Publications related to Bouncing between model and data: stability, passivity, and optimality in hybrid dynamics

Dynamic Modeling of an Origami Prismatic Joint

Jamie Paik, Jian-Lin Huang, Mustafa Mete

Dynamic modeling of folding joints is critical for predicting dynamic behavior, optimizing design parameters, and developing control strategies for origami robots and machines. Although kinematics of the folded joints exists, little research describes thei ...

IEEE2023

Corona discharge actuator as an active sound absorber under normal and oblique incidence

Thomas Humbert, Hervé Lissek, Stanislav Sergeev

In the majority of active sound absorbing systems, a conventional electrodynamic loudspeaker is used as a controlled source. However, particular situations may require an actuator that is more resistant to harsh environments, adjustable in shape, and light ...

2022

Microscopic field theory for structure formation in systems of self-propelled particles with generic torques

Ignacio Pagonabarraga Mora, Elena Sesé Sansa

We derive a dynamical field theory for self-propelled particles subjected to generic torques and forces by explicitly coarse-graining their microscopic dynamics, described by a many-body Fokker-Planck equation. The model includes both intrinsic torques ind ...

AIP Publishing2022

Second-order adjoint-based sensitivity for hydrodynamic stability and control

Edouard Boujo

Adjoint-based sensitivity analysis is routinely used today to assess efficiently the effect of open-loop control on the linear stability properties of unstable flows. Sensitivity maps identify regions where small-amplitude control is the most effective, i. ...

Cambridge University Press2021

Stabilization of the linearized water tank system

Shengquan Xiang

In this article we study the so-called water tank system. In this system, the behavior of water contained in a 1-D tank is modelled by Saint-Venant equations, with a scalar distributed control. It is well-known that the linearized systems around uniform st ...

2022

Local Vulnerabilities and Global Robustness of Coupled Dynamical Systems on Complex Networks

Melvyn Sandy Tyloo

Coupled dynamical systems are omnipresent in everyday life. In general, interactions between individual elements composing the system are captured by complex networks. The latter greatly impact the way coupled systems are functioning and evolving in time. ...

EPFL2020

Invariant states in inclined layer convection. Part 1. Temporal transitions along dynamical connections between invariant states

Tobias Schneider, Florian Reetz

Thermal convection in an inclined layer between two parallel walls kept at different fixed temperatures is studied for fixed Prandtl number . Depending on the angle of inclination and the imposed temperature difference, the flow exhibits a large variety of ...

Cambridge University Press2020

Analysis of Spiral-Grooved Gas Journal Bearings by the Narrow-Groove Theory and the Finite Element Method At Large Eccentricities

Jürg Alexander Schiffmann, Eliott Philippe Guenat, Elia Iseli

A finite groove approach (FGA), based on the finite element method (FEM), is used for analyzing the static and dynamic behavior of spiral-grooved aerodynamic journal bearings at different eccentricities, number of grooves, and compressibility numbers. The ...

2020

Atomistic modeling of the solid-liquid interface of metals and alloys

Edoardo Baldi

Solidification is a phase transformation of utmost importance in material science, for it largely controls materials' microstructure on which a wide range of mechanical properties depends. Almost every human artifact undergoes a transformation that leads t ...

EPFL2020

Learning Augmented Joint-Space Task-Oriented Dynamical Systems:A Linear Parameter Varying and Synergetic Control Approach

Aude Billard, Seyed Sina Mirrazavi Salehian, Nadia Barbara Figueroa Fernandez, Yonadav Goldwasser Shavit

In this paper, we propose an asymptotically stable joint-space dynamical system that captures desired behaviors in joint-space while stably converging towards a task-space attractor. To encode joint-space behaviors while meeting the stability criteria, the ...

2018

A Linear-Quadratic Gaussian Approach to Dynamic Information Acquisition

Thomas Alois Weber, Viet Anh Nguyen

We consider optimal information acquisition for the control of linear discrete-time random systems with noisy observations and apply the findings to the problem of dynamically implementing emissions-reduction targets. The optimal policy, which is provided ...

2018

Characterization of the Photochemical Properties of 5-Benzyluracil via Time-Dependent Density Functional Theory

Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Sara Bonella, Mohammadhassan Valadan

We present a detailed study of the excited state properties of 5-benzyluracil (5BU) in the gas phase and in implicit solvent using different electronic structure approaches ranging from time-dependent density functional theory in the linear response regime ...

2017

Stabilization of electrodynamic bearings with active magnetic dampers

Qingwen Cui

Electrodynamic Bearings (EDBs) are a kind of passive magnetic bearings that exploits the interaction between the induced eddy currents in a conductor and a magnetic field to provide re-storing forces. They have been regarded as an appealing alternative to ...

EPFL2016

Passive Interaction Control With Dynamical Systems

Aude Billard, Klas Jonas Alfred Kronander

Autonomous dynamical systems (DS) has emerged as an extremely flexible and powerful method for modeling robotic tasks. Task execution of DS models is typically done in an open-loop manner in combination with standard low level controller, e.g. position con ...

2016

Sensitivity and open-loop control of stochastic response in a noise amplifier flow: the backward-facing step

François Gallaire, Edouard Boujo

The two-dimensional backward-facing step flow is a canonical example of noise amplifier flow: global linear stability analysis predicts that it is stable, but perturbations can undergo large amplification in space and time as a result of non-normal effects ...

Cambridge University Press2015

Dynamic stability of displacement-based atomistic/continuum coupling methods

Till Junge, Jean-François Molinari, Guillaume Anciaux

We show that concurrent atomistic/continuum displacement-coupling methods are inherently unstable in the context of fully dynamic problems at finite temperature. The fundamental origin of the instability is the displacement coupling of two material descrip ...

Elsevier2015

A Model Predictive Control scheme with Ultimate Bound for Economic Optimization

Colin Neil Jones, Andrea Alessandretti

This paper presents a Model Predictive Control (MPC) scheme for nonlinear continuous-time systems where an economic stage cost, which is not a measure of the distance to a desired set point, is combined with a classic stabilizing stage cost. The associated ...

2015

Model-Based Derivation, Analysis and Control of Unstable Microaerobic Steady-States-Considering Rhodospirillum rubrum as an Example

Timm Faulwasser

Microaerobic (oxygen-limited) conditions are critical for inducing many important microbial processes in industrial or environmental applications. At very low oxygen concentrations, however, the process performance often suffers from technical limitations. ...

Wiley-Blackwell2014

An adjoint-based approach to the optimal control of separated flows

Edouard Boujo

Flow separation is relevant to many industrial applications, since it is detrimental to the aerodynamic performance of vehicles, induces vibrations in mechanical structures, but can also contribute to improve mixing in combustion devices. In this thesis, t ...

EPFL2014

Accuracy of momentum and gyrodensity transport in global gyrokinetic particle-in-cell simulations

Laurent Villard, Ben McMillan

Gyrokinetic Particle-In-Cell (PIC) simulations based on conservative Lagrangian formalisms admit transport equations for conserved quantities such as gyrodensity and toroidal momentum, and these can be derived for arbitrary wavelength, even though previous ...

Amer Inst Physics2014