31-40 of 204 results
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Novel Space Science Test via Adaptive Control and Integral Concurrent Learning Leveraging On-Orbit CubeSat Structural Identification
PI Riccardo Bevilacqua
The objective of this work is to create the basic science underpinning the structural testing and evaluation framework and control for deployable large spacecraft.
The objective of this work is to create the basic science underpinning the structural testing and evaluation framework and control for deployable large spacecraft. Large space structures and those with high dimensional ratio between deployed and stowed configurations are extremely difficult to test on the ground. The AFRL’s Space Vehicle Directorate recently opened the new Deployable Structures Laboratory, or DeSeL, as evidence of a renewed interest towards these systems. DeSeL represents the state-of-the-art technology for on-the-ground experimentation of deployable systems. In particular, an active Gravity Off-Load Follower (GOLF) cart system is being currently developed, intended to have three degrees of freedom (attitude motion) which could foreseeably provide the capability for large low-frequency motions. The real capabilities of the GOLF system are yet to be determined, and this research effort will develop in parallel, assist, support and inform the development of this new facility at AFRL.
New testing and evaluation science to identify these systems’ behavior and control them, that are robust to large uncertainties in the structural dynamics are then needed, and the first time they deploy on orbit is the ultimate test.
We propose to obtain the objective by combining novel control and learning theory with ad-hoc experimental activities. The culmination of this effort will be a flight demonstration, where a CubeSat previously designed by the Advanced Autonomous Multiple Spacecraft (ADAMUS) laboratory will be modified in its design and perform autonomous on-orbit structural identification, control, and testing.
The flight demonstration will be based on measuring the natural frequencies, damping ratios and vibration mode shapes via excitation of the spacecraft, using reaction wheels on the main hub and potentially distributed small thrusters on the flexible bodies, emulating the configuration of the AFRL’s Space Solar Power Incremental Demonstrations and Research Project (SSPIDR).
Categories: Faculty-Staff
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GNC Efforts in Support of the University of Floridas Research for the NASA Instrument Incubator
PI Riccardo Bevilacqua
The following tasks will be performed by one Ph.D. student and Dr. Bevilacqua (PI at ERAU), in support of the University of Florida’s proposal for the NASA’s Instrument Incubator Program (IIP):
Year 1:
- Drag-compensation and test mass control design. Adaptive control combined with integral concurrent learning will be investigated to estimate, in real-time, the effects of drag on the spacecraft, to enable precise control of the test mass inside it. The PI has successfully used this technique for drag-based spacecraft formation flight, where online estimation of the ballistic coefficient of an unknown vehicle is critical.
- Support for drag-compensation thruster mapping. Lyapunov-based thruster selection principles, previously developed by the PI, will be used to simplify the thruster mapping problem, and prevent the use of any numerical iterations, to ease online implementation. An additional step will involve exploring the possibility to use adaptive + ICL control to also estimate the thrust errors and their misalignment.
Year 2:
- Spacecraft acceleration estimation based on S-GRS outputs. The test mass position and orientation are measured inside the sensor and the applied forces and torques on the test mass are known. How to use this information to optimally estimate the spacecraft acceleration and angular acceleration due to atmospheric drag remains a challenge. An approach based on a bank of Kalman (or Extended Kalman) Filters will be explored, possibly in iterative form, as previously done for spacecraft relative motion estimation by Dr. Gurfil at Technion and by the PI and one of his former students.
Year 3:
- Support for hardware-in-the-loop testing of the control system at UF. The PI and the PhD student will support experimentation at UF, to implement the above algorithms in hardware systems. The PI has over a decade of experience in on-the-ground testing of spacecraft GNC systems.
Year 1-3:
- Support for numerical simulation of the closed-loop system. High-fidelity orbital and attitude propagators will be used to test the algorithms developed. STK and NASA’s Spice will also be candidates for comparison.
Categories: Faculty-Staff
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CubeSats Hosting Flexible Appendages for On-Orbit Testing of Advanced Control Algorithms
PI Riccardo Bevilacqua
The objective of this work is to start the assembly of a CubeSat hosting specialized flexible appendages, taking inspiration from a previously designed spacecraft developed by the Advanced Autonomous Multiple Spacecraft (ADAMUS).
The objective of this work is to start the assembly of a CubeSat hosting specialized flexible appendages, taking inspiration from a previously designed spacecraft developed by the Advanced Autonomous Multiple Spacecraft (ADAMUS). This CubeSat will eventually enable testing of ADAMUS’ developed spacecraft control algorithms on-orbit.
Relevance to NASA: The innovation proposed herein lies in the ability to autonomously characterize and control complex space structures. This project will directly support NASA’s TA 4: Robotics and Autonomous Systems
Categories: Faculty-Staff
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A Machine Learning Based Transfer to Predict Warhead In-Flight Behavior from Static Arena Test Data
PI Riccardo Bevilacqua
The objective of this work is to combine high-fidelity numerical models with unique/ad-hoc experimental activities to strengthen basic science underpinning the test and evaluation framework for warhead fragmentation and fragments fly-out.
Warhead fragmentation predictions are based on either numerical simulations or static arena tests where detonations occur in unrealistic conditions (not flying). The first methodology presents many shortcomings: there is no agreement on the state of the art for simulations, and many tools ignore important aspects such as gravity, aerodynamic forces and moments, and rigid body motion of different shape fragments. Numerical simulations are also lengthy and cannot be used as online/on-the-battlefield tools. The experimental approach is also extremely limited, as it does not reproduce the real-world conditions of a moving warhead.
The objective of this work is to combine high-fidelity numerical models with unique/ad-hoc experimental activities to strengthen basic science underpinning the test and evaluation framework for warhead fragmentation and fragments fly-out. In particular, we will aim at combining the most advanced simulation capabilities with static experimental data, to obtain a transfer function predicting lethality and collateral damage of a given warhead in real-life conditions. Artificial neural networks and/or other machine learning tools (e.g., Random Forests) will be used to capture the underlying physics governing fragments dispersion under dynamic conditions, coming from NAVAIR’s Spidy software, and eventually combine this knowledge with real warhead characteristics, coming from the static test. This proposal is of high impact because of the existing gap in analytical tools to define and validate warhead fragmentation testing.
The broader impact (long term) of this work may be a software tool that the warfighter can use on the field to rapidly assess the effects of the arsenal at his disposal. This tool will be equally beneficial to designers and testers within the Air Force and the DoD in general.
Categories: Faculty-Staff
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Evaluating Preflight Weather Briefing Strategies
PI Elizabeth Blickensderfer
CO-I Thomas Guinn
CO-I Robert Thomas
The objective of this grant is to examine General Aviation (GA) pilots’ capability to conduct Preflight Weather self-briefings as compared to using Flight Services to obtain weather briefings. Previous research indicates that GA pilots are increasingly conducting weather self-briefings during preflight (Duke et al., 2019). Additional research indicates that GA pilots have moderately low performance when interpreting aviation weather observation and forecast products (Blickensderfer et al., 2019). Research is needed to assess and understand the attitudes, knowledge, and performance of GA pilots conducting self-briefings to identify possible gaps and, in turn, provide recommendations for future system design and pilot training.
Categories: Faculty-Staff
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STEM Literacy and Service-Learning
PI Sally Blomstrom
This service-learning project investigates STEM literacy and involves students in sections of Speech (COM 219). Students create an audio tour about a specimen from the A. Jewell Schock Natural History Museum. The audio tour includes the specimen’s scientific name, a description of its biology, its habitat, its diet, and the forces of flight related to the specimen as well as its biomechanics.
They will be instructed to develop content which includes descriptive information about the biology of the specimen (science), the biomechanics used (engineering), dimensions of the specimen and its rate of speed (math). They will use technology in the process of creating and sending the audio files, and the museum will use technology to make the files available to visitors of the museum, both online and in person (technology). The goal is to have students engage in research on a STEM topic and then communicate their knowledge to a general audience using technology. We are investigating if, and to what extent, the project increases STEM literacy which is defined as a demonstrated ability to read STEM text, tables, and graphics with understanding, to evaluate the quality of the read information, to identify relevant information and incorporate that information in written or oral communication.
Categories: Faculty-Staff
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Humanistic STEM: Blending Humanities and STEM to Increase Undergraduate Student Engagement, Knowledge, and Skills
PI Debra Bourdeau
NSF IUSE #2120807
Categories: Faculty-Staff
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Developing Autonomous, Targeted Feedback in Precalculus
PI Darryl Chamberlain
The overriding goal of this project is to investigate student knowledge in a Precalculus course at ERAU-W in order to construct autonomous, targeted feedback for free-responses questions to enhance students' online learning. This will be accomplished by analyzing student responses to exam questions and interviewing students to probe how their mathematical conceptions correspond to their exam responses.
Categories: Faculty-Staff
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A Boltzmann Simulator for Porous Media Flows
PI Leitao Chen
This project develops numerical simulations through parallel development of a Boltzmann model to capture and elucidate multiscale thermos-fluids behaviors in porous media, as well as the fluid-solid interactions.
To accurately simulate porous media flow problem, a kinetic model based on the Boltzmann equation (BE) was developed. Two primary reasons justified the choice of a BE-based approach over conventional Navier-Stokes (N-S) computational fluid dynamics (CFD) methods. First, the fluid flow within porous media often occurs in extremely narrow channels, representing high-Knudsen-number flow regimes. The Knudsen number (Kn), defined as the ratio of molecular mean free path to the smallest channel dimension, indicates that traditional N-S equations are physically inadequate for accurately describing these flow conditions. Conversely, BE-based models are well-established to yield physically accurate results for high-Kn flows. Second, from a computational standpoint, the BE inherently involves a simpler mathematical structure due to its linear advection term, substantially reducing computational overhead compared to the nonlinear N-S equations. This simplification significantly improves computational efficiency, especially critical for simulating flow within complex porous structures. To better capture the complex boundaries in porous media, a meshless discretization method of the BE has been developed in this project. This meshless approach entirely eliminates dependency on mesh generation, offering significant advantages in accurately simulating flow through porous media.Categories: Faculty-Staff
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Project Global Officer
PI Aaron Clevenger
Project GO provide's overseas language instruction consisting of a minimum of 8 weeks and/or 150 contact hours (per grant program) to ROTC students nationwide with the goal of helping student to reach an ILR 1 proficiency level in a critical language: Mandarin Chinese in Taiwan, and Arabic in Jordan. All students should reach the objective of successfully applying the target language and cultural knowledge in actual communication with native speakers.
Categories: Faculty-Staff
31-40 of 204 results