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Atsushi KADOWAKI, Masataka KOSAKA, Kunisato SETO, Yoichi NAKAZONO, Yos ...
Article type: Article
Session ID: 3911
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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An Optical Wave Microphone System (O.W.M.S) is a new sound measuring device witch dose not need to install a device at measuring point directly like a condenser microphone and to mix particulate materials like Leaser Doppler Velocimetry. Therefore O.W.M.S can measure sound without disturbing sound fields. Study on the reduction of jet noise has already been carried out, and the Perforated Tube could decrease jet noise at high pressures. However at low pressure peculiar sound noises were detected. It is very difficult to identify the source of those noises with ordinary measuring devises. In the present paper, the development of the method to measure the source of these noises by using O.W.M.S has been reported
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Shinya HIROSE, Keizo AWA, Takuzo IWATSUBO
Article type: Article
Session ID: 3912
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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We developed a power assist robot for human motion support to help physically weak person. It is necessary to solve the problem produced by rapid advance of an aging society in Japan. In this study, we aim at power assist system which reduces user's efforts by wearing the robot on their body. This power assist robot is controlled by a neural network. Skin surface Electromyogram (EMG) and angle of elbow are used as input signals of this system. Since EMG shows the activity of working muscles, we can estimate load torque. Experimental results show that this system can estimate this torque and cooperate with human according to assist ratio.
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Masashi Michiue, Tomohiro Ito, Katsuhisa Fujita
Article type: Article
Session ID: 3913
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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For seismic design of piping systems supported by elasto-plastic supports, we propose the optimization method considering not only the integrity of piping systems but also that of supports. In this paper, the optimization of the capacity and the location of supports is studied using genetic algorithm. Piping systems are modeled by beam elements, and elasto-plastic supports are by a bilinear model. In optimization, we propose evaluation criteria focusing on the stress of piping systems, the absorbed energy of supports and the balance of absorbed energy due to each support.
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Yasutomo KANEKO, Kazushi MORI, Masayuki TOMII, Hiroharu OYAMA
Article type: Article
Session ID: 3914
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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The reduction effect on the vibratory stress of the steam turbine blade with the multi-resonance is studied theoretically for the most probable asymmetric spacing vane, in which the vane count of the upper and lower half is slightly different. The method for the predicting the vibratory stress of the blade for the asymmetric spacing vane is proposed. In order to clarify the validity of the asymmetric spacing vane for the steam turbine, the reduction effects on the vibratory stress in case of applying the asymmetric spacing vane to the existing steam turbine stages are evaluated by using the proposed method.
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Toshihiko KOMATSUZAKI, Hidenori SATO, Yoshio IWATA
Article type: Article
Session ID: 3915
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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The dynamic absorber has been widely used for suppressing vibration in structures. In practical application, the optimal tuned absorbers are designed and used in terms of natural frequency and additional damping so that resultant frequency response becomes fully reduced. However, damping performance of ordinal pendulum system may be influenced by levels of excitation because of intrinsic nonlinearity in system which leads to slight change in natural frequency. The present paper deals with a study of new type pendulum dynamic absorber. It is known that pendulum moving along cycloidal curve strictly keeps uniform period. Both analytical and experimental investigations show that a strict optimal damping condition can be satisfied in cycloid pendulum damper, in conjunction with better damping performance compared with normal pendulum.
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Hiroaki KAWASAKI, Tomohiro ITO, Katsuhisa FUJITA
Article type: Article
Session ID: 3916
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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Recently, various types of high damping materials are widely used for suppressing vibrations in order to develop quit machines and create comfortable life spaces. However, those damping characteristics are generally evaluated experimentally. In this paper, the damping characteristics of a metal are investigated analytically. A dynamical analytical model of steel molecules is established and the molecule behaviors of a metal are investigated in order to study the viblation damping mechanism. Iron is treated here. As a first step, fundamental vibration characteristics and the energy dissipating characteristics are studied in an adiabatic condition for the initial offset condition.
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Yoshinori ANDO, Hitoshi NAGAI, Susumu KOGURE
Article type: Article
Session ID: 3917
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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A robot used indoors is required to be light and small. Such a robot may generate a resonance phenomenon in a comparatively low frequency band. And it may generate oscillations when it is controlled. Therefore we need a way of control which doesn't generate oscillations or reduces the oscillations. This paper we treat a inverted pendulum with flexible joint as a model. We propose a control method for such a model. To design a control, we consider flexibility of joints. A purpose of paper is showing effectiveness of the proposed control method by simulations and experiments.
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Tsutomu KAIZUKA, Nobuo TANAKA
Article type: Article
Session ID: 3918
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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This paper deals with global reduction of noise in an enclosure using both multi microphones and multi speakers. Here, this kind of control system is termed MIMO. Conventional ANC based on MIMO results in heavy computation load for control algorithm. That is trade-off between MIMO and CPU load. In the present study, breakthrough of the trade-ofif is supposed. The control methodology is based on operating microphones and speakers organically. Consequently, virtual SISO is generated in the control system which presented in this paper. Hence, this control system results in much lighter CPU load than conventional MIMO, and is compatible between MIMO and low CPU load.
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Qin ZHU, Mitsuaki ISHITOBI, Shang LIANG, Masayuki YOKOYAMA
Article type: Article
Session ID: 3919
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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A new sliding surface which is constructed by quadratic functions is presented to control a SISO nonlinear dynamical system with parameter uncertainties and external disturbances. Based on the new sliding surface, a design scheme for control of two-degree-of-freedom rigid manipulators is proposed. A numerical simulation shows that the proposed method has improved the system performance in terms of elimination of reaching phase and robustness to disturbances.
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Takashi FUJIMOTO, Kazuhiro TURUTA, Yoshiyuki UCHIDA
Article type: Article
Session ID: 3920
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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This paper deals with a motion control problem of a uni-axial ball-screw slide system driven by an AC servomotor. The objective is to control the motion specified by the trapezoidal velocity profile, using the multi-segment sliding mode control method. The method that has been originally proposed by Shyu et al is modified and used in the present study to simplify the control law and to alleviate the chattering phenomenon. The validity of the control law is examined by the numerical simulations and the experiments.
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Takuya Okina, Yuichi Chida, Hironao Shimizu
Article type: Article
Session ID: 3921
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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A digital redesign method which converts continuous control systems into digital control systems is considered. In this paper, we propose a discretization method by matching of frequency response. Two procedures are proposed in order to guarantee the stability of a discretized controller.
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Osami MATSUSHITA, Hiroyuki FUJIWARA
Article type: Article
Session ID: 3923
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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For rotordynamics design calculations, we have been developing a tracking solver based upon the sliding mode control. Our solver can continuously follow the varying behavior of the characteristic root of dynamical systems caused by a parameter change. By assuming the bearing stiffness or the rotational speed as the time parameter t, the solva provide characteristic root λ(t). This solving method is successfully applied to characteristic polynomial equations of M-K-C systems and the transfer matrix systems. In this paper, the overview of this method produced a rather sophisticated modification which is similar to a car following an exact track by steering control. This modified solver, using sliding mode controlled steering is again applied to rotordynamics design calculations. Compared with the conventional solver, this new solver can track the rather complex behaviors of the varying solution. The effectiveness is demonstrated by several cases; non-linear response curves, critical speed map and eigenvalue locus of a 3 disc rotor supported by oil-film bearings.
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Akira MAEKAWA, Michiaki SUZUKI, Katsuhisa FUJITA
Article type: Article
Session ID: 4024
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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This paper reports on the investigation of coupling effect between beam vibrations and oval vibrations on a cylindrical water storage tank, which are excited by large amplitude sinusoidal waves. Some large amplitude sweep tests with the different magnitudes of input acceleration have conducted for a test tank. Their transfer functions showed that the predominant frequency of resonance curve had shifted to lower frequency region and the magnification factor had gotten smaller as the magnitude of input acceleration increased more. These results of vibration tests have proved that the coupling effect between beam vibrations and oval vibrations reduced the flexural rigidity of the beam vibration of a tank.
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Hiroyuki KAJIYA, Tomoyuki KOMURA
Article type: Article
Session ID: 4025
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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In this paper we describe how to use the finite element method (FEM) in development of flat panel display (FPD) product equipment. Nowadays the size of mother-glass used in production of FPD is growing rapidly. So FPD product equipments are being required not only the rising of basic performance but also the enlargement of equipment and reduction of the process time. To satisfy these requirements, we used the FEM to develop the resist coater, which is one of key FPD product equipment. At first we tried to construct the models of mechanical parts like ball-screw and non-linear vibration region. In these processes, we used spring-damper elements. And we could confirm that these models are effective. And then we constructed the full size model of resist coater with mechanical parts models consist of spring-damper elements and other models confirmed by modal analysis. With that model, we could predict, improve and produce the high performance next-generation resist coater.
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Akihiko HIGASHI, Fumihiro MIZUGUCHI
Article type: Article
Session ID: 4026
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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The purpose of this paper is to investigate the possibility of identification of thickness of a beam by the vibration energy flow analysis. The vibration energy flow is expressed by the structural intensity. In this paper we use a beam with suddenly changed cross-section. Then, we investigate that the suddenly changed cross-section of beam influence on the structural intensity. As a result, it is possible to identify the thickness of the beam by using the structural intensity.
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Hiroshi INOUE, Nobuo TANAKA
Article type: Article
Session ID: 4027
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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This paper deals with a board speaker using a direct velocity feedback method. There are some board speakers being developed now. But it is difficult to put out the bass by using a board speaker. It is the purpose of this paper to make a new thin board speaker by using unconventional tactics. First, the direct velocity feedback method is described by using equation of simply supported plate. Next, the acoustic power is described about the relation of vibration velocity of the plate. Finally, the solution was verified by the numerical analysis.
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Kouji OSHIMA, Takuo NAGAMINE, Yuichi SATO
Article type: Article
Session ID: 4028
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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This paper describes experimental results of friction induced vibrations of flexible vertical shaft. The rotating vertical shaft is supported at an intermediate position. In this study, backward whirling motion of the shaft is observed. From frequencies analysis dominant frequencies of the observed vibrations are natural frequencies of the flexible shaft. The vibrations occur only in the range natural frequency increases, as the span of support increases.
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Youji OKANO, Takuo NAGAMINE, Yuichi SATO, Shigeki MORII
Article type: Article
Session ID: 4029
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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We studied experimentally stick-slip vibrations occurred at rubber seal. Stick-slip vibrations are generated by the frictional force at rubber seal, as steel plate moves slowly. The triangular wave form which includes the vibration of natural frequency of system is observed. From our study the relationships among the frequency of stick-slip vibration, speed of steel plate and load to the rubber seal are clarified.
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Naotoshi OKAYA, Tomohiro ITOH, Katsuhisa FUJITA
Article type: Article
Session ID: 4030
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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The conventional studies on the granular material impact dampers, rarely take the dependency of restitution coefficient on relative impact velocity due to elasto-plastic deformation at the impact into consideration. In this paper, elasto-plastic materials such as lead are treated. The elasto-plastic behavior at the impact is modeled as a bi-linear type force-deformation characteristics. Impact behaviors in the horizontal and vertical plane are evaluated by numerical simulations, and the viblation mitigation capability is investigated.
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Takayuki USUDA, Mitsuru IKEDA
Article type: Article
Session ID: 4031
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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It is proposed to improve the dynamic model of pantograph in which the degree of freedom is increased and the effects caused by contact wire deviation, a pantograph-head interval and the pitching mode of a pan-head support can be examined. In addition, a technique to improve the compliance characteristics of pantograph such as shifting the natural frequency of a pantograph-head has been proposed, and the model calculation and experiments have confirmed the validity of our proposal. Furthermore, technique for selecting optimum value of spring constant using Genetic Algorithm has been proposed.
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Shigeru AOKI
Article type: Article
Session ID: 4032
Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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Collision characteristic is observed at joints of the structures. A practical estimation method of the first excursion probability of such structures subjected to random excitations such as seismic motions is proposed. First, the first excursion probability of structures with collision is obtained from theoretical method. Next, when the tolerance level is normalized by the expected value of the maximum response of the structure without and with collision, the first excursion probability can be estimated independent of natural period and clearance, respectively.
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Article type: Appendix
Pages
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Published: September 18, 2005
Released on J-STAGE: August 01, 2017
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