes are estimated satisfactorily with the submodel under a free boundary condition. The optimal number of analytical modes to be combined in the MSE estimation can be determined from the condition number of the modal matrix of the submodel.
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  • Kwon-Hee LEE, Gyung-Jin PARK
    2006 Volume 49 Issue 3 Pages 779-788
    Published: 2006
    Released on J-STAGE: March 15, 2007
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    The current trend of design methodologies is to make engineers objectify or automate the decision-making process. Numerical optimization is an example of such technologies but it may produce uncontrollable uncertainties. To increase manageability of such uncertainties, the Taguchi method, reliability-based optimization and robust optimization are commonly being used. The main functional requirement of a mechanical system is to obtain the target performance with maximum robustness. In this research, a design procedure for global robust optimization is developed using kriging and global optimization approaches. Robustness is determined by kriging model to reduce a number of real functional calculations. The simulated annealing algorithm of global optimization methods is adopted to determine the global robust optimum of a surrogate model. As the postprocess, the global optimum is further refined by applying the first-order second-moment approximation method. Mathematical problems and the MEMS design problem are investigated to show the validity of the proposed method.
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  • Daigoro ISOBE, Atsushi YAGI, Shunsuke SATO
    2006 Volume 49 Issue 3 Pages 789-798
    Published: 2006
    Released on J-STAGE: March 15, 2007
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    In this paper, an algorithm for the general-purpose expression of structural connectivity is developed and implemented into the parallel solution scheme, which was previously proposed and successively applied to the feed-forward control of link mechanisms under various boundary conditions. The parallel solution scheme calculates the inverse dynamics of link systems by using a matrix-form equation separated into individual terms of different parameters. Therefore, the connectivity of link members can be expressed explicitly by one of the matrices, the member length matrix. Generated forces for the control can also be considered, without using any Jacobian matrices, simply by adding the values into one of the components in the equation, the vector related to nodal forces. We describe the forming process of the member length matrix and verify the validity of the calculated torque values, by presenting simple numerical results and experimental results for a structure-varying link system. We also perform a force control experiment on a quick motion, two-arm link system holding an object, where both generated forces and dynamical effects should be considered. Numerical and experimental results show the validity and the extensive ability of the scheme.
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  • Yusaku FUJII, Takao YAMAGUCHI
    2006 Volume 49 Issue 3 Pages 799-803
    Published: 2006
    Released on J-STAGE: March 15, 2007
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    Dynamic characteristics of a rubber car wiper blade, that are the viscoelasticity under impact load and the dynamical friction, have been accurately evaluated by means of an optical method. In the method, force is generated and measured as the inertial force acing on a mass. A linear air bearing is used to realize a linear motion with sufficiently small friction acting on the mass, i.e. the moving part of the linear bearing. The inertial force acting on the mass is calculated from the velocity of the mass. The velocity is determined highly accurately by means of measuring the Doppler shift of the frequency of the laser light beam reflecting on the mass using an optical interferometer. The viscoelasticity of the wiper blade under impact load is determined by means of colliding the mass with it. The kinetic friction acting between the wiper blade and glass plate is determined by means of pressing the wiper blade onto the glass plate attached on the upper surface of the mass, whose initial momentum is given manually. Using the developed instrumentation, both the viscoelasticity under impact load and the dynamical friction of the wiper blade are easily and accurately determined based on the definition of force.
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  • Joo Hyun BAEK
    2006 Volume 49 Issue 3 Pages 804-813
    Published: 2006
    Released on J-STAGE: March 15, 2007
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    A model of an azimuth driving servo system with a flexible antenna in a tracking system was derived in this work. The validity of the model was verified by comparing the results of the model with experimental results. When modeling the dynamics of a gimbal with an antenna, the antenna should be considered as a flexible body. The effect of reducing the magnitude of the backlash that results in extending the bandwidth in a system with a flexible antenna is smaller than the effect of reducing the magnitude of the backlash in a system with a stiff antenna. When there is a need to reduce the weight and extend the bandwidth, the derived model enables the design of a tracking system to be optimized.
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  • Takeshi KAWASHIMA
    2006 Volume 49 Issue 3 Pages 814-820
    Published: 2006
    Released on J-STAGE: March 15, 2007
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    The purpose of this study is to realize a comfortable swing according to the condition of each individual person. A simple active rocking chair is developed, the swing of which changes with the heartbeat fluctuation of the seated person. The active rocking chair is driven by a solenoid for safety and silence. Swinging is strengthened when the period of the heartbeat lengthens, and it is weakened when the period shortens. Swinging is evaluated using a questionnaire of 16 bipolar scales that was developed for the evaluation of comfortable swinging on the basis of the semantic differential (SD) technique. As a result, it is confirmed that comfortable swinging is realized by the developed active rocking chair. Then the acceleration near the ear of the seated person is measured in order to examine the features of comfortable swinging using the feedback of heartbeat fluctuation. It is clarified that the power spectrum of the envelope of the acceleration waveform shows “1/f fluctuation”.
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  • Yusuke KOBAYASHI, Hiroaki SEKI, Yoshitsugu KAMIYA, Masatoshi HIKIZU, M ...
    2006 Volume 49 Issue 3 Pages 821-827
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    Wheelchair users need lifts to climb up/down steps at entrances with limited space. Lifts driven by motors or hydraulic equipment are large and expensive. They also need switches to start/stop actuators. The aim of our study is to develop a compact nonpowered lift for wheelchair users. We propose a lift driven by the wheels of a wheelchair on it. Coil springs are installed in the lift to decrease driving torque and some mechanisms are attached to the lift so that the small front casters of a wheelchair can cross the lift stage and the large rear wheels can drive the lift. After the lifting speed, driving force, and conditions for driving the rollers were analyzed and a prototype lift was designed and fabricated. The developed lift succeeded in raising a wheelchair with a user, and a continuous motion of a wheelchair from entering to exiting the stage was executed smoothly.
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  • Toshihiro MATSUI, Chihiro NAKAJIMA, Yuichi YAMAMOTO, Masayoshi ANDOH, ...
    2006 Volume 49 Issue 3 Pages 828-836
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    The motion of the inner hair cell (IHC) stereocilia, which results in tension in the tip links connected to mechanically gated ion channels, mediates the auditory transduction process. However, it is difficult to directly observe the motion of the stereocilia because of their minute dimensions and complex structure. In this study, to investigate such motion, a finite element method model of the tall, middle and short IHC stereocilia, including the tip and lateral links extending between the stereocilia, was constructed. By applying an analytically estimated fluid force caused by a stimulus of 60dB SPL at 500Hz to the model, the dynamic behavior of the stereocilia was analyzed. Numerical results showed that the stereocilia moved in phase and that the maximum tensions of 2.5fN and 2.1fN occurred in the tip link connecting the tall and middle stereocilia and in the tip link connecting the middle and short stereocilia, respectively. By contrast, under the condition in which the lateral links were removed, maximum tension in the former increased to 11.6fN, while that in the latter only increased to 2.3fN. It was therefore suggested that the lateral links protect the MET channels located at taller stereocilia against large stimuli and subject the channels located in the same IHC to forces of similar size.
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  • (Effects of Design Variations of the Washout Hole, the Pivot and the Back Gap)
    Masahiro NISHIDA, Takashi YAMANE, Osamu MARUYAMA, Yoshiyuki SANKAI, Ta ...
    2006 Volume 49 Issue 3 Pages 837-851
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    Flow mechanisms within a monopivot centrifugal pump were clarified in order to prevent stagnation around the pivot bearing, which may cause thrombogenesis. We focused on the geometric effects of the pump, which included the effects of the washout hole diameter, the pivot friction area and the back gap width of the impeller relative to the washout around the pivot bearing. Flow patterns were carefully examined around the pivot bearing, including the region inside the washout hole and the back gap of the impeller, by computational fluid dynamic analysis. Based on the results from the computational fluid dynamic analyses, we found that a balance relationship between the washout hole diameter and the back gap width of the impeller affected the secondary flow toward the pivot bearing that eliminated the stagnation around the pivot bearing. In addition, while increasing in the pivot friction area eliminated stagnation around the pivot bearing, it also increased hemolysis within the pump.
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  • (Differentiation of Bone Marrow Stromal Cells and Myoblasts)
    Tomoyuki UCHIDA, Fumihito ARAI, Osamu SUZUKI, Akihiko ICHIKAWA, Toshio ...
    2006 Volume 49 Issue 3 Pages 852-858
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    A novel biochip is developed for culturing stem cells. Biochip is made of Polymer (PDMS), and cells can be loaded by gradient strains in one chip. They grow well on a hydrophilic membrane and differentiation is promoted by cyclic strains. In this paper, we propose the method for culturing and monitoring of stem cells such as bone marrow stromal cells (ST2 cells) and myoblasts (C2C12 cells), and the results of culture. First we analyzed strains on a membrane when an air hole is decompressed, and clarified their range. From experiment, bone marrow stromal cells grew well in a narrow range, and we quantified their ALP activity as a measure of differentiation. As myoblasts, the direction of their differentiation was perpendicular to a groove, that is, the same direction of uniaxial strains.
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  • Suthasinee KASEMSARN, Banchong MAHAISAVARIYA, Kriskrai SITTHISERIPRATI ...
    2006 Volume 49 Issue 3 Pages 859-864
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    The dimension and number of implants as well as the splinting concept of the superstructure are the impact factors of the immediate loading implant-supported prostheses. The purpose of this study is to determine the morphometric data of Thai lower edentulous jaws between two metal foramens for optimizing the design. Sixty-four Thai cadaveric edentulous mandibles were CT scanned and 3D models were reconstructed. Arch forms, dimensions, and the area of the greatest concavity in the body of the mandibles between the metal foramens were defined in geometric terms based on reverse engineering methods. The arch forms, represented by average values of angle and distance of panoramic arc, were 116.4 ±9.5 degrees and 46.7 ±3.9mm respectively. The dimensions of the mandibles, determined by the height and width of the body of the mandibles as well as the angle between the axis of the mandibular body to the mandibular plane, were 25.3 ±0.6mm, 11.6 ±0.6mm and 61.3 ±1.7 degrees respectively. The area of greatest concavity was 8.3 ±1.9mm. Morphology of the Thai edentulous mandible determines the maximum length of an implant placed for immediate loading protocol as 17mm, with a maximum diameter of 3.5-5mm. The maximum number of implants that can be placed in the anterior region is 5.
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  • Tomonao OKUYAMA, Hiroshi MATSUHISA, Hideo UTSUNO, Jeong Gyu PARK
    2006 Volume 49 Issue 3 Pages 865-872
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    In active noise control (ANC), the transfer function of the error path (TFEP) changes when the evaluation point moves, and it causes a bad performance of noise control. In this study, a new method to identify TFEP at an arbitrary point is proposed. This method is based on the plane wave theory, and the impulse response of TFEP is derived analytically as a function of the position, using measured impulse responses at two points. Applying this method to update the compensation filter of the varying TFEP in a test tube, it is verified by the experiment that the noise can be suppressed significantly without divergence.
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  • Byoung Sam KIM, Bong Goo RHEE, Tae Keun LEE
    2006 Volume 49 Issue 3 Pages 873-881
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    Vibration characteristics of a tire play an important role to judge a ride comfort ability and sound quality for a vehicle. In this study, the experimental investigation on the sound radiation of a radial tire has been examined. Based on the sound intensity techniques, the sound pressure field and the sound radiation are measured. It turns out that air pressure in tire, tread patterns, and aspect ratio of the tire governs the sound radiation characteristics. Then a numerical analysis for the tire element is conducted. During analysis, the tire element is modeled as an elastic ring. The comparison shows that the numerical output correlates to the experimental data.
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  • Jian-Feng TSAI, Yon-Ping CHEN
    2006 Volume 49 Issue 3 Pages 882-889
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    Switched reluctance motors (SRM) possess several superiorities such as simplicity in structure, ruggedness, and good reliability, which make it viable for the transportation applications. In this paper, an axial-flux disk-type switched reluctance motor (DSRM) for hybrid scooters is proposed. The DSRM can be used to drive the scooter and as an engine starter simultaneously. Moreover, the torque density of axial flux motors is more superior to that of radial flux motors in this application. Instead of utilizing FEM, the permeance model is employed to model the DSRM. With the analytical expressions, the output torque and current can be obtained dynamically and the geometries of the DSRM can be further optimized. Finally, the hardware-in-the-loop (HIL) simulation environment is constructed to perform full system simulation and the DSRM is shown to be capable of being an auxiliary power source for hybrid scooters.
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  • Ming-Hung TSAI, Ming-Chang SHIH
    2006 Volume 49 Issue 3 Pages 890-896
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    The pneumatic counterweight method is a suitable counterweight method used for machine tool owing to its high speed and force capacity, combined with low price and clean operation. However, the preset pressure cannot be hold at higher traveling rate if the conventional pneumatic counterweight is applied. In this study, rather than using the conventional pressure compensation method, the active pressure control method was designed as an alternative to the pneumatic counterweight driven by a linear motor. The fuzzy sliding mode controller was designed and implemented for regulating the pressure using the servo valve. The experimental results demonstrate that the variation of the pressure in the pneumatic cylinder can be hold within the range ±15kPa by using active pressure control method.
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  • Bui Trong QUAN, Jian HUANG, Minoru HARADA, Tetsuro YABUTA
    2006 Volume 49 Issue 3 Pages 897-904
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    A 3’DOF robot finger is fixed to the end-effector of a 6’DOF robot arm to construct a redundant macro-micro robot system that is able to emulate the finger-arm system of a human being. However, determining joint angles and velocities of a redundant robot system in a natural way remains a difficult issue. This paper describes a method to control the system so as to generate common motions emulating the hand-arm movement of a human. To achieve this purpose, the finger is primarily supposed to complete delicate local motions while the arm moves to assist the finger when the manipulability of the finger is too low and the system is about to miss the desired target. The effectiveness on motion generation and the relation between kinetic energy and manipulability by using the proposed method has been experimentally demonstrated and discussed.
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  • Kanji TANAKA, Eiji KONDO
    2006 Volume 49 Issue 3 Pages 905-911
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    Global localization is the problem in which a mobile robot has to estimate the self-position with respect to an a priori given map as it navigates without using any a priori knowledge of the initial self-position. Previous studies on global localization mainly focused on static environments, where the a priori map is almost correct. On the other hand, in dynamic environments, there are several sources of computational complexity. For example, not only the self-position but also the map should be estimated due to the map errors. The main contribution of this paper is to address such computational complexity by decomposing our global localization problem into two smaller subproblems, and solving the subproblems in a practical computation time. Also, we demonstrate the robustness and the efficiency of the proposed method in various large and complex environments.
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  • Toshiyuki SATOH, Naoki SAITO
    2006 Volume 49 Issue 3 Pages 912-919
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    A method for designing critical systems subject to magnitude-and-rate-limited reference inputs is proposed. The worst-case tracking error is minimized under the constraint on the control effort. The LMI-based technique developed by Chilali and Gahinet is utilized to assign the resulting closed-loop poles into the intersection of a vertical strip and a conic sector. The optimal pole region is searched via the simple genetic algorithm. An illustrative design example of the position control system for a two-inertia system is provided to demonstrate the proposed design method. The simulation and experimental results show that a critical position control system is successfully designed on the basis of the proposed method.
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  • Hong-Sen YAN, Chun-Wei CHEN
    2006 Volume 49 Issue 3 Pages 920-929
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    South Pointing Chariot is one of the important mechanical inventions in ancient China. It achieves the purpose of fixing direction by applying mechanical devices. All existing designs can be classified into two types: “fixed-axis type” and “differential type”. In this study, firstly, the existing designs are analyzed and decomposed into four parts: two inputs, a transmission part, a passive feedback mechanism, and one output. Secondly, because some existing designs have the same topological structures, new representations are used to identify different axial directions of joints and characteristics of members. Thirdly, a design methodology is proposed to systematically synthesize all feasible design concepts of differential-type South Pointing Chariots. Finally, three examples are provided.
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  • Yukihiro ITO, Wataru NATSU, Masanori KUNIEDA, Noriyuki MARUYA, Nobuaki ...
    2006 Volume 49 Issue 3 Pages 930-934
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    This paper describes the error analysis and the repeatability of the shape measurement of thin-large panel by the three-point-support inverting method. In this measuring method, the stable measurement can be carried out because the measured object is supported horizontally by three points. Moreover, the true shape of the measured object can be obtained by cancelling the effects of gravity. However, accurate measurement of the shape of thin-large panel is difficult because there are many error factors originated from both the measuring system and measured object. It was found that the combined standard uncertainty due to the errors caused by the measuring system was 0.408µm and the motion accuracy of the measuring system was the dominant factor. Repeatability of the warp measurement was 0.254µm. Effects of the vibrations of the measuring system and the silicon wafer and the distortion of the silicon wafer due to the friction between the wafer and supports on the repeatability were equivalent. The influence of the data sampling interval was not insignificant when the warp was large.
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  • Jongsoo LEE, Heeseok JEONG
    2006 Volume 49 Issue 3 Pages 935-941
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    The paper describes the development of a decomposition based design (DBD) method using optimal sensitivity information with respect to coupled or interdisciplinary design variables. A multidisciplinary design system considered in the present study is decomposed into a number of subspaces based on their own design objectives and constraints associated with engineering physics. The coupled relations among subspaces are identified by interdisciplinary design variables. Subsystem level optimization is performed in parallel, and the system level coordination is determined by the first order optimal sensitivities of subsystem level objective functions with respect to interdisciplinary design variables. The central of the present work focuses on the formulation of system level coordination strategy and its capability in decomposition based design. A fluid-structure coupled design problem is explored as a test-bed to verify the proposed DBD method.
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  • Kader Md. MOHAFIQUL, Hirohisa NARITA, Lian-Yi CHEN, Hideo FUJIMOTO
    2006 Volume 49 Issue 3 Pages 942-949
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    The purpose of this paper is to develop an efficient method to allocate capacity for export-oriented production of apparels using multi-item newsboy problem in developing countries. Export oriented apparel production in developing countries is fully make-to-order. In this article we describe a method that prescribes three-way solutions depending on the firm’s own capacity. Leasing out of capacity is applied when the firm’s capacity is higher than that required for production demand. In an opposite situation, the firm subcontracts or employs overtime to meet the production requirement. In case of unavailability of subcontract production the firm has to adjust its production order with available capacity. Three factors to represent the probability of leasing, overtime and subcontracting have been used in the model. This helps the decision maker to analyze favorable or worse situation planning. Some previously developed heuristics have been modified to solve the constrained problem. A numerical example illustrates the validity of the model and shows that one of the heuristics performs better than all the previous when the resource is scarcer.
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  • Rei HINO, Tetsuya KUSUMI, Jae-Kyu YOO, Yoshiaki SHIMIZU
    2006 Volume 49 Issue 3 Pages 950-956
    Published: 2006
    Released on J-STAGE: March 15, 2007
    JOURNAL FREE ACCESS
    A scheduling problem is formulated in order to consistently manage each manufacturing resource, including machine tools, assembly robots, AGV, storehouses, material shelves, and so on. The manufacturing resources are classified into three types: producer, location, and mover. This paper focuses especially on the role of the buffer, and the differences among these types are analyzed. A unified scheduling formulation is derived from the analytical results based on the resource’s roles. Scheduling procedures based on dispatching rules are also proposed in order to numerically evaluate job shop-type production having finite buffer capacity. The influences of the capacity of bottle-necked production devices and the buffer on productivity are discussed.
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