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Volume 35, Issue 3
Displaying 1-22 of 22 articles from this issue
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Toru KINO, Satoshi HONDA, Yutaka TOMITA1999 Volume 35 Issue 3 Pages 305-311
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSChanges in living tissue elasticity or hardness are generally correlated with its pathological state or disease. This makes tissue elasticity information extremely useful for early detection of cancer, coronary heart disease, and liver cirrhosis. But almost all of medical ultrasound examinations are insensitive to hardness as an imaging parameter. Today, therefore, palpation is still widely used as a self-screening procedure for obtaining the tissue elasticity. In recent years, new methods using Doppler based techniques are proposed and have been examined. In their method the approach combines external mechanical stimulation of target tissues with Doppler ultrasound to map the relative tissue motion.
In this study, one dimensional distribution of the vibration amplitude inside the agar phantom is detected by Doppler ultrasound, then the relative hardness of tissues is evaluated by using above mentioned method. First, it was verified that the low frequency vibration amplitude propagated in the homogeneous phantom was almost uniform amplitude. Next, as for the phantom which has relatively “hard” inclusion to surrounding medium, it was shown that the low frequency vibration was shut out at the face of “hard” inclusion. And as for the phantom which has relatively “soft” inclusion to surrounding medium, it was shown that the low frequency vibration was propagated well up to the part of “soft” inclusion to surrounding medium, but it was propagated little in the area which is behind the “soft” inclusion. The phantom with a thickness of about 3cm was used in the experiments, in that case, the frequency of 150Hz was best to distinguish the inclusion from the surrounding medium. In the measurement system made for this study, the inclusion with a thickness of about 5mm was detectable.View full abstractDownload PDF (1834K) -
Nobuaki KOBAYASHI, Mitsuhiro SAKURAI, Yoshiaki OKADA, Takayoshi NAKAMI ...1999 Volume 35 Issue 3 Pages 312-318
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we discuss the property of the limiting form derived from a standard linear optimal regulator problem by letting the weighting matrix tend to zero. It is shown that there exists an explicit relationship between limiting form of discrete-time systems linear optimal regulators and block decoupling control in discretetime systems. Based this property, we present a new procedure for deriving the decoupling control law without calculation of interactors and canonical decoupled form. The block decoupled system with maximum number of blocks is automatically constructed by the proposed designing procedure.View full abstractDownload PDF (1516K) -
Izumi MASUBUCHI, Ayato KUME, Etsujiro SHIMEMURA1999 Volume 35 Issue 3 Pages 319-325
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes an approach to gain-scheduling control systems synthesis based on spline-type parameter-dependent quadratic forms that guarantee stability and performances of systems. We provide a procedure to derive a finite set of LMIs from a given LMI-condition on a parameter-dependent quadratic form. It is shown that (1) if there exists any solution to the derived finite set of LMIs, it produces a differentiable spline-type parameter-dependent quadratic form that meets the given LMI-condition. Moreover, we prove that (2) if there exists any differentiable quadratic form solving the given LMI, the finite set of LMIs with some division of scheduling parameter's region is always solvable. Thus unlike previous results this paper guarantees that employing computation always reduce conservatism in solving parameter-dependent LMIs. This approach is applied to parameter-dependent LMIs for analysis and synthesis of exponential stability and L2-gain performance.View full abstractDownload PDF (1458K) -
A Dissipative Systems Theory ApproachTielong SHEN, Katsutoshi TAMURA1999 Volume 35 Issue 3 Pages 326-332
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we discuss a dissipativity-based approach to robust tracking problem for rigid robot. Parametric uncertainty, modeling errors and unknown disturbance are considered. First, the passivity-based tracking approach is reviewed and it is shown that the approach can be expressed as an application of Lyapunov recursive design method. Then, the approach is extended to the design problems of tracking with disturbance attenuation, robust tracking with disturbance attenuation and adaptive robust tracking. The basic idea is to construct the storage function of dissipation inequality for all uncertainties under consideration.View full abstractDownload PDF (1520K) -
Etsuro SHIMIZU, Kenta KUBOTA, Mitsuji SAMPEI, Masanobu KOGA1999 Volume 35 Issue 3 Pages 333-339
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper shows a design method of a nonlinear controller for linear systems. In order to design a nonlinear controller, we use a nonlinear weight and consider the H∞ control problem. It is shown that, under some constraints on the nonlinear weight, a nonlinear controller can be obtained by solving the Algebraic Riccati Inequality. And some of admissible nonlinear weights are shown. The obtained nonlinear controller is a low (high) gain controller at around the origin, and becomes a high (low) gain controller at far from the origin.View full abstractDownload PDF (1561K) -
Non-Linear, Reduced-Dimension Sliding Mode ControllerHiromitsu KUMAMOTO, Osamu NISHIHARA, Kenji TENMOKU, Hiroshi SHIMOURA1999 Volume 35 Issue 3 Pages 340-348
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA non-linear, reduced-dimension steering controller is derived through a sliding mode control theory for an automobile with unknown parameters driving on a course consisting of smoothly connected arcs. A specific, headway viewpoint is introduced to define deviations from the course, and the controller is proven stable and robust. Stationaly values are calculated analytically. Simulation results are given to demostrate a good performance of the proposed controller. Clothoid connections of arcs further improve the performance.View full abstractDownload PDF (1933K) -
Jun IMAI, Kiyoshi WADA1999 Volume 35 Issue 3 Pages 349-356
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSAn approach is presented for modeling uncertainty from a priori information of a plant. A feasible model set is defined of all systems governed by a class of differential equations with certain norm bounds of unknown input and output operators and partially known eigenparameters. Then an unstructured uncertainty class of models including the feasible model set is characterized with least magnitude of additive perturbation in frequency domain. An example of finite dimensional compensator design is demonstrated to illustrate the usefulness of the approach.View full abstractDownload PDF (1409K) -
Tetsuya TABARU, Seiichi SHIN1999 Volume 35 Issue 3 Pages 357-362
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes a dead time measuring method for a linear system. Around the dead time, an impulse response of the system has self-similarity, which can be detected by the wavelet analysis. The proposing method detects the dead time from wavelet transform of a cross correlation function between an input and an output in order to reject disturbances, if the input satisfies a certain condition and disturbances are small. A numerical simulation shows efficiency of the method.View full abstractDownload PDF (1447K) -
Chemical Reactor ControlMasatoshi NAKAMURA, Kenta SHIRAMASA, Takenao SUGI, Satoshi OHYAMA, Mor ...1999 Volume 35 Issue 3 Pages 363-369
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSNonlinear statics compensated PID based on nonlinear separation control was proposed and applied to chemical reactor control. The PID parameters were determined ideally by a linear control theory because the input signals for the proposed PID controller was compensated by nonlinear statics of the system. The properties of the proposed PID showed the same as that of conventional PID whose parameters were selected in optimal values at any time decay. The proposed PID proved a satisfactory control performance in a computer simulation which reflected actual operation of chemical reactor.View full abstractDownload PDF (1584K) -
Masaki YAMAKITA, Masaru NEGI, Koji ITO1999 Volume 35 Issue 3 Pages 370-377
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWith an increase of needs of tele-operation in several applications, e.g., deep sea or space exploration and tele-surgery, many researchers studied bilateral master-slave tele-operator systems especially after a novel and simple method using a scattering transformation to overcome the instability due to transmission delays was proposed. In this paper we propose a bilateral master-slave manipulator system in which the slave impedance can be adjusted by an operator in a bilateral fashion. The stability of the system for the time delay is also discussed, and the effectiveness of the system is shown by experiments.View full abstractDownload PDF (983K) -
Study on the Effects of Strip Deflection Caused by Flexural Rigidity, Weight and Velocity of the StripNaoharu YOSHITANI1999 Volume 35 Issue 3 Pages 378-383
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper describes the analysis of tension dynamics of steel strip in tandem hot rolling and presents new equations with the effects of interstand strip deflection caused by flexural rigidity, weight and velocity of the strip. The above effects, not considered in existing tension models, are shown to be not negligible. In the analysis, two differential equations, one for tension dynamics and another for strip deflection curve, were first derived based on the theory of the strength of materials. A simple mathematical model for calculating a parameter in tension dynamics was then derived from the differential equation for the deflection curve. The accuracy of the simple model was confirmed to be satisfactory. The obtained equations can be used to increase accuracy in the analysis and simulations of tension behaviors and in online tension control.View full abstractDownload PDF (1338K) -
Noriyuki AKASAKA1999 Volume 35 Issue 3 Pages 384-392
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDynamic positioning systems have been developed to hold the position of platforms and vessels against external disturbances such as winds and currents by using rotating thrusters, in offshore oil exploitations in place of anchoring systems.
In this paper, in order to make an approach for a vessel having a bow- and a stern-thruster to better the dynamic position control for a drastic wind-force disturbance, detailed investigations were carried out on the on-line selection technique of the PID-type controllers' gain sets. Evaluation of the technique was made on the basis of computer simulations by use of ship motion theory and model test results. It is clarified that the technique will substantially provide an efficient way to the better control performance of dynamic positioning systems.View full abstractDownload PDF (1936K) -
Eiichi ONO, Shigeyuki HOSOE, Katsuhiro ASANO, Masaru SUGAI, Shun'ichi ...1999 Volume 35 Issue 3 Pages 393-400
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSVehicle stability control problem which protects the vehicle from spin can be described by robust stabilization problem against perturbations of rear cornering force. The control law of the braking force distribution is designed by using gain-scheduled H∞ control. The designed controller satisfies H∞ norm condition for arbitrary velocity in order to protect the vehicle from spin. The experimental results show that the designed controller robustly stabilizes the vehicle and protects it from spin in the presence of the perturbations of rear cornering force.View full abstractDownload PDF (1455K) -
Umerujan SAWUT, Nobuhiro UMEDA, Tsuyoshi HANAMOTO, Teruo TSUJI1999 Volume 35 Issue 3 Pages 401-406
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we consider an one-link flexible arm of length L. One end of the arm is attached to a motor with the arm axis perpendicular to the motor axis and the other end is attached with a payload. The main purpose is the supression of generation of oscillation in controlling angular position. For the method of control, the sliding-mode control method is applied. Also, a non-linear observer is incorporated with the controller where the observer gains are designed by pole placement method. Finally, simulation results using MATLAB and experimental results are shown for the confirmation of effectiveness of the sliding-mode controller with the non linear observer incorporated.View full abstractDownload PDF (623K) -
Kayo IMAMURA, Kiyotoshi SHINOHARA, Motohide UMANO, Hiroyuki TAMURA1999 Volume 35 Issue 3 Pages 407-414
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we propose a method for extracting of fuzzy rules from data including qualitative attributes such as a country and an item type. These rules are extracted using fuzzy neural networks with forgetting, whose membership functions for qualitative data are represented by enumerated fuzzy sets. We formulate them as switching units in fuzzy neural networks. We tune and prune these functions using back propagation with forgetting and inverse of sigmoid function since the range of the membership functions must be in the unit interval [0, 1]. The proposed network is applied to sample data for estimation of human weight and real data for evaluation of system kitchen.View full abstractDownload PDF (1765K) -
Masaki NAKAI, Manabu KOTANI, Kenzo AKAZAWA1999 Volume 35 Issue 3 Pages 415-421
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe propose a method of feature extraction to improve the performance of pattern recognition technique. The extracted features are defined as polynomial expressions which are composed of the original input information. Polynomial expressions are searched by genetic algorithms. In order to evaluate the effectiveness of the proposed method, we apply the k nearest neighbor classifier to the classification rule. Experiments were performed for the artificial data and the acoustic diagnosis for compressors as the real world task. The results show that the feature extraction with genetic algorithm is effective for these data.View full abstractDownload PDF (1793K) -
Kazuo TANAKA, Tadanari TANIGUCHI1999 Volume 35 Issue 3 Pages 422-427
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper presents new stability conditions and design methods for fuzzy observer-based control. New stability conditions are obtained by relaxing the stability conditions derived in previous works. We present LMI-based designs for fuzzy regulators and fuzzy observers using so-called "parallel distributed compensation" and the relaxed stability conditions. A design example for the ball and beam system shows the utility of the new stability conditions and the proposed design procedures.View full abstractDownload PDF (1382K) -
Hisashi TAMAKI, Michiari OCHI, Mituhiko ARAKI1999 Volume 35 Issue 3 Pages 428-434
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes a method of generating and selecting rules for adjusting the priorities of jobs by using a genetics-based machine learning (GBML) technique, where a state feedback structure is newly introduced. In applying the GBML, we use the Pitts approaches, where the set of rules (rule-set) are represented symbolically as an individual of genetic algorithms, and the fitness of an individual is calculated based on the makespan of the schedule generated by using the rule-set. As for a rule representation, we consider several attributes and status of a job in order to calculate its priority as a weighted sum of these attributes. We actually carried out computational experiments to simple problems with an intree-type precedence relation, which indicate that the method of applying the GBML is effective for finding and selecting good rule-sets.View full abstractDownload PDF (907K) -
Ryota HORIE, Eitaro AIYOSHI1999 Volume 35 Issue 3 Pages 435-443
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper presents dynamic models to search for optimum points by using gradient systems with diffusively coupled many-bodies, and indicates that the dynamic models for quadratic programming problems with variables constrained on the closed interval [0, 1]'s are realized by coupled neural network(N.N.) systems. Concretely, these are external types in which the outputs from neurons are coupled and internal types in which the inner variables of neurons are coupled. Computer simulation for simple problems are carried out to confirm the optimization ability of the proposed coupled N.N. models. In addition, the relation between the proposed internal types and time-dependent Ginzburg-Landau equation is indicated.View full abstractDownload PDF (2186K) -
Hirohisa SAKURAI1999 Volume 35 Issue 3 Pages 444-446
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe triple point of argon is realized calorimetrically using a closed cycle refrigerator (a Gifford-McMahon type refrigerator). The usage of the closed cycle refrigerator with a closed fixed-point cell of argon is found to have a high potential for an easy-handling and the most accurate realizing method, as the temperature distribution inside the cryostat is stable enough for a long period, compared with the conventional cryostat. The standard uncertainty of this system in calibrating standard platinum resistance thermometers at the triple point of natural argon is estimated to be 0.059mK including isotopic uncertainties.View full abstractDownload PDF (1307K) -
Takanori KIYOTA, Eiji KONDO, Nobuhiro OKADA1999 Volume 35 Issue 3 Pages 447-449
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes a design method of the type-1 deadbeat servo system for SISO linear digital systems by using virtual command signal. In this case, the minimum settling time does not change even when integrator is added.View full abstractDownload PDF (329K) -
Yoshihiko MIYASATO1999 Volume 35 Issue 3 Pages 450-452
Published: March 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA design method of adaptive servo controllers for systems with unknown degrees and with uncertain relative degrees r, r+1 or r+2(r∈N), is presented. It is shown that the proposed servo controllers stabilize systems of unknown degrees without exact knowledge of relative degrees, and also estimate unknown internal models of disturbances and reference signals, and that the tracking errors converge to zero asymptotically.View full abstractDownload PDF (360K)
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