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Volume 46, Issue 12
Displaying 1-9 of 9 articles from this issue
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Paper
Measurement
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Shuichi OHSAWA, Hisakazu NAKAMURA, Hirokazu NISHITANI2010 Volume 46 Issue 12 Pages 733-736
Published: 2010
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSSelf-localization is an important technique for vehicle automation. Extended Kalman Filtar (EKF) is a major sensor fusion technique for self-localization of mobile vehicles. To calculate Kalman gains, variance matrices are necessary. However, it is laborious to obtain variance matrices. In this paper, we compare the structure of the grid point observer with that of EKF, and propose a design method of decding variance matrices by using digital filter design method. In addition, effectiveness of the proposed method is confirmed by the experiments.View full abstractDownload PDF (376K) -
Tetsuya KON, Michiko NISHIYAMA, Taketoshi IYOTA, Junichi MATSUZAKI, Ka ...2010 Volume 46 Issue 12 Pages 737-745
Published: 2010
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSThis paper describes performances of fiber optic sensor modules developed for a sensor network system embedded into living spaces where an intelligent ubiquitous service would be offered. Three types of fiber-optic sensor modules are developed as a so-called optical nerve sensor network, in order to acquire presence information which can indicate the condition of human, structural materials and other stuffs in common living space. The sensor modules are successfully realized in the forms of a plastic tiled mat, a cushion and a binary switch, taking advantages of a hetero-core fiber optic technique which enables easy arrangement into our living space. The sensor modules can bring us effective presence information in terms of the weight and temporal profiles of human and space conditions in their natural and unconstrained behavior. The practical performance and advantage of this sensor network system have been verified from the service experiments performed in a test field where the sensor modules were installed in realistic density.View full abstractDownload PDF (2063K) -
Toshiro NAKASHIMA, Hajime NAKAJIMA, Kazuhiko SUMI, Osamu MATOBA2010 Volume 46 Issue 12 Pages 746-753
Published: 2010
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSWe have developed a road surface condition detection system using near-infrared light, which enables remote measurement. The developed system can detect the difference of road surface conditions as dry, water, ice, and snow.
In this case, we focused on the light-absorption characteristics of water. To remove the affect of the thickness of the water layer, we have proposed a measured metrics as absorption ratio at two wavelengths. The absorption spectra were measured by using a water layer of 1mm thickness. The experimental results showed that the absorption peak shifts to longer wavelength when the water state changes into ice state. A ratio of absorption coefficients at 1300nm and 1410nm is constant even when the layer thickness changes from 0.2mm to 0.8mm. This result indicates that the proposed absorption ratio can be used as a criterion to detect the water state or the ice state.
We have also proposed a reflected-light separation method by using polarization characteristics of light. There are two reflected light components. One is the reflected light from the water surface and the other is one from the road surface. The reflected light from the water surface keeps the polarization state of the input. However, the polarization state from the road surface becomes random state because of the rough surface. To remove the surface reflection of the water layer, orthogonal polarization detection of input and output pair is effective. This is confirmed by the experiment.
We made a prototype of the above-described detection principle and it was tested by the experiment. As a result, the feasibility of determining road surface conditions such as dry, water and ice is confirmed by simultaneous measurement of light-absorption characteristics and reflection characteristics.View full abstractDownload PDF (1034K) -
Hiroyuki ONO2010 Volume 46 Issue 12 Pages 754-758
Published: 2010
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSThis paper describes a high frequency PLL (Phase Locked Loop) synthesizer with a function of learning then eliminating repeatable fluctuation of timing intervals on series input pulses. Typical spindle encoder generates digital pulses according to the revolution speed. The intervals of each pulse have repeatable fluctuation every revolution by eccentricity or warpage of the encoder scale disk. This method provides a programmable counter for the loop counter of PLL circuit and an interval counter with memory in order to learn the repeatable fluctuation. After the learning process, the PLL generates very pure tone clock signal based on the real flutter components of the spindle revolution speed without influenced by encoder errors. This method has been applied to a hard disk test system in order to generate 3GHz read/write clock.View full abstractDownload PDF (1645K)
Control
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Tatsuya KAI, Shinji HARA2010 Volume 46 Issue 12 Pages 759-764
Published: 2010
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSThis paper addresses analysis of nonlinear kinematic systems subject to nonholonomic affine constraints based on nonlinear control theory. We first give some definitions and concepts on affine constraints and affine/non-affine variables. Next, nonholonomic kinematic systems with affine constraints (NKSAC), which are kinematic models of systems subject to the affine constraints, are derived. We then analyze the NKSAC from the viewpoint of nonlinear control theory. Especially, we focus on local accessibility, local controllability and local asymptotic stabilizability of the NKSAC. Finally, some physical examples are shown in order to confirm our results.View full abstractDownload PDF (380K) -
Gou NAKURA2010 Volume 46 Issue 12 Pages 765-773
Published: 2010
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSIn order to design tracking control systems for a class of systems with rapid or abrupt changes, it is effective in improving tracking performance to construct preview control systems considering future information of reference signals. In this paper we study the H∞ tracking problems with preview for a class of linear continuous-time Markovian jump systems by the game theoretic approach. The systems are described by the continuous-time switching systems with Markovian mode transition. The necessary and sufficient conditions for the solvability of the H∞ tracking problem by state feedback are given by coupled Riccati differential equations with terminal conditions. Correspondingly feedforward compensators introducing future information are given by coupled differential equations with terminal conditions. We consider three different tracking problems depending on the property of the reference signals. Finally we give numerical examples and verify the effectiveness of the design theory presented in this paper.View full abstractDownload PDF (764K) -
Takayuki ISHIZAKI, Kenji KASHIMA, Jun-ichi IMURA2010 Volume 46 Issue 12 Pages 774-782
Published: 2010
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSIn this paper, we propose a model order reduction method for SISO linear dynamical networks, where a large number of subsystems are interacted according to a network. In this method, the structure of spatially one-dimensional reaction-diffusion that a SISO linear dynamical network intrinsically has is extracted by way of Householder transformation ordering the state variables according to the distance from the source (i.e., an input) of the diffusion. Based on this structure, a model order reduction method with the diffusion structure of the system preserved is presented, which can be applied for large-scale systems. In addition, an easily-computable error bound via the proposed model reduction is derived.View full abstractDownload PDF (940K) -
Kenji FUJIMOTO, Yuko HASEGAWA2010 Volume 46 Issue 12 Pages 783-790
Published: 2010
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSThis paper is concerned with a consensus problem for large scale network systems. Our goal is to design the feedback gains of each system as a function of its degree in such a way that the rate of convergence takes its maximum. We propose a new criteria called normalized eigenvalue variance as the measure of the convergence speed of a large scale network with many agents. It permits an assessment of the convergence performance of homogeneous graphs. We demonstrate the design method of the agents' feedback gains minimizing the normalized eigenvalue variance.View full abstractDownload PDF (426K)
System Integration
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Kohei FUNAI, Koji MIZOUE, Mitsuru HIGASHIMORI, Makoto KANEKO2010 Volume 46 Issue 12 Pages 791-796
Published: 2010
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSActive Strobe Imager enables us to visualize the dynamic behavior of tissue, even under a high frequent vibration that cannot be followed by the naked eye. A pneumatic actuator imparts a vibration to the target object. By flashing light with a slightly different frequency from the object frequency, we can see the dynamics of object by the naked eye. The vibration we can observe depends on various parameters such as frequency and duty ratio. We formulate the parameter optimization problem by considering the observability of object under strobe condition. By applying the full search method for the problem, we discuss the optimum set of parameters. We also confirmed the effectiveness of the optimized parameters through experiment.View full abstractDownload PDF (2183K)
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