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Volume 23, Issue 8
Displaying 1-20 of 20 articles from this issue
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Yasutaka TAMURA, Hiro YAMASAKI1987 Volume 23 Issue 8 Pages 781-787
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper is presented on a new technique for “Holographic Doppler Velocimetry”. In this technique, uncorrelated Linear Period Modulated (LPM) pulses are transmitted, and velocity vectors are calculated from the digitized echo waveforms detected by receiver array.
Using LPM pulses, information on positions and velocities of multiple objects is obtained with a single transmitting and receiving process, then high speed data acquisition is capable. Velocity estimating algorithm is simplified since Doppler shift is detected as phase rotation of echo.
In the paper, the principle of the velocimetry is described for the system which has multiple transmitters and 1-Dimensional receiver array. Velocity estimating algorithm based on matching operation is presented.
The accuracy and spatial characteristics of the velocimetry is evaluated as functions of transmitted pulse's parameters (Chirp rate, frequency band width), array size, and signal to noise ratio.
The experimental results using airborne ultrasound and computer simulation show the ability of the method for 2-D velocimetry.View full abstractDownload PDF (872K) -
Eisuke TOHJIMA, Takuso SATO1987 Volume 23 Issue 8 Pages 788-793
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn the previous paper a new method for the measurement of the distribution of the flow velocity has been proposed. It uses the nonlinear effect of ultrasonics in gas medium and the distribution can be derived only from the data observed at two ends of the observing line without any seeds. In this paper some trials to increase the accuracy of the system are presented. First, a method for the calibration of the amplitude of the observed flow velocity is shown, then a method for the generation of the desired optimum pumping wave is proposed. The elimination of the scalar fluctuation due to the temperature change is realized by combining the data obtained through exchanging the pumping and probing positions. The change of the waveform of the pumping is also compensated by dividing the observing region and using corresponding waveforms for deconvolution. The experimental results show the effectiveness of these proposed methods.View full abstractDownload PDF (731K) -
Ippei TORIGOE1987 Volume 23 Issue 8 Pages 794-799
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSAcceleration of inviscous flow through a straight pipe varies in proportion to the axial pressure gradient. Two pressure taps spaced a small distance apart along the flow direction are made on a pipe. The pressure difference between these taps, which is a finite difference approximation for the axial pressure gradient, is picked up by a manometer of high sensitivity. The output of the manometer is proportional to the acceleration of the flow through the pipe. A trial device was built which utilized two condenser microphones for picking up the pressure difference. The new mehtod has been verified by experiments with this device.
A new flowmeter is proposed for measuring pulsating flow. The new flowmeter consists of a conventional differential pressure flowmeter and a device based on the method described above. The device is employed for estimating the acceleration term in the output of the differential pressure flowmeter under pulsating conditions. The estimated acceleration term being subtracted, the acceleration error in the measurement of pulsating flow can be eliminated. An experimental apparatus which employed a venturi meter as a differential pressure flowmeter was built on a trial basis. Several measurements for air flow have been performed with this apparatus. The results indicate that the proposed flowmeter is capable of measuring directly the instantaneous rate of pulsating flow.View full abstractDownload PDF (1263K) -
Tadashi ITO, Sadao FUJIMURA1987 Volume 23 Issue 8 Pages 800-805
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe consider a pixel in an image like a pixel in a remotely sensed image, corresponding to an area AF on the ground, in which there are several materials belonging to different categories. It is possible for us to determine the area covered by each material if we know the n-component (multi-spectral) measurement vector x representing the pixel and the n-component vectors xi representing each material included in the pixel. Here we assume that the vector x is a linear combination, that is, the weighted sum, of the vectors xi; x=Σaixi, where Σai=1. The weight ai is the proportion of the area covered by a material i in the whole area AF. To estimate ai is to solve for ai an equation system by x=Σaixi (i=1, 2, 3, …) when x and xi are given.
The vector xi representing each category is determined by training data selected from the image data to be processed. The vector xi does not necessarily represent the category to which the training data belong. In the present paper, we make a model for the difference between the true representative vector xi and the vector xi estimated from the training data taking the account of the variation of the diffuse reflectance of the terrain due to change in look angle.
The method proposed up to now is formulated as an algorithm using restricted least squares method. It is analytically shown to be highly probable that the method gives us very erroneous results owing to the difference. The computer simulation shows that it is the case for possible situations.
A new method for pixel decomposition is also proposed. The method uses least squares algorithm based on the application of the algorithm directly to the area instead of to the multi-spectral measurement vector as the conventional method does. The accuracy is theoretically shown to be significantly improved, and is also confirmed by computer simulation.View full abstractDownload PDF (711K) -
Hiroshi HARADA, Hiroshi KASHIWAGI1987 Volume 23 Issue 8 Pages 806-811
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes a new method of random number generation using a high-order M-sequence. This method uses Tausworthe's method for initializing seed matrix and uses Lewis & Payne's method for generation random numbers. Therefore, generated numbers are uniformly distributed in a high dimensional space and generation time becomes shorter.
When we use a high-order M-sequence for generating random numbers, selection of an initial n-tuple for generating M-sequence is important. If an unsuitable n-tuple is used, generated numbers are not random for a while. In order to solve this problem, in case of this method, initial n-tuples are chosen under the consideration of the partial properties of M-sequence.
Several statistical tests are applied to the random numbers generated by this method and it is shown that the numbers have good random properties.View full abstractDownload PDF (744K) -
Hiroshi KASHIWAGI, Teruo KOHASHI, Hiroshi HARADA1987 Volume 23 Issue 8 Pages 812-815
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe statistical properties of M-sequence over its period are well known, whereas the properties of M-sequence over a part of the period are not yet known. This paper proposes two concepts for evaluating the partial random properties of M-sequence. One is the entropy per one tuple, and the other is the randomness which is defined as a weighted average of the entropy. These concepts are calculated at several phases (including cyclotomic phases of the characteristic M-sequence) of 129 degree M-sequence. The results shows that these concepts are useful for evaluating the partial random properties of M-sequence.View full abstractDownload PDF (505K) -
Hiroshi HARADA, Hiroshi KASHIWAGI1987 Volume 23 Issue 8 Pages 816-820
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes a new concept “resemblance” for evaluating the partial resemblance between any two phases of an M-sequence. By use of this concept, we can evaluate the resemblance quantitatively.
The authors first show that the partial properties of M-sequence are influenced by runs of 0's or 1's in the initial n-tuple of M-sequence. Then a new concept called resemblance is proposed for evaluating the resemblance between any two n-tuples. The resembalnce between the initial n-tuple at phase 0 and the n-tuple at several phases is calculated. The results show that the new concept “resemblance” is very effective for evaluting the resemblance between the partial properties of M-sequence.View full abstractDownload PDF (609K) -
Takeshi OHSHIMA, Takayoshi NAKAMIZO1987 Volume 23 Issue 8 Pages 821-827
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper deals with the bearings-only target tracking problem. This estimation problem is not amenable to simple solution. First, an intrinsic system nonlinearity precludes the rigorous application of conventional linear analysis. Secondly, since only bearing measurements can be obtained, some of the states are not observable prior to an observer's maneuver. Thirdly, the performance of any bearings-only estimation technique is affected by the geometric characteristics and the relative motion of target and observer. When the extended Kalman filter is applied to this problem, it exhibits unstable behavior and often leads to solution divergence. To circumvent these difficulties, a Pseudo-Linear Filter (PLF) has been proposed. The PLF is simple to implement and provides stable and good estimates as long as the target velocity is constant. However, the PLF cannot track a maneuvering target. So, in this paper, an adaptive tracking filter which can track a maneuvering target is constructed by combining the PLF with the detection and estimation of abrupt changes. To examine the performance of the adaptive tracking filter, various target-observer geometry are simulated and the algorithm is implemented. A suboptimal control of the observer's maneuver to improve the estimation performance is also presented together with simulation results.View full abstractDownload PDF (938K) -
An Approach of Model Following ControlKen ITO, Takeshi FUJISHIRO, Taketoshi KAWABE, Kimio KANAI, Yoshimasa O ...1987 Volume 23 Issue 8 Pages 828-834
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe propose a design method of feedforward type motion control system that provides desired response of yaw rate and lateral acceleration for a four wheel steering vehicle (4 WS).
This paper firstly presents three design methods of yaw rate, lateral acceleration and D* (which is defined as a linear combination of yaw rate and lateral acceleration) control system respectively. These systems are synthesized by model matching control or model following control.
In order to verify the effectiveness of the proposed method, the computer simulation of vehicle motion was carried out, resulting in good agreement between a reference model and a controlled vehicle. Futhermore, driving tests were conducted with an experimental vehicle having electronically controlled rear wheel steering mechanism. In step response test to steering wheel input and lane change test, the responses of the controlled vehicle matched with the model satisfactorily, and in free response test at the vehicle speed of above 100km/h, the settling time of the controlled vehicle was reduced by more than 50%.
From these results, it has been confirmed that the proposed design method of rear wheel angle control system is useful in improving maneuverability and stability of the vehicle.View full abstractDownload PDF (787K) -
Kimio KANAI, Shigeru UCHIKADO, Takeshi FUJISHIRO, Ken ITO, Taketosi KA ...1987 Volume 23 Issue 8 Pages 835-841
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper we propose a design method of adaptive yaw rate control system of a new-type automobile car having electronically controlled rear wheel steering mechanism.
First, the spectrum density of steering wheel angle and yaw rate was measured on popular roads and cut-off frequency of the control filter could be determined between 1 to 3Hz. Next, parameters of the car model were identified by the hybrid-type adaptive method using measured data of vehicle velocity, steering wheel angle and yaw rate. The results were shown to be acceptable based upon the comparison between time responses, where the measured data of steering wheel angle is used as input, and the Bode diagrams of nominal and estimated systems.
The desirable output response of the closed-loop system was obtained by a simulation using control parameters, which were used to the nominal system, calculated from the identified ones. The results indicate that the proposed method is useful to design actual control systems of a car.View full abstractDownload PDF (824K) -
Tsutomu HASEGAWA, Hajime TERASAKI1987 Volume 23 Issue 8 Pages 842-848
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSAn efficient method that finds collision-free paths for a manipulator with 6 revolute joints is described. The method first describes a global structure of the free space in the 3-D joint space of the arm. Both the collision-free space of the arm and a large open space in the workspace defined as a space where any orientation of the hand is possible are represented in this description.
Given the initial position and orientation of the hand, a path is searched for to the nearby open space as follows. A local space is described in the real 3-D workspace around the hand at the initial position. Then the description is analyzed, and candidates of the intermediate goal specifying the hand position and orientation are generated. The candidates of the intermediate goal are checked one by one until a path is found from the initial point to the intermediate goal and from the intermediate goal to the nearby open space.
The path planning system has been implemented for the ETA-2 (ETL's Torque Controlled Arm v. 2). The system has successfully planned paths in tightly cluttered workspaces.View full abstractDownload PDF (1092K) -
An Approach Using the Hierarchical Structure Stochastic AutomatonNorio BABA1987 Volume 23 Issue 8 Pages 849-855
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper is concemed with an intelligent behavior of mobile robots going through a maze having numbers of gates that close with unknown rejecting probabilities.
After the brief introduction concerning leaming behaviors of the hierarchical structure stochastic automata, the absolutely expedient leaming algorithm under the nonstationary multiteacher environment is proposed. It is shown that the hierarchical structure stochastic automata with this algorithm can be successfully applied in order to let mobile robots gradually find the best way in the maze.View full abstractDownload PDF (898K) -
Shigeru ANDO1987 Volume 23 Issue 8 Pages 856-858
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDownload PDF (442K) -
Yasumitsu KURANO, Hiroshi KOBAYASHI, Kiyoshi YOSHIDA1987 Volume 23 Issue 8 Pages 859-861
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDownload PDF (425K) -
Fumihiro SAKUMA, Akira ONO, Susumu HATTORI1987 Volume 23 Issue 8 Pages 862-863
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDownload PDF (274K) -
Shin-ichi MIYAMOTO, Seiichi SHIN, Shigenori OKUBO1987 Volume 23 Issue 8 Pages 864-866
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDownload PDF (322K) -
Seiichi SHIN, Toshiyuki KITAMORI1987 Volume 23 Issue 8 Pages 867-869
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDownload PDF (359K) -
Toshiharu KAGAWA, Masashi SHIMIZU, Yajiro MORITA1987 Volume 23 Issue 8 Pages 870-872
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDownload PDF (274K) -
Naoyuki TAMARU1987 Volume 23 Issue 8 Pages 873-875
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDownload PDF (319K) -
Applications of Time Petri NetsNobumichi ISHIDO, Atsushi FUJIMORI, Tomiji HISAMURA1987 Volume 23 Issue 8 Pages 876-878
Published: August 30, 1987
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper points out the possibilities of occurences of “set passing phenomena” in suboptimal (non-delayed) schedulings of jobshop type repetitive processes, obtained by applying a time Petri net with the natural firing rule. The preventing conditions for the phenomena are investigated by the Petri net approach.View full abstractDownload PDF (343K)
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