Visual perception for the 3D recognition of geometric pieces in robotic manipulation

During grasping and intelligent robotic manipulation tasks, the camera position relative to the scene changes dramatically because the robot is moving to adapt its path and correctly grasp objects. This is because the camera is mounted at the robot effector. For this reason, in this type of environment, a visual recognition system must be implemented to recognize and “automatically and autonomously” obtain the positions of objects in the scene. Furthermore, in industrial environments, all objects that are manipulated by robots are made of the same material and cannot be differentiated by features such as texture or color. In this work, first, a study and analysis of 3D recognition descriptors has been completed for application in these environments. Second, a visual recognition system designed from specific distributed client-server architecture has been proposed to be applied in the recognition process of industrial objects without these appearance features. Our system has been implemented to overcome problems of recognition when the objects can only be recognized by geometric shape and the simplicity of shapes could create ambiguity. Finally, some real tests are performed and illustrated to verify the satisfactory performance of the proposed system.

Blazed Gratings Recorded in Absorbent Photopolymers

Phase diffractive optical elements, which have many interesting applications, are usually fabricated using a photoresist. In this paper, they were made using a hybrid optic-digital system and a photopolymer as recording medium. We analyzed the characteristics of the input and recording light and then simulated the generation of blazed gratings with different spatial periods in different types of photopolymers using a diffusion model. Finally, we analyzed the output and diffraction efficiencies of the 0 and 1st order so as to compare the simulated values with those measured experimentally. We evaluated the effects of index matching in a standard PVA/AA photopolymer, and in a variation of Biophotopol, a more biocompatible photopolymer. Diffraction efficiencies near 70%, for a wavelength of 633 nm, were achieved for periods longer than 300 µm in this kind of materials.

GU Monocerotis: A high-mass eclipsing overcontact binary in the young open cluster Dolidze 25

Context. The eclipsing binary GU Mon is located in the star-forming cluster Dolidze 25, which has the lowest metallicity measured in a Milky Way young cluster. Aims. GU Mon has been identified as a short-period eclipsing binary with two early B-type components. We set out to derive its orbital and stellar parameters. Methods. We present a comprehensive analysis, including B and V light curves and 11 high-resolution spectra, to verify the orbital period and determine parameters. We used the stellar atmosphere code FASTWIND to obtain stellar parameters and create templates for cross-correlation. We obtained a model to fit the light and radial-velocity curves using the Wilson-Devinney code iteratively and simultaneously. Results. The two components of GU Mon are identical stars of spectral type B1 V with the same mass and temperature. The light curves are typical of an EW-type binary. The spectroscopic and photometric analyses agree on a period of 0.896640 ± 0.000007 d. We determine a mass of 9.0 ± 0.6 M⊙ for each component and for temperatures of 28 000 ± 2000 K. Both values are consistent with the spectral type. The two stars are overfilling their respective Roche lobes, sharing a common envelope and, therefore the orbit is synchronised and circularised. Conclusions. The GU Mon system has a fill-out factor above 0.8, containing two dwarf B-type stars on the main sequence. The two stars are in a very advanced stage of interaction, with their extreme physical similarity likely due to the common envelope. The expected evolution of such a system very probably leads to a merger while still on the main sequence.

3D Visual Data-Driven Spatiotemporal Deformations for Non-Rigid Object Grasping Using Robot Hands

Sensing techniques are important for solving problems of uncertainty inherent to intelligent grasping tasks. The main goal here is to present a visual sensing system based on range imaging technology for robot manipulation of non-rigid objects. Our proposal provides a suitable visual perception system of complex grasping tasks to support a robot controller when other sensor systems, such as tactile and force, are not able to obtain useful data relevant to the grasping manipulation task. In particular, a new visual approach based on RGBD data was implemented to help a robot controller carry out intelligent manipulation tasks with flexible objects. The proposed method supervises the interaction between the grasped object and the robot hand in order to avoid poor contact between the fingertips and an object when there is neither force nor pressure data. This new approach is also used to measure changes to the shape of an object’s surfaces and so allows us to find deformations caused by inappropriate pressure being applied by the hand’s fingers. Test was carried out for grasping tasks involving several flexible household objects with a multi-fingered robot hand working in real time. Our approach generates pulses from the deformation detection method and sends an event message to the robot controller when surface deformation is detected. In comparison with other methods, the obtained results reveal that our visual pipeline does not use deformations models of objects and materials, as well as the approach works well both planar and 3D household objects in real time. In addition, our method does not depend on the pose of the robot hand because the location of the reference system is computed from a recognition process of a pattern located place at the robot forearm. The presented experiments demonstrate that the proposed method accomplishes a good monitoring of grasping task with several objects and different grasping configurations in indoor environments.

Measuring the stellar wind parameters in IGR J17544-2619 and Vela X-1 constrains the accretion physics in supergiant fast X-ray transient and classical supergiant X-ray binaries

Context. Classical supergiant X-ray binaries (SGXBs) and supergiant fast X-ray transients (SFXTs) are two types of high-mass X-ray binaries (HMXBs) that present similar donors but, at the same time, show very different behavior in the X-rays. The reason for this dichotomy of wind-fed HMXBs is still a matter of debate. Among the several explanations that have been proposed, some of them invoke specific stellar wind properties of the donor stars. Only dedicated empiric analysis of the donors’ stellar wind can provide the required information to accomplish an adequate test of these theories. However, such analyses are scarce. Aims. To close this gap, we perform a comparative analysis of the optical companion in two important systems: IGR J17544-2619 (SFXT) and Vela X-1 (SGXB). We analyze the spectra of each star in detail and derive their stellar and wind properties. As a next step, we compare the wind parameters, giving us an excellent chance of recognizing key differences between donor winds in SFXTs and SGXBs. Methods. We use archival infrared, optical and ultraviolet observations, and analyze them with the non-local thermodynamic equilibrium (NLTE) Potsdam Wolf-Rayet model atmosphere code. We derive the physical properties of the stars and their stellar winds, accounting for the influence of X-rays on the stellar winds. Results. We find that the stellar parameters derived from the analysis generally agree well with the spectral types of the two donors: O9I (IGR J17544-2619) and B0.5Iae (Vela X-1). The distance to the sources have been revised and also agree well with the estimations already available in the literature. In IGR J17544-2619 we are able to narrow the uncertainty to d = 3.0 ± 0.2 kpc. From the stellar radius of the donor and its X-ray behavior, the eccentricity of IGR J17544-2619 is constrained to e< 0.25. The derived chemical abundances point to certain mixing during the lifetime of the donors. An important difference between the stellar winds of the two stars is their terminal velocities (ν∞ = 1500 km s-1 in IGR J17544-2619 and ν∞ = 700 km s-1 in Vela X-1), which have important consequences on the X-ray luminosity of these sources. Conclusions. The donors of IGR J17544-2619 and Vela X-1 have similar spectral types as well as similar parameters that physically characterize them and their spectra. In addition, the orbital parameters of the systems are similar too, with a nearly circular orbit and short orbital period. However, they show moderate differences in their stellar wind velocity and the spin period of their neutron star which has a strong impact on the X-ray luminosity of the sources. This specific combination of wind speed and pulsar spin favors an accretion regime with a persistently high luminosity in Vela X-1, while it favors an inhibiting accretion mechanism in IGR J17544-2619. Our study demonstrates that the relative wind velocity is critical in class determination for the HMXBs hosting a supergiant donor, given that it may shift the accretion mechanism from direct accretion to propeller regimes when combined with other parameters.

Multiwavelength study of the fast rotating supergiant high-mass X-ray binary IGR J16465−4507

Context. Since its launch, the X-ray and γ-ray observatory INTEGRAL satellite has revealed a new class of high-mass X-ray binaries (HMXB) displaying fast flares and hosting supergiant companion stars. Optical and infrared (OIR) observations in a multi-wavelength context are essential to understand the nature and evolution of these newly discovered celestial objects. Aims. The goal of this multiwavelength study (from ultraviolet to infrared) is to characterise the properties of IGR J16465−4507, to confirm its HMXB nature and that it hosts a supergiant star. Methods. We analysed all OIR, photometric and spectroscopic observations taken on this source, carried out at ESO facilities. Results. Using spectroscopic data, we constrained the spectral type of the companion star between B0.5 and B1 Ib, settling the debate on the true nature of this source. We measured a high rotation velocity of v = 320 ± 8km s-1 from fitting absorption and emission lines in a stellar spectral model. We then built a spectral energy distribution from photometric observations to evaluate the origin of the different components radiating at each energy range. Conclusions. We finally show that, having accurately determined the spectral type of the early-B supergiant in IGR J16465−4507, we firmly support its classification as an intermediate supergiant fast X-ray transient (SFXT).

Iluminando a las investigadoras en el Año Internacional de la Luz

El año 2015 fue declarado por las Naciones Unidas como el Año Internacional de la Luz y de las Tecnologías basadas en la luz. Varias personas pertenecientes al Grupo Especializado de Mujeres en Física de la Real Sociedad Española de Física (RSEF) y a la Sociedad Española de Óptica (SEDOPTICA) nos organizamos para llevar a cabo distintas actividades con objeto de visibilizar a algunas investigadoras que han realizado su labor científica en estos campos y cuyas contribuciones son poco o nada conocidas. Animadas por dos de los objetivos de la declaración del año 2015 como el Año Internacional de la Luz y de las Tecnologías basadas en la Luz, a saber: “promocionar el empoderamiento de la mujer en la Ciencia” y “fomentar vocaciones científicas en el ámbito de la luz y de sus aplicaciones”, surgió nuestra motivación. Indudablemente dando visibilidad a la labor de estas científicas y valorando sus aportaciones en el avance de las tecnologías ópticas y fotónicas de nuestra sociedad crearemos referentes para las futuras generaciones y, sobre todo, para las jóvenes estudiantes, contribuyendo a la consecución de la igualdad efectiva entre mujeres y hombres.

Red de seguimiento del Grado en Criminología on line

La red tenía por objeto llevar a cabo un especial seguimiento del grupo on line del Grado en Criminología que se imparte en la titulación y para el que son necesarios esfuerzos de coordinación adicionales y métodos docentes específicos a la docencia no presencial. Así, la red ha constituido un espacio de reflexión sobre docencia no presencial, que ha dado como resultado la adopción e implementación de acciones de mejora.

Protocol to design techniques for implementing software development best practices

Software engineering best practices allow significantly improving the software development. However, the implementation of best practices requires skilled professionals, financial investment and technical support to facilitate implementation and achieve the respective improvement. In this paper we proposes a protocol to design techniques to implement best practices of software engineering. The protocol includes the identification and selection of process to improve, the study of standards and models, identification of best practices associated with the process and the possible implementation techniques. In addition, technical design activities are defined in order to create or adapt the techniques of implementing best practices for software development.

Teleoperación de un robot móvil mediante dispositivos Android

Resumen: En el siguiente trabajo se aborda un problema para solventar la comunicación con los robots del departamento MAPIR de la Universidad de Málaga, anteriormente sólo podían ser teleoperados mediante comandos escritos en Skype, así que se procede a diseñar un cliente móvil para Android que nos permite conectarse en tiempo real a un robot, obtener la imagen de lo que su cámara capta y además permitir su teleoperación. Por su parte, el robot corre un servidor que administra esos datos al cliente para trabajar conjuntamente. Dicho trabajo se desarrolla haciendo uso de nuevas tecnologias y protocolos como es WebRTC (de Google) para el intercambio de imágenes y del lado del servidor, se ha usado NodeJS.

Modelado orientado a objetos del sistema de control de la presión arterial en pacientes sometidos al tratamiento de hemodiálisis

Se ha realizado el modelado orientado a objetos del sistema de control cardiovascular en situaciones de diálisis aplicando una analogía eléctrica en el que se emplean componentes conectados mediante interconexiones. En este modelado se representan las ecuaciones diferenciales del sistema cardiovascular y del sistema de control barorreceptor así como las ecuaciones dinámicas del intercambio de fluidos y solutos del sistema hemodializador. A partir de este modelo se ha realizado experiencias de simulación en condiciones normales y situaciones de hemorragias, transfusiones de sangre y de ultrafiltración e infusión de fluido durante tratamiento de hemodiálisis. Los resultados obtenidos muestran en primer lugar la efectividad del sistema barorreceptor para compensar la hipotensión arterial inducida por los episodios de hemorragia y transfusión de sangre. En segundo lugar se muestra la respuesta del sistema de control ante diferentes tasas de ultrafiltración durante la hemodiálisis y se sugieren valores óptimos para la adecuada operación.

Navegación de un robot móvil sobre terreno irregular con contacto de su brazo con el suelo

En esta tesis se aborda el problema de la navegabilidad de robots móviles sobre terrenos irregulares, los cuales poseen diferentes inclinaciones y variedad de obstáculos. Este tema constituye actualmente una línea de investigación activa dirigida al desarrollo de nuevos robots y, adicionalmente, enfocada al desarrollo de estrategias de navegación eficientes y con el mínimo riesgo de inutilización. En primer lugar se desarrolló el robot móvil Lázaro para navegar en este tipo de terrenos, el cual posee un brazo articulado con una rueda como efector final. Esta rueda le permite al brazo mantener un punto de contacto adicional con el suelo que puede ayudar al robot a compensar situaciones de inestabilidad y sobrepasar algunos obstáculos que pudieran presentarse en estos entornos. Posteriormente, se desarrollaron tres medidas cuantitativas que permiten evaluar la navegabilidad de cualquier robot móvil cuando transita sobre terreno irregular. Estas tres medidas son: un índice de estabilidad, el cual evalúa la propensión al vuelco; un índice de direccionamiento, el cual evalúa la disponibilidad del robot para direccionarse y seguir una trayectoria dada y, por último, un índice de deslizamiento, el cual evalúa la propensión del robot a deslizarse hacia abajo cuando se desplaza sobre superficies inclinadas. Finalmente, se definieron un conjunto de maniobras que puede ejecutar Lázaro y que están dirigidas a garantizar la navegación cuando el robot se desplaza sobre superficies inclinadas o cuando debe sobrepasar obstáculos tales como escalones, rampas o zanjas. Todas las estrategias diseñadas se fundamentan en el uso del brazo como herramienta adicional que posee el robot para mejorar su navegabilidad.