研究者詳細 - 瀨部　昇

論文 - 瀨部　昇

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Realization of the inverse-model-based disturbance observer in the Luenberger-type observer form and its generalization 査読有り国際誌

Shikada K., Sebe N.

SICE Journal of Control, Measurement, and System Integration 18 ( 1 ) 2025年02月

記述言語：英語掲載種別：研究論文（学術雑誌）

This paper gives the state-space representation of the inverse-model-based disturbance observer. The inverse-model-based disturbance observer proposed by Ohishi et al. estimates the disturbance with the inverse model of the plant and a low-pass filter and cancels out the effect of the disturbance with the estimated disturbance. Generally, for non-minimum phase plants, the inverse-model-based disturbance observer is constructed with an approximate stable inverse model or adding a parallel filter. Furthermore, the inverse-model-based disturbance observer is commonly discussed with the transfer function, and the relation between the Luenbergar-type observer is not clear. This paper gives the state-space representation of the inverse-model-based disturbance observer in the Luenberger-type observer form. Furthermore, this paper focuses on the characteristics of the systems for estimating the disturbance and shows the conditions for the Luenberger-type observer to be a disturbance observer. The Luenberger-type disturbance observer that satisfies the condition can be used for non-minimum phase systems since it does not use the inverse system model.

DOI： 10.1080/18824889.2025.2463195

DOI： 10.1080/18824889.2025.2463195

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Sequential Overbounding Approximation Method for the scaled H<inf>∞</inf> control problem 査読有り国際誌

Yoshikami K., Sebe N.

2025 Australian and New Zealand Control Conference, ANZCC 2025 93 - 98 2025年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Australia Gold Coast 2025年01月30日 - 2025年01月31日

The H∞ control is a practical approach for designing robust control systems, notable for permitting frequency shaping within control systems. However, the design result tends to be conservative when parameter uncertainties are treated as unstructured, such as additive and multiplicative. The scaled H∞ control problem has been introduced to address parameter uncertainties. An effective numerical solution, the dual iteration method, has been proposed for the scaled H∞ control problem. While the dual iteration method enhances control performance efficiently, it introduces numerical instability due to the reverse application of the elimination lemma. Therefore, a numerically stable and highly efficient method is needed for the scaled H∞ problem. This paper proposes a numerical method for the scaled H∞ control problem based on the overbounding approximations of an inverse of a positive definite matrix and bilinear terms. The proposed method avoids eliminating the controller variables and achieves numerical stability. The effectiveness of the proposed method is illustrated through numerical examples.

DOI： 10.1109/ANZCC65042.2025.10873324

DOI： 10.1109/ANZCC65042.2025.10873324

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Fault Detection in Robust Control by Using Disturbance Observer and Test Signals 査読有り国際誌

Yuyama T., Tsuji I., Shikada K., Sebe N., Suyama K.

2025 Australian and New Zealand Control Conference, ANZCC 2025 111 - 116 2025年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Australia Gold Coast 2025年01月30日 - 2025年01月31日

It is important to design control systems that are robust against failures. Control systems that maintain control performance even in the presence of faults are called fault-tolerant control. Passive fault-tolerant control is one of the fault-tolerant controls without fault detection. However, it is desirable to detect faults for fault maintenance even if a control system is robust against faults. In general, the more robust control systems are, the less faults affect the signals in control systems. Thus, fault detection in robust control systems is difficult. To achieve robust control and easy fault detection, This paper proposes a fault detection method for robust control systems using a disturbance observer and test signals. In the proposed control system, the disturbance observer has the same generating model that generates the test signals. Numerical examples demonstrate the effectiveness of the proposed method.

DOI： 10.1109/ANZCC65042.2025.10872996

DOI： 10.1109/ANZCC65042.2025.10872996

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Observer-Structured PID Controller: Flight Controller Design Examples 査読有り国際誌

Sato M., Sebe N.

International Conference on Electrical, Computer, Communications and Mechatronics Engineering, ICECCME 2024 1 - 6 2024年11月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Maldives Male 2024年11月04日 - 2024年11月06日

This note shows two design examples of PID con-Trollers, whose state variables estimate the selected state vari-Ables of the controlled plant systems, for LTI Parametrically Dependent (LTIPD) systems. The authors have already proposed observer-structured controllers, whose structure is not the same as but is very similar to the well-established Luenberger observer-based controllers, and have also proposed a conversion method from a priori designed unstructured LTI or Linear Parameter-Varying (LPV) controllers to observer-structured LTI/LPV con-Trollers with the plant state estimation ability implemented. How-ever, the successful conversion has been reported only for full-order controllers. In this note, we show two examples, in which a priori designed LTI PID controllers are successfully converted to observer-structured PID controllers, and the designed observer-structured PID controllers well estimate the selected plant state variables in numerical simulations.

DOI： 10.1109/ICECCME62383.2024.10797124

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Similarities and differences between exosystem-model-based disturbance observer and model error compensator 査読有り国際誌

Shikada K., Sebe N.

SICE Journal of Control, Measurement, and System Integration 17 ( 1 ) 339 - 348 2024年09月

記述言語：英語掲載種別：研究論文（学術雑誌）

This paper clarifies the theoretical similarities and differences between the exosystem-model-based disturbance observer and the model error compensator. In 1972, Johnson proposed the exosystem-model-based disturbance observer. This observer is constructed against the augmented system model, which consists of nominal plant and disturbance-generating models. Ohnishi et al. proposed to cancel out the effect of uncertainties with its estimated disturbance. Furthermore, in 2013, Okajima et al. proposed the model error compensator, which compensates for the error between the output of the nominal plant model and the measurement outputs of the actual plant. The theoretical differences among these control structures have yet to be fully understood. Therefore, this paper theoretically investigates the relation and shows the superiority of the exosystem-model-based disturbance observer to the model error compensator in its freedom to assign the behavior of the uncontrollable modes. This superiority enables the exosystem-model-based disturbance observer to suppress output fluctuations against uncertainties effectively. This effect is shown by a numerical example.

DOI： 10.1080/18824889.2024.2391624

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A Design of H∞ Controllers Achieving Type 2 Sensitivity Characteristics in type 1 Servo Systems 査読有り国際誌

Kawakami R., Shikada K., Sebe N., Sato M.

2024 SICE Festival with Annual Conference, SICE FES 2024 973 - 979 2024年08月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Kochi 2024年08月27日 - 2024年08月30日

This paper proposes an H∞ controller design method which realizes a two-degree-of-freedom (2-DOF) control system with lower sensitivity characteristics in the low-frequency range. A control system with a disturbance observer is a 2-DOF control system that can achieve low sensitivity characteristics in the specific low-frequency range. However, the design of a controller with a disturbance observer structure is a non-convex optimization problem if it is considered as an observer gain design problem. In addition, it has not yet been revealed whether a 2-DOF control system with the low sensitivity characteristics of the disturbance observer can be achieved by the H∞ controller design. Therefore, this paper proposes a design method for H∞ controllers that achieves the low-sensitivity characteristics of a type 2 servo system while maintaining the type 1 servo characteristics without specifying the disturbance observer structure. Numerical examples demonstrate the effectiveness of the proposed method.

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Estimation of Scheduling Parameters by Disturbance Observer 査読有り国際誌

Kamewari K., Shikada K., Sebe N., Sato M., Mizumoto I.

2024 SICE Festival with Annual Conference, SICE FES 2024 980 - 985 2024年08月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Kochi 2024年08月27日 - 2024年08月30日

This paper proposes a method for estimating scheduling parameters using a disturbance observer. The input and output values of the scheduling parameters are estimated by a disturbance observer, and the scheduling parameters are estimated by calculating the ratio of these values. The effectiveness of the gain-scheduled control using the estimated values is verified by comparing the gain-scheduled control with actual scheduling parameters and the conventional robust control designed by the scaled H∞ control.

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A Numerical Method for Scaled H∞ Control Problems Based on Approximation of Inverse of Positive Definite Matrix 査読有り国際誌

Yoshikami K., Sebe N.

2024 SICE Festival with Annual Conference, SICE FES 2024 967 - 972 2024年08月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Kochi 2024年08月27日 - 2024年08月30日

H∞ control is one of the effective design methods for robust control systems and is significant in that it allows frequency shaping in the control system, but the design results are conservative when dealing with parameter as multiplicative uncertainties. The scaled H∞ control problem has been proposed as an approach to handle this problem, and an effective numerical solution method is the dual iteration method. While the dual iteration method efficiently improves the control performance, it also leads to numerical instability. Accordingly, a numerical method for the scaled H∞ problem that has numerical stability and high efficiency is needed. This paper proposes a numerical method for the scaled H∞ control problem based on the approximation of inverse matrices. This paper also shows the effectiveness of the proposed method through a numerical example.

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Switching L2 Gain for Evaluating the Fluctuations Around an Output of a Specified Transfer Property 査読有り国際誌

Koichi Suyama, Noboru Sebe

2024 European Control Conference, ECC 2024 3306 - 3311 2024年06月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Sweden Stockholm 2024年06月25日 - 2024年06月28日

In this paper, we introduce the difference structure to pre- and post-switch systems, to propose a new switching L2 gain for evaluating the fluctuations around an output of a specified transfer property after a system switch. Moreover, we apply it to the initial state design of a newly-activated controller designed by model matching to establish its potential practicality as a design index.

DOI： 10.23919/ECC64448.2024.10591052

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Observer-structured controller for linear parametric plant 査読有り

Sato M., Sebe N.

Automatica 163 2024年05月

記述言語：英語掲載種別：研究論文（学術雑誌）

It is well known that Luenberger observers are useful for the estimation of linear plant states; however, several papers have shown that there is no need to use the nominal state-space (s.s.) matrices of linear parametric plant systems for observer-based controllers to realize good control performance. Regarding observer-based controllers, when LTI controllers are considered for LTI plant systems, a method has been proposed to convert a priori designed unstructured LTI controllers to observer-based ones without altering control performance; however, the method has not been extended to the case of parametric plant systems. This note thus addresses the conversion problem of a priori designed unstructured controllers to observer-based ones for linear parametric plant systems. To this end, we first propose observer-structured controllers, which can be defined for linear parametric plant systems even if their nominal s.s. matrices are unspecified, as a structural extension of Luenberger observer-based controllers, and then show the parametrization of the s.s. matrices of the observer-structured controllers. Using the parametrization, a conversion method, which produces observer-structured controllers derived from the unstructured ones with minimal state estimation errors embedded, is proposed using state-transformation matrices obtained via parametrically dependent LMIs. A practical example (lateral-directional motion control around wing level flight of an airplane using a gain-scheduled controller) is included to demonstrate the usefulness and practicality of our propositions.

DOI： 10.1016/j.automatica.2024.111569

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State space analysis of the relation between two types of disturbance observers 査読有り国際誌

Shikada K., Sebe N.

Proceedings of 2024 SICE International Symposium on Control Systems, SICE ISCS 2024 2A1-1, 8 pages 2024年03月

Dissipativity-constrained learning of MPC with guaranteeing closed-loop stability 査読有り国際誌

Hara K., Inoue M., Sebe N.

Automatica ( The International Federation of Automatic Control ) 157 2023年11月

記述言語：英語掲載種別：研究論文（学術雑誌）

This paper addresses the data-driven approximation of model predictive control (MPC) designed for nonlinear plant systems. MPC has high ability of handling complex system-specifications and of improving the control performance, while it requires high computational complexity. Aiming at reducing the complexity, this paper addresses the data-driven approximation of MPC. To this end, the control law in MPC is described by the Koopman operator, which is a linear operator defined on the infinite-dimensional lifted state space. Then, the problem of data-driven finite-dimensional approximation of the operator is addressed. The problem is formulated as an optimization problem subject to a specified dissipativity constraint, which guarantees closed-loop stability and is modeled by a set of matrix inequalities. This paper also presents a computationally efficient algorithm of solving the optimization problem. Finally, a numerical simulation of controller construction is performed. The approximated MPC control law shows the stability of the overall control system while demonstrating high control performance.

DOI： 10.1016/j.automatica.2023.111271

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A Variant of Extended LMI: Performance Analysis with Static Multiplier for Discrete-Time Lifted Systems 査読有り国際誌

Sato M., Sebe N.

IFAC-PapersOnLine 56 ( 2 ) 5825 - 5830 2023年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

This note revisits extended Linear Matrix Inequality (LMI) formulation of performance analysis, which incorporates static multiplier, for parametrically multi-affine discrete-time Linear Time-Invariant Parameter-Dependent (LTIPD) and Linear Periodically Time-Varying (LPTV) systems using lifting technique. Almost the same analysis conditions for parametrically affine discrete-time LTIPD/LPTV systems as the ones shown in this note have already been proposed in the literature, we thus focus on the simple derivations of the conditions using only Elimination lemma. To this end, a variant of extended LMI formulation, whose dimensional sizes are slightly larger than the conventional formulation with additional auxiliary matrices, is proposed in this note. It is also shown that our derived variant directly leads to a parametrically multi-affine extended LMI formulation for our addressed problem.

DOI： 10.1016/j.ifacol.2023.10.074

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Support technology for preventive maintenance of control systems based on fail-soft concept 査読有り国際誌

Suyama K., Sebe N.

IFAC-PapersOnLine 56 ( 2 ) 5566 - 5572 2023年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

In this paper, as a support technology for safely performing preventive maintenance of LTI control systems, we propose a safe shutdown process for a maintenance-object subsystem. The proposed process is based on the “fail-soft” concept that the subsystem gradually makes its way toward a complete stoppage and the overall control system is lead to a safe situation by using the remaining function in the overall system including the subsystem. The discussion in this paper can be applied to a return process to the normal operation.

DOI： 10.1016/j.ifacol.2023.10.458

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Robustness of disturbance observer based servo systems 査読有り国際誌

Shikada K., Sebe N., Sato M.

IFAC-PapersOnLine 56 ( 2 ) 11570 - 11577 2023年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

This paper gives a theoretical analysis of the robustness of servo systems with disturbance observers. The disturbance observers have been used as an easy way to enhance the robustness of servo systems because of their simple structure. However, the effectiveness has yet to be theoretically proved. Therefore, this paper aims to clarify the advantage of the disturbance observer. This paper considers the servo system consisting of a servo compensator and a disturbance observer. The servo system has robustness in suppressing the response variations against the system uncertainties. It is theoretically shown that the robustness comes from the systems having zeros of multiplicity two at s = 0, while the systems are type-1 servo systems. A numerical example is provided to confirm the theoretical result and to demonstrate the effectiveness of disturbance observers.

DOI： 10.1016/j.ifacol.2023.10.454

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Lower Bound Analysis of L<inf>p+</inf> Induced Norm for LTI Systems 査読有り国際誌

Ebihara Y., Sebe N., Waki H., Hagiwara T.

IFAC-PapersOnLine 56 ( 2 ) 2425 - 2430 2023年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

In this paper, we focus on the lower bounds of the Lp (p ∈ [1, ∞), p = ∞) induced norms of continuous-time LTI systems where input signals are restricted to be nonnegative. This induced norm, called the Lp+ induced norm, is particularly useful for the stability analysis of nonlinear feedback systems constructed from linear systems and static nonlinearities where the nonlinearities provide only nonnegative signals for the case p = 2. To have deeper understanding on the Lp+ induced norm, we analyze its lower bounds with respect to the standard Lp induced norm in this paper. As the main result, we show that the Lp+ induced norm of an LTI system cannot be smaller than the Lp induced norm scaled by 2(1−p)/p for ∈ [1, ∞) (scaled by 2−1 for p = ∞). On the other hand, in the case where p = 2, we further propose a method to compute better (larger) lower bounds for single-input systems via reduction of the lower bound analysis problem into a semi-infinite programming problem. The effectiveness of the lower bound computation method, together with an upper bound computation method proposed in our preceding paper, is illustrated by numerical examples.

DOI： 10.1016/j.ifacol.2023.10.1218

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Dependability management of control systems via controller design 査読有り国際誌

Suyama K., Miura R., Sebe N.

IFAC-PapersOnLine 56 ( 2 ) 5542 - 5547 2023年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

We propose dependability management of control systems via controller design under the authorization by international standards. We can obtain a controller achieving a given target value of availability and the optimal performance in the normal operation. Furthermore, we show quantitatively the existence of the trade-off between the availability target and control performance first time ever. This is meaningful for the further developments in fault-tolerant control.

DOI： 10.1016/j.ifacol.2023.10.451

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Switching L2 gain for analyzing successive system switches 査読有り

Suyama K., Sebe N.

2023 European Control Conference, ECC 2023 2239 - 2244 2023年06月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Romania Bucharest 2023年06月13日 - 2023年06月16日

In this paper, we consider a new switching L2 gain for evaluating the magnitude of successive system switches, and focus on its upper bound obtained simply as an analysis index. Furthermore, we simultaneously and simply design the initial states of newly-activated controllers at all system switches to establish the potential practicality as a design index of the upper bound. This is a novel approach to initial state design.

DOI： 10.23919/ECC57647.2023.10178211

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Relation between disturbance observer and model error compensator 査読有り

Shikada K., Sebe N.

Proceedings of 2023 SICE International Symposium on Control Systems, SICE ISCS 2023 64 - 69 2023年03月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Kusatsu 2023年03月08日 - 2023年03月11日

This paper clarifies the relationship between the disturbance observer and the model error compensator. The model error compensator proposed by Okajima et al. (2013) compensates for the error between the output of the nominal plant model and the measurement outputs of the actual plant. On the other hand, the disturbance observer was first proposed to cancel out the effect of the disturbance by using the inverse model of the plant. Okajima et al. (2013) claim that the model error compensator differs from the disturbance observer because it does not use an inverse model, which is an advantage of the model error compensator. However, Ohnishi et al. (1996) proposed the Luenbergar observer-based disturbance observer, which does not use an explicit inverse model. Therefore, this paper shows that the disturbance observer is a type of model error compensator that uses a nominal model. Furthermore, it is shown that the observer gain of the disturbance observer determines the parameters of the model error compensator.

DOI： 10.23919/SICEISCS57194.2023.10079207

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Conversion From Unstructured LPV Controllers to Observer-Structured LPV Controllers 査読有り国際誌

Masayuki Sato, Noboru Sebe

Proceedings of the IEEE 61st Conference on Decision and Control 3297 - 3302 2022年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Mexico Cancun 2022年12月06日 - 2022年12月09日

This note addresses the conversion problem from unstructured Linear Parameter-Varying (LPV) controllers, which are designed a priori for LPV plant systems possessing parametric uncertainties as well as scheduling parameters, to observer-structured LPV controllers. In general, LPV controllers designed using parametrically dependent Linear Matrix Inequalities (LMIs) have no special structures. On this issue, we propose "observer-structured LPV controllers"which can be defined even for LPV plant systems without knowledge of the nominal state-space matrices of the LPV plant systems, and we address the conversion problem from a priori designed unstructured LPV controllers to observer-structured LPV controllers in order to embed observer property without changing controllers' input-to-output properties. To this end, we first parametrize the state-space matrices of observer-structured LPV controllers using those of the unstructured LPV controllers, single free matrices and constant state transformation matrices, and then give a formulation in terms of parametrically multi-affine LMIs to obtain the optimal constant state transformation matrices with respect to induced L2/l2 norm from external input to plant state estimation errors. A numerical example is introduced to demonstrate the usefulness of our propositions.

DOI： 10.1109/CDC51059.2022.9992585

DOI： 10.1109/CDC51059.2022.9992585

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Reduction of steady-state error for a ramp input in type 1 servo systems 査読有り国際誌

Honoka Shimatate, Kana Shikada, Noboru Sebe

2022 61st Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2022 924 - 929 2022年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Kumamoto 2022年09月06日 - 2022年09月06日

This paper considers the reduction of steady-state error for ramp inputs in type 1 servo systems. It is well-known that type 2 servo systems track both step and ramp inputs. However, their transient responses for step inputs are oscillatory. On the other hand, in some applications, type 1 servo systems are required to track, but not exactly track, ramp inputs. For such systems, the characteristics between types 1 and 2 servo systems are desired. For such a problem, this paper proposes a weight function used for H∞ control theory in the sensitivity reduction problem. The proposed weight function reduces the gain of the sensitivity function in the low-frequency range. This allows small steady-state error for ramp inputs and makes the characteristics of the designed type 1 servo systems closer to type 2 servo systems. The effectiveness of the proposed method is demonstrated through numerical examples.

DOI： 10.23919/SICE56594.2022.9905769

DOI： 10.23919/SICE56594.2022.9905769

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Projection onto the Set of Rank-Constrained Structured Matrices for Reduced-Order Controller Design 査読有り国際誌

Nagahara M., Iwai Y., Sebe N.

Algorithms 15 ( 9 ) 2022年09月

記述言語：英語掲載種別：研究論文（学術雑誌）

In this paper, we propose an efficient numerical computation method of reduced-order controller design for linear time-invariant systems. The design problem is described by linear matrix inequalities (LMIs) with a rank constraint on a structured matrix, due to which the problem is non-convex. Instead of the heuristic method that approximates the matrix rank by the nuclear norm, we propose a numerical projection onto the rank-constrained set based on the alternating direction method of multipliers (ADMM). Then the controller is obtained by alternating projection between the rank-constrained set and the LMI set. We show the effectiveness of the proposed method compared with existing heuristic methods, by using 95 benchmark models from the COMPL (Formula presented.) ib library.

DOI： 10.3390/a15090322

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Design of Observer-Structured H<inf>∞</inf> Flight Controllers Converted from Unstructured Conventional H<inf>∞</inf> Flight Controllers 査読有り国際誌

Masayuki Sato, Noboru Sebe

IFAC-PapersOnLine (ROCOND2022) 55 ( 25 ) 19 - 24 2022年08月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Kyoto (online) 2022年08月30日 - 2022年09月02日

We address the conversion problem from a priori designed unstructured Linear Time-Invariant (LTI) controllers to observer-structured LTI controllers, whose structure is similar to but is not exactly the same as the so-called “Luenberger observer-based controllers”, for Linear Parameter-Varying (LPV) or LTI Parameter-Dependent (LTIPD) plant systems. For this problem, we propose a method by designing appropriate state transformation matrices which minimize the errors between plant systems' states and transformed controllers' states for external inputs via parametrically multi-affine Linear Matrix Inequality (LMI) conditions. The proposed method embeds existing LTI controllers with the ability of observers while their control performance is unchanged. We introduce a numerical example and illustrate the usefulness of our method by embedding observer property to an a priori designed H∞ flight controller.

DOI： 10.1016/j.ifacol.2022.09.317

DOI： 10.1016/j.ifacol.2022.09.317

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Selection of the estimation model for robust observer-based controller against plant uncertainties 査読有り国際誌

Kana Shikada, Noboru Sebe, Masayuki Sato

IFAC-PapersOnLine (ROCOND2022) 55 ( 25 ) 193 - 198 2022年08月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Kyoto (online) 2022年08月30日 - 2022年09月02日

This paper is concerned with the design of robust controllers with observers. In general, the nominal model is selected as the state-space model for the observer to estimate the states even if the plant has uncertainties. However, the properness of this strategy is ambiguous. This paper evaluates the properness of selecting the nominal model for state estimation of the plant with uncertainties. Sato (2018a) proposed a new type of controller so-called observer-structured controller. The controller introduces additional freedom for selecting the state-space model used for the state estimation. With this type of controller, this paper demonstrates that the adequate selection of estimation model improves the closed-loop control performance through numerical examples.

DOI： 10.1016/j.ifacol.2022.09.346

DOI： 10.1016/j.ifacol.2022.09.346

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Conversion From Unstructured LTI Controllers to Observer-Structured Ones for LPV Systems 査読有り国際誌

Masayuki Sato, Noboru Sebe

Frontiers in Control Engineering 3 2022年08月

Augmented switching L<inf>2</inf> gain for evaluating the smoothness of transient responses after a system switch 査読有り

Suyama K., Sebe N.

2022 European Control Conference, ECC 2022 1097 - 1102 2022年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

United Kingdom London 2022年07月12日 - 2022年07月15日

In this paper, we focus on the smoothness of transient responses after a system switch to propose a new augmented switching L2 gain including the evaluation of their differential. Moreover, we apply it to the initial state design of a newly-activated controller at a controller switch to establish its potential practicality as a design index.

DOI： 10.23919/ECC55457.2022.9838245

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L<inf>2+</inf> Induced Norm Analysis of Continuous-Time LTI Systems Using Positive Filters and Copositive Programming 査読有り国際誌

Ebihara Y., Motooka H., Waki H., Sebe N., Magron V., Peaucelle D., Tarbouriech S.

2022 European Control Conference, ECC 2022 1385 - 1390 2022年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

United Kingdom London 2022年07月12日 - 2022年07月15日

This paper is concerned with the analysis of the L2 induced norm of continuous-time LTI systems where the input signals are restricted to be nonnegative. This induced norm is referred to as the L2+ induced norm in this paper. It has been shown very recently that the L2+ induced norm is particularly useful for the stability analysis of nonlinear feedback systems constructed from linear systems and static nonlinearities where the nonlinear elements only provide nonnegative signals. For the upper bound computation of the L2+ induced norm, an approach with copositive programming has also been proposed. It is nonetheless true that this approach becomes effective only for multi-input systems, and for single-input systems this approach does not bring any improvement over the trivial upper bound, the standard L2 norm. To overcome this difficulty, we newly introduce positive filters to increase the number of positive signals. This enables us to enlarge the size of the copositive multipliers so that we can obtain better (smaller) upper bounds with copositive programming. Keywords: nonnegative signal, L2+ induced norm, positive filter, copositive programming

DOI： 10.23919/ECC55457.2022.9838085

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線形時不変パラメータ依存プラントに対する既設計の非構造化制御器からオブザーバ構造型制御器への変換査読有り

佐藤昌之, 瀬部昇

計測自動制御学会論文集 ( 公益社団法人計測自動制御学会 ) 58 ( 5 ) 255 - 261 2022年05月

記述言語：日本語掲載種別：研究論文（学術雑誌）

<p>This paper considers the conversion problem from strictly proper non-structured Linear Time-Invariant (LTI) controllers, which are designed <i>a priori</i>, to strictly proper “observer-structured LTI controllers”, whose structure is similar to but not exactly the same as the so-called “Luenberger observer-based LTI controllers”, for LTI Parameter-Dependent (LTIPD) plant systems. We parametrize the state-space matrices of the observer-structured controllers with those of the non-structured controllers, one free matrix and a state transformation matrix, and propose a method to obtain the optimal state transformation matrix with respect to the convergence of non-zero initial plant state. We also clarify the relation between our method and an existing one for full-order controllers for LTI plant systems.</p>

DOI： 10.9746/sicetr.58.255

Development of Support Programs for Solving BMI Problems by Overbounding Approximation Method 査読有り国際誌

Jiulin Zhu, Noboru Sebe

2022 SICE International Symposium on Control Systems 9 - 15 7 pages 2022年03月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Tokyo 2022年03月07日 - 2022年03月10日

A support program that implements the overbounding approximation method for MATLAB and YALMIP is developed. The overbounding approximation is one of the methods that provide sufficient LMI constraints for the given BMI constraints. With this method, one can obtain an approximate solution to the given BMI problem. However, it is not easy for ordinary users to implement the method to solve BMI problems. To overcome the difficulty, we provide a function that finds initial solutions for optimization and solves BMI problems automatically. This function enables users to obtain solutions for the BMI problem easily.

DOI： 10.23919/SICEISCS54350.2022.9754368

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周波数領域における拘束条件下での入力行列内のパラメータ推定査読有り

佐藤昌之, 瀬部昇

計測自動制御学会論文集 ( 計測自動制御学会 ) 58 ( 2 ) 100 - 104 2022年02月

Design of safe preventive maintenance procedure for control systems 査読有り国際誌

Suyama K., Sebe N.

Conference on Control and Fault-Tolerant Systems, SysTol 2021 37 - 43 2021年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

France St Raphael 2021年09月29日 - 2021年10月01日

By applying the initial state design using a state-dependent switching L2 gain to the safe maintenance procedure presented before, we improve the safety of transitions between operating states to bring the procedure to completion as a support technology for safe and partially-performed preventive maintenance of linear time-invariant control systems.

DOI： 10.1109/SysTol52990.2021.9595792

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A Dense Optical Flow Estimation Based on Dynamical System Approach under Intensity Variation Violating the Conservation Law 査読有り国際誌

Nakamura A., Sebe N., Enokida S., Nobuyama E.

2021 60th Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2021 472 - 477 2021年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Tokyo 2021年09月08日 - 2021年09月10日

Optical flow is a vector that represents the motion of objects in images. To estimate the optical flow, most of the optical flow estimation methods assume the intensity conservation law. The estimation methods based on a dynamical system approach [3], [4] also use the same assumption. Therefore, these methods might not be able to estimate correctly if the intensity conservation law is violated by various factors. A estimation model at a pixel considering the illumination change was proposed in [7] to improve the estimation accuracy in such situations. This paper proposes a new dense estimation model with the intensity correction quantity to overcome the estimation in the illumination change and the occlusion. Furthermore, this paper proposes to estimate the optical flow with the Kalman filter or the Kalman filter with the sparse constraint to correction quantity. Using the sparse constraint, the correction quantity becomes non-zero only near the flow boundaries. Accordingly, the improvement of estimation accuracy can expect. The effectiveness of the proposed models is demonstrated through numerical examples.

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Robust observer-based controller against plant uncertainties 査読有り国際誌

Shikada K., Sebe N., Sato M.

2021 60th Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2021 1196 - 1201 2021年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Tokyo 2021年09月08日 - 2021年09月10日

This paper concerns a method of constructing observers for the plant with uncertainties. In a conventional design, the nominal system matrix is chosen as the system matrix of the observer for the system with/without the uncertainties. However, the rationale of this strategy is ambiguous. This paper investigates the degree of freedom in selecting the system matrix of the observer. The observer-structured controllers designed with freedom of the selection are evaluated in the H2 control and estimation performances.

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Safety Design of Control Systems According to International Standards 査読有り国際誌

Koichi Suyama, Noboru Sebe

Proceedings of 2021 European Control Conferenc 1305 - 1310 2021年07月

Reduction of SISO H-infinity output feedback control problem 査読有り国際誌

Waki H., Ebihara Y., Sebe N.

Linear Algebra and Its Applications 610 ( 1 ) 321 - 378 2021年02月

記述言語：英語掲載種別：研究論文（学術雑誌）

We consider the linear matrix inequality (LMI) problem of H output feedback control problem for a generalized plant whose control input, measured output, disturbance input, and controlled output are scalar. We provide an explicit form of the optimal value. This form is the unification of some results in the literature of H performance limitation analysis. To obtain the form of the optimal value, we focus on the non-uniqueness of perpendicular matrices, which appear in the LMI problem. We use the null vectors of invariant zeros associated with the dynamical system for the expression of the perpendicular matrices. This expression enables us to reduce and simplify the LMI problem. Our approach uses some well-known fundamental tools, e.g., the Schur complement, Lyapunov equation, Sylvester equation, and matrix completion. We use these techniques for the simplification of the LMI problem. Also, we investigate the structure of dual feasible solutions and reduce the size of the dual. This reduction is called a facial reduction in the literature of convex optimization. ∞ ∞

DOI： 10.1016/j.laa.2020.09.034

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On Gain-Scheduled State-Feedback Controller Synthesis with Quadratic Stability Condition 査読有り国際誌

Ebihara Y., Sebe N., Waki H.

Proceedings of 59th IEEE Conference on Decision and Control 4 ( 3 ) 2020年12月

A New Optical Flow Estimation Based on Dynamical System Approach with Intensity Variation Violating the Conservation Law 査読有り国際誌

Nakamura A., Sebe N., Enokida S., Nobuyama E.

2020 59th Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2020 967 - 972 2020年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Thailand (online) Chiang Mai 2020年09月23日 - 2020年09月26日

Optical flow is a vector that represents the motion of objects in images. The dynamical system approach to optical flow estimation [3] was proposed as one of the optical flow estimation methods. Most of the optical flow estimation methods are based on the intensity conservation law. Therefore, these estimation methods might not be able to estimate correctly if the intensity conservation law is violated by various factors. This paper proposes a new estimation model for images in which the image intensity is not maintained after moving objects in images. The proposed method can estimate not only the optical flow and its spatial gradients but also the intensity variation and its spatial gradients that do not follow the intensity conservation law. In addition, this paper focuses on the possibility of the optical flow estimation from the perspective of the observability. The effectiveness of the proposed model is demonstrated through numerical examples.

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Robust fault-tolerant servo system against sensor failure and plant uncertainties 査読有り国際誌

Shikada K., Sebe N., Suyama K., Indriawati K.

2020 59th Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2020 1886 - 1891 2020年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Thailand (online) Chiang Mai 2020年09月23日 - 2020年09月26日

This paper concerns with a design of robust fault-tolerant servo systems against sensor failures and plant uncertainties. The method already exists which estimates sensor failures with disturbance observer, and, constitutes a fault-tolerant control system. In this method, generally the optimal regulator theory is used to design a controller. However, this approach is not easy to consider the robustness against plant uncertainties. In this paper, a method for designing a robust fault-tolerant controller is proposed. This method enables us to consider the robustness by applying H∞ control theory. The effectiveness of the proposed design procedure is demonstrated by a numerical example.

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Improvement of Convergence of the Overbounding Approximation Method for BMI problems by Regularization Term 査読有り国際誌

Azumi K., Sebe N.

2020 59th Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2020 1880 - 1885 2020年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Thailand (online) Chiang Mai 2020年09月23日 - 2020年09月26日

This paper concerns with the regularization term for the overbounding approximation method. The overbounding approximation is one of the methods for solving bilinear matrix inequality (BMI) problems, but the overbounding approximation has problems about its convergence. This paper proposed a new weight parameters of the regularization terms to improve the convergence.

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A safety assessment framework of control systems according to international standards 査読有り国際誌

Suyama K., Sebe N.

Asian Journal of Control 22 ( 5 ) 1741 - 1754 2020年09月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2019 Chinese Automatic Control Society and John Wiley & Sons Australia, Ltd In this paper, we propose an assessment framework for the safety function implemented in a controller according to international standards on safety. Such a function can prevent events where physical values in a control system deviate from the normal operating range, to the fullest extent possible. Therefore, it can decrease the frequency of demand occurrences on externally implemented safety-related systems and supplement them in risk reduction required by the international standards on safety, such as IEC 61508. In the proposed framework, by evaluating the possibility that the deviations occur because of the true effects of a failure/restoration by using the switching L2 gain for analyzing the fluctuations in transient responses after an unpredictable system switch, we can obtain the demand frequency as an assessment result.

DOI： 10.1002/asjc.2131

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Characterization of the dual problem of linear matrix inequality for H-infinity output feedback control problem via facial reduction 査読有り国際誌

Waki H., Sebe N.

Mathematics of Control, Signals, and Systems 32 ( 3 ) 361 - 384 2020年07月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2020, The Author(s). This paper deals with the minimization of H∞ output feedback control. This minimization can be formulated as a linear matrix inequality (LMI) problem via a result of Iwasaki and Skelton 1994. The strict feasibility of the dual problem of such an LMI problem is a valuable property to guarantee the existence of an optimal solution of the LMI problem. If this property fails, then the LMI problem may not have any optimal solutions. Even if one can compute parameters of controllers from a computed solution of the LMI problem, then the computed H∞ norm may be very sensitive to a small change of parameters in the controller. In other words, the non-strict feasibility of the dual tells us that the considered design problem may be poorly formulated. We reveal that the strict feasibility of the dual is closely related to invariant zeros of the given generalized plant. The facial reduction is useful in analyzing the relationship. The facial reduction is an iterative algorithm to convert a non-strictly feasible problem into a strictly feasible one. We also show that facial reduction spends only one iteration for so-called regular H∞ output feedback control. In particular, we can obtain a strictly feasible problem by using null vectors associated with some invariant zeros. This reduction is more straightforward than the direct application of facial reduction.

DOI： 10.1007/s00498-020-00261-z

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Initial state design for suppressing undesirable effects of controller switches 査読有り国際誌

Suyama K., Sebe N.

IFAC-PapersOnLine 53 ( 2 ) 6452 - 6458 2020年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Germany (online) Berlin 2020年07月11日 - 2020年07月17日

We propose a new initial state design procedure for a newly-activated controller at a controller switch. By minimizing the value of the state-dependent switching L2 gain presented in this paper, we can obtain the optimal initial state for suppressing the difference between the actuality that a controller switch occurs and the virtual situation where it does not occur.

DOI： 10.1016/j.ifacol.2020.12.1788

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Learning Koopman operator under dissipativity constraints 査読有り国際誌

Hara K., Inoue M., Sebe N.

IFAC-PapersOnLine 53 ( 2 ) 1169 - 1174 2020年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Germany (online) Berlin 2020年07月11日 - 2020年07月17日

This paper addresses a learning problem for nonlinear dynamical systems with incorporating any specified dissipativity property. The nonlinear systems are described by the Koopman operator, which is a linear operator defined on the infinite-dimensional lifted state space. The problem of learning the Koopman operator under specified quadratic dissipativity constraints is formulated and addressed. The learning problem is in a class of the non-convex optimization problem due to nonlinear constraints and is numerically intractable. By applying the change of variable technique and the convex overbounding approximation, the problem is reduced to sequential convex optimization and is solved in a numerically efficient manner. Finally, a numerical simulation is given, where high modeling accuracy achieved by the proposed approach including the specified dissipativity is demonstrated.

DOI： 10.1016/j.ifacol.2020.12.1327

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On Gain-Scheduled State-Feedback Controller Synthesis with Quadratic Stability Condition 査読有り国際誌

Ebihara Y., Sebe N., Waki H.

IEEE Control Systems Letters 4 ( 3 ) 662 - 667 2020年07月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2017 IEEE. This letter shows that, as long as continuous-time linear parameter-varying (LPV) systems are concerned, quadratic-stability-based gain-scheduled state-feedback controller synthesis offers no advantage over quadratic-stability-based fixed (parameter-independent) state-feedback controller synthesis in typical control performance specifications. We derive this counterintuitive result by properly extending the previous results on the robust versions of Finsler's lemma and the elimination lemma. We also show that this counterintuitive result is continuous-time LPV system specific, and in the discrete-time LPV system case quadratic-stability-based gain-scheduled state-feedback controller synthesis does bring improvement. These results give a proper warning about the effectiveness of the quadratic-stability-based gain-scheduled state-feedback controller synthesis.

DOI： 10.1109/LCSYS.2020.2991480

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Reduction of H-infinity state feedback control problems for the MIMO servo systems 査読有り国際誌

Waki H., Sebe N.

Asian Journal of Control 22 ( 3 ) 1025 - 1037 2020年05月

記述言語：英語掲載種別：研究論文（学術雑誌）

We deal with H-infinity state feedback control problem for the multi-input-multi-output (MIMO) servo system and discuss the advantages of the facial reduction (FR) to the resulting linear matrix inequality (LMI) problems. In fact, as far as our usual setting, the dual of the LMI problem is not strictly feasible because the generalized plant has always stable invariant zeros. Thus FR is available to such LMI problems, and we can reduce and simplify the original LMI problem to a smaller-size LMI problem. As a result, we observe that the numerical performance of the SDP solvers is improved. Also, as a by-product, we obtain the best performance index of the reduced LMI problem with a closed-form expression. This helps the H-infinity performance limitation analysis. Another contribution is to reveal that the resulting LMI problem obtained from H-infinity control problem has a finite optimal value, but no optimal solutions under an additional assumption. This is also confirmed in the numerical experiment of this paper. FR also plays an essential role in this analysis.

DOI： 10.1002/asjc.1985

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Fault tolerant method on position cascade control of Dc servo system 査読有り国際誌

Indriawati K., Sebe N.

Mechatronic Systems and Control 48 ( 2 ) 144 - 151 2020年04月

記述言語：英語掲載種別：研究論文（学術雑誌）

The fault of the positioning servo system due to actuator and sensor faults can endanger users and the surrounding environment; even the existing control system has a good performance to position precisely something, such as a position cascade control system. In this paper, a fault tolerant control (FTC) system has been implemented to tolerate faults automatically when the faults on actuator and sensor component of DC modular servo system have occurred. The proposed design consisted of both observers working to estimate actuator fault and later sensor fault, as well as the fault compensation mechanism that has functioned as an occurred fault corrector. The results have showed that FTC system could maintain the performance of the cascade control system of a DC modular servo system with the values of maximum overshoot, settling time, and error steady state that have been smaller than the ones without fault compensation.

DOI： 10.2316/J.2020.201-0094

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半正定値計画によるH∞性能限界解析招待有り

蛯原義雄, 脇隼人, 瀬部昇

計測と制御 ( 公益社団法人計測自動制御学会 ) 59 ( 3 ) 218 - 225 2020年03月

離散時間線形時不変システム解析のための外部非負システムの構成と低次元化査読有り

蛯原義雄, 瀬部昇, 増淵泉, 脇隼人, 管野政明, 椿野大輔

システム制御情報学会論文誌 ( 一般社団法人システム制御情報学会 ) 32 ( 7 ) 284 - 293 2019年07月

記述言語：日本語掲載種別：研究論文（学術雑誌）

<p>This paper is concerned with the analysis of discrete-time LTI systems via construction of associated externally positive systems. Recently, the authors established a construction method of an externally positive system whose impulse response is given by the square of the original discrete-time LTI SISO system to be analyzed. This externally positive system allows us to characterize the <i>H</i><sub>2 </sub>norm of the original system by means of the closed-form <i>l<sub>∞</sub></i>-induced norm characterization of externally positive systems. It is nonetheless true that, for the original system of order <i>n</i>, the order of the resulting externally positive system is <i>n</i><sup>2</sup>, incurring a drastic increase in computational burden of computer-aided analysis and synthesis. With this important issue in mind, in this paper, we show that the order can be reduced down to <i>n</i>(<i>n</i>+1)<i>/</i>2 by using the elimination and duplication matrices that are intensively studied by J. R. Magnus in the 80's. In addition to the computational complexity reduction for the aforementioned <i>H</i><sub>2 </sub>analysis, we show that such construction of externally positive systems with reduced order is quite effective in semidefinite-programming-based peak value analysis of impulse responses of general LTI systems.</p>

DOI： 10.5687/iscie.32.284

その他リンク： https://ci.nii.ac.jp/naid/130007728846

Initial state design for controller switches by using state-dependent switching L2 gain 査読有り国際誌

Suyama K., Sebe N.

2019 18th European Control Conference, ECC 2019 1257 - 1262 2019年06月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Italy Naples 2019年06月25日 - 2019年06月28日

© 2019 EUCA. We propose a new method for designing the initial state of a newly-activated controller at a controller switch. By minimizing the value of a state-dependent switching L2gain through a linear matrix inequality problem, it can provide the optimal initial state for suppressing the fluctuations in transient responses after the switch.

DOI： 10.23919/ECC.2019.8796131

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Minimal order observer based H-infinity controller design based on overbounding approximation method 査読有り国際誌

Kayo S., Nohmi A., Sebe N., Sato M.

2019 12th Asian Control Conference, ASCC 2019 167 - 172 2019年06月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Kitakyushu 2019年06月10日 - 2019年06月12日

© 2019 JSME. In this paper, the minimal order observer based H∞ controller design is studied. The state space representation of the minimal order observer based controller is complicated and involves the product and quadratic terms of the decision variable matrices, i.e., the state feedback and observer gains. To make the design problem as a bilinear matrix inequality (BMI) problem, we represent the minimal order observer based controller by a descriptor representation, where the decision variable matrices are affinely involved. This descriptor representation enables us to design controllers by applying the overbounding approximation method for general BMI problems. The effectiveness of the proposed design procedure is demonstrated by a numerical example.

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Switching L2 gain for evaluating the fluctuations in transient responses after an unpredictable system switch 査読有り国際誌

Suyama K., Sebe N.

International Journal of Control 92 ( 5 ) 1084 - 1093 2019年05月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group. We propose a new switching L2 gain for evaluating the fluctuations in transient responses after an unpredictable switch, such as a switch caused by a failure in a control device occurring in the normal operation, between two linear time-invariant systems. We also present L2 gain conditions that enable us to compute the value of the proposed switching L2 gain. We then theoretically establish its applicability as an analysis index. Furthermore, by applying the proposed gain to switching matrix design, we show its potential applicability as a design index.

DOI： 10.1080/00207179.2017.1381884

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Application of facial reduction to H-infinity state feedback control problem 査読有り国際誌

H. Waki, N. Sebe

International Journal of Control 92 ( 2 ) 303 - 316 2019年02月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group. One often encounters numerical difficulties in solving linear matrix inequality (LMI) problems obtained from H ∞ control problems. For semidefinite programming (SDP) relaxations for combinatorial problems, it is known that when either an SDP relaxation problem or its dual is not strongly feasible, one may encounter such numerical difficulties. We discuss necessary and sufficient conditions to be not strongly feasible for an LMI problem obtained from H ∞ state feedback control problems and its dual. Moreover, we interpret the conditions in terms of control theory. In this analysis, facial reduction, which was proposed by Borwein and Wolkowicz, plays an important role. We show that the dual of the LMI problem is not strongly feasible if and only if there exist invariant zeros in the closed left-half plane in the system, and present a remedy to remove the numerical difficulty with the null vectors associated with invariant zeros in the closed left-half plane. Numerical results show that the numerical stability is improved by applying it.

DOI： 10.1080/00207179.2017.1351625

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State-Dependent Switching L2 Gain for Analyzing the Fluctuations in Transient Responses after a System Switch 査読有り国際誌

Koichi Suyama, Noboru Sebe

Proceedings of 57th IEEE Conference on Decision and Control 6263 - 6268 2018年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

U.S.A. Miami Beach 2018年12月17日 - 2018年12月19日

© 2018 IEEE. We propose a state-dependent switching mathcal{L}-{2} gain for analyzing the fluctuations in transient response after an unpredictable switch between two linear time-invariant systems. Its value depends on the state of a pre-switch system at a switching time. Thus, it enables us to theoretically discuss the effects of the situation at a switching time on the fluctuations in transient responses after the switch. For example, its value distribution in the state space of a pre-switch system can be used for evaluating the dangerous extent of the situation at an occurrence time of a control device failure.

DOI： 10.1109/CDC.2018.8618974

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Search Direction in Successive Linearization of Bilinear Matrix Inequality Problems 査読有り国際誌

Tomoki Okayama, Noboru Sebe

2018 International Conference on Information and Communication Technology Robotics, ICT-ROBOT 2018 6 pages 2018年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Korea Busan 2018年09月07日 - 2018年09月09日

© 2018 IEEE. This paper proposes an alternative successive linearization method which determines the search direction previously to the optimization of decision variables. The proposed method preserves the size of matrix inequality constraint to avoid the increase of the computational consumption.

DOI： 10.1109/ICT-ROBOT.2018.8549906

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Sequential Convex Overbounding Approximation Method for Bilinear Matrix Inequality Problems 査読有り

Noboru Sebe

IFAC symposium on Robust Control Design 51 ( 25 ) 102 - 109 IFAC paper online 2018年09月

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Brazil Florianopolis 2018年09月03日 - 2018年09月05日

© 2018 This paper concerns with the overbounding method for solving the bilinear matrix inequality (BMI) problem. The overbounding method is essentially the same as the difference of convex optimization approach and the inner approximation method. The unified view of these methods is provided. This paper also proposes a new overbounding algorithm based on the less conservative overbounding approximation and the matrix decomposition.

DOI： 10.1016/j.ifacol.2018.11.089

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State assignment method for improvement of transient response caused by controller switching 査読有り国際誌

Nakano K., Sebe N., Deguchi S., Suyama K.

IFAC Symposium on Robust Control Design 51 ( 25 ) 365 - 370 IFAC-PapersOnLine 2018年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Brazil Florianopolis 2018年09月03日 - 2018年09月05日

© 2018 In this paper, the suppression of undesirable transient responses caused by controller switching is considered. In some cases, we switch the feedback and the observer gains in order to improve the control performance. However, such switching causes large disturbed transient response. To suppress such undesirable transient response, we propose to assign the state of the dynamical controller. This paper shows that it can be further suppressed by attaching an observer in order to suppress the transient response caused by switching, even in the case that all the states can be measured directly. The proposed assignment rule is based on the observability gramian of the post-switching closed loop system.

DOI： 10.1016/j.ifacol.2018.11.134

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Improving the Accuracy of Dynamical System Based Optical Flow Estimation by Central Difference Discretization of Time Derivative 査読有り国際誌

Yuta Akiyoshi, Noboru Sebe, Shuichi Enokida and Eitaku Nobuyama

4th International Conference on Machine Vision and Machine Learning (MVML'18) MVML107 (7 pages) 2018年08月

Control System Design for Safely Performing Preventive Maintenance 査読有り

Suyama K., Sebe N.

IEEE International Conference on Control and Automation, ICCA 1087 - 1094 2018年06月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

U.S.A. Anchorage 2018年06月12日 - 2018年06月15日

© 2018 IEEE. On the basis of fault-tolerant control theory and switching L2 gain analysis, we propose a new control system design procedure for achieving an operating state suitable for safely performing preventive maintenance of each subsystem, where the safety of the bidirectional transitions between normal operation and an operating state is guaranteed.

DOI： 10.1109/ICCA.2018.8444281

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Strong feasibility of the dual problem of linear matrix inequality for H-infinity output feedback control problem 査読有り国際誌

Waki H., Sebe N.

SICE ISCS 2018 - 2018 SICE International Symposium on Control Systems 47 - 53 2018年03月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Tokyo 2018年03月09日 - 2018年03月11日

© 2018 The Society of Instrument and Control Engineers - SICE. Strong feasibility (a.k.a. strict feasibility) of the dual problem of a given linear matrix inequality (LMI) is an important property to guarantee the existence of an optimal solution of the LMI problem. In particular, the LMI problem may not have any optimal solutions if the dual is not strongly feasible. This implies that the computed solutions by SDP solvers may be meaningless and useless for designing the controllers of H∞ output feedback control problems. The facial reduction is a tool to analyze and reduce such non-strongly feasible problems. We introduce the strong feasibility of the dual and facial reduction and provide the necessary and sufficient condition on the strong feasibility. Furthermore, we reveal that the condition is closely related to invariant zeros in the plant.

DOI： 10.23919/SICEISCS.2018.8330155

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外部非負システムへの変換による離散時間線形時不変システムのH2解析査読有り

蛯原義雄, 瀬部昇, 増淵泉, 脇隼人, 管野政明, 椿野大輔

システム制御情報学会論文誌 ( 一般社団法人システム制御情報学会 ) 31 ( 2 ) 75 - 84 2018年02月

記述言語：日本語掲載種別：研究論文（学術雑誌）

<p>In this paper, we explore <i>H</i><sub>2 </sub>analysis techniques of general, not necessarily positive, discrete-time linear time-invariant (LTI) systems by means of positive system theory. While externally positive systems are a particular class of systems whose impulse responses take only nonnegative values, we often encounter such impulse responses even in the analysis of general LTI systems. A typical example is the computation of the <i>H</i><sub>2 </sub>norm where we focus on squared impulse responses. In view of this observation, we first clarify that we can construct an SISO externally positive system whose impulse response is given by the square of the impulse response of a given SISO LTI system. This system conversion allows us to reduce the <i>H</i><sub>2 </sub>norm computation problem of a general LTI system to the <i>l</i><i><sub>∞</sub></i>-induced norm computation problem (or <i>l</i><sub>1 </sub>problem in short) of the resulting externally positive system. It also turns out that this problem reduction enables us to derive various alternative formulas for the <i>H</i><sub>2 </sub>norm of general discrete-time LTI systems.</p>

DOI： 10.5687/iscie.31.75

その他リンク： https://ci.nii.ac.jp/naid/130006734448

A bias fault estimation of actuators and sensors by optimization with l0 norm constraint 査読有り国際誌

Ichikawa M., Sebe N., Suyama K., Indriawati K.

2017 Asian Control Conference, ASCC 2017 1443 - 1448 2017年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Australia Gold Coast 2017年12月17日 - 2017年12月20日

© 2017 IEEE. This paper proposes a bias fault estimation method by a single observer, which is based on the compress sensing. Fault-tolerant control of systems becomes increasingly important to keep safety of systems. The bias fault estimation is one of the most important technologies in fault-tolerant control theory, especially for passive fault-tolerant servo systems. For the bias fault estimation problem, the disturbance observer approach has been proposed. However, this approach cannot be applied to the estimation of all faults at both actuators and sensors by a single observer. In this paper, a bias fault estimation method based on the compress sensing is proposed. Under the assumption that only one device fault occurs at a time, the bias fault estimation method by a single observer can be formulated as an optimization problem with l0 norm constraint. This paper gives a numerical example to demonstrate the effectiveness of the proposed estimation method.

DOI： 10.1109/ASCC.2017.8287385

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Effectiveness of higher order controllers for uncertain systems 査読有り国際誌

T. Tada, Y. Izumiguchi, N. Sebe

2017 Asian Control Conference, ASCC 2017 582 - 587 2017年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Australia Gold Coast 2017年12月17日 - 2017年12月20日

© 2017 IEEE. This paper demonstrates the effectiveness of higher order controllers for uncertain systems. Gain scheduling control is a powerful control strategy for robust control, if the uncertainty is measurable. If the uncertainty is not measurable, uncertainty might be estimated by using filters. Using such estimation filters gain scheduling controllers can be regarded as higher order controllers. Accordingly, higher order controllers might achieve better performance for uncertain systems. This paper considers a design problem of robust dynamical state feedback, as an example of higher order controller. This paper also demonstrates the effectiveness of it.

DOI： 10.1109/ASCC.2017.8287235

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Reduction of H-infinity state feedback control problems for the servo systems 査読有り国際誌

H. Waki, N. Sebe

2017 Asian Control Conference, ASCC 2017 2244 - 2249 2017年12月

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Australia Gold Coast 2017年12月17日 - 2017年12月20日

© 2017 IEEE. We study the strict feasibility of the linear matrix inequality (LMI) and its dual for H∞ state feedback control problem for the multi-input multi-output (MIMO) servo system. Then we show that weighting functions with unstable zeros improve the numerical accuracy. We discuss the relationship between the zeros in the weighting function and the strict feasibility of the dual LMI. This is closely related to the numerical accuracy of LMI solvers because algorithms implemented in LMI solvers require the strict feasibility for both the LMI and its dual. Furthermore, we provide closed-form expression of the performance limitation when given plants have one or two unstable invariant zeros. The non-strict feasibility of the dual plays an essential role in the expression.

DOI： 10.1109/ASCC.2017.8287524

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Controller Reset Strategy for Anti-Windup Based on Switching L2 Gain Analysis 査読有り

Koichi Suyama,Noboru Sebe

Asian Journal of Control 19 ( 6 ) 1877 - 1890 2017年11月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2017 Chinese Automatic Control Society and John Wiley & Sons Australia, Ltd When the calculated value of a control input approaches its limitations, resets of controllers are often used to prevent windup. However, an automatic reset should only be performed after confirmation that it will not adversely affect the transient performance and lead to another windup. In this study, we apply a switching L 2 gain analysis to a more appropriate evaluation of transient responses after a reset in order to propose an improved strategy for the automatic resets of controllers, such that windup does not accompany resets.

DOI： 10.1002/asjc.1530

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Support technology for safe preventive maintenance of control systems 査読有り国際誌

Koichi Suyama,Noboru Sebe

20th IFAC World Congress (IFAC-PapersOnLine) 50 ( 1 ) 10369 - 10376 (IFAC-PaperOnLine) 2017年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

France Toulouse 2017年07月09日 - 2017年07月14日

© 2017 On the basis of fault-tolerant control theory and switching L 2 gain analysis, we propose a new maintenance support technology to implement an operating state suitable for safely performing preventive maintenance of each subsystem, where the safety of the bidirectional transitions between normal operation and an operating state is guaranteed.

DOI： 10.1016/j.ifacol.2017.08.1690

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Simultaneous estimation of optical flow and its boundaries based on the dynamical system model 査読有り国際誌

Michishita Y., Sebe N., Enokida S., Nobuyama E.

VISIGRAPP 2017 - Proceedings of the 12th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications 6 377 - 385 2017年02月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Portugal Porto 2017年02月27日 - 2017年03月01日

© 2017 by SCITEPRESS - Science and Technology Publications, Lda. Optical flow is a velocity vector which represents the motion of objects in video images. Optical flow estimation is difficult in the neighborhood of flow boundary. To resolve this problem, Sasagawa (2014) proposes a modified dynamical system model in which one assumes that, in the neighborhood of flow boundaries, the brightness flows in the perpendicular direction, and considers the resulting corrections to the brightness constancy constraint. However, in that model, the correction is occurred even in place where the flow is continuous. We propose a new model, which switches the conventional model and the proposed model in Sasagawa (2014). As a result, we expect improvement of the estimate accuracy in place where the flow is continuous. We conduct numerical experiments to investigate the improvements that the proposed model yields in the estimation accuracy of optical flows.

DOI： DOI: 10.5220/0006101303770385

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Switching L2 Gain for Analyzing the Magnitude of a System Switch 査読有り

Koichi Suyama,Noboru Sebe

55th IEEE Conference on Decision and Control 6395 - 6402 2016年12月

Reduction of SDPs in H-infinity Control of SISO Systems and Performance Limitations Analysis 査読有り国際誌

Hayato Waki,Yoshio Ebihara,Noboru Sebe

55th IEEE Conference on Decision and Control 646 - 651 2016年12月

Evaluation of the ease of restarts in fault-tolerant control systems using multiple switching L2 gains 査読有り

Koichi Suyama,Noboru Sebe

Proc. of the 42nd Annual Conference of the IEEE Industrial Electronics Society paper ID: TTC-CSA4-6 (8 pages) 2016年10月

Dual LMI Approach to H-infinity Performance Limitations Analysis of Sensitivity and Complementary Sensitivity Functions 査読有り国際誌

Yoshio Ebihara,Hayato Waki,Noboru Sebe

Proc. of the IEEE Multi-Conference on Systems and Control 1440 - 1445 2016年09月

H-Infinity Performance Limitations Analysis for SISO Systems: A Dual LMI Approach 査読有り国際誌

Yoshio Ebihara,Hayato Waki,Noboru Sebe

54th IEEE Conference on Decision and Control 6629 - 6634 2015年12月

Robust Fuzzy Observer-Based Fault Tolerant Tracking Control for Nonlinear Systems with Simultaneous Actuator and Sensor Faults: Application to a DC Series Motor Speed Drive 査読有り

Katherin Indriawati,Noboru Sebe,Trihastuti Agustinah,A. Jazidie

International Review of Automatic Control 8 ( 6 ) 375 - 385 2015年12月

Tolerance against multiple fault modes and its application to corrective maintenance of faulty actuators in servo systems 査読有り国際誌

Koichi Suyama,Noboru Sebe

20th IEEE International Conference on Emerging Technologies and Factory Automation paper ID: 9 (8 pages) 2015年09月

Application of Facial Reduction to H-infinity State Feedback Control Problem 査読有り国際誌

Hayato Waki,Noboru Sebe

8th IFAC Symposium on Robust Control Design 112 - 118 2015年07月

New Switching L2 Gain Analysis for a Restart with Controller Resets after Maintenance 査読有り国際誌

Koichi Suyama,Noboru Sebe

8th IFAC Symposium on Robust Control Design 348 - 355 2015年07月

Rotation Matrix Optimization with Quaternion 査読有り国際誌

Shogo Katsuki,Noboru Sebe

Proceedings of Asian Control Conference 2015 paper ID:1570074907 (6 pages) 2015年06月

Effects of Diagonal Dominance on Performance of Passive Fault Tolerant Servo Systems 査読有り国際誌

Kenta Toyoda,Noboru Sebe,Koichi Suyama

Proceedings of Asian Control Conference 2015 paper ID:1570074897 (6 pages) 2015年06月

Lower bound analysis of H-infinity performance achievable via decentralized LTI controllers 査読有り国際誌

Yoshio Ebihara,Noboru Sebe

International Journal of Robust and Nonlinear Control 24 ( 16 ) 2423 - 2437 2014年11月

Fault-tolerant servo systems using integrators with variable limits 査読有り国際誌

Koichi Suyama,Noboru Sebe

Proceedings of 2014 IEEE Emerging Technology and Factory Automation 8 pages 2014年09月

Dependability Analysis of Fault-Tolerant Servo Systems Using Limited Integrators 査読有り国際誌

Koichi Suyama,Noboru Sebe

Proceedings of 2014 European Control Conference 2014年06月

Passive Fault Tolerant Servo Control against One Device Failure Out of Sensors and Actuators 査読有り国際誌

Noboru Sebe,Koichi Suyama

Proceedings of 2014 European Control Conference 2014年06月

A Design of Fault-Tolerant Servo Systems against Sensor Failures 査読有り

Noboru Sebe,Kohei Sumida,Koichi Suyama

2nd International Conference on Control and Fault Tolerant Systems 208 - 215 2013年10月

Fault-Tolerant Servo Systems against Sensor Failures using Limited Integrators 査読有り

Koichi Suyama,Noboru Sebe

Proceedings of 2013 European Control Conference 3796 - 3802 2013年07月

Fault-Tolerant Servo Systems against Actuator Failures 査読有り

Noboru Sebe,Koichi Suyama

Proceedings of 7th IFAC Symposium on Robust Control Design 499 - 504 2012年06月

Quasi-Dense Optical Flow Estimation Based on Dynamical System Models 査読有り

Tomoya Fukami, Shuichi Enokida, Noboru Sebe, Eitaku Nobuyama

Proceedings of SICE Annual Conference 2011 802 - 811 2011年09月

L2 gain analysis of linear systems with a single switching 査読有り

Noboru Sebe, Koichi Suyama

International Journal of Robust and Nonlinear Control 23 ( 8 ) 827 - 837 2011年05月

制御レンジからの逸脱に対する制御則の安全性評価査読有り

陶山貢市, 瀨部昇

電子情報通信学会論文誌A J94-A ( 5 ) 350 - 361 2011年05月

Probabilistic safety management of control laws against deviation from normal operating-range 査読有り

Koichi Suyama,Noboru Sebe

2010 Conference on Control and Fault Tolerant Systems 442 - 449 2010年10月

Decentralized Control for Discrete-Time LTI Systems: Lower Bound Analysis of H-infinity Performance Achievable Via LTI Controllers 査読有り

Yoshio Ebihara,Noboru Sebe

2010 American Control Conference 5602 - 5607 2010年07月

安全性を考慮して故障直後の過渡応答の乱れを抑制する制御系設計査読有り

陶山貢市,瀨部昇

システム制御情報学会論文誌 23 ( 4 ) 65 - 73 2010年04月

正常時制御性能と安全性，故障時制御性能との間のバランスを考慮した制御系設計査読有り

陶山貢市,瀨部昇

システム制御情報学会論文誌 22 ( 1 ) 29 - 36 2009年01月

New LMI Characterizations for Discrete-Time Descriptor Systems and Application to Multiobjetive Control System Synthesis 査読有り

Noboru Sebe

17th IFAC World Congress 8821 - 8827 2008年07月

安全性と制御性能のトレードオフを考慮した制御系設計査読有り

陶山貢市,瀨部昇

システム制御情報学会論文誌 21 ( 3 ) 89 - 99 2008年03月

A New Dilated LMI Characterization and Iterative Control System Synthesis 査読有り

瀨部　昇

11th IFAC/IFORS/IMACS/IFIP Symposium on Large Scale Systems: Theory and Applications 2007年07月

Development of Motor Control for Hybrid Electric Vehicles using Gain-Scheduled H-Infinity Control 査読有り

H. Inagaki(Aisin Seiki Co.Ltd),H. Kato(Aisin Seiki Co.Ltd),N. Sebe

2007 SAE World Congress 2007年04月

Unification of Independent and Sequential Procedures for Decentralized Controller Design 査読有り

瀨部　昇

Automatica 43 ( 4 ) 707 - 713 2007年04月

減衰項のある大規模システムのモード分解による一低次元化法査読有り

瀨部昇,延山英沢,高田昌二,宮元慎一

システム制御情報学会論文誌 19 ( 9 ) 365 - 367 2006年09月

Structure of state feedback with k-out-of-m integrity 査読有り

瀨部　昇

5th IFAC Symposium on Robust Control Design 2006年07月

Low gain property of rank deficient state feedback gain with k-out-of-m integrity 査読有り

Noboru Sebe

3rd International Symposium on Systems & Human Science: Complex Systems Approaches for Safety, Security and Reliability (SSR 2006) 2006年03月

Explicit characterization of decentralized coprime factors 査読有り

瀨部　昇

Automatica 40 ( 9 ) 1569 - 1574 2004年09月

Rank deficiency of reliable controllers 査読有り

瀨部　昇

10th IFAC/IFORS/IMACS/IFIP Symposium on Large Scale Systems: Theory and Applications 1 542 - 547 2004年07月

A study on the structure of reliable controllers 査読有り

瀨部　昇

16th International Symposium on Mathematical Theory of Networks and Systems 2004年07月

A unified approach to decentralized controller design 査読有り

瀨部　昇

The 42nd IEEE Conference on Decision and Control 1086 - 1091 2003年12月

Structure of reliable controllers 査読有り

Noboru SEBE,Akinori Mochimaru

1st International Symposium on Systems & Human Science (SSR2003) 167 - 172 2003年11月

古くても役に立つ古典制御

陶山貢市,瀬部昇

計測と制御 ( 未設定 ) 42 ( 4 ) 268 - 276 2003年04月

Explicit characterization of decentralized coprime factors 査読有り

瀨部　昇

Proceedings of 15th IFAC World Congress 2002年07月

Drive Train Vibration and Acoustic Noise Reduction Control of Switched Reluctance Motor for Electric Vehicle 査読有り

H. Inagaki(Aisin Seiki Co.Ltd),H. Kato(Aisin Seiki Co.Ltd),H. Kuzuya(Aisin Seiki Co.Ltd),M. Sugiyama(Aisin Seiki Co.Ltd),N. Sebe,K. Ikeda(Tokushima University)

Future Car Congress 2002 2002年06月

A characterization of solutions to the inverse H-infinity optimal control problem 査読有り

瀨部　昇

40th IEEE Conference on Decision and Control 273 - 278 2001年12月

About Decentralized Feedback: A Survey

Jacques Bernussou,Noboru Sebe

9th IFAC/IFORS/IMACS/IFIP Symposium on Large Scale Systems: Theory and Applications (LSS 2001) ( 未設定 ) 22 - 33 2001年07月

Quadratic Stability Conditions of Linear Systems with Frobenius Norm-Bounded Deiagonal Perturbations 査読有り

Yoshiro Hamada (National Aerospace Laboratory),Seiichi Shin (Univ. Tokyo),Noboru Sebe

Trans. of the Society of Instrument and Control Engineers 36 ( 8 ) 720 - 722 2000年08月

Series representation of systems and its application to robust controller design 査読有り

Yasutaka Tokunaga,Takafumi Akamatsu (Higashi Chikushi Junior Collage),Noboru SEBE

International Symposium of Mathematical Theory of Networks and Systems 2000年06月

むだ時間を含む 1 次遅れ系に対する PID 制御器の部分モデルマッチング法に基づいた設計法査読有り

赤松貴文(東筑紫短期大学),瀬部昇,北森俊行(法政大学)

システム制御情報学会論文誌 13 ( 1 ) 46 - 52 2000年01月

A Design of Controllers for Simultaneous H-infinity Control Problem 査読有り

瀨部　昇

International Journal of Systems Science 30 ( 1 ) 25 - 31 1999年01月

Decentralized H∞ Controller Design 査読有り

瀨部　昇

The 37th IEEE Conference on Decision and Control 2810 - 2815 1998年12月

耐故障性を有する多変数制御系の一設計法ーl-部分インテグリティ条件ー査読有り

濱田吉郎(東京大学),新誠一(東京大学),瀬部昇

計測自動制御学会論文集 34 ( 9 ) 1184 - 1190 1998年09月

A Design of Controllers for Simultaneous H-infinity Control Problem 査読有り

瀨部　昇

Proceedings of 2nd Asian Control Conference ( 2 ) 583 - 586 1997年07月

Relationship Between Decentralized and Centralized Designs in Mixed Sesitivity Problem 査読有り

Ryosuke Koshiba,Seiichi Shin and Noboru Sebe

Proceedings of 35th IEEE Conference on Decision and Control 7 - 8 1996年12月

Diagonal Dominance and Integrity 査読有り

瀨部　昇

Proceedings of 35th IEEE Conference on Decision and Control 1904 - 1909 1996年12月

A Design Method for Fault-Tolerant Control Systems Based on H-infinity Optimization 査読有り

Yoshiro Hamada,Seiichi Shin,Noboru Sebe

Proceedings of 35th IEEE Conference on Decision and Control 1918 - 1919 1996年12月

線形多変数制御系のインテグリティ条件査読有り

瀨部　昇

計測自動制御学会論文集 32 ( 3 ) 329 - 335 1996年03月

対角優勢と正実性査読有り

瀬部昇,北森俊行

計測自動制御学会論文集 31 ( 12 ) 1930 - 1935 1995年12月

Design of Decentralized Stabilizing Controller Based on a Coprime Factorization 査読有り

Noboru Sebe,Toshiyuki Kitamori

Preprints of IFAC LSS '95 ( 1 ) 475 - 480 1995年07月

Invitation to Dissymmetry --- System Invariance and Basic Properties --- 査読有り

Reiko Tanaka,Seiichi Shin and Noboru Sebe

Preprints of IFAC Conference on System Structure and Control 449 - 454 1995年07月

ロバストパフォーマンスを達成する分散型安定化補償器の既約分解表現に基づく設計法査読有り

瀬部昇,北森俊行

計測自動制御学会論文集 31 ( 6 ) 743 - 750 1995年06月

分散制御からみた古典制御と現代制御の掛橋

瀬部昇,北森俊行

計測と制御 ( 未設定 ) 34 ( 6 ) 481 - 488 1995年06月

既約分解表現に基づく分散型安定化補償器の設計査読有り

瀬部昇,北森俊行

計測自動制御学会論文集 30 ( 12 ) 1474 - 1483 1994年12月

Controllability of Autonomous Decentralized Systems 査読有り

Reiko Tanaka,Seiichi Shin and Noboru Sebe

ETFA '94 265 - 272 1994年11月

On a Design of Multi-compensator Configuration 査読有り

Noboru Sebe and Toshiyuki Kitamori

Proceedings of the 1st ASCC ( 3 ) 109 - 112 1994年07月

Reliable Stabilization Based on a Multi-Compensator Configuration 査読有り

Noboru Sebe and Toshiyuki Kitamori

Preprints of the 12th IFAC World Congress ( 4 ) 5 - 8 1993年07月

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