O objetivo desta dissertação foi estudar dispositivos para contenção de veículos desgovernados por falta de freios em declives longos e íngremes. Para tanto, fez-se uma revisão abrangente da literatura especializada e coletaram-se dados em testes realizados na área de escape construída no km 42,7 da pista sul da Via Anchieta, onde existe um declive de 12,8 km de extensão. A pesquisa relatada nesta dissertação focaliza três aspectos principais: a eficiência do dispositivo em deter caminhões sem freios, a localização do dispositivos e a determinação da velocidade segura de operação de caminhões nesse declive. Dados empíricos da desaceleração dos caminhões no dispositivo foram coletados com auxílio de GPS, o que permitiu estudar o comportamento dos caminhões dentro da caixa de retenção. Os dados coletados foram usados para a calibração de um modelo capaz de estimar a desaceleração média proporcionada pelo dispositivo em função da velocidade de entrada e do número de eixos do caminhão. Para a análise da localização do dispositivo, propôs-se um modelo que leva em consideração o perfil vertical do declive, a velocidade dos caminhões, a temperatura dos freios e a frequência de acidentes com veículos desgovernados ao longo do declive. A determinação da estratégia ótima de condução no declive consistiu em determinar a máxima velocidade que os caminhões podem percorrer o declive sem que os freios sofram superaquecimento. Os parâmetros usados na análise foram a massa bruta total do veículo e as reduções da sua caixa de câmbio. Foram estabelecidas velocidades e marchas máximas para 16 tipos de caminhão. Os resultados obtidos mostram que este tipo de dispositivo é capaz de deter caminhões desgovernados com segurança e podem subsidiar projetos de novas áreas de escape no Brasil. / The objective of the dissertation was to study devices for arresting runaway trucks on long and steep downgrades. A comprehensive review of the literature was carried out and empirical data were collected by means of real life trials at an arrester bed build at a 12.8 km downgrade on the southward lanes of Via Anchieta, the old highway connecting the cities of São Paulo and Santos, in Brazil. The research reported focused on three major aspects: arresting capability of the escape area, location of the escape area and safe operating speeds for trucks on this downgrade. Truck deceleration data were collected during the trials by means of GPS equipment installed in the vehicles and were used to determine truck behavior within the arrester bed. A mathematical model, which allows the estimation of average deceleration as a function of entry speed and number of axles, was fitted to the observed data. The location study proposed a method to establish the points along the downgrade where arrester beds are needed, based on road profile, truck speed, brake temperature and accident data. Optimal driving strategies for truck drivers to negotiate safely the downgrade were also studied, in order to determine the downgrade maximum speed that would avoid brake overheating. The parameters used in this analysis were gross vehicle mass and gearbox characteristics. Safe maximum downgrade speeds and gears were established for 16 truck models. The results, which showed that arrester beds are capable of safely stopping runaway trucks in long and steep downgrades, may also be used to assist the design of new arrester beds in Brazil.

A presente dissertação visa analisar o desempenho na frenagem de um cavalo mecânico e semi-reboque que utiliza o sistema ABS (Antilock Braking System). Foi desenvolvido um modelo virtual de simulação utilizando a técnica dos sistemas multicorpos (Multibody System) do SimMechanics, um toolbox do Matlab/Simulink. No modelo virtual do veículo combinado foram considerados os parâmetros geométricos e mecânicos dos chassis, das suspensões, dos freios, contato pneu-pavimento e a válvula sensível à carga. São obtidas as forças normais dinâmicas no contato pneu pavimento quando o veículo está desacelerando de 20m/s até a parada completa, estas forças normais dinâmicas são entradas de uma sub-rotina em Simulink onde são calculadas as forças de frenagem, quando os freios tipo S carne são acionados. São realizadas simulações de frenagens em linha reta em pistas de média aderência (0,4) e alta aderência (0,8). As eficiências são obtidas quando o cavalo mecânico utiliza a configuração fixa de ABS tipo 6S/6M e o semi-reboque utiliza diversas configurações de ABS tipos: 2S/1M (e 4,6); 2S/2M (e 4,6); 4S/2M (e4); 4S/2M (e6); 4S/3M (e4); 4S/3M (e6); 4S/4M (e4) e 4S/4M (e6) e 6S/6M. O veículo é simulado também freando sem sistema ABS e a eficiência resultante comparada com as obtidas anteriormente. Os resultados são apresentados em figuras que mostram as forças normais dinâmicas ao pavimento, as aderências utilizadas pelos pneus e as eficiências atingidas pelas diversas configurações de ABS utilizadas no semi-reboque. Conclui-se de forma geral que configurações de ABS com mais sensores e válvulas moduladoras produzem uma eficiência maior e que a utilização de qualquer configuração de ABS como sistema complementar do sistema de freios de serviço, aumenta a eficiência de frenagem que é sempre superior ao do veículo sem sistema ABS. Esses resultados ajudam na preservação da dirigibilidade e estabilidade do veículo combinado, contribuindo assim na prevenção de acidentes de trânsito em situações de emergência. / This dissertation reports on the development of a simulation model for the analysis of the braking performance of tractor-semitrailer vehicles that use the ABS (Antilock Braking System). The model was developed using the virtual simulation technique of multibody systems with SimMechanics, a toolbox of Matlab/Simulink. In this simulation model the mechanical and geometrical parameters of the chassis, suspensions, brakes, adhesion coefficient, and load sensing valve were considered. When the vehicle is decelerating, the normal forces between the tire and road surface are obtained by the virtual model. These forces are the input of a subroutine in which the braking forces are calculated when the S Came brakes are triggered. Simulations of braking on straight line in road were made for average adhesion coefficient (0.4) and high adhesion coefficient (0.8). Efficiencies were obtained when the tractor used fixed ABS configuration of a 6S/6M type, and the semitrailer used the ABS type: 2S/lM (and 4.6); 2S/2M (and 4.6); 4S/2M (e4); 4S/2M (e6); 4S/3M (e4); 4S/3M (e6); 4S/4M (e4) and 4S/4M (e6) and 6S/6M. The results are presented in figures which show, the normal dynamic forces between tire and road, adhesions used by the tires and the efficiencies achieved by different ABS configurations installed in the semi-trailer. It is possible to conclude that in general ABS configurations with more sensors and modulating valves produce higher efficiency and the use of any configuration as a complementary system of the ABS brake system service increases the braking efficiency, which is always higher than that of a vehicle without ABS. The results help preserving the vehicle stability and maneuverability, preventing road accidents in emergency situations.

O objetivo desta dissertação foi estudar dispositivos para contenção de veículos desgovernados por falta de freios em declives longos e íngremes. Para tanto, fez-se uma revisão abrangente da literatura especializada e coletaram-se dados em testes realizados na área de escape construída no km 42,7 da pista sul da Via Anchieta, onde existe um declive de 12,8 km de extensão. A pesquisa relatada nesta dissertação focaliza três aspectos principais: a eficiência do dispositivo em deter caminhões sem freios, a localização do dispositivos e a determinação da velocidade segura de operação de caminhões nesse declive. Dados empíricos da desaceleração dos caminhões no dispositivo foram coletados com auxílio de GPS, o que permitiu estudar o comportamento dos caminhões dentro da caixa de retenção. Os dados coletados foram usados para a calibração de um modelo capaz de estimar a desaceleração média proporcionada pelo dispositivo em função da velocidade de entrada e do número de eixos do caminhão. Para a análise da localização do dispositivo, propôs-se um modelo que leva em consideração o perfil vertical do declive, a velocidade dos caminhões, a temperatura dos freios e a frequência de acidentes com veículos desgovernados ao longo do declive. A determinação da estratégia ótima de condução no declive consistiu em determinar a máxima velocidade que os caminhões podem percorrer o declive sem que os freios sofram superaquecimento. Os parâmetros usados na análise foram a massa bruta total do veículo e as reduções da sua caixa de câmbio. Foram estabelecidas velocidades e marchas máximas para 16 tipos de caminhão. Os resultados obtidos mostram que este tipo de dispositivo é capaz de deter caminhões desgovernados com segurança e podem subsidiar projetos de novas áreas de escape no Brasil. / The objective of the dissertation was to study devices for arresting runaway trucks on long and steep downgrades. A comprehensive review of the literature was carried out and empirical data were collected by means of real life trials at an arrester bed build at a 12.8 km downgrade on the southward lanes of Via Anchieta, the old highway connecting the cities of São Paulo and Santos, in Brazil. The research reported focused on three major aspects: arresting capability of the escape area, location of the escape area and safe operating speeds for trucks on this downgrade. Truck deceleration data were collected during the trials by means of GPS equipment installed in the vehicles and were used to determine truck behavior within the arrester bed. A mathematical model, which allows the estimation of average deceleration as a function of entry speed and number of axles, was fitted to the observed data. The location study proposed a method to establish the points along the downgrade where arrester beds are needed, based on road profile, truck speed, brake temperature and accident data. Optimal driving strategies for truck drivers to negotiate safely the downgrade were also studied, in order to determine the downgrade maximum speed that would avoid brake overheating. The parameters used in this analysis were gross vehicle mass and gearbox characteristics. Safe maximum downgrade speeds and gears were established for 16 truck models. The results, which showed that arrester beds are capable of safely stopping runaway trucks in long and steep downgrades, may also be used to assist the design of new arrester beds in Brazil.

<p>U doktorskoj disertaciji razmatra se unapređenje konstrukcije magnetoreolo&scaron;ke disk kočnice sa ciljem povećanja vrednosti ukupnog kočnog momenta. Radi potpunog razumevanja međusobnog odnosa materijala i magnetskog polja na prvom mestu je izvr&scaron;eno utvrđivanje magnetskih svojstava materijala. Unapređenje konstrukcije je izvr&scaron;eno kroz vi&scaron;e iteracija i prototipova. Merenje vrednosti ukupnog kočnog momenta je podeljeno na merenje vi&scaron;e njegovih komponenti pri različitim vrednostima broja obrtaja i upravljačke struje namotaja.</p> / <p>In this thesis magnetorheological disk brake construction improvement is considered, with the goal to increase the overall braking torque value. For purposes of better understanding of material to magnetic field relationship, series of magnetic field testing were conducted. Construction improvement has been carried out through several iterations and different prototypes. Overall braking torque value measurements have been divided into several component measurements, utilizing different rotational speeds and coil control currents.</p>

In this study, various stability control systems are developed to remove the lateral instability of a conventional articulated steer vehicle (ASV) during the oscillatory yaw motion or “snaking mode”. First, to identify the nature of the instability, some analyses are performed using several simplified models. These investigations are mainly focused on analyzing the effects of forward speed and of two main subsystems of the vehicle, the steering system and tires, on the stability. The basic insights into the stability behavior of the vehicle obtained from the stability analyses of the simplified models are verified by conducting some simulations with a virtual prototype of the vehicle in ADAMS. To determine the most critical operating condition with regard to the lateral stability and to identify the effects of vehicle parameters on the stability, various studies are performed by introducing some modifications to the simplified models. Based on these studies, the disturbed straight-line on-highway motion with constant forward speed is recognized as the most critical driving condition. Also, the examinations show that when the vehicle is traveling with differentials locked, the vehicle is less prone to the instability. The examinations show that when the vehicle is carrying a rear-mounted load having interaction with ground, the instability may happen if the vehicle moves on a relatively good off-road surface. Again, the results gained from the analyses related to the effects of the vehicle parameters and operating conditions on the stability are verified using simulations in ADAMS by making some changes in the virtual prototype for any case. To stabilize the vehicle during its most critical driving condition, some studies are directed to indicate the shortcomings of passive methods. Alternative solutions, including design of different types of stability control systems, are proposed to generate a stabilizing yaw moment. The proposed solutions include an active steering system with a classical controller, an active torque vectoring device with a robust full state feedback controller, and a differential braking system with a robust variable structure controller. The robust controllers are designed by using simplified models, which are also used to evaluate the ability to deal with the uncertainties of the vehicle parameters and its variable operating conditions. These controllers are also incorporated into the virtual prototype, and their capabilities to stabilize the vehicle in different operating conditions and while traveling on different surfaces during the snaking mode are shown.

In this study, various stability control systems are developed to remove the lateral instability of a conventional articulated steer vehicle (ASV) during the oscillatory yaw motion or “snaking mode”. First, to identify the nature of the instability, some analyses are performed using several simplified models. These investigations are mainly focused on analyzing the effects of forward speed and of two main subsystems of the vehicle, the steering system and tires, on the stability. The basic insights into the stability behavior of the vehicle obtained from the stability analyses of the simplified models are verified by conducting some simulations with a virtual prototype of the vehicle in ADAMS. To determine the most critical operating condition with regard to the lateral stability and to identify the effects of vehicle parameters on the stability, various studies are performed by introducing some modifications to the simplified models. Based on these studies, the disturbed straight-line on-highway motion with constant forward speed is recognized as the most critical driving condition. Also, the examinations show that when the vehicle is traveling with differentials locked, the vehicle is less prone to the instability. The examinations show that when the vehicle is carrying a rear-mounted load having interaction with ground, the instability may happen if the vehicle moves on a relatively good off-road surface. Again, the results gained from the analyses related to the effects of the vehicle parameters and operating conditions on the stability are verified using simulations in ADAMS by making some changes in the virtual prototype for any case. To stabilize the vehicle during its most critical driving condition, some studies are directed to indicate the shortcomings of passive methods. Alternative solutions, including design of different types of stability control systems, are proposed to generate a stabilizing yaw moment. The proposed solutions include an active steering system with a classical controller, an active torque vectoring device with a robust full state feedback controller, and a differential braking system with a robust variable structure controller. The robust controllers are designed by using simplified models, which are also used to evaluate the ability to deal with the uncertainties of the vehicle parameters and its variable operating conditions. These controllers are also incorporated into the virtual prototype, and their capabilities to stabilize the vehicle in different operating conditions and while traveling on different surfaces during the snaking mode are shown.

Active safety systems for road vehicles have been improved considerably in recent years along with technological advances and the increasing demand for road safety. In the development route of active safety systems which started with introduction of digital controlled ABS in the late seventies, vehicle stability control systems have been developed which today, with an integration approach, incorporate ABS and other previously developed active safety technologies. ABS, as a main part of this new structure, still maintains its importance. In this thesis, a design methodology of an antilock braking system controller for four wheeled road vehicles is presented with a detailed simulation work. In the study, it is intended to follow a flexible approach for integration with unified control structure of an integrated active safety system. The objective of the ABS controller, as in the previous designs in literature, is basically to provide retention of vehicle directional control capability and if possible shorter braking distances by controlling the wheel slip during braking. iv A hierarchical structure was adopted for the ABS controller design. A high-level controller, through vehicle longitudinal acceleration based estimation, determines reference slip values and a low-level controller attempts to track these reference slip signals by modulating braking torques. Two control alternatives were offered for the design of the low-level controller: Fuzzy Logic Control and PID Control. Performance of the ABS controller was analyzed through extensive simulations conducted in MATLAB/Simulink for different road conditions and steering maneuvers. For simulations, an 8 DOF vehicle model was constructed with nonlinear tires.

Durch das I-FAS der TU Chemnitz wurde im Rahmen des AKTIV-Projektes eine Probandenstudie zur Akzeptanz von Systemausprägungen einer Aktiven Gefahrenbremsung (AGB) bei PKW durchgeführt. Unter Verwendung eines stehenden Hindernisses wurden sechs Systemausprägungen verglichen, die von den AGB-Partnern in zwei Versuchsträger implementiert wurden. Die sechs Systemausprägungen werden nahezu identisch bewertet, solange Probanden keine Vergleichsmöglichkeit zu anderen Systemausprägungen haben. Wenn es zu einem Fahrereingriff kommt, ist der Eingriffszeitpunkt des Fahrers unabhängig von der gefahrenen Systemausprägung.

Submitted by GUSTAVO DE ANDRADE SILVA (obscuremetaller@gmail.com) on 2018-10-09T01:43:22Z No. of bitstreams: 1 Dissertacao Mestrado - Gustavo de Andrade SIlva.pdf: 6925468 bytes, checksum: 967cb2ee2e821188542fb5b1fb5af49f (MD5) / Rejected by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br), reason: Solicitamos que realize uma nova submissão seguindo as orientações abaixo: 1 - Inserir no corpo do texto a ficha catalográfica, pois é um ítem obrigatório. 2 - Inserir no corpo do texto a cópia da ata de defesa, pois é um ítem obrigatório. Agradecemos a compreensão. on 2018-10-09T12:05:19Z (GMT) / Submitted by GUSTAVO DE ANDRADE SILVA (obscuremetaller@gmail.com) on 2018-10-09T15:27:51Z No. of bitstreams: 1 Dissertacao Mestrado - Gustavo de Andrade SIlva.pdf: 7092505 bytes, checksum: 841cdeae95494c0f93e55115aa751924 (MD5) / Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2018-10-09T16:59:44Z (GMT) No. of bitstreams: 1 silva_ga_me_bauru.pdf: 7092505 bytes, checksum: 841cdeae95494c0f93e55115aa751924 (MD5) / Made available in DSpace on 2018-10-09T16:59:44Z (GMT). No. of bitstreams: 1 silva_ga_me_bauru.pdf: 7092505 bytes, checksum: 841cdeae95494c0f93e55115aa751924 (MD5) Previous issue date: 2018-08-30 / O relógio inteligente é um novo tipo de eletrônico para o punho com funcionalidades idênticas as de um celular, que também é utilizado por motoristas durante a tarefa de condução do veículo, representando uma nova forma de distração do motorista, e risco aumentado de acidentes no trânsito; uma demanda da ergonomia cognitiva. O objetivo do presente estudo foi determinar o efeito do uso de relógio inteligente sobre motoristas experientes e novatos durante a condução simulada de automóvel, na tarefa de seguir o automóvel à frente, através da análise de movimento dos olhos, da cabeça e do desempenho na condução. Vinte motoristas experientes (EXP) e vinte motoristas novatos (NOV) realizaram a tarefa de seguir um carro à frente por um percurso de 2 km em quatro condições: somente seguir o carro (CAR), seguir o carro e receber uma notificação de texto no relógio inteligente (NOT), seguir o carro que freará de modo inesperado e brusco (FRE) e seguir o carro que freará de modo inesperado e brusco e, adicionalmente, receber uma notificação de texto (FNOT). Os dados do olhar, da cabeça e do desempenho na condução do automóvel foram submetidos à análise de variância de grupo (EXP, NOV) por condição de freada (CAR, FRE) por condição de notificação (NOT, FNOT) por tentativa (1, 2, 3). O desempenho da condução de veículo foi afetado pela freada do carro à frente e pelo uso do relógio inteligente ao receber notificação. Ao receber uma notificação no relógio, mudava-se o foco atencional do trânsito para realizar a leitura de texto, aumentando as chances de ocorrência de acidente. Experientes e novatos apresentaram diferentes estratégias para viabilizar a leitura do texto no relógio; experientes mostraram-se mais eficientes, mas ambos grupos desviaram o olhar da pista em detrimento da atenção, o que resultou em condição de risco. / Smartwatch is a new kind of electronic to be worn on the wrist with features similar to those of mobile phones, they are also being used by drivers during their driving task, representing a new form of distraction for drivers and increasing chances of traffic accidents. The goal of this project is to determine the use effect of smartwatches on experienced and novice drivers while driving on a simulated driving task following a vehicle ahead, through the analysis of eye and head movement and driving performance in a driving simulator. Twenty experienced drivers (EXP) and twenty novice drivers (NOV) will follow a car ahead for 2 kilometers in four conditions: follow a car ahead (CAR), follow a car ahead and receive a text message notification on the smartwatch (NOT), follow a car ahead that brakes abruptly (FRE) and follow a car ahead and receive a text message notification on the smartwatch while the car ahead brakes abruptly (FNOT). The gaze, head movement and driving performance data will be subjected to group variance analysis (EXP, NOV), with or without braking (CAR, FRE), with or without smartwatch notification (NOT, FNOT) and by trial (1, 2, 3). The diver’s performance showed to be affected by the car’s ahead braking and by the use of smartwatch during reading tasks. Attentional focus was shifted away from the road to the smartwatch when drivers tried to perform the reading task, thus increasing the chances of an accident. Experienced and novice drivers used different strategies to perform the reading task while driving; experienced drivers were more efficient but both groups shifted their gaze away from the road in detriment of their attention to the traffic, which resulted in risk conditions.

This Master´s thesis deals with construction design of break system of the tractor Zetor Forterra HSX. At the beginning, there is an overview of different possibilities breaking system from other world´s producers of tractors. Afterwards there is constructional working from selection variant of suspension to final project. In this case the thesis contains required calculations of the whole device. Thesis also contains the stress and strain analysis of selected components of construction using a numerical approach of finite element method and drawing documentation of the selected components.