Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PhD : selection by topics

Technological challenges >> Factory of the future incl. robotics and non destructive testing
9 proposition(s).

See all positions [+]

Hybrid modeling for the simulation of ultrasonic inspection of laminate composite for the detection of inter-plies damages or weaknesses

Département Imagerie Simulation pour le Contrôle (LIST)

Laboratoire Simulation et Modélisation en Acoustique

01-10-2020

SL-DRT-20-0671

nicolas.leymarie@cea.fr

Factory of the future incl. robotics and non destructive testing (.pdf)

In the framework of the simulation of ultrasonic non-destructive techniques (UT), we consider to design specific simulation tools dedicated to laminate composites. These materials are nowadays widely used in the aeronautical field but show fragility under dynamic stresses such as impacts. Even for low-energy impacts, composite components can be weakened by localized damage, mainly by transverse cracking and delamination. Due to their anisotropic, heterogeneous and multi-layered properties, the development of UT methods for the inspection of such structures is very challenging. Numerical simulation is therefore useful, both for analysis and for the design and optimization of new UT techniques. Based on innovative numerical works, the aim of this study is to propose numerical methods dedicated to the simulation of new UT methods and in particular to the analysis of oblique incidence controls of realistic damage defects. For this, we will rely on existing developments recently done at CEA LIST based on the transient spectral element method, especially by using effective interface conditions to model a realistic delamination or local porosities in inter-plies matrix.

Download the offer (.zip)

Development of a mobile multimodal imager for radiological characterization of complex environments

Département Métrologie Instrumentation et Information (LIST)

Laboratoire Capteurs et Architectures Electroniques

01-10-2020

SL-DRT-20-0744

vincent.schoepff@cea.fr

Factory of the future incl. robotics and non destructive testing (.pdf)

The mitigation of accidental situations such as Chernobyl or Fukushima requires the access to a radiological characterization of environment. Gamma imaging systems provide a solution of interest to address this requirement by allowing the remote visualization of irradiating hot spots through the superimposition of a gamma image onto a visible picture. CEA List is a first rank international actor in the development of gamma cameras for nuclear industry and Homeland Security applications (CARTOGAM, GAMPIX/iPIX and Nanopix gamma cameras). However, may they be based on coded aperture techniques or Compton imaging methods, current imaging systems are required to stay still during the whole acquisition step (from several seconds to minutes), in order to gather sufficient counting statistics for hot spot reconstruction. On the other hand, this reconstruction is achieved through the projection on a two-dimensional space, which makes results uneasy to interpret in case of a complexly crowded and degraded environment. The research project hereby proposed aims at addressing those limitations by allowing the localization of hot spots with a moving imager and implementing the reconstruction of superimposed images in a three-dimensional environment. To this aim, several research paths are proposed and could be coupled into a multimodal mobile imager for the characterization of radiologically degraded areas : the transposition of Compton imaging methods to a mobile referential, allowing the reconstruction by a moving system; the adaptation of tomography reconstruction algorithms for the localization of hot spots with their depth; and the construction of three-dimensional visible images via stereoscopy methods and images structure analysis for reconstructing the environment.

Download the offer (.zip)

Task oriented gripper design methodology for robotic manipulation ? application to pluridigital grippers with flexible joints

Département Intelligence Ambiante et Systèmes Interactifs (LIST)

Laboratoire d'Architecture des Systèmes Robotiques

01-09-2020

SL-DRT-20-0852

florian.gosselin@cea.fr

Factory of the future incl. robotics and non destructive testing (.pdf)

Robots are increasingly visible in our environment, with applications in e.g. fruits and vegetables picking, food packaging and human-robot interactions. All these applications require an efficient solution for grasping and manipulating many different objects. Several approaches have been proposed so far to solve this issue, ranging from double jaw pliers which are very efficient for the grasping of specific tools but cannot deal with other objects nor manipulate them finely, to pluridigital grippers which offer a higher grasping stability and can be reconfigured to grasp various objects. The latter's mechanical complexity and control difficulty however still limit their use in practice to grasping tasks and slow their spread in industry and service robotics. This thesis aims to solve these limitations by combining innovative technological solutions based on the latest advances in flexible structures and 3D printing, distributed sensors and actuators, with task oriented mechanisms synthesis methods, to develop a task oriented design methodology for versatile grasping and dexterous manipulation mechanisms. This methodology will be used for the design and control of novel grippers making use of innovative and adaptive structures that conform automatically to the objects' geometry and can generate sufficiently large in-hand movements. These developments will be validated experimentally on one or several demonstrators.

Download the offer (.zip)

Detection and location of faults in a multiconductor transmission line

Département Architectures Conception et Logiciels Embarqués (LIST-LETI)

Laboratoire Fiabilité et Intégration Capteur

01-09-2019

SL-DRT-20-0890

moussa.kafal@cea.fr

Factory of the future incl. robotics and non destructive testing (.pdf)

The proper functioning of a distribution network depends on the ability to quickly detect the occurrence of faults, such as discharges, short circuits or the penetration of moisture in the cables. If the nature of these defects depends on the application context, the techniques used to detect them depend essentially on the ability to request a cable with test signals, and to monitor the appearance of response signals that would testify to the existence of a modification in the cables. While this approach is clear in the case of standard cables consisting of two conductors, the case of Multiconductor cables remains more complex to deal with. Indeed, applying test signals to a pair of conductors typically causes parasitic excitation of nearby conductors, because of the electromagnetic coupling that connects them. This phenomenon can considerably complicate the interpretation of the results of a test, by creating an ambiguity in the identification of the faulty driver, because several drivers can couple with those actually under test. In this thesis, the coupling will be considered as an opportunity, because it allows to probe a larger number of drivers at the same time. The intrinsic ambiguity of such a proposition can be removed by repeating the tests on several pairs of conductors. It then seems interesting to define optimum choice strategies of drivers to test to cover the largest number of neighboring drivers, without testing all possible combinations. In this sense, this proposal is parsimonious, introducing the concept of effective test surface covered from a pair of conductors. A promising decision strategy for identifying a failing driver is provided by Bayesian tree and graph-based approaches. These tools make it possible to cross the information obtained in order to identify an explanatory model, here the faulty driver. Among the advantages of this approach we can count on their ability to integrate qualitative information, such as the typology of the defect, and to provide a result formulated in terms of probabilities associated with each possible scenario, thus qualifying the interpretation of results and to assess their reliability, unlike purely numerical methods. It will then be necessary to carry out a preparatory work, making it possible to evaluate the probability a priori of observing parasitic signals from a fault on a neighboring conductor. This work will be based on the study of line theory and will provide the link between the physical aspects of Multiconductor propagation and the observables considered during the tests.

Download the offer (.zip)

Study of embedded prognostic strategies in wired networks based on temporal neural networks

Département Architectures Conception et Logiciels Embarqués (LIST-LETI)

Laboratoire Fiabilité et Intégration Capteur

01-09-2020

SL-DRT-20-0891

wafa.benhassen@cea.fr

Factory of the future incl. robotics and non destructive testing (.pdf)

Whatever their fields of application, cables are very often victims of their operating environment. They often face aggressive conditions such as mechanical vibration, heat stress, moisture penetration, etc. These conditions favor the appearance of more or less serious defects ranging from a simple crack in the sheath to a cable break thus causing a malfunction of the system. In this context, the CEA LIST studies methods of diagnosis and prognosis of defects in cable networks based on the reflectometry method. The idea is to inject a test signal into the cable. Whenever it encounters an impedance discontinuity (i.e. a fault), some of its energy is returned to the injection point. The processing of the reflected signal subsequently makes it possible to detect and locate this defect. Despite the maturity of the reflectometry to detect a defect in a cable, it does not allow to determine the causes of the appearance of an incipient defect (ie damage of the shielding, radius of curvature, pinching, etc.) nor to predict its evolution in the future. The work of this thesis aims at developing new prognostic strategies for defects in wired networks. For this, the application of Machine Learning methods such as Artificial Neural Networks (ANN) on data from reflectometry sensors is a promising solution to solve this problem. It is in this context that the works of this thesis are inscribed.

Download the offer (.zip)

Assessing the variability of operators' morphology for assembly tasks using virtual reality

Département Intelligence Ambiante et Systèmes Interactifs (LIST)

Laboratoire de Simulation Interactive

01-10-2020

SL-DRT-20-0920

vincent.weistroffer@cea.fr

Factory of the future incl. robotics and non destructive testing (.pdf)

The aim of the thesis is to develop a tool for the evaluation of the feasability and the ergonomics of a task with operators having a different morphology than an operator performing the task in virtual reality. Two scientific questions will be addressed. The first problem consists in automatically identifying the characteristics of the task to perform (i.e. the important steps, the trajectories and/or the associated efforts), based on a limited number of demonstrations from operators using virtual reality. The second problem consists in transferring the task performance formerly identified to avatars (virtual humans) having different morphologies.

Download the offer (.zip)

Modular device for automated and reliable mapping of indoor installations

Département Métrologie Instrumentation et Information (LIST)

Laboratoire Capteurs et Architectures Electroniques

01-10-2020

SL-DRT-20-1036

maugan.michel@cea.fr

Factory of the future incl. robotics and non destructive testing (.pdf)

The proposed research subject will be focused on the 3D positioning of indoor measurements, where satellite-based positioning (such as the GPS) is ineffective. Different solutions already exist, but are either embedded into a specific equipment, or lack reliability and traceability. SLAM-based algorithms (Simultaneous Localization And Mapping) are of particular interest for these kind of use, allowing for simultaneous reconstruction of the surroundings and real-time localization of the sensor in the reconstructed environment, using low-cost visible cameras, possibly coupled with other sensors (e.g. inertial measurement unit) in order to increase its robustness. The research aims at developing a compact and cross-device mountable device based on these simultaneous localization and mapping solutions that are SLAM algorithms, in order to get a real-time 3D mapping of the surroundings that would include data from any measuring device (including radiological). This module would thus guarantee reliability of the 3D location of the measured value and enable traceability of the resulting mapping in an interoperable format. The device should be embeddable on off-the-shelf hand-held meters (e.g. radiation or contamination meters, gamma-ray spectrometer?) and should thus be both lightweight and compact and result in limited pre- or post-processing.

Download the offer (.zip)

Transportable neutron spectro-imager with high detection sensitivity

Département Métrologie Instrumentation et Information (LIST)

Laboratoire Capteurs et Architectures Electroniques

01-09-2020

SL-DRT-20-1040

clement.lynde@cea.fr

Factory of the future incl. robotics and non destructive testing (.pdf)

Mapping of the radiological situation and waste characterization are important issues for the management of the clean-up and the decommissioning of nuclear facilities. Imaging tools offer a solution of interest for remote detection and localization of irradiating hot spots, by superimposing an image of radioactivity on a visible image. Gamma imaging is the most mature technique at present, due to numerous developments carried out over the last thirty years by several research teams around the world, particularly those at CEA. However, the location and spectrometric measurement of neutron emission is also of great interest to allow the characterization of a wider range of nuclear materials as well as to confirm the presence of particular isotopes, such as plutonium or uranium. Prototypes of neutron spectro-imagers are under development, but significant improvements in terms of sensitivity or portability still need to be made to achieve the performance required to meet the needs of the nuclear industry, particularly those of decommissioning. The proposed thesis topic aims at developing a transportable neutron imager with high sensitivity and capable of measuring the neutron energy spectrum. The developments will rely on the coupling of the two methods of neutron imaging: emission encoding and the use of the elastic scattering phenomenon. This association can be achieved by setting up a measurement system composed of three elements: a coded mask and two pixelated neutron detectors. For reasons of sensitivity and compactness, the pixelated neutron detectors will be based on the coupling of neutron/gamma discriminating plastic scintillators with an array of silicon photomultipliers. The energy signature of the neutrons may be obtained by a spatial and kinetic analysis of the interactions.

Download the offer (.zip)

New generation of coded aperture collimators for imaging ionising radiations

Département Métrologie Instrumentation et Information (LIST)

Laboratoire Capteurs et Architectures Electroniques

01-10-2020

SL-DRT-20-1056

vincent.schoepff@cea.fr

Factory of the future incl. robotics and non destructive testing (.pdf)

The localization of radioactive hot spots is a major issue for the initial characterization of an installation to be decommissioned. International research teams, in order to detect, localize and quantify the emitted radiations of radiological materials, developed specific tools for a long time. Miniaturized gamma imaging systems, equipped with coded masks (multi-pinhole collimators arranged according to a specific mathematical pattern) and pixelated semi-conductor detectors have been developed over the past twenty years, including by CEA List and CEA Irfu who are proposing the research project. Nevertheless, due to their nature, imaging high-energy radiations (from 10 keV to 2 MeV) still is challenging, and we propose to address those challenges in the frame of this subject. Aiming at developing a new generation of large field of view coded masks, the research program will lead to prototypes manufactured by sophisticated techniques of machining and/or by 3D metal printing processes, allowing the optimization of performances in the field of gamma and neutron imaging. Expected research paths will focus on two different encoding methods : non linear spatial encoding with 3D masks (hemispherical, conical or polyhedral) and temporal encoding (setting the mask in motion to allow temporal modulation of signals, a route generally considered risky in systems and rarely studied). The two encoding approaches will be studied independently and successively then coupled, in order to optimize performance.

Download the offer (.zip)

See all positions