Abstract
〈Vol.4 No.4(2011.7〉
Titles
[Contributed Papers]
▲
■ Design of a Hierarchical System Using PID Control with an Intelligent
Sequence Controller and Its Application to Ethylene Plants in Unsteady
State
Idemitsu Kosan Co., Ltd.・Tetsuji TANI and Takeshi TAKEUCHI
A hierarchical system is developed that consists of an intelligent sequence
controller and a PID controller,where the intelligent sequence controller
supervises the PID controller. In other words, the intelligent sequence
controller plays the role of a well-experienced operator and mimics the
operator’s procedures. In an ethylene plant, the decoking operation of
the cracking furnace makes the ethylene plant highly unstable. We apply
this hierarchical system to the decoking process in an ethylene plant in
order to demonstrate its effectiveness. As a result, the number of operational
interventions in the decoking process is reduced by 95%, and the levels
of the towers and the overhead temperatures of
the towers can be satisfactorily stabilized during the decoking process.
▲
■ Improvements in Accurate GPS Positioning Using Time Series Analysis
Keio University・Yuichiro KOYAMA and Toshiyuki TANAKA
Although the Global Positioning System (GPS) is used widely in car navigation
systems, cell phones, surveying,and other areas, several issues still exist.
We focus on the continuous data received in public use of GPS, and propose
a new positioning algorithm that uses time series analysis. By fitting
an autoregressive model to the time series model of the pseudorange, we
propose an appropriate state-space model. We apply the Kalman filter to
the state-space model and use the pseudorange estimated by the filter in
our positioning calculations. The results of the authors’ positioning
experiment show that the accuracy of the proposed method is much better
than that of the standard method. In addition,as we can obtain valid values
estimated by time series analysis using the state-space model, the proposed
state-space model can be applied to several other fields.
▲
■ Torque Control for Automotive Engines with Variable Valves via Air and
Burned Gas Flow-Based Design
Toyota Central R&D Labs., Inc.・Tomohiko JIMBO and
Nagoya University・Yoshikazu HAYAKAWA
This paper proposes a predictive control method for automotive engines
with variable valves. The control purpose is to track not only the torque
reference but also the pressure reference of the surge tank in consideration
for the constraint of internal exhaust gas recirculation ratio. The control
inputs are the throttle angle and the intake valve lift, however, the proposed
control method is based on a flow model where the mass flows through the
throttle and the intake valves are regarded as the virtual control inputs.
The controller designed for the SICE benchmark engine is validated by
numerical simulations.
▲
■ Optimal Linear Quadratic Regulators for Control of Nonlinear Mechanical
Systems with Redundant Degrees-of-Freedom
Ritsumeikan University・Suguru ARIMOTO
An optimal regulator problem for endpoint position control of a robot arm
with (or without) redundancy in its total degrees-of-freedom (DOF) is solved
by combining Riemannian geometry with nonlinear control theory. Given a
target point, within the task-space, that the arm endpoint should reach,
a task-space position feedback with joint damping is shown to asymptotically
stabilize reaching movements even if the number of DOF of the arm is greater
than the dimension of the task space and thereby the inverse kinematics
is ill-posed. Usually the speed of convergence of the endpoint trajectory
is unsatisfactory, depending on the choice of feedback gains for joint
damping. Hence, to speed up the convergence without incurring further energy
consumption, an optimal control design for minimizing a performance index
composed of an integral of joint dissipation energy plus a linear quadratic
form of the task-space control input and output is introduced. It is then
shown that the Hamilton-Jacobi-Bellman equation derived from the principle
of optimality is solvable in control variables and the Hamilton-Jacobi
equation itself has an explicit solution. Although the state of
the original dynamics (the Euler-Lagrange equation) with DOF-redundancy
contains uncontrollable and unobservable manifolds, the dynamics satisfies
a nonlinear version of the Kalman-Yakubovich-Popov lemma and the task-space
inputoutput passivity. An inverse problem of optimal regulator design for
robotic arms under the effect of gravity is also tackled by combining Riemannian
geometry with passivity-based control theory.
▲
■ Analysis of Various Interestingness Measures in Class Association Rule
Mining
Waseda University.・Xianneng LI，Shingo MABU，Huiyu ZHOU，
Kaoru SHIMADA，and Kotaro HIRASAWA
Many measures have been developed to determine the interestingness of rules
in data mining. Numerous studies have shown that the effects of different
measures depend on the concrete problems, and different measures usually
provide different and conflicting results. Therefore, selecting the appropriate
measure becomes an important issue in data mining. In this paper, a novel
approach to select the appropriate measure for class association rule mining
is proposed. The proposed approach is applied to several problems, including
benchmark and real-world datasets. The experimental results show that the
proposed approach is a powerful tool to analyze various measures to select
the right ones for the concrete problems, leading to the increase of the
classification accuracy. Based on the study, this paper further proposes
four properties of interestingness measures that should be considered in
class association rule mining.
▲
■ Robust Adaptive Position/Force Control of Mobile Manipulators: Theory
and Experiments
Toyota Technological Institute・Tatsuo NARIKIYO，Michihiro KAWANISHI，
Tomohito MIZUNO，and Yasuo HANADA
Mobile manipulators are expected to play an important role in production
processes of factories and in medical care systems of welfare business.
To come up to this expectation, a mobile manipulator is required to simultaneously
track both the desired position trajectory and force trajectory. Therefore
the authors have proposed two adaptive hybrid position/force control schemes
for mobile manipulators. In this paper we implement these control schemes
in an actual mobile manipulator and demonstrate the effectiveness of these
proposed control schemes experimentally.
|
