A capacidade de simulação nos atributos de dinâmica veicular tem crescido nos últimos anos, especialmente para os atributos de handling (manobrabilidade e estabilidade) e steering (dirigibilidade). Entretanto, as simulações de ride (em especial dos fenômenos de ride secundário) continuam muito dependentes de modelos sofisticados de pneus. Tais modelos devem ser capazes de simular fenômenos de freqüência mais alta tais como impacto e transmissibilidade de aspereza em três direções. Este trabalho apresenta uma abordagem semi-analítica para o problema de simulação de fenômenos de ride, através do uso de dados de medição em pista gerados através de transdutores de força (wheel force transducers, WFTs). Tais transdutores são tipicamente usados para fins de cascateamento de cargas e durabilidade. Através do uso de tais carregamentos, é possível simular fenômenos de ride em toda a faixa de frequência de estudo (até 8 Hz para ride primário e até 100 Hz para ride secundário) sem a necessidade de um modelo específico de pneu. Usando um modelo de veículo completo construído no software ADAMS, são apresentados dados de correlação com o veículo real e um estudo de caso através da alteração de propriedades de elementos tais como amortecedores, coxins e buchas de suspensão. / Vehicle dynamics CAE capabilities has increased in the past few years, specially, for handling and steering attributes. However, secondary ride simulations are still highly depended on the tire model. Such tire model must be capable to simulate high order phenomenon such as impact and harshness transmissibility in three directions. This dissertation presents a semi-analytical approach to the ride phenomena simulation problem, using data gathered via wheel force transducers (WFTs) that are typically used for load cascading and durability purposes. Using such load histories, it becomes possible to simulate ride phenomena through the whole typical ride frequency range (up to 8 Hz for primary ride and up to 100 Hz for secondary ride) without the necessity of using a special tire model. The results obtained from this approach using a complete car model developed using ADAMS software showed a very good correlation between measured data and simulations. Then on this work a case study using different properties for components such as shock abosrbers, engine mounts and suspension bushings is conducted in order to show the method\'s potential for ride optimization.

A capacidade de simulação nos atributos de dinâmica veicular tem crescido nos últimos anos, especialmente para os atributos de handling (manobrabilidade e estabilidade) e steering (dirigibilidade). Entretanto, as simulações de ride (em especial dos fenômenos de ride secundário) continuam muito dependentes de modelos sofisticados de pneus. Tais modelos devem ser capazes de simular fenômenos de freqüência mais alta tais como impacto e transmissibilidade de aspereza em três direções. Este trabalho apresenta uma abordagem semi-analítica para o problema de simulação de fenômenos de ride, através do uso de dados de medição em pista gerados através de transdutores de força (wheel force transducers, WFTs). Tais transdutores são tipicamente usados para fins de cascateamento de cargas e durabilidade. Através do uso de tais carregamentos, é possível simular fenômenos de ride em toda a faixa de frequência de estudo (até 8 Hz para ride primário e até 100 Hz para ride secundário) sem a necessidade de um modelo específico de pneu. Usando um modelo de veículo completo construído no software ADAMS, são apresentados dados de correlação com o veículo real e um estudo de caso através da alteração de propriedades de elementos tais como amortecedores, coxins e buchas de suspensão. / Vehicle dynamics CAE capabilities has increased in the past few years, specially, for handling and steering attributes. However, secondary ride simulations are still highly depended on the tire model. Such tire model must be capable to simulate high order phenomenon such as impact and harshness transmissibility in three directions. This dissertation presents a semi-analytical approach to the ride phenomena simulation problem, using data gathered via wheel force transducers (WFTs) that are typically used for load cascading and durability purposes. Using such load histories, it becomes possible to simulate ride phenomena through the whole typical ride frequency range (up to 8 Hz for primary ride and up to 100 Hz for secondary ride) without the necessity of using a special tire model. The results obtained from this approach using a complete car model developed using ADAMS software showed a very good correlation between measured data and simulations. Then on this work a case study using different properties for components such as shock abosrbers, engine mounts and suspension bushings is conducted in order to show the method\'s potential for ride optimization.

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Frame and cab suspension designs of Class 8 heavy trucks were investigated to see their effects on ride comfort. Four trucks were used in this study, each with a different frame: a factory low frame, a lightweight low frame, a factory high frame, and a lightweight high frame. There were two different frame heights and three thicknesses. Two different rear cab suspensions were also tried out on each truck. Both suspensions used two airsprings and two dampers mounted vertically to control the vertical motion. The first suspension used two horizontally mounted dampers to control the lateral motion, while the second used a panhard rod connected to a torsion spring. In addition, two different sets of airsprings and two sets of vertical shocks were tried with each suspension, giving eight suspension combinations. The trucks were shaken through the forward drive (second) axle using two 5500 lb hydraulic actuators with displacement control. The steering (first) axle was left in contact with the ground (through the tires) and the rear drive (third) axle was strapped to the truck's frame and acted solely as dead weight. The actuators were given various inputs including single frequency sinusoidal signals, step signals, and decreasing amplitude chirp signals. Both roll and heave modes of the truck were excited. The ride was measured using three accelerometers located at the B-post inside the truck cab. These accelerometers were oriented in the vertical, fore/aft (longitudinal), and lateral (left/right) directions. Numerous other accelerometers and LVDTs were used to measure frame and cab motion. This study found that there while the beaming frequency shifted downward with the lighter frames, there was only a small decrease in ride quality. The panhard suspension rod had significantly higher roll motion, but the heave amplitudes were similar to the lateral damper suspension. Switching vertical shocks had a significant effect on heave motion, but none on the cab's roll. Switching the airsprings on the cab suspension in this study had no effect. / Master of Science

Fully automated or autonomous vehicles (AVs) hold great promise for the future of transportation, with Google and other auto manufacturers intending on introducing self-driving cars to the public by 2020. New automation functionalities will produce dramatic transportation system changes, across safety, mobility, travel behavior, and the built environment. This work’s results indicate that AVs may save the U.S. economy up to $37.7 billion from safety, mobility and parking improvements at the 10% market penetration level (in terms of system-wide vehicle-miles traveled [VMT]), and up to $447.1 billion with 90% market penetration. With only 10% market share, over 1,000 lives could be saved annually. However, realizing these potential benefits while avoiding pitfalls requires overcoming significant barriers including AV costs, liability, security, privacy, and missing research. Additionally, once fully self-driving vehicles can safely and legally drive unoccupied, a new personal travel transportation mode looks set to arrive. This new mode is the shared automated vehicle (SAV), combining on-demand service features with self-driving capabilities. This work simulates a fleet of SAVs operating within Austin, Texas, first using an idealized grid-based representation, and next using Austin’s actual transportation network and travel demand flows. This second model incorporates dynamic ride-sharing (DRS), allowing two or more travelers with similar origins, destinations and departure times to share a ride. Model results indicate that each SAV could replace around 10 conventionally-owned household vehicles while serving over 56,000 person-trips. SAVs’ ability to relocate unoccupied between serving one traveler and the next may cause an increase of 7-10% more travel; however, DRS can result in reduced overall VMT, given enough SAV-using travelers willing to ride-share. Furthermore, using DRS results in overall lower wait and service times for travelers, particularly from pooling rides during peak demand. SAVs should produce favorable emissions outcomes, with an estimated 16% less energy use and 48% lower volatile organic compound (VOC) emissions, per person-trip compared to conventional vehicles. Finally, assuming SAVs cost $70,000 each, an SAV fleet in Austin could provide a 19% return on investment, when charging $1 per trip-mile served. In summary, this new paradigm holds much promise that technological advances may soon realized. / text

Denna studie är ämnad att utreda hur samåkningsföretag kan arbeta medvarumärkesprofilering för att stärka sitt varumärkeskapital. Detta har undersökts genom attstudera vilka faktorer som är viktiga för kunder vid valet att samåka med fokus på densvenska marknaden. Dessa undersökningar har baserat sig på intervjuer med företagenSkjutsgruppen och GoMore samt deras kunder. Studien visar att de viktigaste faktorerna förkunder vid valet att samåka på den svenska marknaden är ekonomiska incitament, miljö,trygghet och säkerhet, flexibilitet samt social interaktion. Av dessa är de ekonomiskaincitamenten viktigast för valet att samåka. Studien har sedan undersökt hursamåkningsföretag, baserat på dessa identifierade faktorer, kan arbeta med sinvarumärkesprofilering för att stärka företagets varumärkeskapital. Studien resulterar i en modell enligt vilken samåkningsföretag kan arbeta med sinvarumärkesprofilering för att stärka sitt varumärkeskapital. Modellen föreslår attsamåkningsföretagen skapar kännedom om varumärket genom marknadsföringsåtgärder somuppmärksammar kunderna på varumärket. Detta ökar varumärkets relevans, det vill sägavarumärket finns med i kundernas minne då de väljer tjänst. Marknadsföringen syftar ocksåtill att profilera företagets varumärke genom att förbättra kundernas inställning till varumärket.Målet med detta är att etablera en emotionell relation mellan kund och företag genom attfokusera på en faktor som lyfts fram som extra betydelsefull. Modellen föreslår också attföretagen samtidigt kan differentiera sig inom flera faktorer i att syfta att erbjuda en bättretjänst än konkurrenterna.

Shared ride systems match the travel demand of transport a client with the supply of vehicles, or hosts, so that the client find rides to their destinations. A peer-to-peer shared ride system allows a client to find rides in an ad-hoc manner, by negotiating directly with nearby hosts via radio-based communication. Such a peer-to-peer shared ride system has to deal with various types of hosts, such as private cars, taxicabs and mass transit vehicles. Agents, i.e. a client and hosts, have diverse behaviors in such systems. Their different behaviors affect the negotiation process, and consequently the travel choices. Preliminary research (Winter et al. 2005) has investigated peer-to-peer shared ride systems with homogeneous hosts and immobile client. This thesis extends their work to multiple types of agents. It focuses on what are typical agent behaviors in peer-to-peer shared ride systems, and how these behaviors affect negotiation processes in a dynamic transport environment. (For complete abstract open document)

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The diploma thesis, which belongs to the area of vehicle dynamics, deals with the issue of suspension of trucks cabins. In particular, it focuses on the suspension of a race truck cab such as the Rally Dakar. Includes an overview of truck suspension (especially cabs), driving comfort assessment methods and the impact of vibration on human. To verify the suitability of using different cab suspension concepts, a multibody model was built in program MSC ADAMS. Suitable primary suspension has been found appropriate for this model. Cab suspension was tested for driving safety, but first for driving comfort.

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