The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform

Shigeo Hirose - One of the best experts on this subject based on the ideXlab platform.

  • ICRA - Shape memory alloy servo actuator system with Electric Resistance feedback and application for active endoscope
    Proceedings. 1988 IEEE International Conference on Robotics and Automation, 1
    Co-Authors: Kentarou Ikuta, Masahiro Tsukamoto, Shigeo Hirose
    Abstract:

    A control system for a shape memory alloy (SMA) servo actuator, and its application to a unique medical tool, are considered. It is thought that the Electric Resistance value of an SMA can be utilized to monitor the transformation of the SMA directly. Therefore, an antagonistic transformation control scheme using Electric Resistance feedback is proposed and is verified by several experiments. This control scheme reduces the open-loop hysteresis of an SMA actuator and improves greatly its robustness against heat disturbance due to changes in the cooling condition. Research into the application of the method in an active endoscope is reported. It consists of five segments of 13 mm diameter, 40 mm length each. The bending angle of each segment can be controlled individually from outside by using antagonistic Electric Resistance feedback without any motion sensors. A model for smooth insertion to the colon is verified. >

Kentarou Ikuta - One of the best experts on this subject based on the ideXlab platform.

  • ICRA - Shape memory alloy servo actuator system with Electric Resistance feedback and application for active endoscope
    Proceedings. 1988 IEEE International Conference on Robotics and Automation, 1
    Co-Authors: Kentarou Ikuta, Masahiro Tsukamoto, Shigeo Hirose
    Abstract:

    A control system for a shape memory alloy (SMA) servo actuator, and its application to a unique medical tool, are considered. It is thought that the Electric Resistance value of an SMA can be utilized to monitor the transformation of the SMA directly. Therefore, an antagonistic transformation control scheme using Electric Resistance feedback is proposed and is verified by several experiments. This control scheme reduces the open-loop hysteresis of an SMA actuator and improves greatly its robustness against heat disturbance due to changes in the cooling condition. Research into the application of the method in an active endoscope is reported. It consists of five segments of 13 mm diameter, 40 mm length each. The bending angle of each segment can be controlled individually from outside by using antagonistic Electric Resistance feedback without any motion sensors. A model for smooth insertion to the colon is verified. >

Norio Tsubokawa - One of the best experts on this subject based on the ideXlab platform.

  • A novel contamination sensor in solution: the response of the Electric Resistance of a composite based on crystalline polymer-grafted carbon black
    Sensors and Actuators B-chemical, 2001
    Co-Authors: Norio Tsubokawa, M Tsuchida, J Chen, Y Nakazawa
    Abstract:

    Abstract The response of the Electric Resistance of the composite prepared from crystalline polymer-grafted carbon black as a function of the contamination in solution was investigated. The Electric Resistance of the composite prepared from poly(e-caprolactone) (PCL)-grafted carbon black drastically increased in hexane, containing chloroform, trichloroethane, and ethanol and returned immediately to the initial Resistance when it was transferred into pure hexane. The response of the Electric Resistance was highly reproducible. The logarithm of Electric Resistance was linearly proportional to the concentration of chloroform in hexane. Furthermore, the Electric Resistance of the composite prepared from crystalline poly(ethylene glycol) (PEG)-grafted and poly(ethylene adipate) (PEA)-grafted carbon black also drastically increased in hexane containing alcohol, which is a good solvent of the grafted chain (PEG and PEA). This is due to a widening of the gaps between the carbon black particles based on the absorption of solvent for these crystalline polymers.

  • Responsiveness of Electric Resistance of polymer-grafted carbon black/alumina gel composite against solvent vapor and solute in solution
    Polymer Bulletin, 2000
    Co-Authors: Norio Tsubokawa, Junya Inaba, Katsunori Arai, Kazuhiro Fujiki
    Abstract:

    The carbon black/alumina gel composites were prepared by sol-gel reaction of aluminum isopropoxide in the presence of polymer-grafted carbon black. The Electric Resistance of the alumina gel composite from polymer-grafted carbon black was very sensitive to vapor of good solvent for grafted polymer on carbon black: the Electric Resistance of the alumina gel composite suddenly decreased in solvent vapor and returned to initial Resistance when it was transferred into dry air. The effect of surface area and particle size of carbon black on the responsiveness was also investigated. In addition, the Electric Resistance of the alumina gel composite was found to respond to water and methanol in n-hexane and diethyl ether.

  • A Novel Gas Sensor from Poly(ethylene glycol)-Grafted Carbon Black. Responsibility of Electric Resistance of Poly(ethylene glycol)- Grafted Carbon Black against Humidity and Solvent Vapor
    Polymer Journal, 1999
    Co-Authors: Masaki Okazaki, M Tsuchida, Kiyotaka Maruyama, Norio Tsubokawa
    Abstract:

    Poly(ethylene glycol) (PEG) having different molecular weight was successfully grafted onto carbon black surface by direct condensation of terminal hydroxyl groups of PEG with carboxyl groups on the surface using N , N ′-dicyclohexylcarbodiimide as a condensing agent. The Electric Resistance of a composite prepared from PEG and PEG-grafted carbon black drastically increased to 10^3–10^4 times of initial Resistance in humidity and vapor of methanol, and ethanol, which are good solvent of PEG, and returned immediately to initial Resistance when it was transferred in dry air. But the change of Electric Resistance of the composite was hardly observed in hexane and toluene vapor, which are poor solvent of PEG. The logarithm of Electric Resistance is linearly proportional to relative humidity. The sensitivity of Electric Resistance decreased with increasing molecular weight of PEG. In addition, the Electric Resistance of the composite from PEG-grafted carbon black lost the responsibility against solvent vapor above melting point of PEG. By crosslinking of the composite from PEG-grafted carbon black with triisocyanate, the responsibility against solvent vapor disappeared completely. These results indicated that the crystalline structure of PEG plays an important role on the responsibility of Electric Resistance of PEG-grafted carbon blacks against humidity and alcohol vapor.

  • Responsibility of Electric Resistance of polyethyleneimine-grafted carbon black against alcohol vapor and humidity
    Polymer Bulletin, 1997
    Co-Authors: Norio Tsubokawa, Sachio Yoshikawa, Kiyotaka Maruyama, Tomoaki Ogasawara, Kazuhiro Saitoh
    Abstract:

    Crystalline polyethyleneimine (PEI(C)) was successfully grafted onto carbon black surface by direct condensation of imino groups of PEI with carboxyl groups on the surface using N,N′-dicyclohexylcarbodiimide as a condensing agent. The Electric Resistance of a composite prepared from PEI(C) and PEI(C)-grafted carbon black drastically increased to 103–104 times of initial Resistance in methanol, ethanol, and water vapor. But the change of Electric Resistance of the composite hardly observed in hexane and toluene vapor. These results suggest the possibility of detection of a slight change of crystalline structure of PEI by the absorption of solvent as a large increase of Electric Resistance of the composite.

Masahiro Tsukamoto - One of the best experts on this subject based on the ideXlab platform.

  • ICRA - Shape memory alloy servo actuator system with Electric Resistance feedback and application for active endoscope
    Proceedings. 1988 IEEE International Conference on Robotics and Automation, 1
    Co-Authors: Kentarou Ikuta, Masahiro Tsukamoto, Shigeo Hirose
    Abstract:

    A control system for a shape memory alloy (SMA) servo actuator, and its application to a unique medical tool, are considered. It is thought that the Electric Resistance value of an SMA can be utilized to monitor the transformation of the SMA directly. Therefore, an antagonistic transformation control scheme using Electric Resistance feedback is proposed and is verified by several experiments. This control scheme reduces the open-loop hysteresis of an SMA actuator and improves greatly its robustness against heat disturbance due to changes in the cooling condition. Research into the application of the method in an active endoscope is reported. It consists of five segments of 13 mm diameter, 40 mm length each. The bending angle of each segment can be controlled individually from outside by using antagonistic Electric Resistance feedback without any motion sensors. A model for smooth insertion to the colon is verified. >

Akira Todoroki - One of the best experts on this subject based on the ideXlab platform.

  • Detectability of Bearing Failure of Composite Bolted Joints by Electric Resistance Change Method
    Key Engineering Materials, 2006
    Co-Authors: Yoshinobu Shimamura, Akira Todoroki, Keiko Oda, Masahito Ueda
    Abstract:

    Bolted joints are widely used for composite structures. As is well known, excessive bearing load gives rise to bearing failure at hole boundaries. Detecting bearing failure is important for assuring integrity of composite structures. Since conventional nondestructive inspection methods are expensive, cumbersome, time-consuming, and not suitable for health monitoring, a simple, low-cost inspection method for bearing failure must be developed. Authors have demonstrated the feasibility of detecting bearing failure by using an Electric Resistance change method. In this study, more detailed analyses were carried out to investigate the detectability in terms of the damage size and the distance between damage and electrodes. The results show that bearing failure of less than 10mm square causes the Electric Resistance change of a few hundred ppm and thus can be easily detected, and that the electrodes can be mounted more than 10 mm far from a bolt hole.

  • Wireless Strain Monitoring of CFRP Laminates Using Electric Resistance Change with Oscillating Circuit
    Key Engineering Materials, 2006
    Co-Authors: Roysuke Matsuzaki, Akira Todoroki
    Abstract:

    To identify a delamination crack in a CFRP laminate wirelessly, we proposed an Electric Resistance change method with oscillating circuit in the previous study. Although the method detects the delamination creation, it cannot monitor condition of applied strain before delamination creation because the Electric Resistance change due to strain changing is quite small. In the present study, a bridge circuit, two amplifiers and voltage-controlled oscillator are added to sensing circuit so that it can monitor very little change of the Electric Resistance change. Using proposed strain sensing system, the Electric Resistance change and oscillating frequency change due to strain changing are experimentally measured. As a result, the method is found to successfully monitor the applied strain.

  • Application of Electric Resistance Change Method to Damage Detection of CFRP Bolted Joints
    Key Engineering Materials, 2005
    Co-Authors: Yoshinobu Shimamura, Akira Todoroki, Keiko Oda, Hideo Kobayashi, Takaomi Inada
    Abstract:

    Bolted joints are widely used for composite structures. As is well known, excessive bearing load gives rise to bearing failure at hole boundaries. Detecting bearing failure is important for assuring integrity of composite structures. Conventional nondestructive inspection methods are expensive, cumbersome, time-consuming, and not suitable for health monitoring, and a simple, low-cost inspection method for bearing failure must be developed. Authors have experimentally demonstrated detection bearing failure by an Electrical Resistance change method. In this study, detectablity of remote damage, which includes bearing failure, using an Electric Resistance change method is investigated analytically. The results show that fiber breaking and delamination induce permanent increase in the Electric Resistance of the bolted composite joints, and that the proposed method, which involves measuring Electric Resistance, is effective for detecting bearing failure.

  • analysis of the effect of the configuration of the delamination crack on delamination monitoring with Electric Resistance change method
    Journal of the Japan Society for Composite Materials, 2003
    Co-Authors: Akira Todoroki, Miho Tanaka, Yoshinobu Shimamura, Hideo Kobayashi
    Abstract:

    Since delaminations of composite laminates are usually invisible or difficult to be detected by visual inspections, the delamination causes low reliability of primary structures. In order to improve the low reliability, automatic systems for delamination identifications in-service are desired. The present study employs an Electric Resistance change method for detections of the delaminations. Although the method is effective to monitor the delamination cracks, the method requires many experiments to solve inverse problems. Since the experiment cost is high, an analytical method for preparation of the data sets of the Electric Resistance changes is desired. In practical delamination, however, usually includes a matrix cracking. In the present study, therefore, the effect of the matrix cracking on the Electric Resistance changes between the electrodes is investigated with FEM analyses. As a result, it can be concluded that the simple calculations using a straight delamination crack model are enough for obtaining the data set of Electric Resistance changes to calculate the response surfaces.

  • delamination monitoring of graphite epoxy laminated composite plate of Electric Resistance change method
    Composites Science and Technology, 2002
    Co-Authors: Akira Todoroki, Yuuki Tanaka, Yoshinobu Shimamura
    Abstract:

    The present paper employs the Electric Resistance change method for monitoring of location and size of a delamination crack of graphite/epoxy composite laminates. The method is applied to a plate-type specimen with an embedded delamination of cross-ply and quasi-isotropic laminates. Ten electrodes made from copper foil are mounted on the specimen top surfaces. An embedded delamination crack is created by a static indentation test, and the Electric Resistance changes are measured using a conventional strain gage amplifier. Response surfaces are adopted as a tool for solving inverse problems to estimate location and size of delamination crack from the measured Electric Resistance changes of all segments between electrodes. As a result, the present method successfully provides estimations of location and size of the embedded delamination for graphite/epoxy laminated composites.