Mathematical models are designed for the Acrobot with Curved Links. From these models, the reduced system dynamics are derived, and used for a numerical search routine which aims to find a closed trajectory of a rolling motion without impact.

Offshore wind power has become a growing interest in the worldwide society. New research and investigation in this kind of technology is increasing year after year. Thus, the inspection on the offshore wind turbines is expensive but necessary.The goal of this project is to demonstrate the efficiency of a Remote Inspection System inside the nacelle of an Offshore Wind Turbine. The way of carrying out inspections on real nacelles, as well as other aspects from maintenance is discussed. Three different companies have been taken into account when developing an Inspection Plan.This master thesis contains a theoretical design of the input device that would be used in the future for inspection and maintenance tasks. A gamepad has been implemented as a temporary solution for the input device.It has been demonstrated how the prototype is able to detect failures in a scenario simulating a real nacelle. Although it has not been possible to test sound, heat or vibration, this kind of things would be easily detected by adding some more additional sensors.The conclusion is that a solution for reducing maintenance tasks relies on the development of effective condition monitoring and remote control systems.

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AbstractBy restricting a vehicle to the linear region of operation, with a small sideslip angle, a vehiclecannot achieve its full potential. By entering the nonlinear region of operation tightercorners can be achieved and some accidents could be prevented. Research is currently beingconducted to introduce drifting into vehicle safety systems, which currently restrict thevehicle to the linear region of operation. Vehicle drifting has been shown to have unstableequilibria, while still maintaining controllability.In this thesis, equilibria with sideslip angles ranging from -30 degrees to 30 are found fora nonlinear two-track model simulator. Analysis showed that simple mappings could bemade between the states and the inputs, and between the states themselves. All the linearisedsystems in these equilibria were found to be unstable, which coincides with currentresearch.In addition, this thesis presents an adaptive backstepping controller, which is used for convergeto an arbitrary sideslip angle, and when the drift is being initialised the controllermimics the behaviour of Power Over drifting technique. The adaptive part of the backsteppingcontroller is used as integral action that, by the use of adaptation, finds the stationarydeviation between the yaw rate and the desired yaw rate, which is added to the control law.A mapping between the desired sideslip angle and the desired yaw rate is used in a feedforward term such that the desired sideslip angle is achieved when the yaw rate converges.The controller has been tested with a modified Line Of Sight guidance system which providedthe controller with a desired sideslip angle. Robust response with respect to changesin vehicle mass and inertia was observed.

The focus of this thesis is obtaining useful segments of historic data from normal operation due to, for instance, economical and safety concerns of performing experiments on a plant. This will be done by development, and implementation of a user friendly concept. The concept will give the user a collection of search criteria to choose from, and the ability to combine them, to locate possible informative data in historic data. The angle of attack will be more practical than theoretical.The concept SHDMI is proposed as such a tool. As a prototype of the concept it shows promise dealing with both SISO- and MIMO-systems in its simplicity and structure, but it is concluded that improvements and/or expansions of SHDMI is needed if it is to become a reliable and adequate for its purposes.

Det er blitt utviklet en elektrode for samtidig måling av overflateelektromyografi og kontaktkraften mellom elektroden og huden. Forsøk er gjort med kontraksjon av flexor carpi radialis samtidig som ekstern kraft er påført EMG-elektroden for å framprovosere bevegelsesartefakter i målingen.De teoretiske sammenhengene mellom økt kontaktkraft og bevegelsesartefakter er utredet.Det er benyttet lineære- og kvadratiske mappingfunksjoner i tillegg til et flerlags perseptronnettverk og genetisk programmering for å undersøke sammenhenger mellom påtrykt kraft og målt bevegelsesartefakt ved å estimere den reelle muskelkraften.Det er funnet en bedring av estimert muskelkraft når både EMG og kontaktkraftmålingen er benyttet (RMSE-verdier redusert med opp til 30%) i forhold til tilfellet med kun EMG. Dette tyder på at det er funnet sterke sammenhenger mellom kontaktkraft og bevegelsesartefakt. Høypassfiltrering av det målte EMG-signalet på 20Hz fjerner det meste av bidraget fra artefaktene og lineære mappingfunksjoner gir gode resultater. På mindre filtrert data gir metodene høyere RMSE-verdier og genetisk programmering gir de minste RMSE-verdiene (halvparten av førsteordens mappingfunksjoner) mens maksimalt avvik er noe høyere enn andre metoder.Ingen av metodene benyttet fjerner hele bidraget fra bevegelsesartefaktene, men resultatene viser at det er sammenhenger mellom målt kontaktkraft og bevegelsesartefakter og at denne sammenhengen kan utnyttes til å bedre muskelkraftestimat.

Et av de mer opplagte problemene som møter en person hvis arm har blitt erstattet med en protese, er reduksjonen i antall mulige bevegelser som en protese har i forhold til en frisk arm. Studier foretatt på friske armer, viser et større repertoar av bevegelser når håndleddets rotasjonsakse er stilt på skrå i forhold til underarmens lengdeakse. Et pågående forskningsprosjekt har som mål å undersøke om disse resultatene kan brukes til å hjelpe protesebrukere, og i den anledning har det blitt laget et håndledd med mulighet for vinkling av rotasjonsaksen.Gjennom bruk av en utviklingsmetodikk med navn V-modellen har denne oppgaven, som fortsettelse på tidligere arbeid, forsøkt å lage et fungerende styresystem for håndleddet. Underveis i arbeidet har utviklingsmetodikkens faser blitt fulgt, og all nødvendig dokumentasjon og planer for testing har blitt testet.Maskinvaren til håndleddets styresystem har blitt modularisert og designet for å håndtere sine tilordnede oppgaver. Kretsskjema for hver modul ble tegnet og lagt ut på flere kretskort som deretter kunne stables for å realiserte en prototyp av hele systemet. Programvare for hver av maskinvarens moduler har også blitt skrevet.Av testingen som har blitt gjennomført, vises det at den realiserte prototypen tilfredsstiller kravene fra funksjons- og teknisk spesifikasjon.

The main purpose of this thesis has been to identify the general usage of the applications textit{inhibit} and textit{override} for a collection of installations operated by Statoil ASA. The applications are provided by a Safety and Automation System (SAS) that performs monitoring, control and safeguarding of the plant and its process. Logs that keep track of the SAS operator's actions and other facility-related events have been received from each installation, and regarded with respect to:* the general evolvement and trend of the application usage* instances of inhibits/overrides of long-term character* redundant signals that are inhibited/overridden simultaneously* critical time periods that exhibit high activity* tags that are frequently involved in the application usageThe results that were obtained for each above-mentioned point made it possible to give a stetement of how the installations are controlled through utilization of the safety-impairing, but useful applications.

Managed pressure drilling is a sophisticated pressure control method which is intended to meet increasingly high demands in drilling operations in the oil and gas industry. With this method, the well is pressurized and the drilling mud is released through a control choke which can be used to actively control/reject pressure variations. Such a control system needs to handle several disturbances, and in particular, vertical motion of the drill string causes severe pressure variations that need to be compensated by active use of the control choke. In this thesis we first analyze data from previous experiments with an existing control strategy and show that the main reason for the poor disturbance rejection is due to a control strategy based on an insufficient model of the pressure fluctuations, although practical issues like sampling time and choke friction also played a part. Then, we present several different control strategies for regulation of both top side and bottom hole pressures based on more detailed models of the well pressure dynamics. All controllers are tested in simulations and it is shown that either an output regulation controller or a controller based on the internal model principle will achieve satisfactory disturbance rejection. Lastly, some of these controllers are also tested on a high fidelity drilling simulator from IRIS, and a pressure regulation within plus/minus 0.5 bar is achieved for the choke pressure, and plus/minus 1.5 bar for the bottom hole pressure.

This thesis contains the synthesis, analysis and simulation results of an automatic optimal voltage controller for the Southern Norwegian power grid. Currently the high voltage power grid is controlled manually by operators switching control components. The optimal controller handles the voltage control of the system, as well as keeping the number of control actions to a minimum.The system model is derived from power system analysis. Due to a highy nonlinear system model and integer decission variables in on/off control components, the controller is based on mixed integer nonlinear programming (MINLP). The MINLP uses BONMIN as a solver, and is implemented with the AMPL programming language.It was found that a MINLP controller is good choice for voltage control in transmission systems. The controller handles voltage limits, as well as reducing the number of control actions.The thesis also contains comparison between different solution methods for applying the optimal voltage controller, as well as other approaches to the automatic voltage control problem.