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Boulandet Romain

Main skills

Modeling and simulation

Main contract

Desktop: A122

Haute école du paysage, d'ingénierie et d'architecture de Genève
Rue de la Prairie 4, 1202 Genève, CH

Faculty
Technique et IT

Main Degree Programme
Microtechniques

MSc HES-SO en Engineering - HES-SO Master

Applied Vibration and Acoustics
Master of Advanced Studies HES-SO en Conception horlogère

BSc HES-SO en Microtechniques - Haute école du paysage, d'ingénierie et d'architecture de Genève

Physique appliquée
Acoustique Appliquée
Physique des vibrations

Ongoing

ClickSound

Role: Main Applicant

Financement: Mandat de recherche

Description du projet :

This project focuses on the design, fabrication, and delivery of an automated, precisely controllable activation system for high-accuracy acoustic measurements of auto-injectors. Developed in collaboration with the Robotics and Automation Group, the solution features an ultra-low-noise activation mechanism integrated within a compact anechoic chamber fitted with a measurement microphone. The system is fully operated via custom software, enabling efficient recording, processing, and analysis of acoustic data.

Research team within HES-SO: Boulandet Romain , Olivier Jeremy , Chambordon Marc , Humbert Norah , Delprete Vincent

Montant global du projet: 23'200 CHF

Statut: Ongoing

Completed

Binaural sOund dOsimeter for Musicians.

AGP

Role: Main Applicant

Financement: HES-SO Rectorat; HUG

Description du projet : La surdité reste l'une des maladies à caractère professionnel les plus répandues car des millions de salariés sont régulièrement exposés à des niveaux de bruit élevés1. Facteur de stress, les nuisances sonores peuvent à plus long terme provoquer des dysfonctionnements de l'oreille, tels que des bourdonnements ou des acouphènes, et dans les cas les plus extrêmes une surdité. Une fois le dommage auditif constaté, le handicap social et psychologique infligé aux salariés peut également engendrer des coûts très importants pour l'entreprise et la collectivité (indemnisation, perte de compétences, retraite anticipée, etc.). Cette souffrance, qui augmente avec l'âge, va malheureusement de pair avec une détérioration des compétences sociales, une difficulté à communiquer dans des environnements bruyants et un isolement qui, à l'ère de la société de la communication, entraîne une forte demande d'appareillage et de rééducation.

Research team within HES-SO: Chambordon Marc , Boulandet Romain , Goundiaev Kirill , Sanchez Mejia Victor

Partenaires académiques: HEPIA inTECH; Boulandet Romain, HEPIA inTECH

Durée du projet: 01.04.2024 - 31.03.2025

Montant global du projet: 5'000 CHF

Statut: Completed

Mechanical, chemical & structure properties of acoustic materials.

AGP

Role: Collaborator

Requérant(e)s: Boulandet Romain, HEPIA inTECH, Milosevic Irena, HEPIA inTECH

Financement: HES-SO Rectorat; Hidden Sound GmbH

Description du projet : The acoustic materials are highly porous and have specific mechanical and structure properties in order to produce sound effects. Some woods are known for centuries as the excellent acoustic materials and thus used for building of music instruments (as the violine). It was early recognized that properties of individual wood pieces of the same wood type can have very different acoustic performance. When going into smaller size pieces of an acoustic material, this effect is even more pronounced. For example: balsa wood is known as a great acoustic material for a long time, but the 100 different pieces of balsa wood having for example 4mm thickness, often have the different material properties (chemical, mechanical and structure) between them. The consequence is a different acoustic response of these pieces of the same material. But, this issue is not only happening with woods, as natural materials, but also with engineered materials, as acoustic foams made from various polymers.

Research team within HES-SO: Mionic Ebersold Marijana , Chambordon Marc , Boulandet Romain , Milosevic Irena , Leduc Louise , Van Der Ben Marco

Partenaires académiques: Boulandet Romain, HEPIA inTECH; Milosevic Irena, HEPIA inTECH

Durée du projet: 30.05.2024 - 01.03.2025

Montant global du projet: 67'000 CHF

Statut: Completed

Modal ActivE abSorber for Technical ROom (MAESTRO)

Role: Collaborator

Financement: HES-SO Rectorat; Relec SA

Description du projet :

Le projet MAESTRO (Modal ActivE abSorber for Technical Room) porte sur l’amélioration d’une technologie d’absorption acoustique active destinée à réduire les nuisances sonores dans des espaces fermés.

Les équipements d’un bâtiment (conduit de ventilation, pompe à chaleur, ascenseur, etc.) peuvent s’avérer gênants, ponctuellement ou de façon continue, avoir différents impacts sonores que l’on cherche à minimiser. Les bruits à basse fréquence sont particulièrement problématiques pour les usagers. En effet, les longueurs d’onde émises sont typiquement de l’ordre de grandeur des dimensions du local, ce qui tend à amplifier l’énergie acoustique par effet de résonance (modes propres) causé par de multiples réflexions inévitables. Le problème est que les matériaux acoustiques conventionnels ne sont pas efficaces dans cette plage de fréquence, ou sont trop encombrants et coûteux à mettre en œuvre.

À l’aide d’une technologie active constituée d’un ou plusieurs haut-parleurs commandés par un signal de pression en champ proche, a.k.a AVAA (Active Velocity Acoustic Absorber) développée par PSI Audio (Yverdon), il est possible de réduire le niveau sonore en absorbant activement l'énergie des modes de la pièce. Comme dans tout système asservi, en revanche, la stabilité est une performance à satisfaire en priorité. Les instabilités observées dans la pratique sont essentiellement liées à la dynamique interne des transducteurs, à la latence dans la boucle de contrôle, ainsi qu’au couplage acoustique avec la salle dont les premiers modes propres interagissent fortement avec le dispositif actif.

Les modèles numériques ont permis de vérifier un certain nombre d'hypothèses de départ sur l’impédance ciblent à réaliser pour une absorption efficace, d'étudier les performances et la sensibilité de la réponse du dispositif aux paramètres influençant la stabilité (latence, position, caractéristiques de la pièce) et de fournir des éléments pour le dimensionnement d'un nouvel absorbeur. Le projet a abouti à une nouvelle conception d'absorbeur contrôlée par un principe innovant de détection de la pression en champ proche, ainsi qu'à la production d'un démonstrateur qui a été testé en laboratoire dans une pièce réelle.

Research team within HES-SO: Boulandet Romain

Partenaires professionnels: Yvan Bécher, Relec SA, Yverdon

Durée du projet: 01.05.2023 - 02.05.2024

Montant global du projet: 55'000 CHF

Statut: Completed

Electroacoustic room sensor for safety (EARSENS)

Role: Main Applicant

Financement: HES-SO Rectorat

Description du projet :

La surveillance d'un bâtiment nécessite généralement la mise en œuvre de diverses technologies de capteurs. En plus d'en contrôler l'accès, les données recueillies servent aussi à adapter l'éclairage, le chauffage, la ventilation, la climatisation et le ménage en fonction de l'activité humaine et des besoins réels des occupants. Cela permet une gestion efficace de l'énergie et une réduction des coûts d'exploitation. Cependant, certaines technologies de capteurs sont relativement lourdes et coûteuses à mettre en œuvre ou susceptibles d’interférer avec les questions de confidentialité.

Le projet EARSENS (Electroacoustic room sensor for safety) vise à développer une technologie innovante et respectueuse de la vie privée pour la surveillance des paramètres de sécurité dans un bâtiment. L'approche alternative proposée dans cette recherche consiste à utiliser un haut-parleur électrodynamique classique associé à un algorithme d’intelligence artificielle pour différencier les classes d'événements en fonction des petites variations qu'ils produisent dans le champ sonore intérieur. Les chercheur-es d’HEPIA ont d’abord montré par simulation et expérimentation qu’un certain nombre d’évènements intérieurs tels que l'ouverture et la fermeture de portes et de fenêtres, la présence de personnes, le déplacement de mobilier, une élévation ou une baisse anormale de la température, modifiaient de manière significative le comportement modal de la pièce. Un modèle a été établi permettant d’estimer la charge acoustique exercée par la salle sur la membrane du haut-parleur sans avoir à recourir à des capteurs externes. Puis, un algorithme de type réseau de neurones à convolution (ou CNN) a été entraîné à reconnaître au sein d’une base d’apprentissage issues de données expérimentales les motifs récurrents spécifiques aux évènements d’intérêt. Ce dispositif tire ainsi profit du couplage acoustique qui existe entre le haut-parleur et une salle dans les basses fréquences, et de la réciprocité du principe de transduction électrodynamique permettant d’utiliser le haut-parleur simultanément en mode capteur/actuateur.

Ce projet a abouti à la réalisation d'un démonstrateur qui a permis de tester puis de valider le concept dans des salles réelles. Ne collectant aucune donnée sensible (ni parole, ni vidéo), le dispositif EARSENS concilie sécurité et respect de la vie privée, en plus d'être simple à mettre en œuvre et relativement abordable.

Research team within HES-SO: Boulandet Romain

Durée du projet: 01.07.2020 - 01.04.2022

Statut: Completed

2024

Optimizing a 2D active set-up for global control of low-frequency wall reflections in a semi-anechoic room

Scientific paper ArODES

Emmanuel Friot, Cédric Pinhède, Philippe Herzog, Romain Boulandet

Acta Acustica, 8, 68

Link to the publication

Summary:

Numerical simulations were carried out to optimize the design of an active semi-anechoic room. The active set-up includes control sources and microphones near the room ceiling and walls. The objective is to achieve global control, around an a priori unknown primary source, of the low-frequency wall reflections that are not adequately managed by absorbing material. The control strategy is based on the estimation, by linear filtering of total pressure signals, of the scattered pressure at minimization points meshing the room ceiling and walls. The required filters are identified off-line from measurements with a source whose radiation pattern is known. A 2D simple modal model is used to simulate active control in the frequency domain. The location of the minimization points, the set of estimation microphones and the method for computing the control signals from the measurements are varied. Simulations show that i) efficient global control of the scattered pressure can be achieved over a wide frequency band with a single non-smooth layer of minimization points, ii) accurate scattered pressure estimation at the minimization points can be achieved using usual pressure microphones distributed over all walls, iii) a Remote-Microphone technique seems slightly preferable to an Additional-Filter method for calculating the control signals.

Towards an active semi-anechoic room:

Scientific paper ArODES

simulations and first measurements

Cédric Pinhède, Romain Boulandet, Emmanuel Friot, Mark R. Allado, Renaud Côté, Philippe Herzog

Acta Acustica, 2024, 8, 56

Link to the publication

Summary:

Semi-anechoic rooms are used for the acoustic characterisation of noise sources. They involve heavy infrastructures and thick absorbent lining. The aim of this work is to demonstrate a less expensive alternative by complementing a thin passive coating with an active technology. Previous work has achieved the active reduction of the pressure scattered by the reflective wall of a semi-anechoic room, in the 80–200 Hz frequency band. This work validated an innovative approach allowing to control the scattered pressure throughout the measurement volume, using a setup located over its periphery. This paper extends a previous presentation at Forum Acusticum dealing with the active control of the low-frequency reflections on the walls and ceiling of a semi-anechoic room [Pinhède et al., Forum Acusticum 2023, Torino, Italy, 11–15 September, 2023, https://doi.org/10.61782/fa.2023.0399]. We describe the design principles and the 2D semi-analytical and 3D finite element simulations of the control system that help optimise parameters such as the transducers number and locations. A full-scale demonstrator has been built to validate the control strategy. Acoustics measurements, which have been used to characterise the room acoustics and to update the simulation parameters are also presented and compared to an updated numerical model.

2023

Towards the detection and classification of indoor events using a loudspeaker

Scientific paper ArODES

Patrick Marmaroli, Mark Allado, Romain Boulandet

Applied Acoustics, 2023, vol. 202, article no. 109161

Link to the publication

Summary:

In recent decades, smart building has received considerable research attention due to the increased demand for connected and integrated technology. Based on data collected by sensors, alarms, lighting, access control, heating and cleaning can be adjusted according to human activity and the actual needs of the occupants, resulting in efficient energy management and operating cost savings. However, in most cases, these sensors are application-specific, which limits their usefulness and scalability. Of the available sensing technologies, acoustic methods often rely on the use of microphones, which can lead to privacy issues. In this work, we use an electrodynamic loudspeaker in combination with a convolutional neural network algorithm to extract and classify the features of indoor events from the sound field. We show how the loudspeaker impedance is sensitive, through the modal response of the room, to changes in occupancy or room layout (presence of people, movement or removal of furniture), door or window opening, or temperature variation. This gives the speaker a new functionality in addition to audio broadcasting. Theoretical analysis and experiments in real rooms demonstrate the accuracy and effectiveness of this acoustic-based approach for supervised classification of indoor events.

2024

Optimization of an active device for global control of low-frequency wall reflections in a semi-anechoic room

Conference ArODES

Emmanuel Friot, Cédric Pinhède, Philippe Herzog, Romain Boulandet

Proceedings of 53rd International Congress & Exposition on Noise Control Engineering, Inter-Noise 2024, 25-29 August 2024, Nantes, France

Link to the conference

Summary:

An active device has been designed and built at LMA to control low-frequency reflections on the absorbing walls of a semi-anechoic room: the sound pressure reflected by the walls in the presence of an unknown source is estimated by linear filtering of the total sound pressure near the walls, then neutralized using acoustic sources placed on the walls. Here, we present 2D numerical simulations, involving monopole sources and series of damped analytic modes, which have enabled us to optimize the active device, in particular to (i) deal with resonance frequencies at which cancelling the diffracted pressure near the walls is not sufficient to cancel it inside the room, (ii) minimize the number of the total pressure measurement points required to estimate the pressure diffracted by the walls at each location, and (iii) select the strategy for minimizing the virtual signals corresponding to the diffracted pressure. Simulations show that with the optimized device, the control remains efficient up to frequencies corresponding to one wall source per wavelength and a little less than two pressure sensors per wavelength. Experiments are underway to compare measurements with simulations.

2023

Simulation of a hybrid (active/passive) acoustic measurement room

Conference ArODES

Romain Boulandet, Mark Rallie Allado, Cédric Pinhède, Emmanuel Friot, Renaud Côte, Philippe Herzog

COMSOL Conference 2023 Munich

Link to the conference

Summary:

The ideal way to measure the acoustic performance of heavy items such as vehicles or machines is in a semi-anechoic chamber, i.e. in an environment with no reflections except from the solid floor where the noise source is standing. To accurately measure low frequencies down to 20 Hz (lower limit of the audible frequency range), the walls and ceiling of the room should be non-reflective down to 20 Hz. This is a practical challenge as usual (passive) rooms involve absorbing material (wedges) on the anechoic walls, leading to a lower cut-off frequency related to the wedge thickness: the lower frequency limit corresponds to a thickness close to a quarter of the longest wavelength to be absorbed. For example, a typical wedge length of 0.9 m gives good measurements down to around 100 Hz. An anechoic chamber accurate to 20 Hz would therefore require more than 4 m thick wedges to provide adequate low-frequency absorption: such a test facility would be quite difficult to build and excessively expensive. An alternative has recently been proposed: the DADA (Dome Anti-Diffraction Acoustique). This hybrid control approach combines a thin layer of absorbent (passive) materials with an active system driving a set of loudspeakers designed to cancel out the low-frequency pressure field scattered by the walls. In this paper, we present the scattered field control strategy for room reflections and its implementation in a COMSOL Multiphysics model using the Pressure Acoustics, Frequency Domain interface and LiveLink™ for MATLAB® to run simulations. Results computed in a lightly damped rectangular room over a frequency range of 20 Hz to 200 Hz are provided to show the performance and limitations of the DADA solution in cancelling the scattered pressure field.

2022

Simulations d’un dispositif de semi-anéchoïcité active

Conference ArODES

Cédric Pinhède, Mark Rallie Allado, Romain Boulandet, R. Cote, Emmanuel Friot, Philippe Herzog

Actes du 16e Congrès Français d'Acoustique CFA2022, 11-15 Avril 2022, Marseille, France

Link to the conference

Summary:

Les salles semi-anéchoïques sont utilisées en recherche et pour la caractérisation acoustique de produits industriels. La réalisation de ces salles implique actuellement des infrastructures lourdes et des revêtements absorbants onéreux. L'objectif du projet Dôme Anti-Diffraction Acoustique (DADA) est de montrer qu'il est possible de réaliser une salle semi-anéchoïque à moindre coût, en complétant un revêtement passif par une technologie active. Ce projet vise à réaliser un démonstrateur fonctionnel grandeur nature qui serait aussi un jalon important avant la réalisation de la salle anéchoïque active du Laboratoire de Mécanique et d'Acoustique. De premiers travaux ont permis une première démonstration d'anéchoïcité active consistant à rendre invisible acoustiquement, dans la bande de fréquence 80-200 Hz, la paroi réfléchissante d'une salle semi-anéchoïque à partir d'un réseau de neuf sources anti-bruit et seize microphones. Ces résultats valident aussi une approche novatrice qui consiste à contrôler la pression acoustique à proximité des parois pour obtenir une annulation de la pression dans le volume de mesure. Cette approche comporte plusieurs avantages-notamment celui d'éviter de placer des microphones (et leur supports) dans le volume de mesure, ainsi totalement libéré pour les besoins expérimentaux. Le projet DADA proposé ici s'appuie sur ces résultats mais avec une complexité significativement accrue car il s'agit d'effacer l'effet de cinq parois. La présentation rappellera la méthode d'anéchoïcité active développée au LMA et présentera les premiers résultats de simulation de contrôle du champ réfléchi par cinq parois.

2021

Implementation and performance assessment of a MEMS-based sound level meter

Conference ArODES

Savanne Rémy Kham, Patrick Marmaroli, Jordan Minier, Romain Boulandet

Proceedings of Euronoise 2021, 25-27 October 2021, Madeira, Portugal (online)

Link to the conference

Summary:

Long-established industries in rural areas are now creating noise issues for new communities that have developed nearby. Proactive control of noise emission has therefore become a priority for industries concerned with respecting the tranquillity of residents. The traditional method of noise monitoring utilizes a sound level meter (SLM) which must be installed to areas of interest by trained and experienced personnel. Since a class 1 SLM is relatively expensive, long-term monitoring of large areas can hardly be considered. In this paper, we discuss the practical implementation of a stand-alone MEMS-based SLM capable of recording one-minute time samples and wirelessly transmitting sound level values in third octave bands in the range from 20 Hz to 8 kHz, every 15 minutes. The current prototype uses a digital MEMS microphone with I2S interface connected to an Arduino MKR WiFi 1010 microcontroller for an overall cost of less than 100 CHF. Technical choices for the implementation of the prototype as well as a benchmark with a class 1 SLM are discussed in this paper.

2020

Aeroacoustic measurements on a free-flying drone in a WindShaper wind tunnel

Conference ArODES

Roberto Putzu, Romain Boulandet, Benjamin Rutschmann, Thierry Bujard, Flavio Noca, Catry Guillaume, Nicolas Bosson

Proceedings of Quiet drones 2020 - International e-Symposium on Noise of UAV and UAS, 19-21st October 2020, Paris, France

Link to the conference

Summary:

In the near future, drone usage in inhabited areas is expected to grow exponentially. The inherent noise generated is one of the concerns for this kind of vehicle. Conventional aeroacoustic wind tunnels can be used to investigate uniform-flow generated noise. Flyers are generally solidly tethered to a sting in these wind tunnels. However, the interaction of complex environmental flows with the drone fans is expected to generate different harmonic content, especially during unsteady maneuvers. Being able to probe the aeroacoustic signature of a free-flying drone in a realistic urban and wind environment is a necessity, in particular for future certification procedures. We have developed a new family of wind tunnels, the “WindShaper” (Noca et al. 2019 Wind and Weather Facility for Testing Free-Flying Drones, AIAA Aviation Forum), able to generate complex unsteady flows reproducing environmental gusts and shear flows. The WindShaper consists of an array of a large number of fans (wind-pixels) that may be arranged in various patterns on demand. It is in some ways a digital wind facility that can be programmed to generate arbitrary winds of variable intensity and direction. Various weather conditions (such as rain, snow, hail, fog etc.) that reflect real world situations can be introduced. Drones are in a free-flight configuration (untethered) as in their natural state. These tests can rate drones according to their capacity in maintaining a proper flight attitude and tackling flight perturbations, especially in an urban environment. A WindShaper was modified in order to allow aeroacoustic measurements around a freeflying drone in a turbulent flow. Particular attention was given to a design that allows the drone aeroacoustic signature to be segregated from the aeroacoustic signature of the multi-fan facility. Details on the results achieved in this new infrastructure will be presented and discussed.

2019

Sensorless measurement of the acoustic impedance of a loudspeaker

Conference ArODES

Romain Boulandet

Proceedings of the 23rd International Congress on Acoustics, 9-13 September 2019, Aachen, Germany

Link to the conference

Summary:

This paper presents an experimental approach for estimating the front-side radiation impedance of a loudspeaker. This acoustic load impedance is the reaction of the sound field on the radiating diaphragm which may affect the loudspeaker response, particularly in the low freqauencies due to the coupling with the room modes. In general, this impedance can not be solved analytically because it depends both on the physical characteristics of the speaker and the complexity of the acoustic field in which it radiates. Conventional measurement techniques require sensors such as microphones and accelerometers. The approach proposed here relies mainly on the the reciprocal mechanism of electrodynamic transduction, making it possible to use the loudspeaker as a sensor simultaneously. This work shows that the front-side acoustic impedance can be derived from the speaker input impedance and the knowledge ot its electromechanical parameters. An analytical model is given and data measured in actual rooms provides proof of concept. Potential applications are also discussed.

2018

Tunable flat-plate absorber design for active sound absorption

Conference ArODES

Kristinn Bjornsson, Romain Boulandet, Hervé Lissek

Proceedings of COMSOL Conference, 14 October 2018, Lausanne Switzerland

Link to the conference

Summary:

Noise reduction at low frequencies is a major issue in many workspaces and indoor public places. Unlike mid- and high-frequency noise, low frequency noise is less attenuated by using conventional sound absorbing materials. This communication proposes an electro-mechano-acoustic absorber model that couples three physical domains using plate vibration and sound radiation theories. The mechanical system is an elastically suspended plate specifically developed to favor the piston-like movement thereof. An electromechanical transducer is attached to the plate in order to tailor its dynamic response to incident pressure waves, thereby improving the sound absorption capacity of the system. Structural Mechanics module and Acoustics module are used in this study. We present the design and modeling of this electro-mechano-acoustic system, including the feedback control law which allows to turn it into a tunable electroacoustic absorber. The acoustic performance experimentally achieved from a prototype absorber are then compared to the simulation results.

Achievements

PEOPLE@HES-SO
Directory and Skills inventory

Boulandet Romain

Main skills

Acoustique

Vibroacoustique

Simulations numériques

Acoustics

vibration

Modeling and simulation

PEOPLE@HES-SO Directory and Skills inventory

Boulandet Romain

Main skills

Acoustique

Vibroacoustique

Simulations numériques

Acoustics

vibration

Modeling and simulation

PEOPLE@HES-SO
Directory and Skills inventory