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Volume 41, Issue 2
Displaying 1-14 of 14 articles from this issue
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Shogo TANAKA, Daisuke SUGA2005 Volume 41 Issue 2 Pages 95-101
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSNon-destructive inspection by the electromagnetic wave (Radar) conventionally makes use of the shaded image on the magnitude variation of the reflected waves, i.e., B-mode images, and the anomaly diagnosis has been qualitatively done based on inspector's eye. This yields the diagnosis of a low reliability and a low accuracy.
The paper proposes a diagnosis method of high reliability and high accuracy based on the received signal obtained as time-series one. The method compares the peak pattern of the received signal with the predicted one based on a signal propagation model and realizes a high reliable non-destructive inspection of reinforced concretes.View full abstractDownload PDF (2462K) -
Yuichi IKEDA, Takashi KIDA, Tomoyuki NAGASHIO2005 Volume 41 Issue 2 Pages 102-110
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we consider control of nonlinear mechanical systems by symmetric controller (DDFB controller). Firstly, we discribe DDFB controller for linear mechanical systems. Secondly, we show that nonlinear mechanical systems are stabilized by DDFB controller. Especially, we also show that for underactuated systems DDFB controller is a class of Euler-Lagrange (EL) controller for underactuated systems and that it is a special class of strict positive real based dynamic output controller to control EL systems. Finally, obitained results are verified by simulations.View full abstractDownload PDF (1502K) -
Wataru KITAMURA, Yasumasa FUJISAKI2005 Volume 41 Issue 2 Pages 111-117
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSMinimax estimation is considered for a single-input single-output discrete-time uncertain system in the presence of bounded disturbance. The given regressors are divided into two sets which have small and large amplitudes respectively, where the amplitude ranges are assumed to be exclusive each other. Then, the nominal parameter of the system is estimated so that the maximal output error is minimized. The bounds of the disturbance and the parameter uncertainty are also estimated by using the output errors for these two sets. For this minimax estimation, the estimation errors are evaluated when the regressors of each set are persistently exciting. Furthermore, probabilistic estimation errors are derived when the regressors of each set are persistently exciting and periodic and have the same amplitude, and the disturbance and the parameter uncertainty are random variables which take their extreme values with a probability. The result implies that the errors converge to zero as the number of samples tends to infinity.View full abstractDownload PDF (1552K) -
Hiroki KASAI, Yasuaki OISHI2005 Volume 41 Issue 2 Pages 118-125
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSStabilizability and stabilization are considered on a first order system whose dynamics stochastically changes subject to a Markov chain. Although a necessary and sufficient condition is known for the stabilizability, it is not convenient in the sense that it can be checked only through minimization of a non-convex function. In this paper, a more convenient sufficient condition is presented, which is based on conditional variance. It is also shown that a control law simpler than the known one stabilizing the system when the presented condition is satisfied. These results are considered to be useful for better understanding of stabilizability and stabilization of such systems.View full abstractDownload PDF (1265K) -
Masahiro SHIMIZU, Toshihiro KAWAKATSU, Akio ISHIGURO2005 Volume 41 Issue 2 Pages 126-134
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper discusses a fully decentralized algorithm able to create a coherent swarm of autonomous mobile robots from the viewpoint of “computational physics”. To this end, we particularly focus on the “Molecular Dynamics method” and the “Stokesian Dynamics method”, both of which are widely used to investigate manybody systems. To verify the feasibility of our approach, this idea has been implemented to a swarm of 2-D radio-connected autonomous mobile robots as a practical example. Simulation results indicate that the proposed algorithm can control the shape of the swarm appropriately according to the current situation without losing the coherence of the swarm nor exchanging any global information among the modules. Furthermore, we have found that the local interaction which is used to exploit Stokesian Dynamics plays an essential role in order to maintain the coherence of the swarm particularly under an unstructured environment.View full abstractDownload PDF (3698K) -
Yohji KOBAYASHI, Yasumasa FUJISAKI, Masao IKEDA2005 Volume 41 Issue 2 Pages 135-141
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper presents an approximated DVDFB control by a strictly proper controller using the displacement output for large space structures with sensors/actuators collocation. The control law consists of a second order filter and PD feedback of the measured displacement. The second order filter is connected at each control input channel in order to make the controller strictly proper. It is shown that the closed-loop system becomes stable and optimal for a frequency-dependent quadratic cost function by choosing the filter parameters and the feedback gains appropriately.View full abstractDownload PDF (1347K) -
Yasushi OKADA, Shuichi ADACHI, Jan M. MACIEJOWSKI2005 Volume 41 Issue 2 Pages 142-148
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, system identification problem in which input and output data are measured by using sensors with static nonlinearity, such as saturation, dead zone, and so on. A novel system identification method which estimates sensor erros due to its nonlinearity, as well as system parameters, is proposed. The key idea is to formulate the identification problem as a constrained optimization problem. Then the system parameters are estimated by using quasi-Newton method. The effectiveness of the proposed method is examined through numerical experiments.View full abstractDownload PDF (1701K) -
Masami SAEKI2005 Volume 41 Issue 2 Pages 149-156
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA numerical optimization method of multivariable PID controllers that satisfy the performance index of the standard H∞ control problem is proposed. Since the problem is described as a bilinear matrix inequality of PID gains for each frequency, a new method of obtaining a sufficient condition in the form of a linear matrix inequality is proposed. The PID gain converges by solving the LMI problem iteratively starting from a stabilizing PID controller, while the H∞ norm decreases monotonically. Controller structure constraints such as decentralized control can be readily treated in the framework.View full abstractDownload PDF (1929K) -
Takafumi MATSUMARU, Kiyoshi HAGIWARA, Tomotaka ITO2005 Volume 41 Issue 2 Pages 157-166
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper examines the combination control of the manual operation and the autonomous motion to improve the maneuverability and safety on teleoperation of mobile robot. The autonomous motion which works to support the manual operation processing information from simple range sensors on mobile robot is examined with using a computer simulation. Three types of autonomous motion, revolution (RV), following (FL), and slowdown (SD), are proposed and the way to be equipped on the system are examined. In revolution, robot turns autonomously when robot approaches some obstacle too much. In following, robot translates parallel keeping its orientation to go along the form of the obstacle. In slowdown, robot is restricted its translation speed according to the distance to the obstacle and the translation speed of the robot. Features of each autonomous motion is declared; transit time and mileage become shorter with the revolution or the following, and the contact between robot and obstacle is almost avoided with the slowdown. When the distance to some obstacle to apply some autonomous motion is adjusted depending on the translation speed of the mobile robot, too much addition of autonomous motion against operator's intention is reduced so the maneuverability can be improved. When the revolution or the following is incorporated with the slowdown, even though the transit time is prolonged, the number of near miss for the robot to some obstacles is reduced so the safety can be improved.View full abstractDownload PDF (3469K) -
Yoshiyuki TANAKA, Satoshi NODA, Toshio TSUJI, Masaharu MARUISHI, Hiroy ...2005 Volume 41 Issue 2 Pages 167-173
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes a virtual EMG-prosthetic hand system using a neural network available in functional MRI environments for developing an effective training system of amptees. An operator attaches a set of surface electrodes on his forearm, and manipulates the virtual EMG-prosthetic hand visualized with 3D computer graphics projected on a screen in the scan room. The preliminary experiments demonstrate that the hand motion a subject intended can be determined with high discrimination rates without decaying fMRI images. Then, the validity of the proposed system was comfirmed through the neurological experiments that were carried out to analyze human brain functions in operating the hand system.View full abstractDownload PDF (4225K) -
Ryouji DOIHARA, Yoshiya TERAO, Masaki TAKAMOTO2005 Volume 41 Issue 2 Pages 174-176
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe investigate the possibility of further improvement of sensitivity by adopting acceleration sensors. A flow tube has been fabricated and subjected to basic experiments in order to confirm the characteristics of the measurement system.View full abstractDownload PDF (603K) -
Masakazu KOTAKI, Takanori YAMZAKI, Tadahiko MATUBA, Kazuyuki KAMIMURA, ...2005 Volume 41 Issue 2 Pages 177-179
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper describes tuning PID controllers for a plant approximated by a first-order lag plus deadtime system using optimization. Graphs by which the optimal PID parameters can be obtained are presented as functions of a normalized deadtime and a perturbation of plant characteristics caused by changes in dynamics. To evaluate the control performance, the disturbance suppression and the reference tracking properties are presented compared to those by the partial model matching method designed for the same plant. It is found that the effectiveness of the proposed tuning method is shown by simulations.View full abstractDownload PDF (446K) -
Hisao KATOH, Katsuhiko FUWA2005 Volume 41 Issue 2 Pages 180-182
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we deal with the sensitivity design problem of the two-degree-of-freedom type-1 servosystem. The class of the feasible sensitivity function is clarified. It is also shown that such sensitivity design can be easily carried out on the Bode diagram. The significance of our method is shown by numerical simulations.View full abstractDownload PDF (506K) -
Hisayoshi SUGIYAMA, Tetsuo TSUJIOKA, Masashi MURATA2005 Volume 41 Issue 2 Pages 183-185
Published: February 28, 2005
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA method is proposed for wide area search by victim detection system. In the victim detection system, robots configure the ad hoc network and search victims maintaining autonomously the communication path to MS (monitor station). Each robot selects its role between HR (head robot) and RR (relay robot) according to its FT (forwarding table). HR explores the disaster area whereas RR plays as a relay terminal connecting MHR (master HR) and MS. MHR is selected properly among HRs recorded in the FT at each RR. The effectivity of this method is confirmed by omputer simulations.View full abstractDownload PDF (466K)
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