Details of a Researcher - Namerikawa, Toru

Presentations -

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RISE-based robust formation control for multi-UAV system

Komagine Yu, Toyota Ryo, Kotani Kento, Namerikawa Toru

2017 56th Annual Conference of the Society of Instrument and Control Engineers of Japan (SICE),

2017.11

Oral presentation (general)

This paper deals with a robust formation control methodology for the Multi-UAV system with uncertain exogenous disturbance. The fourth-order UAV model with disturbance and the disturbance estimate system is introduced. In order to achieve the rigid formation fight, graph theory and consensus algorithm are utilized and the state of the UAVs converges to desired value by using Leader-Follower structure. The proposed control law includes the Robust Integral of the Sign of error (RISE) for estimation of the disturbance and also involves collision avoidance property based on potential method. The stability and convergent properties are proven based on Lyapunov theory. Finally, several simulation results show the effectiveness of the proposed method compared with a conventional sliding mode control.

Formation control of multi-agent system considering obstacle avoidance

Toyota Ryo, Namerikawa Toru

2017 56th Annual Conference of the Society of Instrument and Control Engineers of Japan (SICE),

2017.11

Oral presentation (general)

This paper deals with distributed and cooperative control algorithm to make each agents to form a formation for a second-order system. However, when forming a formation with a multi-agent system, there is a possibility that the agents collide with each other or collide with obstacles other than the agent. Also, if the agents avoid other agents and obstacles, the distance between agents may be temporarily too far apart. In order to solve these problems, this paper proposes a control algorithm which consists of Leader-Follower structure, consensus algorithm and artificial force based on artificial potential field. For the control algorithm to make agents achieve formation in a decentralized cooperative way, we derive the condition concerning the control gain to ensure stability. In addition, by comparing the amount of energy, we design conditions that ensure collision avoidance between agents, collision avoidance with obstacles, and distance between agents, and also design potential functions that satisfy the conditions. The validity of the control algorithm proposed in this paper is verified by numerical simulations.

Collision Avoidance between Multi-UAV-Systems considering Formation Control using MPC

Ille Marc, Namerikawa Toru

2017 IEEE International Conference on Advanced Intelligent Mechatronics (AIM),

2017.08

Oral presentation (general)

This paper deals with the scenario of two multi- UAV systems (so-called teams), each flying from a starting point to a target point. The teams meet on their ways and have to avoid collisions in the horizontal plane. Both teams work independent of each other but use the same formationcontrol and obstacle-collision-avoidance algorithm. The leaders measure obstacles' positions, use a Kalman Filter to estimate their movement and predict their future positions. With the information about the other agents' positions each agent calculates its reference trajectory. The leader also computes a trajectory to guide the team towards the target point. Distributed MPC is used for each agent to track its reference trajectory. If there is a risk of colliding with an obstacle, the MPC cost function is extended by a penalty term to ensure obstacle collision avoidance. The stability of formation control is proved in this paper. The capability of two teams avoiding collisions is shown in a simulation.

RISE-based cooperative control of uncertain multi-agent system

Tachibana Yoshihiro, Namerikawa Toru

2017 American Control Conference (ACC),

2017.06

This paper proposes a RISE-based cooperative control of uncertain multi-agent system with exogenous disturbances. First, we introduce the second order model with disturbance for agent. The network topology among agents is undirected and connected, and information of reference is allowed to be available to at least one agent. Second, we propose the control law consists of graph theory, consensus algorithm and RISE. Graph theory and consensus algorithm are utilized to converge the states of agents to reference value, and RISE is utilized to suppress the disturbance. Then, we show the proposed control law guarantees the agents achieve synchronization, and derive the condition to achieve the control objective. Finally, simulation results show the effectiveness of the proposed control law.

Detection of replay attack on smart grid with code signal and bargaining game

Irita Takashi, Namerikawa Toru

2017 American Control Conference (ACC),

2017.06

Oral presentation (general)

Ensuring cyber security of smart grid based on supervisory control and data acquisition using information and communications technology has been becoming a major challenge. Especially, a replay attack is a dangerous cyber attack affecting integrity and authorization. The goal of this paper is to detect replay attack that is one of cyber attacks on the sensors of a control system. We propose a detecting method adding intentional noise to not only sensors as code signal but also input. Replay attack can immediately be reflected by using fault diagnosis matrices that are composed of the estimator and observed values even if code signal is decrypted. Finally, we show simulation results to analyze effectiveness of the proposed method.

Transient dynamics of heterogeneous micro grids using second order consensus

Mendoza Fernando Genis, Bauso Dario, Namerikawa Toru

2017 International Conference on Wireless Networks and Mobile Communications (WINCOM),

2017.01

Oral presentation (invited, special)

This paper deals with a network of interconnected micro grids. The transient dynamics is modelled as an averaging process involving dynamic agents in a network. An analysis of the convergence of the consensus dynamics is provided using a network model based approach and by exploiting the properties of the corresponding graph-Laplacian matrix. Furthermore an investigation of the transient dynamics is carried out for different damping and inertial parameters and under different timevarying topologies. Finally a simulation is performed based on a model calibrated on an existing network in the UK under parameter uncertainties.

Optimal Power Demand Management among Consumers with Aggregator considering State and Control Constraints

Yoshihiro Okawa and NAMERIKAWA Toru

2016 IEEE 55th Conference on Decision and Control (CDC) ARIA Resort & Casino (Las Vegas, USA) ,

2016.12

Oral presentation (general)

This paper presents a novel optimal power demandmanagementmethodforpowerconsumerswithanaggregator considering state and control constraints. The aggregator is an organization who manages some consumers to achieve demand response efﬁciently. This paper proposes a power demand adjustment method for the aggregator to allocate power reduction among consumers in a distributed manner. Speciﬁcally, this method simultaneously derives the optimal power reduction of each consumer using a gradient method and determines the control inputs by solving a quadratic programming problem with state and input constraint conditions. This paper also shows the convergence of the proposed algorithm, and ﬁnally, numerical simulation results illustrate the effectiveness of the proposed method.

A Comparative Study of Extended Kalman Filter and H∞ Filtering For State Estimation of Stewart Platform Manipulator

Shady A. Maged, A. A. Abouelsoud, Ahmed M. R. Fath El Bab and NAMERIKAWA Toru

Proceedings of the SICE Annual Conference 2016 (つくば市) ,

2016.09

Oral presentation (general)

This paper presents the estimation of both position and velocity of Stewart Manipulator by means of limbs potentiometer measurements and MEMS inertial sensors. The estimation used the Extended Kalman Filter (EKF) and H∞ optimal filtering technique based on the combination of these sensors. The two types of filters are used as nonlinear state estimators to the Stewart platform which is modeled as a stochastic differential equations due to measurement noise in case of EKF and as a continuous time system model in case of H∞ filtering technique. The results of the both filters are compared with each other on the Stewart platform DELTALAB EX800 using MATLAB SimMechanics toolbox. The simulation results show that Kalman filters are not the best choice for parallel manipulator state estimation as they bear from the hypothesis of statistical noise with zero mean as well as known noise covariance, which may reduce its performance. For these reasons, H∞ filter may be the alternative of Kalman filter.

Optimal pricing algorithm to suppress voltage rise caused by reverse load ﬂow in power distribution grid

Kentaro Nagami and NAMERIKAWA Toru

Proceedings of the SICE Annual Conference 2016 (つくば市) ,

2016.09

Oral presentation (general)

On the Fault Tolerant Control of a Quadrotor Manipulation System via MPC and DOb Approaches

Ahmed Khalifa, Mohamed Fanni and NAMERIKAWA Toru

Proceedings of the SICE Annual Conference 2016,

2016.09

Oral presentation (general)

Recently, the Aerial Manipulation System becomes very attractive for a wide range of applications due to its unique features. However, control of such system is quite challenging. One of the critical challenge is that this system is verysusceptibletoactuators’faults. Inthispaper,aPassiveFaultTolerantControlSystemisproposedtoaddressthisissue withrobustandoptimalperformance. TherobustnessisachievedusingalinearDisturbanceObserver(DOb)loop. Based on the linearization capability of DOb, a standard Model Predictive Control (MPC) is then used and the resulting control scheme is characterized by both a low computational load and optimal actuators’ efforts with respect to conventional nonlinear robust solutions. This controller is tested to achieve the tracking of a point-to-point task space references under the effect of actuators’ faults, picking/releasing a payload, changing the operating region, and measurement noise. Efﬁcacy of the proposed technique is veriﬁed via numerical simulations.

SLAM for a Small UAV with Compensation for Unordinary Observations and Convergence Analysis

Takumi Shinohara and NAMERIKAWA Toru

Proceedings of the SICE Annual Conference 2016,

2016.09

Oral presentation (general)

This paper deals with the Simultaneous Localization and Mapping (SLAM) problem for a small Unmanned Aerial Vehicle (UAV) via extended Kalman Filter (EKF) with compensations for unordinary observations. In the SLAM problem, a robot sometimes loses its proper observations then the estimation accuracy deteriorates. In this paper, to remove the effects of unordinary observations, we propose a novel SLAM method considering unordinary observation based on Mahalanobis distance. The proposed method detects the unordinary observations by comparing the observation values with its estimation and determines the weight of these observations. The convergence of the state error covariance matrix is proven. In experimental validation, we show that the UAV state and environment information can be estimated with the proposed method.

Optimal Trafﬁc Signal Control for Alleviation of Congestion based on Trafﬁc Density Prediction by Model Predictive Control

Hiroaki Nakanishi and NAMERIKAWA Toru

Proceedings of the SICE Annual Conference 2016 (つくば市) ,

2016.09

Oral presentation (general)

The purpose of this paper is to propose an optimal trafﬁc signal control in accordance with trafﬁc density to change every moment in trafﬁc network. We focus on calculating optimal signaling split based on trafﬁc volume prediction by model predictive control. Therefore, we aim the achievement of alleviation of congestion in trafﬁc network considering actual trafﬁc situation. Finally the achievement of the purpose is evaluated by controlling of trafﬁc signal in numerical simulations and the relationship between green time and trafﬁc density is examined.

Flocking Algorithm for Multiple Nonholonomic Cars

Yasuhiro Hayashi1 and NAMERIKAWA Toru

Proceedings of the SICE Annual Conference 2016,

2016.09

Oral presentation (general)

In this paper, a ﬂocking control algorithm for multiple nonholonomic cars is proposed. First, it is shown that the nonholonomic car is linearized by using a virtual vehicle. Second, we deﬁne a metric and topological neighborhood set in order to decide which cars to be next to the other car. Control objectives consist of three rules in boids model as separation, alignment, and cohesion, which is a well-known framework of emerging ﬂock, advocated by Reynolds in 1986. Using the neighborhood set, we show the formation of ﬂocking corresponds to the model. These cars are supposed tobeonastraighthighway,whichenablesustosetanassumptionthateachcarheadstothesamedirectionandreachesthe same velocity eventually. The input for a car consists of the artiﬁcial potential method and LaSalle’s invariance principle is utilized to prove the convergence of the entire vehicle system. Finally, the effectiveness of the presented method is examined through simulation.

Robust-Formation Control of Multi-Autonomous Underwater Vehicles based on Consensus Algorithm

Vina Putranti, Zool H. Ismail and NAMERIKAWA Toru

2016 IEEE Conference on Control Applications (CCA) Part of 2016 IEEE Multi-Conference on Systems and Control (Buenos Aires, Argentina) ,

2016.09

Oral presentation (general)

SoC regulator and DOB-based Load Frequency Control of a Microgrid by Coordination of Diesel Generator and Battery Storage

Takuto Hiranaka, Hyungbo Shim, and NAMERIKAWA Toru

2016 IEEE Conference on Control Applications (CCA) Part of 2016 IEEE Multi-Conference on Systems and Control (Buenos Aires, Argentina) ,

2016.09

Oral presentation (general)

In this paper, the load-frequency control problem of microgrid is discussed. The control is applied to maintain a balance between electric-power demand and supply by controlling the outputs of generators in power systems. However, because of the large-scale introduction of energy from renewable-energy sources, it has become more difﬁcult to maintain this balance. To solve this problem, we consider introducing batteries to microgrid. Therefore, we focus on a microgrid that comprises wind-turbine generators, loads, diesel generators, and batteries. First, we design a generalized plant including the diesel generators and batteries. Then, we apply disturbance observer to decide a reference input to diesel generators and batteries. And, we split the reference input into that for diesel generators and that for batteries considering the differences in the response speeds by applying low-pass ﬁlter. Furthermore, we apply SoC regulator for the state of charge of batteries reaching maximum capacity or minimum capacity. Finally, we perform numerical simulations to verify that the control method can suppress the frequency deviations and deviations in the residual capacity of the battery.

Hybrid Acceleration/Velocity-based Disturbance Observer for a Quadrotor Manipulation System

Ahmed Khalifa, Mohamed Fanni and NAMERIKAWA Toru

2016 IEEE Conference on Control Applications (CCA) Part of 2016 IEEE Multi-Conference on Systems and Control (Buenos Aires, Argentina) ,

2016.09

Oral presentation (general)

Aerial manipulation systems become very attractive for a wide range of applications due to their unique features. However, control of such system is quite challenging due to its high nonlinearities, couplings, and external disturbances. In this paper, a Disturbance Observer (DOb)-based linearization of a quadrotor manipulation system is utilized. The DOb estimates the disturbances and nonlinearities, then compensates them such that one can treat the control problem based on a simple linear control algorithm. However, the current developed DOb schemes in the literature are based on the precise measurement of the acceleration or the estimation of the velocity. Unlike, these methods, we propose a modiﬁed DOb, which is based on both the measured linear accelerations and angular velocities that can be obtained directly from the onboard Inertial Measurement Unit (IMU) and encoders. With this technique, the estimation of nonlinearities and disturbances are carried out without the need of estimation acceleration or velocity, and it is model free. The Effectiveness of the proposed technique is veriﬁed via numerical simulations.

Hierarchical and Cooperative Model Predictive Control for Load Frequency of Power Network

ShunTakamura andNAMERIKAWA Toru

Proceedings of the 35th Chinese Control Conference,

2016.07

Oral presentation (general)

In this paper, frequency control problem of a power network is discussed. The control is conducted to retain power demandsupplybalancebycontrollingoutputofgeneratorsinpowernetwork. However,itisgettinghardertoretainthebalance because of large amount of renewable energy injection. This paper proposes more economic and ef¿cient frequency control method based on hierarchical model predictive control. At ¿rst, we describe model of the power network. Then, the frequency control based on hierarchical and cooperative model predictive control is proposed. The proposed control method consists of economic dispatch and load frequency control. In numerical simulation, we show the effectiveness of the proposed method comparedwiththeconventionalloadfrequencycontrolmethodintermsofsuppressionoffrequencyvariationandfuelcost.

MPC and DOb-based Robust Optimal Control of a New Quadrotor Manipulation System

Ahmed Khalifa, Mohamed Fanni and NAMERIKAWA Toru

2016 European Control Conference,

2016.06

Oral presentation (general)

This paper introduces motion control scheme of a new aerial manipulation system that consists of 2-link manipulator attached to the bottom of a quadrotor. This new system presents a solution for the limitations found in the current quadrotor manipulation systems. It is very attractive for a wide range of applications due to their unique features. However, control of such system is quite challenging because it is naturally unstable, has strong nonlinearities and couplings, has fast dynamics, is very susceptible to parameters variations due to carrying a payload besides the external disturbances like wind, and has actuator limitations. A robust optimal linear control scheme is proposed to address these issues. The proposed control scheme is based on a hybrid linear Model Predictive Control (MPC) and linear Disturbance Observer (DOb) techniques.

Distributed Power Supply-demand Management Based on Negawatt Trading with Energy Storage System

Yoshihiro Okawa NAMERIKAWA Toru

2016 European Control Conference,

2016.06

Oral presentation (general)

—This paper presents a distributed power supplydemand management method based on negawatt trading includingchargeordischargepowerfromenergystoragesystems. In the negawatt trading, power consumers reduce their own power demand and receive monetary reward from the market operator. In order to derive appropriate electricity incentive pricesforconsumersandtouseenergystoragesystemsinpower grids efﬁciently, we deal with a power adjustment problem using some future power supply information in this paper. We then show a novel market algorithm to solve this problem in a distributed manner through market trading among the market operator and consumers. Finally, we verify the effectiveness of our proposed method with numerical simulation results.

Load frequency control of a microgrid based on H∞ control considering response speed of generators

Kenji Masui and Toru NAMERIKAWA

Proc. of IEEE Conference on Decision and Control,

2015.12

Oral presentation (general)

In this paper, we discuss the load-frequency control problem of microgrids.
First, we use dispersion-type power sources such as batteries, and secondly, we apply new control theories. Therefore, we focus on a microgrid that comprises a wind-turbine generator, a diesel generator, and a battery, and we propose a technique based on static H∞ control. First, we design a generalized plant considering the differences in the response speeds of diesel generators and batteries. Then, we apply static H∞ control to the generalized plant. Moreover, we combine a linear matrix inequality (LMI) condition with static H∞ control to avoid control gains that will result in control inputs that are too large. We perform numerical simulations to verify that the controller can suppress the frequency deviations and deviations in the residual capacity of the battery. Furthermore, we show that the approach can be employed to design controllers with lower dimensions, and to avoid undesirable control gains. Finally, we perform experiments using a generator and a variable resistance to confirm the effectiveness of the controller.

Regional demand-supply management based on dynamic pricing in multi-period energy market

Yoshihiro Okawa and Toru NAMERIKAWA

Proc. of IEEE Conference on Decision and Control,

2015.12

Oral presentation (general)

This paper deals with a regional demand response method based on dynamic electricity pricing in a multi-period energy market. In the proposed method, first, the power demand and supply in each area are determined considering power flow using the retail and wholesale electricity prices in a day-ahead market. Next, to adjust for power deviations caused by errors in power generation, our proposed method solves the problem of optimal allocation between power demand reduction by consumers and increased power supply from balancing generators in a real-time market. This paper also shows a distributed algorithm for obtaining the optimal values of each market player in both the day-ahead and real-time markets, and finally, numerical simulation results demonstrate the effectiveness of the proposed method.

LMI-based Formation Control Considering Disconnection of Network Links for a Multi-UAV system

Shouhei Mori and Toru NAMERIKAWA

SWARM 2015: The First International Symposium on Swarm Behavior and Bio-Inspired Robotics,

2015.10

Oral presentation (general)

Flocking Control of a Leader-follower System considering Connectivity Maintenance

Itazuri Kazuki and Toru NAMERIKAWA

SWARM 2015 : The First International Symposium on Swarm Behavior and Bio-Inspired Robotics,

2015.10

Oral presentation (general)

The paper deals with a leader-follower flocking control for a multi-agent system which consists of multiple
agents and a leader. The proposed method enables all agents to be disposed at an uniform distance, reach agreement on a
same velocity with their neighborhood, and to track a moving leader independently. Leader is seen as one of the agents,
in addition, all agents obtain their goal using their neighborhood information only. Furthermore, we suggest the bounded
potential function to guarantee the collision avoidance and connectivity maintenance between the agents. As a result, all
of the swarm can move with preserving flocking configuration. Finally, numerical simulations show the effectiveness of
the proposed method.

Image-based Position Estimation of UAV using Kalman Filter

Takaaki Kojima and Toru Namerikawa

Proceedings of 2015 IEEE Conference on Control Applications,

2015.09

Oral presentation (general)

This paper deals with the position estimation
problem by using the Kalman Filter with compensations for
unexpected observations. In the position estimation problem,
robot observations sometimes yield unexpected values, resulting
in the deterioration of the estimation accuracy. For example,
visual observation with an unmanned aerial vehicle often yields
unexpected results because of blurred images. In this paper,
we propose a method to assigns weights to the observations
in order to remove the effects of unexpected observations. In
the proposed method, unexpected observations are detected by
comparing the observation values with its estimates; the weights
of these observations are then determined. On the basis of
simulation and experimental results, we demonstrate that a
robot’s position can be estimated by the proposed method.

Unscented Kalman filter for position estimation of UAV by using image information

Tang Swee Ho, Kojima Takaaki, Namerikawa Toru, Yeong Che Fai, Su Eileen Lee Ming

Proceedings of SICE Annual conference,

2015.07

Oral presentation (general)

In this paper, the position estimation problem is solved by using unscented Kalman filter with observation uncertainty's compensations. These observation uncertainties causing the estimation become inaccurate in position estimate problem. Visual observation is difficult for an unmanned aerial vehicle equipped with only a monocular-vision camera and often results in observation error because of the detected blurred images. A method to weight the observations is proposed in order to improve the position estimation. Simulation is performed using MATLAB and Simulink to verify the proposed method. The simulation result shows that the proposed method can estimate the position accurately.

Distributed dynamic pricing with alternating decision making of market players

Okawa Yoshihiro, Namerikawa Toru

Proceedings of SICE Annual conference,

2015.07

Oral presentation (general)

This paper deals with a distributed decision procedure for determining the electricity price for a future smart grid. In order to derive the optimal regional prices and improve the convergence speed of the algorithm without private information of market players, we propose a price decision algorithm with an alternating decision making of market players. In this paper, we show that the optimal regional prices derived by using our proposed algorithm maximize the social welfare of power networks which includes profits of power consumers and power suppliers with renewable energy generators. Also, we discuss the convergence property of the proposed price decision algorithm. Finally, the feasibility of our proposed dynamic pricing methodology is shown with numerical simulation results.

Formation Control with Collision Avoidance for a Multi-UAV System using Decentralized MPC and Consensus-based Control

Yasuhiro Kuriki and Toru Namerikawa

Proceedings of the 14th European Control Conference,

2015.07

Oral presentation (general)

In this paper, we propose a cooperative formation
control strategy with collision-avoidance capability for a multi-unmanned aerial vehicle (UAV) system by using decentralized model predictive control (MPC) and consensus-based control. Each of the UAVs plans only its own action to track a trajectory. The trajectory is planned for desired formation flying using a consensus-based control algorithm. Collision-avoidance is regarded as coupled constraints. We show how the optimization problems with collision-avoidance can be solved by each UAV in parallel with the other UAVs so that decisions taken independently by each UAV can ensure consistency with the coupled constraints of collision-avoidance. In addition, we show that our proposed approach hardly affects the computation time to solve the optimization problems with collision-avoidance compared to the time for solving the problems without collision-avoidance. Finally, the proposed approach is validated by simulations.

Decentralized Fault Detection of Multiple Cyber Attacks in Power Network via Kalman Filter

Takashi Irita and Toru Namerikawa

Proceedings of the 14th European Control Conference,

2015.07

Oral presentation (general)

This paper discusses faults diagnosis method of multiple cyber attacks in networked electrical power systems. We deal with a power network of a centralized system, and then, some parameters are estimated by Kalman filter. Using a sensor network system, each of sensor nodes can exchange
information by wireless communication. A fault diagnosis
method is proposed by using both fault detection diagnosis
matrix and fault distinction matrix. The former is composed
of estimated values and observed values. On the other hand,
the latter is composed of observed values and calculated values via the senor network. Finally, the effectiveness of the proposed approach is validated by a simulation experiment.

Dynamic Electricity Pricing via the H-infinity Control Considering Uncertainties in Market Participants' Behavior

Yoshihiro Okawa and Toru Namerikawa

Proceedings of the 14th European Control Conference,

2015.07

Oral presentation (general)

This paper deals with a dynamic pricing via the
H-infinity control considering uncertainties in market participants' behavior. The dynamic pricing is a decision procedure of an electricity price based on power demand and supply information from selfish power consumers and generators. However, since market participants have uncertainties in their behavior, the price decision procedure is required to have robustness
against these uncertainties for stable operation of power systems. Then, in this paper, we propose a novel price decision procedure via the H-infinity control and also show the effectiveness of our proposed price decision method in simulation results.

Power system stabilization by direct load control based on strategy-proofness and individual rationality

Sato Ryutaro, Namerikawa Toru

Proceedings of American Control Conference,

2015.07

Oral presentation (general)

This paper proposes a novel direct load control method to stabilize the system frequency. The proposed method utilizes the consumers' controllable loads for load frequency control. By solving an optimization problem to maximize the social welfare function, the input required for the frequency control is allocated among the controllable loads and the load frequency control generator in an economically rational manner. To introduce the direct control program for smooth operation of the power system, preventing consumers from cheating and guaranteeing their benefits are required. Thus, strategy-proofness and individual rationality based on the Groves and Clarke mechanism were used to design the electricity charge. Each consumer bids on the utility functions truthfully to the independent system operator and gains from participating in the proposed direct load control program. The effectiveness of the proposed method was demonstrated through numerical simulations.

Short-Term Wind Power Prediction via Kalman Filter

Tomoki ishikawa and Toru Namerikawa

Proceedings of IEEJ International Workshop on Sensing, Actuation, and Motion Control,

2015.03

Oral presentation (general)

This paper addresses wind power prediction which is known to be a key technology in EMS(Energy Management
Systems). In this paper, 24 hours ahead power prediction method using a filtering theory is proposed for wind power
generation. The prediction method is a simple algorithm, the procedure of prediction consists of two steps, the data
processing and the calculation of predicted values. In the calculation of predicted value, the unknown parameters are
estimated via constrained kalman filter. Moreover, in the estimation of the unknown parameters, the convergence of
them are also guaranteed. Finally, the advantages of the proposed method over the conventional method are shown
through actual prediction evaluations.

Short-Term Wind Power Prediction via Kalman Filter

ISHIKAWA TomokiNAMERIKAWA Toru

IEEJ International Workshop on Sensing, Actuation, and Motion Control (Nagoya, Japan) ,

2015.03

Oral presentation (general)

This paper addresses wind power prediction which is known to be a key technology in EMS(Energy Management
Systems). In recent years, an introductory expansion of renewable energy is expected and the prediction of
wind power generation is needed for taking in wind power generation. The goal of this work is to predict the amount
of generation in the next day from the past actual data and the weather forecast data of wind. In this paper, 24 hours
ahead power prediction method using a filtering theory is proposed for wind power generation. The prediction method
is a simple algorithm, the procedure of prediction consists of two steps, the data processing and the calculation of predicted values. In the data processing, in order to get the correlative data from the database, we employ JIT(Just-In-Time)
Modeling. In the calculation of predicted value, we provide the regression model for wind speed and wind power, and the
unknown parameters are estimated via constrained kalman filter. Finally, the advantages of the proposed method over the conventional method are shown through simulations.

エネルギーネットワークの分散協調制御

NAMERIKAWA Toru

第2回制御部門マルチシンポジウム (東京電機大学) ,

2015.03

Oral presentation (invited, special)

本講演では，エネルギーネットワークシステムの分散的管理・制御問題に対して，分散協調制御理論からのアプローチとして，講演者のこれまでの一連の研究成果を紹介する．具体的にはスマートグリッドの分散制御，電力市場における分散的最適価格設定法と需給制御，スマートグリッドの最適エネルギーマネジメントに関して議論するとともに，その基盤となる協調制御，分散制御に関する過去の研究についても言及する．最後に今後の研究の展望と将来の方向性を述べる．

Experimental Validation of Cooperative Formation Control with Collision Avoidance for a Multi-UAV System

KURIKI YasuhiroNAMERIKAWA Toru

Proceedings of the 6th International Conference on Automation, Robotics and Applications, 2015 (Queenstown, New Zealand) ,

2015.02

Oral presentation (general)

In this study, we consider cooperative control
issues for a multi-unmanned aerial vehicle (UAV) system.
Specifically, we present a cooperative formation control strategy for a multi-UAV system with unidirectional network links. Our strategy is to apply a consensus-based algorithm and leaderfollower structure to the UAVs so that they can cooperatively fly in formation. The leader provides each UAV with commands to generate a geometric configuration of the formation. Convergence is guaranteed when the cooperative formation control algorithm is applied to the UAVs. Collisions among UAVs can occur when they are flying with the cooperative control UAVs.
Our strategy for collision avoidance is to apply an artificial potential approach to the UAVs. Experiments are performed on multiple commercial small UAVs to validate the proposed formation control algorithm with collision-avoidance capability.

Dynamic pricing considering constraints of power grids

Okawa Yoshihiro, Namerikawa Toru

Proceedings of SICE Annual Conference,

2014.10

Oral presentation (general)

This paper deals with a model of a real-time electricity market for a smart grid, and discusses how to decide wholesale and retail prices of electricity among market participants: power consumers, power suppliers and an independent system operator. In this paper, we consider a linearized AC model of a power grid with a direct current process and show that the wholesale price for suppliers is determined as the optimal Lagrange multiplier corresponding to the nodal power balance constraints. In addition, we propose a decision procedure for the retail pricing of electricity for consumers. In order to improve the convergence speed of the algorithm, we apply the iterative gradient method with line search to a retail pricing decision procedure, in which the optimal step size is determined in each iteration step. Simulation results, finally, show the effectiveness of the proposed retail pricing decision procedure.

Fuel consumption optimization for a power-split HEV via gain-scheduled model predictive control

Iyama Hitoshi, Namerikawa Toru

Proceedings of SICE Annual Conference,

2014.10

Oral presentation (general)

In this paper, we propose a fuel consumption optimization technique for a power-split hybrid electric vehicle (HEV) via gain-scheduled model predictive control. The control algorithms for the hybrid powertrain choose the power split between the internal combustion engine and electric motor of the HEV in order to minimize the fuel consumption. The operating conditions of the HEV change during driving in real time by road conditions and driver demand. Therefore, it is necessary to have optimal control in real time and to consider the time-varying motor condition. We model an HEV and propose a gain-scheduled model predictive control for a power-split HEV. Using the proposed technique, the optimal fuel consumption for a power-split HEV is achieved. Finally, the proposed approach is validated by numerical simulations.

Hierarchical Control of Power Networks by using Overlapping Information

SUEHIRO TomoharuNAMERIKAWA Toru

14th International Conference on Control, Automation and Systems (ICCAS 2014) (KINTEX, Gyeonggi-do, Korea) ,

2014.10

Oral presentation (general)

This study deals with decentralized and hierarchical control for electric power networks by using overlapping
information. The control objective is to minimize the cost function of the load frequency control problem. The control
law consists of three steps. We apply the decentralized hierarchical control methodology to large-scale electrical power networks consisting of distributed power storage and generation sources such as batteries and wind power generators. Through several numerical simulation results of decentralized power networks, we verified their stability, compared the proposed and the previous decentralized methods, and showed the effectiveness of the proposed method.

Fuel Consumption Optimization for a Power-Split HEV via Gain-Scheduled Model Predictive Control

IYAMA HitoshiNAMERIKAWA Toru

SICE Annual Conference 2014 (Hokkaido University, Sapporo, Japan) ,

2014.09

Oral presentation (general)

In this paper, we propose a fuel consumption optimization technique for a power-split hybrid electric vehicle
(HEV) via gain-scheduled model predictive control. The control algorithms for the hybrid powertrain choose the power split between the internal combustion engine and electric motor of the HEV in order to minimize the fuel consumption.
The operating conditions of the HEV change during driving in real time by road conditions and driver demand. Therefore, it is necessary to have optimal control in real time and to consider the time-varying motor condition. We model an HEV and propose a gain-scheduled model predictive control for a power-split HEV. Using the proposed technique, the optimal fuel consumption for a power-split HEV is achieved. Finally, the proposed approach is validated by numerical simulations.

Dynamic Pricing Considering Constraints of Power Grids

OKAWA YoshihiroNAMERIKAWA Toru

SICE Annual Conference 2014 (Hokkaido University, Sapporo, Japan) ,

2014.09

Oral presentation (general)

This paper deals with a model of a real-time electricity market for a smart grid, and discusses how to decide
wholesale and retail prices of electricity among market participants: power consumers, power suppliers and an independent system operator. In this paper, we consider a linearized AC model of a power grid with a direct current process and show that the wholesale price for suppliers is determined as the optimal Lagrange multiplier corresponding to the nodal power balance constraints. In addition, we propose a decision procedure for the retail pricing of electricity for consumers.
In order to improve the convergence speed of the algorithm, we apply the iterative gradient method with line search to a
retail pricing decision procedure, in which the optimal step size is determined in each iteration step. Simulation results, finally, show the effectiveness of the proposed retail pricing decision procedure.

Consensus-based Cooperative Formation Control with Collision Avoidance for a Multi-UAV System

KURIKI YasuhiroNAMERIKAWA Toru

The 2014 American Control Conference, Portland, USA (ACC2014) (Portland, USA) ,

2014.06

Oral presentation (general)

In this paper, we study cooperative control problems
with a multi-UAV system. Specifically, we propose a c
consensus-based cooperative formation control strategy with
collision-avoidance capability for a group of multiple unmanned aerial vehicles (UAVs). To cooperatively fly in formation, a consensus-based algorithm and a leader-follower structure are applied to the UAVs. Collisions among the UAVs can occur while they are flying with the cooperative control algorithm.
Therefore, we describe how the cooperatively controlled UAVs
avoid collisions while they are flying to desired position for formation. The collision-avoidance strategy is based on an artificial potential approach. The convergence is guaranteed even when the cooperative formation control algorithm and the collision-avoidance control algorithm are simultaneously applied to the quadrotors. Finally, the proposed approach is validated by some simulations.

Consensus-based cooperative formation control with collision avoidance for a multi-UAV system

Kuriki Yasuhiro, Namerikawa Toru

Proceedings of American Control Conference,

2014

Oral presentation (general)

In this paper, we study cooperative control problems with a multi-UAV system. Specifically, we propose a c consensus-based cooperative formation control strategy with collision-avoidance capability for a group of multiple unmanned aerial vehicles (UAVs). To cooperatively fly in formation, a consensus-based algorithm and a leader-follower structure are applied to the UAVs. Collisions among the UAVs can occur while they are flying with the cooperative control algorithm. Therefore, we describe how the cooperatively controlled UAVs avoid collisions while they are flying to desired position for formation. The collision-avoidance strategy is based on an artificial potential approach. The convergence is guaranteed even when the cooperative formation control algorithm and the collision-avoidance control algorithm are simultaneously applied to the quadrotors. Finally, the proposed approach is validated by some simulations. © 2014 American Automatic Control Council.

SLAM problem via H_∞ filter with compensation for intermittent observation

Okawa Yoshihiro, Namerikawa Toru

Proceedings of 2014 IEEE 13th International Workshop on Advanced Motion Control,

2014

Oral presentation (general)

This paper deals with the Simultaneous Localization and Mapping (SLAM) problem via the H_∞ filter with compensations for intermittent observations. In order to estimate positions of a robot and landmarks accurately under intermittent observations, we propose the method with a novel filter which detects and compensates intermittent observations by comparing the obtained data with their estimations. This paper also shows the convergence of the estimated error covariance matrices. With simulation and experimental results, we confirm that the state of the robot and the environmental conditions are estimated accurately via the proposed filter under intermittent observations and that the derived theorems of the convergence are correct. © 2014 IEEE.

Interpolation for Gas Source Detection Using Parameter Estimation in a Sensor Network

S.Tokumoto T.Namerikawa

The 52nd IEEE Conference on Decision and Control2013(CDC) (Florence,Italy) ,

2013.12

Oral presentation (general), IEEE

The purpose of this research is to detect a person
with a sensor network that uses CO2 sensors and to guide a
rescue robot to the position at which the person is located. Whena person is in a position where sensors are arranged, that person can be detected, but when a person is in a position where sensors are not arranged, detection cannot be performed. Therefore,in this paper, we propose interpolating CO2 concentrations between sensors so that detection of a person can be performed in regions where sensors are not arranged. First, the wind speed required for gas concentration interpolation is estimated
from the observed sensor values. Then, the algorithm for
interpolating the CO2 concentration between sensors using the estimated wind speed is shown. Finally, the validity of the proposed method is verified by simulation.

Formation Control of UAVs with a Fourth-order Flight Dynamics

Y.Kuriki T.Namerikawa

The 52nd IEEE Conference on Decision and Control 2013(CDC) (Florence,Italy) ,

2013.12

Oral presentation (general), IEEE

In this paper, we study cooperative control problems
with a multi-UAV system expressed as a fourth-order
system using a consensus algorithm. We first show that a
linearized model of quadrotors is expressed as a fourth-order system, and then propose a formation control algorithm for the fourth-order system after formulating a problem. The proposed control law is based on a consensus algorithm and a leader-follower structure is also applied to the control law so that a leader can individually provide each of the quadrotors with information of their desired states. And then, we show that the proposed control algorithm can guarantee accurate formation keeping when fundamental assumptions about the network composed of the multiple UAVs are satisfied.
Finally, the proposed approach is validated by some simulations.

Convex Hull Pricing for Demand Response in Electricity Markets

N.Ito,A.Takeda,NAMERIKAWA Toru

IEEE Smart Grid Comm 2013 (Vancouver,Canada) ,

2013.10

Oral presentation (general), IEEE

Dynamic pricing (a.k.a. real-time pricing) is a method of invoking a response in demand pricing electricity at hourly (or more often) intervals. Several studies have proposed dynamic pricing models that maximize the sum of the welfares of consumers and suppliers under the condition that the supply and demand are equal. They assume that the cost functions of suppliers are convex. In practice, however, they are not convex because of the startup costs of generators. On the other hand,many studies have taken startup costs into consideration for unit commitment problems (UCPs) with a fixed demand. The Lagrange multiplier of the UCP, called convex hull pricing (CHP),
minimizes the uplift payment that is disadvantageous to suppliers.However, CHP has not been used in the context of demand response.
This paper presents a new dynamic pricing model based
on CHP. We apply CHP approach invented for the UCP to a
demand response market model, and theoretically show that the CHP is given by the Lagrange multiplier of a social welfare maximization problem whose objective function is represented as the sum of the customer’s utility and supplier’s profit. In addition,
we solve the dual problem by using an iterative algorithm based on the subgradient method. Numerical simulations show that the prices determined by our algorithm give sufficiently small uplift payments in a realistic number of iterations.

Game Theoretic Real-Time Pricing based on Dual Decomposition and its Application to Load Frequency Control of Power Networks

N.Okubo T.Namerikawa

Virtual Control Conference 2013 (VCC-13) (Aalborg,Denmark) ,

2013.09

Oral presentation (general)

This paper proposes a game theoretic real-time
pricing method based on dual decomposition and its application to the load frequency control of power networks. The proposed pricing method aims to solve the constrained optimization problem,which consists of each player’s utility, and social welfare under selfish players. A selfish player’s decision is a Nash equilibrium solution that considers his/her own cost function.
We show that this method can influence a selfish player’s
decision toward social welfare maximization. Finally, we show that the proposed method is effective for load frequency control on the basis of simulation results.

Optimal Battery Capacity Determination for Micro-Grid System Considering Li-ion Battery Characteristics

T.Mukai T.Namerikawa

SICE Annual Conference 2013 (Nagoya University,Nagoya,Japan) ,

2013.09

Oral presentation (general)

In this paper, the problem of determining the size of battery storage used in grid-connected photovoltaic(PV)
systems is discussed. In this problem, our goal is to find optimal capacity and charge/discharge planning for Li-ion batterys to minimize the power purchase cost. We propose a novel charge/discharge planning method based on optimization
technique considering Li-ion battery characteristics to expand battery life. Finally, the effectiveness of the proposed method is shown via simulations.

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

Y.Tachibana T.Namerikawa

SICE Annual Conference 2013 (Nagoya University,Nagoya,Japan) ,

2013.09

Oral presentation (general)

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.

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

T.Kojima and T.Namerikawa

SICE Annual Conference 2013 (Nagoya University,Nagoya,Japan) ,

2013.09

Oral presentation (general)

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.

Optimal Pricing Algorithm Based on Steepest Descent Method for Electricity Market with Battery and Accumulator

Y.MiyanoT.Namerikawa

2013 Internatonal Symposium on Nonlinear Theory and its Applications(NOLTA) (Santa Fe,USA) ,

2013.09

Oral presentation (general)

This paper considers a day-ahead market with batteries and accumulators to level power generation.
First, we model a consumer with battery, a generator with
battery, and an accumulator that each act to maximize their
own profit. Then, we not only propose the optimal pricing
algorithm based on dual decomposition and the steepest descent method but also prove the stability of this algorithm.
Finally, we demonstrate the effectiveness of the algorithm
through some numerical simulation.

Short-TermWind Power Prediction forWind Turbine via Kalman Filter based on JIT Modeling

T.IshikawaT.Namerikawa

SICE Annual Conference 2013 (Nagoya university,Nagoya,Japan) ,

2013.09

Oral presentation (general)

This paper addresses wind power prediction which is known to be a key technology in EMS(Energy Management Systems). In recent years, an introductory expansion of renewable energy is expected and the prediction of wind power generation is needed for taking in wind power generation. The goal of this work is to predict the amount of generation in the next day from the past actual data and the weather forecast data of wind. In this paper, 24 hours
ahead power prediction method using a filtering theory is proposed for wind power generation. The prediction method
is a simple algorithm, the procedure of prediction consists of two steps, the data processing and the calculation of predicted values. In the data processing, in order to get the correlative data from the database, we employ JIT(Just-In-Time) Modeling. In the calculation of predicted value, we provide the regression model for wind speed and wind power, and the unknown parameters are estimated via constrained kalman filter. Finally, the advantages of the proposed method over the conventional method are shown through simulations.

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

Y.Okawa T.NAMERIKAWA

SICE Annual Conference 2013 (Nagoya University,Nagoya,Japan) ,

2013.09

Oral presentation (general)

This paper deals with the simultaneous localization and mapping (SLAM) problem via the H∞ 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∞ 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.

Consensus-based Cooperative Control for Geometric Configuration of UAVs Flying in Formation

Y.kuriki and T.Namerikawa

SICE Annual Conference 2013 (Nagoya University,Nagoya,Japan) ,

2013.09

Oral presentation (general)

In this paper, we study cooperative control problems with a multi-UAV system expressed as a first-order system. Specifically, we describe a problem that cooperatively controlled UAVs change geometric configuration between
multiple UAVs while the UAVs are flying in formation. In other words, each of the UAVs must intensionally change
relative position between the UAV and the leader while the UAVs are cooperatively controlled. We propose a control
algorithm to change geometric configuration among the UAVs arbitrarily while the cooperatively controlled UAVs are
flying in formation. The control algorithm is based on a consensus algorithm. A leader-follower structure is also applied to provide the UAVs with commands from a leader. The control algorithm has an advantage in finding a controller gain to stabilize the multi-UAV system. In addition, the convergence speed does not depend on the network structure of the system. Finally, the proposed approach is validated by some simulations.

Distributed Model Predictive Control of Load Frequency of Power Network

C.Fogelberg NAMERIKAWA Toru

SICE Annual Conference 2013 (Nagoya University,Nagoya,Japan) ,

2013.09

Oral presentation (general)

Passivity and RISE based Robust Control for Bilateral Teleoperation System with Communication Delay

Y.Kawai and T.Namerikawa

2013 IEEE Multiconference on Systems and Control(MSC) (Hyderabad,India) ,

2013.08

Oral presentation (general)

In this paper, a method for passivity- and robust integral of the sign of the error (RISE)-based control of a nonlinear teleoperation system with communication delays is
proposed. This control strategy can accurately achieve coordinate positioning under conditions with viscous friction and unmodeled effects compensation errors, and its stability condition is independent of robot model parameter uncertainties and time delay. Using passivity-based stability analysis, the stability and tracking performance of this system are demonstrated, and experimental trials are performed to verify its effectiveness.

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

Y.Fujita,T.Namerikawa and K.Uchida

2013 European Control Conference (ECC) (Zurich,Switzerland) ,

2013.07

Oral presentation (general)

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.

データに基づく電力需要／発電予測、デマンドレスポンスと最適化、分散・予測・最適制御

NAMERIKAWA Toru

分散型電源の最適制御・運用技術とそのポイント,

2013.05

Oral presentation (invited, special), 日本テクノセンター

エネルギー問題や地球温暖化は世界的な課題であり、省エネルギー、コスト削減の観点から世界中で太陽光発電や風力発電バイオマス発電、コージェネレーションなどの分散型電源が大量に電力系統に連系されようとしています。導入自体は地球環境保護の観点からは好ましいことですが、分散型再生可能エネルギーを本格的に導入するためには、大規模・複雑化していくシステムをどのような形態で接続するべきかという電力ネットワークトポロジーの視点から、電力システムの安定性、最適性、経済性を再考する必要が生じます。
本講習会では、このような分散型電源の大量導入に伴う問題や、それらの管理・最適制御・運用技術とその最先端の研究動向について、分かり易く講義します。

Game Theoretic Real-Time Pricing and its Application to Power Networks

Toru NAMERIKAWA

UF NCR Seminar,

2013.03

Oral presentation (invited, special), Nonlinear Control & Robotics, University of Florida

A control problem of power network systems including renewable energy generators is one of the hottest issues in the world. This talk deals with a game theoretic real-time pricing method based on dual decomposition and its application to load frequency control of electrical power networks. The goal of this real-time pricing methodology is to solve the constrained optimization problem consist of each players' utility and social welfare under selfish players. We can show that selfish players‘ decision can be expressed via a kind of a Nash equilibrium solution considering their own cost functions and it can lead selfish players‘ decision to social welfare maximization. Finally the proposed method is applied to a load frequency control problem of power networks and the effectiveness can be shown via some numerical simulation results.

デマンドレスポンスと再生可能エネルギーを含む分散型大規模電力ネットワークの最適運用

Toru NAMERIKAWA

トリケップス　セミナー,

2013.03

Oral presentation (invited, special), (株）トリケップス

Real-Time Pricing and its Application to Load Frequency Control of Power Networks

Toru NAMERIKAWA

UCSB CCDC 2013 Winter Seminar,

2013.01

Oral presentation (invited, special), UCSB CCDC

A control problem of power network systems including renewable energy generators is one of the hottest issues in the world. This talk deals with a game theoretic real-time pricing method based on dual decomposition and its application to load frequency control of electrical power networks. The goal of this real-time pricing methodology is to solve the constrained optimization problem consist of each players' utility and social welfare under selfish players. We can show that selfish players' decision can be expressed via a kind of a Nash equilibrium solution considering their own cost functions and it can lead selfish players' decision to social welfare maximization. Finally the proposed method is applied to a load frequency control problem of power networks and the effectiveness can be shown via some numerical simulation results.

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

K.Kosugi, S.Tokumoto and T.NAMERIKAWA

2012 51th IEEE Conference on Decision and Control (Maui, Hawaii, USA) ,

2012.12

Oral presentation (general), IEEE Control Systems Society

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.

再生可能エネルギーを含む分散型エネルギー管理システムの需給制御

NAMERIKAWA Toru

ＴＩＣセミナー,

2012.10

Oral presentation (invited, special), 技術情報センター

エネルギーの効率利用に向け、デマンドレスポンスに関する研究開発が進展しています。本セミナーでは、デマンドレスポンスとエネルギーマネジメント技術に焦点をあて、「デマンドレスポンスを活用した次世代の電力システム」、「マイクログリッド制御とデマンドレスポンスを一体化したエネルギーマネジメント技術」、「電力ピークを回避するデマンドレスポンスとスマートメーターシステム」、「再生可能エネルギーを含む分散型エネルギー管理システムの需給制御」について、斯界の第一線でご活躍中の講師陣に詳説頂きます。

Robot Localization and Mapping Problem with Bounded Noise Uncertainties

Hamzah Ahmad and Toru NAMERIKAWA

Proc. of 2012 IEEE Symposium on Industrial Electronics and Applications (Bandung, Indonesia) ,

2012.09

Oral presentation (general), IEEE Industrial Electronics Society

This paper deals with H∞ 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 γ and initial state covariance matrix in H∞ Filter, the estimation results can show better performance in comparison to the Kalman Filter approach. From the analysis of convergence properties of H∞ Filter, it is found that the filter is capable to provide a reliable estimation. Besides, from the simulation results, H∞ 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.
Category

次世代エネルギーシステム設計に向けて

NAMERIKAWA Toru

SICE Annual Conference 2012 併設特別企画,

2012.08

Oral presentation (invited, special), The Society of Instrument and Control Engineers

スマートグリッドのための分散予測制御

NAMERIKAWA Toru

SICE九州フォーラム 2012,

2012.08

Oral presentation (invited, special), 計測自動制御学会九州支部

本講演では，再生可能エネルギーを含む分散型エネルギーネットワークの分散制御問題に関して，分散型制御方策と予測型制御方策を紹介する．具体的には多くのサブシステムを持つ階層型の大規模システムに対する分散制御問題に対して，情報結合構造を共分散拘束として表現するアプローチや，反復勾配法などの最適化手法，モデル予測制御について議論する．更には電力需要のピーク電力を抑えるための方策として，動的かつ柔軟に電力価格を変更するリアルタイムプライシングに対するアプローチの動向についても解説する．

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

Yasuhiko Hosoda NAMERIKAWA Toru

SICE Annual Conference 2012 Akita University (Akita University,Akita,Japan) ,

2012.08

Oral presentation (general), The Society of Instrument and Control Engineers

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∞ filtering. The effectiveness of the proposed prediction method is demonstrated through numerical simulations.

Load Leveling Control by Real-Time Dynamical Pricing Based on Steepest Descent Method

Yuki Miyano NAMERIKAWA Toru

SICE Annual Conference 2012 Akita University (Akita University,Akita,Japan) ,

2012.08

Oral presentation (general), The Society of Instrument and Control Engineers

This paper describes load leveling control by Real-Time Dynamical pricing based on optimization method. First, we propose a profit maximization problem of supply and demand, satisfying the supply constraint and the balancebetween supply and demand. Then we rewrite them to dual problem which minimizes electricity price. We madealgorithm to solve the dual problem by Steepest Descent Method and proof its convergence. Finally some numerical simulations show the effectiveness of the proposed load leveling control.

Decentralized Control of Smart Grid by using Overlapping Information

Tomoharu Suehiro NAMERIKAWA Toru

SICE Annual Conference 2012 Akita University (Akita University,Akita,Japan) ,

2012.08

Oral presentation (general), The Society of Instrument and Control Engineers

Abstract: 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.

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

Toru Namerikawa and Taichiro Kato

2011 50th IEEE Conference on Decision and Control and European Control Conference (CDC-ECC) (Orlando, FL, USA) ,

2011.12

Oral presentation (general), IEEE Control Systems Society

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.

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

Nam Duc Do and Toru Namerikawa

2011 50th IEEE Conference on Decision and Control and European Control Conference (CDC-ECC) (Orlando, FL, USA) ,

2011.12

Oral presentation (general), IEEE Control Systems Society

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.

再生可能エネルギーを含む分散型エネルギーシステムの分散制御（招待講演）

NAMERIKAWA Toru

制御技術フォーラム,

2011.11

Oral presentation (invited, special), 計測自動制御学会制御部門制御技術部会

Distributed and Cooperative Control of Distributed Energy Systems with Renewable Energy Generators（Invited Talk）

Toru NAMERIKAWA

Korea Railroad Research Institute (Korea Railroad Research Institute) ,

2011.10

Oral presentation (invited, special), Korea Railroad Research Institute

Distributed and Cooperative Control of Distributed Energy Systems with Renewable Energy Generators（Invited Talk）

Toru NAMERIKAWA

Seoul National University (Seoul National University) ,

2011.10

Oral presentation (invited, special), Seoul National University

Predictive Control and Estimation for Systems with Information Structured Constraints

Toru Namerikawa, Takeshi Hatanaka and Masayuki Fujita

2011 11th ICCAS (KINTEX, Gyeonggi-do, Korea) ,

2011.09

Oral presentation (general), The Society of Instrument and Control Engineers

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.

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

Taichiro Kato and Toru Namerikawa

SICE Annual Conference 2011 (Waseda University) ,

2011.09

Oral presentation (general), The Society of Instrument and Control Engineers

This paper deals with a distributed control for load frequency of power networks based on iterative gradient methods.
The control objective is to minimize the quadratic cost function ofload frequency control problem, and we apply this distributed control methodology to complicated large scale electrical power networks by using iterative gradient methods. Finally,simulation results of distributed large scale power network systems including distributed generations, batteries, and renewable energies in order to show the effectiveness of the load frequency control compared with decentralized control and centralized control.

Dynamic Target Navigation based on Multisensor Kalman Filtering and Neighbor Discovery Algorithm

Kazuya Kosugi and Toru Namerikawa

SICE Annual Conference 2011 (Waseda University) ,

2011.09

Oral presentation (general), The Society of Instrument and Control Engineers

This paper deals with an estimate algorithm which considers optimal control input for dynamic target navigation by using wireless sensor networks and distributed Kalman filter. We propose a novel sensor scheduling algorithm based on a neighbor discovery algorithm for discrete-time linear time-invariant systems. Then we propose an estimate algorithm by sharing predicted estimate values and analyze characteristic of this algorithm. Finally, experimental results show effectiveness of the proposed method in sensor networked feedback systems.

Experiments on Transportation Support System using Multi-Vehicle's Formation

Yasunori Kawai, Kentarou Nagashima and Toru Namerikawa

SICE Annual Conference 2011 (Waseda University) ,

2011.09

Oral presentation (general), The Society of Instrument and Control Engineers

Cooperative Conveyance by Vehicle Swarms with Dynamic Network Topology

Koji Ishimura and Toru Namerikawa

SICE Annual Conference 2011 (Waseda University) ,

2011.09

Oral presentation (general), The Society of Instrument and Control Engineers

This paper deals with cooperative conveyance control by vehicle swarms with dynamic network topology. First, we introduce a dynamic network topology that depends on relative distance between the vehicles. Secondly, we propose a novel conveyance strategy based on consensus seeking with dynamic network topology. The proposed strategy needs at least one vehicle which can acquire the information of the target-object and network topology among vehicles is time-varying but always connected. Furthermore the strategy is composed of Surround and Transport mode. To analyze the convergence of conveyance with dynamic network topology, algebraic graph theory and matrix theory are utilized. Finally, numerical simulation results demonstrate the effectiveness of the proposed method.

Synchronization Condition of Power Networks by Using Non-Uniform Kuramoto Model

Y. Fujita #HT. Namerikawa

2011 International Symposium on Nonlinear Theory and Applications (kobe,Japan) ,

2011.09

Oral presentation (general), The Institute of Electronics, Information and Communication Engineers

This paper discusses the synchronization
problem and it’s solutions for large scale power network
systems. We analyze dynamical properties of power networks
and derive the synchronization condition of electrical
generators. First, we employ a termed Kron reduction
method to derive swing equation, which describes states
of generators. Second, the derived equation is reduced
into Non-uniform Kuramoto model, and then, a synchronization
condition is derived by using the reduced model.
Finally, we have succeed in relaxing the synchronization
condition by controlling power units. Effectiveness of the
proposed condition is shown via numerical control simulations.

環境エネルギーに貢献するシステム制御 (解説)

NAMERIKAWA Toru

CYBERNET NEWS,

2011.09

Other, サイバネットシステム

H∞ Filter-SLAM:A Sufficient Condition for Estimation

HAMZAH Ahmad NAMERIKAWA Toru

Preprints of 18th IFAC World Congress (Milano Italy) ,

2011.09

Oral presentation (general), International Federation of Automatic Control

A theoretical study about HFilter based SLAM is proposed to propose a sufficient condition
for estimation purposes. Two different cases of initial state covariance are given and analyzed to obtain
a best solution for SLAM problem with consideration of process and measurement noises statistical
behavior. If the proposed conditions are not satisfied during estimation, then the estimation will exhibit
unbounded uncertainties and consequently result in erroneous inference. Simulation results demonstrates
the performance as what this paper suggested on the theoretical analysis. These results consistently
supports and guarantees our previous findings.

再生可能エネルギーと分散協調制御（招待講演）

NAMERIKAWA Toru

JST研究開発戦略センター (未入力) ,

2011.08

Other

再生可能エネルギーを本格的に導入するためには，大規模・複雑化していくシステムをどのような形態で接続するかというネットワークトポロジーの視点から，電力システムの安定性・最適性のための協調分散制御などの理論や構造設計論が必要である．
また環境に依存した不安定な属性を持つ再生可能エネルギーから引き出す電力品質（周波数・電圧など）の確保のために，再生可能エネルギー源と蓄電池の組合せに予測制御を施すことにより，安定化する必要がある．
本講演では，これらの課題に対して，最新の分散協調制御理論についてご紹介する．

Covariance Inflation Efficiency in H∞ Filter Based SLAM

H. Ahmad and T. Namerikawa

Proc of International Conference on Electrical, Control and Computer Engineering (Kuantan,Malaysia) ,

2011.06

Oral presentation (general)

本論文は自律移動ロボットの自己位置推定と地図作成問題(SLAM)に対して，位置センサの確率的振舞が未知の場合に対して，H∞フィルタを用いて推定誤差の解析を行った．ここでは特に共分散膨張法を用いることにより，位置推定精度を向上させ，誤差共分散行列の漸近的収束性を証明した．更には，小型移動ロボット用いた実時間制御実験により，理論解析の有効性を実験的に示すとともに，SLAM問題に対してH∞フィルタと共分散膨張法の有用性も実証した．

EKF based SLAM with FIM Inflation

H. Ahmad and T. Namerikawa

Proc of the 2011 Asian Control Conference (Kaohsiung,Taiwan) ,

2011.05

Oral presentation (general)

本論文は自律移動ロボットの自己位置推定と地図作成問題(SLAM)に対して，特に通信環境の変動により計測データが断続的に得られる場合において，拡張カルマンフィルタを用いて自己位置推定した場合の位置推定誤差の上下限をフィッシャー情報行列を用いて算出する方法を提案している．具体的には仮に計測データが届かない場合でもFIMを用いることで，誤差共分散の上下限が与えられることを理論的に証明している．最後に数値シミュレーションにっより提案法の有効性を検証している．

Energy Network and Control Theory

NAMERIKAWA Toru

制御フォーラム第２回公開フォーラム (日本鉄鋼協会) ,

2011.04

Oral presentation (invited, special), 日本鉄鋼協会計測・制御・システム工学部会

Cooperative conveyance by vehicle swarms with dynamic network topology

Ishimura Koji, Namerikawa Toru

SICE Annual Conference 2011,

2011

Oral presentation (general)

This paper deals with cooperative conveyance control by vehicle swarms with dynamic network topology. First, we introduce a dynamic network topology that depends on relative distance between the vehicles. Secondly, we propose a novel conveyance strategy based on consensus seeking with dynamic network topology. The proposed strategy needs at least one vehicle which can acquire the information of the target-object and network topology among vehicles is time-varying but always connected. Furthermore the strategy is composed of Surround and. Transport mode. To analyze the convergence of conveyance with dynamic network topology, algebraic graph theory and matrix theory are utilized. Finally, numerical simulation results demonstrate the effectiveness of the proposed method. © 2011 SICE.

Covariance inflation efficiency in H_∞ filter based SLAM

Ahmad Hamzah, Namerikawa Toru

International Conference on Electrical, Control and Computer Engineering 2011 (InECCE),

2011

Oral presentation (general)

This paper analyzes the performance of H_∞ Filter(HF) based SLAM(Simultaneous Localization and Mapping) by applying the Covariance Inflation method. We show that via Covariance Inflation, the updated state error covariance matrix is restrictively depends on the number of decorrelated landmarks such as if smaller number of landmarks are being decorrelated from other landmarks, then the decorrelated landmarks has smaller covariance than the correlated landmarks. Even more, HF with Covariance Inflation shows better confidence regarding its estimation in comparison with EKF with Covariance Inflation if the initial state covariance and measurement noise are big. The results are evaluated through several simulation analysis and consistently supports our claims. © 2011 IEEE.

Predictive control and estimation for systems with information structured constraints

Namerikawa Toru, Hatanaka Takeshi, Fujita Masayuki

2011 11th International Conference on Control, Automation and Systems,

2011

Oral presentation (general)

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. © 2011 ICROS.

H _∞Filter-SLAM

Ahmad Hamzah, Namerikawa Toru

18th IFAC World Congress,

2011

Oral presentation (general)

A theoretical study about H _∞Filter based SLAM is proposed to propose a sufficient condition for estimation purposes. Two different cases of initial state covariance are given and analyzed to obtain a best solution for SLAM problem with consideration of process and measurement noises statistical behavior. If the proposed conditions are not satisfied during estimation, then the estimation will exhibit unbounded uncertainties and consequently result in erroneous inference. Simulation results demonstrates the performance as what this paper suggested on the theoretical analysis. These results consistently supports and guarantees our previous findings. © 2011 IFAC.

Cooperative control based on Force-Reflection with four-channel teleoperation system

Duc Do Nam, Namerikawa Toru

2011 50th IEEE Conference on Decision and Control and European Control Conference,

2011

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. © 2011 IEEE.

Demand Prediction and Distributed Control of Power Grid

Toru Namerikawa

SICEプラントモデリング部会第2回オープンフォーラム (東京工業大学) ,

2010.12

Oral presentation (invited, special), SICEプラントモデリング部会

Four-channel Force Reflecting Teleoperation System Based on ISS Small Gain Theorem

Nam Duc Do and Toru Namerikawa

MECATRONICS2010-Yokohama (Keio University) ,

2010.11

Oral presentation (general), JSPE Technical Committee on Industrial Application of Image Processing

H-infinity Filter-based Robotic Localization and Mapping with Intermittent Measurements

Hamzah Ahmad and Toru Namerikawa

MECATRONICS2010-Yokohama (Keio University) ,

2010.11

Oral presentation (general), JSPE Technical Committee on Industrial Application of Image Processing

Multi-Agent Systems and Optimal Sensor Scheduling

Toru Namerikawa

第8回安全・安心な社会を支える運動と振動の制御研究分科会 (慶應義塾大学) ,

2010.10

Oral presentation (invited, special), 日本機械学会

Demand Prediction and Distributed Control of Power Grid

Toru Namerikawa

JST/CRDS制御システム分科会―SICE 合同ワークショップ (JST研究開発戦略センター) ,

2010.10

Oral presentation (invited, special), JST研究開発戦略センター

Bilateral Teleoperation of Multiple Cooperative Robots with Time-Varying Delay

Nam Duc Do, Yusuke Yamashina and Toru Namerikawa

2010 IEEE Multi-conference on Systems and Control (Yokohama, Japan) ,

2010.09

Oral presentation (general), The Institute of Electrical and Electronics Engineers (IEEE)

10911940397120110430173914PDF1.pdf

Electric Demand Prediction and Predictive Control of Micro Grid

Toru Namerikawa

2010 IEEE Multi-conference on Systems and Control (Yokohama, Japan) ,

2010.09

Oral presentation (invited, special), The Institute of Electrical and Electronics Engineers (IEEE)

10911940394220110430180401PDF1.pdf

Robot Localization and Mapping Problem with Unknown Noise Characteristics

Hamzah Ahmad and Toru Namerikawa

2010 IEEE Multi-conference on Systems and Control (Yokohama, Japan) ,

2010.09

Oral presentation (general), The Institute of Electrical and Electronics Engineers (IEEE)

10911940397120110430173914PDF1.pdf

Bilateral Teleoperation of Wheeled Mobile Robot with Time Delay Using Virtual Image Robot

Yasunori Kawai, Toru Namerikawa and Masayuki Fujita

2010 IEEE Multi-conference on Systems and Control (Yokohama, Japan) ,

2010.09

Oral presentation (general), The Institute of Electrical and Electronics Engineers (IEEE)

10911940396220110430173052PDF1.pdf

Sensor Network Scheduling Algorithm Considering Estimation Error Variance and Communication Energy

Takashi Takeda and Toru Namerikawa

2010 IEEE Multi-conference on Systems and Control (Yokohama, Japan) ,

2010.09

Oral presentation (general), The Institute of Electrical and Electronics Engineers (IEEE)

10911940397120110430173914PDF1.pdf

システム制御でエネルギーの未来を拓く:制御理論による風力発電とスマートグリッド（招待講演）

早川朋久，滑川徹

2010 年IEEE システムと制御に関する合同会議 (Yokohama.Japan) ,

2010.09

Oral presentation (invited, special)

2010 IEEE MSC （システムと制御に関する合同会議）において，本会議併設行事として，広く，公開市民講座を開催した．具体的にはH∞フィルタに基づく電力需要予測とマイクログリッドの分散予測制御について述べた．需要予測のためにH∞フィルタを用いて電力需要特性のパラメータ推定を行い，これによって, モデル化誤差に対し，より正確な推定が可能となったことを平易に解説した．さらに実際の運用を想定し平日と休日の需要曲線の特徴を考慮した電力需要予測手法について詳しく説明した．

A Sensor Network Configuration Considering Priori Estimation Error and Communication Energy

Takashi Takeda and Toru Namerikawa

12th IFAC LSS Symposium (Lille, France) ,

2010.07

Oral presentation (general), The International Federation of Automatic Control (IFAC)

10911940393720110430170652PDF1.pdf

Feasibility Study of Partial Observability in H-infinity Filtering for Robot localization and Mapping Problem

Hamzah Ahmad and Toru Namerikawa

2010 American Control Conference (Baltimore, MD, USA) ,

2010.07

Oral presentation (general), American Automatic Control Council

10911940392720110430164458PDF1.pdf

Consensus Algorithm and Cooperative Target-enclosing Strategy for Multiple Vehicles

Toru Namerikawa

SICE 第27回誘導制御シンポジウム (東京都市大学) ,

2010.05

Oral presentation (invited, special), 計測自動制御学会

Electric Load Prediction and Distributed Predictive Control of Micro Grid

Toru Namerikawa

Focus Period 2: Distributed Decisions via Games and Price Mechanisms (Lund University) ,

2010.03

Oral presentation (invited, special), Lund Center for Control of Complex Engineering Systems

A sensor network configuration considering priori estimation error and communication energy

Takeda Takashi, Namerikawa Toru

12th IFAC Symposium on Large Scale Systems: Theory and Applications,

2010

Oral presentation (general)

This paper deals with a network configuration considering priori estimation error variance and communication energy in sensor networked feedback system. Each sensor transmits information to a fusion center via multi-hop communication network. We propose a novel network configuration algorithm that each sensor node transmits information with a same dimension. The transmitted information is merged in each sensor node and consists of measurement data with time delay. Then the priori estimate can be minimum variance estimation. The proposed algorithm achieves sub-optimal network topology with minimum energy and a desired variance. Experimental results show an effectiveness of the proposed method.

Feasibility study of partial observability in H_∞ filtering for robot localization and mapping problem

Ahmad Hamzah, Namerikawa Toru

2010 American Control Conference,

2010

Oral presentation (general)

This paper presents H_∞ Filter SLAM, which is also known as the minimax filter to estimate the robot and landmarks location with the analysis on partial observability. Some convergence conditions are also presented to aid the analysis. Due to SLAM is a controllable but unobservable problem, it's difficult to estimate the position of robot and landmarks even though the control inputs are given to the system. As a result, Covariance Inflation which is a method of adding a pseudo positive semidefinite(PsD) matrix is proposed as one approach to analyze Partial Observability effects in SLAM and to reduce the computation cost. H_∞ Filter is capable of withstand non-gaussian noise characteristics and therefore, may provide another available approach towards SLAM solution. © 2010 AACC.

Sensor network scheduling algorithm considering estimation error variance and communication energy

Takeda Takashi, Namerikawa Toru

2010 IEEE International Conference on Control Applications,

2010

Oral presentation (general)

This paper deals with a sensor scheduling algrithm considering estimation error variance and communication energy in sensor networked feedback systems. We propose a novel decentralized estimation algorithm with unknown inputs in each sensor node. Most existing works deal with the sensor network systems as sensing systems and it is difficult to apply them to the real physical feedback control systems Then some local estimates are merged and the merged estimates can be optimized in the proposed method and the estimation error covariance has a unique positive definite solution under some assumptions. Next, we propose a novel sensor scheduling algorithm in which each sensor node transmits information. A sensor node uses energy by communication between other sensor node or the plant. The proposed algorithm achieves a sub-optimal network topology with minimum energy and a desired variance. Experimental results show an effectiveness of the proposed method. © 2010 IEEE.

Bilateral teleoperation of multiple cooperative robots with time-varying delay

Do Nam Duc, Yamashina Yusuke, Namerikawa Toru

2010 IEEE International Conference on Control Applications,

2010

Oral presentation (general)

This paper deals with a passive-decomposition based control of bilateral teleoperation between a single master robot and multiple cooperative slave robots under time varying delay in the communication line. At first, we decompose the dynamics of multiple slave robots into two decoupled dynamics: the Shape-System describing dynamics of the cooperative works, and the Locked-System representing overall behavior of the multiple slave robots. Second, we propose a PD control method for bilateral teleoperation to guarantee the asymptotical stability of the system for time varying delay. Finally, experimental results show the effectiveness of our proposed teleoperation. © 2010 IEEE.

Robot localization and mapping problem with unknown noise characteristics

Ahmad Hamzah, Namerikawa Toru

2010 IEEE International Conference on Control Applications,

2010

Oral presentation (general)

In this paper, we examine the H? ?Filter-based SLAM especially about its convergence properties. In contrast to Kalman Filter approach that considers zero mean gaussian noise, H_∞ Filter is more robust and may provide sufficient solutions for SLAM in an environment with unknown statistical behavior. Due to this advantage, H_∞ Filter is proposed in this paper, to efficiently estimate the robot and landmarks location under worst case situations. H_∞ Filter requires the designer to appropriately choose the noise's covariance with respect to γ to obtain a desired outcome. We show some of the conditions to be satisfy in order to achieve better estimation results than Kalman Filter. From the experimental results, H_∞Filter performs better than Kalman Filter for a case of bigger robot initial uncertainties. Subsequently, this proved that H _∞ Filter can provide another available estimation method for especially in SLAM. © 2010 IEEE.

Bilateral Control with Constant Feedback Gains for Teleoperation with Time Varying Delay

NAMERIKAWA Toru

Joint 48th IEEE Conference on Decision and Control and 28th Chinese Control Conference (Shanghai, P.R. China) ,

2009.12

Oral presentation (general), IEEE Control Systems Society

This paper describes a bilateral control of nonlinear
teleoperation with time varying communication delay.
The proposed method are simple PD-type controllers which
are independent of the rate of time delay change and depend
on the upper bound of round-trip delay. The proposed control
strategy is independent of parameter uncertainties of the model of the robots and the operator and remote environment. The delay-dependent stability of the origin is shown via Lyapunov stability theorem. Furthermore the proposed strategy also achieves master-slave position coordination and bilateral static force reflection.
Several experimental results with wireless communication
and the Internet show the effectiveness of our proposed strategy.

10911937617520100411210613PDF1.pdf

Control Theoretic Approach to Environmental Problems

NAMERIKAWA Toru

SICEセミナー「実践的な制御系設計」予測・分散・協調の制御：環境への貢献を目指して (Japan) ,

2009.12

Oral presentation (invited, special), 計測自動制御学会制御部門

サステイナブルな社会の実現のために，限りある資源を有効利用し，地球温暖化を防止する計測制御技術の開発が求められている．一方で産業の発展と快適な社会の持続のためには，エネルギーの安定確保と供給が必要とされる．
　本講義では「環境計測技術」と「エネルギー供給技術」のための分散協調制御理論とセンサスケジューリングに関する国内外の趨勢を紹介し，この分野における制御理論の貢献の可能性を概観する．

Networked Robotics and Systems and Control Theory

NAMERIKAWA Toru

SICE四国支部講演会 (Japan) ,

2009.11

Oral presentation (invited, special), SICE四国支部

Impedance Control for Force - Reflecting Teleoperation with Communication Delays Based on IOS Small Gain Theorem

DO Duc Nam and NAMERIKAWA Toru

ICROS-SICE International Joint Conference 2009 (Fukuoka International Congress Center, Japan) ,

2009.08

Oral presentation (general), ICROS-SICE

This paper focuses on a new proposal system input of impedance control that relates to force reflection (FR)
scheme of teleoperation with time varying in communication lines. To improve the tracking performance and transparency,
the control algorithm uses one more communication channel to transfer the FR information from the master side to the
slave side. Using variable damping values, the contact stability is achieved at the time while the slave robot contacts with the environment. In this work, the input-to-output stability (IOS) small gain approach is used to show the overall force-reflecting teleoperation to be input-to-state stable (ISS). Several experimental results show the effectiveness of our proposed algorithm.

10911937618820100411222748PDF1.pdf

H∞ filtering Convergence and It's Application to SLAM

AHMAD Hamzah and NAMERIKAWA Toru

ICROS-SICE International Joint Conference 2009 (Fukuoka International Congress Center, Japan) ,

2009.08

Oral presentation (general), ICROS-SICE

KF-SLAM(Kalman filter-SLAM) have been used as a popular solution by researchers in many SLAM application.
Nevertheless, it shortcomings of assumption for Gaussian noise limited its efficiency and demand researcher to consider better filter and algorithm to achieve a promising result of estimation. In this paper, we proposed one of its
family, the H∞ filter-based SLAM to determine its competency for SLAM problem. Unlike Kalman filter, H∞ filter able to work in an unknown statistical noise behavior and thus more robust. It rely on a guess that the noise is in bounded energy and does not require a priori knowledge about the system. Therefore, we proposed the H∞ filter as other available technique to infer the location for both robot and landmarks while simultaneously building the map. From the results of simulation, H∞ filter produces better outcome than the Kalman filter especially in the linear case estimation. As a result, H∞ filter may provides another available estimation methods with the capability to ensure and improve estimation for the robotic mapping problem especially in SLAM.

10911937618420100411222352PDF1.pdf

GIMC Structure based Anti-Windup Control Considering L2 Performance

NAKASHIMA Yusuke and NAMERIKAWA Toru

2009 IEEE Multi-conference on Systems and Control (Saint Petersburg, Russia) ,

2009.07

Oral presentation (general), IEEE Control Systems Society

This paper deals with GIMC (Generalized Internal Model Control) structure based Anti-Windup (AW) control system design.
First, we setup a L2 performance criterion based on GIMC structure for Anti-Windup control problems. The design problem is formulated as an optimization problem with a parameter Q. Then we calculate the optimization problem and find an optimal Q. Finally, the effectiveness of proposed method is shown by experimental results for a magnetic suspension system.

10911937618120100411215801PDF1.pdf

Delay-Independent Stabilization for Teleoperation with Time Varying Delay

FUJITA Hiroyuki and NAMERIKAWA Toru

2009 American Control Conference (St. Louis, MO, USA) ,

2009.06

Oral presentation (general), American Automatic Control Council

This paper deals with the stability for nonlinear
teleoperation with time varying communication delays. The proposed method is passivity-based controllers with time varying gains which depend on the rate of change of time varying delay.
In our proposed method, stability condition is independent of the magnitude of the communication delay and the damping
of the system. The delay-independent stability is shown via
Lyapunov stability methods. Several experimental results show the effectiveness of our proposed teleoperation.

Cooperative Target-capturing Strategy for Multi-vehicle Systems with Dynamic Network Topology

KAWAKAMI Hiroki and NAMERIKAWA Toru

2009 American Control Conference (St. Louis, MO, USA) ,

2009.06

Oral presentation (general), American Automatic Control Council

This paper deals with cooperative target-capturing
problem for multi-vehicle systems with dynamic network topology.
Firstly, we introduce a dynamic network topology that depends on relative distance between the vehicles. Secondly,
we propose the target-capturing strategy based on consensus
seeking with dynamic network topology. In proposed strategy,
at least one vehicle can acquire the information of the targetobject and network topology among vehicles is time-varying but always connected. To analyze the convergence of targetcapturing behavior with dynamic network topology, algebraic graph theory and matrix theory are utilized. Finally, numerical simulation results and experimental results are provided that demonstrate the effectiveness of the proposed method.

Stability and Tracking Properties in Predictive Control with Adaptation for Bilateral Teleoperation

YOSHIDA Kouei and NAMERIKAWA Toru

2009 American Control Conference (St. Louis, MO, USA) ,

2009.06

Oral presentation (general), American Automatic Control Council

This paper deals with an environment estimation based predictive control for teleoperation with communication time delay. In this predictive control framework, the delayed position tracking and non-delayed force reflection are attempted.
The goal of this paper is to propose a new control method
which guarantees the stability, the convergence of position
tracking error to zero and the small force tracking error
theoretically. Proposed control structure is the 3ch architecture with environment estimation based force prediction. In this proposed method, the master controller implements force control with environmental force prediction while the slave controller implements position and force control. The theoretical analysis shows the stability, the convergence of position error to zero
and the small force tracking error. Experimental results show the effectiveness of the proposed method.

Cooperative Control for Networked Teleoperation Systems with Communication Delay

NAMERIKAWA Toru

制御フォーラム「鉄鋼プロセス制御への先端的アプローチ」,

2009.05

日本鉄鋼協会計測・制御・システム工学部会

GIMC構造に基づく高性能ロバスト制御と耐故障制御（招待講演，学会セミナー講師）

NAMERIKAWA Toru

SICEセミナー　ロバスト制御　－基礎の基礎から設計の勘所まで－ (Chofu,Japan) ,

2008.12

Oral presentation (invited, special)

システムの安全性や信頼性に対する期待の高まりに伴い，システムの動的モデルに基づく高性能ロバスト制御と故障検出・耐故障制御に関する研究が注目を集めている．この問題に対するアプローチの1つとして制御対象の内部モデルに基づくGIMC(Generalized Internal Model Control)構造による制御系設計法が提案されている．本講演ではまず，GIMC構造の基本的な考え方と高性能ロバスト制御について説明し，その後内部モデルから得られる推定誤差信号によるオンライン故障検出と補償器の切替に基づく耐故障制御系の構築に関して述べる．最後に幾つかの応用例を紹介する．

Consensus Filter Based Target-enclosing Strategies for Multiple Nonholonomic Vehicles

H. Kawakami and T. Namerikawa

Proc. of the 47th IEEE Conference on Decision and Control (Cancun,Mexico) ,

2008.12

Oral presentation (general)

A State Predictor for Bilateral Teleoperation with Communication Time Delay

K. Yoshida, T. Namerikawa and O. Sawodny

Proc. of the 47th IEEE Conference on Decision and Control (Cancun,Mexico) ,

2008.12

Oral presentation (general)

本稿では予測制御手法の性能を改善するために, システムの解軌道に基づく予測器を提案した. 提案予測器は過去の予測偏差が現在の予測偏差に影響を与えない. 提案予測器をPD 制御則に導入し, 適応インピーダンス制御による線形化と組み合わせた. また提案する制御手法を適用した際の安定性をリアプノフ法により示した．さらにシミュレーションにより提案予測器と従来の予測器の性能比較を行い，実験により提案制御手法の位置追従性能や反力の伝達特性を検証した.

マルチエージェントシステムとフォーメーション制御～合意問題とビークルフォーメーション制御への応用～（招待講演）

NAMERIKAWA Toru

第5１回自動制御連合講演会　第７回特別チュートリアル講演会－未来に向かう学生，若手研究者・技術者のSICEへのいざない－ (Yonezawa,Japan) ,

2008.11

Oral presentation (invited, special)

Virtual Structure Based Target-enclosing Strategies for Nonholonomic Agents

H. Kawakami and T. Namerikawa

Proc. of IEEE Multi-conference on Systems and Control (San Antonio,USA) ,

2008.09

Oral presentation (general)

本稿では仮想構造を用いて，仮想エージェントが仮想対象物を取り囲むことにより，実対象物を取り囲む制御則をマルチエージェントシステムとリーダ・フォロアシステムの場合に対して提案し，それぞれに対して取り囲みを漸近的に達成することを示した．最後に提案制御則の有効性をシミュレーションと制御実験にて検証し，その結果，提案制御則において取り囲みを達成することができた．

Observer-based Consensus Control Strategy for Multi-Agent System with Communication Time Delay

C. Yoshioka and T. Namerikawa

Proc. of IEEE Multi-conference on Systems and Control (San Antonio,USA) ,

2008.09

Oral presentation (general)

本稿では，通信遅延を有する場合のマルチビークルシステムの安定化と情報削減のためのオブザーバベース出力合意問題について考える．具体的には合意ゲインの設計法，通信遅延を有する場合の安定性条件，オブザーバを併合した場合の安定性条件を導く．更に提案したマルチビークルシステム制御手法を実システムに応用し制御実験により有効性を検証する．

Consensus Control of Observer-based Multi-Agent System with Communication Delay

T. Namerikawa and C. Yoshioka

Proc. of the SICE Annual Conference 2008 (Chofu,Japan) ,

2008.08

Oral presentation (general)

本稿では，通信遅延を有する場合と情報軽減のために位置情報のみを情報交換するFlocking問題について議論した．通信遅延を有する場合でもシステムが安定となるための条件を導出し，また，情報量軽減のためにオブザーバベースマルチビークルシステムを提案した．また，通信遅延を考慮したオブザーバベースマルチビークルシステムの有効性を制御実験により示した．

Predictive PD Control for Teleoperation with Communication Time Delay

K. Yoshida and T. Namerikawa

Proc. of the 17th IFAC World Congress (Seoul,Korea) ,

2008.07

Oral presentation (general)

本稿では通信遅延を有するロボットアームのテレオペレーションに対して遅延の影響を減少させるための予測型PD 制御則を提案した. 提案手法では環境のモデルが制御則に不必要で, 多自由度ロボットアームへ適用可能, モデルパラメータの不確かさの影響を受けないという利点がある. リアプノフ法により提案するテレオペレーションの応答とtarget impedance の応答との偏差の一様終局有界性を示した. さらに実験により提案法の有効性を確認した.

GIMC-based Fault Detection and Its Application to Magnetic Suspension System

Y. Nakaso and T. Namerikawa

Proc. of the 17th IFAC World Congress (Seoul,Korea) ,

2008.07

Oral presentation (general)

本稿では, 故障検出フィルタに関する2 つの最適化問題を定式化し, それぞれに対する最適故障検出フィルタを導出した. また磁気浮上系に対し, 外乱および故障信号を含めたモデルを導出し, 2 つの故障検出フィルタの設計をおこなった. さらに正常稼動時および故障発生時におけるコントローラの設計をおこない, GIMC 構造を構築することで, 耐故障制御系を構築した. 構築した制御系に対し, センサ故障を想定した検証実験を行い，提案法の有効性を示した.

Formation Control of Nonholonomic Multi-vehicle Systems Based on Virtual Structure

C. Yoshioka and T. Namerikawa

Proc. of the 17th IFAC World Congress (Seoul,Korea) ,

2008.07

Oral presentation (general)

本論文は仮想構造(VS)を用いたマルチビークルシステムのフォーメーション制御手法を提案する．非ホロノミック系においてVSを用いることにより，任意のフォーメーション形成が可能とする．また，Flocking 問題に対しても同様な制御則を提案し，その漸近安定性を示す．最後に，提案した制御則について，マルチビークルシステムのフォーメーションと制御実験を行い，その有効性を示す．

Bilateral Control of Nonlinear Teleoperation with Time Varying Communication Delays

H. Kawada and T. Namerikawa

Proc of the 2008 American Control Conference (Seattle,USA) ,

2008.06

Oral presentation (general)

本稿では時変の通信遅延を有する非線形テレオペレーションに対して新しい制御則を提案する．提案制御則は通信遅延の変化率に依存した時変な速度制御器と最大遅延に制約される位置制御器で構成される単純なPD 型制御である．Lyapunov Krasovskii 関数を用い，時変の通信遅延を有するテレオペレーションが漸近安定となることを示す．さらにマスタとスレーブの位置協調，スレーブの静的な接触力が操縦者に伝達されることを示す．最後に制御実験により提案法の有効性を示す．

マルチエージェント問題への制御理論的アプローチ（招待講演）

NAMERIKAWA Toru

電子情報通信学会　ニューロコンピューティング研究会（NC） (Kanazawa,Japan) ,

2008.05

Oral presentation (invited, special)

本講演では, 複数のエージェントに対し, 合意アルゴリズムを基に, より広いネットワークグラフ構造に対する合意制御則について解説した. 本手法はグラフの平衡性を必要とせず，先行研究に比べてより広いクラスに適用可能であり，容易な制御器の設計法をLyapunov の安定定理を用いて導出している．また状態推定を含む出力合意問題に対して, エージェントの数に依存しない状態推定方法を用いた合意制御則を提案した．最後に制御実験結果を紹介した．

マルチビークルシステムの合意問題とフォーメーション制御（招待講演）

NAMERIKAWA Toru

計測自動制御学会北陸支部　チュートリアル講演会「フォーメーション制御の理論と応用 in Kanazawa」講師 (神奈川県) ,

2007.12

Other

Synchronized Control for Teleoperation with Different Configurations and Communication Delay

H. Kawada, K. Yoshida and T. Namerikawa

Proc. of the 46th IEEE Conference on Decision and Control (New Orleans,USA) ,

2007.12

Oral presentation (general)

本稿は通信遅延を有する異構造テレオペレーションに対して漸近安定性を保証した受動性に基づく同調制御手法を提案する. 本稿では同調制御則のマスタおよびスレーブのゲインを, 異構造を考慮して独立に設計できるコントローラを提案する. これにより追従誤差を少なくし，位置と力のスケーリングの大きさを独立に設定できる. リアプノフの安定法を用いることで, 提案するテレオペレーションが漸近安定となることを示す. 更に制御実験により, 提案手法の有効性を示す.

Formation Control of Nonholonomic Multi-Vehicle Systems via Virtual Structure

T. Namerikawa and C. Yoshioka

Proc. of the Fourth International Conference on Computational Intelligence Robotics and Autonomous Systems (Palmerston North,New Zealand) ,

2007.11

Oral presentation (general)

本稿では，仮想構造を用いたマルチビークルシステムのフォーメーション制御手法を提案した．非ホロノミック系において仮想構造を用いることにより，任意のフォーメーション形成が可能となった．また，Flocking 問題に対しても同様な制御則を提案し，その漸近安定性を示した．最後に，提案した制御則について，ビークル5 台でのフォーメーションと制御実験を行い，その有効性を示した．

Robust Stabilization of Running Self-Sustaining Two-wheeled Vehicle

H. Sato and T. Namerikawa

Proc. of the 2007 IEEE Conference on Control Applications (Singapore) ,

2007.10

Oral presentation (general)

本研究では，この自立走行二輪車に対して走行安定化を目的とした制御系を構成する．制御器の設計にはH∞ 混合感度問題を用いて，二輪車の質量が変動した場合においても安定した走行を実現させる．走行実験により走行中に受ける外乱に対しても安定化可能であることを示す．また，二輪車の質量変動に対しても安定に走行できることを確認し，設計した制御器の有効性を示す．

GIMC Structure Considering Communication Delay and Its Application to Mechatronic System

T. Namerikawa and J. Miyakawa

Proc. of the 2007 American Control Conference (New York) ,

2007.07

Oral presentation (general)

本稿ではスミス法を用いたGIMC 構造の提案を行い，その構造がむだ時間を含む系でも高性能かつ高ロバストな制御を行えることを実験的に示した. 実際にスミス法を用いたGIMC 構造を磁気浮上システムに応用し, むだ時間誤差がない場合には高性能制御を行い，安定性を損なうような大きな誤差を生じた場合はコントローラの切り替えにより安定性を保持できることを示した. またコントローラと制御対象をネットワーク結合したシステムに対しても本手法が有効であることを示した.

Symmetric Impedance Matched Teleoperation with Position Tracking

T. Namerikawa and H. Kawada

Proc. of the 45th IEEE Conference on Decision and Control (San Diego,USA) ,

2006.12

Oral presentation (general)

本研究では従来法に対して，仮想的な粘性摩擦を持つ対称型テレオペレーションを提案する．これにより，従来法の問題点を解決し良好な位置追従性を実現できる．提案するテレオペレーションに対して，リアプノフの方法に基づく設計法を用いることでシステムが安定となる位置制御ゲインの条件を導く．最後に，制御実験を行うことで提案法の有効性を示す．

Passivity-based Synchronized Control of Teleoperation with Power Scaling

H. Kawada and T. Namerikawa

Proc. of the SICE-ICCAS International Joint Conference 2006 (Busan,Korea) ,

2006.10

Oral presentation (general)

本研究では，通信遅延を有する位置追従性を考慮したテレオペレーションに対して，漸近安定性を保証した受動性に基づくパワースケーリング制御手法を提案した. 提案するパワースケーリング制御手法は，同調制御則に対して任意のスケーリング要素を導入したものである. リアプノフの安定法を用いることで, パワースケーリングを考慮したテレオペレーションが漸近安定となることを示した. また，制御実験により提案法の有効性を示した.

GIMC-based Switching Control of Magnetically Suspended Steel Plates

H. Maruyama and T. Namerikawa

Proc. of the 2006 IEEE Conference on Control Applications (Munich,Germany) ,

2006.10

Oral presentation (general)

本稿ではGIMC構造が内部信号によって高性能コントローラと高ロバストコントローラを切り替え，高性能とロバスト性を両立できることを実験により確認した．また磁気浮上システムを用いた制御実験ではμ- 設計との比較によって有効性が示された．また制御対象の変動に対する安定性と制御性能に関しては，GIMC構造は変動を検出した時点で内部信号に応じて適切なコントローラに切り替えが行われ，対象の状況に応じた補償器へ適応していることを確認した．

Experimental Evaluation on H∞DIA Control of Magnetic Bearings with Rotor Unbalance

H. Seto and T. Namerikawa

Proc. of the 10th International Symposium on Magnetic Bearings (Martigny,Switzerland) ,

2006.08

Oral presentation (general)

本論文では，磁気軸受のロータ回転時に発生する不釣合い振動を，回転速度に同期した周波数を持つ周期的外乱とみなし，その周期的外乱を考慮することによってH∞ DIA 制御に良好な回転性能を持たせる．これによりシンプルなフィードバック構造で磁気軸受の不釣合い振動を考慮することができる．また提案手法によるH∞ DIA 制御を用いて切替え制御則を構成することによって，複数の回転速度で不釣合い振動を抑制することを実験的に検証する．

An H∞ Control Considering Initial State Uncertainties of Controllers

T. Namerikawa and K. Maruyama

Proc. of the 17th International Symposium on Mathematical Theory of Networks and Systems (Kyoto,Japan) ,

2006.07

Oral presentation (general)

本論文では外乱とコントローラの初期状態の不確かさの混合減衰H∞ 制御問題について考察した．まず外乱と制御器の初期状態の不確かさの影響の混合減衰H∞ 制御問題を定式化し，可解条件の必要十分条件を導出した．また磁気浮上システムを例として制御系設計を行い，シミュレーションによる検証により，提案法の初期値応答，過渡応答に対する有効性を確認した．

A Passivity-based Approach to Wide Area Stabilization of Magnetic Suspension Systems

T. Namerikawa and H. Kawano

Proc. of the 2006 American Control Conference (Minneapolis,USA) ,

2006.06

Oral presentation (general)

本研究では磁気浮上システムに対して漏れインダクタンスを考慮したモデルを考え，モデルを電気系サブシステムと機械系サブシステムに分割し, その受動性を示した．またそれぞれのサブシステムに対してのコントローラを設計した．制御実験ではステップ応答, さらに浮上体の質量を変更したときの応答を観測し，提案法では従来法に比べ過渡応答時の振動を抑えることができた．

High Performance Robust Control of Magnetic Suspension Systems Using GIMC Structure

T. Namerikawa and H. Maruyama

Proc. of the 2006 American Control Conference (Minneapolis,USA) ,

2006.06

Oral presentation (general)

Robust Control of Master-Slave Robot System Considering Environmental Uncertainties

T. Namerikawa, S. Ito and H. Kawada

Proc. of SPIE on Optomechatronic Systems Control (Sapporo,Japan) ,

2005.12

Oral presentation (general)

本研究では，2 自由度マスタ・スレーブシステムのダイナミクスをインピーダンス整形を用いて見かけ上，非干渉・線形化した．線形化されたマスタ・スレーブシステムと環境およびオペレータをまとめて一般化プラントを構成した．導出した一般化プラントに対してμ− シンセシスを用いてオペレータ特性と環境の不確かさおよび遅れ時間を考慮したロバスト制御系を構成した．求めたコントローラを用いて制御実験を行い，提案法の有効性を確認した．

H∞ DIA Control of Magnetic Bearing Considering Rotor Unbalance

H. Seto and T. Namerikawa

Proc. of the 5th Int. Symp. on Linear Drives for Industry Applications (Awaji-sima,Japan) ,

2005.09

Oral presentation (general)

本稿では磁気軸受のロータ回転時に発生する不釣合い振動を，回転速度に同期した周波数を持つ周期的外乱とみなし，その周期的外乱を抑制するために，H∞ DIA制御問題における一般化プラントに周波数重み関数を導入することで，任意の回転速度における周波数でコントローラ上にピークゲインを付加した．2つのコントローラを切替えることで良好な不釣合い振動の減衰効果と切替え時の過渡応答特性を有することを実験的に確認した．

Robust H∞ DIA Control of Levitated Steel Plates

T. Namerikawa and D. Mizutani

Proc. of the 5th Int. Symp. on Linear Drives for Industry Applications (Awaji-shima,Japan) ,

2005.09

Oral presentation (general)

本稿ではH∞DIA 制御を鋼板磁気浮上システムに適用し，良好な振動抑制特性とモデル変動に対するロバスト性を持つことを検証した．具体的には，提案法を鋼板磁気浮上システムに適用して制御系設計を行い，２つの浮上鋼板を用いて制御実験を行った．PID 制御との比較により，H∞DIA 制御はPID制御より過渡応答時のオーバーシュートの面で劣るが，鋼板の振動抑制に優れる事，モデル変動に対するロバスト性が高い事を確認した．

An H∞ DIA Control System Design of a Magnetic Bearing Considering Periodic Disturbance

H. Seto and T. Namerikawa

Proc. of the 2005 IEEE Conference on Control Applications (Torouto,Canada) ,

2005.08

Oral presentation (general)

Modeling and Robust Attitude Control of Stationary Self-sustaining Two-wheeled Vehicle

H. Sato and T. Namerikawa

Proc. of the SICE Annual Conference 2005 (Okayama,Japan) ,

2005.08

Oral presentation (general)

本研究では静止状態でも二輪車を安定化可能とするため，ライダの重心移動に相当する台車系とハンドル操作系を備えた自立走行二輪車を構成した．Lagrange 法により運動方程式を導出し，更に静止状態に限定した線形モデルを定義した．このモデルに対する安定化制御器をH∞ループ整形設計手法を用いて設計し，姿勢制御実験を行った．実験の結果，最適レギュレータで設計したコントローラと比べ，インパルス外乱応答において良好な結果が得られた．

Robust Control of Master-Slave Robot System Considering Environmental Uncertainties

R. Lin and T. Namerikawa

Proc. of IEEE Int. Conf. on Advanced Intelligent Mechatronics (Monterey) ,

2005.07

Oral presentation (general)

本研究では2台の2自由度マニピュレータを用いたマスタ・スレーブシステムを構築し，環境，モデルの不確かさと通信遅延を考慮したロバスト制御系をインピーダンス整形とμ-シンセシスにより構成した．ここでインピーダンス整形により非線形特性を有する多自由度ロボットの非干渉化と線形化を行い，構造的な不確かさ表現を用いることで，多様な不確かさの要素を統一的に見通しよく扱うことが可能となった．最後に提案法の有効性を制御実験により検証した．

Improving the Rotational and Transient Performance of Magnetic Bearings by the H∞ DIA Control

T. Namerikawa and H. Seto

Proc. of the 2005 American Control Conference (Portland,USA) ,

2005.06

Oral presentation (general)

本稿では無限時間区間における外乱と初期状態の不確かさの混合減衰H∞ DIA制御問題を直交条件を課さない場合について定式化し，その問題に対する解の存在性に関して3つのLMIを用いた必要十分条件を与えている．さらに導出したLMI条件に基づいて磁気軸受に対してコントローラを設計する．制御実験では，回転運動中の磁気軸受ロータに対する振動減衰特性を従来法と比較することにより，H∞ DIA制御の有効性を確認する．

H∞ DIA Control of Magnetic Suspension Systems

T. Namerikawa and M. Fujita

Proc. of the 2004 IEEE Conference on Control Applications (Taipei,Taiwam) ,

2004.09

Oral presentation (general)

本論文では無限時間区間における外乱と初期状態の不確かさの混合減衰H∞ DIA制御問題を直交条件を課さない場合について定式化し，その問題に対して1つの解を与えている．この結果を用いて磁気浮上システムに対して制御系設計を行い，制御実験により，理論検証を行なった．特に状態量のレギュレーションに関わるパラメータとH∞ DIA制御での重みN，また過渡応答特性との関係を明らかにした．これによりH∞ DIA制御の有用性を確認した．

Robust Performance and Transient Response of the H∞/μ DIA Control for Magnetic Suspension Systems

H. Seto and T. Namerikawa

Proc. of the 2004 IEEE Conference on Control Applications (Taipei,Taiwan) ,

2004.09

Oral presentation (general)

本研究では，H∞ DIA 制御問題にμ-シンセシスを組み合わせた制御問題を設定することによって良好な過渡応答特性とロバスト制御性能の両方をもつ補償器を実現することができた．具体的には，この提案法を磁気浮上システムに対して適用して過渡応答特性とロバスト制御性能の両方を有する制御系の設計を行い，制御実験により提案理論の検証を行い，その有効性を実験的に示した．

Improving the Transient Response of Magnetic Bearings by the H∞ DIA Control

W. Shinozuka and T. Namerikawa

Proc. of the 2004 IEEE Conference on Control Applications (Taipei,Taiwan) ,

2004.09

Oral presentation (general)

本稿では外乱と初期状態の不確かさの混合減衰H∞ DIA 制御問題を磁気軸受に適用し，多入出力系における提案法の有効性を検証した．具体的には最適制御に基づく状態フィードバックとH∞ DIA 制御の制御実験の応答を比較し，ノミナルなステップ応答を除く外乱除去性能，ロバスト性能，初期値応答特性に提案法が優れていることを制御実験により確認した．

H∞ DIA Control For Robust Performance of Magnetic Suspension Systems

T. Namerikawa and H. Seto

Proc. of the 7th Int. Conference on Motion and Vibration Control (St.Louis,USA) ,

2004.08

Oral presentation (general)

本稿ではH∞DIA制御のアプローチを用いて，磁気浮上システムに対して制御系設計を行い，H∞DIA制御の特性を実験的に検証した．具体的には，初期状態の不確かさに対する重み行列Nと設計されたロバスト補償器の周波数特性を解析し，それらが制御実験に与える影響について検証と考察を行なった．これにより，外乱と初期状態の不確かさの混合減衰H∞DIA制御の有用性を確認した．

Disturbance and Initial State Uncertainty Attenuation Control for Magnetic Bearings

T. Namerikawa, W. Shinozuka and M. Fujita

Proc. of the 9th Int. Symposium on Magnetic Bearings (Kentucky,USA) ,

2004.08

Oral presentation (general)

本研究ではH∞DIA 制御を磁気軸受に応用し，ロバスト性と過渡応答特性を考慮した磁気軸受制御系を構成する．まず，ロータダイナミクスや電磁石の非線形特性などを考慮した磁気軸受の数学モデルを作成し，次に磁気軸受に対してH∞DIA制御系設計を行う．最後に制御実験によりH∞DIA 制御の過渡応答性能，初期状態の不確かさに対する性能，また外乱応答やモデル変動に対する応答などについて評価検討を行う．

H∞/μ DIA Control of the Magnetic Suspension System

T. Namerikawa and H. Seto

Proc. of the 8th Int. Workshop on Advanced Motion Control (Kawasaki,Japan) ,

2004.03

Oral presentation (general)

本研究では，μ-シンセシスにH∞DIA 制御を適用し，上記の２つの特徴を有する制御系の設計を磁気浮上システムに対して行う．これにより，双方の特徴である良好な過渡応答特性とロバスト制御性能の両方を有する補償器の実現が期待できる．本稿では提案手法を磁気浮上システムに応用し実際に制御実験によって過渡応答特性とロバスト制御性能の検証を行い，提案法の有効性を示す．

H∞ Control of the Magnetic Bearing Considering Initial State Uncertainties

T. Namerikawa and W. Shinozuka

Proc. of the 8th Int. Workshop on Advanced Motion Control (Mito,Japan) ,

2004.03

Oral presentation (general)

本研究ではH∞DIA制御を磁気軸受に応用し，ロバスト性と過渡応答特性を考慮した磁気軸受制御系を構成する．まずロータダイナミクスや電磁石の非線形特性などを考慮した磁気軸受の数学モデルを作成し，次にH∞DIAを用いて，磁気軸受に対して制御系設計を行う．最後に従来法としてPID制御および状態フィードバック制御によるコントローラとH∞DIA制御のコントローラの応答をシミュレーションと制御実験により比較することで，提案法の有効性検証を行なう．

H∞ Control Attenuating Initial State Uncertainties and its application to Magnetic Suspension Systems

T. Namerikawa

The 7th Joint Seminar between TU and NUT and Collaborative Workshop for Thai Students at NUT (Bangkok,Thailand) ,

2003.12

Oral presentation (general)

本論文では無限時間区間における外乱と初期状態の不確かさの混合減衰H∞ DIA制御問題について定式化し，その問題に対して1つの解を与えている．この結果を用いて磁気浮上システムに対して制御系設計を行い，制御実験により，理論検証を行なった．特に状態量のレギュレーションに関わるパラメータとH∞ DIA制御での重みN，また過渡応答特性との関係を明らかにした．これによりH∞ DIA制御の有用性を確認した．

H∞ Control Attenuating Initial State Uncertainties and its Application to the Magnetic Suspension System

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

Proc. of the 8th Int. Symp. on Magnetic Bearings (Mito,Japan) ,

2002.08

Oral presentation (general)

本稿では「一般化された初期状態の不確かさを考慮したH∞制御理論」を磁気浮上システムに応用し，制御系設計，数値シミュレーションを行うことで提案法の過渡応答性能に対する有効性を明らかにした．ここで提案法では，従来法に比べて制御系設計における自由度が増えたため，設計パラメータの選択が容易になり，制御入力のレギュレーションと外乱の特徴付けが可能となった．結果として良好な制御系を設計することが可能となった．

A Generalized H∞ Control System Design Attenuating Initial State Uncertainties

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

Proc. of the 2002 American Control Conference (Anchorage,USA) ,

2002.05

Oral presentation (general)

本稿では，従来の「初期状態の不確かさを考慮したH∞制御」の枠組みから，制御対象に対する直交条件を排除し，より一般化した制御対象に対して初期状態の不確かさと外乱の混合減衰H∞制御問題を設定した．この問題に対して，解の存在のための必要十分条件と解の１つの構成法を与えた．これにより従来に比べて広範な制御対象を取り扱うことが可能となり，制御系設計における制約が少なくなり，設計における自由度を増加させた．

H∞ Control System Design Attenuating Initial State Uncertainties: Evaluation by a Magnetic Suspension System

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

Proc. of the 40th IEEE Conference on Decision and Control (Orland,USA) ,

2001.12

Oral presentation (general)

本稿では磁気浮上システムに制御対象の初期状態の不確かさを考慮したH∞制御を応用し，従来のH∞制御と比較検討することにより，提案制御法の過渡応答特性に対する有効性を示した．また初期状態の不確かさに対する重みNと過渡応答性能の関係を明らかにした．さらにコントローラのフリーパラメータの自由度を有効に利用することで積分特性など，コントローラに良好な特性を付加できることを実験的に示した．

Robust Performance Analysis of　Magnetic Bearings

T. Namerikawa and M. Fujita

Proc. of 3rd Asian Control Conf. (Shanghai) ,

2000.07

Oral presentation (general)

本稿では磁気軸受の不確かなモデル構造とロバスト制御性能解析に関して議論した．本稿では線形分数変換を用いた保守性の低い不確かさの記述を提案し，ロバスト制御性能解析を閉ループ系の構造化特異値を用いて行った．具体的には提案する構造的な不確かさ表現を用いた場合と，従来の非構造的な不確かさ表現を用いた場合を比較し，提案法を用いることで実際の数値実験に近いロバスト性能解析結果が得られることを示した．

Robust Performance Analysis of Uncertain Magnetic Bearings

T. Namerikawa and M. Fujita

Proc. of 2000 ASME Int. Gas Turbine and Aeroengine Congress and Exhibition (Munchen,Germany) ,

2000.05

Oral presentation (general)

本稿は磁気軸受の不確かなモデル構造とロバスト制御性能に関して議論する．特に磁気軸受制御で問題となる，電磁石吸引力の非線形性，電磁石部の複雑なダイナミクス，パラメータ誤差，ジャイロ効果を構造的な不確かさとして表現し，これらを統一的にロバスト制御の枠組みで扱えることを示した．得られたモデルに対してロバスト制御性能を達成する補償器設計を行い，数値実験によりモデル変動と性能の関係について検討をおこなった．

Uncertain Model and μ- Synthesis of a Magnetic Bearing

T. Namerikawa and M. Fujita

Proc. of 1999 IEEE Int. Conf. on Control Applications (Hawaii,USA) ,

1999.08

Oral presentation (general)

Uncertainty Structure and μ- Design of a Magnetic Suspension System

T. Namerikawa, M. Fujita and F. Matsumura

Proc. of 6th Int. Symp. on Magnetic Bearings (Boston,USA) ,

1998.08

Oral presentation (general)

本論文は磁気浮上システムの不確かさの記述とμ-設計に関して議論する．まず磁気浮上システムに対して，公称モデル，また不確かさの構造，そして動作点の移動に伴う不確かさの定量化を行なう．つぎに得られたモデルに対してコントローラを混合（実数・複素数）μ-解析法に基づいて設計した．これにより，従来に比べロバスト性解析の際の評価の保守性を軽減した．最後に提案モデル，設計手法，そしてロバスト性解析を実験的に検証した．

Wide Area Stabilization of a Magnetic Bearing Using Exact Linearization

T. Namerikawa, M. Fujita and F. Matsumura

Proc. of 6th Int. Symp. on Magnetic Bearings (Boston,USA) ,

1998.08

Oral presentation (general)

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扱う．まず磁気軸受のダイナミクスを非線形微分方程式で記述し，つぎにこのモデルに対して厳密線形化手法を用いて非線形情報を保存した見かけ上の線形モデルを導出した．さらに線形化モデルに対して最適制御により状態フィードバックコントローラを設計し，最後に実験により，浮上位置移動，ロータの回転速度変化など広域な動作点変動に対する性能と安定性の向上を確認した．

Modeling and Robustness Analysis of a Magnetic Suspension System Considering Structured Uncertainties

T. Namerikawa and M. Fujita

Proc. of 36th IEEE Conf. on Decision and Control (San Diego,USA) ,

1997.12

Oral presentation (general)

本論文は磁気浮上システムのモデリングと不確かさの記述，そしてロバスト安定性解析，ロバスト制御性能解析に関して議論した．まずシステムの公称モデルを導出し，つぎに動作点の変動範囲を考慮することにより不確かさを定量的に見積もった．更に定量化された不確かさを構造的な不確かさとして含む内部結合構造を導出し，これに対して補償器を設計した．最後に実験に基づく制御系のロバスト安定性／ロバスト性能の解析を行った．

μ-Analysis and Synthesis of a Magnetic Suspension System Considering Structured Uncertainties

T. Namerikawa, M. Fujita and F. Matsumura

Proc. of 4th NASA Int. Symp. on Magnetic Suspension Technology (Gifu,Japan) ,

1997.11

Oral presentation (general)

本論文は磁気浮上システムの構造的な不確かさを考慮してμ-設計によりロバスト性能を有するコントローラを設計する．まずシステムの公称モデルと不確かさを導出するが，ここで不確かさとして線形化誤差，パラメ－タの不確かさ，無視されたダイナミクスを扱う．つぎに不確かさと公称モデルを含む内部結合構造を導出し，さらに得られた内部結合構造に対してロバスト補償器を設計し，最後に実験により提案法の有効性を検証した．

Modeling and Robust Control of Self-Sensing Magnetic Bearings with Unbalance Compensation

A.M. Mohamed, F. Matsumura, ＜U>T. Namerikawa＜/U> and J. H. Lee

Proc. of 1997 IEEE Int. Conf.　on Control Applications (Hartford,USA) ,

1997.10

Oral presentation (general)

本稿は磁気軸受の新しいモデリング方法と，位置センサを用いずにロータの安定化を行うセルフセンシング制御法を提案した．このモデルでは浮上ロータを非接触支持する４つの軸を独立に制御することが可能となり，制御系設計の際に多入出力系である磁気軸受を非干渉化し，制御系設計が容易になる利点を有する．さらにモデルに基づき状態オブザーバを構成し，電流センサのみで位置センサを使用しない磁気軸受制御系を構成した．

Q-Parameterization / μ Control of an Electromagnetic Suspension System

A.M. Mohamed, F. Matsumura, T. Namerikawa and J. H. Lee

Proc. of 1997 IEEE Int. Conf.　on Control Applications (Hartford,USA) ,

1997.10

Oral presentation (general)

本稿では磁気浮上システムの安定化問題に対して，Q-パラメトリゼーションとμ-設計法を組み合わせることで，複数の制御仕様を満たす補償器設計を行い，高機能な制御系を実現した．具体的には，１．コントローラの極の領域指定，２．加法的不確かさに対するロバスト安定条件，３．外乱除去問題に対するロバスト性能条件，という問題設定に対して制御系設計を行った．得られたμコントローラを用いて制御系実験を行い，提案法の有効性を検証した．

Robust H∞ Control of a Flexible-Joint Robot Manipulator using a Linear Parameter Varying Representation

T. Namerikawa, M. Fujita and F. Matsumura

Proc. of 2nd Asian Control Conf. (Seoul,Korea) ,

1997.07

Oral presentation (general)

本稿では柔軟関節を有するロボットマニピュレータに対して，駆動モータのみの関節角度情報を基にしたロバスト制御問題を扱う．まず柔軟関節を有するロボットマニピュレータのダイナミクスをLPVシステムとして表現し，つぎにLPVシステムに対してH∞制御を適用してロバスト制御系を構成した．最後にマニピュレータの位置制御問題に対して，関節の柔軟性とリンク位置変動が存在する場合にも本手法が有効であることを数値シミュレーションにより検証した．

Robust Force Control of a Pantograph System by considering Model Parameter Perturbation

T. Namerikawa, S. Goto and F. Matsumura

Proc. of 1997 IEEE / ASME Int. Conf. on Advanced Intelligent Mechatronics (Tokyo,Japan) ,

1997.06

Oral presentation (general)

本稿ではリニア直流モータをアクチュエータとして有するパンタグラフ基礎実験装置において, 種々の力外乱に対しても架線-パンタグラフ間の接触圧を一定にするレギュレータ問題を扱う．モータ推力定数などのモデルパラメータの物理的変動, 無視したダイナミクスなどの不確かさを実験的に測定, 定量化し，その不確かさに対してμ-設計の枠組でロバスト制御器を設計し，ステップ状外乱に対する時間応答，また周期外乱に対する外乱除去周波数特性を向上させた．

H∞ Control of a Robot Manipulator Using a Linear Parameter Varying Representation

T. Namerikawa, M. Fujita and F. Matsumura

Proc. of 1997 American Control Conf. (Albuquerque,USA) ,

1997.06

Oral presentation (general)

本稿では線形パラメータ変動(LPV)表現に基づいたH∞制御によるロボットマニピュレータのロバスト軌道追従問題を扱う．まずロボットマニピュレータのダイナミクスを関節角度をスケジューリングパラメータとするLPVシステムとして表現し，つぎにLPVシステムに対してH∞コントローラを設計した．ここで制御系設計の際にはパラメータ凍結法を用いて，最悪ケースにおいてもH∞ノルム条件を満たすコントローラを設計した．最後にシミュレーションにより有効性を検証した．

Q-parameterization control of vibrations in a variable speed magnetic bearing

Mohamed Abdelfatah M., Matsumura Fumio, Namerikawa Toru, Lee Jun Ho

Proceedings of the 1997 IEEE International Conference on Control Applications,

1997

A controller design methodology was proposed using Q-parameterization theory for a variable speed magnetic bearing to control the vibrations. A mathematical model in a state space form was used for the bearings. The controller free parameter Q was assumed to be a proper stable transfer function whose order equals twice the number of operating speeds. A set of linear equations was solved to satisfy the design objectives. Several simulations obtained to evaluate the controller showed the effectiveness of the controller in eliminating the vibrations at different speeds.

Improvement of Dynamic Response by Flux Feedback on Active Magnetic Bearings

S. Hara, T. Namerikawa and F. Matsumura

Proc. of 5th Int. Symp. on Magnetic Bearings (未記入) ,

1996.08

Other

Experimental Evaluation of Gain Scheduled H∞ Robust Controllers to a Magnetic Bearing

T. Namerikawa, K. Hagiwara, M. Fujita and F. Matsumura

Proc. of 5th Int. Symp. on Magnetic Bearings (Kanazawa,Japan) ,

1996.08

Oral presentation (general)

本稿では回転速度が変化する磁気軸受を対象とし，この対象に対して回転速度情報を基にコントローラのゲインを適応的に変化させるゲインスケジュールドH∞制御を適用し，有効性を実験的に検証している．まず磁気軸受をロータの回転速度に対する線形パラメータ変動(LPV)システムとして表現し，これにより高速回転時に問題となるジャイロ効果と不釣合い振動を考慮した．つぎに実際にこのLPVシステムに対してロバスト制御系を構成し，最後に提案法の有効性を実験的に検証した．

A Linear Parameter Varying Approach to a Gain Scheduled Flexible Joint Robot

T. Namerikawa, M. Fujita and F. Matsumura

Proc. of 4th Int. Workshop on Advanced Motion Control (Tsu,Japan) ,

1996.03

Oral presentation (general)

本稿では柔軟関節を有するロボットマニピュレータのロバスト位置制御問題を扱う．まず，柔軟関節を有するマニピュレータに対して，リンクの座標系を適切に選ぶことにより線形パラメータ変動(LPV)システム表現が可能であることを証明した．さらに得られたLPVシステムに対して，スケジューリングパラメータの情報に基づきH∞ノルムによる閉ループ系の解析を行った．最後に数値シミュレーションにより，提案法の有効性を検証した．

Robust control of a robot manipulator using a linear parameter varying representation

Namerikawa Toru, Matsumura Fumio, Fujita Masayuki

IEEE International Conference on Industrial Technology, 1996,

1996

In this paper, we present a robust control for a flexible-joint robot manipulator using linear parameter varying representation. The robot manipulator dynamics can be brought to a quasi linear parameter varying (LPV) form by a state transformation. An LPV system is defined as a linear at system whose dynamics depend on an exogenous variable which can be measured upon system operation. In this case, the scheduling variables are the joint angles q. which are state variables. Using a quasi-LPV form, we design a robust controller by μ-synthesis to achieve robust performance specification.

Robust Trajectory Following for an Uncertain Robot Manipulator Using H∞ Synthesis

T. Namerikawa, M. Fujita and F. Matsumura

Proc. of 3rd European Control Conf. (Roma,Italy) ,

1995.09

Oral presentation (general)

本稿ではロボットマニピュレータのロバスト位置制御問題を扱う．具体的にはマニピュレータダイナミクスのリンク間の干渉項や重力項などの非線形項をモデルの時変な摂動として表現し，これをLFT表現することにより，ロボットマニピュレータのロバスト位置制御問題を線形システムに時変な摂動を持つ系の制御問題として定式化した．この問題に対して定数スケーリングH∞制御による制御系設計を行い，従来法に比べ良好な結果を得た．

Digital Implementation of Robust μ-Control for a Robot Manipulator

M. Fujita, T. Namerikawa and K. Uchida

Proc. of 1994 American Control Conf. (Baltimore,USA) ,

1994.06

Oral presentation (general)

本稿はロボットマニピュレータのロバスト位置制御問題に対して，手先負荷の変動と演算時間遅れを考慮したモデル集合を導出し，μ-設計法によりロバスト制御系を構成した結果を述べている．特にディジタル制御装置での実装問題に着目し，高速運動するロボットに対して，演算時間遅れを一種のモデル変動として表現し，そのモデル変動に対するディジタル制御の際の制御性能問題に対して軌道追従制御実験により検討を行った．

Robust Position Control and its Implementation for a Robot Manipulator Using μ-Synthesis

T. Namerikawa, M. Fujita and F. Matsumura

Proc. of 3rd Int. Workshop on Advanced Motion Control (Barkley,USA) ,

1994.03

Oral presentation (general)

本稿ではロボットマニピュレータのロバスト位置制御問題を扱っている．まず手先負荷が変動するロボットマニピュレータのダイナミクスを考慮し，それに対するモデル集合を導出した．この際にディジタル制御の実装のための時間遅れも考慮した．つぎにμ-設計法によりモデル集合に対してロバスト制御系を構成することにより，負荷変動に対してロバストなコントローラを設計した．提案手法の有効性をディジタル制御実験により検証した．

μ- Synthesis of an Electromagnetic Suspension System

M. Fujita, T. Namerikawa, F. Matsumura and K. Uchida

Proc. of 31st IEEE Conf. on　Decision and Control (Tucson,USA) ,

1992.12

Oral presentation (general)

本稿では不安定系である磁気浮上システムに対して，モデリングの際の仮定に応じて4つの線形モデルを導出し，それぞれの線形モデルに対してパラメータ変動を考慮することにより，24個の制御対象のモデルを考慮した．その全てのモデルを１つの公称モデルと非構造的な加法的変動の和としたモデル集合として表現し，このモデル集合に対して，μ-設計法により考慮したすべての変動に対してロバスト性能を有する制御系設計を行った．

μ- Analysis and Synthesis of a Flexible Beam Magnetic Suspension System

M. Fujita, F. Matsumura and T. Namerikawa

Proc. of 3rd Int. Symp. on Magnetic Bearings (Washington,D.C.USA) ,

1992.08

Oral presentation (general)

本稿は高速回転する磁気軸受をモデルとした，柔軟ビーム磁気浮上システムに対して，世界的にも先駆的にμ- Analysis and Synthesis理論を適用した結果である．制御対象の質量や，アクチュエータである電磁石の抵抗値などのパラメータが変化し，システムにモデル変動が生じた場合にもロバスト性能を達成する制御系を構成している．またその効果を制御実験により検証している．

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