O principal propósito deste trabalho é desenvolver e caracterizar o veículo robótico ℏelvis III, para ser usado no desenvolvimento de pesquisas na área de controle e navegação de robôs móveis. O sistema de propulsão foi caracterizado para determinar a velocidade real do veículo em quatro tipos diferentes de terrenos (Asfalto, grama, grama-terra e terra). Também foi caracterizado o sistema de esterçamento mediante o modelo cinemático da bicicleta, onde se obteve a relação entre a posição do servo motor encarregado do esterçamento do veículo e o valor do ângulo de esterçamento de uma bicicleta. Foram determinados os valores dos erros CEP (Circular Error Probability) e SEP (Spherical Error Probability) do GPS (Global Positioning System) embarcado no veículo mediante dois testes: um em São Carlos – SP (Brasil) e outro em Villavicencio – Meta (Colômbia). Nesses testes foi caracterizada a IMU (Inertial Measurement Unit) embarcada no veículo, além de verificado o efeito da luz solar no funcionamento do sensor tipo LIDAR (Laser Imaging Detection and Ranging) embarcado no helvis III. Por último, pode-se definir a dinâmica do veículo à frente, com a determinação seu centro de massa, e é apresentado o comportamento das forças sob as rodas quando o veículo fica parado ou em movimento sobre terrenos que geram uma inclinação em algum dos eixos cartesianos. / The main objective of this work is the development and characterization of a robotic vehicle ℏelvis III in order to use it in the development of researches focused on the fields of mobile robotics control and navigation. Initially the propulsion system was characterized in order to determine the real velocity of vehicle in real conditions (four different kinds of grounds were used). In addition to this, the steering system was also characterized by applying the well-known bicycle kinematic model. During these experimental tests we could find the relation between the position of the servo-motor and the value of steering angle of the bicycle model. The real values of CEP (Circular Error Probability) and SEP (Spherical Error Probability) errors of the vehicle embedded GPS (Global Positioning System) were determined based on two experiments: the first one was carried out in São Carlos – SP (Brazil) and the second one in Villavicencio – Meta (Colombia). During the GPS experiments we could also characterize the vehicle embedded IMU (Inertial Measurement Unit). Then we could observe and measure the effect of solar light on the LIDAR sensor (Laser Imaging Detection and Ranging) performance. Finally, the forward vehicle dynamics is described, with the determination of the center of mass of the vehicle and the observation of the normal forces behavior in the vehicle wheels when it is stopped or moved on an inclined floor.

The thesis describes function and characteristics of spring and damper, their particular way and margin of influence on vehicle behavior in selected riding maneuvers. The goal is to maintaining maximal grip, control, and achieve predictable vehicle handling.

This work deals with the assessment of the yaw moment control via active differential effects to the heavy commercial vehicle dynamics. Summarized are the findings about design of active differential, control algorithms and theoretical assumptions about overall effects to the vehicle dynamics. According to the described theory the own concept of the active differential for experimental heavy commercial vehicle is proposed. The main part of the work is focused on the effects of the active differential on vehicle manoeuvrability, controllability, stability and limits analysis. For this purpose, multibody dynamic model of the complete vehicle with standard open differential is assembled and results of the selected manoeuvre simulations validated by measurements of the real vehicle characteristics. The validated vehicle model is then extended by the model of the active differential with control algorithm. According to the simulations results the theoretical presumptions are confirmed and the effects of the active differential on vehicle dynamics in steady and transition states are evaluated. Based on the described findings the overall improvement of the vehicle dynamics by this technology, feasibility of the proposed concept and main advantages and disadvantages are evaluated.

The aim of this master’s thesis is to use virtual reality to analyze and display the vehicle and the quantities characterizing the dynamic properties of the vehicle. The simulation software tools are used Matlab/Simulink and Virtual Reality Toolbox. The measured or calculated data will the input for the simulation. The dissertation is aimed to create a virtual scene and a dynamic system for the movement of file.

This work deals with the impact of selected electronic chassis systems of modern vehicles, their driving dynamics. The general aim of this work is to create the basic methodology for assessing casualties of the influence of these systems. The thesis is describing functions and effects antilock and stability systems on vehicle dynamics. Below are possible methods and systems for determining the influence on accident plot. As part of the study was performed measuring the impact of anti-lock system on the vehicle. The result of this work is the basic methodology to the analysis of road accidents involving vehicles with electronic chassis systems.

Ce travail de thèse est une contribution à l’analyse de santé structurale de la caisse de véhicules militaires terrestres à roues. Appartenant à la gamme 20 - 30 tonnes, de tels véhicules sont déployés dans des contextes opérationnels variés où les conditions de roulage sont sévères et difficilement caractérisables. De plus, faisant face à la concurrence, la fonction mobilité des véhicules est acquise auprès de fournisseurs et n’est plus développée par Nexter Systems. De ce fait, la définition complète de cette fonction n’est plus connue. S’appuyant sur ce contexte, l’objectif principal de la thèse est d’aborder l’état de santé de la structure porteuse par approche probabiliste, afin de maitriser les techniques de calcul permettant la prise en compte de l’aléa intrinsèque des chargements liés à la diversité d’emploi des véhicules militaires terrestres. En particulier, les stratégies les plus pertinentes pour propager les incertitudes de roulage au sein d’un modèle mécanique d’un véhicule terrestre sont définies. Ces travaux décrivent comment il est possible d’exploiter une grandeur d’intérêt au sein du véhicule dans un objectif d’évaluation de la fiabilité par rapport à un critère de dommage donné. Une application sur un démonstrateur entièrement conçu par Nexter Systems illustre l’approche proposée. / This thesis is a contribution to the structural health analysis of the body of ground military vehicles. Belonging to the 20 - 30 tons range, such vehicles are deployed in a variety of operational contexts where driving conditions are severe and difficult to characterize. In addition, due to a growing industrial competition, the mobility function of vehicles is acquired from suppliers and is no longer developed by Nexter Systems. As a result, the complete definition of this function is unknown. Based on this context, the main objective of this thesis is to analyze the health of the vehicle body using a probabilistic approach in order to control the calculation techniques allowing to take into account the random nature of loads related to the use of ground military vehicles. In particular, the most relevant strategies for propagating uncertainties due to the terrain within a vehicle dynamics model are defined. This work describes how it is possible to manage an observation data measured in the vehicle for the purpose of assessing the reliability with respect to a given damage criterion. An application on a demonstrator entirely designed by Nexter Systems illustrates the proposed approach.

Als elastische Koppelglieder üben Elastomere im Fahrwerk maßgeblichen Einfluss auf die Elastokinematik der Radaufhängung und damit auf die Radstellgrößen aus. Bereits einfache zylindrische Probekörper zeigten in der Vergangenheit Veränderlichkeit der Federsteifigkeiten bei mehrachsiger Belastung auf. Daraus ließ sich ableiten, dass das Bauteilverhalten von zylindrischen Elastomerkörpern, bzw. Fahrwerklagern, schwer vorhersagbar ist und dieser Effekt durch die Verwendung komplexer Geometrien zusätzlich beeinflusst wird. Eigens im Rahmen dieser Arbeit entwickelte Prüfstände ermöglichten die Untersuchung von statischen, mehrachsigen Belastungen sowie zyklischen, einachsigen Belastungen zweier Fahrwerklager einer typischen Vorderradaufhängung, dem Mc-Pherson-Federbein. Für beide Lagertypen wurden derart signifikante Federsteifigkeitsänderungen unter mehrachsiger Belastung beobachtet, dass ein Einfluss auf die Elastokinematik sicher schien. Unter einachsiger, zyklischer Belastung bestätige sich, dass einfache rheologische Ersatzmodelle, wie der Ansatz nach Kelvin-Voigt für eine Modellierung des viskoelastischen Materialverhaltens weiterhin Gültigkeit besitzen. Ein in einem Mehrkörpersimulationsprogramm erstelltes Gesamtfahrzeugmodell zeigte zunächst für die Auslegung der Prüfstände relevante Beanspruchungen in den Fahrwerklagern auf und diente weiterhin als Grundlage für die Untersuchung des Einflusses von Wechselwirkungen auf die Radstellgrößen. Dazu behandelt die Arbeit die Modellierung eines neuen Fahrwerklagermodells innerhalb dieser MKS-Umgebung. Dieses Modell bietet dem Nutzer die Möglichkeit für eine Abbildung von Wechselwirkungen an zylindrischen, zyklisch beanspruchten Bauteilen. Ein spezielles Fahrmanöver zeigte den Einfluss der Wechselwirkungen auf die Radstellgrößen auf und zeigte, dass die Berücksichtigung von Wechselwirkungen für eine Fahrwerkauslegung relevant ist. Darüber hinaus wurde mit kommerziell verfügbaren Materialmodellen für die Beschreibung es Materialverhaltens von Elastomeren innerhalb der Finite-Elemente-Methode aufgezeigt, dass bei einachsiger Belastung die Federsteifigkeiten der Fahrwerklager auf Grundlage der in der Literatur üblichen Auslegungsgleichungen näherungsweise abgebildet werden können, jedoch für mehrachsige Spannungszustände keine hinreichende Aussage über das Bauteilverhalten getroffen werden kann. Hier wurde weiterer Forschung- bzw. Erweiterungsbedarf an den FE-Programmen aufgezeigt.

A vast expansion is found in the field of automotive electronic systems. The expansion iscoupled with a related increase in the demands of power and design. Now, this is goodarena of engineering opportunities and challenges. One of the challenges faced, isdeveloping fault tolerant systems, which increases the overall automotive and passengersafety. The development in the field of automotive electronics has led to the innovationof some very sophisticated technology. However, with increasing sophistication intechnology also rises the requirement to develop fault tolerant solutions.As one of many steps towards developing a fault tolerant system, this thesis presents anexhaustive fault analysis. The modeling and fault analysis is carried out for a vehicle withfour in-wheel motors. The primary goal is to collect as many of the possible failuremodes that could occur in a vehicle. A database of possible failure modes is retrievedfrom the Vehicle Dynamics research group at KTH. Now with further inputs to thisdatabase the individual faults are factored with respect to change in parameters of vehicleperformance. The factored faults are grouped with respect to similar outputcharacterization.The fault groups are modeled and integrated into a vehicle model developed earlier inMatlab/Simulink. All the fault groups are simulated under specific conditions and theresults are obtained. The dynamic behavior of the vehicle under such fault conditions isanalyzed. Further, in particular the behavior of the vehicle with electronic stabilitycontrol (ESC) under the fault conditions is tested. The deviation in the vital vehicleperformance parameters from nominal is computed.Finally based on the results obtained, a ranking system termed Severity Ranking System(SeRS) is presented. The severity ranking is presented based on three essential vehicleperformance parameters, such as longitudinal acceleration ( ), lateral acceleration ( )and yaw rate ( ̇ ). The ranking of the faults are classified as low severity S1, mediumseverity S2, high severity S3 and very high severity S4. A fault tolerant system must beable to successfully detect the fault condition, isolate the fault and provide correctiveaction. Hence, this database would serve as an effective input in developing fault tolerantsystems.

The main goal of this work is to gain knowledge of how and to what extent state-of-the-artsimulation tools can be used in a conceptual development phase for vehicle dynamics control atVolvo Car Corporation (VCC).The first part of the thesis deals with an evaluation of vehicle dynamics simulation tools and theiruses. The three simulation tools selected for the study, namely Mechanical Simulation CarSim 8.2.1,IPG CarMaker 4.0.5, and VI-Grade CarRealTime V14, are briefly described and discussed. In order toevaluate and compare these tools with respect to application for vehicle dynamics control, a criterialist is developed covering aspects such as tool requirements and intended usage. Based on thecriteria list and certain identified drawbacks, a ranking of the tools is made possible. Furthermore,the process of developing vehicle models for the different tools is discussed in detail, along with theprocedure of validating the vehicle models.In the second part, the concept of Collision Avoidance Driver Assistance (CADA) function isintroduced and possible approaches for developing CADA functions are discussed in brief. It isimportant to note that the CADA functions in this work are based on cornering the vehicle i.e.maneuvering around the threat, rather than solely reducing vehicle speed. A number ofimplementations of the functions are developed in Simulink. A frequency analysis of a simplifiedlinear vehicle model is performed to investigate the influence of steering, differential braking, andtheir combination on the resultant lateral displacement of the vehicle during an evasive maneuver.The developed CADA functions are then simulated using the vehicle simulation tools. Two specificmetrics - Lateral Displacement gain and DeltaX - are formulated to evaluate the effectiveness of theCADA functions. Based on these metrics, the assistance obtained due to the functions for a specificevasive maneuver is compared.From the evaluation process of the three tools, two were considered suitable for the purpose ofsimulating collision avoidance functions. The evaluation of the CADA functions demonstrates thatcombined assistive steering with differential braking provides considerable assistance in order toavoid collisions. The simulation results also present interesting trends which provide a usefuldirection regarding the conditions for intervention by such collision avoidance functions during anevasive maneuver. The use of simulation tools makes it possible to observe these trends and utilizethem in the development process of the functions.

Virginia's Smart Road, to be completed by early 2000, is a test bed for numerous research activities including snow and ice control, remote sensor testing, snow removal management, safety and human factors, and vehicle dynamics. An all-weather testing system will feature 75 automated snowmaking towers. In order to provide timely and repeatable weather scenarios, equipment operators will need to understand fully the limitations and capabilities of the snowmaking system. The research presented herein addresses the hydraulic and hydrologic variables and design methodology to implement efficient snowmaking at a transportation research facility. Design variables include nozzle configuration, water pressure and flowrate, compressed air pressure and flowrate, tower orientation, snow inducer concentration, water and compressed air temperature, and ambient weather conditions. Testing and data collection was performed at the Snow Economics, Inc. research and development site at Seven Springs Mountain Resort in Champion, PA. The results of this work will be used to guide the operators of the Smart Road on the most efficient use of the snowmaking equipment. / Master of Science