Determining electric vehicle charging point locations considering drivers' daily activities

In this paper the daily temporal and spatial behavior of electric vehicles (EVs) is modelled using an activity-based (ActBM) microsimulation model for Flanders region (Belgium). Assuming that all EVs are completely charged at the beginning of the day, this mobility model is used to determine the percentage of Flemish vehicles that cannot cover their programmed daily trips and need to be recharged during the day. Assuming a variable electricity price, an optimization algorithm determines when and where EVs can be recharged at minimum cost for their owners. This optimization takes into account the individual mobility constraint for each vehicle, as they can only be charged when the car is stopped and the owner is performing an activity. From this information, the aggregated electric demand for Flanders is obtained, identifying the most overloaded areas at the critical hours. Finally it is also analyzed what activities EV owners are underway during their recharging period. From this analysis, different actions for public charging point deployment in different areas and for different activities are proposed.

A study of feature combination for vehicle detection based on image processing

Video analytics play a critical role in most recent traffic monitoring and driver assistance systems. In this context, the correct detection and classification of surrounding vehicles through image analysis has been the focus of extensive research in the last years. Most of the pieces of work reported for image-based vehicle verification make use of supervised classification approaches and resort to techniques, such as histograms of oriented gradients (HOG), principal component analysis (PCA), and Gabor filters, among others. Unfortunately, existing approaches are lacking in two respects: first, comparison between methods using a common body of work has not been addressed; second, no study of the combination potentiality of popular features for vehicle classification has been reported. In this study the performance of the different techniques is first reviewed and compared using a common public database. Then, the combination capabilities of these techniques are explored and a methodology is presented for the fusion of classifiers built upon them, taking into account also the vehicle pose. The study unveils the limitations of single-feature based classification and makes clear that fusion of classifiers is highly beneficial for vehicle verification.

Histograms of oriented gradients for fast on-board vehicle verification

Histograms of Oriented Gradients (HoGs) provide excellent results in object detection and verification. However, their demanding processing requirements bound their applicability in some critical real-time scenarios, such as for video-based on-board vehicle detection systems. In this work, an efficient HOG configuration for pose-based on-board vehicle verification is proposed, which alleviates both the processing requirements and required feature vector length without reducing classification performance. The impact on classification of some critical configuration and processing parameters is in depth analyzed to propose a baseline efficient descriptor. Based on the analysis of its cells contribution to classification, new view-dependent cell-configuration patterns are proposed, resulting in reduced descriptors which provide an excellent balance between performance and computational requirements, rendering higher verification rates than other works in the literature.

Optimized HOG for on-road video based vehicle verification

Vision-based object detection from a moving platform becomes particularly challenging in the field of advanced driver assistance systems (ADAS). In this context, onboard vision-based vehicle verification strategies become critical, facing challenges derived from the variability of vehicles appearance, illumination, and vehicle speed. In this paper, an optimized HOG configuration for onboard vehicle verification is proposed which not only considers its spatial and orientation resolution, but descriptor processing strategies and classification. An in-depth analysis of the optimal settings for HOG for onboard vehicle verification is presented, in the context of SVM classification with different kernels. In contrast to many existing approaches, the evaluation is realized in a public and heterogeneous database of vehicle and non-vehicle images in different areas of the road, rendering excellent verification rates that outperform other similar approaches in the literature.

Analysis of air flow past and through the 2415-3S airfoil for an unmanned aerial vehicle with internal propulsion system

This paper deals with the prediction of velocity fields on the 2415-3S airfoil which will be used for an unmanned aerial vehicle with internal propulsion system and in this way analyze the air flow through an internal duct of the airfoil using computational fluid dynamics. The main objective is to evaluate the effect of the internal air flow past the airfoil and how this affects the aerodynamic performance by means of lift and drag forces. For this purpose, three different designs of the internal duct were studied; starting from the base 2415-3S airfoil developed in previous investigation, basing on the hypothesis of decreasing the flow separation produced when the propulsive airflow merges the external flow, and in this way obtaining the best configuration. For that purpose, an exhaustive study of the mesh sensitivity was performed. It was used a non-structured mesh since the computational domain is three-dimensional and complex. The selected mesh contains approximately 12.5 million elements. Both the computational domain and the numerical solution were made with commercial CAD and CFD software, respectively. Air, incompressible and steady was analyzed. The boundary conditions are in concordance with experimental setup in the AF 6109 wind tunnel. The k-e model is utilized to describe the turbulent flow process as followed in references. Results allowed obtaining velocity contours as well as lift and drag coefficients and also the location of separation and reattachment regions in some cases for zero degrees of angle of attack on the internal and external surfaces of the airfoil. Finally, the selection of the configuration with the best aerodynamic performance was made, selecting the option without curved baffles.

Numerical analysis of air flow past the 2415-3S airfoil for an unmanned aerial vehicle with internal propulsion system

This paper deals with the prediction of pressure and velocity fields on the 2415-3S airfoil which will be used for and unmanned aerial vehicle with internal propulsion system and in this way analyze the air flow through an internal duct of the airfoil using computational fluid dynamics. The main objective is to evaluate the effect of the internal air flow past the airfoil and how this affects the aerodynamic performance by means of lift and drag forces. For this purpose, three different designs of the internal duct were studied; starting from the base 2415-3S airfoil developed in previous investigation, basing on the hypothesis of decreasing the flow separation produced when the propulsive airflow merges the external flow, and in this way obtaining the best configuration. For that purpose, an exhaustive study of the mesh sensitivity was performed. It was used a non-structured mesh since the computational domain is tridimensional and complex. The selected mesh contains approximately 12.5 million elements. Both the computational domain and the numerical solution were made with commercial CAD and CFD software respectively. Air, incompressible and steady was analyzed. The boundary conditions are in concordance with experimental setup in the AF 6109 wind tunnel. The k-ε model is utilized to describe the turbulent flow process as followed in references. Results allowed obtaining pressure and velocity contours as well as lift and drag coefficients and also the location of separation and reattachment regions in some cases for zero degrees of angle of attack on the internal and external surfaces of the airfoil. Finally, the selection of the configuration with the best aerodynamic performance was made, selecting the option without curved baffles.

Co-simulation Methodologies for Hybrid and Electric Vehicle Dynamics

In recent decades, full electric and hybrid electric vehicles have emerged as an alternative to conventional cars due to a range of factors, including environmental and economic aspects. These vehicles are the result of considerable efforts to seek ways of reducing the use of fossil fuel for vehicle propulsion. Sophisticated technologies such as hybrid and electric powertrains require careful study and optimization. Mathematical models play a key role at this point. Currently, many advanced mathematical analysis tools, as well as computer applications have been built for vehicle simulation purposes. Given the great interest of hybrid and electric powertrains, along with the increasing importance of reliable computer-based models, the author decided to integrate both aspects in the research purpose of this work. Furthermore, this is one of the first final degree projects held at the ETSII (Higher Technical School of Industrial Engineers) that covers the study of hybrid and electric propulsion systems. The present project is based on MBS3D 2.0, a specialized software for the dynamic simulation of multibody systems developed at the UPM Institute of Automobile Research (INSIA). Automobiles are a clear example of complex multibody systems, which are present in nearly every field of engineering. The work presented here benefits from the availability of MBS3D software. This program has proven to be a very efficient tool, with a highly developed underlying mathematical formulation. On this basis, the focus of this project is the extension of MBS3D features in order to be able to perform dynamic simulations of hybrid and electric vehicle models. This requires the joint simulation of the mechanical model of the vehicle, together with the model of the hybrid or electric powertrain. These sub-models belong to completely different physical domains. In fact the powertrain consists of energy storage systems, electrical machines and power electronics, connected to purely mechanical components (wheels, suspension, transmission, clutch…). The challenge today is to create a global vehicle model that is valid for computer simulation. Therefore, the main goal of this project is to apply co-simulation methodologies to a comprehensive model of an electric vehicle, where sub-models from different areas of engineering are coupled. The created electric vehicle (EV) model consists of a separately excited DC electric motor, a Li-ion battery pack, a DC/DC chopper converter and a multibody vehicle model. Co-simulation techniques allow car designers to simulate complex vehicle architectures and behaviors, which are usually difficult to implement in a real environment due to safety and/or economic reasons. In addition, multi-domain computational models help to detect the effects of different driving patterns and parameters and improve the models in a fast and effective way. Automotive designers can greatly benefit from a multidisciplinary approach of new hybrid and electric vehicles. In this case, the global electric vehicle model includes an electrical subsystem and a mechanical subsystem. The electrical subsystem consists of three basic components: electric motor, battery pack and power converter. A modular representation is used for building the dynamic model of the vehicle drivetrain. This means that every component of the drivetrain (submodule) is modeled separately and has its own general dynamic model, with clearly defined inputs and outputs. Then, all the particular submodules are assembled according to the drivetrain configuration and, in this way, the power flow across the components is completely determined. Dynamic models of electrical components are often based on equivalent circuits, where Kirchhoff’s voltage and current laws are applied to draw the algebraic and differential equations. Here, Randles circuit is used for dynamic modeling of the battery and the electric motor is modeled through the analysis of the equivalent circuit of a separately excited DC motor, where the power converter is included. The mechanical subsystem is defined by MBS3D equations. These equations consider the position, velocity and acceleration of all the bodies comprising the vehicle multibody system. MBS3D 2.0 is entirely written in MATLAB and the structure of the program has been thoroughly studied and understood by the author. MBS3D software is adapted according to the requirements of the applied co-simulation method. Some of the core functions are modified, such as integrator and graphics, and several auxiliary functions are added in order to compute the mathematical model of the electrical components. By coupling and co-simulating both subsystems, it is possible to evaluate the dynamic interaction among all the components of the drivetrain. ‘Tight-coupling’ method is used to cosimulate the sub-models. This approach integrates all subsystems simultaneously and the results of the integration are exchanged by function-call. This means that the integration is done jointly for the mechanical and the electrical subsystem, under a single integrator and then, the speed of integration is determined by the slower subsystem. Simulations are then used to show the performance of the developed EV model. However, this project focuses more on the validation of the computational and mathematical tool for electric and hybrid vehicle simulation. For this purpose, a detailed study and comparison of different integrators within the MATLAB environment is done. Consequently, the main efforts are directed towards the implementation of co-simulation techniques in MBS3D software. In this regard, it is not intended to create an extremely precise EV model in terms of real vehicle performance, although an acceptable level of accuracy is achieved. The gap between the EV model and the real system is filled, in a way, by introducing the gas and brake pedals input, which reflects the actual driver behavior. This input is included directly in the differential equations of the model, and determines the amount of current provided to the electric motor. For a separately excited DC motor, the rotor current is proportional to the traction torque delivered to the car wheels. Therefore, as it occurs in the case of real vehicle models, the propulsion torque in the mathematical model is controlled through acceleration and brake pedal commands. The designed transmission system also includes a reduction gear that adapts the torque coming for the motor drive and transfers it. The main contribution of this project is, therefore, the implementation of a new calculation path for the wheel torques, based on performance characteristics and outputs of the electric powertrain model. Originally, the wheel traction and braking torques were input to MBS3D through a vector directly computed by the user in a MATLAB script. Now, they are calculated as a function of the motor current which, in turn, depends on the current provided by the battery pack across the DC/DC chopper converter. The motor and battery currents and voltages are the solutions of the electrical ODE (Ordinary Differential Equation) system coupled to the multibody system. Simultaneously, the outputs of MBS3D model are the position, velocity and acceleration of the vehicle at all times. The motor shaft speed is computed from the output vehicle speed considering the wheel radius, the gear reduction ratio and the transmission efficiency. This motor shaft speed, somehow available from MBS3D model, is then introduced in the differential equations corresponding to the electrical subsystem. In this way, MBS3D and the electrical powertrain model are interconnected and both subsystems exchange values resulting as expected with tight-coupling approach.When programming mathematical models of complex systems, code optimization is a key step in the process. A way to improve the overall performance of the integration, making use of C/C++ as an alternative programming language, is described and implemented. Although this entails a higher computational burden, it leads to important advantages regarding cosimulation speed and stability. In order to do this, it is necessary to integrate MATLAB with another integrated development environment (IDE), where C/C++ code can be generated and executed. In this project, C/C++ files are programmed in Microsoft Visual Studio and the interface between both IDEs is created by building C/C++ MEX file functions. These programs contain functions or subroutines that can be dynamically linked and executed from MATLAB. This process achieves reductions in simulation time up to two orders of magnitude. The tests performed with different integrators, also reveal the stiff character of the differential equations corresponding to the electrical subsystem, and allow the improvement of the cosimulation process. When varying the parameters of the integration and/or the initial conditions of the problem, the solutions of the system of equations show better dynamic response and stability, depending on the integrator used. Several integrators, with variable and non-variable step-size, and for stiff and non-stiff problems are applied to the coupled ODE system. Then, the results are analyzed, compared and discussed. From all the above, the project can be divided into four main parts: 1. Creation of the equation-based electric vehicle model; 2. Programming, simulation and adjustment of the electric vehicle model; 3. Application of co-simulation methodologies to MBS3D and the electric powertrain subsystem; and 4. Code optimization and study of different integrators. Additionally, in order to deeply understand the context of the project, the first chapters include an introduction to basic vehicle dynamics, current classification of hybrid and electric vehicles and an explanation of the involved technologies such as brake energy regeneration, electric and non-electric propulsion systems for EVs and HEVs (hybrid electric vehicles) and their control strategies. Later, the problem of dynamic modeling of hybrid and electric vehicles is discussed. The integrated development environment and the simulation tool are also briefly described. The core chapters include an explanation of the major co-simulation methodologies and how they have been programmed and applied to the electric powertrain model together with the multibody system dynamic model. Finally, the last chapters summarize the main results and conclusions of the project and propose further research topics. In conclusion, co-simulation methodologies are applicable within the integrated development environments MATLAB and Visual Studio, and the simulation tool MBS3D 2.0, where equation-based models of multidisciplinary subsystems, consisting of mechanical and electrical components, are coupled and integrated in a very efficient way.

Aeroelastic effects in a traffic sign panel induced by a passing vehicle

Here, a simple theoretical model of the vehicle induced flow and its effects on traffic sign panels is presented. The model is a continuation of a previous one by Sanz-Andrés and coworkers, now including the flexibility of the panel (and, therefore, the flow effects associated to the motion of the panel). Through the paper an aeroelastic one-degree-of-freedom model is developed and the flow effects are computed from unsteady potential theory. The influence of panel's mechanical properties (mass, damping ratio, and stiffness) in the motion induced forces are numerically analyzed.

Vehicle induced loads on pedestrian barriers

This paper is a continuation of a previous one, Sanz-Andrés, Santiago-Prowald, Baker and Quinn (J. Wind Eng. Ind. Aerodyn. 91 (2003) 925) concerning the loads generated on a structural panel (traffic sign) by vehicle running along the road, although obviously, the results are also applicable to the effects of other moving vehicles such as trains. The structural panel was modelized as a large plate whose largest dimension is perpendicular to the vehicle motion direction. In this paper a similar approach is used to develop a mathematical model for the vehicle-induced load on pedestrian barriers, modelized as a large plate whose largest dimension is parallel to the vehicle motion direction. The purpose of the work is to develop a model simple enough to give analytical results, although with the physical phenomena correctly accounted for, such as to be able to explain, at least qualitatively, the main characteristics of the phenomenon, as observed in the experiments performed by Quinn et al. (J. Wind Eng. Ind. Aerodyn. 89 (2001) 831). Actually, in spite of the model simplicity, results of the theoretical model show a reasonable good quantitative agreement with the experimental results. The aim of this and previous publications is to provide to the transport infrastructure community with some simple tools that can help to explain, and in some cases also to compute, the unsteady loading produced by moving vehicles on persons and installations placed close to the roads or tracks.

Vehicle-induced force on pedestrians

The main object of this study is to contribute to the study of the train-induced force on pedestrians with a theoretical model based on unsteady potential flow. The same method can be applied to other bodies and other kind of moving vehicles. The outcome of this theoretical model is that the force coefficient (referred to the vehicle speed and the pedestrian cross-section diameter) acting on the pedestrian are proportional to a single parameter which involves the pedestrian cross-section diameter, the vehicle cross-section area and the distance between the pedestrian and the vehicle. The results of the present model concerning the change in modulus and orientation experienced by the pedestrian, as the vehicles pass by, has a similar appearance to that considered in the European standards. The results obtained are mainly qualitative because of the simplifying assumptions needed to obtain a simple formulation leading to analytical results, except in the case of a vehicle with streamlined front shapes, where quantitative results can be expected.

Vehicle-induced loads on traffic sign panels

The determination of the loads on traffic sign panels in the current standards does not, in general, take into account the vehicle-induced loads, as explained by Quinn, Baker and Wright (QBW in what follows) (J. Wind Eng. Ind. Aerodyn. 89 (2001) 831). On the other hand, a report from Cali and Covert (CC) (J. Wind Eng. Ind. Aerodyn. 84 (2000) 87) indicates that in highway sign support structures, vehicle-induced loads have led to premature failures in some cases. The aim of this paper is to present a mathematical model for the vehicle-induced load on a flat sign panel, simple enough to give analytical results, but able to explain the main characteristics of the phenomenon. The results of the theoretical model help to explain the behaviour observed in the experiments performed in previous studies.

Telemetría de vehículos FSAE con microcontrolador PIC32 y transceptor de radio CC1101

Quizás el campo de las telecomunicaciones sea uno de los campos en el que más se ha progresado en este último siglo y medio, con la ayuda de otros campos de la ciencia y la técnica tales como la computación, la física electrónica, y un gran número de disciplinas, que se han utilizado estos últimos 150 años en conjunción para mejorarse unas con la ayuda de otras. Por ejemplo, la química ayuda a comprender y mejorar campos como la medicina, que también a su vez se ve mejorada por los progresos en la electrónica creados por los físicos y químicos, que poseen herramientas más potentes para calcular y simular debido a los progresos computacionales. Otro de los campos que ha sufrido un gran avance en este último siglo es el de la automoción, aunque estancados en el motor de combustión, los vehículos han sufrido enormes cambios debido a la irrupción de los avances en la electrónica del automóvil con multitud de sistemas ya ampliamente integrados en los vehículos actuales. La Formula SAE® o Formula Student es una competición de diseño, organizada por la SAE International (Society of Automotive Engineers) para estudiantes de universidades de todo el mundo que promueve la ingeniería a través de una competición donde los miembros del equipo diseñan, construyen, desarrollan y compiten en un pequeño y potente monoplaza. En el ámbito educativo, evitando el sistema tradicional de clases magistrales, se introducen cambios en las metodologías de enseñanza y surge el proyecto de la Fórmula Student para lograr una mejora en las acciones formativas, que permitan ir incorporando nuevos objetivos y diseñar nuevas situaciones de aprendizaje que supongan una oportunidad para el desarrollo de competencias de los alumnos, mejorar su formación como ingenieros y contrastar sus progresos compitiendo con las mejores universidades del mundo. En este proyecto se pretende dotar a los alumnos de las escuelas de ingeniería de la UPM que desarrollan el vehículo de FSAE de una herramienta de telemetría con la que evaluar y probar comportamiento del vehículo de FSAE junto con sus subsistemas que ellos mismos diseñan, con el objetivo de evaluar el comportamiento, introducir mejoras, analizar resultados de una manera más rápida y cómoda, con el objetivo de poder progresar más rápidamente en su desarrollo, recibiendo y almacenando una realimentación directa e instantánea del funcionamiento mediante la lectura de los datos que circulan por el bus CAN del vehículo. También ofrece la posibilidad de inyectar datos a los sistemas conectados al bus CAN de manera remota. Se engloba en el conjunto de proyectos de la FSAE, más concretamente en los basados en la plataforma PIC32 y propone una solución conjunta con otros proyectos o también por sí sola. Para la ejecución del proyecto se fabricó una placa compuesta de dos placas de circuito impreso, la de la estación base que envía comandos, instrucciones y datos para inyectar en el bus CAN del vehículo mediante radiofrecuencia y la placa que incorpora el vehículo que envía las tramas que circulan por el bus CAN del vehículo con los identificadores deseados, ejecuta los comandos recibidos por radiofrecuencia y salva las tramas CAN en una memoria USB o SD Card. Las dos PCBs constituyen el hardware del proyecto. El software se compone de dos programas. Un programa para la PCB del vehículo que emite los datos a la estación base, codificado en lenguaje C con ayuda del entorno de desarrollo MPLAB de Microchip. El otro programa hecho con LabView para la PCB de la estación base que recibe los datos provenientes del vehículo y los interpreta. Se propone un hardware y una capa o funciones de software para los microcontroladores PIC32 (similar al de otros proyectos del FSAE) para la transmisión de las tramas del bus CAN del vehículo de manera inalámbrica a una estación base, capaz de insertar tramas en el bus CAN del vehículo enviadas desde la estación base. También almacena estas tramas CAN en un dispositivo USB o SD Card situado en el vehículo. Para la transmisión de los datos se hizo un estudio de las frecuencias de transmisión, la legislación aplicable y los tipos de transceptores. Se optó por utilizar la banda de radiofrecuencia de uso común ISM de 433MHz mediante el transceptor integrado CC110L de Texas Instruments altamente configurable y con interfaz SPI. Se adquirieron dos parejas de módulos compatibles, con amplificador de potencia o sin él. LabView controla la estación que recoge las tramas CAN vía RF y está dotada del mismo transceptor de radio junto con un puente de comunicaciones SPI-USB, al que se puede acceder de dos diferentes maneras, mediante librerías dll, o mediante NI-VISA con transferencias RAW-USB. La aplicación desarrollada posee una interfaz configurable por el usuario para la muestra de los futuros sensores o actuadores que se incorporen en el vehículo y es capaz de interpretar las tramas CAN, mostrarlas, gráfica, numéricamente y almacenar esta información, como si fuera el cuadro de instrumentos del vehículo. Existe una limitación de la velocidad global del sistema en forma de cuello de botella que se crea debido a las limitaciones del transceptor CC110L por lo que si no se desea filtrar los datos que se crean necesarios, sería necesario aumentar el número de canales de radio para altas ocupaciones del bus CAN. Debido a la pérdida de relaciones con el INSIA, no se pudo probar de manera real en el propio vehículo, pero se hicieron pruebas satisfactorias (hasta 1,6 km) con una configuración de tramas CAN estándar a una velocidad de transmisión de 1 Mbit/s y un tiempo de bit de 1 microsegundo. El periférico CAN del PIC32 se programará para cumplir con estas especificaciones de la ECU del vehículo, que se presupone que es la MS3 Sport de Bosch, de la que LabView interpretará las tramas CAN recibidas de manera inalámbrica. Para poder probar el sistema, ha sido necesario reutilizar el hardware y adaptar el software del primer prototipo creado, que emite tramas CAN preprogramadas con una latencia también programable y que simulará al bus CAN proporcionando los datos a transmitir por el sistema que incorpora el vehículo. Durante el desarrollo de este proyecto, en las etapas finales, el fabricante del puente de comunicaciones SPI-USB MCP2210 liberó una librería (dll) compatible y sin errores, por lo que se nos ofrecía una oportunidad interesante para la comparación de las velocidades de acceso al transceptor de radio, que se presuponía y se comprobó más eficiente que la solución ya hecha mediante NI-VISA. ABSTRACT. The Formula SAE competition is an international university applied to technological innovation in vehicles racing type formula, in which each team, made up of students, should design, construct and test a prototype each year within certain rules. The challenge of FSAE is that it is an educational project farther away than a master class. The goal of the present project is to make a tool for other students to use it in his projects related to FSAE to test and improve the vehicle, and, the improvements that can be provided by the electronics could be materialized in a victory and win the competition with this competitive advantage. A telemetry system was developed. It sends the data provided by the car’s CAN bus through a radio frequency transceiver and receive commands to execute on the system, it provides by a base station on the ground. Moreover, constant verification in real time of the status of the car or data parameters like the revolutions per minute, pressure from collectors, water temperature, and so on, can be accessed from the base station on the ground, so that, it could be possible to study the behaviour of the vehicle in early phases of the car development. A printed circuit board, composed of two boards, and two software programs in two different languages, have been developed, and built for the project implementation. The software utilized to design the PCB is Orcad10.5/Layout. The base station PCB on a PC receives data from the PCB connected to the vehicle’s CAN bus and sends commands like set CAN filters or masks, activate data logger or inject CAN frames. This PCB is connected to a PC via USB and contains a bridge USB-SPI to communicate with a similar transceiver on the vehicle PCB. LabView controls this part of the system. A special virtual Instrument (VI) had been created in order to add future new elements to the vehicle, is a dashboard, which reads the data passed from the main VI and represents them graphically to studying the behaviour of the car on track. In this special VI other alums can make modifications to accommodate the data provided from the vehicle CAN’s bus to new elements on the vehicle, show or save the CAN frames in the form or format they want. Two methods to access to SPI bus of CC110l RF transceiver over LabView have been developed with minimum changes between them. Access through NI-VISA (Virtual Instrument Software Architecture) which is a standard for configuring, programming, USB interfaces or other devices in National Instruments LabView. And access through DLL (dynamic link library) supplied by the manufacturer of the bridge USB-SPI, Microchip. Then the work is done in two forms, but the dll solution developed shows better behaviour, and increase the speed of the system because has less overload of the USB bus due to a better efficiency of the dll solution versus VISA solution. The PCB connected to the vehicle’s CAN bus receives commands from the base station PCB on a PC, and, acts in function of the command or execute actions like to inject packets into CAN bus or activate data logger. Also sends over RF the CAN frames present on the bus, which can be filtered, to avoid unnecessary radio emissions or overflowing the RF transceiver. This PCB consists of two basic pieces: A microcontroller with 32 bit architecture PIC32MX795F512L from Microchip and the radio transceiver integrated circuit CC110l from Texas Instruments. The PIC32MX795F512L has an integrated CAN and several peripherals like SPI controllers that are utilized to communicate with RF transceiver and SD Card. The USB controller on the PIC32 is utilized to store CAN data on a USB memory, and change notification peripheral is utilized like an external interrupt. Hardware for other peripherals is accessible. The software part of this PCB is coded in C with MPLAB from Microchip, and programming over PICkit 3 Programmer, also from Microchip. Some of his libraries have been modified to work properly with this project and other was created specifically for this project. In the phase for RF selection and design is made a study to clarify the general aspects of regulations for the this project in order to understand it and select the proper band, frequency, and radio transceiver for the activities developed in the project. From the different options available it selects a common use band ICM, with less regulation and free to emit with restrictions and disadvantages like high occupation. The transceiver utilized to transmit and receive the data CC110l is an integrated circuit which needs fewer components from Texas Instruments and it can be accessed through SPI bus. Basically is a state machine which changes his state whit commands received over an SPI bus or internal events. The transceiver has several programmable general purpose Inputs and outputs. These GPIOs are connected to PIC32 change notification input to generate an interrupt or connected to GPIO to MCP2210 USB-SPI bridge to inform to the base station for a packet received. A two pair of modules of CC110l radio module kit from different output power has been purchased which includes an antenna. This is to keep away from fabrication mistakes in RF hardware part or designs, although reference design and gerbers files are available on the webpage of the chip manufacturer. A neck bottle is present on the complete system, because the maximum data rate of CC110l transceiver is a half than CAN bus data rate, hence for high occupation of CAN bus is recommendable to filter the data or add more radio channels, because the buffers can’t sustain this load along the time. Unfortunately, during the development of the project, the relations with the INSIA, who develops the vehicle, was lost, for this reason, will be made impossible to test the final phases of the project like integration on the car, final test of integration, place of the antenna, enclosure of the electronics, connectors selection, etc. To test or evaluate the system, it was necessary to simulate the CAN bus with a hardware to feed the system with entry data. An early hardware prototype was adapted his software to send programed CAN frames at a fixed data rate and certain timing who simulate several levels of occupation of the CAN Bus. This CAN frames emulates the Bosch ECU MS3 Sport.

Passenger Exposure to Magnetic Fields due to the Batteries of an Electric Vehicle

In electric vehicles, passengers sit very close to an electric system of significant power. The high currents achieved in these vehicles mean that the passengers could be exposed to significant magnetic fields. One of the electric devices present in the power train are the batteries. In this paper, a methodology to evaluate the magnetic field created by these batteries is presented. First, the magnetic field generated by a single battery is analyzed using finite elements simulations. Results are compared to laboratory measurements, taken from a real battery, in order to validate the model. After this, the magnetic field created by a complete battery pack is estimated and results are discussed.

Analysis and Design Considerations of an Electric Vehicle Powertrain regarding Energy Efficiency and Magnetic Field Exposure

En esta tesis se analiza el sistema de tracción de un vehículo eléctrico de batería desde el punto de vista de la eficiencia energética y de la exposición a campos magnéticos por parte de los pasajeros (radiación electromagnética). Este estudio incluye tanto el sistema de almacenamiento de energía como la máquina eléctrica, junto con la electrónica de potencia y los sistemas de control asociados a ambos. Los análisis y los resultados presentados en este texto están basados en modelos matemáticos, simulaciones por ordenador y ensayos experimentales a escala de laboratorio. La investigación llevada a cabo durante esta tesis tuvo siempre un marcado enfoque industrial, a pesar de estar desarrollada en un entorno de considerable carácter universitario. Las líneas de investigación acometidas tuvieron como destinatario final al diseñador y al fabricante del vehículo, a pesar de lo cual algunos de los resultados obtenidos son preliminares y/o excesivamente académicos para resultar de interés industrial. En el ámbito de la eficiencia energética, esta tesis estudia sistemas híbridos de almacenamiento de energía basados en una combinación de baterías de litio y supercondensadores. Este tipo de sistemas son analizados desde el punto de vista de la eficiencia mediante modelos matemáticos y simulaciones, cuantificando el impacto de ésta en otros parámetros tales como el envejecimiento de las baterías. Respecto a la máquina eléctrica, el estudio se ha centrado en máquinas síncronas de imanes permanentes. El análisis de la eficiencia considera tanto el diseño de la máquina como la estrategia de control, dejando parcialmente de lado el inversor y la técnica de modulación (que son incluidos en el estudio como fuentes adicionales de pérdidas, pero no como potenciales fuentes de optimización de la eficiencia). En este sentido, tanto la topología del inversor (trifásico, basado en IGBTs) como la técnica de modulación (control de corriente en banda de histéresis) se establecen desde el principio. El segundo aspecto estudiado en esta tesis es la exposición a campos magnéticos por parte de los pasajeros. Este tema se enfoca desde un punto de vista predictivo, y no desde un punto de vista de diagnóstico, puesto que se ha desarrollado una metodología para estimar el campo magnético generado por los dispositivos de potencia de un vehículo eléctrico. Esta metodología ha sido validada mediante ensayos de laboratorio. Otros aspectos importantes de esta contribución, además de la metodología en sí misma, son las consecuencias que se derivan de ella (por ejemplo, recomendaciones de diseño) y la comprensión del problema proporcionada por esta. Las principales contribuciones de esta tesis se listan a continuación: una recopilación de modelos de pérdidas correspondientes a la mayoría de dispositivos de potencia presentes en un vehículo eléctrico de batería, una metodología para analizar el funcionamiento de un sistema híbrido de almacenamiento de energía para aplicaciones de tracción, una explicación de cómo ponderar energéticamente los puntos de operación par-velocidad de un vehículo eléctrico (de utilidad para evaluar el rendimiento de una máquina eléctrica, por ejemplo), una propuesta de incluir un convertidor DC-DC en el sistema de tracción para minimizar las pérdidas globales del accionamiento (a pesar de las nuevas pérdidas introducidas por el propio DC-DC), una breve comparación entre dos tipos distintos de algoritmos de minimización de pérdidas para máquinas síncronas de imanes permanentes, una metodología predictiva para estimar la exposición a campos magnéticos por parte de los pasajeros de un vehículo eléctrico (debida a los equipos de potencia), y finalmente algunas conclusiones y recomendaciones de diseño respecto a dicha exposición a campos magnéticos. ABSTRACT This dissertation analyzes the powertrain of a battery electric vehicle, focusing on energy efficiency and passenger exposure to electromagnetic fields (electromagnetic radiation). This study comprises the energy storage system as well as the electric machine, along with their associated power electronics and control systems. The analysis and conclusions presented in this dissertation are based on mathematical models, computer simulations and laboratory scale tests. The research performed during this thesis was intended to be of industrial nature, despite being developed in a university. In this sense, the work described in this document was carried out thinking of both the designer and the manufacturer of the vehicle. However, some of the results obtained lack industrial readiness, and therefore they remain utterly academic. Regarding energy efficiency, hybrid energy storage systems consisting in lithium batteries, supercapacitors and up to two DC-DC power converters are considered. These kind of systems are analyzed by means of mathematical models and simulations from the energy efficiency point of view, quantifying its impact on other relevant aspects such as battery aging. Concerning the electric machine, permanent magnet synchronous machines are studied in this work. The energy efficiency analysis comprises the machine design and the control strategy, while the inverter and its modulation technique are taken into account but only as sources of further power losses, and not as potential sources for further efficiency optimization. In this sense, both the inverter topology (3-phase IGBT-based inverter) and the switching technique (hysteresis current control) are fixed from the beginning. The second aspect studied in this work is passenger exposure to magnetic fields. This topic is approached from the prediction point of view, rather than from the diagnosis point of view. In other words, a methodology to estimate the magnetic field generated by the power devices of an electric vehicle is proposed and analyzed in this dissertation. This methodology has been validated by laboratory tests. The most important aspects of this contribution, apart from the methodology itself, are the consequences (for instance, design guidelines) and the understanding of the magnetic radiation issue provided by it. The main contributions of this dissertation are listed next: a compilation of loss models for most of the power devices found in a battery electric vehicle powertrain, a simulation-based methodology to analyze hybrid energy storage performance in traction applications, an explanation of how to assign energy-based weights to different operating points in traction drives (useful when assessing electrical machine performance, for instance), a proposal to include one DC-DC converter in electric powertrains to minimize overall power losses in the system (despite the new losses added by the DC-DC), a brief comparison between two kinds of loss-minimization algorithms for permanent magnet synchronous machines in terms of adaptability and energy efficiency, a predictive methodology to estimate passenger magnetic field exposure due to power devices in an electric vehicle, and finally some useful conclusions and design guidelines concerning magnetic field exposure.

A Vision-based Quadrotor Multi-robot Solution for the Indoor Autonomy Challenge of the 2013 International Micro Air Vehicle Competition

This paper presents a completely autonomous solution to participate in the Indoor Challenge of the 2013 International Micro Air Vehicle Competition (IMAV 2013). Our proposal is a multi-robot system with no centralized coordination whose robotic agents share their position estimates. The capability of each agent to navigate avoiding collisions is a consequence of the resulting emergent behavior. Each agent consists of a ground station running an instance of the proposed architecture that communicates over WiFi with an AR Drone 2.0 quadrotor. Visual markers are employed to sense and map obstacles and to improve the pose estimation based on Inertial Measurement Unit (IMU) and ground optical flow data. Based on our architecture, each robotic agent can navigate avoiding obstacles and other members of the multi-robot system. The solution is demonstrated and the achieved navigation performance is evaluated by means of experimental flights. This work also analyzes the capabilities of the presented solution in simulated flights of the IMAV 2013 Indoor Challenge. The performance of the CVG UPM team was awarded with the First Prize in the Indoor Autonomy Challenge of the IMAV 2013 competition.