Haptic teleoperation of the youbot with friction compensation for the base

Haptic devices are bringing new possibilities for teleoperation by increasing the level of awareness that the operator can have over the slave. In other words, they create a stronger link between them. Because it is not enough to have a view of the task at hand, it is better to feel what is really happening at the other side. The main goal of the project is to provide the KUKA youBot with an Omega 6 haptic interface. The operator can feel the movement limitations that the arm’s tooltip may be experiencing, resulting in a better driving practice. But with these new capabilities other concerns arise, like the choice of an appropriate control algorithm, the correct coupling of workspaces or the design of a suitable data handling scheme. However, the current setup has not yet been submitted to a proper system validation and so there is still much work to do in order to increase its overall performance. Since friction can have a major role in the control scheme of the system, the latter should be provided with friction compensation. To achieve this, a study of the youBot wheels motor block friction has been carried out. These results are then also incorporated in the robot simulation. Moreover, when identifying this kind of behaviours some important decisions have to be made in order to get the best results from the time invested. Among those are the selection of a friction model, the system identification experiments and the validation of results. In conclusion, it has been proven that the implementation of a haptic interface for the youBot is not only feasible but that it delivers a greater overall teleoperation experience. Also, although the results of this project are an initial version of the system, the friction compensation for the base motor blocks is already working with acceptable performance. ________________________________________________________________________________________________________________Los dispositivos hápticos están trayendo nuevas posibilidades a la teleoperación, aumentando el nivel de consciencia que el operador puede tener sobre la máquina que dirige. En otras palabras, crean un vínculo más fuerte entre ambos. Y es que a veces no es suficiente visualizar la tarea que se esta realizando, es mejor notar lo que realmente está pasando en el otro lado. El objetivo principal del proyecto es proporcionar al robot youBot de KUKA una interfaz con el dispositivo háptico Omega6. El operador puede notar las limitaciones en los movimientos que la herramienta del brazo robot pueda estar experimentando, resultando así en una mejor experiencia de conducción. Pero con estas nuevas capacidades aparecen otras preocupaciones, como elegir un algoritmo de control apropiado, la correcta unión de los espacios de trabajo o el diseño de un esquema de manejo de datos adecuado. Sin embargo, la instalación actual aún no ha sido sometida a una evaluación de sistema apropiada y por lo tanto todavía hay mucho trabajo por hacer para incrementar el rendimiento general. Ya que la fricción puede tener un rol importante en el esquema de control del sistema, este debería ser provisto con compensación de fricción. Para lograr esto se ha llevado a cabo un estudio de los bloques motor de las ruedas del youBot. Estos resultados se han incorporado también a la simulación del robot. Por otra parte, cuando se identifican esta clase de comportamientos se han de tomar decisiones importantes para obtener los mejores resultados del tiempo empleado. Entre estas están la selección de un modelo de fricción adecuado, los experimentos para identificar el sistema y la validación de los resultados. En conclusión, se ha probado que la implementación del youBot con una interfaz háptica no es solo posible sino que mejora la experiencia general de teleoperación. Además, aunque los resultados del proyecto son una versión inicial del sistema, la compensación de la fricción para los bloques motor de la base ya está funcionando con un rendimiento aceptable.Ingeniería Industria

A novel TRNSYS type for short-term borehole heat exchanger simulation: B2G model

[EN] Models of ground source heat pump (GSHP) systems are used as an aid for the correct design and optimization of the system. For this purpose, it is necessary to develop models which correctly reproduce the dynamic thermal behavior of each component in a short-term basis. Since the borehole heat exchanger (BHE) is one of the main components, special attention should be paid to ensuring a good accuracy on the prediction of the short-term response of the boreholes. The BHE models found in literature which are suitable for short-term simulations usually present high computational costs. In this work, a novel TRNSYS type implementing a borehole-to-ground (B2G) model, developed for modeling the short-term dynamic performance of a BHE with low computational cost, is presented. The model has been validated against experimental data from a GSHP system located at Universitat Politecnica de Valencia, Spain. Validation results show the ability of the model to reproduce the short-term behavior of the borehole, both for a step-test and under normal operating conditions. (C) 2015 Elsevier Ltd. All rights reserved.The present work has been supported by the FP7 European project Advanced ground source heat pump systems for heating and cooling in Mediterranean climate (GROUND-MED).De Rosa, M.; Ruiz Calvo, F.; Corberán Salvador, JM.; Montagud Montalvá, CI.; Tagliafico, L. (2015). A novel TRNSYS type for short-term borehole heat exchanger simulation: B2G model. Energy Conversion and Management. 100:347-357. https://doi.org/10.1016/j.enconman.2015.05.021S34735710

Validación del modelo B2G para un intercambiador enterrado en funcionamiento ON/OFF

El diseño y optimización de sistemas de climatización requiere de la capacidad de predecir y reproducir el comportamiento dinámico de cada componente del sistema. Para sistemas de climatización por bomba de calor acoplada al terreno, uno de los elementos principales a estudiar es el intercambiador enterrado. A lo largo de los últimos años se han desarrollado varios tipos de modelos de intercambiador enterrado, con distintas características en función del planteamiento utilizado. Sin embargo, muchos de los modelos existentes se basan en aproximaciones de régimen permanente, por lo que no permiten simular el comportamiento dinámico del intercambiador, mientras que los que sí lo permiten resultan ser modelos altamente complejos, con un elevado coste computacional, lo que dificulta y restringe su uso. En la Universitat Politècnica de València (UPVLC) se ha estado desarrollando un modelo completo de una instalación de climatización por bomba de calor acoplada al terreno. En el marco del desarrollo de este modelo, ha sido necesario desarrollar un nuevo modelo de intercambiador enterrado, capaz de predecir el comportamiento dinámico del intercambiador y suficientemente rápido como para poder ser integrado en el modelo completo de la instalación sin elevar excesivamente el coste computacional. Este modelo, llamado modelo B2G (Borehole-to-Ground) ha sido presentado y validado con datos experimentales de una instalación situada en Estocolmo, Suecia [1]. Su funcionamiento ha sido comparado con el de un modelo estándar, basado en el comportamiento en régimen permanente [2], con resultados satisfactorios. En el presente trabajo se presenta una extensión de la validación de este modelo, utilizando datos experimentales correspondientes a la instalación de la UPVLC. Para ello se realizan dos tipos de validación, usando como datos de entrada al modelo la temperatura del agua a la entrada del intercambiador y, posteriormente, la carga térmica intercambiada con el terreno. Comparando los resultados con los datos experimentales se comprueba la capacidad del modelo para predecir el comportamiento dinámico del intercambiador enterrado.Este trabajo se encuentra enmarcado en el proyecto europeo dentro del séptimo programa Marco “Advanced ground source heat pump systems for heating and cooling in Mediterranean climate” (GROUND-MED)

Experimental and modeling analysis of a ground source heat pump system

[EN] This paper presents the evaluation of the performance of a ground source heat pump system monitored plant providing heating/cooling to an office building located in the Universitat Politècnica de València in Spain. The system was designed using GLHEPRO software and it has been monitored since 2005. Once a ground source heat pump has been designed, it is important to analyze its performance along the years after its construction and check whether the design was appropriate and the simulation predictions were consistent with real experimental measurements. This paper first presents the impact of the GSHP system in the ground thermal response. The simulations obtained in GLHEPRO software will be analyzed and compared to experimental measurements. The second purpose of this work is to compare the performance simulation results of a complete ground source heat pump system model built in TRNSYS, with the experimental measurements which have been registered and collected for one cooling day. Numerical predictions and experimental results are compared and discussed.This work was supported under the European FP7 framework programme "Advanced ground source heat pump systems for heating and cooling in Mediterranean climate" (Ground-Med).Montagud Montalvá, CI.; Corberán Salvador, JM.; Ruiz Calvo, F. (2013). Experimental and modeling analysis of a ground source heat pump system. Applied Energy. 109:328-336. https://doi.org/10.1016/j.apenergy.2012.11.025S32833610

Simultaneous imaging of hard and soft biological tissues in a low-field dental MRI scanner

[EN] Magnetic Resonance Imaging (MRI) of hard biological tissues is challenging due to the fleeting lifetime and low strength of their response to resonant stimuli, especially at low magnetic fields. Consequently, the impact of MRI on some medical applications, such as dentistry, continues to be limited. Here, we present three-dimensional reconstructions of ex-vivo human teeth, as well as a rabbit head and part of a cow femur, all obtained at a field strength of 260 mT. These images are the first featuring soft and hard tissues simultaneously at sub-Tesla fields, and they have been acquired in a home-made, special-purpose, pre-medical MRI scanner designed with the goal of demonstrating dental imaging at low field settings. We encode spatial information with two pulse sequences: Pointwise-Encoding Time reduction with Radial Acquisition and a new sequence we have called Double Radial Non-Stop Spin Echo, which we find to perform better than the former. For image reconstruction we employ Algebraic Reconstruction Techniques (ART) as well as standard Fourier methods. An analysis of the resulting images shows that ART reconstructions exhibit a higher signal-to-noise ratio with a more homogeneous noise distribution.We thank anonymous donors for their tooth samples, Andrew Webb and Thomas O'Reilly (LUMC) for discussions on hardware and pulse sequences, and Antonio Tristan (UVa) for information on reconstruction techniques. This work was supported by the European Commission under Grants 737180 (FET-OPEN: HISTO-MRI) and 481 (ATTRACT: DentMRI). Action co-financed by the European Union through the Programa Operativo del Fondo Europeo de Desarrollo Regional (FEDER) of the Comunitat Valenciana 2014-2020 (IDIFEDER/2018/022). Santiago Aja-Fernandez acknowledges Ministerio de Ciencia e Innovacion of Spain for research grant RTI2018-094569-B-I00.Algarín-Guisado, JM.; Díaz-Caballero, E.; Borreguero-Morata, J.; Galve, F.; Grau-Ruiz, D.; Rigla, JP.; Bosch-Esteve, R.... (2020). Simultaneous imaging of hard and soft biological tissues in a low-field dental MRI scanner. Scientific Reports. 10(1):1-14. https://doi.org/10.1038/s41598-020-78456-2S114101Haacke, E. M. et al. Magnetic Resonance Imaging: Physical Principles and Sequence Design Vol. 82 (Wiley-liss, New York, 1999).Bercovich, E. & Javitt, M. C. Medical imaging: from roentgen to the digital revolution, and beyond. Rambam Maimonides Med. J. 9, e0034. https://doi.org/10.5041/rmmj.10355 (2018).Mastrogiacomo, S., Dou, W., Jansen, J. A. & Walboomers, X. F. Magnetic resonance imaging of hard tissues and hard tissue engineered bio-substitutes. Mol. Imag. Biol. 21, 1003–1019. https://doi.org/10.1007/s11307-019-01345-2 (2019).Duer, M. J. 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Selective meta-C-H bond activation of substituted 1,3-chlorobenzenes promoted by an osmium pyridyl complex

Ethylene displaces both the acetone and phosphine ligands of [OsTp{κ1C-HNC5H3Me}(κ1- OCMe2)(PiPr3)]BF4 (2; Tp = hydrydotris(pyrazolyl)borate). The reaction takes place by stages. Initially the replacement of acetone gives the mono(olefin) derivative [OsTp{κ 1-C-[HNC5H3Me]}(η2-CH 2=CH2)(PiPr3)]BF4 (3). The substitution of the phosphine occurs at 120 °C and leads to the bis(olefin) complex [OsTp{κ1-C[HNC5H 3Me]}(η2-CH2=CH2) 2]BF4 (4). The NH wingtip of 3 and 4 undergoes deprotonation with tert-butoxide to afford the corresponding pyridyl compounds [OsTp{κ1-C[NC5H3Me]}(η2- CH2=CH2)(PiPr3)] (5) and [OsTp{κ1-C[NC5H3Me]}(η2- CH2=CH2)2] (6). At 60 °C, the solvents chloro-3-fluorobenzene, 1,3-dichlorobenzene, and 3-chlorotoluene displace the pyridyl ligand of 6 to yield the haloaryl derivatives [OsTp(3,5-C 6H3ClX)(η2-CH2=CH 2)2] (X = F (7), Cl (8), Me (9)) as a result of the selective meta-C-H bond activation of the haloarenes. © 2014 American Chemical Society.Financial support from the Spanish MINECO (Projects CTQ2011-23459 and Consolider Ingenio 2010 (CSD2007-00006)), the DGA (E35), and the European Social Fund (FSE) is acknowledged.Peer Reviewe