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Volume 42, Issue 6
Displaying 1-17 of 17 articles from this issue
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Hiroshi KINJO, Naoki OSHIRO, Koji KURATA, Tetsuhiko YAMAMOTO2006 Volume 42 Issue 6 Pages 581-590
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSOne of the well-known and frequently used crossover operators of the real-coded genetic algorithms (GAs) is the blend crossover (BLX). The BLX utilizes a uniform probability distribution function in the offspring production process. The convergence speed of the BLX is not high and sometimes falls to a local optimum for the searching solution problems. In order to improve the searching performance of the real-coded GA, we propose the use of biased probability distribution functions (BPDF) in the crossover process. The crossover with BPDF frequently produces offspring that are close to the best individuals in the current generation and it is highly likely that these offspring will offerr the best solution to the problem. Furthermore we discuss a mutation that has a constant and extended range that is wider than that of the normal BLX. The mutation is able to conserve the population diversity in the generation field due to its wide range and because it maintains a constant offspring production size range. The crossover with BPDF has the role of faster convergence and the mutation has the role of preventing the trap from falling into the local optimum. Simulations show that the crossover between BPDF and the mutation effectively improves the searching performance of two variable optimization problems and a neural network training problem.View full abstractDownload PDF (1979K) -
1. Spectral StabilityFumihiro SAKUMA, Laina MA2006 Volume 42 Issue 6 Pages 591-596
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESS0.65μm radiation thermometers are used as the standard thermometers at high temperatures. The spectral stability of these thermometers influences largely on the calibration uncertainty. Little information is available about the spectral stability. Therefore, we studied the long-term spectral stability of ten 0.65μm radiation thermometers. Most radiation thermometers had the tendency that the effective wavelengths moved to longer wavelengths in course of time. Some thermometers showed that their effective wavelengths moved at a rate about 0.1 nm/year. Interference filters with hard coating showed very stable effective wavelengths. Three radiation thermometers showed large changes in effective wavelengths and once the effective wavelengths started to move, they did not stop. Thermometers with their effective wavelengths moving more than 0.2 nm/year need to be repaired with the filter. The scale of standard radiation thermometers should be managed on the base of this knowledge.View full abstractDownload PDF (1222K) -
Shinichi YAMAKAWA, Kenji AMAYA, M. PARAMESWARAN (ASH)2006 Volume 42 Issue 6 Pages 597-602
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper introduces a magnetic field measurement technique with nano-resolution using a thin-film magnetic sensor. The method consists of a process, where the thin-film magnetic sensor is scanned over the sample, followed by a processing using a deconvolution scheme. In the scanning process, the thin-film magnetic sensor is scanned over the sample perpendicularly to the sensor. The sample is rotated horizontally under the sensor so that data measurements are obtained at different angles and positions. The deconvolution can be performed using existing methods, which are familiar in computed tomography technology. Numerical simulations were performed to demonstrate the technique's capability of achieving nano-resolution measurements of a magnetic field using the thin-film magnetic sensor. Currently, thin-film magnetic sensors are used as reading heads in hard drive disks (HDD), such as thin-film inductive heads, anisotropic magnetoresistive (AMR) heads, and giant magnetoresistive (GMR) heads. Recently, the film thickness of the GMR head, which is most commonly used as the reading head in HDD, is less than 10nm. Previously, the resolution of the measurement was limited by the width of the sensor (ie. 100nm), however, the new technique has the same resolution as the film thickness (ie. 10nm). The measurement techniques of the HDD industry field can be applied to our measurement method.View full abstractDownload PDF (3075K) -
Kenichiro NONAKA, Hajime NAKAYAMA2006 Volume 42 Issue 6 Pages 603-610
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, a new robust tracking controller for vehicles with active front steering and with side skidding is proposed. Conventional controllers, designed for vehicles without side skidding, assure exponential convergence to the desired trajectory. When applied to vehicles with side skidding, however, these controllers cause a large deviation from the trajectory. We have revised a conventional controller by representing it into time-state control form and by applying an exact linearization technique. Our controller cancels the dynamics of side skidding and successfully achieves exponential convergence to the desired trajectory. The controller assures robustness with respect to uncertainties on cornering forces and external disturbances by a natural extension using sliding mode. The advantages of the proposed controller are shown through simulations.View full abstractDownload PDF (1936K) -
Hiroaki NAKANISHI, Koichi INOUE2006 Volume 42 Issue 6 Pages 611-617
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSUncertainties that exist in a system can be classified as either deterministic or stochastic. In this paper, stochastic uncertainties are focused on because it is the most typical uncertainties in many systems, such as airplane and helicopters and so on. We propose methods to design robust control systems by training a neural network against stochastic uncertainties. Detail characteristic of 3 basic methods are investigated, and moreover some improved methods are also proposed. Numerical simulations of altitude control of an unmanned helicopter, which is disturbed by a wind, demonstrate the effectiveness of proposed methods.View full abstractDownload PDF (2706K) -
Yoshito HIRAI, Yoshio EBIHARA, Tomomichi HAGIWARA2006 Volume 42 Issue 6 Pages 618-627
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we address robust H∞ performance analysis problems of linear time-invariant polytopic-type uncertain systems. We employ polynomially parameter-dependent Lyapunov functions to assess the robust H∞ performance and derive sufficient conditions for the existence of those Lyapunov functions in terms of numerically verifiable finitely many linear matrix inequalities (LMIs). To this end, we first consider to analyze the H∞ performance of uncertainty-free systems by means of Lyapunov functions of a particular form, and explore the existence condition of such Lyapunov functions. We show that, by considering a suitable redundant system description, the existence condition of such Lyapunov functions can be reduced into constrained inequality conditions to which Finsler's Lemma can be applied. It turns that we can readily obtain novel LMI conditions for the H∞ performance analysis of uncertainty-free systems. The LMI-based conditions that enable us to assess the robust H∞ performance of uncertain systems by means of polynomially parameter-dependent Lyapunov functions follow immediately from these newly obtained LMIs. The LMI conditions obtained in this paper can be regarded as a natural extension of those known as extended or dilated LMIs in the literature.View full abstractDownload PDF (1946K) -
Gou NAKURA2006 Volume 42 Issue 6 Pages 628-635
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper we study H∞ tracking problems with preview by state feedback for linear jump systems on the finite time interval. We mainly consider the problem that the reference signals are previewed in a fixed time interval and present feedback control laws for three types of H∞ tracking problems including two other extreme cases. Numerical examples demonstrate that increasing the preview length improves the tracking error. Our theory is an extension of the H∞ tracking theory with preview for linear continuous-time systems to linear jump systems. Our theory can be applied into the control system with the control input realized through a zero-order hold.View full abstractDownload PDF (1904K) -
Hiroshi OKU, Yasuko OGURA, Takao FUJII2006 Volume 42 Issue 6 Pages 636-642
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, a MOESP-type closed-loop subspace model identification method is developed. Although external exciting signals and a priori knowledge of a controller in closed-loop are required, the procedure of the proposed method is very similar to the procedures of the existing MOESP methods. Simulation examples are provided to compare the proposed method with some of the existing methods, that is, CCA10), SSARX5) and PO-MOESP4), and demonstrate that the proposed method is capable of identification not only of an ARMAX model but of a Box-Jenkins model.View full abstractDownload PDF (1393K) -
Takayuki TSUZUKI, Yuh YAMASHITA2006 Volume 42 Issue 6 Pages 643-650
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe purpose of this paper is to solve the global asymptotic stabilization problem for nonlinear systems on general manifolds. It is known that if the state space of a control system is not contractible, the system is not globally asymptotically stabilizable via C1 feedback law, because gradient-like flow on the non-contractible manifold demands multiple singular points. In this paper, we define a control Lyapunov-Morse function having multiple critical points using the concept of the Lyapunov-Morse function, which is a kind of complete Lyapunov functions for dynamical systems with multiple isolated singular points. We derive a discontinuous feedback law from the control Lyapunov-Morse function. Moreover, a condition for global asymptotic stability of the controlled system with the discontinuous feedback law is also obtained.View full abstractDownload PDF (1794K) -
Hiroki SATO, Motoyasu TANAKA, Fumitoshi MATSUNO2006 Volume 42 Issue 6 Pages 651-658
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we derive a dynamic model and a trajectory tracking control law for snake robots, which have passive wheels and active joints. We remove passive wheels of some links, and introduce shape controllable points in the snake robot's body. For a trajectory tracking control of snake robots, it is one of the important problem to avoid the singular configuration like a straight line. Using input-ouput linearization for only the head position of snake robots based on dynamic model, we can control the head position by PD feedback, but the robot will converge to the singular configuration. In order to solve this problem, we propose a control law for shape controllable points, based on an index related to the singular configuration. Using the proposed control law, the robot can accomplish trajectory tracking of the head position without converging to the singular configuration. Simulation results show the effectiveness of the proposed control law.View full abstractDownload PDF (3300K) -
Shuhei KIMURA, Koki MATSUMURA2006 Volume 42 Issue 6 Pages 659-667
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe random number generator is one of the important components of evolutionary algorithms. Therefore, when we try to solve function optimization problems using the evolutionary algorithms, we must carefully choose a good pseudo-random number generator. In the evolutionary algorithms, the pseudo-random number generator is often used for creating uniformly distributed individuals. In this study, as the low-discrepancy sequences allow us to create individuals more uniformly than the random number sequences, we apply the low-discrepancy sequence generator, instead of the pseudo-random number generator, to the evolutionary algorithms. Since it was difficult for some evolutionary algorithms, such as binary-coded genetic algorithms, to utilize the uniformity of the sequences, the low-discrepancy sequence generator was applied to real-coded genetic algorithms. The numerical experiments show that the low-discrepancy sequence generator improves the search performances of the real-coded genetic algorithms.View full abstractDownload PDF (2094K) -
Koichi YOSHIDA, Takeshi TSUJIMURA2006 Volume 42 Issue 6 Pages 668-675
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes an active free space optics (FSO) telecommunication system that enables a mobile terminal to be tracked in user networks of short-range coverage. The central idea is to incorporate a mechanism that controls the transmittal beam direction. This provides the system with a high-speed and ubiquitous optical communication capability over a conventional wireless network with a lower bit rate for control signal transmission. The system configuration including an axis alignment control method is presented. In addition, a prototype of the proposed system is constructed to verify its performance in simulations and fundamental experiments.View full abstractDownload PDF (3182K) -
Osamu FUKUDA, Kiyotaka FUKUMOTO, Hironori SATO2006 Volume 42 Issue 6 Pages 676-682
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe have developed a measuring system to visualize a complete cross-sectional image of human extremities using ultrasonography. Several ultrasound probes measure fragmentary graphical images of one cross-sectional plane, and these images are transformed together. In order to confirm availability of the developed system, we conducted the experiments. It is concluded that the developed system, in many respects, is superior to other imaging devices, because it is portable, safe, and inexpensive. These advantages can be expanded in the field survey. This paper discusses the system structure and the results of the experiments.View full abstractDownload PDF (3848K) -
Tomohiko UTSUKI, Takuya WAKATSUKI, Hidetoshi WAKAMATSU2006 Volume 42 Issue 6 Pages 683-690
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe clinical brain hypothermia treatments by the surface cooling & warming method are experimentally examined using optimal-adaptive and fuzzy control systems on the basis of their common structure of two kinds of subsystems; One is for the realization of physiologically appropriate dynamics using thermal characteristic model and the other is for the compensation of thermal characteristic change of patients.
Both control systems in confirmation of the accurate realization of brain temperature are preciselyy examined under the various experimental conditions using the newly developed water-thermal controlling equipment with resinous mannequin analogous to metabolic and circulatory system of concerning patients.
They ensure the appropriate automatic control of brain temperature with less physiological invasion to patients, as the control deviations of brain temperature, efficiency of heating and cooling with dynamics of water temperature can be kept within the clinically permissible range during its control process. Thus, this structural type of control systems is confirmed useful for the thermal control based on both control algorithms in its clinical application with less influence due to characteristic change and difference of individual patients, which consequently reduces concerning their medical cost, and physical and mental burden of medical staffs.View full abstractDownload PDF (2863K) -
Toru YAMAGUCHI, Masashi UMEDA, Maiji SAITOU, Fumio HARASHIMA2006 Volume 42 Issue 6 Pages 691-697
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSLife became convenient thanks to the information infrastructure that had improved and developed. On the other hand, it is very weak at the disaster such as large earthquakes. Therefore, it is necessary to construct a strong network in the disaster. And also, the function to collect required information, such as an evacuation route and a fire situation, automatically according to a disaster situation is required. This paper proposes two techniques, the technique for conquering the down of the network link at the time of a calamity and the technique of collecting required information automatically according to the situation. This paper builds network intelligence by using these techniques to make the refuge support system at the time of a calamity, and shows the validity of this system by conducting a fire drill experiment.View full abstractDownload PDF (4636K) -
Hiroya YAMAMOTO, Muhammed MAZHARUL ISLAM, Shogo TANAKA2006 Volume 42 Issue 6 Pages 698-700
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes a method of detecting multiple concrete cracks non-destructively using an ultrasonic sensor. Unlike previous methods of detecting only a single crack, our new method can detect multiple numbers of cracks (as well as the bottom) simultaneously. The effectiveness of the method will be verified experimentally.View full abstractDownload PDF (555K) -
Ichijo HODAKA2006 Volume 42 Issue 6 Pages 701-703
Published: June 30, 2006
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe Klimushchev-Krasovskii condition is a sufficient condition for singularly perturbed systems to be asymptotically stable for sufficiently small parameters. This paper concerns whether the condition is also necessary. Descriptions on this issue in some literature are corrected. The corrected result is then proven through the notion of inertia of matrices.View full abstractDownload PDF (433K)
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