Modélisation et commande des systèmes de manipulation sans contact. : Vers l'amélioration du diagnostic en endoscopie digestive.

Diagnostic techniques currently used in gastrointestinal endoscopy do not allow a completeand accurate observation of the small bowel. Endoscopic capsules were designed to solvethis problem, but the doctor cannot control their movement once they are swallowed bypatients. In that context, the work developed in this thesis focuses on the use of magneticfields to manipulate an object (such as a capsule) without contact, on a large workspace.For this, we study magnetic systems with mobile electromagnets. We study first how tomodel the magnetic field created by an electromagnet. We develop an analytical modeltaking into account the ferromagnetic core of electromagnets. Then, we study a genericsystem composed of n electromagnets which can move throughout space. We develop amodel of the system, integrating the mobility of each of the electromagnets. This modelis then linearized, allowing us to introduce a linearizing control. This command allowsindependent management of the movement of each of the electromagnets, and the currentflowing in it. Finally, the model and the command are tested in simulation and on anexperimental device.Keywords: Magnetism,Les techniques de diagnostic actuellement utilisées en endoscopie digestive ne permettentpas une observation complète et précise de l’intestin grêle. Les capsules endoscopiquestentent de répondre à cette problématique, mais le médecin n’a aucune maîtrise de leurdéplacement une fois qu’elles sont avalées par les patients. Dans ce contexte, les travauxdéveloppés dans cette thèse portent sur l’utilisation des champs magnétiques afin demanipuler un objet (comme une capsule) sans contact sur un large espace de travail. Pourcela, nous étudions les systèmes de manipulation magnétique à électroaimants mobiles.Nous étudions dans un premier temps la manière de modéliser le champ magnétiquecréé par un électroaimant. Nous développons un modèle hybride (analytique recalé surdes mesures) prenant en compte le noyau ferromagnétique des électroaimants. Dans unsecond temps, nous nous intéressons à un système générique de manipulation magnétique,composé de n électroaimants pouvant se déplacer dans tout l’espace. Nous développons unmodèle de ce système, en intégrant les mobilités de chacun des électroaimants. Ce modèleest ensuite linéarisé, ce qui nous permet d’introduire une commande linéarisante. Cettecommande permet une gestion indépendante du déplacement de chacun des électroaimants,ainsi que du courant qui les traverse. Enfin, les développement théoriques sont testés ensimulation et sur un dispositif expérimental

Key Features of the Coupled Hand-operated Balanced Manipulator (HOBM) and Lightweight Robot (LWR)

International audienceThe paper deals with coupled systems including hand-operated balanced manipulators and lightweight robots. The aim of such a cooperation is to displace heavy payloads with less powerful robots. In other term, in the coupled system for handling of heavy payloads by a HOBM an operator is replaced by a LWR. The advantages of the coupled HOBM and LWR are disclosed and the optimal design of the cooperative workspace is discussed. Behavior of the coupled system in a static mode when the velocities the HOBM are limited does not present any special problems. In this mode, the inertial forces are significantly lower than the gravitational one. The payload is completely balanced by the HOBM and the LWR assumes the prescribed displacements with low load. However, in a dynamic mode, the HOBM with massive links creates additional loads on the LWR, which can be significant. The present study considers a method for determination of inertia effects of the HOBM on the LWR. The given numerical simulations show the significant increasing of the input torques due to the inertia forces of the HOBM. Behavior of the HOBM with cable lift and the LWR is also examined

Magnetic manipulation with several mobile coils towards gastrointestinal capsular endoscopy.

Traditional techniques of endoscopy based on flexible endoscopes are fairly reliable but poorly tolerated by patients and do not give access to the small bowel. It has been demonstrated that magnetic fields are usable for manipulating an untethered magnet, either using fixed coils or mobile permanent magnets.We introduce a novel approach for magnetic manipulation and present the preliminary results obtained by simulating a planar manipulation system including multiple mobile coils

Geometric analysis of the singularities of a magnetic manipulation system with several mobile coils.

International audienceIt has been demonstrated that magnetic fields are relevant for manipulating an untethered magnet, either using fixed coils or mobile permanent magnets. This paper shows however, that any magnetic manipulation method is prone to singular configurations and that the simple numerical analysis of the rank of the "manipulation matrix" is not enough to detect them. Alternatively, we propose a geometrical analysis to interpret and detect the singularities as well as to decide on the acceptability of a reference trajectory. Then, we present results obtained by simulating a planar manipulation system including a multiple mobile coils and a Helmholtz like set-up

Advocacy for Multi Mobile Coil Magnetic Manipulation in Active Digestive Endoscopy.

International audienceTraditional techniques of endoscopy based on flexible endoscopes are fairly reliable but poorly tolerated by patients and do not give access to the small bowel. Magnetic fields have been shown usable for manipulating endoscopic capsules, either using static coils with varying currents or mobile permanent magnets. In this short paper, we propose a novel approach which combines electromagnetic and kinematic effects and outline our research

Modeling and contrôl of contractless magnetic manipulation systems : Towards improving diagnosis in digestive endoscopy

Les techniques de diagnostic actuellement utilisées en endoscopie digestive ne permettentpas une observation complète et précise de l’intestin grêle. Les capsules endoscopiquestentent de répondre à cette problématique, mais le médecin n’a aucune maîtrise de leurdéplacement une fois qu’elles sont avalées par les patients. Dans ce contexte, les travauxdéveloppés dans cette thèse portent sur l’utilisation des champs magnétiques afin demanipuler un objet (comme une capsule) sans contact sur un large espace de travail. Pourcela, nous étudions les systèmes de manipulation magnétique à électroaimants mobiles.Nous étudions dans un premier temps la manière de modéliser le champ magnétiquecréé par un électroaimant. Nous développons un modèle hybride (analytique recalé surdes mesures) prenant en compte le noyau ferromagnétique des électroaimants. Dans unsecond temps, nous nous intéressons à un système générique de manipulation magnétique,composé de n électroaimants pouvant se déplacer dans tout l’espace. Nous développons unmodèle de ce système, en intégrant les mobilités de chacun des électroaimants. Ce modèleest ensuite linéarisé, ce qui nous permet d’introduire une commande linéarisante. Cettecommande permet une gestion indépendante du déplacement de chacun des électroaimants,ainsi que du courant qui les traverse. Enfin, les développement théoriques sont testés ensimulation et sur un dispositif expérimental.Diagnostic techniques currently used in gastrointestinal endoscopy do not allow a completeand accurate observation of the small bowel. Endoscopic capsules were designed to solvethis problem, but the doctor cannot control their movement once they are swallowed bypatients. In that context, the work developed in this thesis focuses on the use of magneticfields to manipulate an object (such as a capsule) without contact, on a large workspace.For this, we study magnetic systems with mobile electromagnets. We study first how tomodel the magnetic field created by an electromagnet. We develop an analytical modeltaking into account the ferromagnetic core of electromagnets. Then, we study a genericsystem composed of n electromagnets which can move throughout space. We develop amodel of the system, integrating the mobility of each of the electromagnets. This modelis then linearized, allowing us to introduce a linearizing control. This command allowsindependent management of the movement of each of the electromagnets, and the currentflowing in it. Finally, the model and the command are tested in simulation and on anexperimental device.Keywords: Magnetism

Hybrid electromagnet model for multiple mobile coil magnetic manipulation.

International audienceIn gastroenterology, endoscopic capsules have demonstrated their usefulness for diagnosis in the small bowel.However, they also show limitations due to the impossibility to control their progress in the small bowel. Magnetic actuation is often considered to control these capsules, but current systems are very bulky and some have stability concerns. To improve the manipulability of the capsule and to reduce the size of the magnetic system, it is interesting to consider a system composed of mobile electromagnets having a ferromagnetic core. These electromagnets allow to create large efforts at lower currents, but produce a magnetic field highly non-linear. This paper proposes a hybrid model (analytical adjusted on measures) to compute the magnetic field created by the electromagnets, and discusses the usefulness of this model

Key Features of the Coupled Hand-operated Balanced Manipulator (HOBM) and Lightweight Robot (LWR)

International audienceThe paper deals with coupled systems including hand-operated balanced manipulators and lightweight robots. The aim of such a cooperation is to displace heavy payloads with less powerful robots. In other term, in the coupled system for handling of heavy payloads by a HOBM an operator is replaced by a LWR. The advantages of the coupled HOBM and LWR are disclosed and the optimal design of the cooperative workspace is discussed. Behavior of the coupled system in a static mode when the velocities the HOBM are limited does not present any special problems. In this mode, the inertial forces are significantly lower than the gravitational one. The payload is completely balanced by the HOBM and the LWR assumes the prescribed displacements with low load. However, in a dynamic mode, the HOBM with massive links creates additional loads on the LWR, which can be significant. The present study considers a method for determination of inertia effects of the HOBM on the LWR. The given numerical simulations show the significant increasing of the input torques due to the inertia forces of the HOBM. Behavior of the HOBM with cable lift and the LWR is also examined

Water vapor observation at 42 m height above ground at Dome C, East Antarctic plateau (2018-2020)

The data set provides 3 years of almost continuous observation of water vapor in the air at 42m height on the high antarctic plateau, 123° 21' E, 75° 06' S, 3233 m above sea level. Each data is an average over the previous ½ hour. The water vapor content is measured in a heated air flow to avoid that supersaturated air at ambient temperature deposits excess moisture (above 100% with respect to ice) before reaching the humidity sensor. In fact, many reports correspond to significant supersaturation (see references provided). HMP155 thermohygrometers are used, which for the hygrometer natively report relative humidity with respect to liquid water even below 0°C. This is the variable provided in the data set, along with temperature in the heated air flow and ambient temperature. There are several conversion formulae in the literature to convert to e.g. partial pressure and relative humidity with respect to ice. As there is no clear consensus on which should be preferred in the range of temperatures at Dome C, the user is left to carry our her/his own conversions