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Huth V.,CIDAUT Foundation | Biral F.,University of Trento | Martin O.,CIDAUT Foundation | Lot R.,University of Padua
Accident Analysis and Prevention | Year: 2012

Curve crashes are a particular matter of concern regarding motorcycle riding safety. For this reason, an intelligent Curve Warning system has been designed that gives the riders support when negotiating a curve. The system has been tested in a simulator study carried out with 20 test riders. The subjects performed three rides: one without the system (baseline) and two experimental rides using a version of the Curve Warning system, one providing the warnings by a force feedback throttle and one by a haptic glove. The effects of the two system versions were evaluated both in terms of the simulated riding performance and the subjective assessment by the riders. A descriptive analysis of the riders' reactions to the warnings shows that the warnings provided by both system versions provoke an earlier and stronger adaptation of the motorcycle dynamics to the curve than when the riders do not use the system. Riding with the Curve Warning system with the haptic glove furthermore leads to a reduction of critical curve events. The riders' subjective workload level was not affected by the system use, whereas the Curve Warning system with the force feedback throttle required an increased attention. The comparison of the riders' opinions about the system reveals a preference of the Curve Warning system with the haptic glove. The better acceptance of this system version suggests a higher potential in the enhancement of riding safety. © 2011 Elsevier Ltd.


Gardel P.,National University of Asunción | Morinigo-Sotelo D.,University of Valladolid | Morinigo-Sotelo D.,CIDAUT Foundation | Duque-Perez O.,University of Valladolid | And 3 more authors.
Proceedings - 2012 20th International Conference on Electrical Machines, ICEM 2012 | Year: 2012

The induction motor is the most widely used in industry, covering approximately 85% of the total electric loads. As an unpredicted shutdown can be very costly, early detection and diagnosis of electric motors faults yields to economical losses reduction and operational efficiency improvement. Neural networks have been proposed to solve the induction motor broken bar detection and diagnosis problem. Current spectrum data are generally used but some statistical features of time domain data have also been considered. In this paper, a performance comparison of both types of incoming data for the neural network is accomplished. © 2012 IEEE.


Cordero R.,Cidaut Foundation | Aversano M.,Piaggio
16th European Conference on Composite Materials, ECCM 2014 | Year: 2014

An introduction to the EU funded research project WASIS (Wafer design Approach for Safety Increasing in worst case Situations and joints minimizing) is given in this paper, including work performed and results obtained by the whole project consortium. Development of a wafer like structure designed as a fiber reinforced lattice composite is accomplished, aiming to replace a conventional metallic fuselage section of a small airplane with an alternative Carbon Fiber Reinforced Plastic (CFRP). WASIS project aims to achieve the challenge of "More Affordable, Safer, Cleaner and Quieter" aircrafts, developing a composite fuselage structure based on the lattice stiffening concept and optimizing geometrical and mass properties of transition zones of fuselage structural joints. Main project activities covered the full scale fuselage section design based on downscaled prototypes, as well as setting up manufacturing processes for two alternative methods; filament winding and tape placement. Analytical and numerical calculations guide the development process, and are validated through dedicated tests before leading to the final fuselage section design. Besides low weight and automatic manufacturing aspects, safety is a main concern during design, accounting for composite structure performance under several impact load cases. Special attention is given to vibroacoustic performance of test panels and fuselage section, with a dedicated study to virtually assess the acoustic field inside the composite fuselage section under operational conditions.


Duque-Perez O.,University of Valladolid | Morinigo-Sotelo D.,University of Valladolid | Morinigo-Sotelo D.,CIDAUT Foundation | Perez-Alonso M.,University of Valladolid
International Review on Modelling and Simulations | Year: 2012

Induction motors fed by Voltage Source Inverters are widely used nowadays in railway locomotives. Detection of faults in induction motors based on spectral analysis of line current is a well-known technique in the case of sinusoidal supply, but the use of inverters makes necessary to modify the existing fault detection methods. In this paper, it is analysed the influence of broken bars on line current spectra and propose a formulation for the calculation of the characteristic fault frequencies. Next, it is experimentally verified this formulation with tests of locomotive motor drives fed by a six-step converter. The proposed technique can be used on-line, providing early detection of faults avoiding catastrophic consequences and is specially adapted for the maintenance personnel, since a fault condition is detected observing the spectra. So it is not necessary to perform precise measures or further spectral analysis. © 2012 Praise Worthy Prize S.r.l. - All rights reserved.


Reyes M.,University of Valladolid | Tinaut F.V.,University of Valladolid | Gimenez B.,University of Valladolid | Perez A.,CIDAUT Foundation
Fuel | Year: 2014

In this work a study of the influence of the fuel/air equivalence ratio and engine rotational speed on the cycle-to-cycle variations in combustion in a natural gas spark ignition engine is presented. The study considers both classic estimators of cyclic dispersion and a new one, based on the burned mass and burning rate. The engine experimental conditions were as follows: Intake pressure 0.5 bar, while fuel/air equivalence ratio was changed from 1.0 to 0.63, and engine rotational speed was varied from 1000 rpm to 2500 rpm. For each equivalence ratio and engine speed, a diagnosis model is used to process the experimentally obtained combustion pressure data in order to provide combustion relevant results such as the mass burning rate at a cycle level. A procedure based on the use of genetic algorithms is used to obtain a very accurate and objective (without human intervention) adjustment of the optimum parameters needed for combustion diagnosis: angular positioning and pressure offset of the pressure register, dynamic compression ratio, and heat transfer coefficients. The model allows making the diagnosis of series of 830 consecutive engine cycles in an automatic way, increasing the objectivity of the combustion diagnosis. The paper focuses on using the values of the mass fraction burned computed from the pressure register and especially on the analysis of the combustion cycle to cycle variation in the natural gas fuelled engine. A new indicator for the study of cycle-to-cycle variations is proposed, i.e. the standard deviation of the mass fraction burning rate. The values of this new indicator are compared with other classic indicators, showing the same general trends. However, a deeper insight is provided on the combustion cyclic variation when the values of the new indicator are plotted as a function of the mass fraction burned, since this allows analyzing the cyclic variation along the combustion development in each cycle from a mass fraction burned of zero to one, with a relevant value at mass fraction burned of 0.5. More important is that the consideration of the dependence of the combustion variables (density, flame front surface, combustion speed) on the mass fraction burned allows ensemble averaging of all registered cycles for each value of mass fraction burned. This permits using the ensemble averaged mass fraction burning rate as an estimator of combustion speed. The analysis of the general trends of cyclic dispersion when engine speed and equivalence ratio are modified (1000, 1750 and 2500 rpm; 0.7, 0.8, 0.9 and 1.0) indicate that cycle-to-cycle variations show, as expected, a strong dependence on the engine rotational speed, increasing the variation with engine rpm. However, when the standard deviation of mass fraction burning rate is plotted as a function of mass fraction burned, there is a linear dependence on engine rpm, but only a very weak dependence on equivalence ratio. This means that the proposed estimator of cyclic dispersion is sensitive to only flow turbulent intensity and not to equivalence ratio. © 2014 Elsevier Ltd.


Reyes M.,University of Valladolid | Melgar A.,University of Valladolid | Perez A.,CIDAUT Foundation | Gimenez B.,University of Valladolid
International Journal of Hydrogen Energy | Year: 2013

A methodology is presented for studying the influence of using alternative fuels on the cycle-to-cycle variations of a spark ignition engine which has been fuelled with mixtures of natural gas and hydrogen in different proportions (0-100%). The experimental facility consists of a single-cylindrical spark ignition engine coupled to an asynchronous machine with a constant engine rotation speed of 1500 rpm. A thermodynamic combustion diagnostic model based on genetic algorithms is used to evaluate the combustion chamber pressure data experimentally obtained in the mentioned engine. The model is used to make the pressure diagnosis of series of 830 consecutive engine cycles automatically, with a high grade of objectivity of the combustion analysis, since the relevant adjustment parameters (i.e. pressure offset, effective compression ratio, top dead center angular position, heat transfer coefficients) are calculated by the genetic algorithm. Results indicate that the combustion process is dominated by the turbulence inside the combustion chamber (generated during intake and compression), showing little dependency of combustion variation on the mixture composition. This becomes more evident when relevant combustion variables are plotted versus the Mass Fraction Burned of each mixture. The only exception is the case of 100% hydrogen, due to the inherent higher laminar speed of hydrogen that causes combustion acceleration and thus turbulence generation. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Morinigo-Sotelo D.,University of Valladolid | Morinigo-Sotelo D.,CIDAUT Foundation | Garcia-Escudero L.A.,University of Valladolid | Duque-Perez O.,University of Valladolid | And 2 more authors.
IEEE Transactions on Industrial Electronics | Year: 2010

In this paper, we present the results of an ongoing investigation relating to the detection of static and dynamicccentricity in cage induction motors fed by a pulsewidth-modulation frequency converter using line-current spectral analysis. Two different motors fed by different supply sources (utility voltage and two different voltage converters at different assigned frequencies) were tested. A statistical analysis of the results obtained was carried out. These results allow us to present practical conclusions relating to the detection of mixed eccentricity. Copyright © 2010 IEEE.


Reyes M.,University of Valladolid | Tinaut F.V.,University of Valladolid | Melgar A.,University of Valladolid | Perez A.,CIDAUT Foundation
International Journal of Hydrogen Energy | Year: 2016

A study is presented of the influence of using mixtures of natural gas and hydrogen in different fractions (0, 25, 50, 75, 100%) on the combustion velocity and cycle-to-cycle variations in a spark ignition engine. The experimental facility consists of a single-cylinder spark ignition engine. The engine rotational speeds are 1000, 1750 and 2500 rpm. Fuel/air equivalence ratio was kept constant equal to 0.7 during the experiments. A two-zone thermodynamic combustion diagnosis model, based on solving the mass and energy conservation equations, is used to analyze the experimentally obtained pressure combustion chamber in the engine. The two-zone model considers a spherical flame front centred at the spark plug, and solves the intersection of the flame front with the piston, cylinder head and cylinder wall, in order to provide the values of the flame radius corresponding to the burned mass volume and the surfaces for heat to the piston and walls. An automatic procedure based on genetic algorithms is used to determine the optimum parameters needed for combustion diagnosis: Angular positioning and pressure offset of the pressure register, dynamic compression ratio, and heat transfer coefficients. The paper focuses on using the values of the burning velocity computed from the pressure register and especially on the analysis of the cycle to cycle variation in the natural gas/hydrogen fuelled engine, quantified through the standard deviation and the coefficient of variation of the burning speed. Increasing the hydrogen content in the mixture with natural gas increases its burning velocity. This effect is linear with hydrogen fraction, except for very high values of the fraction, when the effect of hydrogen dominates combustion. Additionally, and of practical importance, increasing the hydrogen fraction reduces the relative dispersion of combustion. This effect of hydrogen addition on reducing combustion variability is evident from 25% hydrogen content. © 2015 Hydrogen Energy Publications, LLC.


Alonso M.,CIDAUT Foundation | Plaza J.,CIDAUT Foundation
Advances in Transportation Studies | Year: 2010

A pre-screening testing procedure with a number of candidate Human-Machine-Interaction solutions for the concept of Safe Speed and Safe Distance was carried out in two European countries under the framework of the European Project PReVENT (PReVENTive and Active Safety Applications). In each country, two groups of about thirty persons participated in a two-phase test procedure, where a set of visual, auditory and haptic alternatives for speed information and distance warning were screened by means of applying a standard procedure. In particular, this paper addresses the evaluation performed in Spain where visual and auditory solutions were tested, presenting the methodology, results and main conclusions achieved. This research activity finally resulted in recommendations for visual and auditory feedback alternatives to build a driver support system for Safe Speed and Safe Distance within the PReVENT project.


Alonso M.,CIDAUT Foundation | Vega M.H.,CIDAUT Foundation | Martin O.,CIDAUT Foundation
Cognition, Technology and Work | Year: 2012

This paper is presenting a driver behaviour investigation conducted within the framework of ISi-PADAS (Integrated Human Modelling and Simulation to support Human Error Risk Analysis of Partially Autonomous Driver Assistance Systems) European Project under the 7th Framework Programme (FP7), running from September 2008 to September 2011. This research has been developed at an initial phase of the project to support the conception of a new driver assistance system aimed at improving longitudinal driving by means of information, warning and intervention strategies. In this research, the contribution to the system conception is based on providing a knowledge base of driver behaviour through the conduction of simulator experiments, so that driver modelling can be supported by driving performance data corresponding to specific scenarios of interest. In particular, this paper is aimed at investigating driver behaviour under different circumstances, namely, different longitudinal driving scenarios and distraction caused by a visual and a cognitive secondary task while driving. This way, visual and cognitive distraction effects on longitudinal driving can be analysed, focusing on the driving situations of interest. This paper provides a thorough description of the rationale behind the investigation and describes the methodology and procedure used for the experiments conduction. Moreover, the main results achieved through this research and how these results are linked to the modelling phase inside the ISi-PADAS project are covered within this paper. © 2011 Springer-Verlag London Limited.

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