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Concept

Cycle limite

Publications associées (27)

Stability: a search for structure

Wouter Jongeneel

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

Percolation and phase behavior in cellulose nanocrystal suspensions from nonlinear rheological analysis

Tiffany Abitbol

We examine the influence of surface charge on the percolation, gel-point and phase behavior of cellulose nanocrystal (CNC) suspensions in relation to their nonlinear rheological material response. Desulfation decreases CNC surface charge density which lead ...

ELSEVIER SCI LTD2023

Microscopic picture of paraelectric perovskites from structural prototypes

Nicola Marzari, Giovanni Pizzi, Michele Kotiuga

We highlight with first-principles molecular dynamics the persistence of intrinsic < 111 > Ti off-centerings for BaTiO3 in its cubic paraelectric phase. Intriguingly, these are inconsistent with the Pm (3) over barm space group often used to atomistically ...

AMER PHYSICAL SOC2022

Learning dynamical systems with bifurcations

Aude Billard, Farshad Khadivar, Ilaria Lauzana

Trajectory planning through dynamical systems (DS) provides robust control for robots and has found numerous applications from locomotion to manipulation. However, to date, DS for controlling rhythmic patterns are distinct from DS used to control point to ...

Elsevier2021

Automatic locking of a parametrically resonating, base-excited, nonlinear beam

Amit Yedidia Dolev

Described is a closed-loop control scheme capable of stabilizing a parametrically excited nonlinear structure in several vibration modes. By setting the relative phase between the spatially filtered response and the excitation, the open-loop unstable solut ...

SPRINGER2021

Topological Linear System Identification via Moderate Deviations Theory

Daniel Kuhn, Wouter Jongeneel, Tobias Sutter

Two dynamical systems are topologically equivalent when their phase-portraits can be morphed into each other by a homeomorphic coordinate transformation on the state space. The induced equivalence classes capture qualitative properties such as stability or ...

2022

High Li-ion conductivity in tetragonal LGPO: A comparative first-principles study against known LISICON and LGPS phases

Nicola Marzari, Leonid Kahle, Aris Marcolongo, Giuliana Materzanini

We highlight fast Li-ion diffusion in hypothetical tetragonal Li10GeP2O12 (LGPO), as a counterpart to the well-known phases of orthorhombic (LISICON) LGPO, thio-LISICON, and tetragonal Li10GeP2S12 (LGPS). We use extended Car-Parrinello molecular dynamics i ...

AMER PHYSICAL SOC2021

Effects of leading-edge separation on the vortex-induced vibration of an elongated bluff body

Guiyue Duan

Wind-tunnel experiments were conducted to investigate the effects of leading-edge separation on the vortex-induced vibration (VIV) of an elastically-supported elongated bluff body. Solid wind barriers of various heights were fixed in the leading edge to ad ...

ELSEVIER2021

Force Adaptation in Contact Tasks with Dynamical Systems

Aude Billard, Mahdi Khoramshahi, Walid Amanhoud

In many tasks such as finishing operations, achieving accurate force tracking is essential. However, uncertainties in the robot dynamics and the environment limit the force tracking accuracy. Learning a compensation model for these uncertainties to reduce ...

IEEE2020

Geometric mixing

Nicolas Piro Mastracchio

Mixing fluids often involves a periodic action, like stirring one's tea. But reciprocating motions in fluids at low Reynolds number, in Stokes flows where inertia is negligible, lead to periodic cycles of mixing and unmixing, because the physics, molecular ...

ROYAL SOC2020

Jamming with Tunable Roughness

Matthieu Wyart

We introduce a new model to study the effect of surface roughness on the jamming transition. By performing numerical simulations, we show that for a smooth surface, the jamming transition density and the contact number at the transition point both increase ...

AMER PHYSICAL SOC2020

Bidirectional motion of filaments: the role of motor proteins and passive cross linkers

Ignacio Pagonabarraga Mora

In eukaryotic cells, motor proteins (MPs) bind to cytoskeletal filaments and move along them in a directed manner generating active stresses. During cell division a spindle structure of overlapping antiparallel microtubules forms whose stability and dynami ...

Royal Soc Chemistry2017

A self-consistent model for the saturation dynamics of the vortex shedding around the mean flow in the unstable cylinder wake

François Gallaire, Vladislav Mantic Lugo

The supercritical instability leading to the Benard-von Karman vortex street in a cylinder wake is a well known example of supercritical Hopf bifurcation: the steady solution becomes linearly unstable and saturates into a periodic limit cycle. Nonetheless, ...

Amer Inst Physics2015

Secondary instability and tertiary states in rotating plane Couette flow

Tobias Schneider

Recent experimental studies have shown rich transition behaviour in rotating plane Couette flow (RPCF). In this paper we study the transition in supercritical RPCF theoretically by determination of equilibrium and periodic orbit tertiary states via Floquet ...

Cambridge University Press2014

Coupling Movement Primitives: Interaction With the Environment and Bimanual Tasks

Auke Ijspeert

The framework of dynamic movement primitives (DMPs) contains many favorable properties for the execution of robotic trajectories, such as indirect dependence on time, response to perturbations, and the ability to easily modulate the given trajectories, but ...

Ieee-Inst Electrical Electronics Engineers Inc2014

A General Family of Morphed Nonlinear Phase Oscillators with Arbitrary Limit Cycle Shape

Auke Ijspeert, Jesse van den Kieboom, Mostafa Ajallooeian

We present a general family of nonlinear phase oscillators which can exhibit arbitrary limit cycle shapes and infinitely large basins of attraction. This general family is the superset of familiar control methods like PD-control over a periodic reference, ...

Elsevier Science Bv2013

Modulation of motor primitives using force feedback: Interaction with the environment and bimanual tasks

Auke Ijspeert

The framework of dynamic movement primitives allows the generation of discrete and periodic trajectories, which can be modulated in various aspects. We propose and evaluate a novel modulation approach that includes force feedback and thus allows physical i ...

IEEE2013

Dynamical Movement Primitives: Learning Attractor Models for Motor Behaviors

Auke Ijspeert

Nonlinear dynamical systems have been used in many disciplines to model complex behaviors, including biological motor control, robotics, perception, economics, traffic prediction, and neuroscience. While often the unexpected emergent behavior of nonlinear ...

Massachusetts Institute of Technology Press2013

Thermodynamic stability of alkali-metal-zinc double-cation borohydrides at low temperatures

Nicola Marzari, Riccardo Sabatini

We study the thermodynamic stability at low temperatures of a series of alkali-metal-zinc double-cation borohydrides, including LiZn(BH4)(3), LiZn2(BH4)(5), NaZn(BH4)(3), NaZn2(BH4)(5), KZn(BH4)(3), and KZn2(BH4)(5). While LiZn2(BH4)(5), NaZn(BH4)(3), NaZn ...

American Physical Society2013

Time-Delayed Interactions in Networks of Self-Adapting Hopf Oscillators

Max-Olivier Hongler, Julio Rodriguez, Philippe Blanchard

A network of coupled limit cycle oscillators with delayed interactions is considered. The parameters characterizing the oscillator’s frequency and limit cycle are allowed to self-adapt. Adaptation is due to time-delayed state variables thatmutually interac ...

2013