2024 |
Daniel Liberzon / Hyungbo Shim Stability of Nonlinear Systems with Slow and Fast Time Variation and Switching: The Common Equilibrium Case Proceedings Article In: 2024 IEEE 63rd Conference on Decision and Control (CDC), IEEE, Milan, Italy, 2024. Abstract | Links | BibTeX | Tags: Non-Linear Systems, Switched system @inproceedings{nokey,In this paper we consider a class of nonlinear systems with two kinds of inputs: one is slowly-varying, the other is fast-varying and periodic, and both are only piecewise continuous. Under the assumption that the origin is a common equilibrium for all values of the input signals, we provide sufficient conditions under which this equilibrium is semi-globally exponentially stable. Our approach is based on considering the (partial) average system which averages out the fast variation but retains the slow variation, and which can be used to approximate the original system in a certain sense. The stability conditions involve the existence of a suitable Lyapunov function for this average system, along with a bound on the total variation of the slowly-varying input. |
Andrew Teel / Aneel Tanwani / Hyungbo Shim Stability Analysis of Nonlinear Systems Over Switching Networks Using Singularly Perturbed Hybrid Systems Framework Proceedings Article In: 26th International Symposium on Mathematical Theory of Networks and Systems, MTNS, cambridge,UK, 2024. Abstract | Links | BibTeX | Tags: Hybrid system, Multi-agent system, Non-Linear Systems @inproceedings{nokey,To analyze the stability of a network of agents described by nonlinear oscillators which only exchange information about their position with some of its neighbors from time to time, we consider a theoretical framework of singularly perturbed hybrid systems. We describe such systems as an interconnection of two hybrid subsystems, a timer which triggers the jumps, and some discrete variables to determine the index of the jump maps. The flow equations of these variables are singularly perturbed differential equations, and in particular, smaller value of the singular perturbation parameter leads to increase in the frequency of the jump instants. For the limiting value of this parameter, we consider a decomposition which comprises a quasi-steady-state system modeled by a differential equation without any jumps, and a boundary-layer system described by purely discrete dynamics. Under appropriate stability assumptions on the quasi-steady-state system and the boundary-layer system, we derive results showing practical stability of a compact attractor when the information exchange between the agents occurs frequently often. |
2004 |
Juhoon Back / Jin Heon Seo Immersion of non-linear systems into linear systems up to output injection: characteristic equation approach Journal Article In: International Journal of Control, vol. 77, no. 8, pp. 723-734, 2004, ISSN: 0020-7179. Abstract | Links | BibTeX | Tags: Non-Linear Systems @article{BackSeo04,There exists a class of non-linear systems which cannot be transformed into non-linear observer form via diffeomorphism, but can be immersed into higher dimensional non-linear observer form. This paper investigates when n dimensional non-linear systems can be immersed into (n + m)-dimensional non-linear systems in non-linear observer form, and provides a necessary and sufficient condition. We also present an algorithm to check the immersibility. In general, at the first step of the algorithm, one should solve a differential equation with m + 1 unknowns rather than solving one with n + m unknowns simultaneously. When a solution to the differential equation can be obtained, the immersibility can be checked by a recursive algorithm. Moreover, when 2m ≤ n, a straightforward algorithm is provided to check the immersibility. |
2000 |
Nam Hoon Jo / Jin Heon Seo Local separation principle for non-linear systems Journal Article In: International Journal of Control, vol. 73, no. 4, pp. 292-302, 2000, ISSN: 0020-7179. Abstract | Links | BibTeX | Tags: Non-Linear Systems @article{JoSeo00c,In this paper, we consider the problem of locally stabilizing non-linear systems by output feedback control. To be precise, the separation principle for non-linear systems are studied, which allows the design of the control law and the observer to be carried out independently. While the previous results assumed the existence of Lyapunov function for the observation error, we assume the existence of a state observer which asymptotically estimates the true state. As a matter of fact, it turns out that the latter condition is necessary for the former condition, but the converse is not true. The separation principle with the reduced order observer is also presented. Under the assumption that a non-linear system has asymptotically stable zero dynamics and is locally detectable, it is shown that the asymptotic output tracking by output feedback control can be achieved. |
List of English Publication
2024 |
Stability of Nonlinear Systems with Slow and Fast Time Variation and Switching: The Common Equilibrium Case Proceedings Article In: 2024 IEEE 63rd Conference on Decision and Control (CDC), IEEE, Milan, Italy, 2024. |
Stability Analysis of Nonlinear Systems Over Switching Networks Using Singularly Perturbed Hybrid Systems Framework Proceedings Article In: 26th International Symposium on Mathematical Theory of Networks and Systems, MTNS, cambridge,UK, 2024. |
2004 |
Immersion of non-linear systems into linear systems up to output injection: characteristic equation approach Journal Article In: International Journal of Control, vol. 77, no. 8, pp. 723-734, 2004, ISSN: 0020-7179. |
2000 |
Local separation principle for non-linear systems Journal Article In: International Journal of Control, vol. 73, no. 4, pp. 292-302, 2000, ISSN: 0020-7179. |