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!

 

 

 

 

07-13-2021 Frederik Wulle Seminar

We will receive Mr Frederik Wulle, PhD student at the University of Stuttgart in Germany, during the first two weeks of July (from 5 to 16).

He will present his institution and his research activities during a laboratory seminar that will take place on Tuesday 13 July at 2 pm in room M005:

ISW / Institute for Control Engineering of Machine Tools and Manufacturing Units:

  • Short introduction of the University of Stuttgart
  • Overview of the institute and research areas
  • Selected projects of our institute

For more information on its activities: https://www.isw.uni-stuttgart.de/en/institute/team/Wulle/

This video link will allow you to follow him remotely: https://zoom.us/j/99

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

06-03-21 Maxime Chalvin and Alexis Claude Seminar

Alexis CLAUDE and Maxime CHALVIN will present their research work during the 

SEMINAR on June 3, 2021 

starting at 1:30 pm 
This seminar will be held in M141 and on zoom. 
Participate to the Zoom meeting
https://us04web.zoom.us/j/71569589921?pwd=OGV2WVBtUld6Vm1nRmdYa2dTcUV1Zz09

Meeting ID: 715 6958 9921
Secret code : bHJ4F3

 

Thermal analysis of manufacturing strategies for cylindrical parts with thick walls
by WAAM additive manufacturing
Alexis CLAUDE

Abstract: The seminar will focus on the development of additive manufacturing strategies for thick-walled cylinders obtained by WAAM (arc welding). The material used for the study is an aluminum alloy 5183 deposited with a robotic CMT source.

In order to do so, it was necessary to set up an in-situ temperature measurement system (pyrometer) as well as an adapted interlayer temperature management strategy. This process is indeed crucial in order to guarantee the manufacturability and the expected geometry.

In order to reach an optimal manufacturing method for thick-walled cylinders, several filling strategies are studied: the strategy of juxtaposition of beads, the strategy of periodic advance pattern (sine type) and finally the strategy of periodic pattern with contours. The work consisted firstly in defining the parametrization of the pattern in simplified configuration; then in applying it to the final geometry sought.

For the moment, the work carried out mainly concerns the juxtaposition strategy. Following difficulties encountered when juxtaposing strands with a constant inter-strand distance, an alternative strategy has been developed and implemented.

 

Layer-by-layer temperature management for WAAM additive manufacturing

Maxime CHALVIN(a)(b)*, Alexis CLAUDE(b)(c), Sébastien CAMPOCASSO(b), Vincent HUGEL(b)
(a) SEGULA Technologies, 19 rue d’Arras, 92000 Nanterre
(b) University of Toulon, COSMER, Toulon, France
(c) University of Toulon, MAQ3D Platform, Toulon, France
* Correspondent : maxime.chalvin@univ-tln.fr

Abstract: WAAM additive manufacturing, based on a wire-arc welding process, allows the production of large metal blanks at interesting economic conditions for small series. However, the quality of the parts depends strongly on the temperature management during the manufacturing process. Indeed, the deposition method implies a significant heat transfer to the part and it may be necessary to stop the deposition to allow its cooling. In order to determine the influence of heat on the geometrical quality of thin-walled parts of revolution, a method of in-situ temperature measurement using a pyrometer and a strategy of inter-layer temperature management is proposed. The inter-layer temperature measurement and management methods are applied to the fabrication of thin-walled cylinders of different nominal diameters. The geometrical control of the latter allows to evaluate the impact of the diameter on the geometrical quality at iso-conditions of manufacture. The material studied is an aluminum alloy 5183 deposited with a robotic CMT source. The proposed method of measuring and managing the inter-layer temperature allows to guarantee the deposition of each layer under similar thermal conditions, in order to control the manufacturing operating conditions.

Key words: Additive manufacturing, WAAM, Temperature, Thin walls.

 

04-22-2021 Thierry Champion Seminar

 

Thierry CHAMPION will present a part of his research work during the 

SEMINAR on April 22, 2021 

from 1:30 pm 
which will take place in room M005.

Video link for those who cannot attend: https://zoom.us/j/96942693591?pwd=a2dEUktkNFI2K2NYQ1E0a0w2VDN1dz09

Title: Convergence of penalization methods in convex optimization

Abstract: My objective in this talk is to introduce the classical penalty methods in convex optimization (which includes linear programming) and the study of their convergence, both primal and dual. I will discuss both the theoretical point of view (without going into too specialized mathematical considerations) and the practical implementation.