Details of a Researcher - Takemura, Kenjiro

Papers - Takemura, Kenjiro

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A Micro Artificial Muscle Actuator using Electro-conjugate Fluid

Kenjiro Takemura, Shinichi Yokota and Kazuya Edamura

Proc. Bath Workshop on Power Transmission & Motion Control 269 - 276 2005.09

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

直流高電圧の印加によって活発なジェット流を発生する電界共役流体は，微小な電極対のみによってポンピングできるため，マイクロアクチュエータの駆動源として期待できる．本研究では，上記ジェット流により駆動される液圧駆動型マイクロ人工筋アクチュエータを開発し，駆動特性を明らかにした．実験の結果，直径5 mm，長さ10 mmの人工筋アクチュエータにおいて，収縮率約20 %，発生力約0.2 Nを得た．

電界共役流体に発生するジェット流を用いたマイクロ人工筋アクチュエータ

竹村研治郎，横田眞一，枝村一弥

日本機械学会論文集（C編） 71 ( 708 ) 141 - 147 2005.08

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

電界共役流体は直流高電圧の印加によって活発なジェット流を発生する機能性流体である．すなわち，簡便な電極対のみによって液圧制御が可能であるため，マイクロソフトアクチュエータの駆動源として利用できる．本研究では，軸方向に繊維強化した直径5mmのシリコーンゴムチューブの内圧を上記ジェット流を用いて制御し，軸方向変位を得るマイクロ人工筋アクチュエータを提案し，性能を実験的に確認した．この結果，収縮率は約20%，発生力は0.2N程度であった．

A multi-degree-of-freedom ultrasonic motor using single-phase-driven vibrators

K Otokawa, K Takemura, T Maeno

2005 IEEE/RSJ International Conference on Intelligent Robots and Systems, Vols 1-4 (IEEE) 2259 - 2264 2005.08

Research paper (international conference proceedings), Accepted

This paper presents a novel type of multi degree-of-freedom ultrasonic motors. Today, in various fields, actuators having multi degrees-of-freedom is needed. In the past, many multi-degree-of-freedom actuators have been developed. However, they are all still large and heavy. Thus, we propose a miniature multi-degree-of-freedom actuator using plural single-phase-driven ultrasonic vibrators. A single-phase-driven ultrasonic motor is known for its miniaturizing facility. On the other hand, it is also known for its lack of output force. Therefore, we proposed to use plural single-phase-driven vibrators and also tried to make one vibrator generate great force. This motor has many small vibrators; each one having four patterns in the thrust direction. By controlling the frequency of each vibrator, we can obtain multiple movements of a movable object. First, we proposed the principles of this motor. Next, we selected vibration modes and designed the size of a vibrator to be 10 x 7.5 x 0.9 mm(3) using finite element analysis. Finally, we measured frequency, vibration, and driving characteristics of the vibrators. The maximum thrust was about 3.14 N and the maximum torque was about 6 mN-m.

Access to Document (DOI)

A Microactuator Driven by Pressure due to ECF-jet

R.Abe, S.Yokota, K. Takemura, K.Edamura

Proc. The First Joint International Conference on Manufacturing, Machine Design and Tribology MAA-401 2005.06

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

ブルドン管のように先端が閉じ、かつ湾曲したチューブの内圧を変化させるとチューブ全体が直線形状へと変形し，アクチュエータを構成できる．本研究では，このような原理を用いて直径1 mmの湾曲したシリコーンゴムチューブの内圧を電界共役流体に発生するジェット流により変化させる新たなマイクロアクチュエータを提案し，プロトタイプを開発した．また，実験により先端変位1 mm以上を発生できることを確認した．

A Micro Artificial Muscle Actuator using Electro-conjugate Fluid

Kenjiro Takemura, Shinichi Yokota, Kazuya Edamura

Proc. IEEE International Conference on Robotics and Automation 534 - 539 2005.04

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

電界共役流体は直流高電圧の印加によって活発なジェット流を発生する機能性流体である．本研究では，上記ジェット流によって軸方向に繊維強化されたシリコーンゴムチューブの内圧を変化させ，軸方向の収縮と径方向の膨張を得る直径5 mmのECFマイクロ人工筋アクチュエータを開発した．本アクチュエータは液圧駆動アクチュエータであるものの，電界共役流体を用いることにより，外部に大規模なタンクや液圧源を必要としない．

High-integration Micromotor using Electro-conjugate Fluid (ECF)

Shinichi Yokota, Kiyomi Kawamura, Kenjiro Takemura, and Kazuya Edamura

Journal of Robotics and Mechatronics 17 ( 2 ) 142 - 148 2005.04

Research paper (scientific journal), Joint Work, Accepted

高電圧印加時に電界共役流体に発生する活発なジェット流を回転運動に変換するマイクロモータのうち，円盤形ロータ上に電極対を配置したDP-RE形ECFマイクロモータの高集積化について検討した．モータ直径の微小化および円盤形ロータの積層数増加によって，出力パワー密度が著しく向上することを実験的に確認した。すなわち，内径9 mmと5 mmのモータを比較すると出力パワー密度が約2.3倍に，積層数4層と8層のモータを比較すると出力パワー密度が約13.4倍に向上することを明らかにした．

超音波ブレーキの開発

小山辰也，竹村研治郎，前野隆司

日本機械学会論文集（C編） 71 ( 703 ) 111 - 116 2005.03

Research paper (scientific journal), Joint Work, Accepted

本研究では，超音波モータの高応答性，静粛性，単純構造，電磁ノイズレスなどの優れた特徴を有する新たなブレーキシステムを提案した．本ブレーキは超音波浮揚現象を利用してロータのロックと解放を切り替えるものである．はじめに，有限要素法を用いた振動子の振動設計および超音波浮揚理論による保持トルクの計算を行った．つぎに，プロトタイプを試作し，実験によって40Nの浮揚力と0.38Nmの保持トルクが実現可能であることを示した．

Development of a Micro Artificial Muscle Actuator using Electro-conjugate Fluid (ECF)

Kenjiro Takemura, Shinichi Yokota, Kazuya Edamura

Proc. The 8th International Conference on Mechatronics Technology 221 - 226 2004.11

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

電界共役流体は直流高電圧の印加によって活発なジェット流を発生する機能性流体である．すなわち，簡便な電極対のみによって液圧制御が可能であるため，マイクロソフトアクチュエータの駆動源として利用できる．本論文では，軸方向に繊維強化した直径5mmのシリコーンゴムチューブの内圧を上記ジェット流を用いて制御し，軸方向変位を得るマイクロ人工筋アクチュエータを提案し，性能を実験的に確認した．この結果，収縮率は約20%，発生力は0.2N程度であった．

Design of a Plate Type Multi-DOF Ultrasonic Motor and its Self-Oscillation Driving Circuit

K. Takemura, Y. Ohno, and T. Maeno

IEEE/ASME Transactions on Mechatronics (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC) 9 ( 3 ) 474 - 480 2004.09

Research paper (scientific journal), Joint Work, Lead author, Accepted, ISSN 1083-4435

Multi-degrees-of-freedom (DOF) actuators have become more useful in the field of robotics, as a result of the increasing number of DOFs of systems. The general features of ultrasonic motors are suitable for constructing a direct-drive multi-DOF actuator. However, previously developed ultrasonic motors do not have advantages in volume and weight in contrast to multi-DOF motion units composed of plural electromagnetic motors. In the present study, authors developed a novel multi-DOF ultrasonic motor with a compact plate stator and spherical rotor. First, a new driving principle of the motor is proposed. Next, the stator geometry is designed in detail using the finite element method, and a prototype of the multi-DOF ultrasonic motor is produced. Then, vibration characteristics of the stator and driving characteristics of the motor have been measured, respectively. The results confirm that the motor successfully provides the desired multi-DOF motion of the rotor around orthogonal axes driven by a single plate stator. Finally, a novel self-oscillation driving circuit for the motor is proposed and driving tests using the circuit are conducted.

Access to Document (DOI)

Study on Multi-DOF Ultrasonic Actuator for Laparoscopic Instrument

Shinsuk Park, Kenjiro Takemura and Takashi Maeno

JSME International Journal Series C 47 ( 2 ) 574 - 581 2004.07

Research paper (scientific journal), Joint Work, Accepted, ISSN 1344-7653

In surgical robots, compact manipulators with multi-degree-of-freedom (DOF) are essential owing to a small work volume in the patient body. Conventional single-DOF actuators such as electromagnetic motors require a multiple number of actuators to generate multi-DOF motion, which in turn results in bulky mechanism combined with transmission device. Our previous work has developed a compact ultrasonic motor capable of generating a multi-DOF rotation of a spherical rotor utilizing three natural vibration modes of a bar-shaped stator. The present study designs and builds a novel multi-DOF master-slave system for laparoscopic surgical procedures, using a single ultrasonic actuator. The system consists of surgical forceps on multi-DOF wrist with joystick controller. Experimental results have confirmed high responsiveness and precise position control of the master-slave system.

Access to Document (DOI)

Development of a Multi-Degree-of Freedom USM Using Single Mode of Vibrations

Kayo Otokawa, Takashi Maeno, Kenjiro Takemura

Proc. International Conference on Acoustics 2004 IV 3231 - 3234 2004.04

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

従来の多自由度超音波モータの多くは，複数の固有振動モードの固有振動数を縮退させ，これらの組み合わせによって回転子の多自由度運動を実現していた．しかし，振動設計が複雑となるため，実用上問題が多かった．本研究では，複数の振動子をマトリクス状に配置し，固有振動数が異なる複数の固有振動モードを選択的に組み合わせることによって振動子マトリクス上に置かれた移動子に多自由度運動を生成する新たな多自由度超音波モータを開発した．

A Wire-Driven Miniature Five Fingered Robot Hand using Elastic Elements as Joint

Yoichi Ogahara, Yusuke Kawato, Kenjiro Takemura, Takashi Maeno

Proc. The 2003 IEEE/RSJ International Conference on Intelligent Robotics and Systems 2672 - 2677 2003.10

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

マイクロロボットハンドなどの微小な機械システムでは，スケール効果によって摺動部などでの損失の影響が増大するため，一般的な機能要素を用いた設計には限界がある．このため，本研究では関節に弾性ヒンジを用いた5指マイクロロボットハンドを開発した．本ハンドはワイヤ駆動によってヒト指と同様にMP，PIP，DIP関節を駆動する構成である．弾性ヒンジの利用によって，摺動損失の低減およびスペース効率の向上を実現した．

Development of an Ultrasonic Clutch

T. Koyama, K. Takemura, and T. Maeno

Proc. 2003 IEEE International Ultrasonic Symposium (IEEE) 1141 - 1144 2003.10

Research paper (international conference proceedings), Joint Work, Accepted, ISSN 1051-0117

In the present paper, a newly developed ultrasonic clutch is proposed. The ultrasonic clutch can solve problems of conventional passive elements, such as time delay, instability, and large size, by using unique characteristics of ultrasonic motor, as fast response, silent motion, and non-magnetic feature. It can also be designed to be smaller than conventional elements due to its simple structure. The clutch locks or releases the rotor by use of ultrasonic levitation phenomenon. First, we have designed the structure of the ultrasonic clutch using an equation of ultrasonic levitation phenomenon, results from structural analysis and finite element (FE) analysis of piezoelectric material of the vibrator. Then we have manufactured the ultrasonic clutch and have conducted a driving experiment. Finally, we have demonstrated that the maximum levitation force is around 20 N and the static friction torque of the ultrasonic clutch is up to 0.14 Nm.

The Frictional Characteristics of Single-Phase Drive-Type USM

Y. Nakagawa, K. Takemura, and T. Maeno

Proc. 2003 IEEE International Ultrasonic Symposium (IEEE) 1762 - 1765 2003.10

Research paper (international conference proceedings), Joint Work, Accepted, ISSN 1051-0117

In this paper we analyze the mechanical characteristics of the single-phase-drive type ultrasonic motors. Though single-phase-drive type ultrasonic motors (USMs) has many merits against the multi-phase-drive type USMs, the research of them are not popular and the design method is not established yet. We simulated the static driving characteristics of the single-phase-drive type USM and cleared up the relationship between design parameters and T-N curve, output power and frictional efficiency. Finally we will show the adequacy of the simulations by conducting the driving tests.

Development of an Ultrasonic Clutch for Multi-Fingered Exoskeleton Haptic Device using Passive Force Feedback for Dexterous Teleoperation

Tatsuya Koyama, Kenjiro Takemura, Takashi Maeno

Proc. The 2003 IEEE/RSJ International Conference on Intelligent Robotics and Systems (IEEE) 2229 - 2234 2003.10

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

A novel multi-fingered exoskeleton haptic device using passive force feedback has been proposed by the authors. The haptic device solves the conventional problems of previously developed master-slave systems with force feedback, such as oscillations, complex structures and complicated control algorithm. However some problems still remain in the conventional passive elements. In the present paper an ultrasonic clutch for multi-fingered exoskeleton haptic device with passive force feedback function is developed. The ultrasonic clutch can solve problems of conventional passive elements, such as time delay, instability, and large size, by using unique characteristics of ultrasonic motor as fast response, silent motion, and non-magnetic feature. It can also be designed to be smaller than conventional elements due to its simple structure. The clutch locks or releases the rotor by use of ultrasonic levitation phenomenon. First, we have designed the structure of the ultrasonic clutch using an equation of ultrasonic levitation phenomenon, results from structural analysis and finite element (FE) analysis of piezoelectric material of the vibrator Then we have manufactured the ultrasonic clutch and have conducted a driving experiment. Finally, we have demonstrated that the maximum levitation force is around 20 N and the static friction torque of the ultrasonic clutch is up to 0.14 Nm.

Development of a Robot Finger for Five-fingered Hand using Ultrasonic Motors

Ikuo Yamano, Kenjiro Takemura and Takashi Maeno

Proc. The 2003 IEEE/RSJ International Conference on Intelligent Robotics and Systems (IEEE) 2648 - 2653 2003.10

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

A robot finger is developed for five-fingered robot hand having equal number of DOF to human hand. The robot hand is driven by a new method proposed by authors using ultrasonic motors and elastic elements. The method utilizes restoring force of elastic element as driving power for grasping an object, so that the hand can perform the soft and stable grasping motion with no power supply. In addition, all the components are placed inside the hand thanks to the ultrasonic motors with compact size and high torque at low speed. Applying the driving method to multi-DOF mechanism, a robot index finger is designed and implemented It has equal number of joints and DOF to human index finger, and it is also equal in size to the finger of average adult male. The performance of the robot finger is confirmed by fundamental driving test.

Development of Multi-DOF Actuators for Surgical Tools

Shinsuk Park, Kenjiro Takemura and Takashi Maeno

Proc. The 32nd International Congress and Exposition on Noise Control Engineering 3039 - 3046 2003.08

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

腹腔鏡下手術は腹部にあけた直径10mm以下の穴を介して鉗子および腹腔鏡を体内に挿入し腹腔鏡画像下で手術する低侵襲手術である．患者への負担が少ない代わりに術者には高いスキルが要求される．本研究では，球状回転子に直交3軸回りの多自由度回転を生成し得る多自由度超音波モータを用いて，鉗子先端に手首のような多自由度運動を実現する多自由度鉗子のプロトタイプを実現した．

Design of a Plate Type Multi-DOF Ultrasonic Motor and its Driving Characteristics

Kenjiro Takemura, Yuji Ohno and Takashi Maeno

Proc. IEEE/ASME International Conference on Advanced Intelligent Mechatronics (IEEE) 1309 - 1314 2003.07

Research paper (international conference proceedings), Joint Work, Lead author, Accepted, ISSN 2159-6255

Multi-DOF actuators have become more useful in the field of robotics, thanks to the increasing number of DOFs of systems. General features of ultrasonic motor are suitable for constructing a direct-drive multi-DOF actuator. However, those previously developed do not have advantages in volume and weight against the multi-DOF motion unit composed of several electromagnetic motors. In the present study authors develop a novel multi-DOF ultrasonic motor with a plate stator and a spherical rotor. First, a new driving principle of the motor is proposed. Next, the stator geometry is designed in detail using finite element method, and the prototype of the multi-DOF ultrasonic motor with plate stator is produced. The stator is relatively compact against the rotor. Then, vibration characteristics of the stator and driving characteristics of the motor have been measured respectively. The result confirms that the motor successfully provides the multi-DOF motion of rotor around orthogonal axes by single plate stator. Finally, self-oscillation driving circuit for the motor is proposed.

Method for Controlling Multi-DOF Ultrasonic Motor using Neural Network

Kenjiro Takemura and Takashi Maeno

Journal of Robotics and Mechatronics 15 ( 2 ) 114 - 120 2003.04

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

多自由度超音波モータは振動方向が互いに直交する3つの固有振動モードを組み合わせて球状回転子に任意軸回りの回転運動を生成する．すなわち，入力パラメータ7つに対して出力3つとなる冗長非線形性を有している．したがって，所望の駆動状態を実現するための入力の組み合わせは複数存在するため，超音波モータに対する経験的所見とニューラルネットワークによる非線形写像を組み合わせて，所望の駆動状態に対して唯一の入力を決定する逆モデルを提案し，これを用いて多自由度超音波モータの駆動制御を実現した．

パッシブフォースフィードバックを用いた多指エクゾスケルトン型ハプティックデバイスの開発

小山辰也，山野郁男，竹村研治郎，前野隆司

日本バーチャルリアリティー学会論文誌 7 ( 4 ) 565 - 574 2002.12

Research paper (scientific journal), Joint Work, Accepted

本研究では，物体との接触／非接触によって力／位置のフィードバックが切り替えられるパッシブフォースフィードバック制御法を提案した．また，本制御法を用いて複雑な手指動作のテレオペレーションを実現する多指エクゾスケルトン型ハプティックデバイスを開発した．本デバイスは，操作者の指先端に接続したリンクとリンク根元部に配置されたクラッチから構成される．操作者に反力を提示する際にはクラッチによるリンク全体の固定とデバイス内の弾性要素の変形を利用する．

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