868 research outputs found
A graph theoretic approach to input-to-state stability of switched systems
This article deals with input-to-state stability (ISS) of discrete-time
switched systems. Given a family of nonlinear systems with exogenous inputs, we
present a class of switching signals under which the resulting switched system
is ISS. We allow non-ISS systems in the family and our analysis involves
graph-theoretic arguments. A weighted digraph is associated to the switched
system, and a switching signal is expressed as an infinite walk on this
digraph, both in a natural way. Our class of stabilizing switching signals
(infinite walks) is periodic in nature and affords simple algorithmic
construction.Comment: 14 pages, 1 figur
Stabilizing switching signals: a transition from point-wise to asymptotic conditions
Characterization of classes of switching signals that ensure stability of
switched systems occupies a significant portion of the switched systems
literature. This article collects a multitude of stabilizing switching signals
under an umbrella framework. We achieve this in two steps: Firstly, given a
family of systems, possibly containing unstable dynamics, we propose a new and
general class of stabilizing switching signals. Secondly, we demonstrate that
prior results based on both point-wise and asymptotic characterizations follow
our result. This is the first attempt in the switched systems literature where
these switching signals are unified under one banner.Comment: 7 page
Formal synthesis of stabilizing controllers for periodically controlled linear switched systems
In this paper, we address the problem of synthesizing periodic switching controllers for stabilizing a family of linear systems. Our broad approach consists of constructing a finite game graph based on the family of linear systems such that every winning strategy on the game graph corresponds to a stabilizing switching controller for the family of linear systems. The construction of a (finite) game graph, the synthesis of a winning strategy and the extraction of a stabilizing controller are all computationally feasible. We illustrate our method on an example
Practical dwell times for switched system stability with smart grid application
Switched systems are encountered throughout many engineering disciplines, but confirming their stability is a challenging task. Even if each subsystem is asymptotically stable, certain switching sequences may exist that drive the overall system states into unacceptable regions. This thesis contains a process that grants stability under switching to switched systems with multiple operating points. The method linearizes a switched system about its distinct operating points, and employs multiple Lyapunov functions to produce modal dwell times that yield stability. This approach prioritizes practicality and is designed to be useful for large systems with many states and subsystems due to its ease of algorithmic implementation. Power applications are particularly targeted, and several examples are provided in the included papers that apply the technique to boost converters, electric machines, and smart grid architectures --Abstract, page iv
Converse Lyapunov theorems for discrete-time linear switching systems with regular switching sequences
We present a stability analysis framework for the general class of
discrete-time linear switching systems for which the switching sequences belong
to a regular language. They admit arbitrary switching systems as special cases.
Using recent results of X. Dai on the asymptotic growth rate of such systems,
we introduce the concept of multinorm as an algebraic tool for stability
analysis.
We conjugate this tool with two families of multiple quadratic Lyapunov
functions, parameterized by an integer T >= 1, and obtain converse Lyapunov
Theorems for each.
Lyapunov functions of the first family associate one quadratic form per state
of the automaton defining the switching sequences. They are made to decrease
after every T successive time steps. The second family is made of the
path-dependent Lyapunov functions of Lee and Dullerud. They are parameterized
by an amount of memory (T-1) >= 0.
Our converse Lyapunov theorems are finite. More precisely, we give sufficient
conditions on the asymptotic growth rate of a stable system under which one can
compute an integer parameter T >= 1 for which both types of Lyapunov functions
exist.
As a corollary of our results, we formulate an arbitrary accurate
approximation scheme for estimating the asymptotic growth rate of switching
systems with constrained switching sequences
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