Publications associées à Quotient method for stabilising a ball-on-a-wheel system – Experimental results

Stability: a search for structure

In this thesis we study stability from several viewpoints. After covering the practical importance, the rich history and the ever-growing list of manifestations of stability, we study the following. (i) (Statistical identification of stable dynamical syste ...

EPFL2024

Data-driven Methods for Control: from Linear to Lifting

Yingzhao Lian

The progress towards intelligent systems and digitalization relies heavily on the use of automation technology. However, the growing diversity of control objects presents significant challenges for traditional control approaches, as they are highly depende ...

EPFL2023

Numerical and experimental investigation of spiral-grooved gas journal bearings

Elia Iseli

Small-scale turbomachinery is increasingly used in carbon-free energy conversion systems, such as commercial or domestic scale heat pumps, fuels cells for transportation and waste heat recovery. The usage of aerodynamic bearings allows the design of compac ...

EPFL2022

Nonlinear Transient Stability Analysis of Phased-Locked Loop Based Grid-Following Voltage Source Converters Using Lyapunov’s Direct Method

Alireza Karimi, Behrooz Bahrani

In this paper, using Lyapunov’s stability theorem, the transient stability conditions for a grid-following Voltage Source Converter (VSC) are found. These conditions take into account both the grid specifications and the VSC’s dynamics. The derived conditi ...

2021

Second-order sensitivity in the cylinder wake: Optimal spanwise-periodic wall actuation and wall deformation

François Gallaire, Edouard Boujo, Andrea Fani

Two-dimensional (2D) flows can be controlled efficiently using spanwise "waviness," i.e., a control (e.g., wall blowing and suction or wall deformation) that is periodic in the spanwise direction. This study tackles the global linear stability of 2D flows ...

AMER PHYSICAL SOC2019

Low-Rank Updates And A Divide-And-Conquer Method For Linear Matrix Equations

Daniel Kressner, Stefano Massei

Linear matrix equations, such as the Sylvester and Lyapunov equations, play an important role in various applications, including the stability analysis and dimensionality reduction of linear dynamical control systems and the solution of partial differentia ...

SIAM PUBLICATIONS2019

Rayleigh-Taylor instability under a spherical substrate

Gioele Mariano Nicolò Balestra, François Gallaire, David Minh-Phuc Nguyen

We investigate the Rayleigh-Taylor instability of a thin viscous film coating the inside of a spherical substrate. The aim of this work is to find and characterize the instability pattern in this spherical geometry. In contrast to the Rayleigh-Taylor insta ...

2018

Compliant control of Uni/ Multi- robotic arms with dynamical systems

Seyed Sina Mirrazavi Salehian

Accomplishment of many interactive tasks hinges on the compliance of humans. Humans demonstrate an impressive capability of complying their behavior and more particularly their motions with the environment in everyday life. In humans, compliance emerges fr ...

EPFL2018

Wall-contact sliding control strategy for a 2D caged quadrotor

Dario Floreano, Przemyslaw Mariusz Kornatowski, Pu Bai

This paper addresses the trajectory tracking problem of a 2D caged flying robot in contact with a wall. To simplify the contact problem, the models are constructed on a vertical two-dimensional plane, and our objective is to let the quadrotor hover or move ...

IEEE2018

Dimensional stability analysis of a UV printed polymer microstructure for a novel glazing system

Yves Leterrier, Andreas Schueler, André Gabriel Kostro, Frank Meyer, Jing Gong

The dimensional stability of a UV printed polymer microstructure for a novel glazing system for seasonal regulation and daylighting based on a periodic array of parabolic micro-mirrors is investigated. The objectives of the work are: i) to analyze the dime ...

Elsevier2017

Polarization and Channel Ordering: Characterizations and Topological Structures

Rajai Nasser

Information theory is the field in which we study the fundamental limitations of communication. Shannon proved in 1948 that there exists a maximum rate, called capacity, at which we can reliably communicate information through a given channel. However, Sha ...

EPFL2017

The algebra of essential relations on a finite set

Jacques Thévenaz, Serge Bouc

Let X be a finite set and let k be a commutative ring. We consider the k-algebra of the monoid of all relations on X, modulo the ideal generated by the relations factorizing through a set of cardinality strictly smaller than Card(X), called inessential rel ...

Walter de Gruyter2016

The U (n) free rigid body: Integrability and stability analysis of the equilibria

Tudor Ratiu

A natural extension of the free rigid body dynamics to the unitary group U (n) is considered. The dynamics is described by the Euler equation on the Lie algebra u(n), which has a bi-Hamiltonian structure, and it can be reduced onto the adjoint orbits, as i ...

Elsevier2015

Integrable G-strands on semisimple Lie groups

Tudor Ratiu, François Gay-Balmaz

The present paper derives systems of partial differential equations that admit a quadratic zero curvature representation for an arbitrary real semisimple Lie algebra. It also determines the general form of Hamilton's principles and Hamiltonians for these s ...

Iop Publishing Ltd2014

Soft Constrained Model Predictive Control With Robust Stability Guarantees

Colin Neil Jones, Melanie Nicole Zeilinger

Soft constrained model predictive control (MPC) is frequently applied in practice in order to ensure feasibility of the optimization during online operation. Standard techniques offer global feasibility by relaxing state or output constraints, but cannot e ...

Institute of Electrical and Electronics Engineers2014

Multiplicative structure in equivariant cohomology

Kathryn Hess Bellwald

We introduce the notion of a strongly homotopy-comultiplicative resolution of a module coalgebra over a chain Hopf algebra, which we apply to proving a comultiplicative enrichment of a well-known theorem of Moore concerning the homology of quotient spaces ...

Elsevier2012

On the Brauer group of diagonal quartic surfaces

Evis Ieronymou

We obtain an easy sufficient condition for the Brauer group of a diagonal quartic surface D over Q to be algebraic. We also give an upper bound for the order of the quotient of the Brauer group of D by the image of the Brauer group of Q. The proof is based ...

2011

Steady-state Solutions in Mathematical Models of Atrial Cell Electrophysiology and their Stability

Vincent Jacquemet

The steady states of the Fenton–Karma, the Courtemanche and the Nygren cell models were studied by determining the fixed points of the dynamical system describing their cell kinetics. The linear stability of the fixed points was investigated, as well as th ...

2007

Symmetry breaking in mechanical systems

The first part of this thesis studies the problem of symmetry breaking in the context of simple mechanical systems with compact symmetry Lie group G. In this part we shall assume that the principal stratum of the G-action on the configuration space Q of a ...

EPFL2005