Integration of a Passive Exoskeleton and a Robotic Supernumerary Finger for Grasping Compensation in Chronic Stroke Patients: The SoftPro Wearable System

Upper-limb impairments are all-pervasive in Activities of Daily Living (ADLs). As a consequence, people affected by a loss of arm function must endure severe limitations. To compensate for the lack of a functional arm and hand, we developed a wearable system that combines different assistive technologies including sensing, haptics, orthotics and robotics. The result is a device that helps lifting the forearm by means of a passive exoskeleton and improves the grasping ability of the impaired hand by employing a wearable robotic supernumerary finger. A pilot study involving 3 patients, which was conducted to test the capability of the device to assist in performing ADLs, confirmed its usefulness and serves as a first step in the investigation of novel paradigms for robotic assistance

Command Acknowledge through Tactile Feedback Improves the Usability of an EMG-based Interface for the Frontalis Muscle

This work presents a study on the effectiveness of tactile feedback for the acknowledgement of a correct command detection in an EMG-based interface for the frontalis muscle. EMG interfaces are increasingly used in assistive robotics to control robots exploiting the repeatability and robustness of the electromyographic signal. However, in many application a feedback about the correct detection of an input is often missed and the user has to wait for the device motion in order to understand if his/her will has been correctly detected by the system. We demonstrate with a user study involving fifteen subjects, that a simple vibrotactile feedback can reduce the muscular effort and the time needed to execute a sequence of action commanded by an EMG device. As a case study, an EMG interface for the frontalis muscle has been used, however proposed results could be extended to EMG interfaces designed for other muscles, e.g., for prosthesis or exoskeleton control

Conception et évaluation d'actionneurs à embrayages magnétorhéologiques pour la robotique collaborative

La robotique collaborative se démarque de la robotique industrielle par sa sécurité dans le but de travailler en collaboration avec les humains. Toutefois, la majorité des robots collaboratifs sériels reposent sur un actionnement à haut ratio de réduction, ce qui augmente considérablement la masse reflétée à l’effecteur du robot, et donc, nuit à la sécurité. Pour pallier cette masse reflétée et maintenir un seuil minimal de sécurité, les vitesses d’opération sont abaissées, nuisant ainsi directement à la productivité des entreprises. Afin de minimiser la masse reflétée à l’effecteur, les masses des actionneurs ainsi que leur inertie reflétée doivent être minimisés. Les embrayages à fluide magnétorhéologique (MR) maintenus en glissement continus découplent l’inertie provenant de la source de puissance, souvent un moteur et un réducteur, offrant ainsi un actionneur possédant un haut rapport couple-inertie. Toutefois, les embrayages MR, utilisés de façon antagoniste, ajoutent des composantes à l’actionneur ce qui réduit la densité de couple, et donc, augmente la masse reflétée à l’effecteur du robot. Certains actionneurs MR [1–3] ont été développés, mais leur basse densité de couple contrebalance leur faible inertie lorsqu’utilisés comme actionneurs aux articulations de robots collaboratifs sériels. Cette constatation a mené à ma question de recherche : Comment profiter de la faible inertie des actionneurs MR pour maximiser les performances dynamiques des robots collaboratifs sériels? L’objectif de ce projet de recherche vise donc à étudier le potentiel des embrayages MR en robotique collaborative. Pour ce faire, deux architectures MR sont développées et testées expérimentalement. La première architecture consiste en une articulation robotisée modulaire comportant des embrayages MR en glissement continu et possédant un rapport couple/masse et une taille équivalente à l’actionneur d’Universal Robots (UR) de couple égal, mais possédant un rapport couple/inertie 150 fois supérieur. À l’intérieur de l’articulation, deux chaines de puissance (2 moteurs et 2 embrayages MR) indépendantes se rejoignent à la sortie du joint offrant ainsi une redondance et augmentant la densité de couple comparativement à une architecture standard (1 moteur pour 2 embrayages MR). La deuxième architecture étudiée consiste en un actionnement délocalisé du robot où les embrayages MR sont situés à la base du robot et une transmission hydrostatique à membranes déroulantes achemine la puissance aux articulations. Cette architecture a été testée expérimentalement dans un contexte de bras robotisé surnuméraire. Contrairement à l’articulation MR, cette architecture n’offre pas une modularité habituellement recherchée en robotique sérielle, mais offre la possibilité de réduire l’inertie de la structure avec la délocalisation de l’actionnement. Finalement, les deux architectures développées ont été comparées à une architecture standard (haut ratio avec réducteur harmonique) afin de situer le potentiel du MR en robotique collaborative. Cette analyse théorique a démontré que pour un robot collaboratif sériel à 6 degrés de liberté, les architectures MR ont le potentiel d’accélérer 6 et 3 fois plus (respectivement) que le robot standard d’UR, composé d’actionneurs à hauts ratios

Toward wearable supernumerary robotic fingers to compensate missing grasping abilities in hemiparetic upper limb

This paper presents the design, analysis, fabrication, experimental characterization, and evaluation of two prototypes of robotic extra fingers that can be used as grasp compensatory devices for a hemiparetic upper limb. The devices are the results of experimental sessions with chronic stroke patients and consultations with clinical experts. Both devices share a common principle of work, which consists in opposing the device to the paretic hand or wrist so to restrain the motion of an object. They can be used by chronic stroke patients to compensate for grasping in several activities of daily living (ADLs) with a particular focus on bimanual tasks. The robotic extra fingers are designed to be extremely portable and wearable. They can be wrapped as bracelets when not being used, to further reduce the encumbrance. Both devices are intrinsically compliant and driven by a single actuator through a tendon system. The motion of the robotic devices can be controlled using an electromyography-based interface embedded in a cap. The interface allows the user to control the device motion by contracting the frontalis muscle. The performance characteristics of the devices have been measured experimentally and the shape adaptability has been confirmed by grasping various objects with different shapes. We tested the devices through qualitative experiments based on ADLs involving five chronic stroke patients. The prototypes successfully enabled the patients to complete various bimanual tasks. Results show that the proposed robotic devices improve the autonomy of patients in ADLs and allow them to complete tasks that were previously impossible to perform

Activation of the pro-resolving receptor Fpr2 attenuates inflammatory microglial activation

Poster number: P-T099 Theme: Neurodegenerative disorders & ageing Activation of the pro-resolving receptor Fpr2 reverses inflammatory microglial activation Authors: Edward S Wickstead - Life Science & Technology University of Westminster/Queen Mary University of London Inflammation is a major contributor to many neurodegenerative disease (Heneka et al. 2015). Microglia, as the resident immune cells of the brain and spinal cord, provide the first line of immunological defence, but can become deleterious when chronically activated, triggering extensive neuronal damage (Cunningham, 2013). Dampening or even reversing this activation may provide neuronal protection against chronic inflammatory damage. The aim of this study was to determine whether lipopolysaccharide (LPS)-induced inflammation could be abrogated through activation of the receptor Fpr2, known to play an important role in peripheral inflammatory resolution. Immortalised murine microglia (BV2 cell line) were stimulated with LPS (50ng/ml) for 1 hour prior to the treatment with one of two Fpr2 ligands, either Cpd43 or Quin-C1 (both 100nM), and production of nitric oxide (NO), tumour necrosis factor alpha (TNFα) and interleukin-10 (IL-10) were monitored after 24h and 48h. Treatment with either Fpr2 ligand significantly suppressed LPS-induced production of NO or TNFα after both 24h and 48h exposure, moreover Fpr2 ligand treatment significantly enhanced production of IL-10 48h post-LPS treatment. As we have previously shown Fpr2 to be coupled to a number of intracellular signaling pathways (Cooray et al. 2013), we investigated potential signaling responses. Western blot analysis revealed no activation of ERK1/2, but identified a rapid and potent activation of p38 MAP kinase in BV2 microglia following stimulation with Fpr2 ligands. Together, these data indicate the possibility of exploiting immunomodulatory strategies for the treatment of neurological diseases, and highlight in particular the important potential of resolution mechanisms as novel therapeutic targets in neuroinflammation. References Cooray SN et al. (2013). Proc Natl Acad Sci U S A 110: 18232-7. Cunningham C (2013). Glia 61: 71-90. Heneka MT et al. (2015). Lancet Neurol 14: 388-40