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Volume 44, Issue 3
Displaying 1-11 of 11 articles from this issue
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Fumihiro SAKUMA, Laina MA2008 Volume 44 Issue 3 Pages 209-218
Published: March 31, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESS0.65μm and 0.9μm radiation thermometers are used as the standard thermometers at high temperatures. These radiation thermometers employ three to five ranges to cover their whole temperature ranges. The range ratios of these thermometers influence the calibration uncertainty. The measurement method, measured results and the long term stability of the range ratios are shown.View full abstractDownload PDF (5383K) -
Hiroaki KAJIKAWA, Tokihiko KOBATA, Akira OOIWA2008 Volume 44 Issue 3 Pages 219-226
Published: March 31, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSWe are developing a controlled-clearance pressure balance with the aim of upgrading the hydraulic high-pressure standard for pressures up to 1 GPa. This pressure balance is equipped with an automatic weight-loading unit; the total mass of the weights is about 1100 kg and each weight is loaded independently on the piston. In this study, as a preliminary step for the evaluation of the generated pressure, the masses of heavy weights are calibrated in situ using a digital mass comparator. To manipulate the heavy weights safely and precisely and to reduce the uncertainty of their masses, some auxiliary devices, such as hand-rotating jacks and a centering base, were introduced. The mass calibration was performed twice, in 2003 and 2006, and the results were compared with each other. The uncertainty of the mass in the latest calibration (2006) was reduced because the waiting time before data acquisition was set appropriately. The relative difference in the masses obtained in the two calibrations was less than 2 parts per million and the absolute value of the normalized error, En, was less than unity. Thus, it is confirmed that the weight set has been kept under suitable conditions and that the masses of the weights are sufficiently stable.View full abstractDownload PDF (8192K) -
Masato ISHIKAWA, Kenji YAMADA, Toshiharu SUGIE2008 Volume 44 Issue 3 Pages 227-233
Published: March 31, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn this paper, we deal with feedback control problem for a jumping robot based on energy-preserving feedback and iterative learning approach. In our previous research, we achieved periodic hopping motion control by keeping the total system energy to the reference value. But the resulting behavior of the robot was uniquely determined by the reference energy, and there was no room to modify the quality (such as peak height or landing impact) of the motion. In this research, we introduce three adjustable parameters which determines virtual compliance between the robot and the environment, and propose an on-line updating law for the parameters to realise accurate and robust control of the periodic behavior. Efficiency of the proposed method is validated both in simulations and experiments.View full abstractDownload PDF (4857K) -
Hiroto HOSHINA, Koji TSUMURA, Hideaki ISHII2008 Volume 44 Issue 3 Pages 234-242
Published: March 31, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn this paper, we consider to derive the coarsest memory-less quantizer which can stabilize a single-input discrete-time linear time-invariant system with stochastic packet losses in the sense of stochastic quadratic stability. We show that the upper bound of the coarseness is strictly given by the packet loss probability and the unstable poles of the plant. We furthermore deal with permissible dead-band width around the origin of the quantizers and time-varying finite quantizers in order to realize control using finite communication rate.View full abstractDownload PDF (4903K) -
Kenji FUJIMOTO, Sayaka ONO2008 Volume 44 Issue 3 Pages 243-251
Published: March 31, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn this paper, we propose a finite-dimensional approximation for a nonlinear infinite-dimensional system via balanced realization.The proposed method is accomplished by balanced realization and singular value analysis for nonlinear systems.This approach is expected to derive effective approximate models preserving particular input-output behavior.To obtain balanced realization for infinite-dimensional systems, a sufficient condition and a necessary one characterizing them are derived.Finally, the effectiveness of the method is shown by a numerical simulation.View full abstractDownload PDF (2092K) -
Naoya HATAKEYAMA, Akira SHIMADA2008 Volume 44 Issue 3 Pages 252-259
Published: March 31, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSWe propose a high-speed motion control technique for inverted pendulum robots that utilizes instability as a control factor. An inverted pendulum is a self-regulated system simulating a child's game of swaying an umbrella or a stick upwards. The controller design for pendulums has been widely been challenged since the 1970s. A two-wheeled, self-balancing electric transportation device using the inverted pendulum's control principle was developed in the US. Many biped walking robots have also made use of this principle. Essentially, inverted pendulums possess better control characteristics since they do not fold up. Shimada and Hatakeyama suggested an idea that was contrary to this basic principle. Their controller was designed to brake down its balance when in motion. This was done using zero dynamics derived by partial feedback linearization, in order to control the tilt angles of the robots. However, such robots can only move in a straight line. We introduce extended motion including revolving and curving by using a nonlinear control technique. We also present the simulation and experimental results.View full abstractDownload PDF (10275K) -
Hiroaki MUKAIDANI2008 Volume 44 Issue 3 Pages 260-268
Published: March 31, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSThis paper discusses the Nash gables for a class of uncertain weakly coupled large-scale systems. Particu-larly, the infinite horizon stochastic Nash games are addressed by considering uncertainty as state-dependent noise. First, the asymptotic structure for the solutions of the cross-coupled stochastic algebraic Riccati equations (CSAREs) and the condition for the existence of solutions are derived. Second, using such properties, an approx-imate Nash equilibrium strategy that is independent of the coupling parameter ε is established. Moreover, it is shown for the first time that the new strategy achieves O (ε2) approximation. Finally, in order to demonstrate the efficiency of the proposed design method, a numerical example is provided.View full abstractDownload PDF (4528K) -
Shun TAGUCHI, Shinkichi INAGAKI, Tatsuya SUZUKI, Soichiro HAYAKAWA, Ta ...2008 Volume 44 Issue 3 Pages 269-277
Published: March 31, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSThis paper presents the development of a mathematical model of the human decision making. The main contributions of this paper are introduction of the logistic regression model as the mathematical model of the decision, development of the real time prediction of the decision based on the model, and proposal of some useful quantified measures to evaluate the characteristics of the human behavior. The proposed modeling and analysis strategies are applied to the driving behavior, in particular, focusing on the turn-right task in the intersections. Furthermore, two quantified measures ‘decision entropy’ and ‘decision aggressiveness’ are defined based on the estimated parameters in the logistic regression model. The objective evaluation made by these measures agree well with the subjective evaluation made by the questionnairs.View full abstractDownload PDF (6226K) -
Application in Endovascular Coil EmbolizationYoshitaka NAGANO, Akihito SANO, Masamichi SAKAGUCHI, Hideo FUJIMOTO2008 Volume 44 Issue 3 Pages 278-284
Published: March 31, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSRecently, minimally invasive surgery with catheter became popular. We have developed a novel force sensor for actual extra-fine and long medical wires which can be used in endovascular coil embolization. The sensory principle is based on optically measuring the wire bending when compressive force is applied. The same sensor permits use of wires with different stiffness. The proposed force sensor is unified with Y-connector, which makes it compatible with medical equipment, and can be used in surgery. Furthermore, this sensor has no bad influence on the surgeon's skillful operation and his/her haptic sense. In this paper, basic characteristics of experimental force sensor prototype are examined and its validity is confirmed by an experiment of coil embolization.View full abstractDownload PDF (15001K) -
Jun YONEYAMA2008 Volume 44 Issue 3 Pages 285-287
Published: March 31, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSThis paper discusses H∞ disturbance attenuation for a class of discrete-time systems with time varying delays. We develop a less conservative condition that guarantees the H∞ disturbance attenuation for such a system.View full abstractDownload PDF (367K) -
Masato ISHIKAWA, Ichiro MARUTA, Toshiharu SUGIE2008 Volume 44 Issue 3 Pages 288-290
Published: March 31, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn this paper, we propose an extended use of feedback modulator for discrete-valued input control systems with typical actuator nonlinearity, such as delayed switching, deadzone and delayed backlash. We examine the proposed method by numerical simulations, to show that the influence of the nonlinearities are effectively reduced, as well as its robustness against the uncertainty of the nonlinearity models.View full abstractDownload PDF (477K)
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