Abstract
〈Vol.3 No.5(2010.9)〉
Titles
[Contributed Papers]
▲
■ Estimation of Continuous-time Nonlinear Systems by using the Unscented
Kalman Filter
University of Tokushima・Min ZHENG, Kenji IKEDA, and Takao SHIMOMURA
This paper proposes a continuous-time model estimation method by using the Unscented Kalman Filter (UKF) from the sampled I/O data, in which the plant parameters as well as the initial state are estimated. The initial state is estimated based on a backward system of the plant, and the parameters are estimated by using the iterated UKF, which repeats the estimation of the forward system and the backward system alternately. In order to demonstrate the effectiveness of the proposed method, the rotary pendulum is considered to estimate the parameters of the continuous-time nonlinear system.
▲
■ Measurement of the Diameters of Deformed Bars in Concrete Using an Electromagnetic
Wave Radar(in the Presence of Cross Bars)
Yamaguchi University・Shogo TANAKA and Halima BEGUM
The authors previously proposed a method to measure the diameter of the deformed reinforcing bars in concrete structures nondestructively using an electromagnetic wave radar. The method estimates the periodicity of the knots of the inspected bar and utilized the standard relationship between the knot's pitch and the diameter of the bar to measure the diameter indirectly. The effectiveness of the method was verified using test specimens where the bars were placed parallel to each other. However, in practical case, where other reinforcing bars cross the inspected bar perpendicularly, the stronger reflections from the cross bars influence the reflection from the inspected bar. The paper thus proposes a general method which eliminates such unwanted influences from the cross bars and measures the diameter accurately even in practical environment.
▲
■ Experimental Study on Microassembly by Using Liquid Surface Tension
Saitama University・Yasuhiro KATO, Takeshi MIZUNO,
Hiroshi TAKAGI, Yuji ISHINO, and Masaya TAKASAKI
This research studies the use of a water drop to pick up a minute object for manufacturing small electric devices. The method can align the center of an object with the center of the nozzle even if there is a deflection between them initially. This is called a self-centering effect. The relationship between the size of the water drop and the parameters of storing water in the nozzle is studied experimentally. The time for drawing water into the nozzle and the pressure provided to the nozzle are investigated as parameters, and the conditions in which the formed drops become hemispherical are clarified. To prove the feasibility and efficacy of the proposed process using a hemispherical drop, experiments on picking up a resistor chip and spherical and cylindrical objects are carried out. The self-centering effect is investigated by varying the deflection of an object from the center of the nozzle. It is also confirmed that the self-centering effect leads to virtually zero deflection remaining after the object is picked up.
▲
■ Efficient Pruning of Class Association Rules using Statistics and Genetic Relation Algorithm
Waseda University・Eloy GONZALES, Shingo MABU,
Karla TABOADA, Kaoru SHIMADA, and Kotaro HIRASAWA
Association rule mining is one of the most exploited areas in data mining, which includes applications from business to data classification and summarization. Thus, several association rule-based classification methods have been proposed. Most of them often produce too many rules for humans to read over, that is, the generated rules are usually complex and hardly understandable for the users. Only some of the rules extracted are of real interest. Most of the rules are either redundant, irrelevant or obvious.
In this paper, a new post-processing method for pruning class association rules is proposed by a combination of statistics and an evolutionary method named Genetic Relation Algorithm (GRA). The algorithm is carried out in two phases. In the first phase, the rules are pruned depending on their matching degree with data and in the second phase, GRA selects the most interesting rules using the distance between them.
The two-phase method has the following properties: 1) efficient since reduces dramatically the pruning processing time. 2) reliable because a small rule set is produced which is accurate (it keeps at least the same prediction accuracy as the original large rule set), comprehensible (it is more understandable for the users since the number of attributes involved in the rule is also small) and interesting because of the diversity of rules.
The advantages of the proposed method is demonstrated using several real datasets and it is compared with other conventional methods including GNP-based mining in terms of prediction accuracy and time consumption.
▲
■ Proposal and Fundamental Properties of Parallel Electrostatic Suspension
Systems
Saitama University・Takeshi MIZUNO, Takaaki KATO, and Masaya TAKASAKI
Parallel electrostatic suspension is proposed and studied analytically.
In this suspension system, a single power amplifier is operated to suspend
multiple floators or to control the multiple-degree-of-freedom motions
of a floator. Parallel suspension systems are classified into two types
according to the connection of electrodes for suspension: parallel-connected
and series-connected. The controllability of the former type is discussed
both for direct and indirect voltage controlled systems. The conditions
for each system to be controllable are clarified. It is also shown that
the latter type becomes uncontrollable.
▲
■ Modified Multi-Objective Particle Swarm Optimization: Application on Optimization of Diesel Engine Control Parameter
Waseda University・Dongmei WU, Masatoshi OGAWA,
Yasumasa SUZUKI, Harutoshi OGAI, and Jin KUSAKA
In this paper, optimization of diesel engine control parameter using a modified multi-objective particle swarm optimization (MOPSO) is proposed. This problem is formulized as a multi-objective optimization problem involving three optimization objectives: brake specific fuel consumption (BSFC), exhaust gas emission, and soot. A modified MOPSO is proposed with integration of particle swarm optimization (PSO) and crossover approach. Several benchmark functions are tested, and results reveal that the modified MOPSO is more efficient than the typical MOPSO. Engine control parameter optimization with an extended PSO and the modified MOPSO is simulated, respectively. It proved the potential of the modified MOPSO for engine control parameter optimization problem.
▲ ■ Seamless Control of Multi-fingered Robot Hands based on Grasp Polyhedrons
Wakayama University・Kenji NAGASE,
Kawasaki Heavy Industries・Satoshi SHIRAI,
and Wakayama Univ.・Tsuyoshi HAYASHI
This paper is concerned with a new feedback control design methodology
for multi-fingered robot hands applicable to multiple contact situations.
As a first step, we especially concern with the situations where all the
fingers are in contact or not in contact to the object, Considering the
tasks of catching and releasing the object preceding to or followed by
grasping/manipulating the object. Main features of the proposed method
are: (1) The direction of the fingertip motion in the non-contact situation
is selected to be directly linked to the direction of the object motion
and the internal force in the contact situation; (2) By introducing a unified
system description for multiple contact situations, a linearizing compensator
applicable to multiple contact situations is designed. The controller can
handle the tasks with the multiple contact situations by choosing appropriate
desired trajectories for the linearizing compensator without switching
control architecture. In addition, owing to the selection of the motion
in the non-contact situation, all the fingers can approach to the object
synchronously along the directions of the object motion and the internal
force in the contact situation. A numerical example is shown to prove effectiveness
of the proposed method.
▲
■ Stability of Switched Stochastic Systems in Discrete-Time
Hirosaki University・Yasushi IWATANI,
Tohoku University・Shogo ARAI, and Koichi HASHIMOTO
This paper considers the stability problem of stochastic and discrete-time switched systems with arbitrary switching. Several stability conditions based on Lyapunov theory are presented. In particular, a common Lyapunov function approach and a multiple Lyapunov function approach are discussed. For linear switched systems, a tractable stability test is given in terms of linear matrix inequalities.
▲
■ Model Predictive Controller with a Fixed Compensator for an Electromagnetic Valve
Kyushu University・Addy WAHYUDIE, Nippon Steel Engineering・Taizo NAKAO,
Kyushu University・Toshimitsu KAI, Kansai Electric Power Corporation・Suguru
SEIKOBA,
Kyushu University・Masakazu MUKAI, and Taketoshi KAWABE
This paper presents a model predictive controller for an electromechanical
valve. The proposed method has an important feature that it is a deadbeat
controller with a designed traveling time of the valve armature. Therefore,
the armature reaches a target position and velocity. The controller calculates
optimum control force for the system in each sampling instant. A two-point
boundary problem is solved analytically for calculating the optimal force
for the system. A disturbance observer is used for estimating the armature
velocity and for improving the controlled system robustness against parameter
uncertainty. The proposed method is demonstrated in computer simulation,
and on an experimental testbed.
▲
■ Adaptive Feedback Stabilization for a Class of Cascaded Nonlinear Systems with Discontinuous Connection
Toyota Central R&D Laboratories・Maiko HIRANO,
Sophia University ・Tielong SHEN, and Katsutoshi TAMURA
This paper investigates an adaptive control problem for a class of cascaded nonlinear systems with discontinuity. The uncertainty is taken into account as an unknown parameter and bounded unknown functions in the differential equation with discontinuous right hand side. The Filippov-framework is used to analyze the behavior of the discontinuous dynamical systems. First, a state feedback design with parameter adaptation is presented, where the designed controller ensures the convergence of the closed loop system to any given bounded set. Then, the design approach is extended to achieve the asymptotical stability under a stronger condition on the driven subsystem. Finally, a numerical example is given to demonstrate the proposed design approach.
▲
■ A Matrix-Dilation Approach to Robust Semidefinite Programming and Its
Error Bound
Nanzan University・Yasuaki OISHI
An asymptotically exact approach is presented for robust semidefinite programming, where coefficient matrices polynomially depend on uncertain parameters. Since a robust semidefinite programming problem is difficult to solve directly, an approximate problem is constructed based on a division of the parameter region. The optimal value of the approximate problem converges to that of the original problem as the resolution of the division becomes higher. An advantage of this approach is that an upper bound on the approximation error is available before solving the approximate problem. This bound shows how the approximation error depends on the resolution of the division. Furthermore, it leads to construction of an efficient division that attains small approximation error with low computational cost. Numerical examples show efficacy of the present approach. In particular, an exact optimal value is often found with a division of finite resolution.
▲
■ Fault-Tolerant Control Synthesis against Partial Actuator Faults based on the Constrained Particle Swarm Optimization
Kyoto University・Jee-Hun PARK and Toshiharu SUGIE
This paper proposes a fault-tolerant control (FTC) synthesis against partial
actuator faults through particle swarm optimization (PSO). It is shown
how to design a reconfigurable state feedback controller in such a way
that the performance deterioration stays within the prescribed tolerance
when the actuator faults occur. The proposed FTC method is applicable for
a variety of linear systems with input constraints. Numerical examples
subject to input constraints are given to demonstrate its effectiveness.
|
