Networked Control (5 CFU)

Automation and Control Engineering

 

Prof. Marcello Farina

Dipartimento di Elettronica, Informazione e Bioingegneria

Tel. 02 2399 3599

e. mail: marcello.farina@polimi.it

personal webpage: https://farina.faculty.polimi.it/

 

OBJECTIVES:

In the past decades a growing interest has been dedicated to networked systems and large-scale plants where parts of the system, e.g., sensors, actuators, are not collocated and are possibly distributed over a large geographic area. These classes of systems include, e.g., large chemical plants, power distribution networks, industrial factories, water distribution networks, and multiple agents cooperating with each other through suitable coordination schemes (e.g., unmanned aerial and ground vehicles and teams of robots).

The control of these systems may require communication through a shared transmission network and/or to resort to complex (e.g. hierarchical, distributed, or hierarchical) schemes.

However, one the one hand, communication through a shared transmission network involves a number of issues, e.g., bandwidth limitation, delays, packet dropouts, which can compromize the stability properties of the network. On the other hand, distributed and decentralized control structures entail structural constraints and limitations, and call for non-standard analysis and control design tools.

The course covers the necessary mathematical and technical tools for the analysis and the design of possibly complex control systems subject to communication and structural issues.

 

Lectures and exercise sessions will allow students to:

o  Understand the challenges, opportunities, and issues related to networked control systems.

o  Understand the possible sources of communication problems, including bandwidth limitations, delays, and packet dropouts.

o  Learn how to devise mathematical models where communication issues are formally described, and perform stability analysis of networked control systems, i.e., where communication takes place through a serial communication bus.

o  Understand the theoretical limitations (e.g., decentralized fixed modes) related to decentralized and distributed control structures, and learn how to design decentralized and distributed regulators with linear matrix inequalities.

TOPICS:

The course will cover the following topics:

o  Introduction on networked control systems, control architectures for large-scale and networked systems, and application areas. Issues and challenges of networked control systems.

o  Theoretical background. Basic and more advanced concepts in control theory (with focus on linear systems) will be recalled and covered, in order to provide consistent background to the students, e.g.

o  Stability of continuous-time and discrete-time systems;

o  Controllability and observability;

o  Basics on linear matrix inequalities in control systems analysis and design.

o  Decentralized and distributed control structures.

o  Definition of decentralized/sitributed fixed modes and stabilization with decentralized and distributed regulators.

o  Design of decentralized and distributed controllers using LMIs.

o  Control with communication issues.

o  Communication issues in networked control systems. Control networks, packet transmission, and transmission protocols.

o  Control with bandwidth limitations: minimum channel capacity requirements.

o  Network-induced delays and packet dropouts. Stability analysis in case of network-induced delays and packet dropouts.

Numerical lectures will consist of both numerical exercize and computer-based sessions. Concerning the latter, the described analysis and design methods will be implemented using dedicated computer tools and programs (e.g., MATLAB and YALMIP).

EVALUATION:

The Exam consists of two parts. Regarding the course Part II (Decentralized and distributed control structures) a project work will have to be completed and presented in an oral discussion. Regarding the course part III (Network control systems), a written test will be taken.

PREREQUISITES:

The students are required to have a background on (basics of) automatic control and systems theory, with specific focus on state-space (linear) models, both in continuous and in discrete time.

TEACHING MATERIAL:

o  The main course material consists of detailed slides and lecture notes, and of computer programs that will be made available on the BeeP/WeBeep Portal to registered users.

o  Supplementary suggested readings include

o  R. J. Baillieul, P. J. Antsaklis. Control and communication challenges in networked real-time systems. Proceedings of the IEEE, 95 (1), pp. 9-28.

o  J. R. Moyne and D. M. Tilbury. The emergence of industrial control networks for manufacturing control, diagnostics, and safety data. Proceedings of the IEEE, 95 (1), pp. 29-47.

o  R. J. Baillieul,. Feedback coding for information-based control: operating near the data-rate limit. Proceedings of the IEEE Conference on Decision and Control, 2002, pp. 3229-3236.

o  W. Zhang, M. S. Branicky, S. M. Phillips. Stability of networked control systems. IEEE Control Systems Magazine, 2001, pp. 84-99.

o  J. P. Hespanha, P. Naghshtabrizi, Y. Xu. A survey of recent results in networked control systems. Proceedings of the IEEE, 95 (1), pp. 138-162.

o  J. Lunze. Feedback Control of Large-Scale Systems. Prentice Hall International Series in Systems and Control Engineering, 1992.

o  A. Zecevic, D. D. Siljak. Control of complex systems. Structural constraints and uncertainty. Springer, 2010.

 

CALENDAR: