Publications related to Angular acceleration

3D printed large amplitude torsional microactuators powered by ultrasound

Mahmut Selman Sakar, Mehdi Ali Gadiri, Junsun Hwang, Amit Yedidia Dolev

Here, we introduce a design, fabrication, and control methodology for large amplitude torsional microactuators powered by ultrasound. The microactuators are 3D printed from two polymers with drastically different elastic moduli as a monolithic compliant me ...

2024

Mechanism balancing taxonomy

Simon Nessim Henein, Florent Cosandier, Hubert Pierre-Marie Benoît Schneegans

The balancing of mechanisms consists in distributing their moving masses, inertias, and elastic components in order to achieve key mechanical properties, such as the elimination of the shaking forces and moments exported onto their supporting structure or ...

2023

Strength and timing of primary and secondary vortices generated by a rotating plate

Karen Ann J Mulleners, Diego Francescangeli

Accurate predictions of how vortices grow, evolve, and separate from aerodynamic objects are desirable for various applications ranging from autonomous aerial vehicles to wind turbines. Here, we present an experimental characterisation of the formation pro ...

2023

Learning Physics-Consistent Particle Interactions

Olga Fink, David Simon Kammer, Zhichao Han

Interacting particle systems play a key role in science and engineering. Access to the governing particle interaction law is fundamental for a complete understanding of such systems. However, the inherent system complexity keeps the particle interaction hi ...

Oxford University Press2023

Analytical Studies in Support of an Improved Approach to the Design of Acceleration-Sensitive Nonstructural Elements

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

This paper summarizes a series of analytical studies that were conducted in connection with an improved approach for the design of acceleration-sensitive nonstructural elements. In the new approach, bracing to secure nonstructural elements to the structure ...

Applied Technology Council, Sponse2022

Estimating the non-dimensional energy of vortex rings by modelling their roll-up

Karen Ann J Mulleners, Guillaume de Guyon-Crozier

The non-dimensional energy of starting vortex rings typically converges to values around 0.33 when they are created by a piston-cylinder or a bluff body translating at a constant speed. To explore the limits of the universality of this value and to analyse ...

Cambridge University Press2022

Growth, timing, & trajectory of vortices behind a rotating plate

Diego Francescangeli

The presence of aerodynamic vortices is widespread in nature. They can be found at small scales near the wing tip of flying insects or at bigger scale in the form of hurricanes, cyclones or even galaxies. They are identified as coherent regions of high vor ...

EPFL2022

Proof Of Concept Of A Graphene-Based Resonant Accelerometer

Luis Guillermo Villanueva Torrijo, Daniel Moreno Garcia

Acceleration measurements are fundamental in applications such as consumer electronics, navigation, automotive safety and Internet of things (IoT). In comparison with capacitive or piezoresistive MEMS accelerometers, resonant graphene accelerometers have t ...

IEEE2021

Optical measurement method for mechanical time base characterization

Simon Nessim Henein, Etienne Frédéric Gabriel Thalmann

The recent adoption of silicon components by the mechanical watch industry has triggered the search for new time bases to advantageously replace the traditional balance and hairspring oscillator. In particular, flexure-based oscillators manufactured in sil ...

euspen2021

Shaking force balancing of a 2-DOF isotropic horological oscillator

Simon Nessim Henein, Hubert Pierre-Marie Benoît Schneegans, Etienne Frédéric Gabriel Thalmann

Despite centuries of research and significant advances, the escapement mechanism used to count and maintain oscillations of mechanical time bases remains a complex mechanism and a major source of energy losses. We showed in previous work that, instead of t ...

2021

A 4D printed active compliant hinge for potential space applications using shape memory alloys and polymers

Jamie Paik, Zhenishbek Zhakypov, Jian-Lin Huang, Ralph Spolenak

This paper presents the proof-of-concept for a 4D printed active compliant hinge with a selectively variable stiffness for the deployment and reorientation of satellite appendages. We use 4D printing to create an active compliant hinge capable of bending t ...

IOP PUBLISHING LTD2021

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

Statically and dynamically balanced oscillator based on Watt's linkage

Simon Nessim Henein, Hubert Pierre-Marie Benoît Schneegans, Ilan Vardi

We present a new mechanical oscillator architecture that can be made insensitive to linear and angular accelerations while keeping constant oscillation frequency. The oscillator has the kinematics of a Watt linkage, so we call it a Watt oscillator. In orde ...

EUSPEN2020

A hybrid control strategy for force and precise end effector positioning of a twisted string actuator

Jamie Paik, Andres San Millan Rodriguez

We propose a new control approach for the twisted string actuation (TSA) system; a hybrid control scheme consisting of two nested loops, considering the motor angle and the axial force at the clamping point of the actuator as the system outputs. We show th ...

2021

Comparison of gait characteristics between clinical and daily life settings in children with cerebral palsy

Kamiar Aminian, Anisoara Ionescu, Lena Carcreff, Stéphane Armand

Gait assessments in standardized settings, as part of the clinical follow-up of children with cerebral palsy (CP), may not represent gait in daily life. This study aimed at comparing gait characteristics in laboratory and real life settings on the basis of ...

Nature Research2020

Angular Momentum in Rotating Superfluid Droplets

Christoph Bostedt, Camila Bacellar Cases Da Silveira

The angular momentum of rotating superfluid droplets originates from quantized vortices and capillary waves, the interplay between which remains to be uncovered. Here, the rotation of isolated submicrometer superfluid He-4 droplets is studied by ultrafast ...

AMER PHYSICAL SOC2020

On the Dynamics of Magnetic Swimmers in Stokes Flow

Pauline Marie Rüegg-Reymond

In the past decade, the engineering community has conceived, manufactured and tested micro-swimmers, i.e. microscopic devices which can be steered in their intended environment. Foreseen applications range from microsurgery and targeted drug delivery to en ...

EPFL2019

Data-driven Measurement Designs for Magnetic Resonance Imaging

Baran Gözcü

Despite being a powerful medical imaging technique which does not emit any ionizing radiation, magnetic resonance imaging (MRI) always had the major problem of long scanning times that can take up to an hour depending on the application. It also requires u ...

EPFL2019

Range-based underwater target localization using an autonomous surface vehicle: Observability analysis

In the field of marine robotics, the problem of range based underwater target localization can be defined as that of localizing an unknown - fixed or moving - target from a surface vehicle called the tracker, using range information available about the tar ...

2018

A co-rotational scroll machine

Jürg Alexander Schiffmann, Luis Carlos Mendoza Toledo

A co-rotating scroll machine operable as compressor or expander, comprises a transmission and guidance mechanism (9,10) for first and second scroll plates (7,8), having three transmission and guidance units (9,10) uniformly distributed around the scroll pl ...

2018