The kinematic analysis of an articulated twin body, four-wheel, robotic vehicle is presented. Polaris, a research platform and contending robotic vehicle in the Intelligent Ground Vehicle Competition (IGVC) at Virginia Tech, was redesigned in 2006 to improve the mobility of the vehicle by incorporating an innovative four-bar linkage that connects the two bodies. The new linkage design minimizes vehicle off-tracking by allowing the rear wheels to closely track the path of the front wheels. This thesis will outline the theoretical kinematic model of the four-bar linkage as applied to a twin-bodied, differentially driven vehicle. The kinematic model is validated through computer simulation as well as experimentation on a fully operational robotic vehicle. The kinematic model presented here outlines the foundations for an autonomous, four-wheel drive, multi-body control system and opens avenues for dynamically controlling the tracking of the vehicle's rear body with an actuated linkage configuration. / Master of Science

Este estudo contribui para um melhor entendimento do desempenho de veículos combinados em interseções de rodovias secundárias. A hipótese de que as normas nacionais e estrangeiras não são adequadas para permitir a compatibilidade entre a circulação desses veículos e a geometria horizontal de interseções em nível no Brasil é investigada. Através de processo de simulação demonstramos que, com relação ao arraste, o comportamento de veículos com mais de uma articulação pode ser bom, e por vezes melhor que o de veículos com apenas uma articulação, se considerados certos aspectos operacionais e de engenharia. Contamos que as autoridades de tráfego brasileiras passem a ser menos restritivas para com a regulamentação de dimensões de veículos combinados longos, tendo em vista o aumento de produtividade alcançado com o seu uso. Como a regulamentação brasileira tem sido tradicionalmente influenciada por normas e recomendações estrangeiras, tanto para o projeto e construção de vias como para a regulamentação de veículos, procuramos caracterizar as diferenças de comportamento dos veículos e as respectivas discrepâncias em relação às normas nacionais e estrangeiras. Esta avaliação visa fornecer elementos para um julgamento mais apropriado das condições brasileiras, para que possamos elaborar nossas próprias normas, promovendo melhores condições de segurança aos usuários dos sistemas de transporte rodoviário. / This study contributes to a better understanding of combination vehicle performance on secondary roadway intersections. The hypothesis that national and foreign rules are inadequate to provide compatibility of the traffic of these vehicles with the horizontal geometry of at grade intersections in Brazil is investigated. With respect to offtracking, and with due consideration to certain operational and engineering concerns, we have demonstrated, through a simulation process, that the behavior of vehicles with double articulation can be good, and at times even better than the behavior of single articulated vehicles. We expect that Brazilian roadway authorities will become Iess restrictive toward the regulation of longer combination vehicles, taking into consideration the increase in productivity achieved with their use. Since Brazilian regulatory agencies have been traditionally influenced by foreign standard rules and recommendations for highway design and construction, as well as regulation of vehicles, we have tried to characterize the differences in vehicle performance and the respective discrepancies in relation to national and foreign standards. The main objective of this evaluation is to present the elements that permit a more appropriate judgment of Brazilian conditions, so that we will be able to elaborate compatible rules and procedures, thus providing better safety conditions for users of roadway transportation systems.

Este estudo contribui para um melhor entendimento do desempenho de veículos combinados em interseções de rodovias secundárias. A hipótese de que as normas nacionais e estrangeiras não são adequadas para permitir a compatibilidade entre a circulação desses veículos e a geometria horizontal de interseções em nível no Brasil é investigada. Através de processo de simulação demonstramos que, com relação ao arraste, o comportamento de veículos com mais de uma articulação pode ser bom, e por vezes melhor que o de veículos com apenas uma articulação, se considerados certos aspectos operacionais e de engenharia. Contamos que as autoridades de tráfego brasileiras passem a ser menos restritivas para com a regulamentação de dimensões de veículos combinados longos, tendo em vista o aumento de produtividade alcançado com o seu uso. Como a regulamentação brasileira tem sido tradicionalmente influenciada por normas e recomendações estrangeiras, tanto para o projeto e construção de vias como para a regulamentação de veículos, procuramos caracterizar as diferenças de comportamento dos veículos e as respectivas discrepâncias em relação às normas nacionais e estrangeiras. Esta avaliação visa fornecer elementos para um julgamento mais apropriado das condições brasileiras, para que possamos elaborar nossas próprias normas, promovendo melhores condições de segurança aos usuários dos sistemas de transporte rodoviário. / This study contributes to a better understanding of combination vehicle performance on secondary roadway intersections. The hypothesis that national and foreign rules are inadequate to provide compatibility of the traffic of these vehicles with the horizontal geometry of at grade intersections in Brazil is investigated. With respect to offtracking, and with due consideration to certain operational and engineering concerns, we have demonstrated, through a simulation process, that the behavior of vehicles with double articulation can be good, and at times even better than the behavior of single articulated vehicles. We expect that Brazilian roadway authorities will become Iess restrictive toward the regulation of longer combination vehicles, taking into consideration the increase in productivity achieved with their use. Since Brazilian regulatory agencies have been traditionally influenced by foreign standard rules and recommendations for highway design and construction, as well as regulation of vehicles, we have tried to characterize the differences in vehicle performance and the respective discrepancies in relation to national and foreign standards. The main objective of this evaluation is to present the elements that permit a more appropriate judgment of Brazilian conditions, so that we will be able to elaborate compatible rules and procedures, thus providing better safety conditions for users of roadway transportation systems.

The dissertation deals with application of simulated swept paths of vehicles to road designs. Using software which generates simulated swept paths makes new demands on the designer, but Czech regulations do not stipulate the appropriate method of applying swept paths. The theoretical part of the dissertation analyses the theory of how a vehicle moves when passing through a horizontal road curve and a method of calculating a necessary extent of widening the road. The practical part compares swept paths generated by various software programs and differences between them. In order to verify the shapes and dimensions of the swept paths generated, the swept path of a real vehicle was measured. This swept path was then compared with the one generated, and the differences between them were evaluated. One of the software programs was chosen as a reference program, and its output was applied to a road design pursuant to valid regulations. The results obtained within the dissertation were used to develop certified methodology titled: „Methodology of widening road lanes in horizontal curves and of application of vehicles’ swept paths “.