All issues
Volume 46, Issue 6
Displaying 1-6 of 6 articles from this issue
- |<
- <
- 1
- >
- >|
Paper
Measurement
-
Kazuaki YAMAZAWA, Kiyoshi ANSO, Jun TAMBA, Masaru ARAI2010 Volume 46 Issue 6 Pages 309-316
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSPlatinum resistance thermometers (PRTs) are widely used in precise temperature measurements in scientific and industrial applications. The majority of the sensors used are Pt100 sensors under the JIS (Japan Industrial Standard). For more precise temperature measurements at the 0.01°C level, the thermometer should be calibrated by means of comparison measurements using a traceable standard thermometer with small uncertainties. This paper discusses the comparison method and its uncertainty for evaluating a thermometer that has similar characteristics with standard PRTs for the temperature range of 0°C∼30°C. We built a comparison bath, and evaluated that the uncertainty of the comparison measurement is as good as 0.43mK (k=2). Furthermore, as a demonstration of the comparison measurement using this equipment and method, we evaluated a small sized PRT of 1.2mm diameter and 10mm length, which fulfills the requirement for W (29.7646°C) of a standard PRT in ITS-90. The comparison results demonstrated the usefulness of the method as well as the usefulness of the evaluated PRT. This development enables quantitative evaluation of the characteristics of individual thermometers, and will provide useful data for the evaluation of uncertainties in temperature measurements.View full abstractDownload PDF (1060K)
Control
-
Hiroaki YAMAGUCHI, Masato MORI, Atsushi KAWAKAMI2010 Volume 46 Issue 6 Pages 317-326
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSThis paper presents a new type of coupled-vehicle system: a five-axle, three-steering coupled-vehicle system and its path following feedback control law. The coupled-vehicle system consists of two car-like mobile robots, two carriers and a steering system. One of the two car-like mobile robots is coupled by one of the two carriers via a revolute joint passively rotating and the other car-like mobile robot is also coupled by one remaining carrier via a passive revolute joint, and the two carriers are coupled via another passive revolute joint. The steering system is attached to one of the carriers and its steering axis is located at the same position of the rotating axis of the passive revolute joint coupling the two carriers. We first show that, by assuming virtual mechanical elements, it is possible to convert the kinematical equation of the coupled-vehicle system into three-chain, single-generator chained form in a coordinate system in which a path two times differentiable is an axis and a straight line perpendicular to the tangent of the path is another axis. Based on chained form, we secondly derive the path following feedback control law which enables the orientations of the two carriers relative to the tangent of the path to be controllable. By the feedback control law, it is possible to cause the two carriers to form a line-shaped composed carrier or a V-shaped composed carrier and to cause them to keep such shapes while performing a path following behavior, which means that the coupled-vehicle system is able to adapt the shape of the composed carrier to the shape of a transported object. The validity of the mechanical design of the coupled-vehicle system and its path following feedback control law has been verified experimentally.View full abstractDownload PDF (1580K) -
Hiroshi OKAJIMA, Nobutomo MATSUNAGA, Kenji SAWADA2010 Volume 46 Issue 6 Pages 327-335
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSThis paper proposes the design method of the dynamic quantizer for the networked control systems. It is well known that feedback type dynamic quantizer such as Delta/Sigma modulator is effective for quantization of data series and many methods for designing the dynamics have been proposed. When it is required to control with network communication, the data size of signal should be minimized appropriately by quantizers. Since the quantizing width of the quantizer concern with the data size, determination of quantizing width is important problem in networked control systems. However, the quantizing width has not been designed analytically in the past researches. In this paper, we propose the design method of the quantizing width based on the LMIs. The quantizing width would be determined explicitly with the communication rate constraints. By the proposed method, the quantizing width guarantee that the signals are quantized appropriately within the given data size. The effectiveness is illustrated by numerical examples.View full abstractDownload PDF (707K)
Systems and Information
-
Teturo ITAMI2010 Volume 46 Issue 6 Pages 336-345
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSQuantum tunneling that helps particles escape from local minima has been applied in “quantum annealing” method to global optimization of nonlinear functions. To control size of kinetic energy of quantum particles, we form a “quantum tunneling parameter” QT≡m/HR2, where HR corresponds to a physical constant h, Planck's constant divided by 2π, that determines the lowest eigenvalue of quantum particles with mass m. Assumptions on profiles of the function V(x) around its minimum point x0, harmonic oscillator type and square well type, make us possible to write down analytical formulae of the kinetic energy K in terms of QT. The formulae tell that we can make quantum expectation value of particle coordinates x approximate to the minimum point x0 in QT→∞. For systems where we have almost degenerate eigenvalues, examination working with our QT, that x→x0 in QT→∞, is analytically shown also efficient. Similar results that x→x0 under QT→∞ are also obtained when we utilize random-walk quantum Monte Carlo method to represent tunneling phenomena according to conventional quantum annealing.View full abstractDownload PDF (1035K)
System Integration
-
Masahito YASHIMA, Tasuku YAMAWAKI2010 Volume 46 Issue 6 Pages 346-352
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSThe present paper proposes the trajectory planning based on “the dynamics shaping” for a redundant robotic arm to hit a target robustly toward the desired direction, of which the concept is to shape the robot dynamics appropriately by changing its posture in order to achieve the robust motion. The positional error of the end-effector caused by unknown disturbances converges onto near the singular vector corresponding to its maximum singular value of the output controllability matrix of the robotic arm. Therefore, if we can control the direction of the singular vector by applying the dynamics shaping, we will be able to control the direction of the positional error of the end-effector caused by unknown disturbances. We propose a novel trajectory planning based on the dynamics shaping and verify numerically and experimentally that the robotic arm can robustly hit the target toward the desired direction with a simple open-loop control system even though the disturbance is applied.View full abstractDownload PDF (1696K)
Short Paper
-
Yu KAWANO, Toshiyuki OHTSUKA2010 Volume 46 Issue 6 Pages 353-355
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSThis paper considers global observability of input-affine polynomial systems. To test observability of nonlinear systems, distinguishability is often used. This criterion may consist of checking an infinite set of equations. In this paper, based on results from commutative algebra, we show a finite set of equations characterizes observability of the systems.View full abstractDownload PDF (172K)
- |<
- <
- 1
- >
- >|