Details of a Researcher - Namerikawa, Toru

Papers - Namerikawa, Toru

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Cooperative Capturing for Multi-Agent System with Reaction Force from Target Object

Yoshihiro Tachibana, Toru Namerikawa

2013 PROCEEDINGS OF SICE ANNUAL CONFERENCE (SICE) (IEEE) 1231 - 1236 2013.09

Research paper (international conference proceedings), Joint Work, Last author, Accepted, ISSN 1550-0322

This paper proposes a cooperative control of multi-agent system to capture target object. When the agents capture the target object, they may be subjected to reaction force from it. Therefore, we have to consider the physical contact between the agent and target object. First, we introduce the second order model to consider reaction force from target object. The network topology among agents is time-varying and connected, and information of target object is allowed to be available to at least one agent. Second, we show the proposed control law guarantees the agents capture the target object. The control law consists of graph theory and consensus algorithm, and we analyze the convergence property. Finally, simulation results show the effectiveness of the proposed control law.

Simultaneous Localization and Mapping Problem via the H-infinity Filter with a Known Landmark

Yoshihiro Okawa, Toru Namerikawa

2013 PROCEEDINGS OF SICE ANNUAL CONFERENCE (SICE) (IEEE) 1939 - 1944 2013.09

Research paper (international conference proceedings), Joint Work, Accepted, ISSN 1550-0322

This paper deals with the simultaneous localization and mapping (SLAM) problem via the H-infinity filter with a known landmark. By adding the observation of a known landmark to those of unknown landmarks, the linearized SLAM model satisfies its observability, and its estimation accuracy is improved. To prove the improvement theoretically, this paper shows that the determinant of the estimated error covariance matrix with the observation of a known landmark becomes small compared with that of the conventional H-infinity filter. The convergence of the error covariance matrix is also proven in this paper. With simulations and experimental results, we confirm that the derived theorems for the convergence are correct and that we can accurately estimate the state of the robot and the environment.

Multi-Robot SLAM for Large Scale Map Building using Relative Information of Local Maps

Takaaki Kojima, Yoshihiro Okawa, Toru Namerikawa

2013 PROCEEDINGS OF SICE ANNUAL CONFERENCE (SICE) (IEEE) 164 - 169 2013.09

Research paper (international conference proceedings), Joint Work, Last author, Accepted, ISSN 1550-0322

This paper deals with Multi-Robot SLAM for large scale map building. Specifically, each robot estimates a local map using EKF, and we merge these local maps into a global map. In this paper, we provide a new RLS based algorithm for map merging. First, we transform local maps into relative information which is considered as measurements for the global map. Then, we update the state estimate by RLS considering the weighting of measurements, which is determined by error propagation from the EKF SLAM. We prove the convergence of the error covariance matrix in this algorithm. In experimental results, we confirm the validity of the proposed algorithm and correctness of derived theorems for the convergence.

Cyber Attack Detection and Faults Diagnosis in Power Networks by Using State Fault Diagnosis Matrix

Yuki Fujita, Toru Namerikawa, Kenko Uchida

2013 EUROPEAN CONTROL CONFERENCE (ECC) (IEEE) 398 - 403 2013.07

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

This paper discusses cyber attacks and faults diagnosis method for networked electrical power systems. In this paper, a power system is divided into some areas, and then, some parameters are estimated by Kalman filter in each area. Then we propose a diagnosis method by using called state and output fault diagnosis matrices which are composed of the estimated values, output matrix and so on. These diagnosis matrices can immediately judge which nodes of which area is attacked. Finally, some simulation results are shown to validate the proposed approach.

Distributed Control for Load Frequency of Power Networks based on Iterative Gradient Methods with Line Search

Taichiro Kato , Yu Haraikawa , Toru Namerikawa

計測自動制御学会論文集 (The Society of Instrument and Control Engineers) 49 ( 2 ) 222 - 228 2013.02

Research paper (scientific journal), Joint Work, Accepted

本論文では分散型電源を導入した電力ネットワークに対して, 直線探索付き反復勾配法に基づく系統周波数制御を提案する.
まず, ネットワーク構造を有する大規模システムを各サブシステムの結合系として状態遷移式で表現し, 状態と制御入力を考慮した評価関数を最小化する制御問題を定式化する.
そしてこの制御問題に対して最適制御を計算する際に, 直線探索を付加した反復勾配法に基づく系統周波数制御を提案する. また, エネルギー/情報結合構造の変化に対してもフレキシブルに適応する事が可能である. 直線探索を行う際のステップ幅はArmijoとWolfe の規準の両方を満足しているため, 収束性を保証する事ができる.
最後に分散型電源を導入した電力ネットワークの負荷周波数制御(Lに対して提案制御則を適用する. そして提案制御則を用いることで, 従来制御則に対し評価関数の低減化や周波数変動の抑制など制御性能の向上が達成されていることをシミュレーションで示す.

Covariance Bounds Analysis during Intermittent Measurement for EKF-based SLAM

A.Hamzah、T. NAMERIKAWA

International Journal of Integrated Engineering 4 ( 3 ) 19 - 25 2012.12

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

This paper deals with Extended Kalman Filter(EKF)-based　SLAM estimation considering intermittent measurement. The study proposes a method to ensure that a designer is able to secure the state covariance or system uncertainties even though the mobile robot sometimes losses its measurement data during its observations. EKF which is based on Bayesian, is chosen in this work for estimation purposes in determining mobile robot position and the environment conditions. In addition, as most of estimation techniques uses Bayesian method, our propose results is expected to provide a general estimation guidelines especially on the filter statistical behavior. The analysis started from the review of theoretical studies of EKF including the expected condition occurred when mobile robot do not received information from its sensors. Simulation results have consistently supports our theoretical analysis which determines that a designer can determine the state error covariance explicitly whenever measurement data is not available.

Fault-tolerant Sensor Network based on Fault Evaluation Matrix and Compensation for Intermittent Observation

Kazuya Kosugi, Shinichiro Tokumoto, Toru Namerikawa

2012 IEEE 51ST ANNUAL CONFERENCE ON DECISION AND CONTROL (CDC) (IEEE) 1834 - 1839 2012.12

Research paper (international conference proceedings), Accepted, ISSN 0743-1546

This paper deals with a fault-tolerant sensor network configuration problem for a target navigation.
A sensor network system consists of many sensor nodes and its network connections. Each sensor node can exchange information by wireless communication. A disadvantage of this system's property is that if there is an inaccurate information from a faulty sensor, this information has possibilities to be diffused to other sensors. Therefore, it is important to reduce effects of the inaccurate information by detecting a faulty sensor as possible as we can. And moreover, in feedback control system for navigation, we have to consider a lack of control inputs which happens depending on each sensor's intermittent observation. We propose two estimation methods for constructing a fault tolerant system. Specifically, we propose a fault-evaluation matrix for the fault detection, and we define a novel switching rule for shutting off inaccurate measurement data. Then we also propose a compensation algorithm for the problem of intermittent observation by using an estimated observation value.

Improving Tracking Performance of Passivity Based PID-Type Teleoperation Systems with Communication Delay

Y. Kawai, T. Namerikawa

SICE Journal of Control, Measurement, and System Integration (The Society of Instrument and Control Engineers) 5 ( 6 ) 335 - 341 2012.10

Research paper (scientific journal), Joint Work, Accepted

The goal of this paper is to improve tracking performance of a bilateral teleoperation system with communication
time delay. The proposed method is a passivity-based PID-type controller. First, using feedback passivation control,
we make the master and slave robots passive with respect to the new output including position and velocity signals. Secondly,
we design the PI controller for the new output. In the proposed method, position coordination is achieved even with
the viscous friction error situation. The stability of the proposed PID teleoperation system and tracking performance are
shown via passivity based stability analysis. Finally, several experimental results show the effectiveness of the proposed
control methodology for teleoperation systems.
Key Words : teleoperation system, communication delay, PID-type controller, tracking performance.

故障評価行列と観測値欠落補償に基づく耐故障性を考慮したセンサネットワークの構成

小杉和也, 滑川徹

計測自動制御学会論文集 (The Society of Instrument and Control Engineers) 48 ( 10 ) 649 - 656 2012.10

Research paper (scientific journal), Joint Work, Accepted

本稿ではまずセンサの観測値にバイアスがかかるような故障に関して観測誤差共分散を用いた故障検出を行う．そしてこの結果と文献の観測値欠落を考慮したを組み合わせて故障の発生に対して状態推定精度を高感度化することにより故障信号の付加により信頼性の低下した観測値の状態推定結果への反映を抑制した推定手法を提案する．次に現時刻の観測データを含む状態推定値の欠落に対し観測値の推定値を用いた補償を行うことで推定精度を向上させる手法を提案し最後にこれらの提案制御則の有効性をシミュレーションにより検証する．次章以降ではまずはじめに問題設定としてセンサノードと制御対象であるプラントのモデル本稿で扱う種類の耐故障問題に関しての定義について述べる．次に設定した評価関数の特性について述べこの性質を利用した近傍比較戦略を提示する．最後に数値シミュレーションと制御実験により提案手法の有効性を検証した結果を示す．

逃避時間回避を考慮したH∞フィルタによる移動ロボットの自己位置推定と環境認識

大川佳寛, 滑川徹

計測自動制御学会論文集 (The Society of Instrument and Control Engineers) 48 ( 10 ) 674 - 682 2012.10

Research paper (scientific journal), Joint Work, Accepted

This paper deals with the Simultaneous Localization and Mapping problem via H1 filter considering finite
escape time. The estimation via H1 filter occurs finite escape time depending on the value of the parameter γ
and then the estimation fails or deteriorates. In order to avoid it, we propose a novel algorithm of the update
equation of the filter gain. The convergence of the error covariance matrices are proven. In simulation and
experimental results, the avoidance of the finite escape time and the correctness of derived theorems for the
convergence are confirmed and then we can show robot’s state and environment information can be estimated.

H∞ Filter－Based Short－term Electric Load Prediction considering Characteristics of Load Curve

T. Namerikawa,　Y. Hosoda

電気学会論文誌C (電気学会) 132 ( 9 ) 1446 - 1453 2012.09

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

This paper deals with H∞ filter－based short－term electric load prediction considering characteristics of load curve. We propose a predictive method to forecast a future electric load demand for 36 hours from 0 PM,and then evaluate the peak and bottom of load curves in the next day. We propose a load model, estimates
unknown parameters of model via H∞ filter using the separated data from holiday and weekday, a same pattern of the previous data have been chosen and assigned to parameters for the model. The simulation
results show the effectiveness of the proposed prediction methodology.

CiNii Research

Robot Localization and Mapping problem with Bounded Noise Uncertainties

Hamzah Ahmad, Toru Namerikawa

2012 IEEE SYMPOSIUM ON INDUSTRIAL ELECTRONICS AND APPLICATIONS (ISIEA 2012) (IEEE) 2012.09

Research paper (international conference proceedings), Accepted

This paper deals with H-infinity Filter based SLAM which is also known as minimax filter to estimate robot and landmarks location whose able to stand for non-gaussian noise characteristics. Based on our findings, by selecting appropriate gamma and initial state covariance matrix in H-infinity Filter, the estimation results can show better performance in comparison to the Kalman Filter approach. From the analysis of convergence properties of H-infinity Filter, it is found that the filter is capable to provide a reliable estimation. Besides, from the simulation results, H-infinity Filter produces better outcome than the Kalman Filter in the nonlinear case estimation. These condition subsequently provides alternative estimation techniques with the capability to ensure and improve estimation in the robotic mapping problem especially in SLAM.

Decentralized Control of Smart Grid by using Overlapping Information

Tomoharu Suehiro, Toru Namerikawa

2012 PROCEEDINGS OF SICE ANNUAL CONFERENCE (SICE) (SOC INSTRUMENT CONTROL ENGINEERS JAPAN) 125 - 130 2012.08

Research paper (international conference proceedings), Accepted

This paper deals with a decentralized control of smart grid by using overlapping information for load frequency of power networks introducing distributed power generations. The control objective is to minimize the cost function of load frequency control problem. We expand the state space of the system of power networks and propose a decentralized state feedback control of subsystems for the expanded system. Then we contract the decentralized feedback law to match the original system. Finally, we show the effectiveness of the load frequency control by using the proposed decentralized control method through the simulation result of decentralized large scale power network systems.

Short-term Photovoltaic Prediction by using H-infinity Filtering and Clustering

Yasuhiko Hosoda, Toru Namerikawa

2012 PROCEEDINGS OF SICE ANNUAL CONFERENCE (SICE) (SOC INSTRUMENT CONTROL ENGINEERS JAPAN) 119 - 124 2012.08

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

This paper deals with prediction algorithm applying for photovoltaic (PV) systems in smart grid. This prediction is aim to predict the amount of the next day of generation using the previous data and the weather forecast which get from Japan Meteorological Agency. The procedure of prediction consists of two steps, the data processing and the unknown parameters estimation. In the data processing, our proposed method considers the characteristics of PV generation using cluster ensemble. We propose the cluster ensemble based on k-means to choose the groups with a correlation with previous data. In the unknown parameters estimation, we provide the regression model for PV generation and the unknown parameters are estimated via H-infinity filtering. The effectiveness of the proposed prediction method is demonstrated through numerical simulations.

Cooperative Control Based on Force-Reflection with Four-channel Teleoperation System

Nam Duc Do, Toru Namerikawa

2011 50TH IEEE CONFERENCE ON DECISION AND CONTROL AND EUROPEAN CONTROL CONFERENCE (CDC-ECC) (IEEE) 4879 - 4884 2011.12

Research paper (international conference proceedings), Accepted

This paper focuses on a new Force-Reflection (FR) algorithm based on input-to-state stability (ISS) small gain theorem in cooperative work of Single Master-Multiple Slave (SMMS) teleoperation system with time varying communication delay. In this work, we propose a new position tracking control for object grasping and a new FR algorithm based on a PD control to transfer the positions, velocities and force information between both sides of teleoperation. The goals of these methods are to achieve the secure grasping by multiple slave robots and improve the tracking performance of the cooperation SMMS teleoperation system. To analyze stability of the system, the ISS small gain approach is used to show the overall force-reflecting teleoperation to be input-to-state stable. Several experimental results show the effectiveness of our proposed method.

Distributed Load Frequency Control of Electrical Power Networks via Iterative Gradient Methods

Toru Namerikawa, Taichiro Kato

2011 50TH IEEE CONFERENCE ON DECISION AND CONTROL AND EUROPEAN CONTROL CONFERENCE (CDC-ECC) (IEEE) 7723 - 7726 2011.12

Research paper (international conference proceedings), Accepted

This paper discusses a distributed control for load frequency of electrical power networks based on iterative gradient methods. The control objective is to minimize the quadratic cost function of load frequency control problem, and we apply the distributed control methodology by using iterative gradient methods to complicated large scale electrical power networks. Iterative gradient methods have good flexibility and they are effective for complicated and time-varying distributed power networks. Several numerical simulation results of distributed power network systems including distributed generations, batteries, and renewable energies in order to show the effectiveness of the load frequency control compared with conventional decentralized control and centralized control.

On Predictive Control for Systems with Information Structured Constraints

Toru Namerikawa , Takeshi Hatanaka and Masayuki Fujita

SICE Journal of Control, Measurement, and System Integration (The Society of Instrument and Control Engineers) 4 ( 6 ) 452 - 459 2011.11

Research paper (scientific journal), Joint Work, Accepted, ISSN 1882-4889

In this paper, we investigate a predictive control problem with information structured constraints motivated
by control of micro grid. A system with information structures is defined as a system in which each subsystem collects
spatio-temporally different information. For the system, we consider a predictive control law and the finite time constrained
optimization problem to be solved online is reduced to a deterministic convex programming problem. Then, we
reduce a control problem for a simple micro grid system to the framework and the effectiveness of the proposed control
and estimation law is demonstrated through a numerical simulation.

10911940390420110430155646PDF1.pdf

Predictive Control and Estimation for Systems with Information Structured Constraints

Toru Namerikawa, Takeshi Hatanaka, Masayuki Fujita

2011 11TH INTERNATIONAL CONFERENCE ON CONTROL, AUTOMATION AND SYSTEMS (ICCAS) (IEEE) Vol. 4 ( No. 6 ) 538 - 543 2011.10

Research paper (international conference proceedings), Accepted

This paper deals with a predictive control and estimation problem with information structured constraints in a constrained finite-time optimal control framework. A large-scale system with information structures is defined as a system in which each subsystem collects spatio-temporally different information, and in general it is necessary to collect and process information in a distributed fashion. We propose a novel predictive control scheme and an estimation law with local information that each distributed subsystem obtains. The effectiveness of the proposed control and estimation law is evaluated through numerical simulations of a simplified micro grid.

Access to Document (DOI)

A Scheduling Strategy based on Neighbor Search for Heterogeneous Sensor Networks

Hamzah Ahmad and Toru Namerikawa

Trans. of the Society of Instrument and Control Engineers (The Society of Instrument and Control Engineers) 47 ( 8 ) 329-336 - 336 2011.08

Research paper (scientific journal), Joint Work

This paper deals with a sensor scheduling problem which considers state dependent noise and processing delay.
A networked sensor system usually consists of a large number of sensors, which can be constructed with some
different types of sensors. We propose a sensor scheduling algorithm based on the neighbor search algorithm
nearby nodes for discrete time heterogeneous systems by minimization problem of assessment function. Finally
experimental results show effectiveness of the proposed method.

10911940391720110430163312PDF1.pdf

CiNii Research

Intermittent Measurement in Robotic Localization and Mapping with FIM Statistical Bounds

Hamzah Ahmad and Toru Namerikawa

IEEJ Transactions on Electronics, Information and Systems (The Institute of Electrical Engineering of Japan) 131 ( 6 ) 1223 - 1232 2011.06

Research paper (scientific journal), Joint Work, Accepted

10911940391720110430163312PDF1.pdf

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