Vehicle modeling and simulation have fast become the easiest and cheapest method for vehicle testing. No longer do multiple, intensive, physical tests need be performed to analyze the performance parameters that one wishes to validate. One component of the vehicle simulation that is crucial to the correctness of the result is the tire. Simulations that are run by a computer can be run many times faster than a real test could be performed, so the cost and complexity of the testing is reduced. A computer simulation is also less likely to have human errors introduced with the caveat that the data input into the model and simulation is accurate, or as accurate as one would like their results to be. Simulation can lead to real tests, or back up tests already performed. The repeatability of testing is a non-issue as well. Tire models are the groundwork for vehicle simulations and accurate results cannot be conceived without an accurate model. The reason is that all of the forces transmitted to and from the vehicle to the ground must occur at the tire contact patches. This presents the problem of obtaining a tire model. Tire companies do not readily give out tire data since the tire industry is still as much "black art" as it is science. For tire data one must begin with a testing apparatus. The test rig must be accurate and must have been validated before results can be used. This thesis presents the process of the design and construction of a portable tire test rig. It then will discuss tire testing procedures and validation techniques. The resulting data shows good correlation between test data and known tire test data from flat track testing provided by a tire manufacturer. Then, a simple rollover study of a military truck will be compiled in TruckSim. Lastly, a control method for the rollover case will be designed and implemented. The results of the roll control simulation are positive. The study shows an increase in dynamic roll stability due to the implementation of the control algorithm. / Master of Science

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Motor vehicle accidents involving pedestrians are some of the most common and lethal forms of injury for children in the United States. Among younger children, a common mechanism of action for severe trauma is when a vehicle runs over the child in a forward or backward motion at low speed resulting in a blunt crush injury. This typically occurs in non‐traffic settings including driveways, sidewalks, and roadways. Such incidents have been referred to in many different ways in the literature but for the purposes of this paper will be referred to as low speed vehicle run‐overs. This is a retrospective chart review carried out at Phoenix Children’s Hospital in affiliation with the University of Arizona College of Medicine‐Phoenix that categorizes and examines the injuries sustained by patients involved in low speed vehicle runovers occurring between December 2007 and August 2013. Fifty‐five pediatric patients were included with a median age of 24 months and 6 of these patients were fatally injured. Internal injuries were common overall and significantly more common in children ≤24months. Over half of the cohort sustained fractures, with a 24% incidence of skull fractures. All fatalities were the result of traumatic brain injury. Twenty percent of victims required operative intervention. It was concluded that the severity of these types of incidents varies from minimal to life threatening and best care requires close and thorough evaluation by the trauma and emergency department teams.

The work presented in this thesis is dedicated to the study of vehicle rollover and the tyre and suspension characteristics influencing it. Recent data shows that 35.4% of recorded fatal crashes in Sports Utility Vehicles (SUVs) included vehicle rollover. The effect of rollover on an SUV tends to be more severe than for other types of passenger vehicle. Additionally, the number of SUVs on the roads is rising. Therefore, a thorough understanding of factors affecting the rollover resistance of SUVs is needed. The majority of previous research work on rollover dynamics has been based on low fidelity models. However, vehicle rollover is a highly non-linear event due to the large angles in vehicle body motion, extreme suspension travel, tyre non-linearities and large forces acting on the wheel, resulting in suspension spring-aids, rebound stops and bushings operating in the non-linear region. This work investigates vehicle rollover using a complex and highly non-linear multi-body validated model with 165 degrees of freedom. The vehicle model is complemented by a Magic Formula tyre model. Design of experiment methodology is used to identify tyre properties affecting vehicle rollover. A novel, statistical approach is used to systematically identify the sensitivity of rollover propensity to suspension kinematic and compliance characteristics. In this process, several rollover metrics are examined together with stability considerations and an appropriate rollover metric is devised. Research so far reveals that the tyre properties having the greatest influence on vehicle rollover are friction coefficient, friction variation with load, camber stiffness, and tyre vertical stiffness. Key kinematic and compliance characteristics affecting rollover propensity are front and rear suspension rate, front roll stiffness, front camber gain, front and rear camber compliance and rear jacking force. The study of suspension and tyre parameters affecting rollover is supplemented by an investigation of a novel anti-rollover control scheme based on a reaction wheel actuator. The simulations performed so far show promising results. Even with a very simple and conservative control scheme the reaction wheel, with actuator torque limited to 100Nm, power limited to 5kW and total energy consumption of less than 3kJ, increases the critical manoeuvre velocity by over 9%. The main advantage of the proposed control scheme, as opposed to other known anti-rollover control schemes, is that it prevents rollover whilst allowing the driver to maintain the desired vehicle path.

The goal of this thesis is to develop an active front steering(AFS) control system which can apply to ordinary vehicle. This AFS control system stabilizes the driving vehicle and reduces the possibility of rollover. This thesis uses magic formula tire model and constructs a vehicle model with eight degrees of freedom to study the dynamic behavior of the real driving vehicle. This thesis constructs a vehicle model with three degrees of freedom and eight degree of freedom, compare with two vehicle model, we adopt eight vehicle model in this thesis. The advantages of PI controller are low cost and easy to modify, so this thesis adopts PI controller as the control strategy. This study uses four simulate methods and compares the simulated results to develop the AFS control system which can apply to ordinary vehicle.

The rising statistics of fatal and non-fatal injuries involving an all-terrain vehicle has called for an analysis of the accumulated data from the past years. The analysis has led to the conclusion that in the past years, the fatal and non-fatal injuries have been rising rapidly in spite of the consent decrees which were brought into effect from 1988-1998 by the consumer product safety commission. A necessity to provide increased safety while riding an all-terrain vehicle is recognized. Rollover protective structures which were used with successful results in curbing the injuries on agricultural tractors have been identified as having a potential to serve the purpose. A conceptual design of an automatically deployable rollover protective structure has been dealt with, in the thesis.

The thesis deals with the issue of measuring the height of the center of gravity of SUV´s. The first part of thesis is devoted to the issue of center of gravity and the influence of the height of the center of gravity on driving stability. Furthermore, individual methods of measuring the height of the center of gravity in passenger cars are discussed. The analytic part of the thesis is devoted to experimental measurement of the height of the center of gravity of selected SUV´s at different vehicle load, by the method of tilting the vehicle on the axle. The results of the measurements showed that the height of the center of gravity for vehicles with a capacity for five people is in the range from 606 to 697 mm. The lowest value belongs to the vehicle Toyota RAV4 Hybrid, when loaded by the driver. The highest value was found for the vehicle Kia Sportage, when loaded by three passengers. The Landover Defender, which is vehicle, that has a capacity for nine people, was found to have a height of center of gravity ranging from 705 to 874 mm. The lowest value was found when loaded by the driver, the highest value when loaded by nine passengers. Only for the Nissan Qashqai was the growing dependence between the load increase and the height position of the vehicle's center of gravity confirmed. A similar trend was found for the Toyota RAV4 Hybrid, Jeep Compass and Landover Defender. The determined values can be used in the analysis of traffic accidents of SUV’s.