The performance of an electric utility vehicle is very dependent on how it is used. The range can decrease significantly if there are many uphill along the route and if the vehicle carry a heavy load. The most important is that the vehicle never stops because lack of energy or power. The purpose of this thesis was to study how performance of the electric utility vehicle Nimbell Trigo were affected, depending on route, drive pattern and load. To study the performance, the parameters: battery current, state of charge and speed were analyzed. To analyze these parameters, a dynamic model of the vehicle has been created with Simulink. The model is based on physical relations and vehicle data. With the specifications for the vehicle and the force acting on it, energy consumption, battery current and power demand have been calculated with the Simulink model for specific routes and drive patterns. To validate the mode, three different routes were driven with Nimbell Trigo in Gothenburg and a simulation of the same routes and drive patterns were made with the Simulink model. The result from the validation shows that the dynamic model can predict the parameters of interest well, particularly the state of charge. The Simulink model can in the future be a time and cost efficient way, to analyze the performance of Nimbell Trigo and thereby replace test drives in an initial phase. / Marknaden för elektriska arbetsfordon har ökat de senaste åren i takt med dels ökade krav på miljövänliga alternativ, dels framsteg inom batteritekniken. Akilleshälen för de elektriska fordonen som grupp har varit energilagringen i batterierna. Erfordrad batteri- och motorstorlek är starkt kopplat till användningen av fordonet. Vid körningar med långa uppförsbackar samt tung last, förkortas räckvidden markant. Vid för höga belastningar på fordonet minskar maximala hastigheten och i längden kan motorn överhettas. För användaren är det av stor vikt att fordonet inte blir stillastående för att effekten eller energin inte räcker till. Syftet med detta examensarbete var att utreda hur det elektriska arbetsfordonet Nimbell Trigo presterar för olika rutter och körmönster, med en given last. För att utreda prestandan av fordonet skapades därför en dynamisk modell av Nimbell Trigo i det dynamiska simuleringsverktyget Simulink. De parametrar som valdes att studera var batterinivå som är kopplat till energin, batteriströmmen som är relaterad till effekten och i sin tur påverkar batterinivån, samt hastigheten som kan indikera när effekten inte räcker till. Med den dynamiska modellen kan effektbehov och energikonsumtion för en given sträcka beräknas på förhand. Fordonets hastighet, acceleration samt backtagningsförmåga erhålls för olika situationer från simuleringen. Dessa parametrar kan därmed studeras med avseende på olika motoralternativ genom att ange moment- och verkningsgradskurvan för motorn. Den dynamiska modellen validerades med testkörningar där Nimbell Trigo kördes en viss rutt med ett givet körmönster och last. Motorfrekvens, batteriström och batterinivå uppmättes. Dessa parametrar simulerades i modellen för samma rutt och körmönster. Mätvärdena från testkörningarna plottades mot de värden som erhölls från simuleringen. Resultatet visar att den dynamiska modellen som skapades stämmer bra överens mot uppmätta testdata. Den dynamiska modellen kan i framtiden komma att användas, för att på ett kostnads- och tidseffektivt sätt ersätta testkörningar i initiala studier av olika drivlinor och batterier.

In robotic systems, reduction of inertia is a key concern. One way to reduce the system inertia is to replace counterbalance masses with an equilibrator, which is a force element like a spring. Although there has been much research on equilibrated mechanisms, there has not much research on the control of these mechanisms. This thesis explores the PID control of equilibrated systems, and compares the results to the PID control of a common method of equilibration, the mass counterweight. Through modeling, simulating, and testing of the two systems, the equilibrated system response was found to be superior to the mass counterweight in measures of settling time and peak overshoot. / Master of Science

The basic oxygen furnace (BOF) is responsible for over 60% of the steel production worldwide. Despite being an old and intensively studied process, the complex dynamics of the phenomena taking place in the BOF still challenge researchers and fuel debates. Moreover, the severe operational conditions often prevent direct/continuous measurements of the states, making the process operation largely dependent on past experience and operators' knowledge. In this work, a dynamic model and optimization framework that can aid operators with the decision-making process are developed. Through several case studies, it is shown that the developed framework can potentially be used to reduce operational costs and increase productivity. / Thesis / Master of Chemical Engineering (MChE)

The rapid release of energy in mechanisms is often limited by conversion of potential energy to kinetic energy. The use of a flywheel to store energy over time eliminates this constraint. Using this principle, a lightweight and compact energy transmission mechanism has been developed for robotic combat applications. The purpose of the proposed design is to throw an opposing robot ten or more feet into the air. This design incorporates a flywheel, a self-resetting dog clutch with built in shock absorbing rubber for impact mitigation, and an optimized four-bar linkage to deliver the energy. A mathematical model of the dynamic system has been developed to analyze and aid in the design process. Testing of subsystems was performed to validate the design. A final design is proposed with the recommendation that it be built and tested. A validated design is applicable to many real-world problems that require rapid kinetic energy release including reconnaissance robots required to hop high fences.

This thesis develops and tests a two-dimensional discrete dynamic model for the simulation of granular flows in silos and hoppers. The granular material considered is assumed to be an assembly of viscoelastic discs and the motion of such a particle system is shown to be governed by a set of nonlinear first order ordinary differential equations. This system of equations is then solved numerically using the centered finite difference scheme. Based on the model presented, a computer program has been developed and used to analyse the flow behaviour of granular materials during filling and emptying of a silo. The results show that the discrete dynamic model developed is capable of modelling granular flows in silos, particularly predicting wall pressures and analysing flow blockage.

While some attempts have been made to model the behaviour of the grand piano action (the mechanism that translates a key press into a hammer striking a string), most researchers have reduced the system to a simple model with little relation to the components of a real action. While such models are useful for certain applications, they are not appropriate as design tools for piano makers, since the model parameters have little physical meaning and must be calibrated from the behaviour of a real action. A new model for a piano action is proposed in this thesis. The model treats each of the five main action components (key, whippen, jack, repetition lever, and hammer) as a rigid body. The action model also incorporates a contact model to determine the normal and friction forces at 13 locations between each of the contacting bodies. All parameters in the model are directly measured from the physical properties of individual action components, allowing the model to be used as a prototyping tool for actions that have not yet been built. To test whether the model can accurately predict the behaviour of a piano action, an experimental apparatus was built. Based around a keyboard from a Boston grand piano, the apparatus uses an electric motor to actuate the key, a load cell to measure applied force, and optical encoders and a high speed video camera to measure the positions of the bodies. The apparatus was found to produce highly repeatable, reliable measurements of the action. The behaviour of the action model was compared to the measurements from the experimental apparatus for several types of key blows from a pianist. A qualitative comparison showed that the model could very accurately reproduce the behaviour of a real action for high force blows. When the forces were lower, the behaviour of the action model was still reasonable, but some discrepancy from the experimental results could be seen. In order to reduce the discrepancy, it was recommended that certain improvements could be made to the action model. Rigid bodies, most importantly the key and hammer, should be replaced with flexible bodies. The normal contact model should be modified to account for the speed-independent behaviour of felt compression. Felt bushings that are modelled as perfect revolute joints should instead be modelled as flexible contact surfaces.

While some attempts have been made to model the behaviour of the grand piano action (the mechanism that translates a key press into a hammer striking a string), most researchers have reduced the system to a simple model with little relation to the components of a real action. While such models are useful for certain applications, they are not appropriate as design tools for piano makers, since the model parameters have little physical meaning and must be calibrated from the behaviour of a real action. A new model for a piano action is proposed in this thesis. The model treats each of the five main action components (key, whippen, jack, repetition lever, and hammer) as a rigid body. The action model also incorporates a contact model to determine the normal and friction forces at 13 locations between each of the contacting bodies. All parameters in the model are directly measured from the physical properties of individual action components, allowing the model to be used as a prototyping tool for actions that have not yet been built. To test whether the model can accurately predict the behaviour of a piano action, an experimental apparatus was built. Based around a keyboard from a Boston grand piano, the apparatus uses an electric motor to actuate the key, a load cell to measure applied force, and optical encoders and a high speed video camera to measure the positions of the bodies. The apparatus was found to produce highly repeatable, reliable measurements of the action. The behaviour of the action model was compared to the measurements from the experimental apparatus for several types of key blows from a pianist. A qualitative comparison showed that the model could very accurately reproduce the behaviour of a real action for high force blows. When the forces were lower, the behaviour of the action model was still reasonable, but some discrepancy from the experimental results could be seen. In order to reduce the discrepancy, it was recommended that certain improvements could be made to the action model. Rigid bodies, most importantly the key and hammer, should be replaced with flexible bodies. The normal contact model should be modified to account for the speed-independent behaviour of felt compression. Felt bushings that are modelled as perfect revolute joints should instead be modelled as flexible contact surfaces.

The diffusion of the Internet is the interest of many firms or individuals who see the Internet as an opportunity, a threat, or both. Huge amount of intellectual and real capital are invested on Internet. The more people understand the dynamics of Internet diffusion, the better they will manage the efforts put on it. The purpose of this study is to explore the extent to which the diffusion of the Internet-related innovation could be adequately described by the diffusion models and the effect of internal influence versus external influence described in the models. Two hypotheses of the Internet innovation diffusion are proposed. First, the number of potential adopters of the Internet innovation diffusion is dynamic, not constant. Second, in contrast to the traditional innovations, the diffusion of Internet innovation has stronger interpersonal communication influence than the promotional activity effect. Twelve Internet innovations are estimated in both the Bass model and the Dynamic model. The first hypothesis is fully supported, and the second hypothesis is partially supported. Based on the evidence, Internet innovations can be categorized into web-based versus non-web. The non-web Internet innovation of connection and communication like Internet, ADSL, and Skype has no significant difference of the ratio of the internal influence and the external influence effects to the traditional innovations. The segment-focused niche website, such as Amazon, eBay, and PayPal, has the strong internal influence effect. Understanding the various effects of Internet innovation diffusion can provide advantages in terms of enhancing functions and planning marketing strategies and tactics.

We present a method to determine the precise shape of a dynamic object from video. This problem is fundamental to computer vision, and has a number of applications, for example, 3D video/cinema post-production, activity recognition and augmented reality. Current tracking algorithms that determine precise shape can be roughly divided into two categories: 1) Global statistics partitioning methods, where the shape of the object is determined by discriminating global image statistics, and 2) Joint shape and appearance matching methods, where a template of the object from the previous frame is matched to the next image. The former is limited in cases of complex object appearance and cluttered background, where global statistics cannot distinguish between the object and background. The latter is able to cope with complex appearance and a cluttered background, but is limited in cases of camera viewpoint change and object articulation, which induce self-occlusions and self-disocclusions of the object of interest. The purpose of this thesis is to model self-occlusion/disocclusion phenomena in a joint shape and appearance tracking framework. We derive a non-linear dynamic model of the object shape and appearance taking into account occlusion phenomena, which is then used to infer self-occlusions/disocclusions, shape and appearance of the object in a variational optimization framework. To ensure robustness to other unmodeled phenomena that are present in real-video sequences, the Kalman filter is used for appearance updating. Experiments show that our method, which incorporates the modeling of self-occlusion/disocclusion, increases the accuracy of shape estimation in situations of viewpoint change and articulation, and out-performs current state-of-the-art methods for shape tracking.

In this thesis, a methodology for rigid body dynamic modeling and control design is presented for a 6 degree-of-freedom (DOF) parallel-kinematic-mechanism-based reconfigurable meso-milling machine tool (RmMT) with submicron tracking accuracy requirement. The dynamic modeling of the parallel kinematic mechanism (PKM) is formulated using the Lagrangian method with the application of principle of energy equivalence and coordinate transformations to separate the mechanism into serial sub-systems. The rigid body gyroscopic force is also modeled using this approach and its effect as a disturbance is analyzed and compensated. The contour errors for both position and orientation are formulated to increase machining accuracy. The dynamic model of the system is linearized through feedback linearization and the contour error based feedback control law is formulated using the convex combination design approach to satisfy a set of design specifications simultaneously. The dynamic model and its control methodology are simulated and verified within the MATLAB Simulink environment.