Seminars and Events at automatic control
All seminars are held at the Department of Automatic Control, in the seminar room M 3170-73 on the third floor in the M-building, unless stated otherwise.
Seminar by Axel Ringh: Gain- and phase-type multipliers for phase- and gain-type robustness
Seminarium
From:
2025-03-20 15:15
to
15:55
Place: Seminar Room M 3170-73 at Dept. of Automatic Control, LTH
Contact: anders [dot] rantzer [at] control [dot] lth [dot] se
Date & Time: March 20, 15:15-15:55
Location: Seminar Room M 3170-73 at Dept. of Automatic Control, LTH
Speaker: Axel Ringh
Title: Gain- and phase-type multipliers for phase- and gain-type robustness
Abstract: A fundamental problem in control theory is robust stability analysis, that is, the problem of determining if a feedback interconnection between a nominal system and a set of uncertainties is stable for all uncertainties in the set. Under mild conditions, the solvability of a set of linear matrix inequalities (LMIs) is a both necessary and sufficient condition for robust stability, and the search for such solutions, known as multipliers, for guaranteeing robust stability of a feedback interconnection is a common theme in the control theory literature. In this talk, I will present new results on that robustness to certain forms of structured uncertainties is equivalent with the existence of certain forms of structured multipliers. In particular, with appropriate notions of gain and phase, we show that there always exists a gain-type multiplier for guaranteeing phase-type robustness, and there always exists a phase-type multiplier for guaranteeing gain-type robustness.
Biography: Axel Ringh received the M.Sc. degree in Engineering Physics in 2014, and the Ph.D. degree in Applied and Computational Mathematics in 2019, both from KTH Royal Institute of Technology. From 2019 to 2021 he was a postdoctoral researcher with the Department of Electronic and Computer Engineering, the Hong Kong University of Science and Technology, and since 2021 he is an assistant professor at the Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg. His research interests are within field of applied mathematics, more specifically in the intersection of areas such as optimization, systems theory, signal processing, inverse problems, and machine learning.