An energy flow study of a double-deck tunnel under quasi-static and harmonic excitations

© 2016. This version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/This paper presents a comparison between the vibration energy flow radiated by a double-deck tunnel and the one radiated by a simple tunnel when both are excited by constant or by harmonic moving loads. For both cases, the radiated energy is computed using a three-dimensional semi-analytical model of the system. The total energy radiated upwards is presented for a wide range of load speeds, when a constant moving load is considered, and for a wide range of excitation frequencies, when the excitation is a harmonic moving load. Significant differences have been obtained, first, for constant loads moving at very high speeds and, second, for harmonic loads moving at typical speeds for underground trains.Peer ReviewedPostprint (author's final draft

Exploiting the robot kinematic redundancy for emotion conveyance to humans as a lower priority task

Current approaches do not allow robots to execute a task and simultaneously convey emotions to users using their body motions. This paper explores the capabilities of the Jacobian null space of a humanoid robot to convey emotions. A task priority formulation has been implemented in a Pepper robot which allows the specification of a primary task (waving gesture, transportation of an object, etc.) and exploits the kinematic redundancy of the robot to convey emotions to humans as a lower priority task. The emotions, defined by Mehrabian as points in the pleasure–arousal–dominance space, generate intermediate motion features (jerkiness, activity and gaze) that carry the emotional information. A map from this features to the joints of the robot is presented. A user study has been conducted in which emotional motions have been shown to 30 participants. The results show that happiness and sadness are very well conveyed to the user, calm is moderately well conveyed, and fear is not well conveyed. An analysis on the dependencies between the motion features and the emotions perceived by the participants shows that activity correlates positively with arousal, jerkiness is not perceived by the user, and gaze conveys dominance when activity is low. The results indicate a strong influence of the most energetic motions of the emotional task and point out new directions for further research. Overall, the results show that the null space approach can be regarded as a promising mean to convey emotions as a lower priority task.Postprint (author's final draft

The dynamic role of ICT in extracurricular learning: specific training and educational innovation

El impacto de las TIC convierte la docencia superior en una tarea prolongable más allá del espacio del aula. La visibilización de los resultados de la docencia es una labor en constante renovación para lograr hacer perceptibles las producciones audiovisuales, tanto para los alumnos como para el profesorado. Por todo ello, la oferta de un complemento formativo consistente en talleres y cursos específicos que motiven a los estudiantes a la hora de profundizar en algunas materias, es un elemento clave en la formación integral impartida en el área de conocimiento de Comunicación audiovisual, Periodismo o Publicidad.The impact of ICT teaching in higher education becomes an extendable assignment beyond the classroom space. The visibility of the results of teaching is a task that is constantly renewed to achieve perceptible audiovisual productions, both for students and teachers. Therefore, the offer of an educational supplement that consists of workshops and specific courses that encourage students to study some subjects in depth, is considered an essential element in the comprehensive training taught in the area of knowledge of Audiovisual Communication, Journalism or Advertisin

Teleoperating a mobile manipulator and a free-flying camera from a single haptic device

© 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksThe paper presents a novel teleoperation system that allows the simultaneous and continuous command of a ground mobile manipulator and a free flying camera, implemented using an UAV, from which the operator can monitor the task execution in real-time. The proposed decoupled position and orientation workspace mapping allows the teleoperation from a single haptic device with bounded workspace of a complex robot with unbounded workspace. When the operator is reaching the position and orientation boundaries of the haptic workspace, linear and angular velocity components are respectively added to the inputs of the mobile manipulator and the flying camera. A user study on a virtual environment has been conducted to evaluate the performance and the workload on the user before and after proper training. Analysis on the data shows that the system complexity is not an obstacle for an efficient performance. This is a first step towards the implementation of a teleoperation system with a real mobile manipulator and a low-cost quadrotor as the free-flying camera.Accepted versio

Dynamic response of a double-deck circular tunnel embedded in a full-space

© 2016. This version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/A three-dimensional dynamic model for calculating the ground-borne vibrations generated by harmonic loads applied on the interior floor of a double-deck circular tunnel is developed. The response of the system is obtained coupling the interior floor subsystem and the tunnel-soil subsystem in the wavenumber-frequency domain. The interior floor is modeled as a thin plate of infinite length in the train circulation direction and the tunnel-soil system is described using the Pipe in Pipe model. Some numerical instabilities of the resulting expressions are overcome by using analytic approximations. The results show that the dynamic behavior of the interior floor clearly influences the magnitude of the coupling loads acting on the tunnel structure. The soil response to a harmonic load acting on the double-deck tunnel is compared to the one obtained for the case of a simple tunnel finding significant differences between them for the whole range of frequencies studied. The proposed model extends the prediction of train-induced vibrations using computationally efficient models to this type of tunnel structure.Peer ReviewedPostprint (author's final draft

Modelling and simulation of a magnetically coupled multiport dc-dc converter

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksThis paper present two different approaches for modelling a magnetically coupled multiport dc-dc converter. First, from the magnetic coupling equations, the instantaneous dynamic model is obtained. Secondly, a behavioural dynamic model, based on averaging the power flowing among the ports, is derived. Some numerical simulations compare the temporal evolutions with the two obtained modelsPeer ReviewedPostprint (author's final draft

Searching a valid hand configuration to perform a given grasp

Peer ReviewedPostprint (published version

The audiovisual tapeless and the collapse of linearity in the story

En este momento de profundas transformaciones en el sector audiovisual, el recorrido realizado en el presente trabajo muestra cómo el siglo XX fue el de la aparición y consolidación de los medios de comunicación de masas (1.0) y el de la superación de sus limitaciones narrativas y de su unidireccionalidad. A finales del siglo XX y en los inicios del siglo XXI, la irrupción de la Web ha modificado el escenario (ahora 2.0) y la interactividad del usuario es ya una realidad sin renunciar por supuesto a las posibilidades que ofrece el consumo lineal del relato.The audiovisual sector is inside a deep transformation. In this context, this paper analyses the evolution in the twentieth century, with the emergence and consolidation of the mass media (1.0). Now the narrative limitation and the linear tale is something past. In the late twentieth and early twenty-first century, the emergence of the Web has changed the scenario (now 2.0) and user interactivity is a fact. The challenge is discover how to introduce the benefits without loosing the advantges of the traditional narration

GEOPLEX: Back-to-back converter for an electrical machine application

The architecture of a back-to-back converter, needed to feed the rotor windings of a 3-phase doubly-fed induction machine and such that power can flow both ways, is described, from both the modelling and experimental viewpoints. In particular, a PCHS model using selected GSSA variables is described in detail. Some new and improved results concerning the detailed PCHS structure of a GSSA expansion of a PCHS are also presented

A 2.5D automatic FEM-SBM method for the evaluation of free-field vibrations induced by underground railway infrastructures

This paper presents an efficient method to predict underground railway-induced vibrations. The method uses the finite element method (FEM) to model the railway tunnel structure and the singular boundary method (SBM) to model the wave propagation in the surrounding soil. The FEM mesh and the distribution of SBM collocation points at the tunnel/soil interface are generated using an automatic meshing strategy. The presented method is one of the main components of VIBWAY, a user-friendly prediction tool to address railway-induced vibration problems. This paper presents three calculation examples in which the soil response due to forces applied on the tunnel structure are computed in terms of transfer functions. The results obtained for each one of the calculation examples are compared with those computed using a model based on a 2.5D FEM-BEM approach. The presented comparisons show that the proposed approach is a suitable strategy for predicting underground railway-induced vibrations, both in terms of accuracy and computational efficiency. Moreover, the use of an automatic meshing strategy and the SBM formulation not only eases the implementation of the approach but it also makes it easier to use, which is one of the key features of the VIBWAY tool.Peer ReviewedPostprint (published version