This work highlights the design process to build a MBD (Multi-Body Dynamics) model with flexible parts for a RCV (Research Concept Vehicle). Full vehicle dynamic simulations of the RCV model with flexible parts were performed for different load cases and the results were compared with that of a MBD model with rigid body components. In addition, FE modelling of the RCV body parts, selection of attachment nodes, generation and verification of Modal Neutral Files (MNFs) are discussed. RCV is a concept vehicle developed at KTH Royal Institute of technology as a research platform to implement, validate and demonstrate results of various research projects. The vehicle consists of body, suspension and tire subsystems which were designed and developed as individual projects. The body subsystem comprises of rollcage, subframe and a composite baseplate. In this project, a MBD model of the RCV was developed in ADAMS/CAR to measure the forces acting at the interface of these body components and also to consider the suspension forces acting on the individual front and rear subframe parts. Finite element (FE) models were incorporated to consider the flexibility of the body components. The RCV is a vehicle constantly evolving with addition of new components to implement and test various research results. To study the application of this method, two Models of the RCV with design modifications were developed and studied. A model of the RCV without rollcage and a model with a rigid link connecting the body components were built and the results of dynamic simulations were compared with that of the existing RCV design. When flexibility of the baseplate was considered in the models, an overall change in dynamics of the body components was observed. Further, observing the results from models with design modifications, it was evident that this method can be used to study the effect of these modifications on the dynamic behaviour of the vehicle. / Det här arbetet belyser konstruktionsprocessen för att bygga en MBD-modell (Multi-Body Dynamics) med flexibla komponenter av konceptfordonet RCV (Research Concept Vehicle). Fullständiga fordonsdynamiska simuleringar med flexibla komponenter utfördes för olika lastfall och resultaten jämfördes med en MBD-modell med stela komponenter. Dessutom diskuteras FE modellering av RCVs olika delsystem, val av kopplingsnoder, generering och verifiering av ”Modal Neutral Files” (MNFs). RCV är ett konceptfordon som utvecklats vid Kungliga Tekniska Högskolan, KTH, som en forskningsplattform för att implementera, validera och demonstrera resultaten av olika forskningsprojekt. Fordonet består av delsystemen; chassi, hjulupphängning, och däck, vilka har utvecklats tidigare i separata projekt. Chassit består i sin tur av delsystemen; ”rollcage”, ”subframe” och ”baseplate”. I detta projekt har en MBD-modell av RCV utvecklats i ADAMS/CAR för att simulera olika körfall och beräkna de krafter som verkar mellan dessa delsystem och att också studera skillnaden i belastning av främre resp. bakre ”subframe”. FE modeller importeradesäven till modellen för att studera effekten av elasticiteten hos komponenterna på fordonets beteende.RVC är ett fordon som konstant utvecklas med tillägg av nya komponenter för att implementera och testa olika forskningsresultat. För att studera tillämpningen av denna metod skapades två modeller av RCV med olika konstruktiva förändringar vilkas inverkan på fordonet studerades. En modell av RCV utan ”rollcage” och en modell med styv länk som förbinder olika delar av chassit skapades och resultaten av dynamiska simuleringar jämfördes med simuleringsresultat för den befintliga RCV-designen. När flexibiliteten hos basplattan beaktades i modellerna observerades förändringar i dynamiken hos chassit vad gäller vertikala förskjutningar och vinkelförskjutningar. Utifrån dessa simuleringar kan vi dra slutsatsen att den utvecklade metoden är användbar för att studera effekter av konstruktionsförändringar på det dynamiska beteendet hos fordonet.

In today’s competitive automotive industry, most companies are trying to make their new designs and features implemented in their products to be ahead of their competitors. However, in the preliminary design stage of CEVT vehicles, dynamic simulation consumes excessive amount of time depending on the complexity of the dynamic model and simulation settings. It is beneficial and possible to shorten the simulation time. This thesis focuses on reducing the dynamic simulation time in ADAMS/Car in engine suspensions’ early development stage. Five simulation time reducing methods, i.e., reducing end time in driver control maneuver, stopping similar simulations, converting specific flexible parts to rigid parts, properly increasing the step size and performing simulation for engine suspension subsystem instead of the full vehicle system, were proposed and investigated separately to study their effects on the simulation time and the accuracy of the fatigue damage results of the engine suspension. With the proper combination of the five methods, total dynamic simulation time was effectively reduced to 61% and the variation of fatigue damage results of each engine suspension component was controlled within 30%. Dynamic modelling of an exhaust system is also included in this thesis and it provides referential data for the packaging design of exhaust system. / I dagens konkurrensutsatta bilindustri försöker de flesta företag att göra sina nya mönster och funktioner implementerbara i sina produkter för att vara före sina konkurrenter. I det preliminära konstruktionsstadiet av CEVT-fordon förbrukar dynamisk simulering dock en stor tid beroende på komplexiteten hos den dynamiska modellen och simuleringsinställningarna. Det är fördelaktigt och möjligt att förkorta simuleringstiden. Denna avhandling fokuserar på att minska den dynamiska simuleringstiden i ADAMS / Car i motorupphängningens tidiga utvecklingsstadium. Med hjälp av bakgrundsstudier och erfarenheter från CEVT’s personal provades fem olika sätt att minska simuleringstiden, samtidigt som simuleringsresultatens noggrannhet kontrollerades. Varje metod användes separat i simuleringen för att studera effekten på resultatens noggrannhet. I slutet kombineras alla metoder i simuleringen för att få bästa möjliga simuleringstid utan att förlora noggrannhet. Genom att kombinera de fem metoderna reducerades den totala dynamiska simuleringstiden till 61% och variationen i utmattningsskadans resultat av varje motorupphängningskomponent kontrollerades inom 30%. Dynamisk modellering av ett avgassystem ingår också i denna avhandling, vilket ger referensdata för framtida förpackningsdesign av avgassysteme

The purpose of this project is to continue the work on a vehicle model developed in ADAMS/Car and applied with the concept of ACM (Autonomous Corner Module). The project is divided up in two parts. The objective of the first part is to setup a co-simulation environment between ADAMS/Car and MATLAB/Simulink, and evaluate the vehicle model. In the second part a yaw controller is developed using only the rear wheel steering possibilities. The controller will be evaluated when it is applied on the vehicle model. The approach is to develop two models, one simpler in MATLAB/Simulink and one more complex in ADAMS/Car, and verify that they show similar behavior. The models will then be linearized and the control design will be based on the most appropriate linear model. Most of the work has been developing and evaluating the two vehicle models in ADAMS/Car and MATLAB/Simulink. The result was a working co-simulation environment where an evaluation of two different controllers was made. Due to linearization of the ADAMS model was nsuccessful, the controllers were based on the simpler linear Simulink model. Both controllers show similar results. Tests on the ADAMS model showed that it is hard to control both the yaw rate and body slip only by rear wheel steering.

<p>The purpose of this project is to continue the work on a vehicle model developed in ADAMS/Car and applied with the concept of ACM (Autonomous Corner Module). The project is divided up in two parts. The objective of the first part is to setup a co-simulation environment between ADAMS/Car and MATLAB/Simulink, and evaluate the vehicle model. In the second part a yaw controller is developed using only the rear wheel steering possibilities. The controller will be evaluated when it is applied on the vehicle model. </p><p>The approach is to develop two models, one simpler in MATLAB/Simulink and one more complex in ADAMS/Car, and verify that they show similar behavior. The models will then be linearized and the control design will be based on the most appropriate linear model. Most of the work has been developing and evaluating the two vehicle models in ADAMS/Car and MATLAB/Simulink. </p><p>The result was a working co-simulation environment where an evaluation of two different controllers was made. Due to linearization of the ADAMS model was nsuccessful, the controllers were based on the simpler linear Simulink model. Both controllers show similar results. Tests on the ADAMS model showed that it is hard to control both the yaw rate and body slip only by rear wheel steering.</p>

Suspension system is one of the most important subsystems in any automobile.An ideal system serves the occupant with comfort, minimal road disturbance, and thedriver with steer control and maneuverability.In the process of developing an ideal system, all the existing suspension systemsare reviewed by Pro-con analysis method, and McPherson suspension system is drawnout as most suitable system for Uniti car, as worked out from Pugh’s decision matrix.House of Quality is built to list out and prioritize technical specifications, userrequirements/ expectations for L7e car’s suspension. Quality Function Deploymentalso helped us to evaluate competitor strengths and weaknesses. The results obtainedfrom QFD is used as database to modify the existing predesigned McPhersonsuspension template that is available in ADAMS/Car 2015.1.0. Once the system wasmodified in the way it could fit the dimensions of Uniti car, it is tested and simulatedon test rig, whose results were out in the form of graphical plots between variousimportant suspension parameters.Parallel wheel travel, Opposite wheel travel, and Brake pull analysis are thetests conducted during simulation, whose results reveals that the modified suspensionsystem works efficiently for maximum working load and is stable on road to maneuvers.

When environmental laws are constricted and downsizing of engines has become the reality of the vehicle industry, there needs to be a solution for the rise in torsion vibrations in the drivetrain. These increased levels of torsion vibrations are mostly due to excitations from the firing pulses, which in turn have become increased due to higher cylinder pressures. One of the solutions for further dampening the system is to add a centrifugal pendulum absorber to the flywheel, and predicting the behaviour of such a device has become imperative.The intent of this thesis is to create a model that will accurately emulate the effectiveness and functionality of a centrifugal pendulum absorber, so that it can be used in simulations to predict vehicle behaviour with its addition. To validate the model, a comparison is made between simulated results, using the model created in Adams/Car and Matlab, and road measurements conducted using a prototype acquired by the industry.The results from the simulations show that, with existing theory on the subject and software provided by Scania, an accurate model can be created. The reduction of torsion vibrations is evident, and the model’s behaviour correlates to that of the prototype.Future work on the subject requires a larger insight into pendulums tuned to multiple orders, and an extension of the model geometry would be advantageous.

The diploma thesis deals with examinations of forces which are acting from road surface on tyres. The aim is to design and build measuring circuit which measure forces in front suspension. The thesis deals with designing of mathematical model in addition describes problematic of strain gauge sensors, their calibration and verification measure in details. The results are data obtained from static and dynamic measurement and outputs from multi-body system softwares. The results are evaluated and compared at conclusion.

The thesis focuses on investigating and optimizing a bushing script implemented as a tool in MSC ADAMS/Car. The study provides an insight on the representation of a rubber bushing and identify parameters which can be used to define the properties of a bushing in a simulation environment such as ADAMS/Car. The tool being studied here can be used to implement different kind of bushings such as a hydro bushing and a general rubber bushing, but optimization was implemented for the rubber bushing only. With an increasing reliance on Computer Aided Engineering (CAE) tools in the designing process, it is necessary that the vehicle behaviour can be predicted without relying on physical testing. CAE tools reduces the need of prototypes and provides a faster approach to designing vehicles. MSC ADAMS/Car is one such tool, which has been used here to predict the vehicle dynamic behaviour, which will influence the ride, handling and comfort characteristics of the vehicle. Rubber bushings, which have been studied here, have a significant contribution to the overall stiffness of the vehicle and as such, it is imperative that the tool being used here, is accurate and makes the designing process easy. The rubber bushing can be imagined to be a combination of a non-linear elastic spring, a frequency dependent Maxwell component and an amplitude dependent frictional element. In order to ease the design of the bushing properties, a reduced number of input properties are used to calculate the bushing properties internally. While trying to validate the force hysteresis loop obtained through the model with the measured data, it was seen that the accuracy was quite poor for the model when loading it with dynamic loads corresponding to amplitudes of0.2 mm and lower. The quasi-static loading and dynamic loading above 0.2 mm is shown to have a satisfactory accuracy when compared to the measured data.

Este trabalho tem como objetivo estudar a influência da geometria de suspensão do veículo nas atitudes da massa suspensa. Apresenta um confronto entre obras e autores e está segmentada em três partes; onde na primeira parte são definidos os conceitos básicos como dive, squat, lift, anti-dive, anti-squat, anti-lift e equivalente trailing-arm; na segunda parte são apresentadas as limitações e os novos conceitos definidos por R. S. Sharp e na terceira parte é apresentado o modelo dinâmico bidimensional introduzido por Fu-Cheng Wang. Apresenta um modelo virtual em sistema de multi-corpos desenvolvido no programa ADAMS, com todos os subsistemas que compõe um veículo completo. Inova ao trazer como objeto de estudo um veículo de competição (fórmula SAE) que possui como particularidade o sistema de suspensão push-rod. Surpreende com os resultados obtidos, pois, contrariam os conceitos básicos encontrados na maioria dos livros / This work has objective study the influence of suspension geometry on the sprung mass attitudes. It presents a confrontation among works and authors and this segmented in three parts; where in the first part the basic concepts are defined, dive, squat, lift, anti-dive, anti-squat, anti-lift and equivalent trailing-arm; in the second part the limitations are presented and the new concepts are defined for R. S. Sharp and in the third part are presented the bidimensional dynamic model introduced by Fu-Cheng Wang. It presents a virtual model in system of multi-bodies developed in the program ADAMS, with all the subsystems that composes a complete vehicle. It innovates when bringing such object to study one vehicle of competition (formula SAE) that it has a particularity suspension system push-rod. It surprises with results because it’s opposite of the basic concepts which is present in the majority of books

Este trabalho tem como objetivo estudar a influência da geometria de suspensão do veículo nas atitudes da massa suspensa. Apresenta um confronto entre obras e autores e está segmentada em três partes; onde na primeira parte são definidos os conceitos básicos como dive, squat, lift, anti-dive, anti-squat, anti-lift e equivalente trailing-arm; na segunda parte são apresentadas as limitações e os novos conceitos definidos por R. S. Sharp e na terceira parte é apresentado o modelo dinâmico bidimensional introduzido por Fu-Cheng Wang. Apresenta um modelo virtual em sistema de multi-corpos desenvolvido no programa ADAMS, com todos os subsistemas que compõe um veículo completo. Inova ao trazer como objeto de estudo um veículo de competição (fórmula SAE) que possui como particularidade o sistema de suspensão push-rod. Surpreende com os resultados obtidos, pois, contrariam os conceitos básicos encontrados na maioria dos livros / This work has objective study the influence of suspension geometry on the sprung mass attitudes. It presents a confrontation among works and authors and this segmented in three parts; where in the first part the basic concepts are defined, dive, squat, lift, anti-dive, anti-squat, anti-lift and equivalent trailing-arm; in the second part the limitations are presented and the new concepts are defined for R. S. Sharp and in the third part are presented the bidimensional dynamic model introduced by Fu-Cheng Wang. It presents a virtual model in system of multi-bodies developed in the program ADAMS, with all the subsystems that composes a complete vehicle. It innovates when bringing such object to study one vehicle of competition (formula SAE) that it has a particularity suspension system push-rod. It surprises with results because it’s opposite of the basic concepts which is present in the majority of books