The purpose of this thesis was to design, construct and control a robotic arm with six degrees of freedom. The arm should be able to do simple tasks such as pick and place with good accuracy and without using external sensors. This thesis investigates the precision and the strength of the constructed robot arm. The arm was constructed using 3D printed parts and commonly available hardware such as threaded rods, bearings, screws and nuts. Each axis uses a combination of pulleys and belts in order to achieve desired torque. A differential transmission was implemented in four of the axes in order to combine the power of the motors and reduce weight in the upper parts of the arm. The robot is driven by six stepper motors that are controlled by a combination of RAMPS 1.4 shield and Arduino Mega 2560 microcontroller. The user can manipulate each axis by sending commands to the Arduino through an USB cable. The commands are generated with the help of a simple user interface written in Python. Experiments have shown that the arm has an average error increase of 0.0289-0.1356 mm for each movement, depending on the chosen speed. The maximum amount ofweight that the arm can hold in the worst case scenario is 0.84 kg. / Syftet med denna avhandling var att designa, konstruera och kontrollera en robotarm med sex frihetsgrader. Armen ska kunna utföra enkla uppgifter som pick-and-place med god noggrannhet och utan användning av externa sensorer. Denna avhandling underosöker precisionen och styrkan hos den konstruerade robotarmen. Armen konstruerades med 3D-printade delar och läattillgänglig hårdvara som gängstänger, lager, skruvar och muttrar. Varje axel använder en kombination av kuggremskivor och kuggremmar för att uppnå önskat moment. En differentialväxel användes i fyra av axlarna för att kombinera motorernas moment och minska vikten i armens övre delar. Roboten drivs av sex stegmotorer som styrs av en kombinationav RAMPS 1.4-shield och Arduino Mega 2560 mikrokontroller. Användaren kan styra varje axel genom att skicka kommandon till Arduinon via en USB-kabel. Kommandona genereras med hjälp av ett enkelt användargränssnitt skrivet i Python. Experiment har visat att armen har en genomsnittlig felökning på 0,0289-0,1356 mm för varje rörelse, beroende på vald hastighet. Den högsta vikt som armen i värsta fallkan håalla är 0,84 kg.

This thesis presents a framework for a hybrid model-free marker-less inertial-visual camera pose tracking with an integrated sensor fusion mechanism. The proposed solution addresses the fundamental problem of pose recovery in computer vision and robotics and provides an improved solution for wide-area pose tracking that can be used on mobile platforms and in real-time applications. In order to arrive at a suitable pose tracking algorithm, an in-depth investigation was conducted into current methods and sensors used for pose tracking. Preliminary experiments were then carried out on hybrid GPS-Visual as well as wireless micro-location tracking in order to evaluate their suitability for camera tracking in wide-area or GPS-denied environments. As a result of this investigation a combination of an inertial measurement unit and a camera was chosen as the primary sensory inputs for a hybrid camera tracking system. After following a thorough modelling and mathematical formulation process, a novel and improved hybrid tracking framework was designed, developed and evaluated. The resulting system incorporates an inertial system, a vision-based system and a recursive particle filtering-based stochastic data fusion and state estimation algorithm. The core of the algorithm is a state-space model for motion kinematics which, combined with the principles of multi-view camera geometry and the properties of optical flow and focus of expansion, form the main components of the proposed framework. The proposed solution incorporates a monitoring system, which decides on the best method of tracking at any given time based on the reliability of the fresh vision data provided by the vision-based system, and automatically switches between visual and inertial tracking as and when necessary. The system also includes a novel and effective self-adjusting mechanism, which detects when the newly captured sensory data can be reliably used to correct the past pose estimates. The corrected state is then propagated through to the current time in order to prevent sudden pose estimation errors manifesting as a permanent drift in the tracking output. Following the design stage, the complete system was fully developed and then evaluated using both synthetic and real data. The outcome shows an improved performance compared to existing techniques, such as PTAM and SLAM. The low computational cost of the algorithm enables its application on mobile devices, while the integrated self-monitoring, self-adjusting mechanisms allow for its potential use in wide-area tracking applications.

In this thesis, a simulation package for the Six Degrees of Freedom (6DOF) motion of an underwater vehicle is developed. Mathematical modeling of an underwater vehicle is done and the parameters needed to write such a simulation package are obtained from an existing underwater vehicle available in the literature. Basic equations of motion are developed to simulate the motion of the underwater vehicle and the parameters needed for the hydrodynamic modeling of the vehicle is obtained from the available literature. 6DOF simulation package prepared for the underwater vehicle was developed using the MATLAB environment. S-function hierarchy is developed using the same platform with C++ programming language. With the usage of S-functions the problems related to the speed of the platform have been eliminated. The use of Sfunction hierarchy brought out the opportunity of running the simulation package on other independent platforms and get results for the simulation.

This thesis documents the studies conducted in deriving a mathematical model representing the dynamics of a maneuvering ship to be implemented as part of an interactive real-time simulation system, as well as the details and results of the implementation process itself. Different effects on the dynamics of ship motions are discussed separately, meaning that the effects are considered to be applied to the system one at a time and they are included in the model simply by the principle of superposition. The model is intended to include the hydrodynamic interactions between the ship hull and the ocean via added mass (added inertia), damping and restoring force concepts. In addition to these effects, which are derived considering no incident waves are present on the ocean, the environmental disturbances, such as wind, wave and ocean current are also taken into account for proposing a mathematical model governing the dynamics of the ship. Since the ultimate product of this thesis work is a running computer code that can be integrated into an available simulation software, the algorithm development and code implementation processes are also covered. Improvements made on the implementation to achieve &ldquo / better&rdquo / real-time performance are evaluated comparatively in reference to original runs conducted before the application of improvement under consideration. A new method to the computation of the wave model that allows faster calculation in real-time is presented. A modular programming approach is followed in the overall algorithm development process in order to make the integration of new program components into the software, such as a new hull or propulsion model or a different integrator type possible, easily and quickly.

The omnicopter is a small unmanned aerial vehicle capable of executing decoupled translational and rotational motion (six degree of freedom, 6DOF, motion). The development of controllers for various 6DOF controllable multirotors has been much more limited than development for quadrotors, which makes selecting a controller for a 6DOF multirotor difficult. The omnicopter is subject to various uncertainties and disturbances from hardware changes, structural dynamics, and airflow, making adaptive controllers particularly interesting to investigate. The goal of this research is to design and evaluate the performance of various position and attitude controller combinations for the omnicopter, specifically focusing on adaptive controllers. Simulations are first used to compare combinations of three position controllers, PID, model reference adaptive control, augmented model reference adaptive control (aMRAC), and four attitude controllers, PI/feedback linearization (PIFL), augmented model reference adaptive control, backstepping, and adaptive backstepping (aBack). For the simulations, the omnicopter is commanded to point at and track a stationary aim point as it travels along a $C^0$ continuous trajectory and a trajectory that is $C^1$ continuous. The controllers are stressed by random disturbances and the addition of an unaccounted for suspended mass. The augmented model reference adaptive controller for position control paired with the adaptive backstepping controller for attitude control is shown to be the best controller combination for tracking various trajectories while subject to disturbances. Based on the simulation results, the PID/PIFL and aMRAC/aBack controllers are selected to be compared during three different flight tests. The first flight test is on a $C^1$ continuous trajectory while the omnicopter is commanded to point at and track a stationary aim point. The second flight test is a hover with an unmodeled added weight, and the third is a circular trajectory with a broken blade. As with the simulation results, the adaptive controller is shown to yield better performance than the nonadaptive controller for all scenarios, particularly for position tracking. With an added weight or a broken propeller, the adaptive attitude controller struggles to return to level flight, but is capable of maintaining steady flight when the nonadaptive controller tends to fail. Finally, while model reference adaptive controllers are shown to be effective, their nonlinearity can make them difficult to tune and certify via standard certification methods, such as gain and phase margin. A method for using time delay margin estimates, a potential certification metric, to tune the adaptive parameter tuning gain matrix is shown to be useful when applied to an augmented MRAC controller for a quadrotor. / Doctor of Philosophy / The omnicopter is a small unmanned aerial vehicle capable of executing decoupled translational and rotational motion. The development of controllers for these types of vehicles has been limited, making controller selection difficult. The omnicopter is subject to variations in hardware and airflow, making adaptive controllers particularly interesting to investigate. The goal of this research is to design and compare the performance of various position and attitude controller combinations for the omnicopter, specifically focusing on adaptive controllers. Simulations are first used to compare combinations of several position and attitude controllers on various trajectories and disturbances. Simulation results showed that a fully adaptive controller combination produced the best trajectory tracking while subject to disturbances. As with the simulation results, flight tests showed the adaptive controller yields better performance than the nonadaptive controller for all scenarios, particularly for position tracking. Finally, while the adaptive position controller was shown to be effective, it is difficult to tune and certify for widespread use. A method for using time delay margin estimates, a potential certification metric, to tune the adaptive controller is shown to be useful when applied to an adaptive controller for a quadrotor.

Spacecraft missions such as spacecraft docking and formation flying require high precision relative position and attitude data. Although Global Positioining Systems can provide this capability near the earth, deep space missions require the use of alternative technologies. One such technology is the vision-based navigation (VISNAV) sensor system developed at Texas A&M University. VISNAV comprises an electro-optical sensor combined with light sources or beacons. This patented sensor has an analog detector in the focal plane with a rise time of a few microseconds. Accuracies better than one part in 2000 of the field of view have been obtained. This research presents a new approach involving simultaneous activation of beacons with frequency division multiplexing as part of the VISNAV sensor system. In addition, it discusses the synchronous demodulation process using digital heterodyning and decimating filter banks on a low-power fixed point DSP, which improves the accuracy of the sensor measurements and the reliability of the system. This research also presents an optimal and computationally efficient six-degree-of-freedom estimation algorithm using a new measurement model based on the attitude representation of Modified Rodrigues Parameters.

Spacecraft missions such as spacecraft docking and formation flying require high precision relative position and attitude data. Although Global Positioining Systems can provide this capability near the earth, deep space missions require the use of alternative technologies. One such technology is the vision-based navigation (VISNAV) sensor system developed at Texas A&M University. VISNAV comprises an electro-optical sensor combined with light sources or beacons. This patented sensor has an analog detector in the focal plane with a rise time of a few microseconds. Accuracies better than one part in 2000 of the field of view have been obtained. This research presents a new approach involving simultaneous activation of beacons with frequency division multiplexing as part of the VISNAV sensor system. In addition, it discusses the synchronous demodulation process using digital heterodyning and decimating filter banks on a low-power fixed point DSP, which improves the accuracy of the sensor measurements and the reliability of the system. This research also presents an optimal and computationally efficient six-degree-of-freedom estimation algorithm using a new measurement model based on the attitude representation of Modified Rodrigues Parameters.

The advance of digitization influences medical sciences in various areas, increasingly including medical education. Therefore the Teaching Department of the Medical Faculty of the University of Leipzig constantly considers new technical developments and their possibilities for use in medical teaching. The focus is on the fact that teaching should be supplemented and explicitly not replaced by digital media. Virtual reality (hereinafter referred to as 'VR') represents a technology that can be expected to offer promising potential. In order to determine to what extent VR represents an added value for the study of human medicine and which hardware and software is suitable, the project VRmed – Virtual Reality in Medical Teaching was initiated in the Media section of the Teaching Department of the MF. This was funded as part of the Digital Fellowship Program by the University Didactic Center Saxony and the Working Group E-Learning of the LRK Saxony. The present report represents the final report of the project, which was created on its own initiative. In order to investigate the question of implementation possibilities for medical studies, four VR glasses (three different models) and four VR applications were purchased. Two simulation applications and two anatomy applications were selected as applications. The former are i:medtasim and StepVR applications. In addition, the anatomy applications 3D Organon VR Anatomy and Medicalholodeck were purchased. The initially extensive multi-stage evaluation with lecturers and students could not be implemented in 2020/2021 due to the pandemic-related restrictions and was therefore only applied in limited extent. Thus, hardware and software were evaluated qualitatively and in depth in the context of three presentation events by lecturers and media didactics. In particular, the simulation applications are considered to be helpful and useful extensions for teaching. The anatomy application 3D Organon VR Anatomy could also be used profitably in medical studies, especially in the early semesters. With regard to i:medtasim, there are initial considerations to include this in the curriculum as part of a medical elective. Another perspective is the establishment of a VR lab in which students and lecturers can freely use the technology. It should also be noted that VR is associated with many technical challenges and both the setup and the first use require expertise. In addition, the purchase is cost-intensive and hardware and software develop very quickly. Nevertheless, the potentials and the added value predominate. VR can be used to meet a wide range of learning types, practice scenarios bridge the gap between theory and practice, and students and lecturers can connect to technical developments.:1. Einleitung 2. Theoretische Hinführung 3. VR an Medizinischen Fakultäten und Universitäten außerhalb des Standorts Leipzig 4. Projektbeschreibung VRmed – Virtual Reality in der medizinischen Lehre Leipzig 5. VR Hardware und Software für den medizinischen Einsatz 6. Evaluation 7. Fazit und Ausblick 8. Literaturverzeichnis 9. Online-Quellen Anhang A) Projektstrukturplan B) Zeitplan C) Poster D) Evaluationsprotokolle / Das Voranschreiten der Digitalisierung beeinflusst die Medizin in verschiedenen Bereichen, weshalb deren Relevanz auch im Medizinstudium zunimmt. Daher werden im Referat Lehre der Medizinischen Fakultät der Universität Leipzig stetig neue technische Entwicklungen und deren Möglichkeiten für den Einsatz in der medizinischen Lehre betrachtet. Im Fokus steht, dass die Lehre ergänzt und explizit nicht durch digitale Medien ersetzt werden soll. Virtual Reality (im Folgenden „VR“) stellt dabei eine Technologie dar, die in der ersten Auseinandersetzung vielversprechende Potentiale erwarten lässt. Um festzustellen, inwiefern VR einen Mehrwert für das Humanmedizinstudium darstellt und welche Hard- und Software dabei in Frage kommt, wurde im Bereich Medien des Referats Lehre der MF das Projekt VRmed – Virtual Reality in der medizinischen Lehre initiiert. Dies wurde im Rahmen des Digital Fellowship-Programms vom Hochschuldidaktischen Zentrum Sachsen und dem Arbeitskreis E-Learning der LRK Sachsen gefördert. Der hier vorliegende Bericht stellt den Abschlussbericht des Projektes dar, welcher aus Eigenantrieb erstellt wurde. Um der Frage nach Implementierungsmöglichkeiten für das Medizinstudium nachzugehen, wurden vier VR-Brillen (drei verschiedene Modelle) und vier VR-Anwendungen angeschafft. Als Anwendungen wurden zwei Simulationsanwendungen und zwei Anatomieanwendungen ausgewählt. Bei ersterem handelt es sich um die Anwendungen i:medtasim und StepVR. Zudem wurden die Anatomieanwendungen 3D Organon VR Anatomy und Medicalholodeck eingekauft. Die zunächst umfangreich angelegte mehrstufige Evaluation mit Dozierenden und Studierenden konnte aufgrund der pandemiebedingten Einschränkungen in den Jahren 2020/2021 nicht umgesetzt werden und wurde eingegrenzt. Somit wurde Hard- und Software im Rahmen von drei Präsentationsveranstaltungen von Dozierenden und Mediendidaktiker:innen qualitativ und tiefgehend evaluiert. Insbesondere die Simulationsanwendungen werden als hilfreiche und sinnvolle Erweiterungen für die Lehre eingeschätzt. Auch die Anatomieanwendung 3D Organon VR Anatomy könnte im Medizinstudium, insbesondere in die frühen Semester, gewinnbringend eingesetzt werden. Bezüglich i:medtasim existieren erste Überlegungen, dies im Rahmen eines humanmedizinischen Wahlfachs in das Curriculum einzubinden. Eine weitere Perspektive ist die Etablierung eines VR-Labs, in dem Studierende und Dozierende die Technik frei nutzen können. Es bleibt auch festzuhalten, dass VR mit vielen technischen Herausforderungen verbunden ist und sowohl das Einrichten als auch die erste Nutzung Expertise bedürfen. Zudem ist die Anschaffung kostenintensiv und Hard- und Software entwickeln sich sehr schnell. Dennoch überwiegen die Potentiale und der Mehrwert. Durch VR kann vielfältigen Lerntypen begegnet werden, durch Übungsszenarien wird eine Brücke zwischen Theorie und Praxis geschlagen und Studierende wie auch Dozierende können an technische Entwicklungen anschließen.:1. Einleitung 2. Theoretische Hinführung 3. VR an Medizinischen Fakultäten und Universitäten außerhalb des Standorts Leipzig 4. Projektbeschreibung VRmed – Virtual Reality in der medizinischen Lehre Leipzig 5. VR Hardware und Software für den medizinischen Einsatz 6. Evaluation 7. Fazit und Ausblick 8. Literaturverzeichnis 9. Online-Quellen Anhang A) Projektstrukturplan B) Zeitplan C) Poster D) Evaluationsprotokolle