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Volume 39, Issue 11
Displaying 1-12 of 12 articles from this issue
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Kimio SASAKI, Mariko IKEDA2003 Volume 39 Issue 11 Pages 985-992
Published: 2003
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSPolarity cross-correlation is a simplified version of the usual correlation such that one signal is polarized to its signs in preceding to the correlation opration, and the required multiplication can be replaced by simple signdiscrimination and addition or subtraction. Thus, it may have the possibility of real time processing without any reduction of precision. However, no application to deterministic signals is seen. First, this paper explores its applicability to such signals as generally as possible, by theoretically or numerically examining polarity and usual auto-correlation functions of four kinds of the typical signals. As a result, it is made clear that both methods provide the equivlent characteristics for sinusoidal and FM-signals. Then, based on the results, its two applications, i.e., detection and demodulation of FSK signals in digital communication and time delay estimation in ultrasonic A-mode measurement, are proposed. The effectiveness of the proposed applications is confirmed through consideration about its superior implementation feature as well as such numerical results that both correlation methods work well equivalently up to a certain received SNR separate for each of the applications.View full abstractDownload PDF (2175K) -
Hiroki YAMAMOTO, Nobuharu AOSHIMA2003 Volume 39 Issue 11 Pages 993-1001
Published: 2003
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we propose evaluation indices for grasping the characteristics of measurement signals from three axis sensors. Those evaluation indices are based on signal representation of quaternion and spectral analysis on the form. And, those are led by linking the coefficients of such spectra and the concept of the periodic motion on elliptic orbit in quaternion space. To show the benefit of the method in future use, an model experiment processing the three axis acceleration measurement data, which were recorded by originally developed sensor ball, were carried out. Then, the indices were calculated with the acceleration data given in such manner. As the result, comparing to the complex spectra at each axis, our evaluation indices have some advantages at the point of quick observation and recognition of three dimensional dynamical characteristics. Although the data processing based on quaternion has been widely used among the field of computer graphics or attitude control system of artificial satellite, a few attention are paid to the application for the signal processing of three dimensional measurement signal. On the other hand, in the field of the diagnostics with vibration such as of rotating machine, the spectral analysis which can observe a phase relation between multiple axis may become to be in great demand. So that, our evaluation indices will be a useful mean under such situation.View full abstractDownload PDF (2290K) -
Yoshikazu SATO2003 Volume 39 Issue 11 Pages 1002-1009
Published: 2003
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSFractal dimension can be used to describe the self-similarity, the complexity, or the irregularity of images. One of the most popular ways to estimate the fractal dimension of images is the box-counting method (BCM). Its naive estimates, however, tend to be inaccurate. This paper gives careful consideration to the sources of inaccurate estimates and modifies Buczkowski's method for accurate estimation of the fractal dimension of binary images. Buczkowski's method is the modified version of the BCM and can provide the most accurate estimates of all the methods based on the BCM so far. The proposed method automatically eliminates the scales which cause the degradation of estimation accuracy after the box-counting stage for whole scales available from a binary image. And then the method fits a regression line to the selected points on a log-log plot in order to obtain the estimate of the fractal dimension. Preliminary consideration indicates that the proposed method is less time-consuming than Buczkowski's method. Some experiments with deterministic fractals, random fractals, and Euclidean objects are also conducted to compare the proposed method to conventional ones in terms of estimation accuracy. The results show that the proposed method enables us to obtain more accurate estimates of the fractal dimension of binary images than the BCM and Buczkowski's method.View full abstractDownload PDF (1730K) -
Optimal Location of an Acoustic Sensor for an Accurate Pipe Length Measurement Using Stationary WaveMasayuki OKAMOTO, Farrukh RIZKIYEV, Shogo TANAKA2003 Volume 39 Issue 11 Pages 1010-1015
Published: 2003
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn the field of measurement, we often encounter the need to measure pipe lengths indirectly. We have developed an on-line pipe length measurement system with one acoustic sensor from the viewpoints of ease to be used in various applications and its cost. The system made use of the stationary wave generated by hitting the pipes or the one spontaneously generated in the pipes. The system realized a highly accurate measurement by modeling the stationary wave as state variables of a linear dynamic system and applying Kalman filters and maximum likelihood method.
The paper discusses the optimal location of the acoustic sensor to realize a much higher accurate pipe length measurement. Experiments will show the validity of the optimal sensor location.View full abstractDownload PDF (1746K) -
Hideki OGURA, Haruhiko NUMAJIRI, Kazuaki YAMAZAWA, Jun TAMBA, Masaya I ...2003 Volume 39 Issue 11 Pages 1016-1021
Published: 2003
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA copper freezing-point furnace and four copper freezing-point cells were constructed in our institute. The furnace was consisted of one main heater and two end-heaters. The copper freezing-point cells were open type cells with high-purity graphite crucibles that contained copper of 99.9999% purity. The uncertainty in realizing freezing-point for thermocouple calibration was evaluated using the Pt/Pd thermocouples. The main sources of the uncertainty investigated were reproducibility of the plateau, the temperature distribution in the cell and the impurity effect of the metal. The combined standard uncertainty was estimated to be 20.2mK.View full abstractDownload PDF (1665K) -
Ryosuke TASAKI, Takanori YAMAZAKI, Hideo OHNISHI, Masaaki KOBAYASHI, S ...2003 Volume 39 Issue 11 Pages 1022-1028
Published: 2003
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe automatic weighing of packages in motion is coming to assume greater importance. In the weighing of packages, the sequence of products is generally completely random. Long, short, heavy and light products are passed over the conveyor belt scale in any kind of random sequence. In this paper, an interesting possibility of raising throughput of the conveyor line without increasing the conveyor belt speed is offered by the use of two or three conveyor belt scales (called a multi-stage conveyor belt scale) that are arranged in the line in direct sequence to each other. Through the new measuring technique, a weighing scale can be created which will adjust the conveyor belt length to the product length. The conveyor belt scale usually has maximum capacities of less than 80kg and 140cm, and achieves weighing rates of 150 packages per minute and more. This weighing system consists of the multi-stage conveyor belt scale with load cells and the photo-electric switches which detect the product lengths and the distance between products in sequence, and the control unit with a weight indicator and a mounting frame. The experimental results on the multi-stage conveyor belt scale suggest that the algorithms proposed in this paper are effective enough to practical applications.View full abstractDownload PDF (1471K) -
Hayato NAKADA, Kiyotsugu TAKABA2003 Volume 39 Issue 11 Pages 1029-1038
Published: 2003
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper is concerned with the local stabilization of linear systems with actuator amplitude and rate saturations. Based on the local stability condition due to Takaba, we derive a synthesis condition of a linear time-invariant (LTI) controller for the plant with actuator amplitude and rate saturations under the assumption that the rate saturation is modeled as a nonlinear position-feedback system. It is shown that the present synthesis condition is less conservative than the circle criterion. A numerical example is also included to verify the applicability of the present synthesis methods.View full abstractDownload PDF (1674K) -
Isao KEZOBO, Kazuya OGATA, Yoshiki SUGAWARA, Yoshikazu HAYAKAWA2003 Volume 39 Issue 11 Pages 1039-1047
Published: 2003
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper presents a new input shaping design for flexible system with perturbation of system parameters. Typical input shaping is designed by modal parameters and robust to the modal parameter uncertainties. However, robustness to perturbation of certain interesting system parameters has not been explicitly provided. We formulate the input shaping design problem which minimizes the probable residual vibration under the existance of uncertain parameters, and translate this problem into LMI problem. The new input shaper we propose is experimentally verified on the flexible robot arm.View full abstractDownload PDF (1639K) -
Yasushi IWATANI, Shinji HARA2003 Volume 39 Issue 11 Pages 1048-1053
Published: 2003
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we consider convergence and stability analysis for bimodal piecewise linear (B-PWL) systems. We first show that a necessary and sufficient condition for the origin of 2-dimensional B-PWL systems to be globally asymptotically stable is characterized by eigenvalue loci of the corresponding subsystems. We then discuss its extension to the n dimensional case and derive a necessary condition and a sufficient condition to gurantee convergence of the state of the n-dimensional B-PWL system to the origin.View full abstractDownload PDF (1624K) -
Yusuke FUKAZAWA, Trevai CHOMCHANA, Jun OTA, Hideo YUASA, Tamio ARAI, H ...2003 Volume 39 Issue 11 Pages 1054-1060
Published: 2003
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, region exploration path planning algorithm is proposed. In order for a mobile robot to perform this task, appropriate method to deal with the shape of the working environment, which may be intricate or curved, is necessary. In addition, a robot must be able to re-plan the exploration path as soon as possible when robot encounters unexpected objects. These challenges can be met by approximately expressing the working environment with grid points and regenerating the path using one that was planned beforehand. Simulations are used to demonstrate proposed exploration path planning and re-planning algorithm.View full abstractDownload PDF (4155K) -
Jun TAJIMA, Naohiro YUHARA2003 Volume 39 Issue 11 Pages 1061-1070
Published: 2003
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes recognition systems of driver's intention on choosing steering-control modes, lateral control tasks, and on his/her driving mood, which would be essential part of an intelligent steering-assistance system. The steering-control mode recognition system determines which steering-control mode the driver selects, manual or automatic, by applying a sequential probability ratio test to the time-series of prediction errors in two AR Model of preprocessed steering torque signal. The control task recognition system consists of two recognition subsystems, one utilizes Hidden Markov Model Filter, and the other employs ARMAX Model and statistical testing. The driving mood recognition system calculates an index of relative change of aggressiveness of driving, defined as a weighted sum of moving averages of signals such as vehicle yaw rate, longitudinal acceleration, and driver's remnant. The weights on each factor of the index of relative change of aggressiveness are obtained by using the learning algorithm of Support Vector Machine. The results of simulation study using the data drawn from actual vehicles show that the systems would achieve high recognition capability. Furthermore, the proposed systems show a robustness to the vehicle speed change and variation of control characteristics among drivers.View full abstractDownload PDF (2581K) -
Spherically Equivalent Diameter of the Particle Floating in the AirflowTakayuki SUGITA, Yoshifumi KITAYAMA2003 Volume 39 Issue 11 Pages 1071-1073
Published: 2003
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe devised the particle size measuring method in which flour particles were statically floated in the airflow at a test section. Spherically equivalent diameter of the floating particle was obtained by an elliptical approximation of the image. It was well confirmed by the study that the measuring time was reduced to one third and that the accuracy of the equivalent particle diameter acquired by the floating method was of a good consistency with our established Laser-used 3-dimensional particle size measuring method.View full abstractDownload PDF (1500K)
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