Optimization of a low weight electronic differential for LEVs

It is presented a performance analysis of an Electronic Differential (ED) system designed for Light Electric Vehicles (LEVs). We have developed a test tricycle vehicle with one front steering wheel and two rear fixed units is a same axis with a brushless DC integrated in each of them. Each motor has an independent controller unit and a common Arduino electronic CPU based that can plan specific speeds for each wheels as curves are being traced. Different implementations of sensors (input current/torque, steering angle and speed of the wheels) are discussed related to hardware complexity, and performance obtained based on speed level requirements and slipping on the traction wheels.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Diplomacia cultural y relaciones público-privadas

El peso global de un país se mide no solo por su capacidad militar o económica, sino también por indicadores blandos y científico-culturales: exportaciones audiovisuales, difusión del idioma, compromiso con la cooperación internacional, o nivel de protección del Patrimonio. El sistema de acción cultural exterior español se articula entre el Ministerio de Asuntos Exteriores y de Cooperación y el Ministerio de Educación y Cultura; no obstante, la proyección internacional de nuestro Patrimonio resulta todavía endeble. De modo paralelo, la labor cultural que desarrollan las empresas se practica por medio de fundaciones, a través del mecenazgo privado. La irrupción de fórmulas público-privadas en materia de proyectos culturales enfocados al exterior constituye un recurso propicio para ganar en eficacia e impacto internacional, más aún en un contexto de crisis financieraThe global influence of a country is measured not only by its military or economic power, but also by its ‘soft power’ and its scientific, cultural abilities – audiovisual and language spread, commitment to international cooperation, or its heritage protection level. The cultural diplomacy system in Spain is organized by both Ministries of Foreign Affairs and Education and Culture. However, the international projection of the Spanish heritage is still weak. Private sponsors and foundations are responsible to the enterprises’ cultural commitment. In foreign cultural projects, the emergence of public-private partnerships is argued to be the best resource to gain efficiency and international impact, especially in the context of a financial crisi

Stretch and shrink flanging of AA2024-T3 sheet by single point incremental forming

Flanging is a forming process widely used to increase the sti ness of sheet parts in industrial applications such as the production of aircraft and automobile components. Flanges are usually formed by rubber forming or using a punch and a die, as these processes are fast and economical for producing a large number of parts. However, there is increasing interest in the manufacturing of anges using nonconventional processes, such as single point incremental forming (SPIF), that allow cost savings due to their exibility and low tooling. This thesis studies the manufacturing of open stretch and shrink anges of AA2024-T3 sheets by SPIF for a wide range of process parameters, including the ange principal radius, spindle speed and tool diameter. In this context, an experimental campaign was performed for each type of ange, classifying the principal modes of failure in the sheet and assessing its formability within the forming limit diagram (FLD). For stretch anging, FE modelling in combination with a theoretical framework based on Barlat's 89 anisotropic yield criterion was used to evaluate the formability in the stress triaxiality space. The fracture forming limit (FFL) obtained for proportional loading and the evolution of the anges were compared in the average stress triaxiality versus equivalent strain space, showing that this space might be the most appropriate for making failure predictions in SPIF. A geometry analysis of shrink anges obtained by SPIF was carried out to evaluate their formability in terms of their tendency to develop wrinkling. The elastic recovery in successful and failed is also studied. Finally, a new approach based on the analysis of compression stresses was proposed to predict the onset of failure in this type of ange. In this regard, it was shown that there exists a stress limit at which the anges analysed fail by wrinkling.El rebordeado de ancos es un proceso de conformado de chapa ampliamente usado en industrias como la aeron autica o la automobilistica para la fabricaci on de componentes estructurales de chapa delgada. Este tipo de proceso se suele realizar sobre metal, normalmente aplicando presion a trav es de una almohadilla de goma o directamente usando una matriz y un punz on met alicos. Estos dos m etodos tienen la ventaja de ser r apidos y rentables en la fabricaci on de grandes lotes. Sin embargo, son cada vez m as los trabajos que estudian el uso de procesos no convencionales, como el conformado incremental monopunto o SPIF (por sus siglas en ingl es), en aplicaciones tales como el rebordeado de agujeros, aprovechando as la exibilidad y el ahorro de utillaje que proporciona esta t ecnica. En este contexto, esta tesis presenta un estudio sobre el conformado incremental monopunto aplicado al rebordeado de ancos abiertos de AA2024-T3 para geometr as c oncavas y convexas. Este trabajo se centra en la evaluaci on de la conformabilidad en el diagrama l mite de conformado (FLD), teniendo en cuenta di erentes par ametros tales como el radio principal del anco, la velocidad de giro de la herramienta o el tama~no de la misma. As mismo, se han obtenido las ventanas de proceso para las dos geometr as propuestas, analizando las caracter sticas de los diferentes modos de fallo. Adem as, se ha usado un modelo num erico junto con un marco te orico basados en el criterio de plasticidad de Barlat 89 para analizar la conformabilidad de los ancos c oncavos en el espacio de la triaxialidad, mostrando que este enfoque puede ser m as adecuado para la predicci on del fallo que el basado en el analysis de deformaciones en el FLD. Por otro lado, se ha realizado un an alisis geom etrico de los ancos convexos, evaluando los efectos de la recuperaci on el astica en ancos exitosos y fallidos. Finalmente, se ha propuesto para este tipo de ancos un nuevo enfoque basado en la predicci on del fallo mediante el an alisis de las tensiones de compresi on. En este sentido, los resultados muestran que existe un l mite de compresi on en t erminos de tensiones a partir del cual este tipo de ancos falla por arrugamiento

Una nueva matriz de contabilidad social para España : la SAM 90

En este artículo presentamos una nueva matriz de contabilidad social de la economía española para 1990 (SAM-90). Nuestro punto de partida es una valoración minuciosa de la MCS-90, una matriz elaborada por un grupo de investigación del IVIE que publicó el INE en 1997. La SAM-90 subsana algunas de las inconsistencias detectadas en la MCS-90, distingue un mayor número de bienes y servicios destinados al consumo, desagrega las actividades del sector exterior en dos áreas de comercio, la Unión Europea y el Resto del mundo, y proporciona un mayor detalle de las operaciones de distribución de las AA.PP., tanto desde el punto de vista impositivo como del gasto. Por todo ello, la SAM-90 es una herramienta más fiable y versátil que la MCS-90 para analizar los efectos de las políticas públicas sobre la asignación de recursos y el bienestar en economías abierta

An automatic maintenance system for nuclear power plants instrumentation

Maintenance and testing of reactor protection systems is an important cause of unplanned reactor trips due to be commonly carried out in manual mode. The execution of surveillance procedures in this mode entails a great number of manual operations. Automated testing is the answer because it minimises test times and reduces the risk of human errors. GAMA-I is an automatic system for testing the reactor protection instrumentation which is based on VXI instrumentation cards. This system has important advantages over previous ones in terms of easiness to carry out software modifications related to configuration changes in the protection system. The system uses visual programming and the modifications can be implemented by ordinary instrumentation specialists without programming experience.The system has been developed at the Vandellos II Nuclear Power Plant by the I&C groups of Vandellos II, Tecnatom S.A. and ENWESA Servicios S.A. The representation for this project is held by the Spanish Association for the Nuclear Technologic Development (DTN). Financial support for this research was provided by the Electrical and Electronic Research Program (PIE-OCIDE) of the Spanish Ministry of Industry

Performance optimization in switched reluctance motor drives

In this paper, switched reluctance motors (SRM) are proposed as an alternative for electric power assisted steering (EPAS) applications. A prototype machine has been developed as very attractive design for a steering electric motor, both from a cost and size perspective. A fourphase 8/6 SRM drive is designed for a rack type EPAS which should provide a maximum force of 10 kN. Two-dimension finite element analysis is used to validate the design

PWM Control of a Buck Converter with an Amorphous Core Coil

Pulse-width modulation is widely used to control electronic converters. One of the most topologies used for high DC voltage/low DC voltage conversion is the Buck converter. It is obtained as a second order system with a LC filter between the switching subsystem and the load. The use of a coil with an amorphous magnetic material core instead of air core lets design converters with smaller size. If high switching frequencies are used for obtaining high quality voltage output, the value of the auto inductance L is reduced throughout the time. Then, robust controllers are needed if the accuracy of the converter response must not be affected by auto inductance and load variations. This paper presents a robust controller for a Buck converter based on a state space feedback control system combined with an additional virtual space variable which minimizes the effects of the inductance and load variations when a not-toohigh switching frequency is applied. The system exhibits a null steady-state average error response for the entire range of parameter variations. Simulation results are presented

Development of an electrochemical maltose biosensor

In this work, electrochemical maltose biosensors based on mutants of the maltose binding protein (MBP) are developed. A ruthenium II complex (Ru II ), which is covalently attached to MBP, serves as an electrochemical reporter of MBP conformational changes. Biosensors were made through direct attachment of Ru II complex modified MBP to gold electrode surfaces. The responses of some individual mutants were evaluated using square wave voltammetry. A maltose-dependent change in Faradic current and capacitance was observed. It is therefore demonstrated that biosensors using generically this family of bacterial periplasmic binding proteins (bPBP) can be made lending themselves to facile biorecognition element preparation and low cost electrochemical transduction

Using the Own Flexibility of a Climbing Robot as a Double Force Sensor

Force sensors are used when interaction tasks are carried out by robots in general, and by climbing robots in particular. If the mechanics and electronics systems are contained inside the own robot, the robot becomes portable without external control. Commercial force sensors cannot be used due to limited space and weight. By selecting the links material with appropriate stiffness and placing strain gauges on the structure, the own robot flexibility can be used such as force sensor. Thus, forces applied on the robot tip can be measured without additional external devices. Only gauges and small internal electronic converters are necessary. This paper illustrates the proposed algorithm to achieve these measurements. Additionally, experimental results are presented

Torque control of switched reluctance motors

This paper presents the performance of an instantaneous torque control method. The simulation and experimental results illustrate the capability of Switched Reluctance Motors (SRM) being used in the motor drive industry. Based on experimental data, the advantages of this control method and its disadvantages in practical implementation were studied. The model used in the simulation is the linear magnetic model which has the 12/8 structure, the same structure as the experimental switched reluctance motor