Category: news

12-13-2021 PhD Defense of Ornella Tortorici

The Office of doctoral Studies is pleased to inform you that
Mrs Ornella TORTORICI
PhD candidate at COSMER & IM2NP laboratories with Doctoral School 548 « Sea & Sciences »
Under the supervision of M. Vincent HUGEL, Professor, Université de Toulon (France)
&

M. Hervé BARTHELEMY, Professor, University of Toulon (France), Codirecteur de thèse

supervised by M. Cédric ANTHIERENS, Assistant Professor, University of Toulon (France)

will defend her thesis to obtain the degree of Doctor

Discipline : « Automatic, Signal, Productics, Robotics »

on the thème

Design and automatic control of an instrumented umbilical for underwater robots
 

Monday December 13, 2021 at 1:30 pm

at University of Toulon – Campus La Garde – Amphi Building M

in front of the following jury

 

  • M. Benoit CLEMENT, Professor, ENSTA Bretagne, reviewer
  • M. Vincent CREUZE, Assistant professor, University of Montpellier , reviewer
  • M. Gérard POISSON, Professor, IUT de BOURGES, examiner
  • M. Cédric ANTHIERENS, Assistant professor, University of Toulon, co-supervisor
  • M. Hervé BARTHELEMY, Professor, University of Toulon, supervisor
  • M. Vincent HUGEL, Professor, University of Toulon, co-supervisor
  • Mme Elisabeth MURISASCO, Professor, University of Toulon, invited

Abstract

Remotely operated underwater robots (ROV) are connected by an umbilical to communicate with their control station on the surface. This umbilical has a safety advantage as a physical link to the robot but also impacts the system by transmitting forces and disturbances to the ROV, increasing the risk of snags and limiting its working range. This thesis focuses on the active management of umbilical connected to small ROVs in order to limit their impact on the system.

The forces transmitted by the cable to the ROV are studied as a function of different parameters thanks to the chain model and then thanks to the construction of a finite solids model under Matlab Simulink. A simple method of estimating the torsional stiffness and bending stiffness coefficients of the cable is proposed to parameterize these models.

A solution to control the cable distribution by a reel based on its instrumentation with a passive compliance system and a bending sensor is then proposed. This solution is evaluated through simulations of the complete system under Vortex and tank tests of the ROV with its cable instrumented and controlled by the reel. The experiments showed the feasibility of the automatic control of the cable at a reasonable length adapted to the movements of the ROV thanks to its instrumentation.

Key words : Underwater robotics, Mechatronic design, Active management of instrumented umbilical

Abstract

Design and control of actuated tether for underwater robots

Remotely operated vehicles in underwater (ROV) are connected by an umbilical to communicate with their control unit on the surface. This umbilical has a safety advantage as a physical link to the robot but also impacts the system by transmitting forces and disturbances to the ROV, thus increasing the risk of snags and limiting its working range. This thesis focuses on the active management of umbilicals connected to small ROVs in order to limit their impact on the system.

The forces transmitted by the cable to the ROV are studied as a function of different parameters using the catenary model and the construction of a finite solids model under Matlab Simulink. A simple method to estimate the torsional stiffness and bending stiffness coefficients of the cable is proposed in order to parameterize these models.

A solution to control the cable distribution by a winch using its instrumentation which is composed of a passive compliance system and a bending sensor is then proposed. This solution is evaluated through simulations of the complete system under Vortex and tank tests of the ROV with its instrumented cable controlled by the reel. The experiments showed the feasibility of the automatic control of the cable at a length adapted to the movements of the ROV thanks to its instrumentation.

Keywords: Underwater robotics, Mechatronic design, Active management of instrumented tether

Translated with www.DeepL.com/Translator (free version)

 

June 2021 EUMR TNA CIRS Experiment

In June, the COSMER laboratory was at CIRS of the University of Girona. The objective of this mission was to use the robot

s and inftrastructures of CIRS to test the algorithms developed at COSMER with a dynamic motion tracking based on our Qualysis motion tracking system.

We acquired nearly 300 sequences in one week and carried out 6 different groups of experiments:

  • Estimation of the hydrodynamic parameters of underwater robots (Mathieu Richier)
  • Development of an intelligent reel (Ornella Tortorici and Cédrice Anthierens)
  • Visual estimation of the shape of an umbilical for the control of a robot rope (Juliette Drupt and Claire Dune)
  • Acoustic estimation of a diver’s position (Bilal Ghader and Claire Dune)
  • Recognition of a diver’s gestures (Bilal Ghader and Claire Dune)
  • Creation of a database for underwater SLAM (Clémentin Boittiaux and Claire Dune)

We thank the CIRS team for their welcome and help in setting up the experiments!

 

 

 

 

June the 24th – PhD Defense Nicolas Gartner

Abstract

Identification of hydrodynamic parameters by simulation with Smoothed Particle Hydrodynamics

This thesis focuses on techniques that allows the simulation of dynamic interactions between an underwater vehicle and the surrounding water. The main objective is to propose a satisfactory solution to be able to test control algorithms and hull shapes for underwater vehicles upstream of the design process. In those cases, it would be interesting to be able to simulate solid and fluid dynamics at the same time. The idea developed in this thesis is to use the Smoothed Particles Hydrodynamics (SPH) technique, which is very recent, and which models the fluid as a set of particles without mesh. In order to validate the simulation results a first study has been performed with a hydrodynamic pendulum. This study allowed the development of an innovative method for estimating the hydrodynamic parameters (friction forces and added mass) which is more robust than previous existing methods when it is necessary to use numerical derivatives of the measured signal. Then, the use of two types of SPH solver : Weakly Compressible SPH and Incompressible SPH, is validated following the validation approach proposed in this thesis. Firstly, the behaviour of the fluid alone is studied, secondly, a hydrostatic case, and finally a dynamic case. The use of two methods for modelling the fluid-solid interaction : the pressure mirroring method and the extrapolation method is studied. The ability to reach a limit velocity due to friction forces is demonstrated. The results of the hydrodynamic parameters estimation from simulation tests are finally discussed. The simulated added mass of the solid approaches reality, but the friction forces currently seem not to correspond to reality. Possible improvements to overcome this problem are proposed.

Keywords : Hydrodynamic parameters, SPH, Numerical method, Interaction, Fluid-solid, Fluid-structure, Incompressible flow, Underwater robotics.

PhD Defense of Maxime Chalvin, July the 9th

Additive manufacturing of tubes by multi-axis robotized wire deposition :
Trajectory generation and optimization

Additive manufacturing through Directed Energy Deposition (DED) enables small batches
of parts to be rapidly manufactured. However, manufacturing trajectories usually used
for the manufacture of overhanging parts require the use of supports, material which
is not useful for the finished part and time consuming. If multi-axis trajectories can be
used to avoid them, they present generally a heterogeneous local inter-layer distance, thus
requiring a variation of the deposition parameters to adapt the layer height ; variation that
can be harmful to the mechanical characteristics of the final part. This thesis first proposes
a constant local inter-layer trajectory generation method for DED additive manufacturing
of tubular parts defined by parametric curves and which can have profile radius variations.
The proposed trajectories have been validated by robotized manufacturing trials of polymer
parts. Since the rotation about a coaxial deposition tool axis has no impact on the deposit,
the use of 6-axis robots offers a redundancy. Using this redundancy, a layer by layer
optimization of the trajectory in the robot space is then proposed. In a constrained robot
configuration, the trajectory optimization allows the manufacturing of parts that cannot
be manufactured in the usual way, and improves the geometrical quality of the parts with
a better repeatability.

TNA EXPERIMENTS IN THE VICOROB’S INFRASTRUCTURES

From the 2nd to the 6th of March, a team of researchers and students of the Université de Toulon have been carrying out experiments at the facilities of the CIRS.

These tests allowed them to collect real data regarding the dynamic behaviour of SPARUS AUV which will be compared with the data from the simulator they are developing in order to improve their predictions.

This action has been possible thanks to the Trans-National Access (TNA) offered by the European project EUMarineRobots. The main objective of the EUMR project is to open up key national and regional marine robotics research infrastructures to all European researchers, from both academia and industry, ensuring their optimal use and joint development to establish a world-class marine robotics integrated infrastructure.

If you are a student, industrial researcher and academic or entrepreneur and you are interested in applying for a TNA to carry out experiments with Girona500 AUV or Sparus II AUV, you have time to apply until the 15th of April 2020!

https://www.eumarinerobots.eu/tna-3rdcall

 

(from https://vicorob.udg.edu/tna-experiments-in-the-vicorobs-infrastructures/)

18 mars 2020 – Youssef Malyani et Lewis Andurand

Thèse de Youssef Malyani

  • Titre: 

Développement d’une recherche mutualisée sur un Référentiel robuste pour le processus de reconception/qualification et réalisation de pièces ou d’ensembles de pièces en Fabrication additive pour la MCO – Naval Group / Maq3D.

  •  Résumé :

 Actuellement, les technologies de fabrication additive permettent de produire des pièces fonctionnelles avec des géométries complexes qui ne peuvent pas être fabriquées par des processus conventionnels. Cependant, la complexité du produit est augmentée et entraîne de nouvelles contraintes dans le processus de fabrication. Par conséquent, ces nouveaux processus conduisent notamment à de nouveaux besoins en méthodes de conception robustes. En effet, cette thèse vise à développer en premier temps un référentiel pour le processus de reconception/qualification de pièces en fabrication additive pour le maintien en condition opérationnelles (MCO), ce référentiel peut être un guide, des réglages tests et des abaques que nous pourrons utiliser en amont lors de la conception d’un produit et qui pourra diminuer les tests de contrôle dans la phase de post production. En plus, il peut nous aider au choix du procédé additif également.

D’autre part, le modèle de calcul le plus utilisé pour la fabrication additive pour déterminer ou doit se trouver la matière est bien évidemment l’optimisation topologique. Ainsi, cette recherche a pour objectif d’élaborer de règles pour l’optimisation topologique de pièces et de systèmes multi-corps avec chaîne cinématique en boucle ouverte et boucles fermées avec des objectifs et des contraintes d’optimisation topologique variées.

———————————————————-

Thèse de Lewis Andurand

  • Titre: 

Développement de stratégies de fabrication pour la réalisation par WAAM de pièces légères obtenues par assemblage de motifs

  • Résumé: 

Les technologies de Fabrication Additive (FA) nommées Wire and Arc Additive Manufacturing (WAAM), utilisent un arc électrique pour fusionner un métal d’apport sous forme de fil. La pièce 3D est ainsi générée par empilement des cordons de soudure aÌ partir de tout type de matériau soudable. Ces procédés sont capables de déposer la matière localement au bon endroit, permettant la réalisation de pièces allégées en supprimant les zones de matière peu contraintes. Ces zones sont rarement supprimées (ou évidées) dans le cas de l’utilisation des autres technologies de fabrication telles que l’usinage car elles sont souvent inaccessibles.

L’opportunité de produire des pièces allégées reste cependant aujourd’hui peu exploitée en fabrication additive de type WAAM. L’une des raisons est que les résultats issus de l’optimisation de forme en Design for Additive Manufacturing ne sont pas fabricables tels quels avec cette technologie, ou au prix d’une productivité très faible.

L’objectif global du projet ANR BeShape (Conception de pièces légères fabriquées par apport de fil et arc électrique) est de proposer et valider une démarche de conception permettant d’obtenir des pièces légères par un assemblage de motifs prédéfinis fabricable par un procédé WAAM, afin de profiter des libertés offertes par ces procédés tout en respectant les contraintes de fabricabilité et les exigences formulées par le concepteur. Le travail de thèse proposé consiste à valider l’hypothèse suivante : si les motifs sont fabricables individuellement, alors il sera possible de les combiner intelligemment pour rendre la pièce fabricable.

Le premier objectif de la thèse est de définir la fabricabilité des motifs. La plage de variation des paramètres géométriques des motifs devra être déterminée de manière à assurer la fabricabilité du motif. Pour cela des essais de paramétrie à l’aide d’un robot de dépôt sont nécessaires. La paramétrie du procédé et la méthode d’obtention des trajectoires, aÌ développer, pourront s’appuyer sur des travaux antérieurs menés au laboratoire COSMER. Les motifs seront ensuite combinés pour obtenir des assemblages de motifs fabricables optimaux vis-à-vis des performances mécaniques souhaitées.

 Le second objectif de la thèse est de proposer une ou des méthodes permettant de fabriquer de tels assemblages. Cette démarche devra aboutir à des stratégies de fabrication optimales vis-à-vis de l’ordonnancement des opérations de dépôt (couche par couche, motif par motif…) et des trajectoires de « liaisons » entre motifs. D’autres aspects pourront être intégrés tels que ceux relatifs à la thermique, les déformations induites et les risques de collisions au sein de la cellule de dépôt ; par exemple en adaptant la trajectoire pour corriger les défauts ou en modifiant l’ordonnancement pour assurer le refroidissement.

L’objectif final est d’obtenir un démonstrateur représentatif d’un cas d’étude industriel du milieu aéronautique.

27 janvier 2020 – Andrew Comport : Visual SLAM

Dr. Andrew Comport, CNRS researcher at the I3S laboratory of the University of the Côte d’Azur, will give a seminar entitled “Localisation and dense mapping for autonomous navigation” on Monday 27 January at 10:30 am at Ifremer (La Seyne Sur Mer, Brégaillon area).

Abstract
In this talk, he will present advanced computer vision approaches for real-time dense location and mapping that have been developed in the context of the European H2020 COMANOID project to control and navigate humanoid robots using dense perception. First, it will show how dense localization and mapping models can be computed in real time to allow precise and robust interaction with 3D scene surfaces. He will present recent advances that integrate temporally, in addition to 3D geometry, the color information contained in images. This will involve defining an inverse super-resolution model for many low-resolution images acquired from different camera poses. In contrast to conventional super-resolution techniques, this is achieved here by taking into account the complete 6D motion transformations as well as the surface structure of the scene.
In a second part, he will present a real-time model for the acquisition of 3D light fields in “High Dynamic Range” (HDR) from several moving images with different exposures (sensor integration periods). In particular, an RGB-D camera will be used as a dynamic light field sensor. Another augmented reality application will be presented that demonstrates the wider use of real-time 3D HDR mapping, virtual light probe synthesis and light source detection to make objects reflective with shadows and transparent with the real-time video stream.

Bio:
Andrew Comport is a CNRS researcher assigned to the I3S laboratory at the University Cote d’Azur. His research focuses on the fields of computer vision, robotics, machine learning and visual servoing. In 2015, he co-founded the start-up PIXMAP, specialized in real-time localization and mapping based on several patents and software. He defended his thesis at INRIA Rennes in 2005 and did a postdoc at INRIA Sophia-Antipolis until 2007. Prior to that, he obtained a double degree in Engineering and Computer Science at Monash University in Australia. He is author of more than 50 international publications among which he won the best paper award at the IEEE/RSJ IROS international conference in 2013. He is currently Associate Editor of the IEEE International Conference on Robotics and Automation (ICRA) and Robotics and Automation Letters (RAL).

Translated with www.DeepL.com/Translator (free version)