We study tracking controller design problems for key models of planar vertical takeoff and landing (PVTOL) aircraft and unmanned air vehicles (UAVs). The novelty of our PVTOL work is the global boundedness of our controllers in the decoupled coordinates, the positive uniform lower bound on the thrust controller, the applicability of our work to cases where the velocity measurements may not be a...

This paper is concerned with the problem of observer control of a class of time-varying delay systems with delayed measurements. By using information on delay derivative, improved asymptotic stability conditions for time-delay systems are presented. Unlike previous methods, upper bound of delay derivative is taken into consideration, even if this upper bound is larger than or equal to 1. We dev...

In this work we discuss nonuniform and semi-uniform input-to-state stability (iss) properties for time-varying systems. Treating the iss properties for a time varying system as properties related to output stability for a time invariant auxiliary system, we provide several characterizations in terms of Lyapunov functions and the asymptotic gains; as well as a small gain theorem, for the time va...

in this article, we survey the asymptotic stability analysis of fractional differential systems with the prabhakar fractional derivatives. we present the stability regions for these types of fractional differential systems. a brief comparison with the stability aspects of fractional differential systems in the sense of riemann-liouville fractional derivatives is also given.

Recently it has been shown that the conventional notions of stability in the sense of Lyapunov and asymptotic stability can be used to characterize the stability properties of a class of “logical” discrete event systems (DES). Moreover, it has been shown that stability analysis via the choice of appropriate Lyapunov functions can be used for DES and can be applied to several DES applications in...

A dynamical system is called positive if any solution of the system starting from nonnegative states maintains nonnegative states forever. In many applications where variables represent nonnegative quantities we often encounter positive dynamical systems as mathematical models see 1, 2 , and many researches for positive systems have been done actively; for recent developments see, for example, ...

The paper emphasizes the property of stability for skew-evolution semiflows on Banach spaces, defined by means of evolution semiflows and evolution cocycles and which generalize the concept introduced by us in [10]. There are presented several general characterizations of this asymptotic property out of which can be deduced well known results of the stability theory. A unified treatment in the ...

Motivated by questions in biology, we investigate the stability of equilibria of the dynamical system x = P (t)∇f(x) which arise as critical points of f , under the assumption that P (t) is positive semi-definite. It is shown that the condition ∫ ∞ λ1(P (t)) dt = ∞, where λ1(P (t)) is the smallest eigenvalue of P (t), plays a key role in guaranteeing uniform asymptotic stability and in providin...

Asymptotic output stability (AOS) is an interesting property when addressing control applications in which not all state variables are requested to converge the origin. AOS often established by invoking classical tools such as Barbashin–Krasovskii–LaSalle’s invariance principle or Barb?lat’s lemma. Nevertheless, none of these allow predict whether convergence uniform on bounded sets initial con...