Dissertations / Theses on the topic 'Real-Time vehicle simulation'

Software simulation is vitally important in a number of industries. It allows engineers to test new products before they leave the drawing board and enables tests that would otherwise be difficult or impossible to perform. Traditional engineering simulations use sophisticated numerical methods to produce models that are highly accurate, but computationally expensive and time-consuming to use. This accuracy is essential in the latter stages of the design process, but can make the early stages - which often involve frequent, iterative design changes - a lengthy and frustrating process. Additionally, the scope of such simulations is often limited by their complexity. An attempt has been made to produce an alternative, real-time simulation tool, developed using software and development practices from the video games industry, which are designed to simulate and render virtual environments efficiently in real-time. In particular, this tool makes use of real-time physics engines; iterative, constraint-based solver systems that use rigid body dynamics to approximate the movements and interactions of physical entities. This has enabled the near-real-time simulation of multi-vehicle trains, and is capable of producing reasonably realistic results, within an acceptably small error bound, for situations in which a real-time simulation would be used as an alternative to existing methods. This thesis presents the design, development and evaluation of this simulation tool, which is based on NVidia's PhysX Engine. The aim was to determine the suitability of a physics engine-based tool for simulating various aspects of rail dynamics. This thesis intends to demonstrate that such a tool, if configured and augmented appropriately, can produce results that approach those produced by traditional methods and is capable of simulating aspects of rail dynamics that are otherwise prohibitively expensive or beyond the capabilities of existing solutions, and may therefore be a useful supplement to the existing tolls used in the rail industry.

In recent years, more and more light aircraft enter our daily life, from Agricultural applications, emergency rescue, flight experiment and training to Barriers to entry, light aircraft always have their own advantages. Thus, they have become more and more popular. However, in the process of GDP research about Flight Control System design for the Flying Crane, the author read a lot of literature about Flight Control System design, then noticed that the research in Flight Control System have apparently neglected to Low-cost vehicles. So it is necessary to do some study about Flight Control System for this kind of airplane. The study will more concern the control law design for ultra-light aircraft, the author hopes that with an ‘intelligence’ Flight Control System design, this kind of aircraft could sometimes perform flying tasks according to a prearranged flight path and without a pilot. As the Piper J-3 cub is very popular and the airframe data can be obtained more easily, it was selected as an objective aircraft for the control law design. Finally, a ¼ scale Piper J-3 cub model is selected and the aerodynamics coefficients are calculated by DATCOM and AVL. Based on the forces and moments acting on the aircraft, the trim equilibrium was calculated for getting proper dynamics coefficients for the selected flight conditions. With the aircraft aerodynamics coefficients, the aircraft dynamics characteristics and flying qualities are also analyzed. The model studied in this thesis cannot answer level one flying qualities in the longitudinal axis, which is required by MIL-F- 8785C. The stability augment system is designed to improve the flying qualities of the longitudinal axis. The work for autopilot design in this thesis includes five parts. First, the whole flight profile is designed to automatically control aircraft from takeoff to landing. Second, takeoff performance and guidance law is studied. Then, landing performance and trajectory is also investigated. After that, the control law design is decoupled into longitudinal axis and later-directional axis. Finally, simulation is executed to check the performance for the auto-controller.

La simulation de systèmes d'énergie est un outil important pour la conception, le développement et l'évaluation de nouvelles architectures et des contrôles grille dans le concept de réseau intelligent pour les dernières décennies. Cet outil a évolué pour répondre aux questions proposées par les chercheurs et les ingénieurs dans les applications de l'industrie, et pour offrant des différentes alternatives pour couvrir plusieurs scénarios réalistes.Aujourd'hui, en raison des progrès récents dans le matériel informatique, la Simulation numérique en temps réel (DRTS) est utilisée pour concevoir des systèmes de puissance, afin de soutenir les décisions prises dans les systèmes de gestion de l'énergie automatisés (SME) et de réduire le délai de commercialisation de produits, entre des autres applications.Les simulations de réseaux électriques peuvent être classées dans les catégories suivantes: (1) la simulation analogique (2) hors simulation de ligne (3) de simulation entièrement numérique (4) la simulation rapide (5) Contrôleur Hardware-In-the-Loop (CHIL) et (6) Puissance Hardware-In-the-Loop (PHIL).Les dernière 3 sont axés sur la simulation Real-Time hardware-in-the-Loop (HIL RT-). Ces catégories portent sur les questions liées à Transitoires électromagnétiques (liste EMT), la simulation de phaseurs ou mixte (phaseur et EMT). Comme mentionné ci-dessus, ces progrès sont possibles en raison de l'évolution des architectures informatiques (matériels et logiciels); Cependant, pour le cas particulier de l'analyse des flux de puissance des réseaux de distribution (DS), il y a encore des défis à résoudre.Les architectures informatiques actuelles sont composées de plusieurs noyaux, laissant derrière lui le paradigme de la programmation séquentielle et conduisant les développeurs de systèmes numériques pour examiner des concepts comme le parallélisme, la concurrence et les événements asynchrones. D'autre part, les méthodes pour résoudre le flux de puissance dynamique des systèmes de distribution considérer le système comme un seul bloc; ainsi, ils utilisent une seule base pour l'analyse des flux de puissance, indépendamment de l'existence de plusieurs cœurs disponibles pour améliorer les performances de la simulation.Répartis dans des procédés en phase et de la séquence, ces procédés ont en caractéristiques communes telles que l'examen d'une seule matrice creuse pour décrire les DS et qu'ils peuvent résoudre simultanément une seule fréquence.Ces caractéristiques font dès les méthodes mentionné sont pas appropriées pour le traitement avec multiple noyaux. En conséquence, les architectures informatiques actuelles sont sous-utilisés, et dégrade la performance des simulateurs lors de la manipulation de grandes DS échelle, changer DS topologie et y compris les modèles avancés, entre autres des activités de la vie réelle.Pour relever ces défis Cette thèse propose une approche appelée A-Diakoptics, qui combine la puissance de Diakoptics et le modèle de l'acteur; le but est de faire toute méthode classique d'analyse de flux d'énergie appropriée pour le traitement multithread. En conséquence, la nature et la complexité du système d'alimentation peuvent être modélisées sans affecter le temps de calcul, même si plusieurs parties du système d'alimentation fonctionnent à une fréquence de base différente comme dans le cas de micro-réseaux à courant continu. Par conséquent, l'analyse des flux de charge dynamique de DS peut être effectuée pour couvrir les besoins de simulation différents tels que la simulation hors ligne, simulation rapide, CHIL et PHIL. Cette méthode est une stratégie avancée pour simuler les systèmes de distribution à grande échelle dans des conditions déséquilibrées; couvrant les besoins de base pour la mise en œuvre d'applications de réseaux intelligents
Simulation of power systems is an important tool for designing, developing and assessment of new grid architectures and controls within the smart grid concept for the last decades. This tool has evolved for answering the questions proposed by academic researchers and engineers in industry applications; providing different alternatives for covering several realistic scenarios. Nowadays, due to the recent advances in computing hardware, Digital Real-Time Simulation (DRTS) is used to design power systems, to support decisions made in automated Energy Management Systems (EMS) and to reduce the Time to Market of products, among other applications.Power system simulations can be classified in the following categories: (1) Analog simulation (2) off line simulation (3) Fully digital simulation (4) Fast simulation (5) Controller Hardware-In-the-Loop (CHIL) simulation and (6) Power Hardware-In-the-Loop (PHIL) simulation. The latest 3 are focused on Real-Time Hardware-In-the-Loop (RT-HIL) simulation. These categories cover issues related to Electromagnetic Transients (EMT), phasor simulation or mixed (phasor and EMT). As mentioned above, these advances are possible due to the evolution of computing architectures (hardware and software); however, for the particular case of power flow analysis of Distribution Systems (DS) there are still challenges to be solved.The current computing architectures are composed by several cores, leaving behind the paradigm of the sequential programing and leading the digital system developers to consider concepts such as parallelism, concurrency and asynchronous events. On the other hand, the methods for solving the dynamic power flow of distribution systems consider the system as a single block; thus they only use a single core for power flow analysis, regardless of the existence of multiple cores available for improving the simulation performance.Divided into phase and sequence frame methods, these methods have in common features such as considering a single sparse matrix for describing the DS and that they can solve a single frequency simultaneously. These features make of the mentioned methods non-suitable for multithread processing. As a consequence, current computer architectures are sub-used, affecting simulator's performance when handling large scale DS, changing DS topology and including advanced models, among others real life activities.To address these challenges this thesis proposes an approach called A-Diakoptics, which combines the power of Diakoptics and the Actor model; the aim is to make any conventional power flow analysis method suitable for multithread processing. As a result, the nature and complexity of the power system can be modeled without affecting the computing time, even if several parts of the power system operate at different base frequency as in the case of DC microgrids. Therefore, the dynamic load flow analysis of DS can be performed for covering different simulation needs such as off-line simulation, fast simulation, CHIL and PHIL. This method is an advanced strategy for simulating large-scale distribution systems in unbalanced conditions; covering the basic needs for the implementation of smart grid applications

Les activités de recherche ont été menées en collaboration avec l'Université de Bologne, l'Université Paris-Est et l'Université Gustave Eiffel sous la forme d'un doctorat cotutelle. Les activités sont divisées en deux macro-domaines ; les études de simulation de conduite réalisées à l'Université Gustave Eifel (IFSTTAR) et les expériences sur route organisées par l'Université de Bologne. La première partie de la recherche se concentre sur l'amélioration de la fidélité physique du simulateur de conduite à deux degrés de liberté avec une attention particulière aux signaux de mouvement et au modèle de dynamique du véhicule. Ce dernier a été développé dans MATLAB-Simulink et a la capacité de calculer en temps réel les états du véhicule et de contrôler la plateforme de mouvement. Au cours de cette phase de la recherche, des algorithmes de repères de mouvement ont été développés pour contrôler les mouvements du simulateur et l'effet des signaux de mouvement sur le comportement des conducteurs a été analysé par expérimentation. Les résultats de ces études sont discutés dans les cas d’études I et II. Dans la deuxième partie de la recherche, les performances du conducteur et le comportement visuel ont été étudiés sur la route sous différents scénarios. Le comportement visuel du conducteur a été enregistré à l'aide d'un dispositif de suivi oculaire monté sur la tête, tandis que la trajectoire du véhicule a été enregistrée avec un véhicule instrumenté équipé du système de positionnement mondial. Au cours de cette phase, plusieurs études de cas ont été développées pour surveiller le comportement des conducteurs en milieu naturaliste. La cas d'étude III vise à intégrer l'audit de sécurité routière traditionnel à un système innovant de surveillance du comportement des conducteurs. L’expérimentation sur route avec des conducteurs a été réalisée sur une artère urbaine afin d'évaluer l'approche proposée à travers des techniques innovantes de suivi des conducteurs. Ces mêmes instruments de surveillance de la conduite ont été utilisés pour évaluer l'amélioration d'un passage pour piétons au rond-point dans le cas d'étude IV. Les données de suivi oculaire ont été évaluées dans les deux études afin d'identifier un indicateur d'attention visuelle du conducteur en fonction de la position et de la durée du regard des participants. Une attention particulière est accordée à la sécurité des conducteurs vulnérables dans les zones urbaines lors de l'étude du comportement de conduite naturaliste. Le cas d'étude V a analysé le comportement de conduite du conducteur en phase d'approche d'un passage prioritaire à vélo à l'aide de mesures de sécurité de substitution. Les mesures de performance des conducteurs telles que le temps de réaction de la perception et le comportement du regard ont été utilisées pour évaluer le niveau de sécurité du passage à niveau, équipé de systèmes de signalisation standard et innovants. L’amélioration du comportement cédant du conducteur vers un passage à niveau non signalé pendant la nuit et sa réaction à un système d’alarme d’éclairage intégré ont été évaluées dans le cas d’étude VI. La dernière phase de la thèse est consacrée à l'étude du régulateur de vitesse adaptatif (ACC) avec expérimentation sur route et sur simulateur. L'expérimentation sur route a étudié l'influence du système d'aide à la conduite sur l'adaptation des conducteurs avec une évaluation objective et subjective, dans laquelle un instrument de suivi oculaire et un casque EEG ont été utilisés pour surveiller les conducteurs sur une autoroute. Les résultats sont présentés dans les cas d’études VII et VIII et l’attention visuelle des conducteurs a été réduite en raison de l’adaptation à l’ACC dans le scénario de suivi de véhicule. Les résultats de l'essai sur route ont ensuite été utilisés pour reproduire le même scénario dans le simulateur de conduite et l'adaptation du comportement des conducteurs avec l'utilisation de l'ACC a été confirmée par l'expérimentation
The related research activities were carried out in collaboration with the University of Bologna, Paris-Est University and Gustave Eiffel University (IFSTTAR) in the form of a cotutelle PhD. The activities are divided into two macro areas ; the driving simulation studies conducted in Gustave Eifel University (IFSTTAR) and on-road experiments organized by the University of Bologna. The first part of the research is focused on improving the physical fidelity of the two DOF driving simulator with particular attention to motion cueing and vehicle dynamics model. The vehicle dynamics model has been developed in MATLAB-Simulink and has the ability of real-time calculation of the vehicle states and control the motion platform. During this phase of the research, motion cueing algorithms were developed to control the simulator movements and the effect of the motion cues on drivers’ behaviour was analysed through experimentation. The results of these studies are discussed in the case studies I and II. In the second part of the research, the driver performance and visual behaviour were studied on the road under different scenarios. The driver visual behaviour was recorded with the use of a head mounted eye-tracking device, while the vehicle trajectory was registered with an instrumented vehicle equipped with Global Positioning System (GPS). During this phase, several case studies were developed to monitor drivers’ behaviour in the naturalistic environment. Case study III aims to integrate the traditional road safety auditing with an innovative driver behaviour monitoring system. The real road experiment with drivers was carried out in an urban arterial road in order to evaluate the proposed approach through innovative driver monitoring techniques. These same driving monitoring instruments were used for evaluating the improvement of a pedestrian crossing at the roundabout in case study IV. The eye-tracking data were evaluated in both studies in order to identify a driver visual attention indicator based on the participants gaze position and duration. Significant attention is given to the safety of vulnerable drivers in urban areas during the naturalistic driving behaviour study. Case study V analyzed the driver yielding behaviour in approach phase to a bicycle priority crossing with the use of surrogate safety measures. The drivers’ performance measures such as perception reaction time and gaze behaviour were used to assess the safety level of the crossing equipped with standard and innovative signalling systems. The improvement on the driver’s yielding behaviour towards an un-signalized crossing during night-time and their reaction to an integrated lighting-warning system was evaluated in the case study VI. The last phase of the thesis is dedicated to the study of Adaptive Cruise Control (ACC) with on-road and simulator experimentation. The on-road experimentation investigated the driver assistant system influence on the drivers' adaptation with objective and subjective assessment, in which an eye tracking instrument and EEG helmet were used to monitor the drivers on a highway. The results are presented in Case studies VII and VIII and drivers’s visual attention was reduced due to adaptation to the ACC in the car following scenario. The results of the on-road test were later used to reproduce to the same scenario in the driving simulator and the adaptation of drivers’ behaviour with the use of ACC was confirmed through experimentation

After undergoing a study about current engine modelling and mapping approaches as well as the engine modelling requirements for different applications, a major problem found to be present is the extensive and time consuming mapping procedure that every engine has to go through so that all control parameters can be derived from experimental data. To improve this, a cycle-by-cycle modelling approach has been chosen to mathematically represent reciprocating engines starting by a complete dynamics crankshaft mechanism model which forms the base of the complete engine model. This system is modelled taking into account the possibility of a piston pin offset on the mechanism. The derived Valvetrain model is capable of representing a variable valve lift and phasing Valvetrain which can be used while modelling most modern engines. A butterfly type throttle area model is derived as well as its rate of change which is believed to be a key variable for transient engine control. In addition, an approximation throttle model is formulated aiming at real-time applications. Furthermore, the engine inertia is presented as a mathematical model able to be used for any engine. A spark ignition engine simulation (SIES) framework was developed in MATLAB SIMULINK to form the base of a complete high fidelity cycle-by-cycle simulation model with its major target to provide an environment for virtual engine mapping procedures. Some experimental measurements from an actual engine are still required to parameterise the model, which is the reason an engine mapping (EngMap) framework has been developed in LabVIEW, It is shown that all the moving engine components can be represented by a single cyclic variable which can be used for flow model development.

Veículos Submarinos Não Tripulados (UUVs Unmanned Underwater Vehicles) possuem muitas aplicações comerciais, militares e científicas devido ao seu elevado potencial e relação custo-desempenho considerável quando comparados a meios tradicionais utilizados para a obtenção de informações provenientes do meio subaquático. O desenvolvimento de uma plataforma de testes e amostragem confiável para estes veículos requer o projeto de um sistema completo além de exigir diversos e custosos experimentos realizados no mar para que as especificações possam ser devidamente validadas. Modelagem e simulação apresentam medidas de custo efetivo para o desenvolvimento de componentes preliminares do sistema (software e hardware), além de verificação e testes relacionados à execução de missões realizadas por veículos submarinos reduzindo, portanto, a ocorrência de potenciais falhas. Um ambiente de simulação preciso pode auxiliar engenheiros a encontrar erros ocultos contidos no software embarcado do UUV além de favorecer uma maior introspecção dentro da dinâmica e operação do veículo. Este trabalho descreve a implementação do algoritmo de controle de um UUV em ambiente MATLAB/SIMULINK, sua conversão automática para código compilável (em C++) e a verificação de seu funcionamento diretamente no computador embarcado por meio de simulações. Detalham-se os procedimentos necessários para permitir a conversão dos modelos em MATLAB para código C++, integração do software de controle com o sistema operacional de tempo real empregado no computador embarcado (VxWORKS) e a estratégia de simulação com Hardware In The Loop (HIL) desenvolvida - A principal contribuição deste trabalho é apresentar de forma racional uma estrutura de trabalho que facilite a implementação final do software de controle no computador embarcado a partir do modelo desenvolvido em um ambiente amigável para o projetista, como o SIMULINK.
Unmanned Underwater Vehicles (UUVs) have many commercial, military, and scientific applications because of their potential capabilities and significant costperformance improvements over traditional means of obtaining valuable underwater information The development of a reliable sampling and testing platform for these vehicles requires a thorough system design and many costly at-sea trials during which systems specifications can be validated. Modeling and simulation provide a cost-effective measure to carry out preliminary component, system (hardware and software), and mission testing and verification, thereby reducing the number of potential failures in at-sea trials. An accurate simulation environment can help engineers to find hidden errors in the UUV embedded software and gain insights into the UUV operation and dynamics. This work describes the implementation of a UUV\'s control algorithm using MATLAB/SIMULINK, its automatic conversion to an executable code (in C++) and the verification of its performance directly into the embedded computer using simulations. It is detailed the necessary procedure to allow the conversion of the models from MATLAB to C++ code, integration of the control software with the real time operating system used on the embedded computer (VxWORKS) and the developed strategy of Hardware in the loop Simulation (HILS). The Main contribution of this work is to present a rational framework to support the final implementation of the control software on the embedded computer, starting from the model developed on an environment friendly to the control engineers, like SIMULINK.

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The NPS Autonomous Underwater Vehicle Simulator is a joint project between the Naval Postgraduate School's Mechanical Engineering and Computer Science Departments. In order to test mission planning and execution software, an accurate vehicle dynamic model is required. Using dynamics based upon the Navy's Swimmer Delivery Vehicle (SDV), there is a need to continually update the hydrodynamic coefficients based upon actual vehicle-in-water testing. The NPS AUV Dynamic Simulator contains a full set of submarine equations of motion and hydrodynamic coefficients. The coefficients are modifiable on-line, and a replay capability exists for further performance review. Using Monterey Bay as an underwater testing environment, there is need to be able to display expansive terrain data while maintaining the real time simulation. The Variable Terrain Resolution Algorithm incorporated into the NPS AUV Dynamic Simulator enables the entire Monterey Bay data base to be displayed in real time. Resolution adjustments are made automatically based upon the vehicle's depth level and system performance.

This master thesis is a part of a research project where Luleå University of Technology (LTU) collaborates with University of Oulu, SINTEF Narvik and Oulu University of Applied Sciences. The goal with the research project is to develop a Nordic platform for development of autonomous, environmental friendly and energy efficient heavy vehicles in the forest, harbor and mining industry. The purpose with the master thesis is to assist LTU in their role in the research project. The Nordic platform was positioned in the product development process, with the result that it could be useful in the fourth phase ”Detail design” and in the fifth phase ”Testing and refinement” in the Ulrich and Eppinger product development process. A methodology has been developed, covering all necessary steps going from an assembly of a vehicle in an arbitrary CAD program to perform real time simulations (including HiL simulations) of the vehicle in Simulink. The off-road research platform for forest- and agriculture applications developed by LTU was used as a case study in the master thesis. Applying the methodology on this platform showed that choosing correct simulation frequency is important and that graphics enabled in real time simulations requires large computational power.

With the continuous progress on autonomous vehicle and remote drivingtechniques, connection quality demands are changing compared withconventional quality of service. Vehicle to everything communication, asthe connectivity basis for these applications, has been built up on LongTerm Evolution basis, but due to various ethical and environmental issues,few implementations have been made in reality. Therefore simulation approachesare believed to provide valuable insights.To fully model an LTE vehicular network, in this work we first providea comparison study to select the preferable LTE simulator. Aimingto integrate communication nodes with mobility, a solution for simulationframework is developed based on a state-of-art comparison study on theexisting simulator frameworks. We then further develop the network simulator,and complement it with hybrid wireless channel modeling, channeland quality of service aware scheduler, and admission control strategies. Interms of instant optimization of the network, real-time access is emulatedfor external devices to communicate with the simulator. In this thesis,the evaluation of the framework performance considers two aspects: theperformance of the simulator in LTE V2X use case and the feasibility ofthe service, specifically, remote driving, under realistic network capacity.For our framework, the results indicate that it is feasible to realize remotedriving in an LTE urban scenario, but, as an example, we show that foran area of Kista, five vehicles could be hold by a base-station with guaranteedservice at most.
Med kontinuerliga framstegen p°a autonomt fordon och fj¨arrkontrollteknikf¨or¨andras kravet p°a anslutningskvalitet i j¨amf¨orelse med konventionell servicekvalitet.Fordon till allting (V2X) kommunikation, som anslutningsgrundf¨or dessa applikationer, har byggts upp p°a basis av Long TermEvolution (LTE) system, men p°a grund av olika etiska och milj¨om¨assigaproblem har f°a implementeringar gjorts i verkligheten. D¨arf¨or antas simuleringsmetoderge v¨ardefulla insikter.Att fullt ut modellera ett LTE-fordon n¨atverk, i det h¨ar arbetet ger vif¨orst en j¨amf¨orelsestudie f¨or att v¨alja den f¨oredragna LTE-simulatorn.I syfte att integrera kommunikationsnoder med r¨orlighet utvecklas enl¨osning f¨or ett simuleringsramverk baserat p°a en j¨amf¨orelsestudie p°a befintligasimulatorramar. Vi utvecklar sedan n¨atverkssimulatorn ytterligare,och kompletterar den med hybrid tr°adl¨os kanalmodellering, kanal ochservicekvalitetmedvetna schemal¨aggning och antagningskontrollstrategier.N¨ar det g¨aller direkt n¨atverksoptimering, emuleras realtidsanslutningav externa enheter f¨or att kommunicera med simulatorn. I denna avhandlingutv¨arderas ramverken i tv°a aspekter: simulatorns prestanda i LTEV2X-anv¨andningsomr°adet och genomf¨orbarheten av tj¨ansten, s¨arskilt fj¨arrk¨orning,under realistisk n¨atkapacitet. In v°ara ramverk visar resultaten att det ¨arm¨ojligt att realisera fj¨arrk¨orning i ett LTE-urbana scenario, men som exempelvisar vi att f¨or ett omr°ade i Kista skulle som mest fem fordon kunnask¨otas av en basstation med garanterad service.

Cette thèse traite de modélisation des systèmes complexes. Dans ce cadre, l'approche est basée sur les Modèles Structurés en Second Ordre (MSSO). Afin d'utiliser cette classe de modèles, les propriétés telles que l'atteignabilité, l'observabilité et les grammiens, bien connues pour les réalisations d'états, sont étendues aux MSSO.Lors de la co-simulation d'un système, des éléments de natures différentes (physiques et logicielles) sont intégrés et la simulation est effectuée en temps réel. Or, les modèles d'ordre élevés sont couteux en temps de calcul, ce qui rend difficile ce type de simulation. Ainsi, des méthodes de réduction de modèle sont explorées. En particulier, de nouvelles méthodes, permettant de préserver la structure des modèles avec une bonne erreur d'approximation sont présentées.Ces développements sont appliqués à la co-simulation de modèles véhicules sous forme de MSSO. Le modèle créé est un modèle par blocs, complexe et non-linéaire. Afin d'appliquer les méthodes de réduction de modèle il est nécessaire de le linéariser. La structure par blocs permet de linéariser l'ensemble du modèle ou de ne linéariser que certaines sous parties du modèle.Ensuite, l'identification des paramètres est effectuée pour chaque sous-systèmes du véhicule. Une méthode d'interconnexion est ensuite proposée pour créer une représentation monobloc du modèle afin de réduire ce dernier. Au final, des essais en co-simulation de la partie arrière du véhicule sous forme de modèle interconnectée avec la partie avant du véhicule physiquement présente sur un banc de test, valide notre approche pour effectuer de la co-simulation temps réel avec matériel.x

The great potential benefits associated with SFF (satellite formation flying) have led to considerable research in this concept around the world. As it is a new field of research and the implementation of formation flying in practice brings some inherent challenges and risks It is therefore particularly useful to develop a real time platform, where formation flying theories, technologies, algorithms and their coordination in open and close loop can be tested in scenarios close to those actually expected. In this research a low cost, real time hardware in the loop (RTHIL) test bed for low earth orbit autonomous SFF consisting of nano satellites has been developed which can integrate original hardware in the close or open loop. The proposed real time close loop test bed consists of a real time SFF model, a real time relative navigation system, guidance and control algorithm, and GPS simulator. Different SFF models already developed by researchers have been studied for their potential use in a real time test bed. Due to the limitations associated with them a novel real time SFF model and algorithm has been developed for real time hardware in the loop test bed. This real time SFF model was downloaded to a setup of two single board real time computers connected to each other through a serial port. The hardware of the relative navigation system has been designed and developed in this research. Single frequency GPS has been used as the relative navigation sensor. A model has been developed to estimate the dynamic characteristics of the GPS receiver for LEO orbits. This model simulates the relative dynamics of the GPS constellation and the LEO satellite. S3C2410 has been selected as the navigation processor. Radio transceivers are used to exchange data between the satellites. A uC/OS-II real time operating system is used in the navigation software code. The Hardware and software structure has been developed to simulate both centralized and decentralized approaches. A novel relative navigation algorithm is discussed. A Graphical Interface Software (GIS) has also been developed to initialize hardware and software prior any simulation and test run. It synchronizes the start of simulation on all real time computers, relative navigation systems and other components/simulator. It captures real time data from the deputy satellite. It also provides different debug and test options. Offline simulations were run for three models Hill’s, COEPOKE and RTSFF models by considering gravitational and atmospheric perturbation. The comparison of the results showed that the RTSFF model is able to simulate formations both in circular and elliptical orbits satisfactorily. The analysis of these models on the basis of their mathematical derivations showed that the RTSFF model gives better results than other models. The worth of this model for the real time test bed has been shown by running real time simulations onto a network of two synchronized single board real time computers and when the results were compared with offline simulation results they were found to be quite satisfactory. The hardware of the relative navigation system has been checked and tested. A basic infrastructure for navigation software has been developed. Different open loop tests have been run to verify the working of the hardware and software and these have verified the correct functioning of the system. The navigation algorithm could not be implemented in the embedded environment, Due to the unavailability of GPS simulator, no close loop simulation or test has been performed. The functionality of all the software, models, hardware and their operational control under GIS software has been checked in real time environment and found to be working correctly and are ready to be run in any open loop or closed loop simulation test.

In recent years there has been a growth in the automotive industry, coupled with a growth in the amount of electronic components and systems in a modern vehicle. The higher amount of electronics has led to an increased amount of Electronic Control Units (ECU) in a vehicle which require advanced simulation based testing procedures throughout their development process. One such method is Hardware in the Loop (HIL) simulation in which a real ECU is connected to simulation models of its environment via a real-time simulator. This project is concerned with developing a plant model of a windscreen wiper system for use in the development of Jaguar Land Rover’s (JLR) body electronics ECU. The system is divided into four parts which are modelled separately: Wiper motor, linkages, arm and blades, and the windscreen environment. The wiper motor and mechanical elements models are derived and implemented using the physical modelling tools SimScape and SimMechanics. A dynamic friction model describing the interaction between the wiper blades and the windscreen is developed, based on results presented in the literature. A simple aerodynamic model describing the forces on the wiper blades is also established. The parameters of the models are derived using three sequential optimisation methods: Transfer function parameter identification, Genetic Algorithms (GA) and a nonlinear least squares local optimiser. A transfer function relating the motor current to the voltage was derived for step one, and a bespoke GA has been developed for step two. The parameters were successfully identified. Following this, Artificial Neural Networks (ANN) were used to convert the physical models into real-time capable models suitable for HIL simulation. Finally, adaptive control systems are designed in order to maintain the motor at a constant velocity. The models are presented in a Simulink library and graphical user interface modelling tool for ease of use.

Dans le cadre de la réalisation d'un capteur 3D pour l'assistance à la conduite automobile, nous avons élaboré un algorithme original permettant de construire des cartes de vitesse axiale pour une scène réelle. Le principe de notre méthode repose sur un traitement réalisé à partir d'une séquence de cartes de disparité établies à l'aide de couples d'images stéréoscopiques. Le traitement se décompose en deux phases. Dans la première phase, nous effectuons un traitement au niveau du point image fondé sur l'utilisation d'un ensemble détecteur-estimateur. Pour caractériser la vitesse axiale observée au niveau d'un pixel, nous définissons une modélisation 3D adaptée à la configuration du système utilisé. Dans la deuxième phase, nous faisons intervenir le voisinage du point image par l'utilisation d'opérations morphologiques. Cette approche évite l'utilisation d'une segmentation région et le problème de la reconnaissance d'objets. L'avantage de cette méthode réside dans le temps de calcul constant, en particulier indépendant du nombre d'objets contenus dans la scène. L'efficacité de la méthode présentée est illustrée par différents résultats obtenus à partir de séquences d'images de synthèse bruitées, puis de séquences d'images issues de scènes réelles.

Off-highway vehicle, such as excavators and forklifts, are heavy machines that are capable of causing harm to humans or damage property. Therefore, it is necessary to be able to develop interfaces for these kind of vehicles that can aid the operator to maintain a high level of situational awareness. How the interface affects the operators’ situational awareness is consequently an important metric to measure when evaluating the interface. Mixed reality simulators can be used to both develop and evaluate such interfaces in an immersive and safe environment. In this thesis we investigated how to measure situational awareness in a mixed-reality off-highway vehicle simulation scenario, without having to pause the scenario, by cross-referencing logs from the virtual environment and logs from the users' gaze position. Our method for investigating this research question was to perform a literature study and a user test. Each participant in the user test filled out a SART post-simulation questionnaire which we then compared with our measurement system.

The automotive safety company Veoneer are producers of high end driver visual assistance systems, but the knowledge about the absolute accuracy of their dynamic calibration algorithms that estimate the vehicle’s orientation is limited. In this thesis, a novel measurement system is proposed to be used in gathering reference data of a vehicle’s orientation as it is in motion, more specifically the pitch and roll angle of the vehicle. Focus has been to estimate how the uncertainty of the measurement system is affected by errors introduced during its construction, and to evaluate its potential in being a viable tool in gathering reference data for algorithm performance evaluation. The system consisted of three laser distance sensors mounted on the body of the vehicle, and a range of data acquisition sequences with different perturbations were performed by driving along a stretch of road in Linköping with weights loaded in the vehicle. The reference data were compared to camera system data where the bias of the calculated angles were estimated, along with the dynamic behaviour of the camera system algorithms. The experimental results showed that the accuracy of the system exceeded 0.1 degrees for both pitch and roll, but no conclusions about the bias of the algorithms could be drawn as there were systematic errors present in the measurements.
Bilsäkerhetsföretaget Veoneer är utvecklare av avancerade kamerasystem inom förarassistans, men kunskapen om den absoluta noggrannheten i deras dynamiska kalibreringsalgoritmer som skattar fordonets orientering är begränsad. I denna avhandling utvecklas och testas ett nytt mätsystem för att samla in referensdata av ett fordons orientering när det är i rörelse, mer specifikt dess pitchvinkel och rollvinkel. Fokus har legat på att skatta hur osäkerheten i mätsystemet påverkas av fel som introducerats vid dess konstruktion, samt att utreda dess potential när det kommer till att vara ett gångbart alternativ för att samla in referensdata för evaluering av prestandan hos algoritmerna. Systemet bestod av tre laseravståndssensorer monterade på fordonets kaross. En rad mätförsök utfördes med olika störningar introducerade genom att köra längs en vägsträcka i Linköping med vikter lastade i fordonet. Det insamlade referensdatat jämfördes med data från kamerasystemet där bias hos de framräknade vinklarna skattades, samt att de dynamiska egenskaperna kamerasystemets algoritmer utvärderades. Resultaten från mätförsöken visade på att noggrannheten i mätsystemet översteg 0.1 grader för både pitchvinklarna och rollvinklarna, men några slutsatser kring eventuell bias hos algoritmerna kunde ej dras då systematiska fel uppstått i mätresultaten.

Les travaux de recherche de la thèse de Rami Troudi répondent à trois problématiques :-la première est de concevoir un onduleur triphasé multiniveau pour des applications à base d’énergies renouvelables connectées au réseau de distribution, ou pour la motorisation des véhicules électriques. Dans la première application, l’utilisation de bras multiniveau limite fortement les inductances de couplage avec le réseau tandis que dans la deuxième application, le couple délivré par le moteur est de meilleure qualité.-la deuxième consiste à concevoir une structure de convertisseur DC-DC permettant de n’avoir qu’une seule source continue pour alimenter cet onduleur multiniveau. -la troisième est la conception d’une architecture de commande temps réel à base de microcontrôleurs permettant d’avoir une grande capacité d’évolution et de calcul et une facilité d’industrialisation.Le manuscrit de la thèse est organisé en quatre chapitres. Le premier chapitre présente un état de l’art des structures d’onduleur multiniveau. Cette technologie est devenue aujourd’hui un thème de recherche important. Ce chapitre donne les avantages et les inconvénients de chaque topologie d’onduleur multiniveau conventionnel ainsi que les nouvelles topologies permettant une réduction du nombre de composants. Ce chapitre fait aussi un état de l’art des structures de hacheurs avec une ou plusieurs entrées-sorties (MISO, MIMO et SIMO). Ce chapitre présente aussi les avantages et les inconvénients de chaque famille de structure avec leur commande. La fin du chapitre présente les nouvelles topologies retenues pour l’onduleur multiniveau et le hacheur SIQO (une entrée-quatre sorties).Le deuxième chapitre est consacré à la présentation de la structure de l’onduleur multiniveau proposé, ainsi qu’à l’étude de son mode de fonctionnement, de sa commande rapprochée et de son utilisation dans une application en boucle fermée. Ce chapitre montre que cette structure a l’avantage de minimiser les pertes dans les composants de puissance en ayant, à chaque instant, peu de composants qui conduisent le courant de chaque bras, ce qui permet d’augmenter son rendement. En plus, ce chapitre montre la simplicité de la commande rapprochée de l’onduleur en utilisant un algorithme très simple. Des essais expérimentaux sont donnés à la fin du chapitre après le descriptif de la maquette d’essai.Le troisième chapitre traite en détail la structure du convertisseur DC-DC SIQO utilisé pour alimenter l’onduleur multiniveau, son mode de fonctionnement, sa modélisation et le développement d’une commande multi-entrée multi-sortie (MIMO). Cette structure est conçue à partir d’un couplage de la structure SEPIC avec la structure à accumulation magnétique et du dédoublement de chaque sortie par un système d’aiguillage qui permet ainsi d’obtenir quatre sorties à partir d’une seule entrée DC. Chaque structure (SEPIC et à accumulation) gère deux sorties avec le calcul de deux rapports cycliques. Pour cela, une synthèse d’asservissement basée sur une méthode H_∞ est présentée pour être robuste aux variations des courants et aux changements de consigne. Les résultats des essais expérimentaux sont donnés à la fin du chapitre après le descriptif de la maquette d’essai.Le chapitre quatre aborde le développement de l’architecture de commande à base de microcontrôleurs. Cette structure est appliquée au contrôle de l’onduleur triphasé. Ce chapitre décrit toutes les fonctions qui composent cette architecture au niveau matériel et logiciel. Le fait de répartir les besoins matériels et algorithmiques sur plusieurs microcontrôleurs permet de faciliter l’évolution des demandes de fonctions supplémentaires à savoir le diagnostic et la reconfiguration d’un bras, ainsi que l’ajout de la fonction de filtrage actif. Cette architecture repose sur une communication par bus SPI (Serial Peripheral Interface) qui permet des échanges rapides entre les microcontrôleurs et aussi vers un système IHM (Interface Homme Machine)
Rami Troudi's thesis research work addresses three problematics:- the first is to design a three-phase multilevel inverter for applications based on renewable energies connected to the power grid, or for electric motor drive of electric vehicles. In the first application, the use of multilevel arms greatly limit the coupling inductances with the power grid, while in the second application, the torque delivered by the motor is of better quality.- the second is to design a DC-DC converter structure having only one DC source destinated to supply this multilevel inverter.- the third is the design of a real-time control architecture based on microcontrollers leading to a large capacity of evolution and calculation and an ease industrialization.The thesis manuscript is organized into four chapters.The first chapter presents a state of art of multilevel inverter structures. This technology is becoming an important research topic today. This chapter gives the advantages and disadvantages of each conventional multilevel inverter topology as well as the new topologies with a reduction in the number of components. This chapter also give a reviews of the state of art of chopper structures with one or multiple inputs-outputs (MISO, MIMO and SIMO). This chapter also presents the advantages and the disadvantages of each family of structure with their regulation. The end of the chapter presents the new topologies retained for the multilevel inverter and the SIQO chopper (one input-four outputs).The second chapter is devoted to the presentation of the structure of the proposed multilevel inverter, as well as to the study of its mode of operation, its close control device and its use in a closed loop application. This chapter shows that this structure has the advantage of minimizing losses in power components by having, at any time, few components that conduct the current of each arm, which allows to increase its efficiency. In addition, this chapter shows the simplicity of the used close control of the inverter employing a very simple algorithm. Experimental tests are given at the end of the chapter after the description of the test bed.The third chapter discusses in detail the structure of the SIQO DC-DC converter used to supply the multilevel inverter, its operation mode, its modeling and the development of a multi-input multi-output (MIMO) control. This structure is designed from a coupling of the SEPIC structure with the buck-boost structure and the doubling of each output by a switching system which leads to obtain four outputs from a single DC input. Each structure (SEPIC and buck-boost) manages two outputs with the calculation of two duty cycles. For this, a control synthesis based on an Hinfini method is presented to be robust to the variations of the currents and the changes of the setpoint. The results of the experimental tests are given at the end of the chapter after the description of the test bed.Chapter four discusses the development of one architecture based on multi-microcontroller system. This structure is applied to the control of the three-phase multilevel inverter. This chapter describes all the functions that compose this architecture at the hardware and software level. The distribution of the hardware and algorithmic needs several microcontrollers makes it easier to evolve the demands for additional functions, namely the diagnosis and reconfiguration of an arm, as well as the addition of the active filtering function. This architecture is based on SPI (Serial Peripheral Interface) bus communication which allows rapid exchanges between the microcontrollers and also towards an HMI (human-machine interfaces) system

碩士
大葉大學
機電自動化研究所碩士班
94
The study is going to research the ten degrees of freedom mathematic model of vehicle dynamic. It includes three different direction of vehicle movement and three Euler angle. Furthermore, it also includes the suspention of four wheels. The formula for automobile movement is ten degrees of freedom which purpose is to investigate the longitudinal and lateral forces and the yaw rate of vehicle. In addition, the automobile’s stableness is also examined while a controller is assembled afterward. As stimulating, the steering wheel was quickly turning around while vehicle without controller but in low friction on the ground. This factor of low friction conducts the longitudinal and lateral forces of tyres decreasing. Therefore, it cannot maintain the steady of vehicle and make vehicle tend to be slipping. However, after assembling vehicle with controller, the situation has been controlled. The controller would control one of the front wheels in order to increase or decrease the yaw rate. Throughout the stimulation, we understand the relationship between steering wheel and yaw rate. Moreover, after examining the angular magnitude of steering wheel we also obtained the variation between them. We applied these two message and their variation, the controller of vehicle steady was been designed. Plus, the stimulation of vehicle’s movement as well as the result were achieved.

碩士
國立成功大學
交通管理學系碩博士班
98
Intelligent Transportation Systems (ITS) focus on increasing the efficiency of existing surface transportation systems through the use of advanced computers, electronics, and communication technologies. Two types of communications are important in ITS, namely Vehicle-Infrastructure Integration (VII) and Inter-Vehicle Communication (IVC). VII focuses on the communication between vehicles and infrastructures and IVC focuses on the communication between vehicles and vehicles. The wireless communication network for vehicles in traffic networks based on VII and IVC is named Vehicular Ad-Hoc Network (VANET). This research proposes an integrated simulation framework for simulating VANET. The integrated framework establishes a feedback interface between two simulation components, traffic simulation and communication simulation. The traffic simulation is performed through DynaTAIWAN, a mesocopic simulation-assignment model, and the communication is simulated through Network Simulation version 2 (NS2). This framework is constructed to study the traffic impact of VANET. Within the framework, the information from network simulation is feedback to traffic simulation. When the traffic simulator receives the information from network simulator, the IVC vehicles can change route based on received information. Offline and online experiments are conducted to illustrate the proposed framework and possible benefits from VANET. The offline experiments are conducted to study possible impact of density and speed of vehicular flows and communication range. The results show that packet delivery rate decreases with respect to traffic density. The on-line experiments focus on the impact of information feedback interval on the performance of VANET. The results from the online experiments show that information feedback interval should be designed carefully in apply VANET in a traffic network.

碩士
國立中興大學
機械工程學系
91
The purpose of this thesis is to achieve the real-time dynamic simulation of High Mobility Multipurpose Wheel Vehicle (HMMWV) by using recursive dynamic equation and Baumgarte numerical integration stabilization method. Recursive dynamic equation uses relative coordinates as generalized coordinates, hence yields a smaller set of coordinates and good numerical efficiency. On the other hand, closed-loop multi-body mechanical system the dynamic equations is a mixed differential-algebraic equation (Abbreviated DAE). Numerical integration methods of ordinary differential equations cannot to the DAE directly due to the poor numerical efficiency. Therefore, Baumgarte numerical integration method is used in this thesis, to acquired fast-integration and small constraint-error. Simulation results show that real-time dynamic simulation of HMMWV is achieved by using recursive dynamic equations and Baumgarte numerical integration method. The simulation code is implemented in Matlab software. Compare with the results of the dynamic analysis software ADAMS, the method presented in this thesis, in the same accuracy level, is more numerical efficiency than the ADAMS analysis.

碩士
國立高雄科技大學
電機工程系
107
In this study, various terrain information such as altitude and ground image are established by “Unity 3D Terrain” and “Unity 3D visual effect engine” are used to present gorgeous real visual effect performance. Moreover, the embedded PhysX physical simulation engine technology can better reconstruct the original Terrain features. In this paper, the bending mechanism is used to obtain the ski Angle with the snow surface. The pressure sensor is used to obtain the user's pressure at various points during skiing and the user's weight to simulate the physical quantity calculated during skiing. The Bluetooth transmission package is used to control the ski movement in Unity. After establishing the terrain and interactive hardware, then objects (skis, snow, trees) can be embedded in the reconstruction of the terrain with physical behaviors such as movement, collision, acceleration and rotation can be added. Then, the acceleration/angular rate calculated by the physical model of input trajectories of skiers through TCP/IP network communication protocol connecting master-slave at both ends and the virtual images of skis. Finally, let the user feel like real skiing with motion platform reaction. Keywords: PhysX, Unity, skiing physical simulation, Stewart Platform

碩士
正修科技大學
機電工程研究所
94
The thesis explores three subjects, including the optimal estimation of dimensional stability derivatives in linear model of unmanned air vehicle (UAV) longitudinal and lateral dynamics, the control law design of UAV autopilot, and the hardware-in-the-loop simulation (HILS) system setup for real-time control experiment. In stability derivatives identification, at first the raw data from UAV test flight were carefully preprocessed to obtain the fine input-output data in 6 flight sections for longitudinal motion and 8 flight sections for lateral motion. Second, the dimensional stability derivatives were optimal estimated by applying the nonlinear least squares method. In addition, the linear least squares method was also used to figure out the initial guess for the nonlinear least squares method. As a result, 5 longitudinal models and 7 lateral models with root mean square error (RMSE) less than 5 were identified. Third, the impulse responses of the identified models were checked. Those models which did not have proper cause-effect relations between the input and output were eliminated. At last the union optimization procedure was proposed to obtain the final linear state-space model of UAV longitudinal and lateral motion. The resulting model not only met the RMSE criterion for different flight sections but also had reasonable input-output relationship. In UAV autopilot design, four feedback loops, such as altitude (pitch angle) loop, velocity loop, attitude (roll angle) loop, and heading (yaw angle) loop were considered. The optimal PID (proportional-integral-derivative) control laws were designed to satisfy the time-domain specifications by using the Nonlinear Control Design Blockset in the computer-aided control system design software MATLAB/Simulink. In real-time control experiment, the HILS system consisted of one PC, four data acquisition cards, and one PXI (PCI eXtensions for Instrumentation) embedded real-time controller was setup successfully. The graphical programming language LabVIEW providing convenient and tight integration with software and hardware was applied for the measurement and control in HILS system. The individual simulations of controller and plant were running independently and the communications between controller and plant were under a fixed sampling frequency. The results of HILS revealed that the inevitable time delay resulting from program computation would seriously destroy the performance and stability of real-time control system especially when the sampling frequency is rather low; however, the non-real-time computer simulation cannot reveal this critical time-delay problem. The importance of HILS is definitely confirmed.

In recent years, hardware-in-the-loop (HIL) simulation has assumed a prominent role in the vehicle development process. A physical part, which may be a prototype at any stage of development, is tested, while the rest of the vehicle is represented by a mathematical model. Vehicle models used with hardware-in-the-loop must be capable of simulating an event in less time than it takes the event to occur in reality. Fast simulation necessitates a model that is represented by very efficient simulation code. This thesis presents a procedure for automatically generating this simulation code, given a description of the vehicle as input. For this work, a symbolic formulation procedure based on linear graph theory and the principle of orthogonality is used to generate governing equations for vehicle systems; this procedure forms the basis of the DynaFlexPro software package. In order to generate simulation code for vehicle dynamics studies, the DynaFlexPro component model template was extended to include rules for calculating intermediate variables and rules for calling external functions. These changes enabled the development of a tire component model, known as DynaFlexPro/Tire, that adds critically important (and computationally efficient) blocks to the overall vehicle simulation code. The combination of DynaFlexPro and DynaFlexPro/Tire allows analysts to construct a model for any vehicle topology and gives analysts great freedom to define how tire forces and moments will be calculated. Simulation code describing the vehicle model is automatically generated using symbolic computing techniques. The accuracy of the approach was validated by comparing results for DynaFlexPro vehicle models to results for equivalent models developed in a well-established tool for vehicle dynamics simulation (MSC.ADAMS). Two different vehicle models were constructed using DynaFlexPro and DynaFlex- Pro/Tire: a generic 4-wheeled vehicle with independent suspension and an articulated forestry skidder. Both models had an open-loop topology. When appropriate modeling variables were selected, each model was described by a minimal set of ordinary differential equations (ODEs) and the simulation code generated by DynaFlexPro was capable of being used for hardware-in-the-loop applications; the braking and handling behavior of the example models was simulated faster than real-time on a desktop PC with a 3.2 GHz Pentium 4 processor and 1 GB of RAM. For the same vehicle models, a different choice of modeling variables resulted in a mixed set of differential and algebraic equations (DAEs); in that case, HIL-capable simulation code could not be consistently generated. The approach works well for vehicle models described by ODEs, but more research is needed into the treatment of DAEs for real-time simulation of vehicle dynamics.

碩士
國立高雄第一科技大學
電機工程研究所碩士在職專班
105
Nowadays the terrain of Google Earth just only specially efficacy with texture maps but do not have any 3D physical model and the embedded objects (buildings landmarks and so on) and also do not have any physical collision. Hence in our research based on the Unity 3D Plug-In terrain information such as elevation above sea level longitude altitude and texture maps with terrain in any location of the World. Then the PhysX physical engine and OpenGL were employed for rebuilding terrain with physical collision. Otherwise after rebuilding the terrain embedding objects (aircraft buildings) into reconstructed terrain and complete the movement collision acceleration rotation and other physical behavior. Finally the Stewart platform control system combined with washout algorithm is presented with TCP/IP Protocol Suite linking two ends, let the acceleration and angle velocity generated from virtual image be the input so that the platform motion with the virtual screen of the aircraft to achieve the same movement behavior.

The main objective of this research is the development of a framework for the automatic generation of systems of kinematic and dynamic equations that are suitable for real-time applications. In particular, the efficient simulation of constrained multibody systems is addressed. When modelled with ideal joints, many mechanical systems of practical interest contain closed kinematic chains, or kinematic loops, and are most conveniently modelled using a set of generalized coordinates of cardinality exceeding the degrees-of-freedom of the system. Dependent generalized coordinates add nonlinear algebraic constraint equations to the ordinary differential equations of motion, thereby producing a set of differential-algebraic equations that may be difficult to solve in an efficient yet precise manner. Several methods have been proposed for simulating such systems in real time, including index reduction, model simplification, and constraint stabilization techniques. In this work, the equations of motion are formulated symbolically using linear graph theory. The embedding technique is applied to eliminate the Lagrange multipliers from the dynamic equations and obtain one ordinary differential equation for each independent acceleration. The theory of Gröbner bases is then used to triangularize the kinematic constraint equations, thereby producing recursively solvable systems for calculating the dependent generalized coordinates given values of the independent coordinates. For systems that can be fully triangularized, the kinematic constraints are always satisfied exactly and in a fixed amount of time. Where full triangularization is not possible, a block-triangular form can be obtained that still results in more efficient simulations than existing iterative and constraint stabilization techniques. The proposed approach is applied to the kinematic and dynamic simulation of several mechanical systems, including six-bar mechanisms, parallel robots, and two vehicle suspensions: a five-link and a double-wishbone. The efficient kinematic solution generated for the latter is used in the real-time simulation of a vehicle with double-wishbone suspensions on both axles, which is implemented in a hardware- and operator-in-the-loop driving simulator. The Gröbner basis approach is particularly suitable for situations requiring very efficient simulations of multibody systems whose parameters are constant, such as the plant models in model-predictive control strategies and the vehicle models in driving simulators.

Increasing environmental, economic, and political concerns regarding the consumption of fossil fuels have highlighted the need for more efficient and alternative energy solutions. Hybrid electric vehicles represent a near-term opportunity for reducing liquid fossil fuel consumption and green-house gas emissions in the transportation industry, and as a result, many automotive manufacturers have invested heavily in hybrid vehicle development. The increased complexity of hybrid electric vehicles over standard internal combustion engine-powered vehicles has subsequently placed significant emphasis on development of advanced control methods geared towards efficient energy management. Real-time optimization-based methods represent the current state-of-the-art in terms of hybrid vehicle control and energy management. This thesis summarizes the development of an optimization-based real-time control system – which determines the optimal instantaneous system operating point, including gear, traction split between front rear axles, and engine speed and torque – and its application to an all-wheel drive extended-range electric vehicle that uses a General Motor’s front-wheel drive 2-Mode electronic continuously variable transmission and an additional rear traction motor. The real-time control system was developed and validated using a plant model and preliminarily tested in the vehicle using a four-wheel drive chassis dynamometer. Results of simulation and in-vehicle testing demonstrate engine operation focused on high-efficiency operating regions and minimal use of the rear traction motor. Further testing revealed that a rule-based traction split system may be sufficient to replace the optimization-based traction split determination, and that the limited rear traction motor use was not a function of the motor itself, but rather an inherent result of the selected architecture.
Graduate

碩士
國立成功大學
航空太空工程學系
84
The objective of this research is to establish a personal computer ( PC ) level real - time simulation platform for the dynamics and control test offlight vehicles. Hardware structure of the platform includes two PCs, eachwith one digital -to- analog interface card AD-726 and one analog -to- digitalinterfacd card AD - 818, which are designed to run in parallel. Toexamine theintegrity of the platform, two representative systems weretested. One was a rigid spacecraft under slow attitude reorientation andthe other was a combat aircraft performing fast pasuit-evade maneuver. The first example simulated was the precision attitude control of a lowearth orbiting satellite under the effects of several environmental distur-bances. Three control laws were designed and implemented and the satellitewas assumed to be three-axis controlled. To integrate the control-dynamic soft- ware and the platform hardware for distributed parallel processing, the con-trol law was placed in one PC and the system dynamicstogether with theenvironment were hosted by another PC, and the two PC_x communiated numericaldata through interfacd cards in real-time. The requirement of the simulationis to steadily complete the attitude reorient-ation simulation in accordancewith the specified mission time ( in this case about 100 sec ). Tested in the second example was an integrated guidance and flight con-trol system of a combat vehicle. The guidance strategy was formulated fromthe model of two - person persuit - evade game theory and the flight controlsubsystem was designed by combining the input- output linearization techniqueand sliding control method. Under the same hardware structure as in thesatellite simulation, the guidance strategy was placed in one PC and the dyna-mics and control of the aircraft was implemented in another PC. The simulationrequires that the flight control subsystem maneuver the flight vehiclefollowing the command given by the guidance subsystem closely inreal-time. Comparing the results of the numerical experiments from the traditionalsingle PC simulation and the distributed parallel processing platform develop-ed in this research indicates that real-time or shorter simulation time andconceptually more realistic simulation environment can be achieved with thedeveloped platform.

This thesis investigates modeling and simulation of hybrid electric vehicles with particular emphasis on transient modeling and real-time simulation. Three different computer models, i.e. a steady state model, a fully-detailed transient model and a reduced-intensity transient model, are developed for a hybrid drive-train in this study. The steady-state model, which has low computational intensity, is used to determine the optimal battery size and chemistry for a plug-in hybrid drive-train. Simulation results using the developed steady state model show the merits of NiMH and Li-ion battery technologies. Based on the obtained results and the reducing cost of Li-ion batteries, this battery chemistry is used throughout this research. A fully-detailed transient model is developed to simulate the vehicle behaviour under different driving conditions. This model includes the dynamics of the power train components such as the engine, the power-electronic converters and vehicle controllers of all levels. The developed transient model produces an accurate representation of the drive-train including the switching behaviour of the power electronic converters. A reduced-intensity transient model (also referred to as a dynamic average model) is developed for real-time hardware-in-loop simulation of the vehicle. By reducing the computational demand of the detailed transient model using averaging techniques, the reduced-intensity model is implemented on a real-time simulator and is interfaced to an external subsystem such as an actual battery. The setup can be used to test existing and emerging battery technologies, which may not have an accurate mathematical model. Extensive tests are performed to verify the accuracy and validity of the results obtained from the developed hardware-in-loop simulation setup.

碩士
國立彰化師範大學
電子工程學系
100
The ECUs of Engine and braking system is the major research of the vehicle electronic control unit. It’s also highly correlated between vehicle performance, handling, and closely related to the safety and reliability. Certainly, the on-line and real time engine and anti-lock braking system simulation models can effectively assist the development of engine ECUs and completely eliminate energy waste and pollution problems in the developing progress. The software-hardware co-design is an innovative technique that introduces the hardwired computing blocks on the programmable logic devices to enrich the computing capacity on the traditional computing platforms. The NI CompactRIO, combining high-performance microprocessor, programmable logic device, and real-time OS coordinating with the software-hardware co-design techniques, should be helpful for the development of online real-time HIL engine and anti-lock braking system simulators. Thus, the on-line and real-time engine and anti-lock braking system HIL simulator are realized by VHDL and graphical programming language on the LabVIEW software development environment, and then implanted on the CompactRIO hardware platform to execute. Indeed, the execution results show that the dynamic behavior is highly close to the actual engine and anti-lock braking system behavior, and reaches the goals of engine and anti-lock braking system HIL simulator development.

Emerging technologies such as real-time travel information systems and automated vehicles (AVs) have profound impacts on driver decision-making behavior. While they generally have positive impacts by enabling drivers to make more informed decisions or by reducing their driving effort, there are several concerns related to inadequate consideration of cognitive and psychological aspects in their design. In this context, this dissertation analyzes different aspects of driver cognition and psychology that arise from drivers’ interactions with these technologies using physiological data collected in two sets of driving simulator experiments.

This research analyzes the latent cognitive and psychological effects of real-time travel information using electroencephalogram (EEG) data measured in the first set of driving simulator experiments. Using insights from the previous analysis, a hybrid route choice modeling framework is proposed that incorporates the impacts of the latent information-induced cognitive and psychological effects along with other explanatory variables that can be measured directly (i.e., route characteristics, information characteristics, driver attributes, and situational factors) on drivers’ route choice decisions. EEG data is analyzed to extract two latent cognitive variables that capture the driver’s cognitive effort during and immediately after the information provision, and cognitive inattention before implementing the route choice decision.

Several safety concerns emerge for the transition of control from the automated driving system to a human driver after the vehicle issues a takeover warning under conditional vehicle automation (SAE Level 3). In this context, this study investigates the impacts of driver’s pre-warning cognitive state on takeover performance (i.e., driving performance while resuming manual control) using EEG data measured in the second set of driving simulator experiments. However, there is no comprehensive metric available in the literature that could be used to benchmark the role of driver’s pre-warning cognitive state on takeover performance, as most existing studies ignore the interdependencies between the associated driving performance indicators by analyzing them independently. This study proposes a novel comprehensive takeover performance metric, Takeover Performance Index (TOPI), that combines multiple driving performance indicators representing different aspects of takeover performance.

Acknowledging the practical limitations of EEG data to have real-world applications, this dissertation evaluates the driver’s situational awareness (SA) and mental stress using eye-tracking and heart rate measures, respectively, that can be obtained from in-vehicle driver monitoring systems in real-time. The differences in SA and mental stress over time, their correlations, and their impacts on the TOPI are analyzed to evaluate the efficacy of using eye-tracking and heart rate measures for estimating the overall takeover performance in conditionally AVs.

The study findings can assist information service providers and auto manufacturers to incorporate driver cognition and psychology in designing safer real-time information and their delivery systems. They can also aid traffic operators to incorporate cognitive aspects while devising strategies for designing and disseminating real-time travel information to influence drivers’ route choices. Further, the study findings provide valuable insights to design operating and licensing strategies, and regulations for conditionally automated vehicles. They can also assist auto manufacturers in designing integrated in-vehicle driver monitoring and warning systems that enhance road safety and user experience.