CARTIF Foundation

Boecillo, Spain

CARTIF Foundation

Boecillo, Spain
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Kontes G.D.,Technical University of Crete | Valmaseda C.,CARTIF Foundation | Giannakis G.I.,Technical University of Crete | Katsigarakis K.I.,Technical University of Crete | And 2 more authors.
Journal of Process Control | Year: 2014

The topic of optimized building operation has attracted considerable interest in the research community: in this context model-based supervisory control design approaches have been shown to yield effective/optimized operation with regards to energy performance or other related operational parameters. A hindrance towards the adoption of such methodologies is the need for a mathematical model tailored to each building which is capable of capturing all pertinent dynamics. Developing and tuning such a model can be a time-consuming and costly proposition, and is the main reason why such approaches have found little applicability beyond the research space. The utilization of models constructed in the building design phases - for the reason of estimating energy performance - properly adapted for the task at hand can be a viable methodology to overcome this problem. We present in this paper, an online process where a stochastic optimization algorithm utilizing a detailed thermal simulation model of the building along with historical sensor measurements and weather and occupancy forecasts, is used to design effective control strategies for a predefined period. A detailed description of the methodology is provided and the proposed approach is evaluated on a heating experiment conducted in a real building located in Greece. © 2014 Elsevier Ltd. All rights reserved.

Bustillo A.,University of Burgos | Correa M.,Technical University of Madrid | Renones A.,CARTIF Foundation
Sensors | Year: 2011

The installation of suitable sensors close to the tool tip on milling centres is not possible in industrial environments. It is therefore necessary to design virtual sensors for these machines to perform online fault detection in many industrial tasks. This paper presents a virtual sensor for online fault detection of multitooth tools based on a Bayesian classifier. The device that performs this task applies mathematical models that function in conjunction with physical sensors. Only two experimental variables are collected from the milling centre that performs the machining operations: the electrical power consumption of the feed drive and the time required for machining each workpiece. The task of achieving reliable signals from a milling xprocess is especially complex when multitooth tools are used, because each kind of cutting insert in the milling centre only works on each workpiece during a certain time window. Great effort has gone into designing a robust virtual sensor that can avoid re-calibration due to, e.g., maintenance operations. The virtual sensor developed as a result of this research is successfully validated under real conditions on a milling centre used for the mass production of automobile engine crankshafts. Recognition accuracy, calculated with a k-fold cross validation, had on average 0.957 of true positives and 0.986 of true negatives. Moreover, measured accuracy was 98%, which suggests that the virtual sensor correctly identifies new cases. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

Zalama E.,University of Valladolid | Gomez-Garcia-Bermejo J.,University of Valladolid | Llamas J.,CARTIF Foundation | Medina R.,CARTIF Foundation
Computer-Aided Civil and Infrastructure Engineering | Year: 2011

Abstract: Obtaining virtual models from real buildings, terrains, or building works is a matter of increased interest in construction. The application of such models ranges from technical use in architecture and civil engineering, to multimedia presentation, or remote visits through the web. This is becoming possible thanks to recent advances in laser scanning technology and related 3D processing algorithms. Moreover, real texture mapped onto 3D models is often required for communication, cataloguing, or digital documentation projects. In this article, an effective methodology to obtain digital building documentation based on 3D textured models is presented. First of all, a brief presentation of laser scanners is given as their data are used. An approach for mapping photographic images onto 3D models is also presented. The proposed approach, based on a camera registration method, offers high flexibility as it is based on hand-held cameras and can be implemented in a computing-effective way. A method for automatic image selection in overlapped areas is also presented. Finally, some hints are given concerning the automatic extraction of sections, orthophotos, and feature lines from the models. Experimental results focused on heritage buildings are shown, which demonstrate the suitability of the proposed techniques. © 2010 Computer-Aided Civil and Infrastructure Engineering.

Arnanz R.,CARTIF Foundation | Miguel L.J.,University of Valladolid | Peran J.R.,University of Valladolid | Mendoza A.,CARTIF Foundation
Control Engineering Practice | Year: 2011

The use of inverters in induction motor control has reduced classical motor faults, such as broken rotor bars or windings short-circuit, besides improving control performance. The control becomes faster and more precise, reducing peaks in current and torque, so that the motor can have a softer operation. On the other hand, new elements are included in the system and it will be necessary to take into account their faults. These elements are sensors and power electronic devices that since a control point of view are the system sensors and actuators. Fault tolerance tries to maintain the system under control in case a fault appears in the system. If this is not possible, it takes the system to a safe operational point. In this paper a fault-tolerant control for induction motors is designed. Based on a direct torque control, new control strategies have been added in case current sensor and power switch faults are detected. The challenge is to overcome these faults without any physical redundancy of sensors or power switches as other authors propose. With the proposed control, it will be possible to guarantee the motor operation in the whole speed-torque range with one or none current sensors instead of the two usually used, though the performance will be slightly worsened. In case of inverter faults, the operation range will be restricted but the performance with respect to the fault situation is improved. © 2011 Elsevier Ltd.

Medina R.,CARTIF Foundation | Gomez-Garcia-Bermejo J.,University of Valladolid | Zalama E.,CARTIF Foundation
2010 - 27th International Symposium on Automation and Robotics in Construction, ISARC 2010 | Year: 2010

Pavement maintenance requires knowing the state of the road surface. Human inspection is the most common method for evaluating this state. Recently, the automated visual inspection has been addressed, but some important questions remain open concerning the variable ambient lighting, shadows, device synchronisation and the large amount of data. In the present paper, an automated visual inspection system is presented. Images are obtained using laser lighting and linear cameras onboard a vehicle. Longitudinal and transversal cracks are detected and classified using a novel approach based on combining traditional features and Gabor filters. A Differential Global Positioning System (DGPS), a web camera and an Inertial Profiler to measure the International Roughness Index (IRI) are also considered in order to obtain comprehensive information about the road state. Implementation details are given concerning image acquisition and processing, system architecture and data synchronisation. Field results are presented which prove the suitability of the approach.

Villa L.F.,CARTIF Foundation | Renones A.,CARTIF Foundation | Peran J.R.,CARTIF Foundation | De Miguel L.J.,University of Valladolid
Mechanical Systems and Signal Processing | Year: 2011

This work presents the development of an angular resampling algorithm for applying in conditions of high speed variability, as occurs in wind turbines, and the results obtained when applied to simulated signals, bearings diagnostic test-beds and wind turbines. The results improve the accuracy of similar resampling algorithms offered by the consulted bibliography. This algorithm is part of the wind turbine diagnostic system developed by the authors. © 2010 Elsevier Ltd. All rights reserved.

Zalama E.,University of Valladolid | Gomez-Garcia-Bermejo J.,University of Valladolid | Medina R.,CARTIF Foundation | Llamas J.,CARTIF Foundation
Computer-Aided Civil and Infrastructure Engineering | Year: 2014

Pavement management systems require detailed information of the current state of the roads to take appropriate actions to optimize expenditure on maintenance and rehabilitation. In particular, the presence of cracks is a cardinal aspect to be considered. This article presents a solution based on an instrumented vehicle equipped with an imaging system, two Inertial Profilers, a Differential Global Positioning System, and a webcam. Information about the state of the road is acquired at normal road speed. A method based on the use of Gabor filters is used to detect the longitudinal and transverse cracks. The methodologies used to create Gabor filter banks and the use of the filtered images as descriptors for subsequent classifiers are discussed in detail. Three different methodologies for setting the threshold of the classifiers are also evaluated. Finally, an AdaBoost algorithm is used for selecting and combining the classifiers, thus improving the results provided by a single classifier. A large database has been acquired and used to train and test the proposed system and methods, and suitable results have been obtained in comparison with other reference works. © 2014 Computer-Aided Civil and Infrastructure Engineering 29 5 May 2014 10.1111/mice.12042 Original Article Original Articles © 2013 Computer-Aided Civil and Infrastructure Engineering.

Gomez-Garcia-Bermejo J.,University of Valladolid | Zalama E.,University of Valladolid | Feliz R.,CARTIF Foundation
Computer-Aided Civil and Infrastructure Engineering | Year: 2013

Laser range sensors are playing an increased role in construction. These devices are used to collect a large number of points from different locations and then, those points are registered in a common framework. This article describes a new procedure for the registration of point clouds, especially suited to the fields of architecture and cultural heritage. Often, in these fields, the registration of point clouds is subject to errors due to the fact that an important number of points do not lie on particular geometric features. In this article, an accurate and efficient approach for 3D data registration based on Iterative Closest Point (ICP) algorithm is proposed, which takes advantage of the color data acquired along with range data. Points suitable for registration are selected according to their local geometry and/or color properties, thus a significant improvement on performance convergence and processing time is obtained. The algorithm performs an automatic, on-the-flight estimation of the overlapping region, taking into account possible color differences produced by lighting changes through the measurement process. The proposed approach has been tested on real scanned data from cultural heritage buildings and compared to other approaches, showing a better performance in terms of automation degree, accuracy, and speed. © 2012 Computer-Aided Civil and Infrastructure Engineering.

Villa L.F.,CARTIF Foundation | Renones A.,CARTIF Foundation | Peran J.R.,CARTIF Foundation | De Miguel L.J.,University of Valladolid
Mechanical Systems and Signal Processing | Year: 2012

In this paper the authors are dealing with the detection of different mechanical faults (unbalance and misalignment) under a wide range of working conditions of speed and load. The conditions tested in a test bench are similar to the ones that can be found in different kinds of machines like for example wind turbines. The authors demonstrate how to take advantage of the information on vibrations from the mechanical system under study in a wide range of load and speed conditions. Using such information the prognosis and detection of faults is faster and more reliable than the one obtained from an analysis over a restricted range of working conditions (e.g. nominal). © 2011 Elsevier Ltd. All rights reserved.

Marcos S.,CARTIF Foundation | Gomez-Garcia-Bermejo J.,University of Valladolid | Zalama E.,University of Valladolid
Interacting with Computers | Year: 2010

In this paper an interactive and realistic virtual head oriented to human-computer interaction and social robotics is presented. It has been designed following a hybrid approach, taking robotic characteristics into account and searching for a convergence between these characteristics, real facial actions and animation techniques. An initial head model is first obtained from a real person using a laser scanner. Then the model is animated using a hierarchical skeleton based procedure. The proposed rig structure is close to real facial muscular anatomy and its behaviour follows the Facial Action Coding System. Speech synthesis and visual human-face tracking capabilities are also integrated for providing the head with further interaction ability. Using the said hybrid approach, the head can be readily linked to a social-robot architecture. The opinions of a number of persons interacting with this social avatar have been evaluated and are reported in the paper, as against their reactions when interacting with a social robot with a mechatronic face. Results show the suitability of the avatar for on-screen, real-time interfacing in human-computer interaction. The proposed technique could also be helpful in the future for designing and parameterizing mechatronic human-like heads for social robots. © 2009 Elsevier B.V. All rights reserved.

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