Details of a Researcher - Namerikawa, Toru

Papers - Namerikawa, Toru

Division display 201 - 220 of about 233 ／ All the affair displays >>

滑川徹, 瀬戸洋紀

日本機械学会論文集, C編 (日本機械学会) 71 ( 708 ) 2509-2516 - 86 2005.08

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

本研究では初期状態の不確かさのもとで良好な過渡応答特性とロバスト制御性能を達成するために，H∞DIA制御にロバスト制御性
能を付加するμ-シンセシスの適用を提案する．具体的にはD-KイテレーションにH∞DIA制御を適用したμ-シンセシスを構築することにより所望の性能を有する制御系の設計が期待できる．従来法と比較することにより提案手法が良好な過渡応答特性とロバスト制御性能を示すことを制御実験により確認する．

An H(infinity) DIA control system design of a magnetic bearing considering periodic disturbance

H Seto, T Namerikawa

2005 IEEE INTERNATIONAL CONFERENCE ON CONTROL APPLICATIONS (CCA), VOLS 1AND 2 (IEEE) 227 - 232 2005

Accepted, ISSN 1085-1992

This paper deals with an H(infinity) DIA control system design of a magnetic bearing considering periodic disturbance. R. control problem which treats a mixed Disturbance and an Initial state uncertainty Attenuation (DIA) control is expected to provide a good transient property, and we confirmed that DIA control has a good rotational performance by some experiments.
On the other hand, active magnetic bearings allow contact free suspension of rotors and they are used for various industrial purposes. We derive a mathematical model of the magnetic bearing which has complicated rotor dynamics and nonlinear magnetic property.
In this paper, we propose a modified control system design of R DIA control in order to consider the periodic disturbance for the magnetic bearings. In fact, we get a controller taken a peak at specified frequency by adding a frequency weighting function in generalized plant. Experimental results show that the proposed robust control approach is effective for improving rotational performance.

Robust control of master-slave robot system considering environmental uncertainties

R Lin, T Namerikawa

2005 IEEE/ASME INTERNATIONAL CONFERENCE ON ADVANCED INTELLIGENT MECHATRONICS, VOLS 1 AND 2 (IEEE) 1299 - 1304 2005

Accepted, ISSN 2159-6255

This paper deals with robust control of a master-slave teleoperation robotic system considering environmental uncertainties.
We construct a master-slave system by using two 2-DOF Direct Drive robot manipulators and design a robust control system via impedance shaping and mu-Synthesis considering various uncertainties; e.g., environment and operator dynamics, perturbation of impedance model and time delay in telecommunications.
The proposed control methodology can guarantee the robust stability and the robust performance for all these uncertainties of the master-slave robotic system. Several experimental results show the effectiveness of our proposed approach for various environmental uncertainties.

On the H∞ Control System Design Attenuating Initial State Uncertainties

T. Namerikawa, M. Fujita, R. S. Smith and K. Uchida

Trans. of the Society of Instrument and Control Engineers (The Society of Instrument and Control Engineers) 40 ( 3 ) 307-314 2004.03

Research paper (scientific journal), Joint Work

本稿では従来の結果から直交条件を外して，外乱と初期状態の不確かさの混合減衰無限時間区間H∞制御問題を定式化し，解の存在のための必要十分条件を導出する．さらに，可解条件だけでなく，補償器の1つの厳密な構成法も導出する．また提案手法を実際に磁気浮上システムに適用し，制御系の設計，および数値シミュレーションを行った．結果を従来法と比較することにより，過渡応答特性に関する提案手法の有用性を示した．

磁気浮上系のロバスト制御 (解説)

藤田政之, 滑川徹

機械の研究 46 ( 3 ) 339-347 2003.12

本稿は磁気浮上システムのμ-設計法に関して平易に解説している．まずシステムの数理モデルを導出する際に，公称モデルだけではなく，異なる構造を持つモデルと許容し得るモデルパラメータの摂動の大きさを用いて非構造的な加法的不確かさを導出する方法について述べる．つぎに公称モデルと加法的不確かさから構成されるモデル集合に基づき，ロバスト性能問題を設定し，D-K反復法を用いて制御仕様を達成するロバストコントローラを設計する方法について解説する．最後に制御実験の結果を紹介する．

H∞ Control System Design of the Magnetic Suspension System Considering Initial State Uncertainties

T. Namerikawa and M. Fujita

Trans. IEE of Japan (IEE of Japan) 123-C ( 6 ) 1094-1100 - 1100 2003.06

Research paper (scientific journal), Joint Work, ISSN 1348-8155

This paper deals with H∞ control attenuating initial-state uncertainties, and its application to a magnetic suspension system. H∞ control problem, which treats as a mixed attenuation of disturbance and initial-state uncertainty for linear time-invariant systems in the infinite-horizon case, is examined. The mixed attenuation supplies H∞ controls with good transients and assures H∞ controls of robustness against initial-state uncertainty. We apply this method to a magnetic suspension system, and evaluate attenuation property of the proposed disturbance and initial-state uncertainty via simulations and experiments. © 2003, The Institute of Electrical Engineers of Japan. All rights reserved.

Access to Document (DOI)

A generalized H-infinity control system design attenuating initial state uncertainties

T Namerikawa, M Fujita, RS Smith, K Uchida

PROCEEDINGS OF THE 2002 AMERICAN CONTROL CONFERENCE, VOLS 1-6 (IEEE) 1-6 2204 - 2209 2002

Accepted, ISSN 0743-1619

This paper deals With a generalized H-infinity control attenuating initial-state uncertainties. An H-infinity control problem, which treats a mixed attenuation of disturbance and initial-state uncertainty for linear time-invariant systems in the infinite-horizon case, is examined. The mixed attenuation supplies H-infinity controls with good-transients and assures H-infinity controls of robustness against initial-state uncertainty. We derive a necessary and sufficient condition of the generalized mixed attenuation problem. Furthermore we apply this proposed method to a magnetic suspension system, and evaluate attenuation property of the proposed generalized H (infinity) control approach.

Robust Performance Analysis of Magnetic Bearings

T. Namerikawa and M. Fujita

Trans. IEE of Japan (IEE of Japan) 121-D ( 10 ) 1061-1067 - 1067 2001.10

Research paper (scientific journal), Joint Work, ISSN 0913-6339

This paper deals with uncertain model structures, model validation and robust performance analysis of active magnetic bearings. The dynamics of active magnetic bearing systems are characterized by their instability and complex dynamics of rotor and electromagnets. The feedback control is indispensable to stabilize the system, further the closed-loop systems of magnetic bearings should have robustness for stability and performance against model uncertainties. First we derive a nominal mathematical model of AMBs as a linear state-space model under some assumption and idealization, then we consider the discrepancy between the real physical systems and the obtained nominal design model. This discrepancy can be expressed as the structured uncertainties by Linear Fractional Transformation. These uncertainties include linearization error, parametric uncertainties, unmodeled dynamics, and gyroscopic effect. Then we set the interconnection structure which contains the above structurally represented uncertainties. Next we design a robust controller which achieves robust performance condition. Finally, we validate the interconnection structure with the nominal model and uncertainties, and analyze the robustness of stability and performance of the closed-loop system via the mixed structured singular value.

Access to Document (DOI)

Uncertainty Structure and μ- Synthesis of a Magnetic Suspension System

T. Namerikawa and M. Fujita

Trans. IEE of Japan (IEE of Japan) 121-C ( 6 ) 1080-1087 - 1087 2001.06

Research paper (scientific journal), Joint Work, ISSN 0385-4221

H-infinity control system design attenuating initial state uncertainties: Evaluation by a magnetic suspension system

T Namerikawa, M Fujita, RS Smith

PROCEEDINGS OF THE 40TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-5 (IEEE) 87 - 92 2001

Accepted, ISSN 0191-2216

This paper deals with an H-infinity control attenuating initial-state uncertainties, and its application to a magnetic suspension system. An H-infinity control problem, which treats a mixed attenuation of disturbance and initial-state uncertainty for linear time-invariant systems in the infinite-horizon case, is examined. The mixed attenuation supplies H-infinity controls with good transients or assures H-infinity controls of robustness against initial-state uncertainty. We apply this method to a magnetic suspension system, and evaluate attenuation property of the proposed disturbance and initial-state uncertainty via simulations and experiments.

H∞ Control of a Nonlinear Magnetic Suspension System with Feedback Linearization: An Experimental Study of Robustness and Fragility

R. Suzuki, T. Namerikawa and M. Fujita

Trans. IEE of Japan (IEE of Japan) 120C ( 8/9 ) 1195-1200 - 1200 2000.08

Research paper (scientific journal), Joint Work, ISSN 0385-4221

本論文はフォードバック線形化を用いた非線形磁気浮上系のH∞制御のロバスト性と脆弱性に関して議論している．モデリング検証のため，まず２つの仮定に基づいて２つの非線形モデルを導出し，それぞれにフィードバック線形化H∞コントローラを設計した．つぎにこれらのコントローラを用いてステップ状の力外乱が浮上体に加わった場合の浮上体の位置情報を計測し，ロバスト性，さらにモデル構造に起因する脆弱性に関して検証と考察を行った．

Robust performance analysis of uncertain magnetic bearings

Toru Namerikawa, Masayuki Fujlta

Proceedings of the ASME Turbo Expo (American Society of Mechanical Engineers (ASME)) 4 ( 10 ) 1061-1067 2000

This paper deals with uncertain model structures, model validation and robust performance analysis of active magnetic bearing systems. The dynamics of active magnetic bearing systems are characterized by their instability and complex dynamics of rotor and electromagnets. One of the most critical problems of AMBs is a description of a complex behavior of the dynamics of electromagnets and their forces. The exact description of them is almost hopeless, some approximations and assumptions must be employed, and consequently a discrepancy between the real physical system and the nominal design model cannot be avoided. This discrepancy of the magnetic bearing systems is a serious problem of stability and performance. Hence feedback control is indispensable to stabilize the system, further the closed-loop systems of AMBs should have robustness for stability and performance against model uncertainties. First we derive a nominal mathematical model of AMBs as a linear state-space model under some assumption and idealization, then we consider the discrepancy between the real physical systems and the obtained nominal design model. This discrepancy can be expressed as the structured uncertainties by Linear Fractional Transformation. These uncertainties include linearization error, parametric uncertainties, unmodeled dynamics, and gyroscopic effect. Then we set the interconnection structure which contains the above structurally represented uncertainties. Next we design a robust controller which achieves robust performance condition. Finally, we validate the interconnection structure with the nominal model and uncertainties, and analyze the robustness of stability and performance of the closed-loop system via the mixed structured singular value.

Access to Document (DOI)

Wide area stabilization of a magnetic bearing using exact linearization

Matsumura Fumio, Namerikawa Toru, Murata Noriyuki

Electrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi) (TECHNOMIC PUBL CO INC) 128 ( 2 ) 53 - 62 1999.07

Accepted, ISSN 0424-7760

An active magnetic bearing (AMB) is a bearing used to suspend a rotor by magnetic forces without any contact. Feedback control is indispensable for a magnetic bearing, because it is essentially an unstable system. To design a feedback control system, a linear mathematical model of the plant is convenient; however, the force of the electromagnet is highly nonlinear. Thus, usually a linear approximation around the operating point is employed, but the obtained linearized model cannot express the exact behavior of the system at any other operating points. In this paper, we discuss the wide area stabilization of magnetic bearings using the exact linearization approach. First, we derive a nonlinear mathematical model for a magnetic bearing, then we show that this nonlinear system belongs to a class of exactly linearizable nonlinear systems. Next, by using the exact linearization method, we transfer the nonlinear model of a magnetic bearing to a linear time-invariant state model in spite of change of the operating point and the rotational speed of the rotor. Then we construct the state feedback control system by the conventional LQ method. Finally, we evaluate the validity of our proposed method by experiments.

Access to Document (DOI)

磁気軸受の不確かなモデルとロバスト制御 (解説)

滑川徹, 藤田政之

計測と制御 38 ( 2 ) 87-91 1999.02

磁気軸受は常電導電磁石の吸引力を用いて，回転体の回転方向以外の自由度を拘束し，回転体を完全に非接触で空中に支持する複雑なエレクトロメカニカルシステムと捉えることが出来る．本稿では，まず最近国内外で発表された当該分野の研究論文を中心にモデルとロバスト制御の観点から磁気軸受制御の現状について報告している．さらに著者らの最近の研究結果である，磁気軸受システムの不確かさを考慮したLFT表現についても紹介している．

厳密な線形化による磁気軸受の広域安定化

松村文夫, 滑川徹, 村田徳之

電気学会論文誌D (電気学会) 118D ( 3 ) 410-416 - 410 1998.03

Research paper (scientific journal), Joint Work

本論文では厳密な線形化を用いて磁気軸受の広域安定化を行った．まず磁気軸受に対して非線形モデルを導出し，その非線形モデルが非線形な座標変換と入力変換により厳密線形化可能であることを証明した．そして厳密線形化手法を用いて非線形情報を保存した線形モデルを導出し，線形モデルに対して最適制御により状態フィードバックを設計した．最後に制御実験により，動作点移動，ロータの回転速度変化に対する制御性能・安定性の有効性検証を行った．

磁気浮上系の不確かさの記述と μ-設計 (解説)

滑川徹, 藤田政之

電気学会論文誌C (電気学会) 118C ( 3 ) 289-292 1998.03

実システムを制御する際には，一般には対象となるシステムのモデルを導出し，そのモデルに対して補償器の設計を行い，得られた補償器を実システムに適用する．しかしモデルを導出する際には実システムとモデルにギャップが生じることは避けられない．本稿では，ロバスト制御理論の中核をなすμ-設計法とそれに密接に関わるLFT(Linear Fractional Transformation)を用いた不確かなシステムの表現法に焦点を絞り，不安定系である磁気浮上系への適用例を詳しく紹介している．

Uncertainty structure and mu-design of a magnetic suspension system

T Namerikawa, M Fujita, F Matsumura

PROCEEDINGS OF THE SIXTH INTERNATIONAL SYMPOSIUM ON MAGNETIC BEARINGS (TECHNOMIC PUBL CO INC) 439 - 448 1998

Accepted

This paper deals with modeling, structured uncertainties, mu-analysis and synthesis of a magnetic suspension system. First we derive a nominal model of the plant and consider its structured uncertainties e.g., linearization error, parametric uncertainties, and neglected dynamics. Then we set the interconnection structure which includes the above structurally represented uncertainties. Next we design a robust mu controller which achieves robust performance condition using the structured singular value mu. Finally we evaluate the proposed interconnection structure and verify robustness and performance of the designed mu controller by experiments.

State of the Art of Magnetic Bearings -Overview of Magnetic Bearing Research and Applications – (解説)

F. Matsumura Y. Okada, M. Fujita and T. Namerikawa

JSME Int. Journal, Ser. C (JAPAN SOC MECHANICAL ENGINEERS) 40 ( 4 ) 553-560 - 560 1997.12

Joint Work, ISSN 1340-8062

Magnetic bearings levitate, suspend and guide rotors by magnetic forces without physical contact. The non-contact support offers many advantages and opportunities for a wide variety of applications, Since the First International Symposium on Magnetic Bearings was held in Zurich in 1988, this field of research has expanded, and competition in research and development has been very keen, This review presents the recent trends in applications, control methodologies, sensorless controls, bearingless motors, unbalance control, problems of flexible rotors, eddy current properties and power amplifiers.

Experimental Verification on Gain Scheduled H∞ Robust Control of a Magnetic Bearing

T. Namerikawa, M. Fujita and F. Matsumura

JSME Int. Journal, Ser. C (JSME) 40 ( 4 ) 561-569 - 569 1997.12

Research paper (scientific journal), Joint Work, ISSN 1340-8062

This paper deals with the problem of gyroscopic effect and unbalance vibration of the Magnetic Bearing system. Using a gain scheduled Hm control with a free parameter phi, we design a control system which attenuates the unbalance vibration, and guarantees the stability against the gyroscopic effect in specified rotational speed. Further we implement the controller and evaluate the effectiveness of the proposed approach by experiments. First, our experimental setup is explained, a mathematical model of the magnetic bearing is derived. Then, we introduce the gain scheduled H infinity control with free parameters to a magnetic bearing control, in order to reject the disturbances caused by unbalance of the rotor, and guarantee the stability against gyroscopic effect, even if rotational speed of the rotor changes. At last, several experimental results show the effectiveness of this proposed method.

Experimental Verification on Gain Scheduled H∞ Robust Control of a Magnetic Bearing

Namerikawa Toru, Fujita Masayuki, Matsumura Fumio

JSME International Journal, Series C: Mechanical Systems, Machine Elements and Manufacturing (JSME) 40 ( 4 ) 561 - 569 1997.12

ISSN 1344-7653

This paper deals with the problem of gyroscopic effect and unbalance vibration of the Magnetic Bearing system. Using a gain scheduled H∞ control with a free parameter Φ, we design a control system which attenuates the unbalance vibration, and guarantees the stability against the gyroscopic effect in specified rotational speed. Further we implement the controller and evaluate the effectiveness of the proposed approach by experiments. First, our experimental setup is explained, a mathematical model of the magnetic bearing is derived. Then, we introduce the gain scheduled H∞ control with free parameters to a magnetic bearing control, in order to reject the disturbances caused by unbalance of the rotor, and guarantee the stability against gyroscopic effect, even if rotational speed of the rotor changes. At last, several experimental results show the effectiveness of this proposed method.

　 Previous page - Next page 　