Abstract
〈Vol.3 No.3(2010.5)〉
Titles
[Contributed Papers]
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■ Generalized Minimum Variance Control for MIMO System with Multiple Sampling Periods
Tokyo Metroporitan University・Satoshi BESSHO,
Fukuyama University・Masayoshi DOI,
and Tokyo Metroporitan University・Yasuchika MORI
This paper proposes a new control technique for Multi-Inputs Multi-Outputs
(MIMO) systems with multiple time delays. The control design method is
the Generalized Minimum Variance Control (GMVC). As for MIMO systems, it
is assumed that time constants are different greatly each other. In this
case, setting a suitable sampling period in every control loop, we can
reduce computational complexity very much keeping the effective performance.
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■ Self-Tuning Continuous-Time Generalized Minimum Variance Control
Tokyo Metropolitan University・Ryota HOSHINO and Yasuchika MORI
The generalized minimum variance control (GMVC) is one of the design methods
of self-tuning control (STC).In general, STC is applied as a discrete-time
(DT) design technique. However, by some selection of the sampling period,the
DT design technique has possibilities of generating unstable zeros and
time-delays, and of failing in getting a clear grasp of the controlled
object. For this reason, we propose a continuous-time (CT) design technique
of GMVC, which we call CGMVC. In this paper, we confirm some advantages
of CGMVC, and provide a numerical example.
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■ Improving Measurement Accuracy of Long Baseline Differential GPS
Keio University・Takashi MATSUSHITA and Toshiyuki TANAKA
The global positioning system (GPS) is a 3D positioning system using space
satellites. It provides location information for navigation systems, location
surveys, and so on. GPS uses two types of measuring methods; stand-alone
positioning and relative measurement using another receiver with a known
position. We focus on the method called differential GPS (DGPS), which
is a relative measurement technique, because the measurement accuracy of
DGPS is generally better than that of stand-alone positioning. However,
when the baseline used in DGPS becomes long, the positioning error increases.
Therefore, we propose to improve the accuracy in the measurement of the
long baseline DGPS. For precise positioning by the long baseline DGPS,
we use weighting coefficients of the elevation angle to satellites in the
calculation and correct DGPS-specific bias errors by the proposed method.
It is shown that we succeed in improving the measurement accuracy of the
long baseline DGPS.
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■ Stochastic Optimal Tracking with Preview by State Feedback for Linear
Continuous-Time Markovian Jump Systems
Osaka University・Gou NAKURA
In this paper we study the stochastic optimal (LQG) tracking problems with
preview for a class of linear continuous-time Markovian jump systems. The
systems are described as continuous-time switching systems with Markovian
mode transitions. Necessary and sufficient conditions for the solvability
of our LQG tracking problems are given by coupled Riccati differential
equations and coupled scalar 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 our design method.
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■ Reflection Wave Suppression in Frenkel-Kontrova Model Simulation : Analysis Based on the GKYP Lemma
Tokyo Institute of Technology・Takayuki ISHIZAKI,
Kenji KASHIMA, and Jun-ichi IMURA
The Frenkel-Kontorova model is a nonlinear lattice model to represent extremely
complicated behaviors such as a dislocation in crystal and DNA structures.
This model is given as the dynamical system composed of infinitely many
bonded particles. Thus, a spatially restricted model is used in numerical
simulations of this model. However, a phenomenon called a reflection wave,
which will occur at the boundary due to this finite approximations, is
known to considerably degrade computational precision in the simulation.
This paper thus proposes a method to analyze a property of this reflection
wave via the Generalized Kalman-Yakubovich-Popov (GKYP) lemma.
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■ Study on the Realization of Indium Point
AIST・Januarius V. WIDIATMO, Kazuaki YAMAZAWA,
Kouichi SATOU, Jun TAMBA, and Masaru ARAI
Indium point cells are fabricated using ingots of various forms from a
variety of sources (manufacturers). Using these cells, newly built indium
point furnaces are evaluated and their reliability is confirmed. The indium
point realizations based on the single solid-liquid method (SSL method)
and multi solid-liquid method (MSL method) are evaluated. The effect of
impurities in the ingots is evaluated from the dependency of the slope
of the freezing curve on the change in furnace temperature, the indium
point depression based on the impurity analysis, and the cell comparison.
The results show equality among the cells. Based on the results obtained,
the uncertainty in realizing the indium point using the described indium
point cells and indium point furnaces is estimated. The new uncertainty
budget introduces uncertainties coming from plateau repeatability and chemical
impurity derived by the present work, the values of which are significantly
lower than those adopted in the current calibration service.
▲ ■ Tool Difference Transition Visualization for Semiconductor Manufacturing
Shibaura Institute of Technology
/Toshiba Corporation・Tomoaki KUBO,
University of Tokyo・Masateru MINAMI,
and Shibaura Institute of Technology・Tetsuya HOMMA
Reducing tool differences is one of the important tasks to improve the
yield of semiconductor device manufacturing. Various kinds of methods have
been proposed to solve this problem. These methods enable us to find problematic
tools from numbers of process tools. However, finding problematic tools
is not always enough to work out the problem of tools. Visualization of
the transition profile of tool differences provides us additional information
to help finding the unknown control parameters. It helps us to find corresponding
events such as maintenance, repair, and adjustment. We design a profiling
algorithm based on the maximum likelihood estimation. This algorithm introduces
a new constraint that “tools are stable at each process step for a short
period”, and recursively uses a regression method by employing previous
results of the estimation. Simulation results show that our algorithm extracts
the transition profile of tool differences more precisely than existing
regression methods.
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■ Next Generation HVAC System
Toshiba Corporation・Yasuo TAKAGI, Yoshiki MURAKAMI,
Yuuichi HANADA, Nobutaka NISHIMURA,
Kenichi YAMAZAKI, and Yasuyuki ITOH
A new HVAC (Heating, Ventilating, and Air-Conditioning) system for buildings
is proposed. The key technology for the system is a twin coil air handling
unit (AHU) and its advanced control method. One coil is equipped to cool
and dehumidify the fresh air intake, and the other coil is for cooling
circulated air. The deeply chilled water is necessary only for removing
the moisture from the fresh air. The latter coil requires moderately cool
water according to the HVAC load. Then 2 kinds of chilled water in terms
of temperature should be prepared. The structure helps saving the energy
consumption for air-conditioning because the higher chilled water temperature
implies the better chiller efficiency (COP:Coefficient of Performance).
In addition, an advanced control method that is called an ‘Air-Water cooperation
system’ is introduced. The control system mainly focuses on energy savings
through changing the temperature of the chilled water and supply air according
to the HVAC load and weather conditions. In this paper, we introduce a
Next Generation HVAC system with its control system and present evaluation
results of the system for the model-building simulator.
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■ Dynamics of Grasping a Rigid Object with Arbitrary Smooth Surfaces under Rolling Contacts
Ritsumeikan University・Suguru ARIMOTO
Modeling and control of dynamics of three-dimensional object grasping by
using a pair or triplet of multijoints robot fingers are investigated under
rolling contact constraints and arbitrary shapes of the object and fingertips.
It is assumed that a rolling contact between two rigid bodies with smooth
surfaces is governed by the condition that the two surfaces coincide at
the common contact point and share the same tangent plane. The contact
constraint expressing the contact of the two surfaces at a single point
in the 3-dimensional Euclidean space is reinterpreted by a set of three
Pfaffian constraints, one of which is a velocity equivalence in the normal
to the tangent plane at the contact point and the other two are velocity
equivalence relations on the tangent plane. The Euler-Lagrange equation
of motion of the overall fingers/object system is derived by introducing
Lagrange multipliers corresponding to those Pfaffian constraints together
with update laws of length parameters of loci of each contact point on
the fingertips and object surfaces. It is shown that the Euler-Lagrange
equation is parameterized by the length parameters through quantities of
the first fundamental form of the surfaces, but the update laws of length
parameters are governed by quantities of the second fundamental form.Furthermore,
it is shown that the rolling constraints are directionally integrable.
In accordance with this result, a control signal for maintaining contacts
with the object is suggested from the standpoint of fingers-thumb opposability.
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■ Implementation of an Efficient High-Accuracy Model for Personal GPS
Receivers
Keio University・Masashi YONEKAWA and Toshiyuki TANAKA
Positioning systems supported by satellites are increasingly used because
of the widespread use of cheap and small personal Global Positioning System
(GPS) receivers. Personal GPS receivers are used in cellular phones and
car navigation systems. The positioning method used by these personal GPS
receivers often produces inaccurate positioning results. Because of the
price and size constraints of personal GPS receivers, their accuracy is
compromised, and as a result, high-accuracy positioning methods are not
widely used. In this paper, we propose a high-accuracy positioning method
that can be used with personal GPS receivers. Our proposed method is based
on a new approach that takes into account both the systems and solar wind
environments. To verify our method, we target the positioning accuracy
equivalent to that of the dual-frequency positioning system, which is the
highest-accuracy positioning method among all standalone positioning methods.
Our approach is implemented in software only, meaning it can be implemented
in even the most widely used GPS receivers. Processing speeds associated
with the implementation of our proposed method using the CPUs of cellular
phones and car navigation systems are well-tolerated.
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■ Sub-Volumetric Classification and Visualization of Emphysema Using a
Multi-Threshold Method and Neural Network
Keio University・Kok Liang TAN, Toshiyuki TANAKA,
Tokyo Electric Power Hospital・Hidetoshi NAKAMURA,
Keio University・Toru SHIRAHATA, and Hiroaki SUGIURA
Chronic Obstructive Pulmonary Disease is a disease in which the airways
and tiny air sacs (alveoli) inside the lung are partially obstructed or
destroyed. Emphysema is what occurs as more and more of the walls between
air sacs get destroyed. The goal of this paper is to produce a more practical
emphysema-quantification algorithm that has higher correlation with the
parameters of pulmonary function tests compared to classical methods. The
use of the threshold range from approximately ?900 Hounsfield Unit to ?990
Hounsfield Unit for extracting emphysema from CT has been reported in many
papers. From our experiments, we realize that a threshold which is optimal
for a particular CT data set might not be optimal for other CT data sets
due to the subtle radiographic variations in the CT images. Consequently,
we propose a multi-threshold method that utilizes ten thresholds between
and including ?900 Hounsfield Unit and ?990 Hounsfield Unit for identifying
the different potential emphysematous regions in the lung. Subsequently,
we divide the lung into eight sub-volumes. From each sub-volume, we calculate
the ratio of the voxels with the intensity below a certain threshold. The
respective ratios of the voxels below the ten thresholds are employed as
the features for classifying the sub-volumes into four emphysema severity
classes. Neural network is used as the classifier. The neural network is
trained using 80 training sub-volumes. The performance of the classifier
is assessed by classifying 248 test sub-volumes of the lung obtained from
31 subjects. Actual diagnoses of the sub-volumes are hand-annotated and
consensus-classified by radiologists. The four-class classification accuracy
of the proposed method is 89.82%. The sub-volumetric classification results
produced in this study encompass not only the information of emphysema
severity but also the distribution of emphysema severity from the top to
the bottom of the lung. We hypothesize that besides emphysema severity,
the distribution of emphysema severity in the lung also plays an important
role in the assessment of the overall functionality of the lung. We confirm
our hypothesis by showing that the proposed sub-volumetric classification
results correlate with the parameters of pulmonary function tests better
than classical methods. We also visualize emphysema using a technique called
the transparent lung model.
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