Details of a Researcher - Takemura, Kenjiro

Papers - Takemura, Kenjiro

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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．

Multi-Fingered Exoskeleton Haptic Device using Passive Force Feedback for Dexterous Teleoperation

Tatsuya Koyama, Ikuo Yamano, Kenjiro Takemura and Takashi Maeno

Proc. 2002 IEEE/RSJ International Conference on Intelligent Robotics and Systems (IEEE) 2905 - 2910 2002.09

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

A novel control, methodology for master-slave systems using passive force feedback has been proposed by the authors. The methodology solves the conventional problems of previously developed master-slave systems with force feedback, such as oscillations, complex structures and complicated control algorithm. In the present paper a multi-fingered exoskeleton haptic device (master hand) with passive force feedback function is developed. First, the exoskeleton master hand with three fingers (12 degrees of freedom) is designed and implemented. Each finger of the master hand consists of a link mechanism with elastic-shaft joints and clutches. Using link mechanisms, the master hand measures fingertip positions and angles of index finger middle finger and thumb. Furthermore, it also enables passive force feedback to an operator by the same link mechanism used for the geometric measurements. Then, a virtual reality system of human hand is constructed using the master hand and the control methodology. Using the system, sensory evaluations are conducted on human subjects to confirm the usability of the developed master hand and the possibility of the control methodology in the virtual reality system. As a result, the subjects possibly recognize the stiffness of the objects in the virtual environment.

Control of Multi-DOF Ultrasonic Motor using Neural Network based Inverse Model

Kenjiro Takemura and Takashi Maeno

Proc. 2002 IEEE/RSJ International Conference on Intelligent Robotics and Systems (IEEE) 2187 - 2192 2002.09

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

dA multi-DOF ultrasonic motor developed by the authors is capable of generating multi-DOF rotation of a spherical rotor using three orthogonal natural vibrations of a bar-shaped stator. The ultrasonic motor is suitable for making small, light weight and simple multi-DOF motion unit. In the present paper, a control methodology for the multi-DOF ultrasonic motor is proposed and a motion control test using the method is conducted. First, an inverse model of the multi-DOF ultrasonic motor is developed using our prior knowledge in ultrasonic motors and neural network technique in order to deal with the redundancy and non-linearity of driving characteristics. Second, a novel control method using the inverse model is proposed. Then, motion control tests are conducted to confirm the ability of the proposed control method. The results confirm that the rotor can be rotated around arbitrary rotational axis using the inverse model, and that the proposed control method does work successfully.

Method for Controlling Master-Slave Robots using Switching and Elastic Elements

Ikuo Yamano, Kenjiro Takemura, Ken Endo and Takashi Maeno

Proc. IEEE International Conference on Robotics and Automation (IEEE) 1717 - 1722 2002.05

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

A new type of master-slave control methodology, which has the merits of both unilateral and bilateral ones, is proposed. The methodology is built on switching the unilateral feedback controls of position and force as required using switching and elastic elements. Proposed methodology not only eliminates the demerits of bilateral control, but also supplies the mechanical force feedback to the operator. It utilizes a feature of human factor that direct displacement feedback is not as important as visual and force feedback. Effectiveness of the proposed method is confirmed by experiments using a developed simple single axis master-slave arm system. Driving test of the experimental devices and sensory evaluations are conducted. As a result, it is confirmed that the methodology successfully provides the sense of touch to the operator of the system.

Numerical Analyses on Multi-DOF Ultrasonic Motor - Development of Analysis Method and Results -

Kenjiro Takemura and Takashi Maeno

Proc. IEEE International Conference on Robotics and Automation (IEEE) 2387 - 2392 2002.05

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

A multi-DOF ultrasonic motor developed in our previous study has significant potentials for dexterous actuation. The ultrasonic motor provides multi-DOF rotation of a spherical rotor using three natural vibrations of a bar-shaped stator. In this paper, numerical analyses on the multi-DOF ultrasonic motor are conducted. First, a forward model of multi-DOF ultrasonic motor is developed considering the frictional condition between the rotor/stator. Using the forward model, driving state of the multi-DOF ultrasonic motor under arbitrary combination of vibrations is clarified. Second, an inverse model of the multi-DOF ultrasonic motor is also developed. The inverse model is constructed using experienced knowledge about ultrasonic motor and neural network technique. An appropriate input for the multi-DOF ultrasonic motor with regard to arbitrary rotational axis is estimated using the inverse model. The proposed models are available not only for our motor but for all multi-DOF ultrasonic motors.

Development of a Master-Slave System for Active Endoscope Using a Multi-DOF Ultrasonic Motor

Kenjiro Takemura, Dai Harada, Takashi Maeno

Transactions on Control, Automation and Systems Engineering 4 ( 1 ) 17 - 22 2002.03

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

Design and Control of an Ultrasonic Motor Capable of Generating Multi-DOF Motion

Kenjiro Takemura, Takashi Maeno

IEEE/ASME Trans. Mechatronics (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC) 6 ( 4 ) 499 - 506 2001.12

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

A multi-degree-of-freedom (DOF) ultrasonic motor consisting of a bar-shaped stator and a spherical rotor was developed. It can generate 3-DOF rotation of the rotor around perpendicular axes using bending vibrations and a longitudinal vibration of the stator, which was designed using finite element analysis. From the simulated driving characteristics, a control method for the ultrasonic motor was proposed. Following this, the driving characteristics of the motor under open-loop control and closed-loop control were measured experimentally. Mufti-DOF position control of the rotor was achieved successfully using the proposed control method.

Access to Document (DOI)

A Master-Slave System using a Multi-DOF Ultrasonic Motor and its Controller designed considering Measured and Simulated Driving Characteristics

Kenjiro Takemura, Dai Harada, and Takashi Maeno

Proc. 2001 IEEE/RSJ International Conference on Intelligent Robots and Systems (IEEE) 1977 - 1982 2001.10

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

Master-slave active robot hands and endoscopes, which provide dexterous manipulations and wide views like human hands and eyes, are required to be constructed. We have previously developed a multi-DOF ultrasonic motor consisting of a spherical rotor and a bar-shaped stator. The rotor rotates around three perpendicular axes using three natural vibration modes of the stator. In this study, a multi-DOF unilateral master-slave system using the multi-DOF ultrasonic motor is developed. Master and slave arms for the system have similar configurations, so that an operator can easily handle the master-slave system. First, driving characteristics of the multi-DOF ultrasonic motor are clarified experimentally and analytically in order to design the slave arm and its controller. Next, the master-slave arms and the unilateral feedback controller for the master-slave system are developed. Finally, the motion control tests of the system are performed to show the applicability of the master-slave system.

多自由度超音波モータの駆動状態推定法

竹村研治郎，前野隆司

日本音響学会誌 (日本音響学会) 57 ( 7 ) 445 - 452 2001.07

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

多自由度超音波モータは，振動子の互いに直交する固有振動モードを適当な位相差をもって励振し，回転子に多自由度回転運動を実現するものである．しかし，各振動モードの振幅および位相が任意の値となるときの回転子の回転軸は容易に予想できない．このため，本研究では各固有振動モードが任意の振幅および位相で励振された際に回転子におよぼす駆動力を摩擦モデルにより算出し，このときの回転軸，トルクおよび回転速度を推定する手法を提案した．

Development of a Master-Slave System for Active Endoscope using a Multi-DOF Ultrasonic Motor

Kenjiro Takemura, Dai Harada, and Takashi Maeno

Proc. The 32nd International Symposium on Robotics 254 - 259 2001.04

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

多自由度超音波モータは円柱状振動子の縦振動と曲げ振動を適当に組み合わせることによって振動子先端に加圧接触された球状回転子に直交3軸回りの多自由度回転運動を生成するモータである．このため，上記モータを能動内視鏡の駆動に応用することを提案した．本研究では能動内視鏡のプロトタイプを開発するとともに，マスタ・スレーブシステムとして駆動制御を実現した．

Method for Controlling a Multi-DOF Ultrasonic Motor using a Sigmoid Function

Kenjiro Takemura, T. Maeno

Proc. The 5th International Conference on Motion and Vibration Control 427 - 432 2000.12

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

本研究では，円柱状振動子の縦振動と曲げ振動を用いた多自由度超音波モータの設計および駆動制御を行った．多自由度超音波モータは励振する縦振動および曲げ振動の位相差を-90度から90度まで連続に変化させることによって回転速度をCWからCCWまで連続に変化させることができる．このため，上記の位相差を操作パラメータとしてシグモイド関数を用いて-90度から90度まで所望の回転数に応じて変化させる多自由度超音波モータの速度制御法を提案した．

Characteristics of an Ultrasonic motor Capable of Generating a Multi-Degrees of Freedom Motion

Kenjiro Takemura, Takashi Maeno

Proc. IEEE International Coference on Robotics and Automation 3660 - 3665 2000.04

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

円柱状振動子の固有振動モードのうち，縦振動1次モードと曲げ振動2次モードを縮退させ，これらを適当な位相差をもって励振することによって，振動子先端に接触した球場回転子に多自由度運動を生成する多自由度超音波モータを開発した．本研究では，本モータを直交3軸回りに駆動させた際の無負荷回転特性および速度-負荷特性を実験によって明らかにした．

縦振動と横振動の縮退に基づく多自由度超音波モータの開発

前野隆司，竹村研治郎，小島信行

日本ロボット学会誌 (日本ロボット学会) 16 ( 8 ) 1115 - 1122 1998.11

Research paper (scientific journal), Joint Work, Accepted

円柱状振動子の縦振動と横振動を用いた多自由度超音波モータを実現した．すなわち，円柱の固有振動モードのうち振動方向が互いに直交し，縮退する縦振動と2つの横振動を適当な位相差をもって励振し，振動子先端に直交3軸回りの楕円運動を生成すると，振動子先端に接触した球状回転子は上記軸回りに多自由度回転される．本研究では，駆動原理の提案，有限要素法を用いた振動設計およびプロトタイプによる駆動確認を行った．

Development of a Bar-Shaped Ultrasonic Motor for Three-Degrees of Freedom Motion

K. Takemura, N. Kojima, and T. Maeno

Proc. The 4th International Conference on Motion and Vibration Control 195 - 200 1998.08

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

円柱状振動子の縦振動と曲げ振動を用いた多自由度超音波モータを実現した．すなわち，円柱の固有振動モードのうち振動方向が互いに直交し，縮退する縦振動と2つの曲げ振動を適当な位相差をもって励振し，振動子先端に直交3軸回りの楕円運動を生成すると，振動子先端に接触した球状回転子は上記軸回りに多自由度回転される．本研究では，駆動原理を提案し，プロトタイプによって原理を確認した．

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