Escuela Tecnica Superior de Ingenieria de Bilbao

Bilbao, Spain

Escuela Tecnica Superior de Ingenieria de Bilbao

Bilbao, Spain
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Olvera D.,Escuela Tecnica Superior de Ingenieria de Bilbao | Lopez De Lacalle L.N.,Escuela Tecnica Superior de Ingenieria de Bilbao | Compean F.I.,Technological Institute of Nuevo Leon | Fz-Valdivielso A.,Escuela Tecnica Superior de Ingenieria de Bilbao | And 2 more authors.
International Journal of Advanced Manufacturing Technology | Year: 2012

Modern industry requires high-precision machines and processes. This requirement implies the determination and reduction of all possible sources of error. For turning, a main error is related to machine-tool- workpiece deformation caused by cutting force. On the other hand, current turning centers are structurally more complicated than conventional lathes. However, stiffness values for this kind of machine are not described yet in literature. Thus, the aim of this work is to provide stiffness values for this type of machines clamping a common workpiece. To obtain this information an experimental methodology to measure static stiffness along kinematic chain of the turning center is proposed. The method may be useful for both users and machine manufacturers in order to consider this factor in the general error budget of the turning process. At the same time, stiffness values for lathes with a Y-axis incorporated in a three-axis turret and equipped with living tools are registered. © 2011 Springer-Verlag.


Morillo A.,Escuela Tecnica Superior de Ingenieria de Bilbao | Astarloa A.,Escuela Tecnica Superior de Ingenieria de Bilbao | Lazaro J.,Escuela Tecnica Superior de Ingenieria de Bilbao | Bidarte U.,Escuela Tecnica Superior de Ingenieria de Bilbao | Jimenez J.,Escuela Tecnica Superior de Ingenieria de Bilbao
2010 International Conference on Applied Electronics, AE 2010 | Year: 2010

The need of critical applications has derived in the development of several techniques that aim to guarantee system operability. The vast majority of these systems own a microprocessor to control its functionality. Thus, system reliability largely depends on the proper function of the microprocessor. This article presents a state of the art in the techniques for reliable microprocessor architectures for FPGAs. One of this techniques, Triple Modular Redundancy (TMR) combined with Dynamic Partial Reconfiguration (DPR), allows the development of coarse grain modularity architectures where the redundant module is the soft-core microprocessor. However, its main lack is a suitable synchronization method for the faulty module. This paper shows the trends on synchronization methods and proposes the use of an Autonomous Fault Tolerant System (AFTS) for developing a more suitable synchronization method.


Gutierrez J.J.,Escuela Tecnica Superior de Ingenieria de Bilbao | Saiz P.,Escuela Tecnica Superior de Ingenieria de Bilbao | Lazkano A.,Escuela Tecnica Superior de Ingenieria de Bilbao | Ruiz J.,Escuela Tecnica Superior de Ingenieria de Bilbao | And 2 more authors.
Green Energy and Technology | Year: 2012

In the last years the use of wind farms has drastically increased. The question is how those new generation systems will affect to the whole grid. In principle, wind energy can be considered a risky source in terms of power quality that must be certified on the basis of measurements performed according to international standards and guidelines. The IEC 61400-21 standard is the reference normative for the certification of the power quality of wind turbines. The first edition was published in 2001 and it specifies the main relevant features of power quality that should be measured in a wind turbine as well as the procedures for their measurement and assessment. According to it, measurements should be performed for harmonic content, flicker, voltage drops as well as active and reactive power, during normal and switching operations. Among those disturbances, flicker has the most complex and sensitive testing procedure. Power fluctuations of the wind turbine generate voltage fluctuations causing changes in the luminous flux from light sources. Such changes may produce a very unpleasant visual sensation, known as flicker, leading to complaints from utility customers. The IEC 61000-4-15 standard describes the functional specifications of a flicker measurement device and provides a short-term indicator, Pst; to characterize the discomfort. This chapter demonstrates the sensitivity of the procedure defined by the IEC 61400-21 standard to asses the flicker by means of different signal processing techniques.


Lazaro I.,Escuela Tecnica Superior de Ingenieria de Bilbao | Murroni M.,Escuela Tecnica Superior de Ingenieria de Bilbao | Redondo I.,Escuela Tecnica Superior de Ingenieria de Bilbao | Sanchez M.,Escuela Tecnica Superior de Ingenieria de Bilbao | Velez M.,Escuela Tecnica Superior de Ingenieria de Bilbao
Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering | Year: 2012

Cognitive Radio Systems have been proposed as the solution to spectrum scarcity, and Spectrum Sensing a good way to detect which frequencies are being used by primary users and avoid interferences. When primary signals are unknown, energy detection is the best while easiest technique for the sensing process. In this paper, we consider energy detection based spectrum sensing for narrowband signals in the TV wideband. Simulations are performed to obtain ROC curves. Designed detector has been validated both with signals generated in the laboratory and with real signals captured from the radio space. © 2012 ICST Institute for Computer Science, Social Informatics and Telecommunications Engineering.

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