Abstract
〈Vol.3 No.4(2010.7)〉
Titles
[Contributed Papers]
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■ Determining Magnetic Field Close to Air-bearing Surface by Projection
Electron-beam Tomography and Fourier Extrapolation
Osaka University/ Hitachi Ltd.・Hiroyuki SHINADA,
Osaka University・Yoshihiro MIDOH,
Hitachi Ltd.・Tomokazu SHIMAKURA,
and Osaka University・Koji NAKAMAE
The magnetic field of a recording head is measured by projection electron-beam
tomography with a resolution of about ten nanometers, and the magnetic
field closer to the sample surface than the measurement plane is estimated
by numerical calculation. The magnetic field at 20 nm calculated from the
field measured at 50 nm adequately agrees with the directly measured field
at 20 nm. The combination of projection electron-beam tomography and this
calculation method make it possible to determine the magnetic field close
to a head (air-bearing) surface.
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■ Experimental Validation of Switching Strategy for Tracking Control with
Collision Avoidance in Non-cooperative Situation Using Toy Model Cars
Nara Institute of Science and Technology・
Kiminao KOGISO, Makoto NOGUCHI,
Kazuyoshi HATADA, Naoki KIDA,
Naofumi HIRADE, and Kenji SUGIMOTO
This paper presents some experimental validation results of the already-proposed switching control method for simultaneous achievement of collision avoidance and tracking control for a vehicle in a non-cooperative situation. To validate the method, an experimental control system is made, in which the vehicle is a toy model car possible to remotely control via infrared ray and a camera is used to measure the vehicle's state. After presenting the constructed control system, the method's effectiveness is investigated with the results obtained from the several control experiments.
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■ Temperature Control of Deionized Water Heater as a Class of Serial Processes
KELK Ltd.・Kazuhiro MIMURA,
Tokyo Denki University・Tetsuo SHIOTSUKI,
and Kumamoto University・Shigeyasu KAWAJI
Serial processes are one of the important class of MIMO processes. We propose a combined control technique of PID control and disturbance observer for the temperature control of deionized (DI) water heater that has the structure of serial process. The results of both simulation and actual equipment experiment verifies that the proposed method enables not only to use fewer temperature sensors than the conventional system but also to solve the offset problem that is typical for the serial processes.
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■ A Quasi-ARX Neural Network with Switching Mechanism to Adaptive Control
of Nonlinear Systems
Waseda University・Lan WANG, Yu CHENG, and Jinglu HU
This paper introduces an improved quasi-ARX neural network and discusses its application to adaptive control of nonlinear systems. A switching mechanism is employed to improve the performance of the quasi-ARX neural network prediction model which has linear and nonlinear parts. An adaptive controller for a nonlinear system is established based on the proposed prediction model and some stability analysis of the control system is shown. Simulations are given to show the effectiveness of the proposed method both on stability and accuracy.
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■ Fixed-Structure H∞ Controller Synthesis Based on the Covariance Matrix
Adaptation Evolution Strategy
Yamaguchi University・Yuji WAKASA, Shinji KANAGAWA,
Kanya TANAKA, and Yuki NISHIMURA
This paper provides a design method of fixed-structure controllers satisfying
multiple $H_{\infty}$ norm specifications by using the covariance matrix
adaptation evolution strategy (CMA-ES). The CMA-ES is a kind of stochastic
optimization such as particle swarm optimization (PSO), and has been shown
to have a good performance for nonconvex optimization problems. However,
there are few control applications of the CMA-ES, and therefore, its superiority
is not clear in control problems. The effectiveness of the proposed method
is demonstrated through numerical examples in comparison with the PSO-based
method that has recently been proposed as a good approach.
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■ Stability Analysis of Sampled-Data Systems with Static Sector Nonlinearities
via Causal Linear Periodically Time-Varying Scaling
Kyoto University・Kenichi MORIOKA
and Tomomichi HAGIWARA
This paper is concerned with causal linear periodically time-varying (LPTV)
scaling for stability analysis. The effectiveness of such a scaling technique
was first shown for the robust stability analysis of linear sampled-data
systems, and it was then extended to a more general technique called noncausal
LPTV scaling. Even though noncausal LPTV scaling has been shown to be more
effective than causal LPTV scaling in such a context, this paper aims at
showing that causal LPTV scaling, unlike noncausal LPTV scaling, can be
applied even to sampled-data systems with static sector nonlinearities.
Numerical examples are also studied to compare the effectiveness with another
method based on the conventional multiplier technique.
▲ ■ Fuzzy Logic Based Autonomous Parallel Parking System with Kalman Filtering
University of Technology Thonburi・
Benjamas PANOMRUTTANARUG,
and University of Electro-Communications・
Kohji HIGUCHI
This paper represents an emulation of fuzzy logic control schemes in autonomous
parallel parking system in a backward maneuver. There are four infrared
sensors sending the distance data to a microcontroller for generating an
obstacle-free parking path. Two of them mounted on the front and rear wheels
on the parking side are used as the inputs to the fuzzy rules to calculate
a proper steering angle while backing. The other two attached to the front
and rear ends serve for avoiding collision with other cars along the parking
space. At the end of parking process, the vehicle will be in line with
other parked cars and position in the middle of the free space. A construction
of fuzzy rules is designed based upon a wall following process. Performance
of the infrared sensors is improved using Kalman filtering. The design
method needs extra information from ultrasonic sensors. Starting from modeling
the ultrasonic sensor in 1-D state space forms, one makes use of the infrared
sensor as a measurement to update the predicted values. The experimental
results demonstrate the effectiveness of sensor improvement.
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■ On Almost Orbital Equivalence of Nonlinear Systems
Osaka University・Masato ISHIKAWA,
Railway Technical Research Institute・
Teruya YAMAGUCHI,
and Kyoto University・Toshiharu SUGIE
This paper is concerned with equivalence of nonlinear systems from a viewpoint of geometric congruence of system orbits in the state space. The notion of orbital equivalence had been originally exploited by Sampei and Furuta in the context of the time-scale transformation approach. They gave a fundamental characterization of orbital equivalence in the form of a similarity conditions of the system vector-fields; however, it was not satisfactory in the sense that there remains significant gap between the necessary condition and the sufficient one, mainly due to its treatment of unavoidable singularity of the time-scale functions.
In this paper, we intend to cast a new light on this problem with the aid of almost point of view that neglects the inconsistency on measure zero subsets. By introducing the notions of almost orbital equivalence and the almost similarity of the vector-fields, we provide the sole necessary and sufficient conditions connecting them. Furthermore, we discuss the combination of the orbital equivalence analysis and stability issue based on the recent development of the density function approach for stability analysis. The discussion is also illustrated by numerical examples.
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■ Detection of Ceramic Cracks Using a Distributed High-Resolution Brillouin Fiber Optic Sensor
University of California・Maria FENG,
OZ Optics Ltd.・Lufan ZOU,and
University of California・Michio IMAI
A distributed sensor system is highly desirable for detecting, locating,
and monitoring fine cracks at unknown locations in advanced ceramics. This
paper presents a distributed high-resolution fiber optic sensor based on
the Brillouin scattering principle, and its application in ceramic crack
detection for the first time. The existence of cracks, together with their
locations, is identified by measuring the strain distribution on a sensing
fiber bonded to the ceramic surface. By employing the innovative coherent
probe-pump interaction technique, the Brillouin sensor developed in this
study achieves a high spatial resolution (100 mm) and measurement accuracy.
Capable of detecting and locating fine cracks less than 40 micrometer,
the efficacy of the distributed Brillouin fiber optic sensor is demonstrated
through experiments.
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■ Gain-Scheduled State-Feedback Controllers Using Inexactly Measured Scheduling Parameters: Stabilizing and H∞ Control Problems
Japan Aerospace Exploration Agency・Masayuki SATO
This paper tackles two design problems, i.e. stabilizing and H∞ control
problems, using Gain-Scheduled (GS) state-feedback controllers for Linear
Parameter-Varying (LPV) systems under the condition that the scheduling
parameters are inexactly measured. The LPV systems are supposed to have
polynomially parameter-dependent state-space matrices and the measured
scheduling parameters are supposed to have a priori defined bounded uncertainties.
Using parameter-independent Lyapunov functions and parameter-dependent
scaling matrices related to the uncertainties in the measured scheduling
parameters, we give formulations for designing parametrically affine GS
stabilizing and H∞ state-feedback controllers in terms of parametrically
affine Linear Matrix Inequalities (LMIs). Our proposed methods encompass
the design methods of robust state-feedback controllers as a special case.
A simple numerical example for H∞ control problem is included to illustrate
our results.
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■ An Outlier Removal Method for SPC in Semiconductor Manufacturing
Shibaura Institute of Technology/Toshiba Corporation・
Tomoaki KUBO,
University of Tokyo・Masateru MINAMI,
and Shibaura Institute of Technology・Tetsuya HOMMA
To maintain stable operation of semiconductor fabrication lines, statistical
process control (SPC) methods are recognized to be effective. In semiconductor
fabrication lines, there exist a huge number of process state signals to
be monitored, and these signals contain both normally and non-normally
distributed data, which is making the application of SPC difficult. We
have already proposed an SPC method "ESCM" which can solve these
problems. However, this method has a problem that it is highly sensitive
to outliers contained in the reference data. In this paper, we propose
a new outlier removal method to solve this problem. This method uses "effective
standard deviation" we used in the ESCM to deal with a wide range
of non-normal distribution. Basic performances of this method are demonstrated
by comparing abilities to detect outliers correctly, and not to mistakenly
detect non-outlier data. In the demonstration, we use various kinds of
artificially generated data, and real data observed in process tools in
a semiconductor fabrication line. Usefulness of this method is demonstrated
by studying the effects of this method when used with ESCM.
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