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22 results on '"Mele, Adriano"'

1. Assessing the Finite-Time Stability of Nonlinear Systems by means of Physics-Informed Neural Networks

Author

Mele, Adriano and Pironti, Alfredo

Subjects
Mathematics - Optimization and Control, Electrical Engineering and Systems Science - Systems and Control
Abstract

In this paper, the problem of assessing the Finite-Time Stability (FTS) property for general nonlinear systems is considered. First, some necessary and sufficient conditions that guarantee the FTS of general nonlinear systems are provided; such conditions are expressed in terms of the existence of a suitable Lyapunov-like function. Connections of the main theoretical result of given in this article with the typical conditions based on Linear Matrix Inequalities (LMI) that are used for Linear Time-Varying (LTV) systems are discussed. An extension to the case of discrete time systems is also provided. Then, we propose a method to verify the obtained conditions for a very broad class of nonlinear systems. The proposed technique leverages the capability of neural networks to serve as universal function approximators to obtain the Lyapunov-like function. The network training data are generated by enforcing the conditions defining such function in a (large) set of collocation points, as in the case of Physics-Informed Neural Networks. To illustrate the effectiveness of the proposed approach, some numerical examples are proposed and discussed. The technique proposed in this paper allows to obtain the required Lyapunov-like function in closed form. This has the twofold advantage of a) providing a practical way to verify the considered FTS property for a very general class of systems, with an unprecedented flexibility in the FTS context, and b) paving the way to control applications based on Lyapunov methods in the framework of Finite-Time Stability and Control., Comment: 11 pages, journal paper preprint

Published
2023

2. Vertical stabilization of tokamak plasmas via Extremum Seeking

Author

De Tommasi, Gianmaria, di Grazia, Luigi Emanuel, Dubbioso, Sara, Mattei, Massimiliano, Mele, Adriano, and Pironti, Alfredo

Subjects
Physics - Plasma Physics, 93D15
Abstract

In this paper we propose a vertical stabilization~(VS) control system for tokamak plasmas based on the extremum seeking (ES) algorithm. The gist of the proposed strategy is to inject an oscillating term in the control action and exploit a modified ES algorithm in order to bring to zero the average motion of the plasma along the unstable mode. In this way, the stabilization of the unstable vertical dynamic of the plasma is achieved. The approach is validated by means of both linear and nonlinear simulations of the overall~ITER tokamak magnetic control system, with the aim of demonstrating robust operation throughout the flat-top phase of a discharge and the capability of reacting to a variety of disturbances., Comment: 17 pages, 14 figures

Published
2022

5. Finite-Time stabilization of linear systems with unknown control direction via Extremum Seeking

Author

Mele, Adriano, De Tommasi, Gianmaria, and Pironti, Alfredo

Subjects
Mathematics - Optimization and Control
Abstract

In this paper the finite-time stabilization problem is solved for a linear time-varying system with unknown control direction by exploiting a modified version of the classical extremum seeking algorithm. We propose to use a suitable oscillatory input to modify the system dynamics, at least in an average sense, so as to satisfy a Differential Linear Matrix Inequality (DLMI) condition which in turns guarantees that the system's state remains inside a prescribed time varying hyper-ellipsoid in the state space. The finite-time stability (FTS) of the averaged dynamics implies the FTS of the original system, as the distance between the original and the averaged dynamics can be made arbitrarily small by choosing a sufficiently high value of the dithering frequency used by the extremum seeking algorithm. An estimate of the necessary minimum dithering/mixing frequency is provided, and the effectiveness of the proposed finite-time stabilization approach is analysed by means of numerical examples.

Published
2021

16. A flexible architecture for plasma magnetic control in tokamak reactors

Author

Mele, Adriano

Subjects
ING-IND/18 Fisica dei reattori nucleari, Tokamak, ING-IND/31 Elettrotecnica, Settore ING-IND/18 - Fisica dei Reattori Nucleari, Plasma, Magnetic Control, EAST, JT-60SA, Shape Control, Settore ING-IND/31 - Elettrotecnica, Settore ING-INF/04 - Automatica, ING-INF/04 Automatica, ING-IND/19 Impianti nucleari, Settore ING-IND/19 - Impianti Nucleari
Abstract

Plasma magnetic control is one of the core engineering issues to be tackled in a fusion device. Over the last years, model based approaches have been proposed to face this issue, proving their effectiveness and allowing to reduce the time span needed for control testing and validation. The first part of this work is intended to give an overview of the subject, from the historical milestones to the underlying physics; the most common techniques for tokamak plasmas electromagnetic modeling and control are also introduced and discussed. After this introduction, a general architecture for plasma magnetic control in tokamaks is proposed. Finally, the proposed solution is applied to the Experimental Advanced Superconducting Tokamak (EAST) tokamak, where a new plasma magnetic control architecture was developed and implemented during the 2016-2018 experimental campaigns, and to the Japan Torus-60 Super Advanced (JT-60SA) device, which is currently under construction in Japan.

Published
2019

17. Physics and operation oriented activities in preparation of the JT-60SA tokamak exploitation

Author

Giruzzi, Gerardo, Joffrin, E., Garcia, J., Douai, D., Artaud, J. F., Pégourié, B., Maget, P., Kamada, Y., Yoshida, M., Ide, S., Hayashi, N., Matsunaga, G., Nakano, T., Shinohara, K., Sakurai, S., Suzuki, T., Urano, H., Enoeda, M., Kubo, Hiroshi, Kamiya, K., Takechi, M., Miyata, Y., Isayama, A., Kobayashi, T., Moriyama, S., Shimizu, K., Hoshino, K., Kawashima, H., Bierwage, A., Mcdonald, D., Sozzi, C., Figini, L., Nowak, S., Moro, A., Platania, P., Ricci, Daniele, Granucci, G., Bolzonella, Tommaso, Bettini, P., Innocente, P., Terranova, David, Pigatto, Leonardo, Villone, F., Pironti, Alfredo, Mastrostefano, S., De Tommasi, G., Mattei, M., Mele, Adriano, Orsitto, F., Dunai, D., Szepesi, T., Barbato, E., Vitale, V., Romanelli, M., Garzotti, L., Boboc, A., Saarelma, S., Wischmeier, M., Lauber, P., Lang, P., Neu, R., Day, C., Gleason Gonzalez, C., Scannapiego, M., Zagorski, R., Galazaka, K., Stepniewski, W., Cruz, N., De La Luna, E., Farcia Munoz, M., Vega, J., Clement Lorenzo, S., Sartori, F., Coda, S., Goodman, T., and Soare, S.

Published
2016

18. Stabilizing elongated plasmas using extremum seeking: the ITER tokamak case study

Author

Alfredo Pironti, Sara Dubbioso, A. Mele, Gianmaria De Tommasi, De Tommasi, Gianmaria, Dubbioso, Sara, Mele, Adriano, and Pironti, Alfredo

Subjects
Physics, Tokamak, Vertical stabilization, plasma vertical stabilization, plasma magnetic control, tokamak, model-free control, extremum seeking, Filtering theory, Mode (statistics), Iter tokamak, Plasma, law.invention, Physics::Plasma Physics, law, Robustness (computer science), Control theory, Control system
Abstract

In this paper we propose a model-free approach to stabilize vertical unstable plasmas in tokamak devices. The approach relies on the extremum seeking algorithm and on averaging theory to bring to zero the motion of the plasma along the unstable mode, hence achieving the stabilization of its vertical dynamic. The effectiveness of the proposed approach is shown by means of simulations. To this aim, the proposed model-free vertical stabilization system is included in the magnetic control system of the ITER tokamak to consider relevant operational scenarios.

Published
2021

19. Control-oriented tools for the design and validation of the JT-60SA magnetic control system

Author

G. De Tommasi, Nuno Cruz, Alfredo Pironti, A. Mele, Y. Miyata, T. Suzuki, Massimiliano Mattei, Cruz, N., DE TOMMASI, Gianmaria, Mattei, M., Mele, Adriano, Miyata, Y., Pironti, Alfredo, Suzuki, T., De Tommasi, G., Mattei, Massimiliano, Mele, A., and Pironti, A.

Subjects
Engineering, Tokamak, Control (management), JT-60SA, 01 natural sciences, 010305 fluids & plasmas, law.invention, Set (abstract data type), Control oriented, law, 0103 physical sciences, media_common.cataloged_instance, Electrical and Electronic Engineering, European union, Architecture, 010306 general physics, media_common, Control in fusion device, business.industry, Applied Mathematics, Control in fusion devices, Plasma magnetic control in tokamak, Control and Systems Engineering, Project team, Computer Science Applications, Control system, Systems engineering, business
Abstract

The construction and operation of the JT-60SA tokamak is the main project currently carried out jointly by Japan and the European Union under the Broader Approach agreement. Within the Integrated Project Team, Japanese and European scientists are developing and testing a number of tools to support preliminary studies and future operations of JT-60SA. Within this collaborative framework, European scientists are using a set of assessed modeling tools to design and validate possible solutions for the plasma magnetic control system of JT-60SA. This paper introduces these tools and describes a possible control architecture to be used on the JT-60SA tokamak. The effectiveness of the proposed architecture is shown by means of numerical simulations.

Published
2017

20. Robust Plasma Vertical Stabilization in Tokamak Devices via Multi-objective Optimization

Author

Gianmaria De Tommasi, Alfredo Pironti, A. Mele, Antonio Sforza, Claudio Sterle, De Tommasi, Gianmaria, Mele, Adriano, and Pironti, Alfredo

Subjects
Optimization problem, Tokamak, Vertical stabilization, Computer science, Control in nuclear fusion devices, Robust control, Plasma, 01 natural sciences, Multi-objective optimization, 010305 fluids & plasmas, law.invention, Robust design, Control theory, Mathematics (all), Physics::Plasma Physics, law, 0103 physical sciences, 010306 general physics
Abstract

In this paper we present a robust design procedure for plasma vertical stabilization systems in tokamak fusion devices. The proposed approach is based on the solution of a multi-objective optimization problem, whose solution is aimed at obtaining the desired stability margins under different plasma operative scenarios. The effectiveness of the proposed approach is shown by applying it to the ITER-like vertical stabilization system recently tested on the EAST tokamak.

Published
2017

21. Physics and operation oriented activities in preparation of the JT-60SA tokamak exploitation

Author

H. Sasao, T. Bolzonella, D. C. McDonald, Lorenzo Figini, Peter Lang, A. Boboc, G. Pautasso, R. Neu, V. Vitale, J.F. Artaud, G. De Tommasi, C. Gil, A. Kojima, Akihiko Isayama, S. Saarelma, Patrick Maget, Yasunori Kawano, Y. Miyata, L. Pigatto, Carlo Sozzi, Timothy Goodman, Paolo Bettini, David Terranova, M. Romanelli, B. Pégourié, E. de la Luna, Manabu Takechi, K. Galazka, Maiko Yoshida, F. Orsitto, A. Mele, J. Garcia, J. Galdon, Ryota Imazawa, Paola Platania, S. Clement-Lorenzo, Hajime Urano, Go Matsunaga, W. Stepniewski, M. Enoeda, Hisato Kawashima, L. Garzotti, Masakatsu Fukumoto, M. Toma, Daniela Farina, Kazuo Hoshino, S. Soare, M. Scannapiego, Yutaka Kamada, S. Sakurai, Paolo Innocente, K. Shinohara, M. Dibon, H. Kubo, R. Zagórski, S. Mastrostefano, O. Asztalos, D. Ricci, K. Itami, Stefano Coda, T. Kobayashi, Gergö Pokol, Daniel Dunai, Kenji Tanaka, A. Moro, Giuseppe Marchiori, C. Gleason-González, S. Nowak, Tamás Szepesi, Chr. Day, N. Hayashi, Filippo Sartori, Ph. Lauber, Jesús Vega, D. Douai, T. Nakano, K. Shimizu, E. Barbato, Nuno Cruz, G. Giruzzi, Shunsuke Ide, M. Wischmeier, Alfredo Pironti, Fabio Villone, Shinichi Moriyama, Kensaku Kamiya, M. Garcia-Munoz, Massimiliano Mattei, E. Joffrin, J. Shiraishi, T. Suzuki, Gustavo Granucci, T. Wakatsuki, Andreas Bierwage, Y. Suzuki, Giruzzi, G., Yoshida, M., Artaud, J. F., Asztalos, Ö., Barbato, E., Bettini, P., Bierwage, A., Boboc, A., Bolzonella, T., Clement Lorenzo, S., Coda, S., Cruz, N., Day, C. h. r., DE TOMMASI, Gianmaria, Dibon, M., Douai, D., Dunai, D., Enoeda, M., Farina, D., Figini, L., Fukumoto, M., Galazka, K., Galdon, J., Garcia, J., Garcia Muñoz, M., Garzotti, L., Gil, C., Gleason Gonzalez, C., Goodman, T., Granucci, G., Hayashi, N., Hoshino, K., Ide, S., Imazawa, R., Innocente, P., Isayama, A., Itami, K., Joffrin, E., Kamada, Y., Kamiya, K., Kawano, Y., Kawashima, H., Kobayashi, T., Kojima, A., Kubo, H., Lang, P., Lauber, P. h., de la Luna, E., Maget, P., Marchiori, G., Mastrostefano, S., Matsunaga, G., Mattei, M., Mcdonald, D. C., Mele, Adriano, Miyata, Y., Moriyama, S., Moro, A., Nakano, T., Neu, R., Nowak, S., Orsitto, F. P., Pautasso, G., Pégourié, B., Pigatto, L., Pironti, Alfredo, Platania, P., Pokol, G. I., Ricci, D., Romanelli, M., Saarelma, S., Sakurai, S., Sartori, F., Sasao, H., Scannapiego, M., Shimizu, K., Shinohara, K., Shiraishi, J., Soare, S., Sozzi, C., Stępniewski, W., Suzuki, T., Suzuki, Y., Szepesi, T., Takechi, M., Tanaka, K., Terranova, D., Toma, M., Urano, H., Vega, J., Villone, F., Vitale, V., Wakatsuki, T., Wischmeier, M., Zagórski, R., Asztalos, O., Clement-Lorenzo, S., Day, Chr, De Tommasi, G., Garcia-Munoz, M., Gleason-Gonzalez, C., De La Luna, E., Mele, A., Pã©gouriã©, B., Pironti, A., Stè©pniewski, W., Zagã³rski, R., Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, and Universidad de Sevilla. RNM138: Física Nuclear Aplicada

Subjects
Nuclear and High Energy Physics, Tokamak, diagnostic, JT-60SA, 01 natural sciences, Modelling, 010305 fluids & plasmas, law.invention, modelling, Research plan, law, 0103 physical sciences, diagnostics, ddc:530, 010306 general physics, Diagnostics, tokamak, Operation, Nuclear and High Energy Physic, Physics, modeling, operation, Condensed Matter Physics, Chemical physics, Systems engineering
Abstract

The JT-60SA tokamak, being built under the Broader Approach agreement jointly by Europe and Japan, is due to start operation in 2020 and is expected to give substantial contributions to both ITER and DEMO scenario optimisation. A broad set of preparation activities for an efficient start of the experiments on JT-60SA is being carried out, involving elaboration of the Research Plan, advanced modelling in various domains, feasibility and conception studies of diagnostics and other sub-systems in connection with the priorities of the scientific programme, development and validation of operation tools. The logic and coherence of this approach, as well as the most significant results of the main activities undertaken are presented and summarised. EURATOM 633053

Published
2017
Full Text
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22. On plasma vertical stabilization at EAST tokamak

Author

Zhengping Luo, B.J. Xiao, A. Mele, Alfredo Pironti, G. De Tommasi, DE TOMMASI, Gianmaria, Mele, Adriano, Luo, Z. P., Pironti, Alfredo, and Xiao, B. J.

Subjects
Coupling, 0209 industrial biotechnology, Engineering, Tokamak, business.industry, Magnetic separation, 02 engineering and technology, Plasma, Decoupling (cosmology), 01 natural sciences, 010305 fluids & plasmas, law.invention, 020901 industrial engineering & automation, Control theory, law, Control system, 0103 physical sciences, Vertical direction, business
Abstract

In this paper we discuss the problem of plasma vertical stabilization at the EAST tokamak. By exploiting a plasma/circuit linearized model, we show that the plant cannot be strongly stabilized by using the in-vessel coils and a single-input-single-output controller that feeds back only the plasma vertical speed (z)over dot(p) (i.e. without integral action on (z)over dot(p)). Moreover, a stable multi-input-single-output controller that stabilizes the plant without the need of feeding back the plasma vertical position is presented. The proposed solution permits to achieve stabilization of the EAST plant without coupling the vertical stabilization system with the plasma shape controller. Such decoupling is a key requirement to enable advanced design approaches for plasma shape controller.

Published
2017
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