Design, implementation and control of a deformable manipulator robot based on a compliant spine

International audienceThis paper presents the conception, the numerical modeling and the control of a dexterous, deformable manipulator bio-inspired by the skeletal spine found in vertebrate animals. Through the implementation of this new manipulator, we show a methodology based on numerical models and simulations, that goes from design to control of continuum and soft robots. The manipulator is modeled using Finite Element Method (FEM), using a set of beam elements that reproduce the lattice structure of the robot. The model is computed and inverted in real-time using optimisation methods. A closed-loop control strategy is implemented to account for the disparities between the model and the robot. This control strategy allows for accurate positioning, not only of the tip of the manipulator, but also the positioning of selected middle points along its backbone. In a scenario where the robot is piloted by a human operator, the command of the robot is enhanced by a haptic loop that renders the boundaries of its task space as well as the contact with its environment. The experimental validation of the model and control strategies is also presented in the form of an inspection task use case

Aves Marinas Anidando en Islas de la Sonda de Campeche

Esta zona arrecifal, la más norteña del Golfo de México mexicano alberga las mayores colonias de anidación de aves marinas de la región. El último censo se realizó en 1986. En la zona se practica la pesca, turismo y explotación petrolífera, que potencialmente constituyen un riesgo para la biodiversidad del arrecife. La zona está pobremente estudiada y es importante obtener información sobre sus recursos para manejarlos adecuadamente. Nuestro objetivo es actualizar la información sobre las especies de aves marinas que anidan en las islas del Parque Nacional Arrecife Alacranes y Cayo Arenas. Se visitaron 6 islas a mediados de marzo de 2009 y se hicieron, básicamente, conteos directos de nidos. El total encontrado fue: I.Perez: 139,116 nidos para Sterna fuscata, 1,039 para Anous stolidus; I.Muertos: 827 nidos de Sula dactylatra, 10 de S.sula y 50 de Fregata magnificens; I.Pájaros: 64 nidos de S.dactylatra; I.Chica: 22 nidos de S.dactylatra; I.Desterrada: 82 nidos de S.leucogaster; C.Arenas: 120 nidos de S.dactylatra. . En I.Pérez encontramos 10 veces más nidos de S.fuscata que el ultimo censo publicado, al igual que de S.dactylatra, tanto en I.Pájaros como en I.Chica, en esta última no se habían reportado nidos de esta especie en el último estudio. En I.Muertos (Desertora) encontramos entre el 25 y 30% de los nidos de S.dactylatra y F.magnificens que los encontrados en el último censo, pero se encontraron nidos de S. sula, que no se habían reportado en ése. El censo de 1986 se realizó en una época del año diferente al nuestro (enero y julio) lo cual puede explicar las diferencias en las poblaciones encontradas. Otro factor importante puede ser la protección que actualmente se lleva a cabo en la zona por ser área protegida

Autonomy and sustainability in participatory video practice with indigenous communities. La Marabunta Filmadora as a case-study

El presente artículo analiza dos dinámicas clave en las experiencias de vídeo participativo con colectivos indígenas: 1) la autonomía de los grupos participantes, que aparece como el horizonte necesario hacia el que deben caminar estos proyectos para generar la apropiación de la tecnología en sus formas de uso e imprimir un auténtico valor político a las actividades desarrolladas, y 2) la sostenibilidad, que actúa como base material de dicha acción en el tiempo. A través del estudio de La Marabunta Filmadora, el texto examina críticamente desde esta perspectiva aspectos como la relación con los financiadores externos, el papel de la facilitación, la relación con la comunidad o dinámicas de sostenibilidad en este tipo de propuestas.The text examines key dynamics underpinning participatory video experiences with indigenous collectivities: (1) Autonomy appears here as a very specific and necessary goal, particularly if these projects aim to achieve empowerment and a real political impact within indigenous communities, and (2) Sustainability represents the material ground in order to maintain these actions over time. Taking La Marabunta Filmadora as a case-study, we analyze aspects such as the role played by external funders, facilitation as a process, community dynamics or how sustainability is achieved in these kind of participatory video experiences

Visual Servoing Control of Soft Robots based on Finite Element Model

International audienceIn this paper, we propose a strategy for the control of soft robots with visual tracking and simulation-based predictor. A kinematic model of soft robots is obtained thanks to the Finite Element Method (FEM) computed in real-time. The FEM allows to obtain a prediction of the Jacobian matrix of the robot. This allows a first control of the robot, in the actuator space. Then, a second control strategy based on the feedback of infrared cameras is developed to obtain a correction of the effector position. The robust stability of this closed-loop system is obtained based on Lyapunov stability theory. Otherwise, to deal with the problem of image features (the marker points placed on the end effector of soft robot) loss, a switched control strategy is proposed to combine both the open-loop controller and the closed-loop controller. Finally, experiments on a parallel soft robot driven by four cables are conducted and show the effectiveness of these methods for the real-time control of soft robots

Robust Fabrication of a Soft Mechanosensor based on Pneumatic Measurements

International audienceIn this extended abstract, we complement the work presented in a previous paper where we have shown the modeling of a novel soft pneumatic mechanosensor. With the objective of giving a demo at the RoboTac 2019 workshop, we discuss robust manufacturing techniques that enable us to fabricate such soft mechanosensors out of silicone with embedded cavities in a consistent manner

Finite element method-based kinematics and closed-loop control of soft, continuum manipulators

International audienceThis paper presents a modeling methodology and experimental validation for soft 1 manipulators to obtain forward and inverse kinematic models under quasistatic conditions. It offers a way to obtain the kinematic characteristics of this type of soft robots that is suitable for offline path planning and position control. The modeling methodology presented relies on continuum mechanics which does not provide analytic solutions in the general case. Our approach proposes a real-time numerical integration strategy based on Finite Element Method (FEM) with a numerical optimization based on Lagrangian Multipliers to obtain forward and inverse models. To reduce the dimension of the problem, at each step, a projection of the model to the constraint space (gathering actuators, sensors and end-effector) is performed to obtain the smallest number possible of mathematical equations to be solved. This methodology is applied to obtain the kinematics of two different manipulators with complex structural geometry. An experimental comparison is also performed in one of the robots, between two other geometric approaches and the approach that is showcased in this paper. A closed-loop controller based on a state estimator is proposed. The controller is experimentally validated and its robustness is evaluated using Lypunov stability method

Software toolkit for modeling, simulation and control of soft robots

International audienceThe technological differences between traditional robotics and soft robotics have an impact on all of the modeling tools generally in use, including direct kinematics and inverse models, Jacobians, and dynamics. Due to the lack of precise modeling and control methods for soft robots, the promising concepts of using such design for complex applications (medicine, assistance, domestic robotics...) cannot be practically implemented. This paper presents a first unified software framework dedicated to modeling, simulation and control of soft robots. The framework relies on continuum mechanics for modeling the robotic parts and boundary conditions like actuators or contacts using a unified representation based on Lagrange multipliers. It enables the digital robot to be simulated in its environment using a direct model. The model can also be inverted online using an optimization-based method which allows to control the physical robots in the task space. To demonstrate the effectiveness of the approach, we present various soft robots scenarios including ones where the robot is interacting with its environment. The software has been built on top of SOFA, an open-source framework for deformable online simulation and is available at https://project.inria.fr/softrobot

A Model-based Sensor Fusion Approach for Force and Shape Estimation in Soft Robotics

International audienceIn this paper, we address the challenge of sensor fusion in Soft Robotics for estimating forces and deformations. In the context of intrinsic sensing, we propose the use of a soft capacitive sensor to find a contact's location, and the use of pneumatic sensing to estimate the force intensity and the deformation. Using a FEM-based numerical approach, we integrate both sensing streams and model two Soft Robotics devices we have conceived. These devices are a Soft Pad and a Soft Finger. We show in an evaluation that external forces on the Soft Pad can be estimated and that the shape of the Soft Finger can be reconstructed

Detection of all four dengue serotypes in Aedes aegypti female mosquitoes collected in a rural area in Colombia

The Aedes aegypti vector for dengue virus (DENV) has been reported in urban and periurban areas. The information about DENV circulation in mosquitoes in Colombian rural areas is limited, so we aimed to evaluate the presence of DENV in Ae. aegypti females caught in rural locations of two Colombian municipalities, Anapoima and La Mesa. Mosquitoes from 497 rural households in 44 different rural settlements were collected. Pools of about 20 Ae. aegypti females were processed for DENV serotype detection. DENV in mosquitoes was detected in 74% of the analysed settlements with a pool positivity rate of 62%. The estimated individual mosquito infection rate was 4.12% and the minimum infection rate was 33.3/1,000 mosquitoes. All four serotypes were detected; the most frequent being DENV-2 (50%) and DENV-1 (35%). Two-three serotypes were detected simultaneously in separate pools. This is the first report on the co-occurrence of natural DENV infection of mosquitoes in Colombian rural areas. The findings are important for understanding dengue transmission and planning control strategies. A potential latent virus reservoir in rural areas could spill over to urban areas during population movements. Detecting DENV in wild-caught adult mosquitoes should be included in the development of dengue epidemic forecasting models

The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts

Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species’ threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project – and avert – future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups – including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems – www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015