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Volume 40, Issue 10
Displaying 1-13 of 13 articles from this issue
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Hiroyuki SASAKI, Yuzuru KUBOTA, Kazuhiro WATANABE2004 Volume 40 Issue 10 Pages 981-987
Published: October 31, 2004
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA displacement sensor has been developed using a hetero-core spliced fiber optic element in a form of simple module structure and evaluated in terms of the accuracy, reproducibility, and sensitivity as a new displacement sensitive detector, for the purpose of the full-scale environmental monitoring. The developed sensor module is designed to be sensitive to a relatively large displacement in the range 0-5mm, for which a simple displacement-macrobending conversion mechanism in the module produces as the change in the sensor transmission loss ranging from 0 to a few dB. The experiment promisingly showed the sufficient reproducibility for its sensing operation with the accuracy less than 0.1% to the full span displacement of 5mm. Experiments have been made on the tandem connection of this sensors in a single fiber line, in which accuracy degradation has been elucidated in terms of the reduced S/N ratio for the OTDR measurement brought by tandemly connected sensors in the upstream of a sensor of interest. Discussions are also given on OTDR-based tandem-connection use and on required conditions associated with the averaging time, pulse width, and cursors setting from the practical point of view.View full abstractDownload PDF (1622K) -
Yosuke TSUCHIYA, Yasushi MIKI2004 Volume 40 Issue 10 Pages 988-993
Published: October 31, 2004
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe present a new method for estimating the delay time of a minimum-phase system with delay. It is based on the Hilbert transform relationship between the log magnitude and the phase of a minimum-phase system. An extrapolation procedure for the frequency characteristics is required to describe a discrete causal system which corresponds to the actual continuous system. The algorithm for the extrapolation is improved to stabilize the frequency characteristics, and further, bi-directional extrapolation procedure is presented.View full abstractDownload PDF (1513K) -
Ayako SAWADA, Taketoshi YOSHIDA, Hiroyuki KURODA, Takashi OYABU2004 Volume 40 Issue 10 Pages 994-999
Published: October 31, 2004
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSPlant has the capability to remediate the earth environment. Especially, it has high purification capability for air-pollution. In this paper, the capabilities of golden pothos and peace lily were experimentally examined. The subjects were planted in the plant pot. In the experiment, these subjects were installed in an experimental chamber of 300 liters respectively and the purification processes were monitored by a tin oxide gas sensor. The sensor can detect the concentration of air-pollutants. This sensor output reached at peek level for the concentration of an air-pollutant when it was injected into the chamber by a micro-syringe. The level decreased gradually because the concentration decreased by the plant purification capability. The sensor responding characteristic, which means a plant purification capability, keeps the first order system. The time constant was estimated from the measurement data. The derived data from a modeled dynamics using the time constant was almost correspondent to the measurement one. Therefore, the time constant is employed to evaluate the plant capability. The capabilities of golden pothos and peace lily were nearly constant even if the formaldehyde concentration was changed. The capabilities were examined at the concentration of 5ppm, 6.5ppm, 8ppm respectively. The capability of golden pothos was higher than the one of peace lily and the time constant was about two thirds. Three different sized golden pothoses, which were planted in the same dimension-pots, were also examined. As for a result, the purification capability became higher as an estimated leaf area was larger.View full abstractDownload PDF (2525K) -
Toshihiro SHINOHARA, Jun-ya TAKAYAMA, Shinji OHYAMA, Akira KOBAYASHI2004 Volume 40 Issue 10 Pages 1000-1007
Published: October 31, 2004
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, a novel method for analyzing a woven fabric structure, particularly a multi-layered one, is proposed to obtain positional information regarding each yarn of a sample woven fabric using X-ray computed tomography (CT) images. It can reconstruct a positional relationship between the yarns. The positional information is defined as a sequence of points on the center line of each yarn of the sample in this study, since the sequence can be regarded as the representative position of the yarn and robust against measurement errors. The sequence is obtained by estimating the center of the yarn cross-section of the same yarn at each of the CT images in succession. The center of the yarn cross-section is estimated by correlating the CT image with a yarn cross-sectional model. The effectiveness of the proposed method is confirmed by experimentally applying the method to CT images of a twill fabric. Furthermore, the experimental results of applying the method to CT images of a double-layered woven fabric indicate that even if this method is applied to a multi-layered woven fabric, the correct location of each yarn of the fabric can be estimated.View full abstractDownload PDF (3915K) -
Tatsuya FUNAKI, Kenji KAWASHIMA, Toshiharu KAGAWA2004 Volume 40 Issue 10 Pages 1008-1013
Published: October 31, 2004
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe unsteady flow rate measurement of gases is very important in various industrial fields. In this paper, we examined theoretically and experimentally the static and dynamic characteristics of a laminar flow meter for gases. We confirmed the flow meter can measure oscillatory flow lip to 50[Hz] and the laminar flow meter has phase-lead characteristic theoretically and experimentally. The laminar flow meter with high speed response which is calibrated dynamically can be used for precise pressure control circuits.View full abstractDownload PDF (2372K) -
Ikuro MIZUMOTO, Ryuji MICHINO, Yuichi TAO, Makoto KUMON, Zenta IWAI2004 Volume 40 Issue 10 Pages 1014-1023
Published: October 31, 2004
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper deals with a controller design problem for time-varying nonlinear systems with a higher order relative degree. A robust adaptive tracking control for uncertain time-varying nonlinear systems with stable zero dynamics will be proposed based on the high-gain adaptive output feedback and the backstepping strategies. The proposed method is useful in the case where only the output signal is available.View full abstractDownload PDF (1279K) -
Application to the Underactuated Axisymmetric SpacecraftYasunobu HITAKA, Masahiro YOKOMICHI, Michio KONO2004 Volume 40 Issue 10 Pages 1024-1029
Published: October 31, 2004
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe feasible trajectory generation method for the systems with flat outputs by using low order polynominal may result the degradation of the control performance. In this paper, we propose a method of generating the flat outputs trajectories by using the piecewise smooth functions. Moreover, we optimize these trajectories to improve the control performance of the system. We apply our method to the attitude control of the underactuated axisymmetric spacecraft and examine the effectiveness by numerical simulation.View full abstractDownload PDF (1511K) -
Junichiro SAHASHI, Tatsuo NARIKIYO2004 Volume 40 Issue 10 Pages 1030-1037
Published: October 31, 2004
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper a new method for controller synthesis of the underactuated manipulator is proposed. Basic idea of this method is to combine passive velocity field control (PVFC) with decoupling vector field. Passive velocity field control is an effective control method for fully actuated mechanical systems. However it has been never applied to the underactuated mechanical systems. In order to apply PVFC to the underactuated mechanical systems decoupling vector field is combined. Desired velocity vector field for the PVFC is designed by the decoupling vector field. The PVFC with the decoupling vector field makes the underactuated manipulator track to the desired velocity vector field. In order that the underactuated manipulator can be stabilized at the desired position after tracking to the desired velocity vector field, some control strategies are proposed. In order to demonstrate the usefulness the proposed control strategies are applied to the underactuated 3 link manipulator. Several simulations show the usefulness of the proposed control system.View full abstractDownload PDF (1668K) -
Guarantee of Stability by Common Lyapunov FunctionYoshikatsu HOSHI, Mitsuji SAMPEI, Shigeki NAKAURA2004 Volume 40 Issue 10 Pages 1038-1045
Published: October 31, 2004
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSTime-State Control Form was proposed as one of the control method for nonholonomic systems. But this method needs input switching, so discrete dynamics to ensure stability of the systems should be considered. From the above backgrounds, this paper considers stability conditions of the control method based on Time-State Control Form from the viewpoint of hybrid systems. In this paper, the control objects are limited to chained system, which is one of the canonical forms of nonholonomic systems. Then the stability conditions which are independent of switching conditions are shown by introducing the Lyapunov functions which are invariant to input switching.View full abstractDownload PDF (1905K) -
Tetsuya TABARU, Seiichi SHIN2004 Volume 40 Issue 10 Pages 1046-1053
Published: October 31, 2004
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper shows that the wavelet based dead time measurement method, which has been already studied for open loop systems, is also applicable to closed loop systems. The method measures a dead time of an LTI system from a wavelet transform of a cross correlation function between its input and output. At first, we derive the cross correlation function and its cross spectrum for the closed loop case. Next, its wavelet transform is analyzed under certain conditions by using the relation among a wavelet transform of a correlation function and the corresponding spectrum, which we have been already studied. The analysis shows that the dead time is also measurable for the closed loop case although the cross correlation function, the cross spectrum and the wavelet transform have more complicated forms than the open loop case.View full abstractDownload PDF (1968K) -
Ichijo HODAKA, Ichiro JIKUYA2004 Volume 40 Issue 10 Pages 1054-1059
Published: October 31, 2004
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes stabilizing continuous-time linear periodic state feedback control laws for continuous-time linear periodic systems. The feedback control laws, under some assumption, enable to construct closed-loop systems which approximate intended linear time-invariant systems, as well as stabilize them. This approximation permits a clear forecast for shaping of initial response. The key to the proposed method is raising frequency of closed-loop periodic systems, which enables to utilize the theory of averaging for analyzing periodic systems.View full abstractDownload PDF (1386K) -
Reduction of Contact Forces on a Human Body and Vibration ControlTaro NAKAMURA, Norihiko SAGA, Masaru NAKAZAWA, Takashi KAWAMURA2004 Volume 40 Issue 10 Pages 1060-1066
Published: October 31, 2004
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSRecently, as robots and humans have increasingly come to share common spaces especially in the fields of the medicine and home automation, it has become necessary to consider the frequent physical contact of robots and humans. However, many robot joints have actuators with high-ratio gear trains. Therefore, when this type robot comes in to human contact, such a robot may cause pain.
This study describes the development of a manipulator using a smart flexible joint composed of an ER fluid. Further, a torque controller designed in light of human pain tolerance is applied to the soft manipulator. Simulation and experimental results demonstrate the effectiveness of the manipulator.View full abstractDownload PDF (2593K) -
VIET NGUYEN Thang, Takehiro MORI, Yasuaki KUROE, Yoshihiro MORI2004 Volume 40 Issue 10 Pages 1067-1069
Published: October 31, 2004
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper studies the problem of the relations between existence conditions of common quadratic and those of com-mon infinity-norm Lyapunov functions for sets of continuous-time linear time-invariant systems. Based on the equivalence between the robust stability of a class of time-varying systems and the existence of a common infinity-norm Lyapunov function for the corresponding set of linear time-invariant systems, the relations are determined. It turns out that although the relation is an equivalent one for a single stable system, the existence condition of common infinity-norm type is implied by that of common quadratic type for a set of systems. Several existence conditions of a common infinity-norm Lyapunov are also presented for the purpose of easy checking.View full abstractDownload PDF (518K)
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