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Volume 33, Issue 3
Displaying 1-12 of 12 articles from this issue
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Kenji KAWASHIMA, Toshinori FUJITA, Toshiharu KAGAWA1997 Volume 33 Issue 3 Pages 149-154
Published: March 31, 1997
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIt is difficult to measure the flow rate of compressible fluids, because the volume of compressible fluids changes with temperature. Therefore, there is no easy and effective method on the unsteady flow rate measurement of compressible fluids. We have proposed a simple method to measure instantaneous flow rates of air using an isothermal chamber. In this paper, a simple method to measure the unsteady oscillating flow rate of air using the chamber is proposed. The isothermal chamber can almost realize isothermal condition due to larger heat transfer area by stuffing steel wool in it. Therefore, the flow rate of air discharged from the chamber is obtained only by measuring pressure in the chamber. The unsteady oscillating flow rate is generated by a servo valve installed on the chamber. At first, the measurement error of the method is examined. Then, the unsteady oscillating flow rate was measured by the proposed method against several frequencies. It became clear from the experiment that the proposed method can measure the unsteady oscillating flow rate upto 40[Hz] within 7% of errors.View full abstractDownload PDF (1231K) -
Yuji YAMADA, Shinji HARA, Hisaya FUJIOKA1997 Volume 33 Issue 3 Pages 155-162
Published: March 31, 1997
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper considers the H∞ control problem with constant diagonal scaling related to the robust control synthesis for systems with structured time-varying uncertainties. It has not been found that the general output feedback problem can be reduced to a convex optimization problem, and hence only a locally optimal solution can be obtained instead of the global one. The purpose of this paper is to provide an algorithm to find a suboptimal solution with any specified small tolerance or a globally optimal solution for the constantly scaled H∞ control problem. We introduce notions of ∈-feasibility and ∈-feasibility test algorithm in order to develop desired algorithms. It is shown that we can get an algorithm to find a sub-optimal solution within tolerance ∈>0 by combining the bisection method, if we have an ∈-feasibility test algorithm. The ∈-feasibility test algorithm named rectangle covering method is proposed. We also show that the worst case computational complexity is of polynomial order in the inverse of tolerance and the size of a priori given interval of scaling.View full abstractDownload PDF (1849K) -
Kenji FUJIMOTO, Toshiharu SUGIE1997 Volume 33 Issue 3 Pages 163-168
Published: March 31, 1997
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper is concerned with the stability of exact linearization in the presence of input disturbances. We derive a necessary and sufficient condition for a class of nonlinear systems to be asymptotically stabilizable against step disturbances by exact linearization. This result shows that stability of the linearized systems strongly depends on the choice of coordinates transformation when there exist input step disturbances. An illustrative numerical example is given.View full abstractDownload PDF (1453K) -
ShinIchi AIHARA, Teruo KABEUCHI1997 Volume 33 Issue 3 Pages 169-176
Published: March 31, 1997
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe study a mathematical model of a micro-tunneling machine which is used for the conduit instollation for communication cables. By using this tunneling machine, a flexible pilot pipe is thrusted into a ground and hence the total length of the inserted pipe becomes a function of time. Furthermore, the thrust force generated by a hydraulic jack is stochastically perturbed. The transverse displacement of the inserted pipe is firstly shown to be governed by a hyperbolic equation with free boundary by using the Hamilton principle. Secondly, two digital simulation examples are demonstrated for checking the buckling phenomena to the inserted pipe.View full abstractDownload PDF (1829K) -
Noriyuki TANAKA, Kazuo YAMANAKA, Naoya KAWASAKI1997 Volume 33 Issue 3 Pages 177-181
Published: March 31, 1997
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper is concerned with a pole assignment problem for linear time-invariant systems with incomplete state observation. We considered the “certainty-equivalence” scheme based on a full-order observer. Multiple time-delays are intentionally applied to eliminate the error in the state reconstruction. The closed-loop system eventually has the form of Youla-parametrization, in which the state-feedback gain is selected so that the closedloop poles are assigned at designated points. The proposed method enables the state of the plant to behave as if it is controlled by state feedback. The closed-loop system makes an infinite dimensional system with a finite number of poles. A simple example is presented to illustrate our idea. Computer simulation on the example suggests robustness of the proposed scheme against a small perturbation in the plant parameters.View full abstractDownload PDF (1028K) -
Masafumi OKADA, Hiroaki FUKUSHIMA, Toshiharu SUGIE1997 Volume 33 Issue 3 Pages 182-188
Published: March 31, 1997
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we propose a new subspace state-space system identification method using not only the input-output data of the system but also the nominal model data. This method can find a good approximation of the systems in the presence of noises based on the identification cost function. Also, it is applicable to closed-loop identification. Furthermore, the effectiveness of this method is shown by numerical examples.View full abstractDownload PDF (1443K) -
Yuh YAMASHITA, Masasuke SHIMA1997 Volume 33 Issue 3 Pages 189-194
Published: March 31, 1997
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, a new numerical computation method using genetic algorithm for an optimal control problem with terminal constraints and singular arcs is proposed. The input functions are parameterized using spline interpolation, which has devices that can represent discontinuous input functions. In order to treat the terminal constraints properly, Lagrange multipliers that are contained in genetic information of chromosomes are introduced. On the singular arcs, coefficients of inputs in Hamiltonian vanish, so the coefficients on the arcs are included in the extended performance index. The weight constants of the extended performance index are changed adaptively at every generation of the genetic algorithm. A simple example is solved using this method, which verifies the efficiency of genetic algorithm in the computation of the optimal control.View full abstractDownload PDF (1207K) -
Weimin PAN, Toshinori FUJITA, Masaya SHIMIZU, Toshiharu KAGAWA, Hideo ...1997 Volume 33 Issue 3 Pages 195-202
Published: March 31, 1997
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper describes modeling and characteristic analysis of a pilot operated gas pressure regulator which is generally applied in high pressure main pipelines of a city gas distribution system. The gas regulator is designed to be a perfectly non-bleed and self driven device which uses the upper stream gas pressure as the driving power source and is composed of a primary pressure regulator, a pilot valve and a main valve. A mathematical model of the gas pressure regulator is presented in the paper. Linearizing characteristics of the pilot valve using the input-output gain and output flow rate gain, a block diagram of a gas regulator is presented in the paper for analyzing system behavior. Effects of the supply pressure regulator which drives the pilot valve in the pressure of the secondary pressure plus a fixed bias pressure are analyzed. It is made clear that with the supply pressure regulator, characteristic variation to operating condition of the gas pressure regulator is sharply restrained. Relations among system characteristics, regulator element parameters and the operating condition are analyzed in the paper. The model is verified by experiments. Simulation results based on the mathematical model show good agreement with experimental results.View full abstractDownload PDF (2027K) -
Takafumi OISHI, Kazuo FURUTA, Shunsuke KONDO1997 Volume 33 Issue 3 Pages 203-208
Published: March 31, 1997
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper is to propose a new architecture of a self-creating and organizing neural network for workspace recognition and navigation of an autonomous mobile robot. The robot assumed in this study learns its workspace with sonar sensors but without dead reckoning. The network proposed is organized into a graph structure rather than a tree with forgetting old links so that few dead nodes and dead links are created; the space of input signal can be covered efficiently by unsupervised learning. Methods of path planning and navigation based on a topological map created by learning has been proposed as well. The proposed architecture was tested by simulation of an autonomous mobile robot with eight sonar sensors, and it was demonstrated that the architecture is useful for the purpose.View full abstractDownload PDF (1489K) -
Masafumi IWATA, Shirou HIKITA, Kiyotoshi KOMAYA1997 Volume 33 Issue 3 Pages 209-215
Published: March 31, 1997
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSTraffic control systems, like elevator group control systems, have the aim of improving their performance within limits of their resources, and they have to take specific control actions under particular traffic conditions. The origin-destination (OD) matrix is usually employed to represent traffic flows. While we have practical means to measure traffic counts, we cannot obtain the OD matrix directly from accumulated counts. Therefore, conventional elevator group control systems detect typical traffic patterns instead of estimating the OD matrix.
In this paper, we have proposed a detection system of typical elevator traffic patterns with neural networks. Inputs of the system are traffic counts, and outputs are feature modes of traffic. The advantage of our system is easy to apply any buildings without specific adjustments. Furthermore our system has robustness for stochastic fluctuations of input data. We have made some simulations and experiments using real traffic counts, and their results show the successful performance of learning and detecting elevator traffic patterns.View full abstractDownload PDF (3100K) -
Zi-Jiang YANG1997 Volume 33 Issue 3 Pages 216-223
Published: March 31, 1997
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes a new and computationally efficient approach to hidden-layer size reducing for multilayer neural networks. The author's attention is focused on minimizing hidden-layer redundancy using the orthogonal least-squares (OLS) method with the aid of Gram-Schmidt orthogonal transformation. The neural network with a large hidden-layer size is first trained via a standard training rule. Then the OLS method is introduced to identify and eliminate redundant neurons such that a simpler neural network is obtained. The OLS method is employed as a forward regression procedure to select a suitable set of neurons from a large set of preliminarily trained hidden neurons, such that the input to the output-layer is reconstructed with less hidden neurons. At each step of regression, the increment to the energy of the summation of the weighted outputs of the hidden neurons (the input to the output-layer) is maximized. And the weights of the links between the selected hidden neurons and the output layer is automatically determined through the regression procedure. Therefore the neurons which contribute trivially to the input to the output-layer can be eliminated without much distortion of the neural network output. Simulation results are included to show the efficiency of the proposed method.View full abstractDownload PDF (1771K) -
Yasuchika MORI, Kanta KATO, Kenko UCHIDA1997 Volume 33 Issue 3 Pages 224-226
Published: March 31, 1997
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe propose an autonomous vision system architecture, which consists of a reactive control scheme and an active vision scheme, for automatically building maps of unknown environments. The validity of this architecture is demonstrated through a hardware model experiment.View full abstractDownload PDF (982K)
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