O objetivo da pesquisa aqui relatada é desenvolver um modelo de simulação estocástica capaz de reproduzir a circulação de trens em trechos de linha singela. O modelo é usado para avaliar o impacto que determinadas alterações podem provocar sobre o desempenho do sistema. Os fatores estudados são o número de estações existentes, os horários de partida dos trens, os tempos de parada nas estações e a velocidade média dos trens, que foram combinados em sete cenários diferentes. Os efeitos das alterações propostas são avaliados em termos do tempo total de percurso dos trens, o tempo médio de espera nas estações, a fila média, o tempo em que os trens ficam parados e circuIando, os tempos de ocupação dos desvios e a velocidade média dos trens. / The objective ofthis research isto develop a stochastic simulation model capable to reproduce the circulation of trains on a single track line. The proposed model is used to assess the impact of certain changes on the overall performance of the system. Seven different scenarios are used with this purpose. These scenarios include changes in the number of stations, train departure times, duration of stopping times at the stations and the train average speeds. The overall effect of these changes on the system is assessed by means of the trains total travel times, average waiting times at the stations, average queue lengths, running and stopping times, occupation times for sidings and the overall average speed for trains.

O objetivo da pesquisa aqui relatada é desenvolver um modelo de simulação estocástica capaz de reproduzir a circulação de trens em trechos de linha singela. O modelo é usado para avaliar o impacto que determinadas alterações podem provocar sobre o desempenho do sistema. Os fatores estudados são o número de estações existentes, os horários de partida dos trens, os tempos de parada nas estações e a velocidade média dos trens, que foram combinados em sete cenários diferentes. Os efeitos das alterações propostas são avaliados em termos do tempo total de percurso dos trens, o tempo médio de espera nas estações, a fila média, o tempo em que os trens ficam parados e circuIando, os tempos de ocupação dos desvios e a velocidade média dos trens. / The objective ofthis research isto develop a stochastic simulation model capable to reproduce the circulation of trains on a single track line. The proposed model is used to assess the impact of certain changes on the overall performance of the system. Seven different scenarios are used with this purpose. These scenarios include changes in the number of stations, train departure times, duration of stopping times at the stations and the train average speeds. The overall effect of these changes on the system is assessed by means of the trains total travel times, average waiting times at the stations, average queue lengths, running and stopping times, occupation times for sidings and the overall average speed for trains.

The purpose of this work is to investigate if simple vehicle models are realisticand useful in simulator environment. These simple models have been parametrisedby the Department of Electrical Engineering at Linköping University and havebeen validated with good results. The models have been implemented in a simulatorenvironment and a simulator study was made with 24 participants. Eachtest person drove both slalom and double lane change manoeuvres with the simplemodels and with VTI’s advanced model. The test persons were able to successfullycomplete double lane changes for higher velocities with the linear tyre modelcompared to both the non-linear tyre model and the advanced model. The wholestudy shows that aggressive driving of a simple vehicle model with non-linear tyredynamics is perceived to be quite similar to an advanced model. It is noted significantdifferences between the simple models and the advanced model when drivingunder normal circumstances, e.g. lack of motion cueing in the simple model suchas pitch and roll.

<p>Railway transportation is showing a substantial increase. Investments in new infrastructure, new fast and comfortable vehicles, and high frequency of service are important factors behind the increase.</p><p>Infrastructure configuration and timetable construction play important roles in the competitiveness of railway transportation. This is especially true on single-track lines where the travel times and other timetable related parameters are severely restricted by crossings (train meetings). The crossings also make the lines’ operation more sensitive to disturbances.</p><p>Since the major part of the Swedish railway network is single-track it is of great interest to examine the relationships between operation properties, such as travel times and reliability, and infrastructure configuration on single-track lines. The crossings are the core feature of single-track operation and this thesis focuses on the crossing time, i.e. the time loss that occurs in crossing situations.</p><p>A simplified analytical model, SAMFOST, has been developed to calculate the crossing time as a function of infrastructure configuration, vehicle properties, timetable and delays for two crossing trains. The effect of possible surrounding trains is not taken into account and all kinds of congestion effects are thus excluded from evaluation. SAMFOST has been successfully validated against the simulation tool RailSys, which shows that this type of simplified model is accurate in non-congested situations.</p><p>A great advantage of disregarding congested situations is that analysis is independent of timetable assumptions. The model also explicitly shows the effect of punctuality, which is of particular importance on single-track lines where the interdependencies between trains are strengthened by the crossings.</p><p>For the same reason, the timetable is severely constrained. Nonetheless, there is often a need for changes of the timetable (crossing pattern). The thesis proposes three simple measures of timetable flexibility, all based on assigned crossing time requirements. Together, these measures can be used to evaluate how infrastructure configuration, vehicle properties, punctuality etc affect possibilities to alter the timetable.</p><p>As an example of its application, SAMFOST has been used to evaluate the effect of shorter inter-station distance, partial double-track and combined crossing and passenger stop. These measures affect the operational properties quite differently.</p><p>More crossing stations result in a minor decrease in travel time (lower mean crossing time) but significantly higher reliability (lower crossing time variance). These effects are independent of punctuality, which is a valuable property.</p><p>A partial double-track results in shorter travel times and in some cases also higher reliability. Both effects are strongly dependent on punctuality and high punctuality is needed to achieve high effects.</p><p>A combined crossing and passenger stop results in a situation similar to that of a partial double-track. In this case it is important to point out that the assignment of time supplements in the timetable should be directly correlated to punctuality in order to achieve good operation.</p>

<p>This work is concerned with the dynamics and stability of nonlinear systems that roll in a single track, including holonomic and nonholonomic systems. First the classic case of Euler's disk is introduced as an example of a nonholnomic system in three dimensions, and the methodology for deriving equations of motion that is used throughout this work is demonstrated, including use of Lagrange's equations, accommodating constraints with both Lagrange multipliers and with Gauss's Principle. </p><p>Next, a disk in two dimensions with an eccentric center of mass is explored. The disk is assumed to roll on a cubic curve, creating the possibility of well-escape behavior, which is examined analytically and numerically, showing regions of multi-periodicity and chaos. This theoretical system is compared to an experiment designed</p><p>to demonstrate the same behavior.</p><p>The remainder of the present document is concerned with the stability of a bicycle, both on flat ground, and on a type of trainer known as "rollers." The equations of motion are derived using Lagrange's equations with nonholonomic constraints, then the equations are linearized about a constant forward velocity, and a straight path, yielding a two degree of freedom system for the roll and steer angles. Stability is then determined for a variety of different parameters, exploring the roll of bicycle geometry and rider position, along with the effect of adding a steering torque, taking the form of different control laws.</p><p>Finally, the system is adapted to that of a bicycle on rollers, and the related equations of motion are derived and linearized. Notable differences with the classic bicycle case are detailed, a new eigenvalue behavior is presented, and configurations for optimal drum spacing are recommended.</p> / Dissertation

Unstable legged robots fall over without active stabilization, typically by repositioning the feet to maintain/regain stability of balance. This dissertation concerns the development of a Single-Track Three Legged Mobile Robot (ST3LMR) and control system. A proof-of-concept was demonstrated through digital simulation and experimentation with physical prototypes. The ST3LMR comprises a body and three articulated legs arranged in a narrow profile, one behind the other, to walk and maneuver along narrow trails and paths. The ST3LMR walks by placing successive footfalls in a generally single-track or in-line fashion. It achieves the form and function of a motorcycle but with the added benefit of legs and robotic control. That is, the feet are stationary with respect to footholds during the support period, thus eliminating the drawback of wheels, which require continuous support (especially when used in rugged terrain). By always having at least two feet on the ground, the ST3LMR is inherently stable in the pitch axis (in the forward/backward direction of motion), which allows for decoupling stability of balance control to only the roll axis (in the left/right direction).Suggested by recent developments in high-performance computing, walking robot locomotion and stabilization is considered from a new perspective, that of the Monte Carlo (MC) method. A high-speed MC simulation is used in a model-predictive control system to determine footholds that provide stability of balance. Stability of balance, maneuverability, and control is demonstrated through experimental results from physical prototypes and a simple digital simulation of an impulse response, avoidance maneuver, and leaning-into-the-turn maneuver.

Mapping stationary objects and tracking moving targets are essential for many autonomous functions in vehicles. In order to compute the map and track estimates, sensor measurements from radar, laser and camera are used together with the standard proprioceptive sensors present in a car. By fusing information from different types of sensors, the accuracy and robustness of the estimates can be increased. Different types of maps are discussed and compared in the thesis. In particular, road maps make use of the fact that roads are highly structured, which allows relatively simple and powerful models to be employed. It is shown how the information of the lane markings, obtained by a front looking camera, can be fused with inertial measurement of the vehicle motion and radar measurements of vehicles ahead to compute a more accurate and robust road geometry estimate. Further, it is shown how radar measurements of stationary targets can be used to estimate the road edges, modeled as polynomials and tracked as extended targets. Recent advances in the field of multiple target tracking lead to the use of finite set statistics (FISST) in a set theoretic approach, where the targets and the measurements are treated as random finite sets (RFS). The first order moment of a RFS is called probability hypothesis density (PHD), and it is propagated in time with a PHD filter. In this thesis, the PHD filter is applied to radar data for constructing a parsimonious representation of the map of the stationary objects around the vehicle. Two original contributions, which exploit the inherent structure in the map, are proposed. A data clustering algorithm is suggested to structure the description of the prior and considerably improving the update in the PHD filter. Improvements in the merging step further simplify the map representation. When it comes to tracking moving targets, the focus of this thesis is on extended targets, i.e., targets which potentially may give rise to more than one measurement per time step. An implementation of the PHD filter, which was proposed to handle data obtained from extended targets, is presented. An approximation is proposed in order to limit the number of hypotheses. Further, a framework to track the size and shape of a target is introduced. The method is based on measurement generating points on the surface of the target, which are modeled by an RFS. Finally, an efficient and novel Bayesian method is proposed for approximating the tire radii of a vehicle based on particle filters and the marginalization concept. This is done under the assumption that a change in the tire radius is caused by a change in tire pressure, thus obtaining an indirect tire pressure monitoring system. The approaches presented in this thesis have all been evaluated on real data from both freeways and rural roads in Sweden. / SEFS -- IVSS / VR - ETT

This thesis deals with simulation vehicle models for lateral control. It surveys step by step to models of tire, truck and control. At the end are showed influences of model parameters to vehicles dynamics.

Railway transportation is showing a substantial increase. Investments in new infrastructure, new fast and comfortable vehicles, and high frequency of service are important factors behind the increase. Infrastructure configuration and timetable construction play important roles in the competitiveness of railway transportation. This is especially true on single-track lines where the travel times and other timetable related parameters are severely restricted by crossings (train meetings). The crossings also make the lines’ operation more sensitive to disturbances. Since the major part of the Swedish railway network is single-track it is of great interest to examine the relationships between operation properties, such as travel times and reliability, and infrastructure configuration on single-track lines. The crossings are the core feature of single-track operation and this thesis focuses on the crossing time, i.e. the time loss that occurs in crossing situations. A simplified analytical model, SAMFOST, has been developed to calculate the crossing time as a function of infrastructure configuration, vehicle properties, timetable and delays for two crossing trains. The effect of possible surrounding trains is not taken into account and all kinds of congestion effects are thus excluded from evaluation. SAMFOST has been successfully validated against the simulation tool RailSys, which shows that this type of simplified model is accurate in non-congested situations. A great advantage of disregarding congested situations is that analysis is independent of timetable assumptions. The model also explicitly shows the effect of punctuality, which is of particular importance on single-track lines where the interdependencies between trains are strengthened by the crossings. For the same reason, the timetable is severely constrained. Nonetheless, there is often a need for changes of the timetable (crossing pattern). The thesis proposes three simple measures of timetable flexibility, all based on assigned crossing time requirements. Together, these measures can be used to evaluate how infrastructure configuration, vehicle properties, punctuality etc affect possibilities to alter the timetable. As an example of its application, SAMFOST has been used to evaluate the effect of shorter inter-station distance, partial double-track and combined crossing and passenger stop. These measures affect the operational properties quite differently. More crossing stations result in a minor decrease in travel time (lower mean crossing time) but significantly higher reliability (lower crossing time variance). These effects are independent of punctuality, which is a valuable property. A partial double-track results in shorter travel times and in some cases also higher reliability. Both effects are strongly dependent on punctuality and high punctuality is needed to achieve high effects. A combined crossing and passenger stop results in a situation similar to that of a partial double-track. In this case it is important to point out that the assignment of time supplements in the timetable should be directly correlated to punctuality in order to achieve good operation. / <p>QC 20170222</p>

O expressivo crescimento do setor ferroviário com o processo de privatizações das operações a partir de 1996, fez com que a modalidade aumentasse sua participação na matriz de transportes brasileira. Porém, essa expansão, obtida essencialmente com a substituição e aumento de locomotivas e vagões, juntamente com a modernização do sistema de controle de tráfego, deverá em breve encontrar limites impostos pela geometria e superestrutura da malha ferroviária. O objetivo da dissertação é analisar como esses fatores afetam a capacidade de processamento de trens através de uma linha ferroviária singela. Para alcançar este objetivo desenvolveu-se um modelo capaz de identificar as características da via que restringem as velocidades e o headway das composições ferroviárias. O modelo proposto permite, através da análise de desempenho em cada um dos arcos de um trecho de linha ferroviária, obter uma medida de desempenho global no trecho e identificar os gargalos. O método adotado para determinar a capacidade do trecho para cenários operacionais alternativos é o da utilização de diagramas espaço-tempo. Os diagramas espaço-tempo são elaborados através de um algoritmo em MatLab que soluciona os conflitos nos cruzamentos para um determinado tempo de cruzamento nas estações e efetua a contagem de pares de trens. O desempenho dos trens em cada um dos arcos, dado de entrada do algoritmo, é adquirido através de um modelo de simulação de desempenho de trens elaborado pela Association of Amerian Railroads (AAR). Como aplicação prática apresenta-se uma análise de capacidade para um dos principais corredores de exportação, um trecho da Brasil Ferrovias S.A. entre as cidades de Santa Fé do Sul e Araraquara no estado de São Paulo. A análise dos resultados mostra que o principal fator limitante da velocidade média no espaço dos trens é a atual condição da superestrutura ferroviária e que, uma vez eliminada esta restrição, a supressão de passagens de nível e a relocação de estações de cruzamento, produzem ganhos expressivos. / The expessive growth of the railway sector due to the privatization of the operations since 1996, is increasing the participation of this mode in the brazilian transport matrix. However, this growth is obtained mainly from the replacement and increase of the rolling stock and the modernization of the traffic control system, and will soon reach some important limits imposed by the railway geometry and superstructure. The thesis objective is to analyze how these factors affect the capacity to process trains through a single track railroad line. To reach this objective, a model that identifies the restrictions that impose limits to the speed and headways of the trains was developed. Through the performance analysis on each arc of a railway segment, the model obtains a global performance measure for the whole segment and identifies the bottlenecks. Time-space graphs are developed to determine the capacity of the segment for different operating scenarios. To build the space-time graphs, solve the conflicts at the crossings for a given time to cross and count the trains per day, an algorithm using the MathLab software was developed. The train performance on each arc is obtained through a simulation model developed by the Association of American Railroads (AAR). As a practical application, a capacity analysis of one of the most important export corridors is presented, a segment of the Brasil Ferrovias S.A. network between the cities of Santa Fé do Sul and Araraquara in the state of São Paulo. The analysis of the results shows that the present railway superstructure condition is the main train average space speed limiting factor and, once this restriction is eliminated, the supression of at grade crossings and the relocation of the crossing stations produce expressive gains.