Robotic Manipulator for Positioning a Magnetic Actuator Dedicated to Drug Delivery in the Cochlea

International audienceThe actuators dedicated to micrometric applications are known for their precision but also for their restricted workspace. The use of a robotic manipulator as a carrier makes it possible to considerably increase this workspace. In this paper, we present a novel robotic system specially designed for positioning a magnetic actuator based on permanent magnets, used as an end-effector of the robot for steering magnetic microrobot throughout the cochlea. Using the classical mathematical tools of serial robotics, we determined the direct and inverse kinematic models of the manipulator, thus defining a reference trajectory to move the microrobot on a space as small as possible and take account of the geometrical specifications based on medical needs. A prototype has been realized with a 3D printer to experimentally validate the numerical results. In addition, the mechanical considerations for the construction of the prototype are presented

Nonlinear Control and Synchronization with Time Delays of Multiagent Robotic Systems

We investigate the cooperative control and global asymptotic synchronization Lagrangian system groups, such as industrial robots. The proposed control approach works to accomplish multirobot systems synchronization under an undirected connected communication topology. The control strategy is to synchronize each robot in position and velocity to others robots in the network with respect to the common desired trajectory. The cooperative robot network only requires local neighbor-to-neighbor information exchange between manipulators and does not assume the existence of an explicit leader in the team. It is assumed that network robots have the same number of joints and equivalent joint work spaces. A combination of the lyapunov-based technique and the cross-coupling method has been used to establish the multirobot system asymptotic stability. The developed control combines trajectory tracking and coordination algorithms. To address the time-delay problem in the cooperative network communication, the suggested synchronization control law is shown to synchronize multiple robots as well as to track given trajectory, taking into account the presence of the time delay. To this end, Krasovskii functional method has been used to deal with the delay-dependent stability problem

Spherical wrist dimensional synthesis adapted for tool-guidance medical robots

The objective of this article is to present the dimensional synthesis of serial or parallel spherical wrists, an important step in the design process of medical robots. This step is carried out to obtain optimal dimensions of tool-guidance medical robots. In this goal, we have first studied the specifications of two robots with different medical applications: one for minimally invasive surgery and one for tele-echography examination. Then, we have established that the medical needs expressed by the doctor were very different but the specifications in robotic terms have a lot of common points (kinematics, workspace, bulkiness). Both types of robots need a mobility of three rotations around a fixed point (trocar incision or probe contact point on patient’s skin). So a spherical wrist structure is adapted to their needs. An important constraint related to medical applications is that the robot must be compact to not obstruct the robot environment (medical personnel or patient). We perform dimensional synthesis allowing determination of dimensions of the mechanism for a spherical wrist, serial and parallel for a tele-echography robot, and serial for the minimally invasive surgery robot. We used multi-criteria optimization methods minimising a cost function to obtain both good kinematic performance and compactness for the structure. The difficulty and the difference between the presented studies are in the choice of design criteria describing the performance and the constraints of the robot. These parameters must faithfully represent the specifications of the robot so that its performance can respond to the medical requirements. We show, here, the different methods used for the chosen kinematic structure and the medical application. These studies lead to prototypes which are validated by medical experiments. This process of dimensional synthesis will be applied to other medical applications with different sets of specified constraints

Campagne océanographique FLUPAC à bord du N.O. l'ATALANTE 23 septembre au 29 octobre 1994. Recueil des données. Tome 1 : météo, courantologie, hydrologie, données de surface

La campagne FLUPAC du N.O. L'Atalante, qui s'est déroulée du 23 septembre au 29 octobre 1994, s'est placée dans le cadre du programme international JGOFS (JOINT GLOBAL OCEAN FLUX STUDY). Elle a comporté deux radiales et deux stations équatoriales de 6-7 jours. La première radiale, le long de 165°E, a parcouru la zone comprise entre 20°S et 6°N. La seconde s'est déroulée le long de l'équateur entre 167°E et 150°W. Les deux stations de longue durée ont eu lieu à O°-167°E et 0°-150°W. Elles ont été l'occasion d'études détaillées des flux impliqués dans le cycle du carbone de la couche superficielle (0-500 m). Le premier tome du recueil de données présente des résultats, sous forme de graphiques et de tableaux, des paramètres enregistrés en continu et de ceux de la sonde CTD. Les paramètres chimiques, la chlorophylle "a" et les observations en cytomètrie de flux obtenus sur l'eau de la "rosette" couplée à la sonde CTD, sont également présentés. (Résumé d'auteur

Testing Alternative Theories of Gravity using LISA

We investigate the possible bounds which could be placed on alternative theories of gravity using gravitational wave detection from inspiralling compact binaries with the proposed LISA space interferometer. Specifically, we estimate lower bounds on the coupling parameter \omega of scalar-tensor theories of the Brans-Dicke type and on the Compton wavelength of the graviton \lambda_g in hypothetical massive graviton theories. In these theories, modifications of the gravitational radiation damping formulae or of the propagation of the waves translate into a change in the phase evolution of the observed gravitational waveform. We obtain the bounds through the technique of matched filtering, employing the LISA Sensitivity Curve Generator (SCG), available online. For a neutron star inspiralling into a 10^3 M_sun black hole in the Virgo Cluster, in a two-year integration, we find a lower bound \omega > 3 * 10^5. For lower-mass black holes, the bound could be as large as 2 * 10^6. The bound is independent of LISA arm length, but is inversely proportional to the LISA position noise error. Lower bounds on the graviton Compton wavelength ranging from 10^15 km to 5 * 10^16 km can be obtained from one-year observations of massive binary black hole inspirals at cosmological distances (3 Gpc), for masses ranging from 10^4 to 10^7 M_sun. For the highest-mass systems (10^7 M_sun), the bound is proportional to (LISA arm length)^{1/2} and to (LISA acceleration noise)^{-1/2}. For the others, the bound is independent of these parameters because of the dominance of white-dwarf confusion noise in the relevant part of the frequency spectrum. These bounds improve and extend earlier work which used analytic formulae for the noise curves.Comment: 16 pages, 9 figures, submitted to Classical & Quantum Gravit

The Confrontation between General Relativity and Experiment

The status of experimental tests of general relativity and of theoretical frameworks for analysing them is reviewed. Einstein's equivalence principle (EEP) is well supported by experiments such as the Eotvos experiment, tests of special relativity, and the gravitational redshift experiment. Future tests of EEP and of the inverse square law are searching for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, and the Nordtvedt effect in lunar motion. Gravitational-wave damping has been detected in an amount that agrees with general relativity to better than half a percent using the Hulse-Taylor binary pulsar, and other binary pulsar systems have yielded other tests, especially of strong-field effects. When direct observation of gravitational radiation from astrophysical sources begins, new tests of general relativity will be possible.Comment: 89 pages, 8 figures; an update of the Living Review article originally published in 2001; final published version incorporating referees' suggestion

Proposition d'une architecture multifonctions pour l'autonomie globale des robots

Le travail présenté dans ce mémoire propose une solution pour l amélioration de l autonomie globale d un système robotisé. Celle-ci est l association d autonomies de deux natures, une liée à une architecture structurelle et l autre liée à l architecture de commande. Après une étude des solutions cinématiques existantes en robotique mobile à roues, il est montré comment on peut apporter un maximum d autonomie de déplacement à un robot mobile en se focalisant sur son architecture structurelle. Le résultat obtenu est un robot omnidirectionnel. Cet aspect ne représente qu une partie de l amélioration de l autonomie. En effet, le concept d autonomie globale consiste à compléter le travail sur l architecture structurelle par une amélioration de l architecture de commande. Fait alors suite une étude bibliographique des architectures de commandes existantes allant jusqu à la prise en compte des architectures logicielles. Une solution modulaire, hiérarchique, multi-niveaux permettant de représenter l ensemble des niveaux d autonomie attendus pour un robot autonome est développée. Elle a comme spécificité l intégration avancée de la télé-opération. Ceci permet d augmenter le nombre de modes de fonctionnements disponibles et aussi de pouvoir construire progressivement l architecture de commande. Différentes applications ont été réalisées sur la base de cette architecture : la diversité des robots utilisés (robot omnidirectionnel, robot mobile embarquant des télémètres, robot médical porte-sonde) montre l aspect générique donné à cette architectureORLEANS-BU Sciences (452342104) / SudocSudocFranceF

Contribution à une conception appropriée de robots médicaux (vers une démarche mécatronique)

Dans cette thèse, nous apportons la contribution à la conception de robots médicaux, en proposant une démarche de conception simultanée de la structure mécanique du robot. Par opposition à une vision séquentielle naturelle de la conception, la formalisation du processus créatif permet une simultanéité, ouvrant la voie à des structures innovantes dédiées : en robotique médicale, faible masse et faible compacité de la structure mécanique sont souvent recherchées. A partir d un descriptif de démarches existantes, nous effectuons la conception d un robot de télé-échographie et d un robot de chirurgie mini-invasive. Pour les deux applications, de fortes contraintes sont présentes. En télé-échographie, la portabilité est très recherchée, requérant une faible compacité. Pour la chirurgie mini-invasive, les moto-réducteurs du robot in vivo doivent être dimensionnés au plus juste. Ici, nous avons formalisé l amélioration de la compacité d une structure parallèle pour la télé-échographie. Les résultats montrent une amélioration de la compacité de l ordre de 5%. Dans le même esprit, nous avons formalisé la synthèse dimensionnelle de deux robots 2R-R-R de chirurgie mini-invasive in vivo. Nous réalisons l optimisation simultanée entre le dimensionnement des moto-réducteurs et des longueurs des corps pour tendre vers une simultanéité totale du processus créatif, ce qui nous permet d améliorer les performances en termes de force et vitesse à l effecteur. Ces expériences de conception montrent les limites à une simultanéité stricte. Nous indiquons le besoin d adapter outils et méthodes de conception mécatronique pour une simultanéité en conception robotique tenant compte de l aspect imparfait du processus créatif.In this thesis, we propose a contribution to the design of medical robots, by offering a concurrent design or simultaneous approach. As opposed to a natural sequential view of the design process, the formalization of the creative process allows simultaneity, paving the way for innovative structures, dedicated: in the medical robotic field, low mass and low compactness of the mechanical structure are often sought. From a description of existing approaches, we design a tele-ultrasound robot and a minimally invasive surgery robot. For both applications, high physical integration is required. For tele-ultrasound robots, portability is highly sought, requiring low compactness. For minimally invasive surgery, geared motors of the in vivo robot must be sized correctly. Here, we formalized the improvement of compactness of an existing parallel structure for remote ultrasound application. The results show an improvement of compactness of around 5%. In the same way, we formalize the dimensional synthesis of two robots 2R-R-R for in vivo minimally invasive surgery. The results show the under-sizing of some actuators. We perform simultaneous optimization between the design of geared motors and lengths of the body of a robot 2R-RR, tendering towards full simultaneity of the creative process, allowing to improve minimal force and velocity at the end-effector of the robot. These experiments of design show limits to a strict simultaneity. We indicate the need to adapt the tools and methods of mechatronic design for simultaneous robotics design, taking into account the imperfect aspect of the creative process.ORLEANS-SCD-Bib. electronique (452349901) / SudocSudocFranceF

Démarche de conception de robots médicaux (application à un robot de télé-échographie)

A partir de la conception d un robot pour une application médicale particulière de télé-échographie, une démarche de conception générique de robots médicaux est proposée. L étude se décompose en deux phases : la synthèse topologique et la synthèse dimensionnelle. La première est effectuée pour toutes applications médicales à partir de connaissances capitalisées dans un catalogue de robots médicaux réalisé au préalable. La synthèse dimensionnelle est établie pour un robot de télé-échographie. Une nouvelle structure cinématique de poignet sphérique série permettant de rejeter la singularité aux frontières de l espace de travail est proposée. Après avoir réalisé une analyse cinématique validant le concept, plusieurs optimisations multi-critères sont effectuées selon des critères de performances cinématiques (manipulabilité, dextérité) et d encombrement (compacité). Une comparaison de l influence des indices de performance sur l optimisation est réalisée. Le concept pour l application de télé-échographie choisi et dimensionné, une démarche de conception préliminaire à l aide de l outil CAO est présentée. Une phase de conception collaborative avec des designers est menée afin d améliorer l ergonomie, la compacité et l esthétique du robot. L association des étapes de synthèses et de conception préliminaire a conduit à la proposition d une démarche de conception de robots médicaux.From the design of a tele-echography robot for a specific medical application, a generic methodology for medical robots design is proposed. The study is presented in two parts: a topological synthesis and a dimensional one. The first is made for all medical applications, from a medical robots catalogue built beforehand. The second synthesis is established for a tele-echography robot. A new spherical kinematic structure permitting to reject singularities to the boundaries of the workspace is proposed. After having validated this concept from a kinematic point of view, several multi-criteria optimisations are realised according to kinematic indices (manipulability, dexterity) and bulkiness (compactness). A comparison of indices influence on optimisations is carried out. The concept for teleechography robot chosen and dimensioned, a process of embodiment design with CAD tool is presented. A collaborative design phase with designers is led to improve ergonomics, compactness and aesthetic of the robot. The association of synthesis steps and embodiment design lead to propose a process of medical robots design.ORLEANS-SCD-Bib. electronique (452349901) / SudocSudocFranceF

Geometric Approach for Inverse Kinematics of the FANUC CRX Collaborative Robot

Because they are safe and easy to use, collaborative robots are revolutionizing many sectors, including industry, medicine, and agriculture. Controlling their dynamics, movements, and postures are key points in this evolution. Inverse kinematics is then crucial for robot motion planning. In 6R serial robots, achieving a desired pose is possible with different joint combinations. In this paper, our focus lies in studying forward and, mainly, inverse kinematics of the FANUC CRX-10iA cobot, a 6R cobotic arm with a non-spherical wrist. Its specific structural parameters implies that no analytical solutions exist except for some particular situations. FANUC does not provide the complete set of inverse kinematic solutions, even when 16 solutions are possible, only 8 of them are provided in Roboguide software. Furthermore, the existing literature on joints-to-workspace mapping for CRX cobots is currently very limited. It either lacks or provides partial or inconsistent inverse kinematics analysis. We present and detail a novel fully geometric method for numerically solving inverse kinematics meeting the requirement of high precision and a fast response. This approach provides both the exact number of inverse kinematics solutions and the sets of joint angles even for singular configuration. Its effectiveness was verified through simulations using the Roboguide Software and experimentation on the actual CRX-10iA cobot. Several examples (8, 12, or 16 inverse kinematic solutions) have enabled us to validate and prove the robustness and reliability of this geometric approach