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This thesis aims to evaluate how different mixed reality solutions can be built and whetheror not it could be used for flight simulators. A simulator prototype was implemented usingUnreal Engine 4 with Varjo’s Unreal Engine plugin giving the foundation for the evaluations done through user studies. Three user studies were performed to test subjectivelatency with Varjo XR-1 in a mixed reality environment, test hand-eye coordination withVarjo XR-1 in a video see-through environment, and test the sense of immersion betweenan IR depth sensor and chroma key flight simulator prototype. The evaluation was seenfrom several perspectives, consisting of: an evaluation from a latency perspective on howa mixed reality solution would compare to an existing dome projector solution, how wellthe masking could be done when using either chroma keying or IR depth sensors, andlastly, which of the two evaluated mixed reality techniques are preferred to use in a senseof immersion and usability.The investigation conducted during the thesis showed that while using a mixed realityenvironment had a minimal impact on system latency compared to using a monitor setup.However, the precision in hand-eye coordination while using VST-mode was evaluated tohave a decreased interaction accuracy while conducting tasks. The comparison betweenthe two mixed reality techniques presented in which areas the techniques excel and wherethey are lacking, therefore, a decision needs to be made to what is more important for eachindividual use case while developing a mixed reality simulator.

Nowadays surgery simulations are aiming to apply not just visual effects but forcefeedback as well. To carry out force feedback, haptic devices are utilized that are mostlycommercial products for general purposes. Some of the haptic device features are moreimportant than others in case of surgery simulator use. The precision of the output forcemagnitude is one such property. The specifications provided by haptic devicemanufacturers are lacking details on device characteristics, known to cause difficulties inplanning of accurate surgery simulations.This project shows the design of a testbed that is capable of measuring the precision ofoutput forces within the haptic devices’ workspace. With the testbed, a set ofmeasurements can be run on different haptic devices, giving as a result a betterknowledge of the utilized device. This knowledge aids the design of more precise andrealistic surgery simulations.

This research developed the quasi-static and dynamic equipment and protocols for tests of both Very-High-Strength Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC) to predict blast performance. VHSC was developed for high compressive strength (> 200 MPa). Using VHSC as the baseline material, HSHDC was developed and exhibits comparable compressive strength (> 150 MPa) and high tensile ductility (> 3% tensile strain). This research investigated quasi-static material properties including compression, tension, and flexure (third-point and pressure loadings). Additionally, dynamic blast load simulator (shock tube) tests were performed on simply-supported one-way panels in flexure. Subsequently, the material response in flexure was predicted using the Wall Analysis Code (WAC). Although VHSC has a higher peak flexural strength capacity, HSHDC exhibits higher ductility through multiple parallel micro-cracks transverse to loading. The equipment and test protocols proved to be successful in providing ways to test scaled concrete specimens quasi-statically and dynamically.

Shipboard Power Systems (SPS) play a significant role in next-generation Navy fleets. With the increasing power demand from propulsion loads, ship service loads, weaponry systems and mission systems, a stable and reliable SPS is critical to support different aspects of ship operation. It also becomes the technology-enabler to improve ship economy, efficiency, reliability, and survivability. Moreover, it is important to improve the reliability and robustness of the SPS while working under different operating conditions to ensure safe and satisfactory operation of the system. This dissertation aims to introduce novel and effective approaches to respond to different types of possible faults in the SPS. According to the type and duration, the possible faults in the Medium Voltage DC (MVDC) SPS have been divided into two main categories: transient and permanent faults. First, in order to manage permanent faults in MVDC SPS, a novel real-time reconfiguration strategy has been proposed. Onboard postault reconfiguration aims to ensure the maximum power/service delivery to the system loads following a fault. This study aims to implement an intelligent real-time reconfiguration algorithm in the RTDS platform through an optimization technique implemented inside the Real-Time Digital Simulator (RTDS). The simulation results demonstrate the effectiveness of the proposed real-time approach to reconfigure the system under different fault situations. Second, a novel approach to mitigate the effect of the unsymmetrical transient AC faults in the MVDC SPS has been proposed. In this dissertation, the application of combined Static Synchronous Compensator (STATCOM)-Super Conducting Fault Current Limiter (SFCL) to improve the stability of the MVDC SPS during transient faults has been investigated. A Fluid Genetic Algorithm (FGA) optimization algorithm is introduced to design the STATCOM's controller. Moreover, a multi-objective optimization problem has been formulated to find the optimal size of SFCL's impedance. In the proposed scheme, STATCOM can assist the SFCL to keep the vital load terminal voltage close to the normal state in an economic sense. The proposed technique provides an acceptable post-disturbance and postault performance to recover the system to its normal situation over the other alternatives.

Self-motion perception is based on the integration of visual (optic flow) and vestibular (inertial) sensory information. Previous research has shown that the relative contribution of visual and vestibular cues can change in real time based on the reliability of that information. The present study assessed whether initial velocity and acceleration magnitude influence the relative contribution of these cues to the detection of self-acceleration. Participants performed a simple response time task with visual and vestibular self-acceleration cues as targets. Visual optic flow was presented at three possible initial velocities of 3, 9, or 15 m/s, and accelerated to result in three possible final velocities of 21, 27, or 33 m/s. Corresponding vestibular cues were presented at magnitudes between 0.01 and 0.04 g. The self-acceleration cues were presented at three possible stimulus onset asynchronies (SOAs): visual-first (by 100 ms), in-sync, and vestibular-first (by 100 ms). We found that presenting the cues in-sync resulted in the fastest responses across all velocities and acceleration magnitudes. Interestingly, presenting the visual cue first resulted in a relative advantage over vestibular-first at the slowest initial velocity of 3 m/s, and vice versa for the fastest initial velocity of 15 m/s. The fastest overall responses for visual-first and in-sync were observed at 9 m/s. The present results support the hypothesis that velocity of optic flow can alter the relative contribution of visual and vestibular cues to the detection of self-acceleration. / Thesis / Master of Science (MSc) / This thesis contributes valuable insight into the emerging literature on how visual and vestibular cues are integrated to result in reliable self-motion perception. Specifically, this thesis provides evidence that velocity of optic flow plays an important role in mediating the relative weighting of visual and vestibular cues during acceleration perception.

This master thesis project aims to complete and verify core functions of a test rig that is designed and built to emulate drive cycles for measuring the energy consumption of HEVs, especially a vehicle named ELBA from KTH Integrated Transport Research Lab (ITRL). To fulfill this goal, a simplified model is created for the test rig, whose involved parameters are identified through various experiments. Then the model is verified by both step voltage responses and sinusoidal current responses. Meanwhile, vehicle dynamics is modeled to calculate required resistance force for road slope emulation. Moreover, an existing method, vehicle equivalent mass, is utilized to compensate dynamic force of the vehicle body, enabling simulation of regenerative braking without an extra flywheel. Together with test rig’s model that is responsible for converting required resistance force to demanded current reference, the rig’s functions are completed and ready for final verification. As a result, the driver of the DC motor on the rig is found to has lower current limitation than required so that the rig is not able to entirely compensate dynamic force of the car. However, the feasibility of the principle is still proved by the tests. Based on the result, recommendations are given to solve the problem and achieve other improvements in the future. / Detta examensarbete syftar till att slutföra och verifiera kärnfunktioner i en testrigg som är designad och byggd för att emulera körcykler för att mäta energiförbrukningen för elhybridbilar, särskilt ett fordon som heter ELBA från KTH Integrated Transport Research Lab (ITRL). För att uppfylla detta mål skapades en förenklad modell för testriggen, vars parametrar identifieras genom olika experiment. Sedan verifieras modellen av både stegspänningssvar och sinusformade strömsvar. Under tiden modelleras fordonsdynamiken för att beräkna erforderlig motståndskraft för väglöpemulering. Samtidigt modelleras fordonsdynamiken för att beräkna den erforderliga motståndskraften för emulering av väglutningar. Dessutom används en befintlig metod, fordonsekvivalentmassa, för att kompensera fordonskroppens dynamiska kraft, vilket möjliggör simulering av regenerativ bromsning utan extra svänghjul. Tillsammans med testriggens modell som är ansvarig för att konvertera erforderlig motståndskraft till efterfrågad strömreferens, är riggens funktioner färdig och redo för slutlig verifiering. Som ett resultat har föraren av likström motorn på riggen visat sig ha lägre strömbegränsning än vad som krävs så att riggen inte helt kan kompensera bilens dynamiska kraft. Emellertid bevisas principens genomförbarhet fortfarande av testerna. Baserat på resultatet ges rekommendationer för att lösa problemet och uppnå andra förbättringar i framtiden.

An advanced training program on risk perception was developed and evaluated in a driving simulator. This training program included two elements. The first one was a PC-based Risk Awareness and Perception Program (RAPT) that had been developed and evaluated in several studies by researches at the Human Performance Lab within the last several years. Plan views of risky scenarios were used to explain to participants the location of potential hazards. The second element of the training (SIMRAPT) was newly developed for this study and used the portable low-cost driving simulator Drive Square Simulation System to train risk perception skills while the participant actually drove a real car in a virtual environment. A head mounted display was used to present the virtual world. Feedback was given to participants when they failed to scan appropriately for hazards. Twelve novice drivers served as experimental group and were trained with the combined RAPT/SIMRAPT training program. Twelve other novice drivers were given training not relevant to hazard anticipation and served as the control group. After training, both groups were evaluated on an advanced driving simulator (different from the Drive Square Simulation System used in SIMRAPT training) and the eye movements of both groups of drivers were measured. The drivers’ score was based on whether or not their eye-fixations indicated recognition of potential risks in different driving situations. The evaluation included eight scenarios used in the RAPT/SIMRAPT training (near transfer scenarios) and eight scenarios that were not used in the training (far transfer scenarios). The results indicated that trained drivers are more likely than untrained drivers to fixate on regions where potential risks might appear. Further the evaluation indicates that the training effect of the combined training using both the PC (RAPT) and a low-cost driving simulator (SIMRAPT) is larger than for training programs that only use the PC, though not significantly so.

Roadside vegetation provides numerous environmental and psychological benefits to drivers. Previous studies have shown that natural landscapes can effectively lower crash rates and cause less stress and frustration to the driver. However, run-off-the-road crashes resulting in a collision with a tree are twice as likely to result in a fatality, thus reinforcing the need to examine the placement of vegetation within the clear zone. This study explores the relationship between the size of the clear zone and the presence of roadside vegetation on selected driver attributes, including both driver speed and lateral positioning. To evaluate the effect on the driver speed selection process, a static evaluation was employed. Completed by more than 100 drivers, the static evaluation was utilized to gather speed selections on both real and virtual roads containing four combinations of clear zone size and roadside vegetation density. Additionally, field data was collected to validate the findings of the static evaluation and to determine the extent to which roadside vegetation impacts driving attributes. When presented with a large clear zone, drivers positioned the vehicle further from the edge of the road as the vegetation density increased. Furthermore, the speeds observed in the field correlated with the speeds that participants selected when watching a video of the same road. Finally, the UMassSafe Traffic Safety Data Warehouse was utilized to link crash and roadway data, allowing for an in-depth analysis of run-off-the-road (ROR) crash severity. The results of this study further demonstrate the nature of the relationship between clear zone design and driver behavior.