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Volume 35, Issue 1
Displaying 1-24 of 24 articles from this issue
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Masayuki OKAMOTO, Shogo TANAKA1999 Volume 35 Issue 1 Pages 1-9
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe fluctuation of an acoustic pressure in a straight pipe is modeled with a linear dynamic system whose state variables are stationary waves of different modes. In our previous report, low order modes of the stationary wave were used to construct an accurate pipe-length on-line measurement system, since high order modes generally disappear faster than lower order ones. But, we found that not only the low order modes but also high order ones are relatively plentifully contained in the fluctuation of the acoustic pressure. These higher order modes have generally a high resolution ability with respect to the pipe-length because of the larger distance between actual and predicted acoustic pressures. This paper presents a criterion to select the optimal modes, using the distance measure “divergence”, to realize a much more accurate pipe length measurement.View full abstractDownload PDF (1834K) -
Reduction of the Phase Error Using PolarizationNaomichi YOKOI, Yoshihisa AIZU, Hiromichi MISHINA1999 Volume 35 Issue 1 Pages 10-16
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSPhase Doppler anemometry (PDA) is useful for sizing small spherical particles. This method is, however, sensitive to phase fluctuation errors caused by the Gaussian beam illumination. This phase fluctuation arises from the interference between reflected light and refracted light from the particle. Thus, we should detect either reflected or refracted light in order to eliminate the errors. This paper studies a reduction of phase errors which is based on the separation of reflected and refracted light by using polarization effect. We numerically investigated the characteristics of phase fluctuations in relation to polarization by using geometrical optics approximation and generalized Lorenz-Mie theory, and estimated the optimum measuring condition. We experimentally confirmed the usefulness of the polarization technique for reducing the phase errors.View full abstractDownload PDF (2414K) -
Takashi EMURA, Masaaki KUMAGAI, Lei WANG, Norio GOKO1999 Volume 35 Issue 1 Pages 17-23
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDynamically walking robots require attitude sensors of high resolution and wide-band frequency response. If these characteristics are not good enough, it is difficult to control the robots stably. Rate gyros are widely used attitude sensors in walking robots, but the rate gyro which has both characteristics of sufficiently high resolution and wide-band frequency response is heavy and expensive. Therefore, the authors tried to get a small, light and low-cost rate gyro which has excellent characteristics both in resolution and response frequency by using multiple sensors and subtraction type of filters.
In this paper, first, a method to expand response frequency of rate gyros without reducing their resolution and an idea of subtraction type of filters which are useful for expanding frequency range are presented. The subtraction type of filter means the filter that has a transfer function obtained by subtracting another transfer function from 1 (unity). This filter provides flat response after composing two signals whose response frequency ranges are different each other. In this case, one is a signal obtained from a rate gyro whose resolution is high enough but response frequency is low, and the other is a signal obtained from a rate gyro whose resolution is low but response frequency is high enough.
If we use an inclinometer together with rate gyros, we can sufficiently decrease zero-drift of gyros, because the inclinometer senses angular displacement by referencing gravity direction and its zero stability is high enough. However, the inclinometer is influenced by horizontal acceleration. This means that we have to use a low-pass filter whose cutoff frequency is extremely low to eliminate signal component induced by horizontal acceleration. Attitude sensor using two rate gyros mentioned above and one inclinometer showed good characteristics concerning zero stability, resolution and response frequency range.View full abstractDownload PDF (1833K) -
Kenbu TERAMOTO, Noriko MORI, Hikaru KAMI-IRISA, Osamu TAKANO1999 Volume 35 Issue 1 Pages 24-31
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes a novel blind target identification algorithm and shows experimental results obtained by a proof-of-concept (POC) model, a 3-D sparse array holographic sonar, which has a limited number of transducers distributed sparsely. The proposed algorithm is based on convex optimization over the direct product of the object space (⊂ RN) and the observed signal space (⊂ RM). By acoustical experiments, it is proved that the proposed algorithm has the following improvements:
(1) Targets can be identified when unknown components exist in the transfer function.
(2) Transient behavior of the convergence becomes more stable than that of POCS algorithm.
(3) Instability caused by the lack of information about the transfer function can be reduced.
(4) Artifacts caused by the spurious lobes can be reduced under the condition that the inter-spacing of tranceducer elements is larger than the wave length.View full abstractDownload PDF (3529K) -
Kazuhiro WATANABE, Shigeaki MATSUBARA, Yuzuru KUBOTA1999 Volume 35 Issue 1 Pages 32-37
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA new type of fiber sensor using OTDR (Optical Time-Domain Reflectometer) has been developed whose concept is intended for structural damage monitoring through fiber networks spread in wide areas to be monitored. The sensor has a spliced hetero-core structure in which a short-length, different core-size fiber is inserted in a single-mode-fiber network line with low transmission loss for the wavelength of 1.3μm. In this study, two types of sensor are demonstrated which are low-insertion-loss and high-sensitivity ones. The variation of the bending losses has been experimentally measured to be 9x10-2, and 3.6dB/deg for the low-insertion loss and the high-sensitivity types, respectively, as a function of rotation angles with which the hetero-core portion is wound. Qualitative discussions are also made both on how these two sensors show high sensitivities to relatively large-radius-bending of the hetero-core portion and on why their characteristics performances are appeared in different fashionsView full abstractDownload PDF (3020K) -
Shogo FUKUSHIMA, Daisuke MORIKAWA, Hidekazu YOSHIKAWA1999 Volume 35 Issue 1 Pages 38-45
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSAccommodation, convergence and pupil constriction, which are called near triad, will usually respond simultaneously at near reflex in natural view condition. It has been reported that accommodation will happen to respond not only to visual distance of a real object but also by psychological factor in relation to perspective, but no research has been made on pupil behavior as another element of near reflex which would be correlated to psychological perspective.
Laboratory experiments were conducted on several subjects, to examine pupillary response by psychological factor to an image with linear perspective on the display, by using Eye-Sensing Head Mounted Display (ES-HMD). The ES-HMD can monitor the user's both eyes and obtain ocular information such as pupil size, eyeblink or eye movement, while presenting visual stimulus to his both eyes.
It was found that for some subjects pupil would respond by psychological factor for the perspective image, which is similar to near reflex of pupil, and its response is correlated with psychological distance given by the image.View full abstractDownload PDF (2444K) -
Akie MUTO, Kenichi HASEGAWA1999 Volume 35 Issue 1 Pages 46-51
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA charge-integrating position-sensitive proportional counter (CIPSPC) has been developed for X-ray image detection. The CIPSPC is a 1-D position-sensitive detector with 320 electrodes, and can be used for industrial X-ray image measurements. With this detector and its signal processor, radiographs can be recorded in the energy range of 8keV X-ray. The detector is 128mm long in effective length, and the signal processor is able to scan 1-line (320ch) for 1ms. Recorded images of 320×250 pixel are obtained with this system. For the purpose of demonstration, the image of free falling scissors was recorded. The measuring time was 100ms for the scissors with the over all length of 150mm. From this image, the binary images of the scissors were obtained. The patterns of fine metal wires were also recorded. It was possible to distinguish the metal wire of 0.3mm in diameter. Experimental results of the image detection demonstrate the feasibility of the proposed CIPSPC system.View full abstractDownload PDF (2463K) -
Satoko YAMAKAWA, Hisao KATO, Norimasa SHINODA, Yasuyuki FUNAHASHI1999 Volume 35 Issue 1 Pages 52-58
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSAs is well-known, an inverted pendulum is one of the typical examples of nonlinear control systems, and, for the stabilization, many controller design methods have been studied. A nonlinear controller was designed by using an approximated model which consists of a series connection of a pendulum and a cart. In the first place, the desired signal of acceleration of the cart is determined for stabilizing the pendulum. Then the control input to cart is determined so that actual acceleration of cart may follow the desired signal. The controller thus designed was shown to expand the range of initial angle from which the system can be stabilized.
In this paper, the generalization of the previous method was investigated based on Potential function. With the proposed method, the range of initial angle from which stabilization is possible is made larger, and, at the same time, the required input amplitude may be made smaller. These points were confirmed by comparative simulations.View full abstractDownload PDF (1610K) -
Kei IMAFUKU, Yuh YAMASHITA, Takahiro SHINBA, Masasuke SHIMA, Hirokazu ...1999 Volume 35 Issue 1 Pages 59-65
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSSufficient conditions of the nonstandard nonlinear H∞ control problem are provided. This problem needs not to satisfy the rank condition of the direct-through matrices from the controlled input to the regulated output and from the disturbance to the measured output. First, we present a feedback law via state feedback. Next, a feedback law via output feedback and an observer gain are given. It is shown by extending the result of the linear system to the nonlinear system.View full abstractDownload PDF (1353K) -
Izumi MASUBUCHI, Etsujiro SHIMEMURA1999 Volume 35 Issue 1 Pages 66-70
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper considers a stability of implicit systems, under which stability every initial-value response of an implicit system does not contain impulses and converges to zero asymptotically. This stability is a generalization of one from the context of descriptor systems, and we applies it to implicit systems that can represent a broader class of systems. We give three necessary and sufficient conditions to this stability: a condition in the Kronecker form, a generalized Lyapunov equation/inequality condition and a certain rank condition of the system pencil. These conditions can be utilized in further research on such as robustness analysis and control systems synthesis based on implicit systems.View full abstractDownload PDF (721K) -
Kenji SUGIMOTO, Masayuki SUZUKI1999 Volume 35 Issue 1 Pages 71-76
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper introduces the notion of γ-positive realness into sampled-data control systems and gives a method for synthesizing such a system. This is achieved by means of the Cayley transform of the closed-loop system, and the well-known lifting technique plays a fundamental role to this end. Phase property of sampled-data systems, together with that of MIMO continuous-time systems, is discussed in relation to the γ-positive realness. An example is given to illustrate the result.View full abstractDownload PDF (1151K) -
Akira KOJIMA, Shintaro ISHIJIMA1999 Volume 35 Issue 1 Pages 77-84
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSPerformance of preview control is investigated in terms of H∞ criterion. In the infinite-horizon time setting, we define a preview full-information (FI) problem and clarify the solvability and analytic solution in the framework of finite-dimensional operations. The necessary and sufficient condition of the solvability is characterized with the stabilizing solution to matrix Riccati equation. The control law is constructively given based on the matrix Riccati equation with finite-dimensional operation. The preview FI problem covers essential part of H∞ preview problems and enables to obtain analytic solutions for general problems.View full abstractDownload PDF (1380K) -
Zi-Jiang YANG, Michitaka TATEISHI1999 Volume 35 Issue 1 Pages 85-90
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes a robust nonlinear controller for position tracking problem of a magnetic levitation system, which is governed by an SISO second-order nonlinear differential equation. The controller is designed in a backstepping manner, based on the nonlinear system model in the presence of parameter uncertainties. The effects of the parameter uncertainties are reduced by a nonlinear damping term and the offset position error is removed by a PI controller. Input-to-state stability of the control system is analyzed and experimental results are included to show the excellent position tracking performance of the designed control system.View full abstractDownload PDF (1826K) -
Tetsuji TANI, Takahiro KOBAYASHI, Sadaaki MIYAMOTO1999 Volume 35 Issue 1 Pages 91-96
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper presents a practical control system that is designed based on human's experience and control know-how, and plays the role of supervisors of conventional PID controllers. Each supervisory controller consists of two control blocks, estimation block and compensation block. We use a statistical model using multi-regression analysis for the estimation block to estimate parameters of plant operation, and fuzzy logic for the compensation block to correct operating condition. The supervisor and PID control systems have been applied to hydrogen purity control in a large scale petroleum refining plant. The systems have shown good performances and therefore have advantages of (1) reducing operator's interaction, (2) reducing energy consumption, and (3) reducing CO2 generation.View full abstractDownload PDF (911K) -
Qiang HUANG, Kazuo TANIE, Shigeki SUGANO1999 Volume 35 Issue 1 Pages 97-104
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn order for a mobile manipulator to be used in areas such as offices and houses, the mobile platform must be small-sized. In the case of a small-sized platform, the mobile manipulator may fall down when moving at high speed, or executing tasks in the presence of disturbances. Therefore, it is necessary to consider both stabilization and manipulation simultaneously while coordinating vehicle motion and manipulator motion. In this paper, we propose a method for coordinating vehicle motion planning including manipulator configuration, and manipulator motion planning including platform stability. Specifically, first, the optimal problem of vehicle motion is formulated, taking into account vehicle dynamics, manipulator workspace and system stability. Next, the manipulator motion is derived, considering stability compensation and manipulator configuration. Finally, the effectiveness of this method is demonstrated by simulation examples.View full abstractDownload PDF (2304K) -
Guoguang ZHANG, Junji FURUSHO1999 Volume 35 Issue 1 Pages 105-112
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe servo control system driving a load through a flexible shaft or transmission system is widely used in industrial applications. Our purpose is to develop systematic analysis and design methods for two-inertia system. A conventional PI speed control system with a torsional load is redesigned, and the damping characteristic of the system is derived for a variety of inertia ratios. It is shown that the dynamic characteristic of the system strongly depends on the inertia ratio of load to motor. Three kinds of typical pole assignments with identical radius/damping coefficient/real-part are analyzed and compared, and the merits of each pole assignment design are concluded. Furthermore for small inertia ratio, we present how to improve the damping by introducing a feedforward filter or a derivative feedback.View full abstractDownload PDF (1634K) -
Kazuya ASANO, Kazuhiro YAMAMOTO, Yasuo ICHII, Nobuaki NOMURA1999 Volume 35 Issue 1 Pages 113-121
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper presents a new control method for interstand tension and looper height in the hot strip finishing mill. In the finishing mill, several passes of rolling are executed by tandem rolling in the presense of interstand tension. Tension can be adjusted either by manipulating roll speed or by using the looper, which is implemented between stands. Since tension and looper height control is the key to successful mill operations, several multivariable control schemes have been applied to cope with interactions between tension and the looper. However, they lead to complicated controllers which are hard to be tuned on site. The proposed method is based on decentralization and coordination. First, the iteractions are evaluated using the structured singular value to ensure the applicability of decentralized control. Then, a decentralized controller based on the two-degree-of-freedom IMC (Internal Model Control) sturucture is applied. Moreover, impedance control of the looper is introduced to retrieve the coordinated action of the looper and to improve transitional responses of tension. The control scheme enables stepwise commissioning of control systems, which is very helpful for on-line tuning. The control scheme has been successfully applied to the tension and looper control system in a hot strip mill.View full abstractDownload PDF (1471K) -
Masatoshi NAKAMURA, Shigeto AOKI, Satoru GOTO, Nobuhiro KYURA1999 Volume 35 Issue 1 Pages 122-129
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSPerformance at high speed with high accuracy is required for contour control of industrial robot arms. Torque saturation exsiting in the industrial robot arms often causes deterioration of contour control performance. In this research, the following items of the contour control performance of industrial articulated robot arms under torque constraints is considered; 1. derivation of a relationship among the torque, accuracy of the trajectories and operation speed, 2. clarification of the upper limit of the contour control performances of industrial articulated robot arms, 3. proposal of the contour control method which enables the best contour control performance under the torque constraints. The effectiveness of the proposed contour control method was assured by experimental results of an actual industrial robot arm.View full abstractDownload PDF (1934K) -
Shigeto NISHIDA, Masatoshi NAKAMURA, Hiroshi SHIBASAKI1999 Volume 35 Issue 1 Pages 130-137
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIf evoked potentials with varying peak latency are averaged time-locked to stimulus, the averaged waveform is deteriorated due to the asynchronous averaging to each peak of evoked potential. In this study, deterioration characteristics of the waveform of asynchronous averaging were theoretically analyzed based on an assumption that a peak latency of the evoked potential varied according to a Gaussian distribution. By using the derived equation for the characteristics, a method for reconstructing the original waveform of evoked potential from the asynchronous averaged waveform was proposed. Furthermore, we derived a standard deviation of the estimation for the reconstructed waveform and obtained an interval estimate of the original waveform. After an evaluation for the proposed methods by using simulation data for evoked potential, we applied the method to actual data for event-related potential of P300 and obtained satisfactory results.View full abstractDownload PDF (1500K) -
Noriyasu HONMA, Masao SAKAI, Kenichi ABE, Hiroshi TAKEDA1999 Volume 35 Issue 1 Pages 138-143
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe paper demonstrates that a complexity of dynamics in recurrent networks with N neurons can be controlled by our gradient methods. The complexity, i.e. the Lyapunov exponent, is calculated by observing the state transition for a long-term period T. One of the control methods is based on the conventional learning algorithms for the recurrent networks. This is the method with high-precision, but it requires O(N5T) expected time. To reduce the expensive run time, we propose another method based on the approximate relation between the complexity and a new parameter of the network configuration reported in our previous papers. This approximation requires only O(N2) run time. Simulation results show that the first method can control the exponent and that the approximation one can control the exponent under a restriction. The networks can learn not only the target time series, but also the exponent of the target by a combination method which is incorporated the proposed control method into the conventional learning algorithm.View full abstractDownload PDF (1403K) -
Hirohisa SAKURAI1999 Volume 35 Issue 1 Pages 144-146
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe triple point of neon is realized calorimetrically using a closed cycle refrigerator (a Gifford-McMahon type refrigerator). The usage of the closed cycle refrigerator combined with a closed fixed-point cell is found not only to be the easiest and the simplest way to realize the fixed points in both handling and operation compared with the traditional cryogenic technique using liquid helium, but to have a potential to be one of the most accurate realizing methods. The standard uncertainty of this system in calibrating standard platinum resistance thermometers at the triple point of natural neon is estimated to be 0.056mK. The highly stable low temperature environment of the refrigerator revealed that natural neon has long relaxation time constants for the isotopic spatial equilibration after pulse heating.View full abstractDownload PDF (2039K) -
Kazumichi OKAJIMA, Kang-Zhi LIU, Toshimichi MINOWA1999 Volume 35 Issue 1 Pages 147-149
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn recent years, various electronic control devices have been used in order to improve the performance of cars. One purpose is to make the driving comfortable. In automatic transmission cars, torque fluctuation occurs due to gear shifting, this worsens the drivability. In this research, we try to reduce the fluctuation of output torque of transmission via feedback control. H∞ control theory is used in the design of control system. The effectiveness of the designed control system is verified by experiment.View full abstractDownload PDF (356K) -
Shigeki HIROBAYASHI, Masakazu YAMAZAKI, Haruhiko KIMURA, Takashi OYABU1999 Volume 35 Issue 1 Pages 150-152
Published: January 31, 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIdentification of human activity is important in space control. A model of indoor space was created using a linear system. By applying a combustible gas sensor to this model, we analyzed changes in the indoor environment. The results of this analysis indicate that: (1) the gas diffusion coefficients specific to a given indoor space can be estimated from the response signals of the gas sensor; (2) space transfer characteristics can be described using the gas diffusion coefficient alone; and (3) inverse filtration of the thus estimated space transfer characteristics allows us to extract drive signals from the entire output signals of the sensor. In an experiment in which the indoor environmental changes during daily life were measured, drive signals proportional to the amounts of human activity were obtained. These results suggest that the detection of human actions in an indoor space using a combustible gas sensor can be improved by eliminating the residual components from the entire signal output.View full abstractDownload PDF (509K) -
1999 Volume 35 Issue 1 Pages e1
Published: 1999
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDownload PDF (113K)
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