Lyapunov stability analysis of a string equation coupled with an ordinary differential system

Matrix Lyapunov inequalities for ordinary and elliptic partial differential equations

This paper is devoted to the study of $L_p$ Lyapunov-type inequalities for linear systems of equations with Neumann boundary conditions and for any constant $p \geq 1$. We consider ordinary and elliptic problems. The results obtained in the linear case are combined with Schauder fixed point theorem to provide new results about the existence and uniqueness of solutions for resonant nonlinear problems. The proof uses in a fundamental way the nontrivial relation between the best Lyapunov constants and the minimum value of some especial minimization problems.

Forwarding-Lyapunov design for the stabilization of coupled ODEs and exponentially stable PDEs

This paper is about the stabilization of a cascade system composed by an infinite-dimensional system, that we suppose to be exponentially stable, and an ordinary differential equation (ODE), that we suppose to be marginally stable. The system is controlled through the infinite-dimensional system. Such a structure is particularly useful when applying the internal model approach on infinite-dimensional systems. Our strategy relies on the forwarding method, which uses a Lyapunov functional and a Sylvester equation to build a feedback-law. Under some classical assumptions in the output regulation …

An applied mathematical excursion through Lyapunov inequalities, classical analysis and differential equations

Several different problems make the study of the so called Lyapunov type inequalities of great interest, both in pure and applied mathematics. Although the original historical motivation was the study of the stability properties of the Hill equation (which applies to many problems in physics and engineering), other questions that arise in systems at resonance, crystallography, isoperimetric problems, Rayleigh type quotients, etc. lead to the study of $L_p$ Lyapunov inequalities ($1\leq p\leq \infty$) for differential equations. In this work we review some recent results on these kinds of quest…

具有Kelvin-Voigt阻尼的非线性轴向运动弦的稳定性

Stability of a Nonlinear Axially Moving String With the Kelvin-Voigt Damping

本文研究了具有Kelvin-Voigt阻尼的轴向运动非线性弦线。证明了弦是稳定的，即，当弦的轴向速度小于某一临界值时，其横向位移收敛为零。证明是通过证明对应于弦的李雅普诺夫函数指数衰减到零来建立的。它还表明，字符串位移有界时，有界分布的力施加到它的横向。此外，几个开放的问题，关于稳定性和稳定的Kelvin-Voigt阻尼的字符串的陈述。

Estimates for principal Lyapunov exponents: A survey

This is a survey of known results on estimating the principal Lyapunov exponent of a time-dependent linear differential equation possessing some monotonicity properties. Equations considered are mainly strongly cooperative systems of ordinary differential equations and parabolic partial differential equations of second order. The estimates are given either in terms of the principal (dominant) eigenvalue of some derived time-independent equation or in terms of the parameters of the equation itself. Extensions to other differential equations are considered. Possible directions of further researc…

Exponential Lyapunov Stability Analysis of a Drilling Mechanism

This article deals with the stability analysis of a drilling system which is modelled as a coupled ordinary differential equation / string equation. The string is damped at the two boundaries but leading to a stable open-loop system. The aim is to derive a linear matrix inequality ensuring the exponential stability with a guaranteed decay-rate of this interconnected system. A strictly proper dynamic controller based on boundary measurements is proposed to accelerate the system dynamics and its effects are investigated through the stability theorem and simulations. It results in an efficient fi…