<p>Estimation of the annular pressure at critical locations in the well is crucial for high-precision pressure control. Certain parameters which are important in order to determine the pressure profile of the well (in particular the friction factor, bulk modulus and density in the annulus), are encumbered with high uncertainty and are besides, continuously, but slowly changing. The objective of the thesis is to employ various Kalman filter designs estimation of the bottomhole pressure and certain important parameters/slowly varying variables, during drilling. Topics that should be addressed are: 1) Literature review of the theory of Kalman filters design 2) Design and implement an Extended Kalman filter (EKF) and possibly the Unscented Kalman filter (UKF) for a) Estimation of the annulus bottom-hole pressure b) Esimation of the friction coefficient, bulk modulus and density in the annulus 3) Analyse the performance/robustness of the observer in important cases, in particular: a) Pipe connection b) Pump ramp up/down 4) Examine observer performance to unmodeled dynamics by testing the Kalman filter against data sets from Wemod 5) Evaluate performance of the observer against experimental data from Grane.</p>

<p>This thesis develops a Dynamic Positioning (DP) system for small marine craft by using the LQR controller approach. Development has been done with a 'Viknes 830' vessel in mind, which is operated by the company 'Maritime Robotics AS' and will be equipped for DP operation the during summer of 2008. A Matlab-based simulator designed for DP simulations has been developed, and is used throughout the thesis. Furthermore, a Hardware-In-the-Loop (HIL) simulator has been used in order to localize and resolve as many implementation issues as possible prior to full-scale installation. A discussion on the general use of a HIL simulator for DP is included. Three variations of a feedback LQR station-keeping controller have been implemented and compared; a simple LQR controller, an LQR controller with modeled actuator dynamics, and nally an LQR controller with actuator dynamics and integral action. A feedforward controller has been added in order to provide enhanced station-keeping performance, as well as bumpless transfer from station keeping to low-speed maneuvering. A reference model has been created for smooth transfer in-between station-keeping reference points, and as input for the feedforward controller. A passive Luenberger DP observer has been applied in order to lter out high-frequency wave loads. Simulation results reveal that the LQR controller with actuator dynamics and integral action is most likely to perform well in real-life application. The largest performance enhancement is gained from the inclusion of actuator dynamics in the controller. It is discovered that the performance turns out better if the actuator dynamics is modeled faster in the controller due to unmodeled actuator saturation limits. V</p>

<p>This report considers the real-time implementation approach of an integration between an Inertial Navigation System (INS) and a Global Positioning System (GPS). The integration has been performed, using a GlobalSat EM--411 GPS receiver and a Microstrain 3DM--GX1 Inertial Measurement Unit (IMU). This has been performed by incorporating a Kalman filter, and aiding the INS estimates through GPS measurements. The goal of this thesis is to create an integrated application able to achieve performance of existing solutions three times the cost. The implementation has been made in real-time in c++, and off-line in Matlab. However the c++ code has not been sufficiently tested due to computer processing problems. Also the code has not been tested on an actual unmanned surface vehicle. The integrated solution worked sufficently when the GPS was online. However, during GPS droupout, the result is subject to high position drift, resulting in position errors of up to 400 meters after 20 seconds. Although it is unknown quite how large the position deviation of other, existing solutions are. However, high drift during GPS dropouts renders the IMU estimates quite useless for navigation. Thus this experiment has been unsuccessful.</p>

<p>In this thesis, we investige the applicability of the certain numerical methods for the solution of certain systems of partial differential equations. Numerical methods for this purpose are studied, in particular the finite element method. These systems arise from the study of extending performance analysis to general convergent nonlinear systems. It is argued that, for simplex meshes, the finite element method is not applicable to the systems. Further, it is argued that the finite element method should not be pursued as an alternative to the solution of these systems, as far better alternatives have recently been developed.</p>

<p>The focus of the work shall be on DVB-T PBR issues of range and Doppler migration of targets (of opportunity) in resolution cells due to high signal bandwidth and long integration time.</p>

<p>Piezoelectric tubes are commonly used as scanning actuators in nano precision microscopes. They can achieve precision down to sub-nanometer scale, but their vibrational dynamics and nonlinear properties hamper their ability to achieve higher bandwidths. In order to deal with this, further research is needed. This thesis is a first look into the field of piezoelectric tube actuators, intended to lay the groundwork for further research on the subject at NTNU. It details the construction of a laboratory setup for actuation and nanometer displacement measurement of a piezoelectric tube. Needed specifications are found and a mechanical setup is designed. Basic theory on piezoelectricity is presented, along with the setup and equipment used for the thesis. Several experiments are designed and conducted in order to identify the linear dynamics and nonlinear properties of the piezoelectric tube. The results are discussed and related to current literature. This includes the linear frequency responses from applied voltage to displacement of the piezoelectric tube, noise levels and nonlinear properties such as displacement creep and hysteresis. Generally, the results are found to closely match what has been found in similar research, although there are some notable differences, such as a somewhat smaller low frequency gain and a much lower resonant peak frequency of the system. Several possible explanations for these disparities are discussed. Both a capacitive sensor and a piezoelectric strain voltage sensor are utilized for measuring displacement. It is found that the capacitive sensor has a higher noise level but is more accurate at lower frequencies than the strain voltage sensor. The two measurements are then combined into an improved estimate of the displacement of the piezoelectric tube.</p>

<p>In this thesis, the compressor characteristics, being representations of the compressor pressure ratio as a function of the gas flow through the compressor, have been studied. Three different types of representations of the compressor characteristics are presented, implemented and tested with respect to simulation friendliness and effectiveness. These are based on a physical model, a 4th-order polynomial approximation method and a table lookup method. In addition, two different types of active surge controllers have been critically reviewed, i.e. the Close Coupled Valve (CCV) and the Drive Torque Actuation, and subsequently implemented and tested in SIMULINK. Based on the tests carried out on the compressor characteristics it is concluded that the 4th-order polynomial approximation method works best in an online environment. On the other hand, the table lookup method provides better representation of the actual data, but the method is somewhat slower compared to the other one. The usefulness of the physical model is limited, but together with parameter identification its applicability can be extended. Moreover, the active surge controllers have proved to be mathematically stable and shown to perform adequately. However, both face a problem with regard to measurement delay. Based on simulations and other considerations, the indications are that the drive torque actuation is the most promising solution for active surge control and should thus be the focus for further investigations. A possible solution for the measurement delay problem is to use a state observer. As a part of the thesis, two state observers have been implemented and tested, but with limited success.</p>

<p>The capture of gestures in order to use them as input for intuitive control has been investigated exhaustively in recent years. However, for the most part this has resulted in relatively expensive devices. The contribution of this report is the investigation on the feasibility of the development of a low-cost vision based input device for the tracking of head movements, concerning the use of them for motion control. The input device relies on the infrared camera, along with the built-in image analysis tools, present on a Nintendo Wii remote for the measurement of the location and orientation of a head-mountable marker. The marker consists of a set of optical feature points which are easily detectable, and organized in a fashion which allows for the determination of its position and orientation in space. The developed input device was then evaluated in order to determine the operating range, accuracy and robustness, and was shown to be feasible for its intended use. Finally, the implemented device was utilized to control a mechanical output device, being a unit capable of panning and tilting.</p>

<p>In many complex applications an accurate model of the plant is not known. Consequently, complementary methods are needed to automatically achieve accurate dynamical positioning of a robot in relation to its surroundings. This thesis describes the development of a control strategy on vision-based object tracking for a robot manipulator. To ensure necessary robustness we assume that four distinct, circular shapes are visible on the face of the object to inspect. Based on this information, along with knowledge of the camera parameters, the position and the orientation of the object are estimated. The developed system relies on the use of an open-source vision library, ViSP. A Kalman filter is used to predict future states of the moving object, in order to reduce tracking errors introduced by the response time of the system.</p>

<p>Floating Offshore Wind Power is an emerging and promising technology that is particularly interesting from a Norwegian point of view because of our long and windy coast. There are however still several remaining challenges with this technology and one of them is a possible stability problem due to positive feedback from tilt motion of the turbine tower. The focus of this report is to develope a simulator for a floating offshore wind turbine that includes individual, vibrating blades. Several controllers are developed, aiming to use the blade pitch angle and the generator power to control the turbine speed and output power, while at the same time limit the low-frequent motions of the tower and the high-frequent motions of the turbine blades. The prime effort is placed on developing a solution using Model Predictive Control(MPC). On the issue of blade vibrations no great progress has been made. It is not possible to conclude from the simulation results that the designed controllers are able to reduce the blade vibrations. However, the MPC controller works very well for the entire operating range of the turbine. A "fuzzy"-inspired switching algorithm is developed and this handles the transitions between the different operating ranges of the turbine convincingly. The problem of positive feedback from the tower motion is handled well, and the simulations do not indicate that this issue should jeopardize the viability of floating offshore wind turbines.</p>