Abstract
〈Vol.1 No.3(2008.5)〉
Titles
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■ Challenges in Control Engineering for Innovative Process Industries
Toshiaki Itoh
Driven by the needs of innovative process industries, the role of control engineering in process industries is being expanded. In this article, the gaps between emerging needs and the current process control technology are discussed, which are summarized in “protective control”, “process and product control” and “plant- and business-wide control”. The effort to reduce these gaps promises a bright future for control engineering.
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■ Evolution of Autonomous Decentralized Systems for Information and Control
Hitachi, Ltd.・Motohisa Funabashi, Katsumi Kawano, Shigetoshi Sameshima
and Hiromitsu Kato
This paper presents our experiences over the past three decades with the
development of information and control systems based on the concept of
autonomous decentralized systems. The autonomous decentralized system concept
was born in the late 1970s stimulated by the emergence of microprocessors,
which suggested a decentralized information and control system architecture
with a publish/subscribe communication model. Successful applications to
manufacturing systems as well as so-cial infrastructure systems created
the current dedicated architectures which are focused on achieving intelligent
communication fields for meeting large-scale ever-changing plants with
capabilities enabling collaboration with stakeholders as well as integration
of ubiquitous devices.
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■ Technologies for Achieving Field Ubiquitous Computing
Yokogawa Electric Corporation・Akira Nagashima
Although the term “ubiquitous” may sound like jargon used in information appliances, ubiquitous computing is an emerging concept in industrial automation. This paper presents our visions of field ubiquitous computing, which is based on the novel Internet Protocol IPv6.
IPv6-based instrumentation will realize the next generation manufacturing excellence. This paper focuses on the following five key issues: 1. IPv6 standardization; 2. IPv6 interfaces embedded in field devices; 3. Compatibility with FOUNDATION fieldbus; 4. Network securities for field applications; and 5. Wireless technologies to complement IP instrumentation.
Furthermore, the principles of digital plant operations and ubiquitous production to support the above key technologies to achieve field ubiquitous systems are discussed.
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■ Development of an Operation Support System for the Blast Furnacein the
Ironmaking Process:Large-scale Database-based Online modeling and Integrated
Simulators
Waseda University・Harutoshi Ogai, Masatoshi Ogawa, Kenko Uchida,
NIPPON STEEL CORPORATION・Shinroku Matsuzaki and Masahiro Ito
In the pig-ironmaking process, factors that cause operation malfunctions
have increased with both the enlargement of the blast furnace and the increasing
use of low quality ore. Therefore, operation support system that predict
blast furnace performance is demanded. This paper reports the development
of a blast furnace operation support system with an integrated simulator
and “Large-scale database-based Online Modeling (LOM)”. To develop the
integrated simulator, a sophisticated burden distribution model is integrated
with a two-dimensional total internal phenomenon model for the stationary
state by using Java technology. Moreover, an integrated simulator for the
partial non-stationary state is developed by modifying the two-dimensional
total internal phenomenon model for the stationary state. To incorporate
the LOM system into the operation support system, a cross-platform LOM
system with general versatility is rebuilt by an existing LOM system. The
operation support system is realized by the simulator of the physical modeling
method and the LOM of the local modeling method. As a result, the operation
support system predicts a dynamic molten pig-iron temperature in the blast
furnace. The operation support system is expected to provide staff with
useful information.
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■ Hierarchical Model Predictive Control applied to a Cement Raw Material
Mixing Process
Toshiba Corporation・Yutaka Iino, Aso Cement Co., Ltd・Koichi Abe and Yasuhisa
Tsukamoto
A practical model predictive control method is proposed which was applied to a cement raw material mixing process. The method has a hierarchical structure of 3 layers consisted of set point calculation with an optimizer, multi-input multi-output material mixing ratio control system with the Model Predictive Control scheme, and DCS local control system with PID controllers. It realized priority management of multi-objective control specifications and constraints, avoidance of infeasibility in optimization, handling of control degree of freedom, feed-forward control for transient manipulation, and adaptation to the time-varying components in each raw material with Kalman filtering estimator. A 72-hour test operation was executed for a real plant with regular raw materials and some additive industrial waste materials, which revealed good control performance and reached an economical optimal operation point automatically.
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■ Design of a Multiloop One-Spot Tuning of PID Controller and its Application
for a Crude Distillation Unit
Idemitsu Kosan, Co. Ltd・Kenzo FUJII and Hiroshima University・Toru YAMAMOTO
In petroleum refineries and petrochemical processes, reducing production
costs key increasing competitiveness. Previously, the authors proposed
the cyclic one-spot tuning PID control scheme for single-input and single-output
systems, and applied it to the atmospheric distillation tower. The effectiveness
of the proposed control scheme has been verified in steady operation mode.
However, satisfactory performance could not be obtained when the operation
mode was switched to transition operation mode. In order to overcome this
problem, it is necessary to consider the influence of the interactions
upon each input and each output. This paper presents a new multiloop one-spot
tuning PID control scheme with a static pre-compensator. According to the
newly proposed control scheme, satisfactory control performance can be
obtained in both the steady and the transition operation modes.
▲ ■ Optimal Path Generation Method for Automotive Collision Avoidance System
Using Mixed Integer Programming
Kyushu University・Masakazu MUKAI*Junichi MURATA ,Taketoshi KAWABE,
Nissan Motor Co. Ltd・Hikaru NISHIRA,Yoshitaka TAKAGI and Yoshitaka DEGCHI
This paper considers an optimal path generation problem that generates
a path of an automobile without any collision with obstacles. The problem
is formulated as a mixed integer programming problem. In the problem the
obstacles and environments around the automobile can be represent as inequality
conditions. The dynamics of the obstacle is described as variation of a
prohibited region. According to model predictive control we solve the optimal
path generation problem at each time step then apply the first element
of the optimal input. The method proposed in this paper can deal with an
explicit representation of the dynamics of the obstacle and provides no
collision between the automobile and the obstacle.
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■ Plant Modeling Environment Based on Conservation Laws and Projection Method for Automotive Control Systems
Toyota Motor Corp・Akira Ohata,Hisashiro Ito,
Emmeskay Inc.・Swaminathan Gopalswamy,Tokyo Denki University・Katsuhisa
Furuta
A lumped parameter plant modeling based on fully combined physical domains has been proposed as a key technology of MBD (Model-Based Development). The method derives a physical model strictly defined as the one to satisfy the relevant conservation laws. To execute the model, symbolical equation handling is applied because it derives the nonlinear differential algebraic equations. Projection method has been combined to make the mechanical system modeling flexible.
▲ ■ A Command Generation Method of Point-to-Point Control for Suppressing
Residual Vibration
Mitsubishi Electric Corporation・Koichiro UEDA,
Hidetoshi IKEDA,Hiroshi SUGIE and Takashi IWASAKI
A Command Generation Method of Point-to-Point (PTP) control is presented
for suppressing mechanical residual vibration and positioning machine load
at a designated time. A time domain property of commands to suppress residual
vibration is analyzed. This property shows that relation command shapes
and vibration are important to suppress residual vibration, and selection
of command shape depending on positioning time is necessary to suppress
residual vibration. By using this property, concrete command generation
methods are proposed. Proposed commands for suppressing residual vibration
are formulated simply, and require few computational resources to be generated.
Experimental results are presented to verify the effectiveness of the proposed
commands..
▲ ■ A Design Method of a Full Closed Loop Sampled Servo Control for Hard
Disk Drive
Hitachi Global Storage Technologies・Takashi YAMAGUCHI
and Hitachi, Ltd.・Takenori ATSUMI
This paper presents a design methodology for fast and precise positioning
using a full closed loop sampled servo control system. A servo control
of hard disk drives (HDD) achieves 3-4 ms fast access and nanoscale positioning
accuracy. To achieve the nanoscale precise positioning, a full closed loop
feedback control is a key structure. From control theory viewpoint, the
full closed loop is an ideal method, but it is difficult to take this method
in industries due to sensor allocation. In HDD, this full closed loop feedback
control has been applied for last 20 years. The full closed loop sometimes
brings drawbacks to the servo control design. In HDD case, that is a limited
sampling rate selection. In this paper, based on these two features which
are the full closed loop and a sampled servo, uniquely developed servo
design methods for HDD are presented, which include two-degrees-of-freedom
(TDOF) controller with multi-rate sampling, reference trajectory design
not to excite higher order mechanical resonances, settling servo to compensate
for tracking error near the target, phase stabilized design of feedback
control to have better sensitivity, and multi-rate filter design to suppress
disturbances above the Nyquist frequency.
▲ ■ An Indoor Position Estimation Method by Maximum Likelihood Algorithm
using Received Signal Strength
Yamatake Corporation・Isao YAMADA,Keio University・Tomoaki OHTSUKI ,
Yamatake Corporation・Tetsuo HISANAGA and Li ZHENG
A lot of applications of sensor networks require the positions of human
and objects in indoor environments. There are some methods for this purpose.
In this paper, we use received signal strength (RSS) to estimate the position
for its simplicity. However, RSS varies substantially owing to fading,
shadowing, multipath effects and so on. Attenuation coefficient varies
according to indoor environment. For this reason, the attenuation coefficient
is determined before estimating the position of a target node in the conventional
method. We propose a position estimation method that estimates a target
node position and an attenuation coefficient simultaneously. Thus, the
proposed method has no need to estimate the attenuation coefficient in
the target environment preliminarily. To evaluate the position estimation
accuracy of the proposed method, we developed the prototype system and
experimented in our office. Multiple fixed target nodes were set in the
target environments. The experiments show that the proposed method has
about the same accuracy as the conventional one without preliminary data
collection for attenuation coefficient estimation.
▲ ■ Health Management Technology as a General Solution Framework
Omron Corporation・Hiroshi Nakajima, Yoshifumi Hasegawa,
Hiroshi Tasaki, Taro Iwami, Naoki Tsuchiya
Health maintenance and improvement of humans, artifacts,and nature are
pressing requirements considering the problems human beings have faced.
In this article, the health management technology is proposed by centering
cause-effect structure. Important aspect of the technology is evolvement
through human-machine collaboration in response to changes of target systems.
One of the reasons why the cause-effect structure is centered in the technology
is its feature of transparency to humans by instinct point of view. The
notion has been spreaded over wide application area such as quality control
energy management, and healthcare. Some experiments were conducted to prove
effectiveness of the technology in the article.
▲ ■ Development of an Automated DNA Detection System Using an Electrochemical
DNA Chip Technology
Toshiba Corp.・Sadato HONGO, Jun OKADA, Koji HASHIMOTO,
Toshiba Hokuto Electronics Corp・Koichi TSUJI,
Toshiba Corp・Masaru NIKAIDO and Nobuhiro GEMMA
A new compact automated DNA detection system GenelyzerTM has been developed.
After injecting a sample solution into a cassette with a built-in electrochemical
DNA chip, processes from hybridization reaction to detection and analysis
are all operated fully automatically. In order to detect a sample DNA,
electrical currents from electrodes due to an oxidization reaction of electrochemically
active intercalator molecules bound to hybridized DNAs are detected. The
intercalator is supplied as a reagent solution by a fluid supply unit of
the system. The feasibility test proved that the simultaneous typing of
six single nucleotide polymorphisms (SNPs) associated with a rheumatoid
arthritis (RA) was carried out within two hours and that all the results
were consistent with those by conventional typing methods. It is expected
that this system opens a new way to a DNA testing such as a test for infectious
diseases, a personalized medicine, a food inspection, a forensic application
and any other applications.
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