Planning robot formations with fast marching square including uncertainty conditions

This paper presents a novel algorithm to solve the robot formation path planning problem working under uncertainty conditions such as errors the in robot's positions, errors when sensing obstacles or walls, etc. The proposed approach provides a solution based on a leader-followers architecture (real or virtual leaders) with a prescribed formation geometry that adapts dynamically to the environment. The algorithm described herein is able to provide safe, collision-free paths, avoiding obstacles and deforming the geometry of the formation when required by environmental conditions (e.g. narrow passages). To obtain a better approach to the problem of robot formation path planning the algorithm proposed includes uncertainties in obstacles' and robots' positions. The algorithm applies the Fast Marching Square (FM2) method to the path planning of mobile robot formations, which has been proved to work quickly and efficiently. The FM2 method is a path planning method with no local minima that provides smooth and safe trajectories to the robots creating a time function based on the properties of the propagation of the electromagnetic waves and depending on the environment conditions. This method allows to easily include the uncertainty reducing the computational cost significantly. The results presented here show that the proposed algorithm allows the formation to react to both static and dynamic obstacles with an easily changeable behavior.This work is included in the project number DPI2010-17772 funded by the Spanish Ministry of Science and Innovation and has been supported by the CAM Project S2009/DPI-1559/ROBOCITY2030 II, developed by the research team RoboticsLab at the University Carlos III of Madrid.Publicad

Flexible solvent-free polymer electrolytes for solid-state Na batteries

Post-lithium batteries, based on alkaline and alkaline earth elements, are cheaper technologies with the potential to produce disruptive changes in the transition towards cleaner and sustainable energy sources less dependent on fossil fuels. This contribution deals with the development and characterization of sodium-conducting solvent-free polymer electrolytes towards the attainment of Sodium Polymer Batteries. Obtained via the polycondensation of α, ω-dihydroxy-oligo(oxyethylene) with an unsaturated dihalide, whose further curing leads to amorphous networked electrolyte films. Using NaClO4 and NaCF3SO3 at different O/Na ratios, the best polymer electrolyte reaches a cationic conductivity (σ+) exceeding 1 mS cm−1 at 90 °C whereas maintaining mechanical integrity up to at least 120 °C.The authors would like to thank the Agencia Española de Investigación/Fondo Europeo de Desarrollo Regional (FEDER/UE) for funding the project PID2019-106662RBC43. This work has been supported by the Madrid Government (Comunidad de Madrid-Spain) through three projects: 1) the Multiannual Agreement with UC3M ("Fostering Young Doctors Research", CIRENAICA-CM-UC3M), and in the context of the VPRICIT (Research and Technological Innovation Regional Programme); 2) the Multiannual agreement with UC3M ("Excelencia para el Profesorado Universitario" - EPUC3M04) - Fifth regional research plan 2016-2020; 3) DROMADER-CM (Y2020/NMT6584). B.P. and A.V. acknowledge support from the CONEX-Plus programme funded by Universidad Carlos III de Madrid and the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 801538

New amphiphilic semi-interpenetrating networks based on polysulfone for anion-exchange membrane fuel cells with improved alkaline and mechanical stabilities

As considerable advance has recently been made in enhancing the conductivity of anion-exchange membranes, durability has become the critical requirement in the development of fuel cells. Such properties often develop at the expense of the other. In this work, new amphiphilic semi-interpenetrating networks composed of free polysulfone and crosslinked polysulfone are synthesized for the first time. The same nature of both polymers makes them highly compatible. The free polymer provides the hydrophobic component, whereas the crosslinked polysulfone, functionalized with trimethylammonium, 1-methylimidazolium, or 1,2-dimethylimidazolium groups, is responsible for the ionic conductivity. The compatibility between both components in the blend, improves the mechanical properties, while unaffecting the transport properties. Thus, the obtained membranes exceed the mechanical behaviour of commercial materials, even in conditions of extreme humidity and temperature. The tensile strength of these synthesized membranes can reach to relatively high values, and when compared to the commercial PSU, the difference in tensile strength can be noted to be as low as 10%. Moreover, the tensile strength and the ductility values of the crosslinked PSU are higher than those obtained with non-crosslinked PSU. Furthermore, the membranes presented in this work show a great alkaline stability (e.g. semi-interpenetrating network containing 1,2-dimethylimidazolium maintains 87% of the ionic conductivity after 14 days of treatment). Thus, these membranes provide an improvement in the durability limiting factors, in comparison to functionalized polysulfones, fulfilling the requirements to be used as electrolytes in anion-exchange membrane fuel cells.We thank Agencia Estatal de Investigación (AEI)/Fondo Europeo de Desarrollo Regional (FEDER/UE) for funding the project MINECO (MAT2016-78632-C4-3-R, and PID-2019-106662RB-C43) which supported this work. We also wish to thank the project from the Regional Government (Comunidad de Madrid through PEM4ENERGY-CM-UC3M)

Development of sodium hybrid quasi-solid electrolytes based on porous NASICON and ionic liquids

Lithium-ion batteries are currently the alternative of choice to overcome the increasing demand of energy. However, besides the scarcity of lithium and limited geolocation, it is believed that such batteries have already reached their maximum maturity. Sodium batteries emerge as an alternative to produce the new, so called, post-lithium batteries. In this study, we explore (i) the effect of sodium content and sintering temperature in solid electrolytes based in NASICON-type compounds and (ii) the use of two methodologies to obtain porous NASICON samples: application of natural substances and organic materials as pore-formers and freeze casting. The main purpose is the attainment of hybrid quasi-solid state electrolytes, with enhanced room temperature conductivity, based on porous ceramic electrolyte layers infiltrated with ionic liquids. Using this approach, porous samples with different microstructure and porous morphology and distribution were achieved, providing an enhancement in conductivity (ranging from 0.45 to 0.96 mS cm−1 at 30 °C) of one order of magnitude for infiltrated samples respect to pore-free samples. According to these results the porous NASICON might be considered as a functional macroporous inorganic separator that can act as a Na+ reservoir.The authors would like to thank the Agencia Española de Investigación /Fondo Europeo de Desarrollo Regional (FEDER/UE) for funding the projects PID2019-106662RBC43. This work has also been supported by Comunidad de Madrid (Spain) - multiannual agreement with UC3M ("Excelencia para el Profesorado Universitario" - EPUC3M04) - Fifth regional research plan 2016-2020

Synthesis and characterization of novel anion exchange membranes based on semi-interpenetrating networks of functionalized polysulfone: Effect of ionic crosslinking

This article belongs to the Special Issue Polymeric Membranes for Advanced Applications.In this work, anion exchange membranes based on polymer semi-interpenetrating networks were synthesized and characterized for the first time. The networks are composed of sulfonated polysulfone and 1-methylimidazolium-functionalized polysulfone crosslinked covalently with N,N,N′,N′-tetramethylethylenediamine (degree of crosslinking of 5%). In these membranes, sulfonic groups interact electrostatically with cationic groups to form an ionic crosslinking structure with improved alkaline stability. The effect of the ionic crosslinking on the thermal, chemical, mechanical, and electrochemical behavior of membranes was studied. These crosslinked membranes containing sulfonated polysulfone showed higher thermal stability, with a delay of around 20 °C in the onset decomposition temperature value of the functional groups than the crosslinked membranes containing free polysulfone. The tensile strength values were maintained above 44 MPa in all membranes with a degree of chloromethylation (DC) below 100%. The maximum ionic conductivity value is reached with the membrane with the highest degree of chloromethylation. The chemical stability in alkaline medium of the conducting membranes also improved. Thus, the ionic conductivity variation of the membranes after 96 h in a 1 M potassium hydroxide (KOH) solution is less pronounced when polysulfone is replaced by sulfonated polysulfone. So, the ionic crosslinking which joins both components of the blends together, improves the material’s properties making progress in the development of new solid electrolyte for polymeric fuel cells.This work was funded by Agencia Estatal de Investigación (AEI)/Fondo Europeo de Desarrollo Regional (FEDER/UE), PID-2019-106662RB-C43, by the Spanish Government, MAT2016-78632-C4-3-R, and by the Regional Government PEM4ENERGY-CM-UC3M funded by the call "Programa de apoyo a la realización de proyectos interdisciplinares de I+D para jóvenes investigadores de la Universidad Carlos III de Madrid 2019-2020" under the frame of the "Convenio Plurianual Comunidad de Madrid-Universidad Carlos III de Madrid"

Interplay between Conductivity, Matrix Relaxations and Composition of Ca-Polyoxyethylene Polymer Electrolytes

This article also appears in: In Memoriam: Prof. Jean-Michel Savéant.In this report, the conductivity mechanism of Ca2+-ion in polyoxyethylene (POE) solid polymer electrolytes (SPEs) for calcium secondary batteries is investigated by broadband electrical spectroscopy studies. SPEs are obtained by dissolving into the POE hosting matrix three different calcium salts: CaTf2, Ca(TFSI)2 and CaI2. The investigation of the electric response of the synthetized SPEs reveals the presence in materials of two polarization phenomena and two dielectric relaxation events. It is demonstrated that the nature of the anion (i. e., steric hindrance, charge density and ability to act as coordination ligand) and the density of “dynamic crosslinks” of SPEs is fundamental in the establishment of ion-ion/ion-polymer interactions. The long-range charge migration processes occurring along the two revealed percolation pathways of the electrolytes are generally coupled with the polymer host dynamics and depend on the temperature and the anion nature. This study offers the needed tools for understanding Ca2+ conduction in POE-based electrolytes.This work has been supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 829145(FETOPEN-VIDICAT).V. Di Notothanks the University CarlosIII of Madrid for the “Catedras de Excelencia UC3M-Santander” (Chairof Excellence UC3M-Santander)

Reduction of Grain Boundary Resistance of La0.5Li0.5TiO3 by the Addition of Organic Polymers

The organic solvents that are widely used as electrolytes in lithium ion batteries present safety challenges due to their volatile and flammable nature. The replacement of liquid organic electrolytes by non-volatile and intrinsically safe ceramic solid electrolytes is an effective approach to address the safety issue. However, the high total resistance (bulk and grain boundary) of such compounds, especially at low temperatures, makes those solid electrolyte systems unpractical for many applications where high power and low temperature performance are required. The addition of small quantities of a polymer is an efficient and low cost approach to reduce the grain boundary resistance of inorganic solid electrolytes. Therefore, in this work, we study the ionic conductivity of different composites based on non-sintered lithium lanthanum titanium oxide (La0.5Li0.5TiO3) as inorganic ceramic material and organic polymers with different characteristics, added in low percentage (<15 wt.%). The proposed cheap composite solid electrolytes double the ionic conductivity of the less cost-effective sintered La0.5Li0.5TiO3.We thank the Spanish Ministry for Science and Technology (MAT2007-64486-C07-05) and CDTI (ALMAGRID of the "CERVERA Centros Tecnológicos" program, CER-20191006) for financial their support. JS, AV, SG, and FG also want to acknowledge Agencia Española de Investigación /Fondo Europeo de Desarrollo Regional (FEDER/UE) for funding the projects PID2019-106662RB-C41, C42, C43, and C44

Proyecto para la incorporación de las nuevas tecnologías en las comunicaciones del programa de prevención del cáncer de mama en Navarra

Ingeniería Técnica de Telecomunicación, especialidad Sonido e ImagenTelekomunikazio Ingeniaritza Teknikoa. Soinua eta Irudia Berezitasun

Métodos de visión artificial para la extracción de la pose de la mano humana y su representación virtual

Mención Internacional en el título de doctorEs impensable diseñar un robot, desde los más simples como los empleados en labores domésticas, pasando por los de asistencia a personas o los más complejos dedicados a la investigación espacial, sin tener en cuenta la interacción que tendrán con el medio. Llegados a este punto, la visión tiene un papel fundamental, ya que permite obtener información con la que podemos interpretar de forma rápida la situación a nuestro alrededor, como por ejemplo posibles peligros, objetos que podemos utilizar, distancias aproximadas, etc. La visión es, por tanto, una de las primeras fuentes de información que tenemos para hacernos una idea el entorno que nos rodea, pero no solo se trata de algo superficial, sino que también nos resulta útil cuando queremos realizar tareas complejas y delicadas, como por ejemplo, la manipulación diestra de herramientas. Es aquí donde entra en juego esta tesis, se busca la manera de estudiar la información de la mano, que proporciona un sensor 3D, para poder extrapolar estos datos y controlar así una mano robótica. Lo que a priori puede parecer un problema fácilmente resoluble, por la aparente sencillez con que nosotros evaluamos nuestro entorno, se trata de algo realmente complejo de codificar para que sea interpretado por un ordenador. Mientras que nosotros somos capaces de clasificar y diferenciar los elementos que componen el entorno sin dificultad, el robot se encuentra con un conjunto de puntos sin una relación aparente entre sí. Nuestra función es la de enseñar al sistema como interpretar dicha información y ayudarlo a discriminar los distintos objetos y no solo eso, sino dentro de un mismo objeto identificar las partes que lo componen, en este caso, la muñeca, dedos, falanges y yemas que dan forma a la mano.This work is included in the project number BES-2011-044230 funded by the Spanish Ministry of Science and Innovation. Robotics Lab – Universidad Carlos III de MadridPrograma Oficial de Doctorado en Ingeniería Eléctrica, Electrónica y AutomáticaPresidente: Fabio Bonsignorio.- Secretario: María Dolores Blanco Rojas.- Vocal: Antonio Giménez Fernánde

Trade-off analysis of C12A7: e-deposition techniques applied to Low Work Function Tethers

Due to its extraordinary properties, the C12A7:e− electride has been suggested in the past as one of the most promising materials for coating Low Work-function Tethers (LWTs). Such subclass of electrodynamic tether, made of a conductive substrate coated with materials that enhance the electron emission through the thermionic and photoelectric effects, would constitute a fully passive and consumable-free device for deorbiting space debris from Low Earth Orbit. This work presents experimental results on the manufacturing and testing of small tape-like LWT samples, which is the relevant geometry for electrodynamic tether applications. After preparing C12A7:e− targets under specific and controlled conditions, thin titanium foils have been coated with the C12A7:e− electride by using two different physical vapor deposition techniques: magnetron sputtering (MS) and pulsed laser deposition (PLD). In the case of MS, important difficulties and defects were found, including target damage, poor growth rate, and oxidation and changes in the composition of the coating. However, the performance on the PLD coating was radically different. First, Rutherford backscattering spectrometry confirmed that the composition of the thin film with the PLD coincides with that of the target. Second, X-ray photoelectron spectroscopy and thermionic emission experiments showed that the work function of the LWT sample is 2.6 ± 0.1 eV. Therefore, the trade-off analysis indicates that PLD can be used to manufacture LWT samples with work function close to the one of the bulk C12A7:e− (2.4 eV). Nevertheless, its application as passive cathode in electrodynamic tethers still requires further research activities.This work was supported by Agencia Estatal de Investigación (Ministerio de Ciencia, Innovación y Universidades of Spain) under the project ESP2017-82092-ERC (AEI). Work by JFP and AP has been supported by the Centro para el Desarrollo Tecnológico e Industrial (CDTI) under the project IDI-20171255. FJP and PT acknowledge the support by ATD under project contract ICMM-CSIC #010101170104. SN work is supported by Comunidad de Madrid (Spain) under the Grant 2018/T2IND/11352. GSA work is supported by the Ministerio de Ciencia, Innovación y Universidades of Spain under the Grant RYC-2014-15357