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Volume 49, Issue 12
Displaying 1-15 of 15 articles from this issue
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Special Issue on Sensing Technology for the Next Generation
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...2013 Volume 49 Issue 12 Pages 1085
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSDownload PDF (166K)
Paper
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Katsuhiko TABATA, Toshiaki IWAI, Shigeki KUDOMI, Yoshimichi ENDO, Yosh ...2013 Volume 49 Issue 12 Pages 1086-1091
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSWe develop an ultrasonic positioning system for navigation of automated guided vehicles (AGV) available to be used not only indoors but also outdoors and adaptable to a temporary route. Then AGV drives along setup route, the sonar system mounted on AGV communicating with the land marker composed of ultrasonic transducers by the handshake protocol and measuring relative position against the marker at same time. The sonar system is equipped with the phased array of the ultrasonic sensors to improve the signal-to-noise ratio. Assignment of the 7-bits ID to the land marker reduces the influence of the ultrasonic interference. We need more improvement of the system performance under the degradation, such as false detection and reduction of estimate accuracy of the marker position, ascribable to superposition of multiply-reflected signal. In this paper, we investigate the response of the marker with the long time delay to suppress the influence of the multiple reflections. We compare experimental results for the land markers with the short and long time delays and confirm the effectiveness of our proposal.View full abstractDownload PDF (2800K) -
Nobuhiro SHIMOI, Hirokazu MADOKORO2013 Volume 49 Issue 12 Pages 1092-1100
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSIn the near future as a serious aging society, we will have more medical and nursing care problems for old people. As one means such a problems solves, we would like to propose a novel system using high quality combination sensors to bed monitoring technology. As an important example of such support, a QOL (Quality of life) monitoring system for aged people and patient are proposed for helper request. We originally developed plate shaped sensors and pillow sensor using piezoelectric elements and 3-dimension accelerometer. Existing sensors such as clip sensors or mat sensors require restraint of patients. Moreover, these sensors present privacy problems. The features of our sensors are that they require no power supply or patient restraint. We evaluated our system using a basic experiment to predict seven behavior patterns. We obtained a result of predicted behavior patterns related to bed-leaving using only six sensors installed under a bed or pillow sensor on a bed. Especially, our system can correctly detect behavior patterns of lateral sitting, which is a position that occurs when a patient tries to leave from the bed, and terminal sitting, which is the position immediately before bed-leaving. They were discerned from other behavior patterns.View full abstractDownload PDF (1787K) -
Yuki MIYAUCHI, Hiroaki ISHIZAWA, Masaaki NIIMURA2013 Volume 49 Issue 12 Pages 1101-1105
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSNeeds for vital sign measurement systems have been increasing. Non-invasive and non-restraining systems are required that it can monitor health status over a prolonged period. In this study, we use FGB (Fiber Bragg Grating) sensors. We have devoted significant efforts in developing a vital sign measurement system that can address the above-described problems. Using an FBG sensor, we acquired waveforms of strains from the body surfaces. These waveforms are pulse waves caused by the expansions and contractions of arteries. We used the waveforms to determine the respiratory and pulse rates. As a result, the principles of vital sign measurements by the FGB sensors have been confirmed.View full abstractDownload PDF (1362K) -
Hisao FUKUMOTO, Isao KURATOMI, Tatsuya FURUKAWA, Masashi OHCHI, Hideak ...2013 Volume 49 Issue 12 Pages 1106-1112
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSIn this paper, the authors propose a training system for unvoiced vowel recognition. In the unvoiced vowel recognition system, three pairs of electrodes were placed on the facial muscles and Surface Electromyogram (SEMG) signals were recorded. The vowel is recognized by the binary pattern which is calculated from the activity values of the measured SEMG signals using thresholds. However, the recognition accuracy was low for some speakers who were not able to adapt themselves to the stable movement of the facial muscles for unvoiced speech. To address this issue, the activity values measured from multiple speakers were classified using Self-Organizing Map (SOM) algorithm and the classification results determined the standard pattern of the activity values for each vowel. The proposed training system visualizes the similarity between the measured activity pattern and the standard activity pattern by displaying each activity pattern's position on the self-organized map. Experimental results of 16 speakers showed that the learning rate of the proposed training system was superior to our previous system in which only the recognition result was provided by the character and the sound.View full abstractDownload PDF (1440K)
Paper
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Hiroya GOTO, Koichi SAGAWA2013 Volume 49 Issue 12 Pages 1113-1120
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSThis study investigates the estimation method of the human postural control ability while inclination and recovery in the sagittal plane and proposes an evaluation method of standing stability. One-link inverted pendulum model is applied to the human body and ankle joint torque is assumed to be generated based on time variant PID control method using tilt angle of the body. The subject is asked to stand still, incline forward as far and quickly as possible, and return to the original posture with subjects' eyes-opened, eyes-closed, and one-legged to simulate unstable condition of standing posture with visual disturbance and muscle weakness, respectively. Tilt angle in the sagittal plane is measured using optical motion capture system. Time variant PID gains are estimated according to the standing condition applying fixed trace method because conventional sequential least square method is affected by small noise of the tilt angle of body while standing still continued for a several seconds. Eleven healthy young subjects participated in the experiment and experimental results show that the body inclination is carried out by destabilizing the control system of standing posture and muscle weakness and visual disturbance are characterized by P-gain and D-gain, respectively. Estimated parameter variations are able to distinguish standing stability between three standing conditions.View full abstractDownload PDF (1070K) -
Tomoharu SUEHIRO, Kenji MASUI, Toru NAMERIKAWA2013 Volume 49 Issue 12 Pages 1121-1130
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSThis paper deals with a decentralized hierarchical control of power networks by using overlapping information. The control objective is to minimize the cost function of load frequency control problem. The control law is constructed through three steps. In the 1st step, we make a hierarchical system with overlapping information. In the 2nd step, a relationship between the original system and the hierarchical system is confirmed. In the 3rd step, the hierarchical decentralized control for the hierarchical system is constructed and the decentralized hierarchical control law is contracted to the original system. Then, we show the effectiveness of the load frequency control by using the proposed control method.View full abstractDownload PDF (1426K) -
Yuki FUJITA, Yoshihiro OKAWA, Toru NAMERIKAWA2013 Volume 49 Issue 12 Pages 1131-1138
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSThis paper discusses cyber attacks and faults diagnosis method for networked electrical power systems. A power system is divided into some areas, then phase angles and angular frequencies are estimated by Kalman filter in each area. Then we propose a diagnosis method for the power grid by using state and output fault diagnosis matrices which are composed of the estimate value and output matrix. These diagnosis matrices can immediately reflect an existence or non-existence of abnormal signal. Finally we show simulation results to analyze effectiveness of the proposed method.View full abstractDownload PDF (708K) -
Tomoyuki NAKAO, Ryota SAKAMOTO, Ken'ichi YANO, Naoki KUBOTA, Naruto MI ...2013 Volume 49 Issue 12 Pages 1139-1146
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSCreative activities, such as painting and music, are one source of satisfaction and fulfillment for people with disabilities. However, some individuals with disabilities cannot satisfactorily enjoy such activities due to involuntary movement. In this study, we developed a drawing assist system and prevention control of error-drawing for nonperiodic involuntary movements. Drawing assist system has position correction filter to attenuate involuntary movement on the basis of characteristics of it. It is suggested that error-drawing is caused by imbalance in involved muscles. Prevention control of error-drawing is based on impedance control and suppresses involuntary movements. Our system enabled drawing based on the participant's own senses and motor control, even when experiencing involuntary movement.View full abstractDownload PDF (2573K) -
Masanobu KOGA, Takahiro ESUMI, Kentaro YANO2013 Volume 49 Issue 12 Pages 1147-1153
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSThis paper proposes a method which gives symbolic model of the interconnected linear system using the adjacency matrix which represent the system. When there exist any algebraic loops in the system, they are reduced to the self loops by the edge contraction. If the weight matrix of the self loop is nonsingular, it is removed and the symbolic state space model is obtained, otherwise the symbolic descriptor model is obtained. We introduce a new interactive graphical software tool which have been developed for modeling and simulation of control systems using the proposed method.View full abstractDownload PDF (688K) -
Daisuke TSUBAKINO, Taiki YOSHIOKA, Shinji HARA2013 Volume 49 Issue 12 Pages 1154-1163
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSLarge-scale dynamical systems often consist of a number of subsystems that are interconnected according to a hierarchical multi-scale network. This paper introduces a hierarchical control scheme as an efficient strategy to handle such systems and proposes a method for designing a hierarchical linear quadratic optimal regulator. The proposed framework employs an algebraic approach. We first characterize a hierarchy of systems as an algebra based on semigroups, the Kronecker product, and the linear combination. This allows us to prove that the stabilizing solution of the Riccati equation inherits a hierarchy if system matrices and weights in the cost function belong to the corresponding common algebra that characterizes the hierarchy. A couple of classes of systems that can be treated by our algebraic framework are also provided in the paper. We will see that the derived result gives a unified insight into several related previous works.View full abstractDownload PDF (618K) -
Hiroki MIYAZAKO, Yutaka HORI, Shinji HARA2013 Volume 49 Issue 12 Pages 1164-1171
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSThe dynamics of reaction-diffusion systems with a single diffusible molecule is of great interest in the study of recent synthetic biology. In this paper, we analyze the spatio-temporal dynamics of such systems. Specifically, we classify the spatio-temporal patterns from a control theoretic viewpoint and analytically derive the Turing instability conditions that correspond to the classified patterns. To this end, we first show that the reaction-diffusion systems with a single diffuser can be represented by a SISO system with a constant feedback gain. This then boils the Turing instability analysis down to the root locus analysis problem and allows us to derive the instability conditions using control theoretic tools. As a result, we can point out that at least three reacting molecules are necessary to produce physically plausible spatial patterns unlike the classical activator-inhibitor models with two diffusible molecules. These results are demonstrated on an extended Gray-Scott model with a single diffuser.View full abstractDownload PDF (883K) -
Taiga YAMASAKI, Shunsuke NAKADACHI, Xin XIN2013 Volume 49 Issue 12 Pages 1172-1178
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSThe three-dimensional plot of the time sequences of the elevation angles of the thigh, shank, and foot during human walking has been reported to lie close to a plane, called the planar law showing the intersegmental coordination. For evaluating such coordination, the elevation angle has been regarded as an important coordinate system. However, there exist many other coordinate systems for describing the limb configuration. Even for the same data, the difference of the coordinate system may change the degree of planarity, and also affect the evaluation of the coordination. Here we aim to study the effect of the coordinate system on the planar law. We measure lower limb kinematics during steady walking on a treadmill with various speeds. Then we compare the degrees of planarity of the measured data described in various coordinate systems generated from the measured angles between the vertical and the thigh, the thigh and the shank, and the shank and the foot, and the linear transformations described by regular-three-dimensional matrices composed of elements { 0, 1, -1 }. The result shows that the different coordinate system can lead to a wide range of the planarity, and there exist many coordinate systems yielding higher or lower planarity than the elevation angles. Additionally, we elucidate the mathematical aspects of the planarity that depends on the coordinate systems. It is concluded that the planar law does not necessarily imply the importance of the information described by the elevation angles.View full abstractDownload PDF (1650K) -
Shigemasa NAKAGAWA, Kentaro HIRATA, Kazuyoshi HATADA, Kenji SUGIMOTO2013 Volume 49 Issue 12 Pages 1179-1185
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSThis paper proposes a new controller design method for steel strip cooling in the transition boiling region. The temperature dependence of the cooling process gain is expressed via a nonlinear state space form. The proposed cooling control system is designed as a state feedback controller by applying the SOS (Sum of Squares) technique to the state space model. Simulation results show the effectiveness of the proposed controller for steel strip cooling in the transition boiling region.View full abstractDownload PDF (879K) -
Yusuke OKAJIMA, Kenji HIRATA, Kenko UCHIDA2013 Volume 49 Issue 12 Pages 1186-1195
Published: 2013
Released on J-STAGE: December 21, 2013
JOURNAL FREE ACCESSWe consider a future energy demand network that consists of one utility company and N customers. The utility company purchases energy and sells them to the consumers. In order to optimize the energy consumption the utility company and consumers exchange information and make a schedule of consumption patterns of the whole day previously. In a competitive society selfish consumers' optimization of their own benefits does not generally guarantee maximization of whole network's benefit; in such a case, we say that the network is under the uncertain information environment. We formulate a generic dynamic LQ energy demand network under an uncertain information environment, and propose an optimization-based mechanism that requires the utility company to design an incentive cost (transfer cost) using the VCG mechanism, so that selfish and optimal schedulings of N customers based on their own benefits leads to the whole network's maximum benefit. We demonstrate efficiency of the proposed method by using a numerical example of dynamic 10 customers model.View full abstractDownload PDF (875K)
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