AE Graduate Student Conference Papers

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    Holographic augmented reality visualization interface for exploration
    (Wichita State University, 2022-04-29) Bui, Bill; Hutton, Abbie; Adekalu, Oluwasayo; Hubener, Valerie; Zavala, P.; Hinshaw, Ramil; Karim, Radeef Ashhab Bin; Schoonover, Maggie; Smith, Kristyn; Patterson, Jeremy A.
    Based on Wichita's wheat harvesting nickname, Harvesters, Wichita State University NASA SUITS (Spacesuit User Interface Technologies for Students) team Harvestars proposed the integrated system H. A. R. V. I. E. (Holographic Augmented Reality Visualization Interface for Exploration) to prepare for the next Artemis moon landing. This design solution will assist astronauts with elevated demands of the lunar surface through navigation, terrain sensing, and an optimal display of suit status elements. Considering environmental constraints, the system architecture promotes efficient cross modal communication between the mission control center, other astronauts, and the user interface. Hands-free modality options are utilized such as gaze and speech recognition. To promote spatial learning, waypoint markers are displayed both in an allocentric world view map and egocentric first-person viewpoint. Spatial mapping, using depth sensing and 3D modeling, will read changes in displacement and elevation, and calculate the user's height to categorize hazardous objects. For pathfinding, our navigational system will create a directional arrow with the use of A* algorithm combined with spatial anchors. In the case of emergencies, distress beacons with color coded warning messages are displayed on navigational maps and displays. Throughout the design process, we conducted heuristic evaluations and Streamlined Cognitive Walkthroughs on a low fidelity prototype. Then, we implemented H.A.R.V.I.E into the HoloLens 2 and utilized the Rapid Iterative Testing & Evaluation method for human-in-the-loop testing. Our interface serves as a novel approach to enhance how astronauts navigate on missions using augmented reality. Final in-person testing will be conducted at NASA's Johnson Space Center.
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    Modified state observer for Solar Electric Propulsion Spacecraft
    (Wichita State University, 2021-04-02) Thulaseedharan Pillay, Yrithu; Steck, James E.; Dutta, Atri
    The use of Solar Electric Propulsion (SEP) for missions within the Earth-Luna system (cislunar) has been planned, due to its low propellent usage compared to chemical propulsion. However, SEP introduces much higher transfer times compared to the chemical propulsion systems, making optimal trajectory design and planning more challenging. This research explores the use of a real time (online) Neuroadaptive state observer, i.e., Modified State Observer (MSO) to improve the dynamic modeling that goes into the trajectory optimization. The MSO utilizes a single layer neural network to capture the unmodelled perturbations in the spacecraft dynamics, which could be caused by Earth's polar flattening (J2), Sun's radiation, and other forces. These can be incorporated into a multi-stage, receding horizons optimal controller to improve the trajectory planning and optimization. This is especially important in situations where the true dynamics are not modelled - due to lack of enough information or unknown dynamics, or the full or high-fidelity model cannot be used due to limitations in on-board computing power. The real-time adaptations could eliminate the need for offline training. The improved on-board tracking provided by the MSO could also eliminate a ground-in-loop control optimization, which would have communication delays in long distance travel. The MSO application was studied to ensure viability in a simple two-body problem scenario of a spacecraft orbiting the Earth in a circular orbit of altitude 100 km. A high-fidelity two-body model that incorporates the Earth's J2 perturbations was compared to a low-fidelity model without the J2 perturbations. The MSO was then incorporated into the low-fidelity model to adapt to the unmodelled perturbations. The resulting tracking errors in the MSO states were compared to the high-fidelity states. Position tracking errors of approximately 15 km and velocity tracking errors of approximately 0.015km/s were observed in the low-fidelity model, and observed to be increasing with time. The MSO improved these to 0.15 km and 0.004 km/s, respectively, showing that the MSO can model the unknown dynamics reliably. The effect of certain MSO tuning parameters - the observer gain, adaptation rate and neural network weight damping were also studied. Similar studies are currently being conducted on the three-body problem of a spacecraft moving in the Earth-Luna system. This uses a realistic high-fidelity model from the NASA General Mission Analysis Tool (GMAT) and a low-fidelity circular-restricted case, for various trajectories in the cislunar space.
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    Airframe usage analysis of C-130 aircraft used in aerial firefighting missions
    (Wichita State University, 2021-04-02) Ali, Syed Junaid; Kliment, Linda K.
    United States Forest Service (USFS) uses various types of aircraft to manage wildfires; these include helicopters, scoopers, single-engine airtankers (SEATs), large airtankers (LATs), and very large airtankers (VLATs). Among the LATs are two variants of C-130 aircraft, the EC- 130Q and L-382G. In this study, recorded flight data from two EC-130Q and two L-382G aircraft were analyzed to perform operational airframe usage assessment. These aircraft were flown in support of USFS aerial firefighting missions during 2016 through 2019 for a total of 1,354 flights, which accounted for approximately 882 hours of flight time. For analysis, flights were divided into two types; firefighting and ferry/maintenance flights. Aircraft usage information regarding maximum altitude, maximum indicated airspeed, and vertical load factors is presented and compared between the two types of flights. It was shown that the aircraft were largely flown within the operational limits. The aircraft analyzed in this study were modified to operate in an environment for which they were not originally designed. The ferry flights were most similar to those for which the aircraft were designed. A comparison was done between the ferry/maintenance and firefighting flights to show the differences in the airframe usage. Results of this study will help the operators determine how the current usage differs from that for which the aircraft was originally designed. Inspection and maintenance programs may then be adjusted in order to take the USFS usage into consideration.
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    Semi-tailless aircraft concept with variable cant stabilizers applied to small UAVs
    (Wichita State University, 2019-04-26) Hagen, Kevin; Miller, L. Scott
    In recent years the use of small UAVs (<5lbs) has grown rapidly. While fundamentally the same as large aircraft, differences in requirements, payloads, and cost allow for a greater number of viable concepts. Many new concepts have been proposed however, old concepts that were never adopted for large aircraft may be viable for small UAVs. One such concept is a semi-tailless concept proposed by Blohm & Voss in 1944. This concept placed the stabilizer surfaces outboard and aft of the wing tips of a highly swept main wing. This allowed for the removal of the empennage, resulting in a reduction of empty weight and wetted area, improving a number of performance parameters. Applying this concept to small UAVs mitigate some of the potential downsides, while providing additional opportunities. Specifically, varying the cant angle of the stabilizers to provide control and improve performance. Using the basic geometry developed by Blohm & Voss, trade studies were done to determine the effects of the stabilizer cant angle. A simple analytical model was used to perform trade studies and identify the key parameters affecting control. The configuration was then modeled with a vortex lattice solver to predict performance. Wind tunnel and flight testing was performed to validate predictions and provide pilot feedback on the aircraft's performance. It was found that the variable cant stabilizers do allow sufficient control for most of the flight regimes, and small increases in performance are possible. The results show that the concept is viable for application to small UAVs.
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    Laplace-based predictive estimation of loss-of-control boundaries on a transport aircraft
    (Wichita State University, 2017-04-28) Rajaram, Kiran; Rafi, Melvin; Steck, James E.; Chakravarthy, Animesh
    Loss-of-control events are the greatest contributing factor to accidents amongst commercial aircraft. In this research, an approach to predicting the onset of loss of-control events is developed using a Laplace-based method, where a state space model is used to simulate the dynamics of the aircraft. Laplace transformations are then used to calculate the control authority required to reach a predefined limit on the aircraft's angle-of-attack, where the limit represents the control loss boundary. This method is applied to the short period dynamics of the NASA Generic Transport Model, and the remaining amount of allowable control authority the pilot has before reaching a loss-of-control situation is then determined. This boundary is graphically presented through a three-dimensional display. Simulations are run within MATLAB/Simulink, and results demonstrate that the system is able to successfully predict the aircraft?s proximity to a control loss situation.
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