Design method for an anthropomorphic hand able to gesture and grasp

This paper presents a numerical method to conceive and design the kinematic model of an anthropomorphic robotic hand used for gesturing and grasping. In literature, there are few numerical methods for the finger placement of human-inspired robotic hands. In particular, there are no numerical methods, for the thumb placement, that aim to improve the hand dexterity and grasping capabilities by keeping the hand design close to the human one. While existing models are usually the result of successive parameter adjustments, the proposed method determines the fingers placements by mean of empirical tests. Moreover, a surgery test and the workspace analysis of the whole hand are used to find the best thumb position and orientation according to the hand kinematics and structure. The result is validated through simulation where it is checked that the hand looks well balanced and that it meets our constraints and needs. The presented method provides a numerical tool which allows the easy computation of finger and thumb geometries and base placements for a human-like dexterous robotic hand.Comment: IEEE International Conference on Robotics and Automation, May 2015, Seattle, United States. IEEE, 2015, Proceeding IEEE International Conference on Robotics and Automatio

Taxation, health system endowment and quality of institutions: a "social" perception across Europe

In this paper we analyze how the health system endowment and the quality of the institutions impact on a change of perception towards taxation. We conduct a sentiment analysis on French, Germans, Italians and Spanish users' tweets to understand if the impact of the current health emergency has modified the tax compliance of the citizens of the four biggest European Countries. We use a difference-in-differences estimation strategy, by comparing the average sentiment of individual tweets regarding taxation in different European NUTS-2 regions, before and after the spread of the Covid-19 pandemic. Our results highlight that in regions characterized by higher levels of health expenditure, people become more prone towards taxation with respect to the period before the widespread of covid-19. In addition, we show how a higher quality of institutions lead to a more positive perception of the same in relative and absolute terms and therefore a greater predisposition for a more progressive tax system

Thermal and fire behavior of a bio-based epoxy/silica hybrid cured with methyl nadic anhydride

Thermosetting polymers have been widely used in many industrial applications as adhesives, coatings and laminated materials, among others. Recently, bisphenol A (BPA) has been banned as raw material for polymeric products, due to its harmful impact on human health. On the other hand, the use of aromatic amines as curing agents confers excellent thermal, mechanical and flame retardant properties to the final product, although they are toxic and subject to governmental restrictions. In this context, sugar-derived diepoxy monomers and anhydrides represent a sustainable greener alternative to BPA and aromatic amines. Herein, we report an “in-situ” sol–gel synthesis, using as precursors tetraethylorthosilicate (TEOS) and aminopropyl triethoxysilane (APTS) to obtain bio-based epoxy/silica composites; in a first step, the APTS was left to react with 2,5-bis[(oxyran-2-ylmethoxy)methyl]furan (BOMF) or diglycidyl ether of bisphenol A (DGEBA) monomers, and silica particles were generated in the epoxy in a second step; both systems were cured with methyl nadic anhydride (MNA). Morphological investigation of the composites through transmission electron microscopy (TEM) demonstrated that the hybrid strategy allows a very fine distribution of silica nanoparticles (at nanometric level) to be achieved within a hybrid network structure for both the diepoxy monomers. Concerning the fire behavior, as assessed in vertical flame spread tests, the use of anhydride curing agent prevented melt dripping phenomena and provided high char-forming character to the bio-based epoxy systems and their phenyl analog. In addition, forced combustion tests showed that the use of anhydride hardener instead of aliphatic polyamine results in a remarkable decrease of heat release rate. An overall decrease of the smoke parameters, which is highly desirable in a context of greater fire safety was observed in the case of BOMF/MNA system. The experimental results suggest that the eect of silica nanoparticles on fire behavior appears to be related to their dispersion degree

Decay of the classical Loschmidt echo in integrable systems

We study both analytically and numerically the decay of fidelity of classical motion for integrable systems. We find that the decay can exhibit two qualitatively different behaviors, namely an algebraic decay, that is due to the perturbation of the shape of the tori, or a ballistic decay, that is associated with perturbing the frequencies of the tori. The type of decay depends on initial conditions and on the shape of the perturbation but, for small enough perturbations, not on its size. We demonstrate numerically this general behavior for the cases of the twist map, the rectangular billiard, and the kicked rotor in the almost integrable regime.Comment: 8 pages, 3 figures, revte

Conception et Contrôle d’une Main Robotique anthropomorphique et dextre

This thesis presents the design and control of a low-cost and lightweight robotic hand for a social humanoid robot. The hand is designed to perform expressive hand gestures and to grasp small and light objects. Its geometry follows anthropometric data. Its kinematics simplifies the human hand structure to reduce the number of actuators while ensuring functional requirements. The hand preserves anthropomorphism by properly placing five fingers on the palm and by ensuring an equilibrated thumb opposability. Its mechanical system results from the compromise between fully-coupled phalanges and self-adaptable fingers in a unique hybrid design. This answers the need for known finger postures while gesturing and for finger adaptation to different object shapes while grasping. The design is based on two distinct actuation systems embodied in parallel within the palm and the fingers. Their coexistence is ensured by a compliant transmission based on elastomer bars. The proposed solution significantly reduces the weightand the size of the hand by using seven low-power actuators for gesturing and a single high-power motor for grasping. The overall system is conceived to be embedded on Romeo, a humanoid robot 1.4 [m] tall produced by Aldebaran. Actuation systems are dimensioned to open and close the fingers in less than1 [s] and to grasp a full soda can. The hand is realized and controlled to ensure safe human-robot interaction and to preserve mechanical integrity. A prototype(ALPHA) is realized to validate the design feasibility and its functional capabilities.Cette thèse présente la conception et la commande d’une main robotique légère et peu onéreuse pour un robot compagnon humanoïde. La main est conçue pour exprimer des émotions à travers des gestes et pour saisir de petits objets légers. Sa géométrie est définie à l’aide de données anthropométriques. Sa cinématique est simplifiée par rapport à la main humaine pour réduire le nombre d’actionneurs tout en respectant ses exigences fonctionnelles. La main préserve son anthropomorphisme grâce aux nombres et au placement de la base des doigts et à une bonne opposabilité du pouce. La mécatronique de la main repose sur un compromis entre des phalanges couplés, qui permettent de bien connaître la posture des doigts pendant les gestes, et des phalanges capable de s’adapter à la forme des objets pendant la saisie, réunis en une conception hybride unique. Ce compromis est rendu possible grâce à deux systèmes d’actionnement distincts placés en parallèle. Leur coexistence est garantie par une transmission compliante basée sur des barres en élastomère. La solution proposée réduit significativement le poids et la taille de la main en utilisant sept actionneurs de faible puissance pour les gestes et un seul moteur puissant pour la saisie. Le système est conçue pour être embarqué sur Romeo, un robot humanoïde de1.4 [m] produit par Aldebaran. Les systèmes d’actionnements sont dimensionnés pour ouvrir et fermer les doigts en moins de 1 [s] et pour saisir une canette pleine de soda. La main est réalisée et contrôlée pour garantir une interaction sûre avec l’homme mais aussi pour protéger l’intégrité de la mécanique. Un prototype (ALPHA) est réalisé pour valider la conception et ses capacités fonctionnelles

Taxation, health system endowment and institutional quality: ‘Social media’ perceptions across Europe

In this paper we analyse how health system endowment and the quality of institutions impact perceptions towards taxation. We conduct a sentiment analysis of Twitter users' tweets to determine whether the impact of the Covid-19 health emergency has modified the attitudes of the citizens towards taxation in the four largest European countries: France, Germany, Italy and Spain. We use a difference-in-differences estimation strategy, comparing the average sentiments of individual tweets regarding taxation in different European NUTS-2 regions, before and after the spread of the Covid-19 pandemic. Our results highlight that in regions characterised by higher health system endowment people adopted more positive attitudes towards taxation with respect to those living in regions with low levels of health system endowment over the period 2019-2020. In addition, we show how higher quality institutions led to more positive perceptions in relative and absolute terms, suggesting a greater predisposition for a more progressive tax system

Hand intended to equip a humanoid robot

A hand intended to equip a humanoid robot, the hand includes a palm and at least one finger extending along a first axis, the hand being capable of picking up an object, the finger comprising a first phalanx linked to the palm by a first motorized pivot link and a second phalanx consecutive tothe first phalanx linked to the first phalanx by a second pivot link. The finger comprises a first mechanism linking the palm to the second phalanx configured such that the rotation of the first phalanx about the second axis causes the second phalanx to rotate about the third axis, and a second mechanism linking the palm to each of the phalanges configured to actuate the finger in such a way that the finger wraps around the object to be picked up, and the second mechanism is configured to deform the first mechanism