O objetivo do trabalho é melhorar o controle do comportamento dinâmico sob excitação vertical de um modelo veicular completo levando em consideração os três movimentos principais, de elevação (heave), balanço (pitch) e de rolagem (roll), em termos de aceleração. Com essa finalidade desenvolve-se a programação necessária para implementação de um modelo de veículo completo de 7 GDL no programa MATLAB® que interage com o sistema de controle ativo desenvolvido em diagrama de blocos no programa Simulink®. Em seguida, o desempenho do modelo é avaliado através de programas desenvolvidos de excitações de estrada com perfil senoidal e randômico. Os resultados obtidos mostram que o movimento da massa suspensa, em termos de aceleração, acima e abaixo do valor da frequência natural da roda pode ser diminuído pela filtragem dos coeficientes de mola e amortecimento através de um laço de controle interno, mais a utilização de amortecimento skyhook das velocidades de elevação, balanço e rolagem com um laço de controle externo. A atenuação das constantes de mola abaixo da frequência do corpo do veículo reduz as perturbações da estrada, mas podem bater nos limitadores do percurso da suspensão. / The aim of this work is to improve the control of the dynamic behavior under vertical excitation of a full vehicular model whilst taking into consideration the three main movements of heave, pitch and roll in terms of acceleration. With this goal in mind, the necessary programming was carried out for the implementation of a full vehicular model of 7 DOF using the software MATLAB® which interacts with the active control system developed via blocks diagram using the software Simulink®. Following on from that, the performance of the model is evaluated by means of programmes developed from road excitations with a sinusoidal and random profile. The results show that the motion of the sprung mass, in terms of acceleration, above and below the natural frequency of the wheel can be reduced by filtering the spring and damping coefficients through an internal control loop, plus the usage of skyhook damping of heave, pitch and roll velocities with an external control loop. The mitigation of the spring constants below the frequency of the body of the vehicle reduces the excitations of the road, but may strike against the path limiters of the suspension.

O uso de simulações computacionais no campo da engenharia vem se tornando cada vez mais freqüente. Este trabalho aplica diferentes tipos de análise, Método Multicorpos e Método dos Elementos Finitos, para estudos dinâmicos e estruturais, como ferramenta de auxílio no desenvolvimento de veículos terrestres. Através de métodos de integração numérica e posteriormente a utilização do método dos multicorpos, uma suspensão independente dianteira de um veículo foi isolada, considerada como um conjunto de corpos unidos por juntas, movidos por forças e restringidos por batentes. O comportamento dinâmico do sistema foi determinado submetendo o modelo a entradas provenientes do pavimento. O Método dos Elementos Finitos já é considerado como ferramenta potente para o cálculo estrutural. Para abordar tal tema, foi construído um modelo discretizado em Elementos Finitos de um veículo comercial completo. Este modelo foi submetido a simulações de situações de situações reais quasi-estáticas e dinâmicas, utilizando algoritmos implícito e explícito, dependendo do fenômeno considerado. A partir destes, puderam ser verificadas a performance estrutural e a segurança passiva do veículo arremessado a obstáculos cotidianos. O último estudo retrata que com a fusão dos métodos é possível, através de programas dedicados, prever a dinâmica de um modelo encriptado de um boneco tipo HYBRIDIII, quando submetido a um pulso de desaceleração no interior de um veículo com e sem bolsa de segurança(airbag). Todos os resultados obtidos foram comparados à realidade ou \"benchmark\". Os obstáculos enfrentados permitiram definir qual ferramenta melhor se encaixa num contexto de desenvolvimento dentro de uma corporação. / The use of computational tools in various engineering fields has increased over the last years. Mathematical modelling is identified as being the most adequate tool for simulating real service conditions along several product development phases. This work investigates different dynamic and structural analysis used for ground vehicle development tools. By numerical integration using the Multibody system method, an independent suspension was isolated from the car and considered as bodies connected by joints, moved by forces and constrained by stoppers. The dynamic behaviour of the systems was predicted when submitted to input exclusively from the ground. The Finite Element Method is already considered a very powerful simulation tool. In order to study the method, a full vehicle model was built and submitted to quasi-static and dynamic inputs. Both implicit and explicit methods were used to simulate different situations. The vehicle had its structural performance analysed related to durability and safety aspects. The last analysis that shows the fusion of methods is possible using dedicated computational tools to simulate the passenger kinematics by using an encrypted dummy and an airbag model under a deceleration pulse as input. AlI the results were compared to experimental and benchmark results. Also the difficulties emerged from each tool were pointed out in order to define which is the most appropriate within the development context.

O objetivo do trabalho é melhorar o controle do comportamento dinâmico sob excitação vertical de um modelo veicular completo levando em consideração os três movimentos principais, de elevação (heave), balanço (pitch) e de rolagem (roll), em termos de aceleração. Com essa finalidade desenvolve-se a programação necessária para implementação de um modelo de veículo completo de 7 GDL no programa MATLAB® que interage com o sistema de controle ativo desenvolvido em diagrama de blocos no programa Simulink®. Em seguida, o desempenho do modelo é avaliado através de programas desenvolvidos de excitações de estrada com perfil senoidal e randômico. Os resultados obtidos mostram que o movimento da massa suspensa, em termos de aceleração, acima e abaixo do valor da frequência natural da roda pode ser diminuído pela filtragem dos coeficientes de mola e amortecimento através de um laço de controle interno, mais a utilização de amortecimento skyhook das velocidades de elevação, balanço e rolagem com um laço de controle externo. A atenuação das constantes de mola abaixo da frequência do corpo do veículo reduz as perturbações da estrada, mas podem bater nos limitadores do percurso da suspensão. / The aim of this work is to improve the control of the dynamic behavior under vertical excitation of a full vehicular model whilst taking into consideration the three main movements of heave, pitch and roll in terms of acceleration. With this goal in mind, the necessary programming was carried out for the implementation of a full vehicular model of 7 DOF using the software MATLAB® which interacts with the active control system developed via blocks diagram using the software Simulink®. Following on from that, the performance of the model is evaluated by means of programmes developed from road excitations with a sinusoidal and random profile. The results show that the motion of the sprung mass, in terms of acceleration, above and below the natural frequency of the wheel can be reduced by filtering the spring and damping coefficients through an internal control loop, plus the usage of skyhook damping of heave, pitch and roll velocities with an external control loop. The mitigation of the spring constants below the frequency of the body of the vehicle reduces the excitations of the road, but may strike against the path limiters of the suspension.

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.

This master’s thesis deals with analysis and following optimisation of a Sigma TN sports car suspension. Knowledge of vehicle dynamics and strength of materials was used during the optimisation. Kinematic and force analysis was carried out in software ADAMS Car. A FEM analysis was processed in Ansys Workbench environment. Three design concepts were worked out, in which Topology optimisation also found use.

The ability to stand still in one place is important in a variety of activities of daily living. For persons with motion disorders, orthopaedic treatment, which changes geometric or biomechanical properties, can improve the individual'sposture and walking ability. Decisions on such treatment require insight in how posture and walking ability are aected, however, despite expectations based on experience, it is never a-priori known how a patient will react to a treatment. As this is very challenging to observe by the naked eye, engineering tools are increasingly employed to support clinical diagnostics and treatment planning. The development of predictive simulations allows for the evaluation of the eect of changed biomechanical parameters on the human biological system behavior and could become a valuable tool in future clinical decision making. In the first paper, we evaluated the use of the Zero Moment Point as a computationally inexpensive tool to obtain the ground reaction forces (GRFs) for normal human gait. The method was applied on ten healthy subjects walking in a motion analysis laboratory and predicted GRFs are evaluated against the simultaneously measured force plate data. Apart from the antero-posterior forces, GRFs are well-predicted and errors fall within the error ranges from other published methods. The computationally inexpensive method evaluated in this study can reasonably well predict the GRFs for normal human gait without using prior knowledge of common gait kinetics. The second manuscript addresses the complications in the creation and analysis of a posture prediction framework. The fmincon optimization function in MATLAB was used in conjunction with a musculoskeletal model in OpenSim. One clear local minimum was found in the form of a symmetric standing posture but perturbation analyses revealed the presence of many other postural congurations, each representing its own unique local minimum in the feasible parameter space. For human postural stance, this can translate to there being many different ways of standing without actually noticing a difference in the efforts required for these poses. / <p>This work was financially supported by the Swedish Scientic Council(Vetenskapsrådet) grant no. 2010-9401-79187-68, the ProMobilia handicapfoundation (ref. 13093), Sunnerdahls Handicap foundation (ansökan nr 11/14),and Norrbacka-Eugenia foundation (ansökan nr 218/15).</p><p></p><p></p>

Realism in animation sequences requires movements to be adapted to changing environments within the virtual world. To enhance visual experiences from animated characters, research is being focused on recreating realistic character movement adapted to surrounding environment within the character's world. Existing methods as applied to the problem of controlling character animations are often poorly suited to the problem as they focus on modifying and adapting static sequences, favoring responsiveness and reaching the motion objective rather than realism in characters movements.   Algorithms for synthesizing motion sequences can then bridge the gap between motion quality and responsiveness, and recent methods have shown to open the possibility to recreate specific motions and movement patterns. Effectiveness of proposed methods to synthesize motion can however be questioned, particularly due to the sparsity and quality of evaluations between methods. An issue which is further complicated by variations in learning tasks and motion data used to train models.   Rather than directly propose a new synthesis method, focus is put on refuting existing methods by applying them to the task of synthesizing objective-oriented motion involving the action of throwing a ball. To achieve this goal, two experiments are designed. The first experiment evaluates if a phase-functioned neural network (PFNN) model based on absolute joint configurations can generate objective oriented motion.   To achieve this objective, a separate approach utilizing a hierarchy of phase-function networks is designed and implemented. By comparing application of the two methods on the learning task, the proposed hierarchy model showed significant improvement regarding the ability to fit generated motion to intended end effector trajectories.   To be able to refute the idea of using dense feed-forward neural networks, a second experiment is performed comparing PFNN and feed-forward based network hierarchies. Outcome from the experiment show significant differences in favor for the hierarchy model utilizing phase-function networks.   To facilitate experimentation, objective oriented motion data for training network models are obtained by researching and implementing methods for processing optical motion capture data over repeated practices of over-arm ball throws. Contribution is then threefold: creation of a dataset containing motion sequences of ball throwing actions, evaluation of PFNN on the task of learning sequences of objective oriented motion, and definition of a hierarchy based neural network model applicable to the motion synthesis task.

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An important facet of creating high-quality vehicles is to create components that are quiet and smooth under operation. In reality, however, it is challenging to measure the sound that some automotive components make under load because it requires specialist facilities and equipment which are expensive to acquire. Furthermore, the motors used in testbeds drown out the noise emitted from much quieter components, such as a Power Transfer Unit (PTU). This thesis aims to solve these issues by outlining the steps required to virtually estimate the acoustic radiation of a PTU using the Transmission Error (TE) as the input excitation via multi-body dynamics (MBD). MBD is used to estimate the housing vibrations, which can then be coupled with an acoustic tool to create a radiation analysis. Thus, creating a viable method to measure the acoustic performance without incurring significant expenses. Furthermore, it enables noise and vibration analyses to be incorporated more easily into the design stage. This thesis analysed the sound radiated due to gear whine which arises due to the TE and occurs at the gear mesh frequency and its multiples. The simulations highlighted that the TE can be accurately predicted using the methods outlined in this thesis. Similarly, the method can reliably obtain the vibrations of the housing. The results from this analysis show that at 2000 rpm the PTU was sensitive to vibrations at 500, 1000 and 1500 Hz, the largest amplitude being at 1000 Hz. Furthermore, the Sound Power Level (SWL) was proportional to the vibration amplitudes in the system. Analytical calculations were conducted to verify the methods and showed a strong correlation. However, it was concluded that experiments are required to further verify the findings in this thesis. / En viktig aspekt i att skapa fordon av hög kvalitet är att skapa komponenter som är tysta och smidiga under drift. I verkligheten är det dock svårt att mäta ljudet som vissa fordonskompo- nenter ger under belastning eftersom det kräver specialanläggningar och utrustning, vilket är dyrt att skaffa. Dessutom maskerar motorerna som används i testbäddar ut bullret från mycket tystare komponenter, till exempel en kraftöverföringsenhet (PTU). Detta examensar- bete syftar till att lösa dessa problem genom att beskriva de steg som krävs för att virtuellt uppskatta den akustiska strålningen av en PTU med hjälp av transmissionsfelet (TE) som ingångsexcitation via flerkroppsdynamik (multi-body dynamics, MBD). MBD används för att uppskatta kåpans vibrationer, som sedan kan kopplas till ett akustiskt verktyg för att skapa en ljudutstrålningsanalys. Således skapas en genomförbar metod för att mäta den akustiska pre- standan utan att medföra betydande kostnader. Dessutom möjliggör det att lättare integrera ljud- och vibrationsanalyser i designfasen. Detta examensarbete analyserade ljudet som utstrålats på grund av kugghjulsljud, som uppstår på grund av TE och uppträder vid kuggingreppsfrekvensen och dess multiplar. Simuleringarna belyste att TE kan förutsägas exakt med de metoder som beskrivs i detta examensarbete. På samma sätt kan metoden på ett tillförlitligt sätt uppnå kåpans vibrationer. Resultaten från denna analys visar att vid 2000 rpm var PTU känslig för vibrationer vid 500, 1000 och 1500 Hz, den största amplituden var vid 1000 Hz. Dessutom var ljudeffektsnivån (SWL) proportionell mot vibrationsamplituderna i systemet. Analytiska beräkningar genomfördes för att verifiera metoderna och visade en stark korrelation. Dock drogs slutsatsen att experiment krävs för att ytterligare verifiera resultaten i detta arbete.

The design of the freight train truck has gone relatively unchanged over the past 150 years. There has been relatively little change to the fundamental railway truck design because of the challenges of implementing a cost effective and reliable modification to designs that have proven effective in decades of operation. A common U. S. railway truck consists of two sideframes, a bolster, two spring nests, and four friction wedges. The two sideframes sit on the axels. The bolster rides on springs on top of the sideframes. The friction wedges also ride on springs on top of the sideframe, and are positioned between the bolster and sideframe, acting as a damping mechanism. Better understanding the dynamic behavior and forces on the bodies are critical in reducing unnecessary wear on the components, along with potential negative behavior such as loss of productivity and increase in operating costs. This thesis will investigate the dynamic behavior of the truck under warping conditions using a stand-alone model created in Virtual.Lab. This research covers two main areas. First, the full-truck model will be developed and its simulation results will be compared to test data from the Transportation Technology Center, Inc. (TTCI). Data was provided from warp testing performed at the TTCI facilities in the spring of 2008. Once validated, the model will be used to gain a better understanding of the forces and moments that are propagated through the system, and of the dynamics of all bodies. Due to costs and physical constraints, not every bogie component can be instrumented during test, so the computer model will be able to provide valuable information not easily obtained otherwise. Second, full-truck models using different contact geometry between the wedges, sideframes, and bolster will be compared. A model with extremely worn sideframes will allow for investigation into the effects of wear on the damping abilities and warp stiffness of the truck. Another model using split wedges will be compared with the previous model to investigate into the behavior differences in the truck using different types of wedges. By understanding the impact of different geometries on the overall performance of the truck, better decisions on design and maintenance can be made in the future. After creating the models, we found that the full-truck model created in LMS® Virtual.Lab compared well with the test data collected by TTCI. In the comparison with NUCARS® we determined that the stand-alone model, which incorporates the wedges as bodies, captures the warp dynamics of the truck better than NUCARS®, which models the wedges as connections. By creating a model with severely worn sideframes, we were able to determine that the truck loses its abilities to damp bounce in the system as well as to prevent warping when the components become sufficiently worn. The split-wedge model behaved similarly to the standard full-truck model for bounce inputs, but had a significantly different behavior in warp. Further development will be needed on the split-wedge model to be confident that it behaved as expected. / Master of Science