A Perturbed Iterative Method for a General Class of Variational Inequalities

The generalized Wiener-Hopf equation and the approximation methods are used to propose a perturbed iterative method to compute the solutions of a general class of nonlinear variational inequalities

Local nonsmooth Lyapunov pairs for first-order evolution differential inclusions

The general theory of Lyapunov's stability of first-order differential inclusions in Hilbert spaces has been studied by the authors in a previous work. This new contribution focuses on the natural case when the maximally monotone operator governing the given inclusion has a domain with nonempty interior. This setting permits to have nonincreasing Lyapunov functions on the whole trajectory of the solution to the given differential inclusion. It also allows some more explicit criteria for Lyapunov's pairs. Some consequences to the viability of closed sets are given, as well as some useful cases relying on the continuity or/and convexity of the involved functions. Our analysis makes use of standard tools from convex and variational analysis

Newton's Method for Solving Inclusions Using Set-Valued Approximations

International audienceResults on stability of both local and global metric regularity under set-valued perturbations are presented. As an application, we study (super)linear convergence of a Newton- type iterative process for solving generalized equations. We investigate several iterative schemes such as the inexact Newton’s method, the nonsmooth Newton’s method for semismooth functions, the inexact proximal point algorithm, etc. Moreover, we also cover a forward-backward splitting algorithm for finding a zero of the sum of two multivalued (not necessarily monotone) operators. Finally, a globalization of the Newton’s method is discussed

Implicit Euler Time-Discretization of a Class of Lagrangian Systems with Set-Valued Robust Controller

International audienceA class of Lagrangian continuous dynamical systems with set-valued controller and subjected to a perturbation force has been thoroughly studied in [S. Adly, B. Brogliato, B. K. Le, Well-posedness, robustness and stability analysis of a set-valued controller for Lagrangian systems, SIAM J. Control Optim., 51(2), 1592--1614, 2013]. In this paper, we study the time discretization of these set-valued systems with an implicit Euler scheme. Under some mild conditions, the well-posedness (existence and uniqueness of solutions) of the discrete-time scheme, as well as the convergence of the sequences of discrete positions and velocities in finite steps are assured. Furthermore, the approximate piecewise linear function generated by these discrete sequences is shown to converge to the solution of the continuous time differential inclusion with order $\frac{1}{2}$. Some numerical simulations on a two-degree of freedom example illustrate the theoretical developments

Stability of linear semi-coercive variational inequalities in Hilbert spaces: application to the Signorini-Fichera problem

International audienceIn this paper we show how recent results concerning the stability of semi-coercive variational inequalities in reflexive Banach spaces, obtained in [2] and [3] can be applied to establish the stability of the semi-coercive Signorini­ Fichera problem with respect to small perturbations

A Fenchel-Lagrange Duality Approach for a Bilevel Programming Problem with Extremal-Value Function

International audienceIn this paper, for a bilevel programming problem (S) with an extremal-value function, we first give its Fenchel-Lagrange dual problem. Under appropriate assumptions, we show that a strong duality holds between them. Then, we provide optimality conditions for (S) and its dual. Finally, we show that the resolution of the dual problem is equivalent to the resolution of a one-level convex minimization problem

Qualitative Stability of a Class of Non-Monotone Variational Inclusions. Application in Electronics

International audienceThe main concern of this paper is to investigate some stability properties (namely Aubin property and isolated calmness) of a special non-monotone variational inclusion. We provide a characterization of these properties in terms of the problem data and show their importance for the design of electrical circuits involving nonsmooth and non-monotone electronic devices like DIAC (DIode Alternating Current). Circuits with other devices like SCR (Silicon Controlled Rectifiers), Zener diodes, thyristors, varactors and transistors can be analyzed in the same way

Sliding Mode Observer for Set-valued Lur'e Systems and Chattering Removing

In this paper, we study a sliding mode observer for a class of set-valued Lur'e systems subject to uncertainties. We show that our approach has obvious advantages than the existing Luenberger-like observers. Furthermore, we provide an effective continuous approximation to eliminate the chattering effect in the sliding mode technique