Neste trabalho, uma análise quantitativa e qualitativa para a estabilização dinâmica de um pêndulo invertido com uma força externa senoidal aplicada no ponto de suspensão é feita. Inicialmente, a perturbação externa é composta de um único cosseno, então uma generalização é feita, usando uma soma de N cossenos com diferentes amplitudes e frequências. Aproximações são testadas e o tempo durante o qual o pêndulo invertido permanece estável é explorado quando N é grande, a fim de recuperar o padrão do caso onde N = 1. O caso específico de oscilações periódicas e quase periódicas, quando N = 2, é analisado e diagramas de estabilidade considerando diferentes frequências e amplitudes são estudados. Depois, um ruído Gaussiano additivo é adicionado ao sistema para que a degradação dos diagramas de estabilidade gerados por variâncias diferentes possam ser estudados. Todos os pontos deste trabalho são corroborados por simulações, as quais integram numericamente as equações de movimento do sistema através do método de Runge-Kutta de quarta ordem. Os algoritmos e detalhes extras dos métodos de integração usados são explorados numa publicação deste trabalho, a qual está apresentada, nesta dissertação, como um apêndice. / In this work a quantitative and qualitative analysis of the dynamical stabilization of an inverted pendulum with a sinusoidal external perturbation applied at the suspension point is made. Initially, the external perturbation is composed of a single cosine, then a generalization is made using a sum of N cosines with different amplitudes and frequencies. Approximations are tested, and the time for which the inverted pendulum remains stable is explored when N is large, in order to recover the pattern of the case when N = 1. The specific case of periodic and almost periodic oscillations, when N = 2, is analysed and stability diagrams considering different frequencies and amplitudes are studied. Later, an additive Gaussian noise is added to the system so the degradation of the stability diagrams generated by different variances can be studied. All points of this work are corroborated by simulations, which numerically integrate the system’s equation of motion through a fourth order Runge-Kutta method. Algorithms and extra details on the integration methods used are explored in a publication of this work, which is presented in this thesis as an appendix.

<p>A container crane of STS-type, Ship To Shore, consists of a spreader hanging underneath a railrunning trolly. As the container is under the influence of wind, it is likely that it starts to turn in a torsional pendulum. This report handles how the torsional pendulum of a container crane can be damped. </p><p>A number of different models have been developed to analyze how different placement of the actuators affects the system. Two differens types of controllers, LQG and MPC, have been developed and applied to these models. The different models and controlers were evaluated and compared by studying simulation results in timedomain. Moreover in order to make the simulations more realistic, a wind model has been developed and applied. </p><p>The models and controllers have been analyzed with bodediagrams and sensitivity functions. </p><p>The analyses shows clearly that the best placement of the actuators for control of the torsional pendulum on an STS-crane is in the trolly, pulling and relaxing the wires. This control is best handled by a state feedback control (LQG). Furthermore, the control should in this way, with addition of in the horizontalplane movable suspensions in the trolly, work acceptably in the whole operational area of a STS-crane.</p>

Tim Burtons films are largely thought to be exercises in style over content, and film adaptations in general are largely thought to be lesser than their source works. In this project, I argue that Burtons film <i>Sleepy Hollow</i>, an adaptation of Washington Irvings Legend of Sleepy Hollow, expresses his artistic message, that imagination and the irrational are equally valuable lenses through which to view the world as scientific process and reason are, while simultaneously complicating the thematic concerns of the longstanding myth of the headless horseman, the supernatural versus the natural and the irrational versus the rational, and relating them to his personal anxieties about the parent child relationship. I do so by drawing parallels between the film and its immediate source as well as <i>Sir Gawain and the Green Knight</i>, another chapter in the headless horseman myth, and two horror films from the 1960s. I compare the narrative structure, character relationships, thematic concerns, and cultural anxieties expressed in both the film and <i>Sir Gawain and the Green Knight</i> to demonstrate that the film argues for a worldview allowing the natural and the supernatural and the rational and the irrational to coexist. I also point to the visual references Burton makes to scenes from Roger Cormans <i>The Pit and the Pendulum</i> and Mario Bavas <i>La Maschera del Demonio</i>, illustrating the manner in which they complicate the myths thematic concerns. My argument adds to Hand and McRoys assertion that horror film adaptations are a form of myth-making and to the growing sense that there is more to Burtons art than flashy visuals.

A container crane of STS-type, Ship To Shore, consists of a spreader hanging underneath a railrunning trolly. As the container is under the influence of wind, it is likely that it starts to turn in a torsional pendulum. This report handles how the torsional pendulum of a container crane can be damped. A number of different models have been developed to analyze how different placement of the actuators affects the system. Two differens types of controllers, LQG and MPC, have been developed and applied to these models. The different models and controlers were evaluated and compared by studying simulation results in timedomain. Moreover in order to make the simulations more realistic, a wind model has been developed and applied. The models and controllers have been analyzed with bodediagrams and sensitivity functions. The analyses shows clearly that the best placement of the actuators for control of the torsional pendulum on an STS-crane is in the trolly, pulling and relaxing the wires. This control is best handled by a state feedback control (LQG). Furthermore, the control should in this way, with addition of in the horizontalplane movable suspensions in the trolly, work acceptably in the whole operational area of a STS-crane.

Tim Burtons films are largely thought to be exercises in style over content, and film adaptations in general are largely thought to be lesser than their source works. In this project, I argue that Burtons film <i>Sleepy Hollow</i>, an adaptation of Washington Irvings Legend of Sleepy Hollow, expresses his artistic message, that imagination and the irrational are equally valuable lenses through which to view the world as scientific process and reason are, while simultaneously complicating the thematic concerns of the longstanding myth of the headless horseman, the supernatural versus the natural and the irrational versus the rational, and relating them to his personal anxieties about the parent child relationship. I do so by drawing parallels between the film and its immediate source as well as <i>Sir Gawain and the Green Knight</i>, another chapter in the headless horseman myth, and two horror films from the 1960s. I compare the narrative structure, character relationships, thematic concerns, and cultural anxieties expressed in both the film and <i>Sir Gawain and the Green Knight</i> to demonstrate that the film argues for a worldview allowing the natural and the supernatural and the rational and the irrational to coexist. I also point to the visual references Burton makes to scenes from Roger Cormans <i>The Pit and the Pendulum</i> and Mario Bavas <i>La Maschera del Demonio</i>, illustrating the manner in which they complicate the myths thematic concerns. My argument adds to Hand and McRoys assertion that horror film adaptations are a form of myth-making and to the growing sense that there is more to Burtons art than flashy visuals.

The objective of this study is to reduce the interstory drifts, floor accelerations, and shear forces experienced by masonry houses subject to seismic excitation. Ambient vibration testing was performed on a case study structure in Maip�, Chile, to identify characteristics of the system. Upon creating a multiple degree-of-freedom (MDOF) model of the structure, the effect of implementing several base isolation techniques is assessed. The isolation techniques analyzed include the use of friction pendulum systems (FPS), high-damping rubber bearings (HDRB), two hybrid systems involving HDRB and shape memory alloys (SMA), and precast-prestressed pile (PPP) isolators. The dynamic behavior of each device is numerically modeled using analytical formulations and experimental data through the means of fuzzy inference systems (FIS) and S-functions. A multiobjective genetic algorithm is utilized to optimize the parameters of the FPS and the PPP isolation systems, while a trial-and-error method is employed to optimize characteristic parameters of the other devices. Two cases are studied: one case involves using eight devices in each isolation system and optimizing the parameters of each device, resulting in different isolated periods for each system, while the other case involves using the number of devices and device parameters that result in a 1.0 sec fundamental period of vibration for each baseisolated structure. For both cases, the optimized devices are simulated in the numerical model of the case study structure, which is subjected to a suite of earthquake records. Numerical results for the devices studied indicate significant reductions in responses of the base-isolated structures in comparison with their counterparts in the fixed-base structure. Metrics monitored include base shear, structural shear, interstory drift, and floor acceleration. In particular, the PPP isolation system in the first case reduces the peak base shear, RMS floor acceleration, peak structural shear, peak interstory drift, and peak floor acceleration by at least 88, 87, 95, 95, and 94%, respectively, for all of the Chilean earthquakes considered. The PPP isolation system in the second case (yielding a 1.0 sec period) and the FPS isolation systems in both cases also significantly reduce the response of the base-isolated structure from that of the fixed-base structure.

Η παρούσα διπλωματική έχει ως αντικείμενο την μελέτη των συστημάτων προώθησης και την εξέταση των δυνατοτήτων χρησιμοποίησης νέων μορφών προωθητηρίων. Συγκεκριμένα θεωρώντας ότι μέχρι σήμερα το κύριο σύστημα προώθησης UAV είναι οι DC κινητήρες σε συνδυασμό με έλικες μελετάται η δυνατότητα χρήσης Jet κινητήρων για την παραγωγή της απαιτούμενης ώσης που χρειάζεται ένα UAV κατά την αιώρηση. Οι στροβιλοκινητήρες έχουν την δυνατότητα παραγωγής σταθερής ώσης και χρησιμοποιούνται σχεδόν αποκλειστικά στα μεγάλης κλίμακας ιπτάμενα οχήματα. Υπάρχουν διάφοροι τύποι στροβιλοκινητήρων στην αγορά, οι οποίοι όμως βασίζονται στις ίδιες αρχές λειτουργίας. Κατά την εργασία μελετήθηκε ο μοντελιστικός Jet κινητήρας JetCat P20. Έγινε προσπάθεια μοντελοποίησης του εν λόγω κινητήρα λαμβάνοντας υπόψη όλα τα χαρακτηριστικά του. Το άγνωστο έως τώρα σύστημα μοντελοποιήθηκε και έγινε μελέτη της δυναμικής του. Οι Jet κινητήρες λόγω της φυσικών νόμων που τους διέπουν παρουσιάζουν σχετικά αργές αποκρίσεις. Οι σταθερές χρόνου αυτών των κινητήρων καθιστούν την δυνατότητα χρήσης τους σε UAV εφαρμογές αρκετά δύσκολη. Με την χρήση του JetCat P20 σε μια πραγματική εφαρμογή ελέγχου της γωνιάς ενός οδηγούμενου εκκρεμούς αναζητήθηκαν τα όρια και οι δυνατότητες ελέγχου αυτού του προωθητικού συστήματος. Οι Jet κινητήρες τελικά, όπως ο JetCat P20 έχουν αρκετά καλές δυνατότητες παραγωγής συγκεκριμένου επιπέδου ώσης, επομένως και ρύθμισης της γωνίας του εκκρεμούς, ωστόσο οι χρόνοι απόκρισής του είναι αρκετά μεγάλοι για τα δεδομένα UAV εφαρμογών, χωρίς να υπάρχουν πολλά περιθώρια βελτίωσης μέσω κλασσικού έλεγχου. / This thesis object is the study of propulsion systems and the examination of using new systems for propulsion. Especially, considering that until now the main propulsion system for UAV's are DC motors in combination with propellers we are examining the possibility of using Jet engine to generate the required thrust needed a UAV in hover. The turbines have the ability to produce constant thrust and are used almost exclusively in large-scale flight vehicles. There are different types of turbines on the market, but they are based on the same principles of operation. During this thesis, we are experimenting with the Jet engine JetCat P20. The Jet Engine system was modeled and we examined its dynamic.The Jet engines ,because of the physical laws governing them, have relatively slow time responses. The time constants of these motors makes it difficult to use in UAV applications. We have used the JetCat P20 in a real application ,where we tried to control the angle of a driven pendulum.The Jet engines finally, like JetCat P20 have pretty good production capabilities thrust level, and thus adjusting the angle of the pendulum, but their response time is large enough for the UAV applications, without much scope for improvement through classical control.

The aim of this thesis is to get a better understanding of the role of practical work in physics education in the Lao People’s Democratic Republic (Lao PDR). The Lao PDR is one of least developed countries in the world with a weak base for science, and poor market opportunities for science graduates. The rapidly expanding educational system has many problems concerning quality of the infrastructure and staff competence. A combination of qualitative and quantitative methods was used in the study in order to assure reliability of the results. Data was collected through questionnaires, interviews, video-recordings, and my own ethnographic experiences of working in the Lao educational system for more than thirty years. The study was informed and results analysed with help of curriculum perspective and Cultural-Historical Activity Theory (CHAT). The findings show that Lao physics education curriculum at all levels is dominated by very traditional forms of teaching with an almost total absence of practical. Official curricular documents have statements prescribing teachers to do practical work in high school and university courses. However, few institutions have functioning equipment and skilled teachers for organising practical activities. Therefore, the majority of Lao students come to university and even can finish university without experience of practical work in physics. This shows the gap that exists between intended and implemented curricula. The majority of the students understand the importance of having practical activities in physics. However, after being exposed to laboratory experiments in an introductory physics course, they expressed criticism about the quality of instruction and the process of the practical work organisation. The laboratory group work analysis showed that discussions were mainly focused on understanding the experimental procedures, manipulating equipment, and collecting data for the report rather than on the physics content (object of activity, in CHAT terms). Based on the research results, it is possible to suggest that a systemic approach is needed to stimulate the development of a new practical work culture in schools and universities. This approach should include training and incentives for science teachers, development of assessment strategies including practical work, maintenance structures for physics equipment, and technical support for the organisation of demonstrations and laboratory exercises.

The work is motivated by the goal of linking reality and model, and to see if there is an opportunity to develop an inexpensive educational tool for training in cyber-physical systems. This project has investigated the possibilities to build a cheap inverted pendulum with controller and connect this with the modeling language Acumen. Acumen models is used for comparison with the actual prototype. To solve these problems has a 3D printer been used to create hardware, Arduino UNO for control and Raspberry Pi for enable communication with Acumen over WLAN. The result was a cheap inverted pendulum, which can be built for a cost around 750 SEK. Graphs created in Acumen and from data collected from sensors can be analyzed. With a model of the inverted pendulum system, the results show that Acumen can be used in the development of cyber-physical systems. There are differences between model and reality but also similarities. / Arbetet motiveras av målet att knyta samman verklighet och modell, samt att se om det finns möjlighet att utveckla ett billigt utbildningsverktyg för utbildning i cyberfysiska system. Detta projekt har undersökt möjligheter att bygga en billig inverterad pendel med regulator samt koppla samman denna med modelleringsspråket Acumen. I Acumen skapa en modell av systemet och jämföra den med en fysisk prototyp. För att lösa dessa problem har en 3D skrivare använts för att skapa hårdvara. Arduino UNO för styrning och Raspberry Pi för att möjligöra kommunikation med Acumen över WLAN. Resultatet blev en billig inverterad pendel, som kan byggas för en kostnad runt 750 kr. Grafer från Acumen, och från data samlad från sensorer kan analyseras. Med en modell av en inverterad pendel visar resultaten att Acumen kan användas i utveckling av cyberfysiska system. Skillnader finns mellan modell och verklighet men även likheter.

Η παρούσα διπλωματική αφορά στον έλεγχο του ανεστραμμένου εκκρεμούς. Γίνεται μια σύντομη σύνοψη της σχετικής θεωρίας και ακολούθως ασχολείται αρχικά με τη σταθεροποίηση του γραμμικοποιημένου, γύρω από την ασταθή κατακόρυφη θέση ισορροπίας, συστήματος και στη συνέχεια με τη μελέτη δύο διαφορετικής λογικής ελέγχων για την πλήρη λύση του προβλήματος ελέγχου του εκκρεμούς, δηλαδή αφ’ ενός την ανύψωση και αφ’ ετέρου τη σταθεροποίηση του. Γίνεται και μια προσπάθεια εκτίμησης της περιοχής ελκτικότητας του συστήματος για κάποιους ελέγχους / In the present thesis the control of an inverted pendulum is presented. A brief summary of the relevant theory is presented. In the following the stabilization of the linearized system around the unstable upright position is developed. Furthermore, the study of two different control approaches for the complete solution of the pendulum; the swing up phase and stabilization phase. Lastly an effort for the rough estimation of the region of attraction is attempted