Details of a Researcher - Takemura, Kenjiro

Papers - Takemura, Kenjiro

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Robotic Earthworm using Electro-conjugate Fluid - Confirmation of fundamental principle -

Kenichiro Tokida, Kenjiro Takemura, Shinichi Yokota, Kazuya Edamura

Proc. The 13th International Conference on Mechatronics Technology CD-ROM 2009.10

Research paper (international conference proceedings), Joint Work, Corresponding author, Accepted

A multi-purpose Micro Fluid Power Component using Ultrasonic Vibration

Jun Gomi, Kenjiro Takemura

Proc. The 13th International Conference on Mechatronics Technology CD-ROM 2009.10

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author, Accepted

A Dual-Axis Liquid Rate Micro Gyroscope using Electro-conjugate Fluid

Yoshitsugu Ogawa, Shinichi Yokota, Kazuya Edamura, Kenjiro Takemura

Proc. The 13th International Conference on Mechatronics Technology CD-ROM 2009.10

Research paper (international conference proceedings), Joint Work, Accepted

Robotic Earthworm using Electro-conjugate Fluid

Kenichiro Tokida, Kenjiro Takemura, Shinichi Yokota, Kazuya Edamura

Proc. The 14th International Symposium on Applied Electromagnetics and Mechanics 633 - 634 2009.09

Research paper (international conference proceedings), Joint Work, Corresponding author, Accepted

ECF Liquid Rate Gyroscope

Shinichi Yokota, Mitsutoshi Hongo, Kenjiro Takemura, Kazuya Edamura, Tsunehiko Imamura, Hideo Kumagai

Proc. The 14th International Symposium on Applied Electromagnetics and Mechanics 13 625 - 626 2009.09

Research paper (international conference proceedings), Joint Work, Accepted, ISSN 1343-2869

An electro-conjugate fluid (ECF) is a kind of functional fluid, which generates a powerful jet flow (ECF jet) when subjected to a high DC voltage. This study applies the ECF on a novel liquid rate gyroscope. The gyroscope has a liquid flow inside generated by the ECF jet When a rate is applied to the gyroscope, the flow drifts due to the Coliolis force. The gyroscope senses this drift by using hotwires to detect the applied rate. A prototype could successfully detect the applied rate with appropriate response.

Electrokinetic Actuation of Low Conductivity Dielectric Liquids

R.V. Raghavan, J. Qin, L.Y. Yeo, J.R. Friend, K. Takemura, S. Yokota, K. Edamura

Sensors & Actuators B (ELSEVIER) 140 ( 1 ) 287 - 294 2009.06

Research paper (scientific journal), Joint Work, Accepted, ISSN 0925-4005

There has been some amount of confusion over the origin of electrohydrodynamic phenomena responsible for the actuation of dielectric fluids in the presence of an electric field. Previous studies have accounted for the possibility of conduction pumping, ion drag pumping and induction pumping as driving mechanisms but have ignored the possibility of Maxwell (electric) pressure driven flow. Until recently, this mechanism has been poorly understood and as a result has often been overlooked. This paper demonstrates how a Maxwell pressure gradient can induce flow in dielectric liquids in the presence of a non-uniform field. We derive, from first principles using lubrication theory, an expression for the flow velocity which exhibits a quadratic dependence on the applied voltage and also proportionality to the ratio of the permittivity and viscosity. The theoretical predictions are supported by experimental results. Although we have examined the phenomenon for a particular class of dielectric liquids, it is believed that this mechanism could well be responsible for the actuation of other low conductivity dielectric fluids previously attributed to conduction or ion drag pumping. In any case, we discuss ways to identify the dominant mechanism by comparing the salient features for a given type of flow.

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A micro liquid rate gyroscope using an electro-conjugated fluid

Shinichi Yokota, Tsunehiko Imamura, Mamoru Suzuki, Kenjiro Takemura, Kazuya Edamura, Hideo Kumagai

Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C (Japan Society of Mechanical Engineers) 75 ( 750 ) 496 - 502 2009.02

Research paper (scientific journal), Joint Work, Accepted, ISSN 0387-5024

We propose in this study a novel concept of a liquid rate gyroscope using electro-conjugate fluid. The electro-conjugate fluid (ECF) is a dielectric fluid which works here as a functional/smart fluid generating a powerful jet flow (ECF jet) under a high DC electric field. The ECF liquid rate gyroscope proposed senses the drift of the liquid flow due to Coriolis force when an angular rate is applied. The contribution of the proposed concept on gyroscope technology is to provide a possibility for a low cost micro gyroscope with impact resistance. This paper describes a design of ECF micro liquid rate gyroscope and performance evaluations. The results of experiments show the ECF micro liquid rate gyroscope could possibly be a next generation standard of micro gyroscope for consumer products.

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A Liquid Rate Gyroscope using Electro-conjugate Fluid

Kenjiro Takemura, Shinichi Yokota, Mamoru Suzuki, Kazuya Edamura, Hideo Kumagai, Tsunehiko Imamura

Sensors & Actuators A 149 ( 2 ) 173 - 179 2009.02

Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted

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ECF-jet Driven Micro Artificial Muscle Actuators and its Application to an ECF Micro Hand

Shinichi Yokota, Fumiya Yajima, Kenjiro Takemura, Kazuya Edamura

Proc. The Seventh International Conference on Fluid Power Transmission and Control (WORLD PUBLISHING CORPORATION) 33 - 37 2009

Research paper (international conference proceedings), Joint Work

We proposed a novel micro hand in which three kinds of soft actuators driven by ECF jet. The electro-conjugate fluid (ECF) Is, a dielectric fluid that works as a functional fluid, generating a powerful jet flow (ECF jet) when Subjected to high DC voltage. First, we have proposed an ECF micro artificial muscle Cell using ECF and integrated the cells. Second, we newly proposed and fabricated an ECF micro artificial antagonistic muscle, which consist of a pair of sleeve-type artificial muscles like. a McKibben type and a common tube. Finally, we proposed an ECF micro finger which is composed of two Fiber-reinforced soft tubes. The main advantage of the ECF soft actuator is tank and power source built-in.

Practical Design of a Liquid Rate Gyroscope using Electro-conjugate Fluid

Kenjiro Takemura, Shinichi Yokota, Tsunehiko Imamura, Kazuya Edamura, Hideo Kumagai

Journal of Systems and Control Engineering, Proceedings of the Institution of Mechanical Engineers, Part I (PROFESSIONAL ENGINEERING PUBLISHING LTD) 223 ( 6 ) 727 - 736 2009

Research paper (scientific journal), Joint Work, Lead author, Accepted, ISSN 0959-6518

An electro-conjugate fluid (ECF) is a kind of dielectric fluid that works as a functional/smart fluid generating a powerful jet flow (ECF jet) when subjected to a high d.c. voltage. The authors previously proposed the first liquid rate gyroscope in the world using ECF. The ECF liquid rate gyroscope proposed uses the drift of the ECF jet due to the Coriolis force when an angular motion is applied. The contribution of the proposed concept to gyroscope technology is that it provides the possibility of a low-cost micro gyroscope with inherent robustness to external impact. To move beyond a mere laboratory curiosity, the present paper describes the practical design of an ECF liquid rate gyroscope and characterizes the prototype. The ECF liquid rate gyroscope developed in this study has a scale factor, range of detection, resolution, and linearity of 32 mV/(degrees/s), +/-400 degrees/s, 0.04 degrees/s, and 2 per cent of full scale (with a range of +/-60 degrees/s), respectively. These results show that the ECF liquid rate gyroscope could possibly become the next generation standard of micro gyroscopes.

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A Liquid Rate Gyroscope using Electro-conjugate Fluid

Shinichi Yokota, Tsunehiko Imamura, Kenjiro Takemura, Kazuya Edamura, Hideo Kumagai

Proc. The Fourth International Conference on Intelligent Sensors, Sensor Networks and Information Processing CD-ROM 2008.12

Research paper (international conference proceedings), Joint Work, Accepted

A Cell-integrated ECF-jet driven Artificial Muscle Actuator

Fumiya Yajima, Kenjiro Takemura, Shinichi Yokota, Kazuya Edamura

Proc. The 12th International Conference on Mechatronics Technology CD-ROM 2008.10

Research paper (international conference proceedings), Joint Work, Accepted

A Liquid Rate Gyroscope using Electro-conjugate Fluid - Practical Design and Characterization -

Shinichi Yokota, Kenjiro Takemura, Mamoru Suzuki, Kazuya Edamura, Hideo Kumagai and Tsunehiko Imamuras

Proc. IEEE/RSJ 2008 International Conference on Intelligent Robots and Systems CD-ROM 2008.09

Research paper (international conference proceedings), Joint Work, Accepted

Earthworm type Robot driven by Electro-conjugate Fluid

Kenjiro Takemura, Young-Pyo Hong, Kazuya Edamura, Shinichi Yokota

Proc. 17th CISM-IFToMM Symposium on Robot Design, Dynamics, and Control 85 - 92 2008.07

Research paper (international conference proceedings), Joint Work, Lead author, Accepted

Integration of Micro Artificial Muscle Cells using Electro-conjugate Fluid

Kenjiro Takemura, Fumiya Yajima, Shinichi Yokota, Kazuya Edamura

Sensors & Actuators A (ELSEVIER SCIENCE SA) 144 ( 2 ) 348 - 352 2008.06

Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted, ISSN 0924-4247

An artificial muscle is one of the key technologies for soft robots. This paper describes design, fabrication, and characterization of an artificial muscle cell using an electro-conjugate fluid (ECF) and integration of the cells. The ECF is a kind of dielectric and functional fluid, which generates a powerful jet flow or ECF jet under an electrostatic field applied with an electrode pair. It is experimentally clarified that the smaller electrodes generate a more powerful ECF jet with constant voltage applied. The authors propose in this study a new type of micro artificial muscle cell using electro-conjugate fluid (ECF micro artificial muscle cell). This soft actuator having a power source inside is compact enough for integration. By integrating a large number of cells, we can realize a macro-sized artificial muscle. In this paper, we fabricate a prototype of ECF micro artificial muscle cell (emptyset 12.5 mm x 13 mm), and integrate four cells into a 2 x 2 ECF artificial muscle actuator showing larger stroke and force. The maximum stroke and force are 1.56 mm and 320.5 mN with a single cell, and they are increased to be 2.8 mm and 504.1 mN with the 2 x 2 ECF artificial muscle actuator. (C) 2008 Elsevier B.V. All rights reserved.

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Electrokinetic Actuation of Low Conductivity Dielectric Fluids

Rohan Raghavan, Jason Qin, Leslie Y. Yeo, James R. Friend, Kenjiro Takemura, Kazuya Edamura, Shinichi Yokota

Proc. ASME the Sixth International Conference of Nanochannels, Microchannels and Minichannels CD-ROM(ICNMM2008-62239) 2008.06

Research paper (international conference proceedings), Joint Work, Accepted

Concept of a Liquid Rate Gyroscope using an Electro-conjugate Fluid

Shinichi Yokota, Mamoru Suzuki, Kenjiro Takemura, Kazuya Edamura, Hideo Kumagai, and Tunehiko Imamura

Proc. IEEE International Conference on Robotics and Automation (IEEE) 317 - 322 2008.05

Research paper (international conference proceedings), Joint Work, Accepted, ISSN 1050-4729

We propose a novel liquid rate gyroscope using an electro-conjugate fluid in this study. The electro-conjugate fluid (ECF) is a dielectric fluid that works here as a functional/smart fluid generating a powerful jet flow (ECF jet) when subjected to high DC voltage. Using the ECF jet, we developed a liquid rate gyroscope based on the principle of a conventional gas rate sensor operated by Coriolis force. Because the ECF jet is generated only with a tiny electrode pair, the pumping part of proposed ECF gyroscope needs no mechanically moving parts, resulting in making the ECF gyroscope suitable for micro sensor compared to the gas rate sensor having a pumping mechanism inside. We fabricated a prototype of liquid rate gyroscope (40mm x 60mm x t7mm) and confirmed its characteristics by experiment. The experimental results confirm the effectiveness of the proposed liquid rate gyroscope. The scale factor of -29 mV/(degrees/s) is obtained with applied voltage of 4.5 kV.

Control of multi-dof ultrasonic actuator for dexterous surgical instrument

Kenjiro Takemura, Shinsuk Park, Takashi Maeno

Journal of Sound and Vibration (ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD) 311 ( 3-5 ) 652 - 666 2008.04

Research paper (scientific journal), Joint Work, Lead author, Accepted, ISSN 0022-460X

For surgical devices used in minimally invasive surgery, compact multi-degree-of-freedom (multi-dof) actuators are required due to a small work space in the patient body. With conventional single-dof actuators such as electromagnetic motors, a multiple number of actuators are required to generate multi-dof motion. Moreover, additional transmission mechanisms make the total system even larger and heavier. In contrast, a single unit of multi-dof ultrasonic actuator can generate multi-dof rotation of a spherical rotor by utilizing three natural vibration modes of a bar-shaped stator. In our previous work we designed and built a surgical forceps with a wrist capable of two-dof motion, using a single multi-dof ultrasonic motor. The present study proposes a novel control scheme to generate three-dof motion of the surgical instrument for minimally invasive surgical procedures. Through experiments we have confirmed the system performance of the developed device. (c) 2007 Elsevier Ltd. All rights reserved.

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Integration of ECF Micro Artificial Muscle Cells

Funiya Yajima, Kenjiro Takemura, Shinichi Yokota, Kazuya Edamura

Proc. The 11th International Conference on Mechatronics Technology 434 - 439 2007.11

Research paper (international conference proceedings), Joint Work, Accepted

A Micromotor using Electro-conjugate Fluid - Improvement of motor performance by using saw-toothed electrode series -

Kenjiro Takemura, Hiroto Kozuki, Kazuya Edamura, Shinichi Yokota

Sensors & Actuators A (ELSEVIER) 140 ( 1 ) 131 - 137 2007.10

Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted, ISSN 0924-4247

An electro-conjugate fluid (ECF) is a kind of dielectric fluid, which works as a smart fluid. The fluid generates a powerful jet flow, which we call an ECF jet, when subjected to high DC voltage with a highly non-uniform electric field. This means the ECF works as a fluid power source for mechanical components without any bulky pumps. This paper develops a high-performance ECF micromotor having novel saw-toothed electrode series. The motor has four disk plates with the electrode series as a rotor. The inner diameter and length of the motor are 9 and 10.6 mm, respectively. Experimental results confirm that the output power and torque of the motor are 21 times and 7.5 times larger than those of a previous ECF micromotor having bar-shaped electrode pairs. (C) 2007 Elsevier B.V. All rights reserved.

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