3 research outputs found
Sub-homogeneous positive monotone systems are insensitive to heterogeneous time-varying delays
We show that a sub-homogeneous positive monotone system with bounded
heterogeneous time-varying delays is globally asymptotically stable if and only
if the corresponding delay-free system is globally asymptotically stable. The
proof is based on an extension of a delay-independent stability result for
monotone systems under constant delays by Smith to systems with bounded
heterogeneous time-varying delays. Under the additional assumption of
positivity and sub-homogeneous vector fields, we establish the aforementioned
delay insensitivity property and derive a novel test for global asymptotic
stability. If the system has a unique equilibrium point in the positive
orthant, we prove that our stability test is necessary and sufficient.
Specialized to positive linear systems, our results extend and sharpen existing
results from the literature.Comment: Submitted to the 21st International Symposium on Mathematical Theory
of Networks and Systems (MTNS), 201
Asymptotic Stability and Decay Rates of Homogeneous Positive Systems With Bounded and Unbounded Delays
There are several results on the stability of nonlinear positive systems in
the presence of time delays. However, most of them assume that the delays are
constant. This paper considers time-varying, possibly unbounded, delays and
establishes asymptotic stability and bounds the decay rate of a significant
class of nonlinear positive systems which includes positive linear systems as a
special case. Specifically, we present a necessary and sufficient condition for
delay-independent stability of continuous-time positive systems whose vector
fields are cooperative and homogeneous. We show that global asymptotic
stability of such systems is independent of the magnitude and variation of the
time delays. For various classes of time delays, we are able to derive explicit
expressions that quantify the decay rates of positive systems. We also provide
the corresponding counterparts for discrete-time positive systems whose vector
fields are non-decreasing and homogeneous.Comment: SIAM Journal on Control and Optimizatio
Stability Analysis of Monotone Systems via Max-separable Lyapunov Functions
We analyze stability properties of monotone nonlinear systems via
max-separable Lyapunov functions, motivated by the following observations:
first, recent results have shown that asymptotic stability of a monotone
nonlinear system implies the existence of a max-separable Lyapunov function on
a compact set; second, for monotone linear systems, asymptotic stability
implies the stronger properties of D-stability and insensitivity to
time-delays. This paper establishes that for monotone nonlinear systems,
equivalence holds between asymptotic stability, the existence of a
max-separable Lyapunov function, D-stability, and insensitivity to bounded and
unbounded time-varying delays. In particular, a new and general notion of
D-stability for monotone nonlinear systems is discussed and a set of necessary
and sufficient conditions for delay-independent stability are derived. Examples
show how the results extend the state-of-the-art