<div>Indiana University–Purdue University Indianapolis student team Jaguar has been participating in the electric Formula SAE (FSAE) vehicle competitions in the past few years. There is an urgent need to develop a design tool for improving the performance of the vehicle. In this thesis, multibody dynamics (MBD) models have been developed which allow the student team to improve their vehicle design, while reducing the required time and actual testing costs. Although there were some studies about MBD analyses for vehicles in literature, a detailed modeling study of key parameters is still missing. Specifically, the effect of suspension system on the vehicle performance is not well studied. </div><div>The objective of the thesis is to develop an MBD based model to improve the FSAE vehicle’s performance. Based on the objective and knowledge gap, the following research tasks are proposed: (1) MBD modeling of current suspension systems; (2) Modification of suspension systems, and (3) Evaluation of performance of modified suspension systems. </div><div>The models for the front suspension system, rear suspension system, and full assembly are created, and a series of MBD analyses are conducted. The parameters of the vehicle by conducting virtual tests on the suspension model and overall vehicle model are studied. In this work, two main virtual tests are performed. First, parallel wheel travel test on suspension system, in which the individual suspension system is subject to equal force on both sides. The test helps understand the variation in stability parameters, such as camber angle, toe angle, motion ratio, and roll center location. Second, skid-pad test on full assembly of the vehicle. The test assists in understanding the vehicle’s behavior in constant radius cornering and the tire side slip angle variation, as it is one of the important parameters controlling alignment of the vehicle in this test.</div><div>Based on the vehicle’s dynamics knowledge obtained from the existing vehicle, a modified version of the FSAE vehicle is proposed, which can provide a better cornering performance with minimum upgrades and cost possible. Based on the results from the parallel wheel travel test and skid-pad test, the lateral load transfer method is used to control the vehicle slip, by making changes to the geometry of the vehicle and obtaining appropriate roll center height for both front and rear suspension system. The results show that the stiffness in front suspension system and rear suspension system are controlled by manipulating roll center height. This study has provided insightful understanding of the parameters and forces involved in suspension system and their variations in different events influencing vehicle stability. Moreover, the MBD approach developed in this work can be readily extended to other commercial vehicles and sports vehicles.</div><div><br></div>

The SherpaTT rover is prepared for further autonomous long distance traverses in terrain akin to the Martian environment. However, it features a fueled power generator which cannot be employed in extra-terrestial scenarios. As the rover is meant to approach a higher technology readiness level, a photovoltaic power subsystem is proposed to guide future design iterations. This thesis presents the solar array sizing, design, and integration processes considered for two Martian mission sites: Iani Chaos at 2°S and Ismenius Cavus at 34°N. An alternative use case for the active suspension system is presented so that the proposed solar arrays may be inclined and oriented into power generating configurations that are more favorable than those achieved with passive suspension rovers. This results in traverse gains of up to 34% and 25% for clear days at Iani Chaos and Ismenius Cavus, respectively.

No description available.

Este trabalho aborda a aplicação de uma máquina elétrica síncrona do tipo tubular linear de ímãs permanentes em um sistema de suspensão semiativa. O uso de amortecedores eletromagnéticos lineares em sistemas de suspensão não é uma ideia nova, mas a maioria dos trabalhos publicados sobre este assunto concebem soluções ativas e negligenciam as semiativas, sobretudo com estudos experimentais. Nesta pesquisa é discutido um modelo dinâmico eletromecânico acoplado de um sistema de suspensão semiativa, considerando um amortecedor eletromagnético linear e também apresentando dados experimentais. Leis da mecânica clássica e do eletromagnetismo são aplicadas para descrever o sistema que combina teoria de vibrações e máquinas elétricas. Um modelo virtual com vários subsistemas foi implementado no ambiente MATLABR /Simulink/Simscape para associar equações e simular o desempenho global. Para o caso passivo, os resultados numéricos e experimentais validam os parâmetros e confirmam a funcionalidade do sistema e a metodologia proposta. Simulações e testes experimentais para o caso semiativo são consistentes, mostrando uma melhoria na transmissibilidade de deslocamento, em relação ao modo passivo, e a possibilidade de regeneração de energia. / This work addresses the application of a tubular linear permanent magnet synchronous machine working as a damper for a semi-active suspension system. The use of linear electromagnetic dampers in suspension systems is not a new idea. However, most published papers on this subject outline active solutions and neglect semi-active ones, above all, with experimental studies. Here a dynamic mechanicalelectromagnetic coupled model for a semi-active suspension system is reported. This is in conjunction with a linear electromagnetic damper and also presents experimental data. Classical laws of mechanics and electromagnetics are applied to describe a dynamic model combining vibration and electrical machines theories. A multifaceted MATLABR /Simulink/Simscape model was implemented to incorporate equations and simulate global performance. For the passive case, numerical and experimental results validate the parameters and confirm system function and the proposed methodology. Simulation and practical results for the semi-active case are consistent, showing an improvement in the displacement transmissibility and the possibility of energy regeneration.

The thesis deals with design of a semiactive seat suspension system for an agriculture machines and design of dynamic model of the system, which includes real parameters of a magnetorheological (MR) damper. The dynamic model is a single degree of freedom model and it is made in program Matlab. In the model, response time of the MR damper and three control algorithms are implemented (two-state Skyhook, Skyhook linear approximation damper control and Acceleration Driven Damper control). Based on the results of the simulations, the damping characteristics are defined, and the MR damper is modified to achieve fast response time. A test seat is designed to test transmission of vibrations to the driver. The simulation results provide a comparison of efficiency of the seat suspension depending on the response time and control algorithm, as well as a comparison with a passive suspension system. On the designed test seat with MR damper with a fast response time, the vibration transmission is reduced up to 25 % compared with the best passive seat suspension setup.

The push for sustainability in all parts of our society has never been as big as it is currently. One project that aims to produce sustainable innovation in the railway industry is the Delsbo Electric competition where some of the world’s most energy efficient vehicles compete. A dominant design has arisen in the competition which means that competitors must seek innovative avenues of development in order to find an edge over the competition. One such avenue has been to use composite material in construction to decrease mass and therefore increase energy efficiency. The KTH Delsbo Electric team views the suspension system as one such avenue that has the potential to improve efficiency. This project is a study into the dynamics of rail vehicles and especially rail vehicle suspension systems. Using a vehicle modelled in an MBS software a parametric study is conducted with the goal to optimize the energy efficiency through an iterating process by only varying the stiffness and damping parameters for the suspension system. Through the iterating process, it became clear that some parameters are more closely linked to different parts of the vehicle behavior than others. The energy efficiency is closely linked to the stiffness in the suspension, especially in the longitudinal direction. The ride comfort was found to be very much linked to the damping parameters. This made it possible to tune the stiffness and achieve high energy efficiency and then adapt that setup to gain better ride comfort. This study also concludes that the vehicle derailment factor (L/V) is inversely linked to energy efficiency. Therefore, an energy efficient vehicle is less likely to derail. The result of this thesis is a setup of energy efficient parameters that will lay the groundwork for a project to design and manufacture a suspension system with the outlined parameters. / Strävan efter hållbarhet i alla delar av vårt samhälle har aldrig varit så stor som den är idag. Ett sådant projekt, vars syfte är att producera hållbara innovationer inom järnvägsindustrin, är Delsbo Electric-tävlingen där några av världens mest energieffektiva fordon tävlar. En dominant design har uppstått vilket betyder att konkurrenter måste hitta innovativa utvecklingsriktningar för att skapa sig ett försprång gentemot de andra. En sådan riktning har varit användningen av kompositmaterial som minskar vikt och därmed ökar energieffektiviteten. KTH Delsbo Electric-teamet ser fjäder- och dämparsystemet som en riktning med hög potential att förbättra energieffektiviteten. Detta projekt är en studie inom spårfordonsdynamik och mer specifikt inom spårfordons fjäder- och dämparsystem. Genom användningen av ett fordon modellerat i ett MBS-program utförs en parameterstudie med målet att optimera energieffektiviteten genom en iterativ process där enbart styvheten och dämpningen varieras. Under den iterativa processen blev det uppenbart att olika parametrar har större påverkan på vissa fordons beteenden än andra. Energieffektiviteten är beroende av styvheten, speciellt i den longitudinella riktningen. Åkkomforten var mycket beroende av dämpningen. På grund av detta kunde styvheten ställas in för att optimera energieffektiviteten och sedan anpassa dämpningen så att åkkomforten blev acceptabel. Denna studie kom också fram till att urspårningsfaktorn (L/V) är omvänt länkad till energieffektiviteten hos ett fordon. Ett fordon som har hög energieffektivitet har därför mindre risk för urspårning. Resultatet av denna studie är en uppsättning energieffektiva parametrar som ska lägga grunden för framtida projekt att designa och tillverka ett fjäder- och dämparsystem utifrån dessa parametrar.

The Speed-Track is a prototype of tracked vehicle made for material transportation on yards andgalleries. It was realized in 2011 and during the past two years has been employed mainly forload transportation on mountains. The main innovations adopted by the vehicle are about thesuspension system and the hydrostatic transmission; the combination of both allows acomfortable driving up to a maximum speed of 20 km/h.First of all, the present thesis aims to quantitatively evaluate the performances of the vehiclefrom the point of view of the suspension system and the transmission. The design of the vehicle,in fact, has been driven by the designer’s experience and no preliminary simulations and sizingcomputations have been performed.According to the outcomes of the first step as well as the feedback, some improvements to thecurrent configuration are designed and evaluated. The feedback has been submitted to theprototype’s users through a questionnaire. Improvements are supposed to be easily implementedon the existing vehicle.The outcomes of the previous steps as well as the communication with employees andentrepreneurs and the knowledge of the state of the art in terms of construction and earthmovingmachines drive the last step of the present work.The employees and entrepreneurs consulted mainly work in the agricultural sector and they havebeen contacted through web-based forums. In addition, the participation to the fair Bauma 2013allowed us to get a more complete picture of the state of the art.New solutions, starting from scratch, are designed in the last part.Keywords: / Speed-Track är en prototyp av en spårfarkost utvecklad för materialtransport på gårdar och igallerior. Den konstruerades 2011 och under de senaste två åren har den främst använts för tungatransporter på berg.De huvudsakliga innovationerna av vilka farkosten använder sig av är kopplade tillsuspensionssystemet och den hydrostatiska transmissionen; kombinationen av dessa möjliggören bekväm resa i hastigheter upp till 20 km/h.Målet med detta examensarbete är framför allt att utvärdera prestandan hos farkosten medhänsyn till suspensionssystemet och transmissionen. Designen av farkosten har utformats baseratpå utvecklarens erfarenheter och inga preliminära simuleringar eller beräkningar har utförts.Baserat på resultaten från, och utvärdering av det första steget har vissa förbättringar till denrådande uppbyggnaden framtagits och utvärderats. Utvärderingen har lämnats till användare avprototypen genom ett frågeformulär.Förbättringarna skall vara lätta att tillämpa på den existerande farkosten.Resultaten från de föregående stegen tillsammans med en dialog med anställda och entreprenörersamt teknisk kunskap med avseende på konstruktion och jordfraktande maskiner driva det sistasteget av det presenterade arbetet.Medarbetare och entreprenörer härstammar framför allt från arbete inom jordbrukssektorn ochhar blivit kontaktade genom web-forum.Dessutom har medverkan under mässan Bauma 2013 givit en mer komplett bild av den rådandetekniken.Nya lösningar skapade från början utvecklas i arbetets sista del.

Med den kontinuerliga automationen och de globala mål som syftar till miljövänliga och grönare samhälle, bildades företaget TerraGo Deliveries med syfte att minimera växthusgasersutsläpp i stora städer genom hållbarare logistik. Deras mål är att bygga en robot som levererar mat från restauranger till kunder. Roboten ska gå på gångställe med människor för att minska trafiken i körfälten. Vanligtvis, går leveransen genom chaufförer som kör bilar eller moped som orsakar mer gasutsläpp och mer trängsel i trafik samt risk för olyckor. Det här projektet går ut med att framta ett upphängning system till första prototypen av TerraGo Deliveries robot som är sexhjuldriven. Det nya systemet ska klara sig med att gå på grusvägar och gå på trottoars kanter. För att komma fram till den slutliga designen så delas projektet in i flera olika delmoment som består av faktainsamling för upphängning system till olika fordon och robotar, skisser, mekanikberäkningar, CAD modellering, 3D-printing, värklighetstester, konceptutveckling och materialval. CAD-programmet Creo Parametric 5.0 har använts för att skapa 3D-modeller för de olika koncepten. Samt programmet Granta EduPack, som är ingenjörsmässigt materialdatabas, har varit ett verktyg för materialvalet. Dessutom renderingar på den slutliga designen har utförts med hjälp av KeyShot 10 för att visa hur den kommer se ut på verkligheten. Resultatet kommer att redovisa upphängningssystemet som en 3D-modell som visar hur den kommer att lösa problemet med hänsyn till montering anvisningar. Materialvalet för systemet hamnar på aluminiumlegeringen SS 4212–06. / With the continuous automation and the global goals that aim to more environmentally friendly and greener society, the company TerraGo Deliveries was formed with purpose of minimizing greenhouse gas emissions in large cities through more sustainable logistics. Their goal is to build a robot that delivers food from restaurants and shops to customers. The robot will go on the pavement at peoples’ speed to reduce traffic in the lanes. Usually, the delivery goes through drivers who drive cars or scooters that cause more gas emissions and more congestion in traffic as well as the risk of accidents. This project involves developing a suspension system for the first prototype of the TerraGo Deliveries robot, which is six-wheel drive. The new system will be able to go on gravel roads and climb on the curbs without any problem. To reach at the final design, the project has been divided into several different phases that consist of fact collection for suspension systems for different vehicles and robots, sketches, mechanical calculations, CAD-modeling, 3D-printing, reality tests, concept development and material selection. The CAD program Creo Parametric 5.0 has been used to create 3D models for the various concepts. And the program Granta EduPack, which is an engineering material database, has been a tool for material selection. In addition, renderings of the final design have been performed using KeyShot 10 to show how it will look like in reality. The result will present the suspension system as a 3D-model that shows how it will solve the problems, which are introduced in the report, with the assembly instructions. The choice of material for the system ends up on the aluminum alloy SS 4212–06.

Uma base elástica para ensaios seccionais de pontes foi projetada a partir de mancais aerostáticos. Um sistema de dois graus de liberdade foi construído, de forma a possibilitar estudos de flutter, de galloping e de vibrações induzidas por vórtices em túneis de vento. A base mostrou-se bastante versátil, permitindo diversas configurações além da inicialmente prevista, o que possibilita a realização de estudos envolvendo diferentes fenômenos aeroelásticos nos mais variados modelos. Foram realizados ensaios para a caracterização de galloping em um prisma de seção quadrada e de flutter em um fólio NACA 0020. Os resultados de galloping obtidos, considerando o escoamento incidente perpendicular a uma das faces do prisma, foram condizentes com os encontrados na literatura. Por outro lado, as derivadas de flutter obtidas nos ensaios com o fólio não foram aquelas esperadas. Ensaios complementares deverão ser realizados no futuro com o objetivo de determinar as fontes das discrepâncias observadas. / A new elastic suspension system using air bearings for heaving and pitching motions was designed to test section models of suspended bridges in wind tunnels. The two-degrees-of-freedom system and its versatility makes possible the study of many aeroelastic phenomena, such as galloping, vortex-induced vibrations, buffeting and flutter. Moreover, as a modular system is proposed, degrees of freedom can be easily removed or added as desired. Therefore, it can be used to study not only bridge aeroelasticity, but also fluid-structure interaction of other geometries. In order to verify the suspension system, galloping tests, using a square cylinder, and flutter tests, using a foil NACA 0020, were done at IPT\'s wind tunnel facility. The galloping response obtained for the square cylinder was consistent with the literature. On the other hand, the flutter derivatives obtained for the foil differ from those expected. Therefore, other investigations must be done in the future in order to identify the sources of the discrepancies observed.

Uma base elástica para ensaios seccionais de pontes foi projetada a partir de mancais aerostáticos. Um sistema de dois graus de liberdade foi construído, de forma a possibilitar estudos de flutter, de galloping e de vibrações induzidas por vórtices em túneis de vento. A base mostrou-se bastante versátil, permitindo diversas configurações além da inicialmente prevista, o que possibilita a realização de estudos envolvendo diferentes fenômenos aeroelásticos nos mais variados modelos. Foram realizados ensaios para a caracterização de galloping em um prisma de seção quadrada e de flutter em um fólio NACA 0020. Os resultados de galloping obtidos, considerando o escoamento incidente perpendicular a uma das faces do prisma, foram condizentes com os encontrados na literatura. Por outro lado, as derivadas de flutter obtidas nos ensaios com o fólio não foram aquelas esperadas. Ensaios complementares deverão ser realizados no futuro com o objetivo de determinar as fontes das discrepâncias observadas. / A new elastic suspension system using air bearings for heaving and pitching motions was designed to test section models of suspended bridges in wind tunnels. The two-degrees-of-freedom system and its versatility makes possible the study of many aeroelastic phenomena, such as galloping, vortex-induced vibrations, buffeting and flutter. Moreover, as a modular system is proposed, degrees of freedom can be easily removed or added as desired. Therefore, it can be used to study not only bridge aeroelasticity, but also fluid-structure interaction of other geometries. In order to verify the suspension system, galloping tests, using a square cylinder, and flutter tests, using a foil NACA 0020, were done at IPT\'s wind tunnel facility. The galloping response obtained for the square cylinder was consistent with the literature. On the other hand, the flutter derivatives obtained for the foil differ from those expected. Therefore, other investigations must be done in the future in order to identify the sources of the discrepancies observed.