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Switched Output Feedback Control for Networked Systems

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Abstract:
In this presentation a switched output feedback control scheme for networked systems will be presented. The control scheme is applied on client-server architectures where the feedback control loop is closed over a general purpose wireless communication channel between the plant (server) and the controller (client). The inserted delays from the communication network in general are time-varying and degrade the system’s dynamic performance, while forcing it to instabilities. To deal with these changes a Linear Quadratic Regulator (LQR) - output feedback scheme is introduced, whose parameters are adjusted accordingly to the variation of the measured round trip latency times. The weights of the LQR controllers are subsequently tuned using the theory of the Linear Matrix Inequalities (LMIs) to ensure a prescribed stability margin despite the variable latency time. The overall scheme resembles a gain scheduler controller with the latency times playing the role of the scheduling parameter. The proposed control scheme is applied in experimental and simulation studies on a networked controlled system over different communication channels such as: a) the GPRS, b) the IEEE 802.11b and c) the IEEE 802.15.4. The underlying mechanisms that generate the time varying latency times at each case will also be presented and analyzed prior to the control scheme development.

http://www.lar.ee.upatras.gr/gnikolakopoulos/
Type of Seminar:
Public Seminar
Speaker:
Dr. George Nikolakopoulos
Electrical and Computer Engineering Dept, University of Patras, Rio Achaias, 26500, Greece
Date/Time:
Oct 26, 2006   10:45
Location:

ETH Zurich, Physikstr. 3, ETL K 25
Contact Person:

Prof. J. Lygeros
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Biographical Sketch:
Dr. George Nikolakopoulos was born in Athens, Greece in 1976. He received his Diploma and Ph.D. from the Department of Electrical and Computer Engineering in 200 and 2006 respectively. So far, his research interests encompass fields, such as Sensor Networks, Networked Controlled Systems, Adaptive Robust Control, System Identification, Robotic Systems & Signal Processing. In the past he has worked as researcher in several R&D projects, such as “WINGEM” and “OPTINAV” (funded by the European Union), “PENED-'99” (funded by the Greek General Secretariat of Research), RUNES (IST), HYCON (NOE) etc. In the year 2003, he has received the IST Prize Award, for the best paper that promotes the scopes of the European IST. His practical and scientific work includes more than 40 published Journals and Conferences in the fields of his interests. Dr. Nikolakopoulos is a member of the Technical Chamber of Greece & the Institute of Electrical & Electronic Engineers IEEE.