Abstract
〈Vol.5 No.5(2012.9)〉
Titles
[Contributed Papers]
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■ Doppler Positioning with a Movable Receiver Antenna for High-Accuracy
IMES Localization
Waseda University・Yoshihiro Sakamoto, The University of Tokyo・Takuji
Ebinuma,
Hitachi Industrial Equipment Systems Co., Ltd.・Kenjirou Fujii, and Waseda
University・Shigeki Sugano
A method for dramatically improving positioning accuracy of an indoor messaging
system (IMES), whose accuracy is normally 10.20 m, was developed. This
method uses Doppler shifts (produced by moving a receiver antenna) and
three-dimensional attitude of the receiver to determine the receiver’s
position. Since trilateration is not used, positioning is possible even
if the number of visible IMES transmitters is only one. A rotation-type
Doppler-measurement system applying this method was developed. To evaluate
the system, two experiments were conducted: in one, the rotation radius
of a movable receiver antenna was varied; in the other, the position where
positioning is conducted was varied. The experimental results show that
the method can achieve centimeter- to decimeter-level positioning accuracy.
As for design reference for setting up an IMES, the initial value of the
non-linear least squares that converges to a proper solution was determined,
and the influence of magnetic-declination error for the proposed positioning
method was analyzed.
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■ A New Air-fuel Ratio Control for A High-efficiency and Low-emission Engine
Honda R&D Co., Ltd.・Yuji Yasui，Ikue Kawasumiand Kosuke Higashitani
Accurate air-fuel ratio control is one of the subjects of low-emission
technologies for gasoline engines, and can maximize the conversion efficiency
of a three-way catalyst by controlling the air-fuel ratio of combustion
gas to an optimal target value. The engine equipped with a continuously
variable lift and phase mechanism has been introduced to improve fuel consumption.
However, it indicates large part-to-part variation and aging effect in
regard to the suction air amount in each combustion chamber, and the control
accuracy of the air-fuel ratio of the engine is significantly lower than
that of conventional gasoline engines. Conventional control methods using
feedback algorithms do not realize sufficient control accuracy of air-fuel
ratio control under transient phase. Therefore, a control system composed
of an adaptive feedforward algorithm as well as a feedback algorithm was
newly designed and applied to the engine.
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■ Passivity-based Visual Motion Observer Integrating Three Dimensional
Taraget Motion Models
Tokyo Institute of Technology・Takeshi HATANAKA and Masayuki FUJITA
This paper investigates a vision-based 3D rigid-body motion estimation
problem. In one of our previous works, the authors addressed the problem
using no prior information on the target motion. On the other hand, this
paper presents another approach assuming some target motion patterns. The
authors first consider a constant velocity model, which is a typical choice
of motion patterns, and present a novel motion observer integrating the
motion model. It is then proved based on passivity that the presented observer
leads both of the estimates of the target object pose and body velocity
to their actual values. Moreover, the result is extended to a more general
motion pattern. Finally, the effectiveness of the presented estimation
mechanism is demonstrated through experiments.
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■ Design of Compensators to Relocate Sampling Zeros of Digital Control
Systems for DC Motors
Chubu University・Takuya Sogo and Masafumi Joe
This paper presents a design method for a pre-filter for relocating sampling
zeros based on the Taylor expansion, which was recently found to be reduced
to a simple formula for a relative degree of 2. The method is successfully
applied to sampled-data systems of a DC motor, which usually has a sampling
zero near .1 that makes it difficult to apply feedforward control based
on pole-zero cancellation. The authors experimentally demonstrate that
the discrete-time model following controller works well and is free from
oscillations or ringing for sampled-data systems of a DC motor
when the proposed zero-relocation filter is implemented as an analog circuit
for an operational amplifier connected to a power amplifier. The authors
also experimentally demonstrate that an analog filter can be replaced by
a fast digital filter.
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■ A Clustering Method for Web Mining Based on Probabilistic Latent Semantic
Indexing
Waseda University・Jianxiong YANG and Junzo WATADA
Exploring an intranet or internet database enables us to discover useful
knowledge. In this process, a search engine plays a pivotal role. To this
end, various search engines have been proposed to heighten information
accuracy by exploiting key content relations in semantic web resources.
But a general-purpose search engine always includes useless or irrelevant
web pages in the search results. The next generation of web architecture,
known as SemanticWeb, can build a layered architecture to possibly mitigate
this deficiency by decreasing the noisy data in a searched result. The
objective of this paper is to propose a Probabilistic Latent Semantic Indexing
(PLSI) method used in semantic web search engines. The method can better
return appropriate information for user queries; in particular, a novel
ranking strategy is provided to measure the relevance score of an annotated
set of web results by considering user queries, data annotation, and the
underlying ontology.
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■ Operator-Based Robust Nonlinear Control for A Manipulator with Human
Multi-Joint Arm-Like Viscoelastic Properties
Tokyo University of Agriculture and Technology・Aihui WANG and Mingcong
DENG
In this paper, operator-based robust nonlinear tracking control for a manipulator
with human multi-joint armlike viscoelastic properties is considered by
using the robust right coprime factorization approach and a forward compensation
operator. First, an operator controller based on real measured data from
human multi-joint arm viscoelasticity is designed to obtain a desired motion
mechanism, the forward compensation operator is presented to compensate
the term related to the effect of the central nervous system (CNS), and
a nonlinear feedback control scheme is proposed to
eliminate effect of the uncertain plant. Second, the robust stability of
the present control system is discussed, and the performance of output
tracking is realized. Finally, the effectiveness of the proposed method
is confirmed by the simulation results based on experimental data.
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■ Online Leader-Following Formation Navigation with Initial Movements
of Followers and Its Experimental Verification
The University of Electro-Communications・Manabu SUZUKI，
Tottori University・Kazunori SAKURAMA and
The University of Electro-Communications・Kazushi NAKANO
This paper deals the leader-following formation navigation (LFFN), which
is one of the most important issues in formation control. In this formation,
one leader is controlled by a human operator, while multiple followers
pass along the leader’s trajectory in the same motion as the leader.
The followers move along the leader’s path behind the leader after some
intervals. Thus, around the initial time, the followers cannot determine
routes to track because there is no leader’s path before the initial
time. Moreover, if the followers try to mimic the motion of the leader
completely, they have to stop at the initial position of the leader. This
paper discusses how the followers should move around the initial time in order
to start up naturally and to achieve the LFFN afterwards. Comparing to
the authors’ previous method, these desired followers’ velocities can
be designed online, and an experiment with three mobile robots demonstrates
the effectiveness of the presented method.
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■ Fault-Tolerant Control for LPV Systems Based on Fault Compensator
LG Electronics・Jee-Hun PARK，Kyoto University・Shun-ichi AZUMA and Toshiharu SUGIE
This paper proposes a fault-tolerant control (FTC) scheme for polytopic
linear parameter varying (LPV) systems. First, a fault compensator is
proposed. Its structure is simple, but it is effective against actuator
faults. Then,in order to show its basic idea, the authors consider a state
feedback FTC scheme based on the fault compensator. Next,the FTC algorithm
is extended to an output feedback FTC scheme. The FTC scheme for LPV systems
involves a fault compensator based on the estimated fault and an observer
based on linear matrix inequality (LMI). The proposed FTC method is applicable
to a variety of systems and guarantees bounded states of the system in
the event of actuator faults. Numerical examples are given to demonstrate
its effectiveness.
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