Organizational Unit:
Daniel Guggenheim School of Aerospace Engineering

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Now showing 1 - 3 of 3
  • Item
    Testing the effects of violating component axioms in validation of complex aircraft systems
    (Georgia Institute of Technology, 2014-12-08) Kansal, Aparna
    This thesis focuses on estimating faults in complex large-scale integrated aircraft systems, especially where they interact with, and control, the aircraft dynamics. A general assumption considered in the reliability of such systems is that any component level fault will be monitored, detected and corrected by some fault management capability. However, a reliance on fault management assumes not only that it can detect and manage all faults, but also that it can do so in sufficient time to recover from any deviation in the aircraft dynamics and flight path. Testing for system-level effects is important to ensure better reliability of aircraft systems. However, with existing methods for validation of complex aircraft systems, it is difficult and impractical to set up a finite test suite to enable testing and integration of all the components of a complex system. The difficulty lies in the cost of modelling every aspect of every component given the large number of test cases required for sufficient coverage. Just having a good simulator, or increasing the number of test cases is not sufficient; it is also important to know which simulation runs to conduct. For this purpose, the thesis proposes simulating faults in the system through the violation of “axiomatic conditions” of the system components, which are conditions on the functioning of these components introduced during their development. The thesis studies the effect, on the aircraft dynamics, of simulating such faults when reference models of the components representing their key functions are integrated.
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    Developing a computational model of the pilot's best possible expectation of aircraft state given vestibular and visual cues
    (Georgia Institute of Technology, 2014-12-05) Onur, Can
    Loss of Control (LOC) accidents are a major threat for aviation, and contribute the highest risk for fatalities in all aviation accidents. The major contributor to LOC accidents is pilot spatial disorientation (SD), which accounts for roughly 32% of all LOC accidents. A pilot experiences SD during flight when the pilot's expectation of the aircraft's state deviates from reality. This deviation results from a number of underlying mechanisms, such as distraction, failure to monitor flight instruments, and vestibular illusions. Previous researchers have developed computational models to understand those mechanisms. However, these models are limited in scope as they do not model the pilot's knowledge of the aircraft dynamics. This research proposes a novel model to predict the best-possible-pilot-expectation of the aircraft state given vestibular and visual cues. The proposed model uses a Model-Based Observer (MBO) as the infrastructure needed to establish an “expert pilot”. Expert pilots are known to form an internal model of the operated system through training and experience, which allows the expert to generate better internal expectations of the system states. Pilots' internal expectations are enhanced by the presence of information fed through the pilots̕ sensory systems. Thus, the proposed model integrates pilot's knowledge of the system dynamics (i.e. an aircraft model) with a continuous vestibular sensory model and a discrete visual-sampling sensory model. The computational model serves to investigate the underlying mechanisms of SD during flight and provide a quantitative analysis tool to support flight deck and countermeasure designs.
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    Preparing students to incorporate stakeholder requirements in aerospace vehicle design
    (Georgia Institute of Technology, 2014-04-04) Coso, Alexandra Emelina
    The design of an aerospace vehicle system is a complex integration process driven by technological developments, stakeholder and mission needs, cost, and schedule. The vehicle then operates in an equally complex context, dependent on many aspects of the environment, the performance of stakeholders and the quality of the design itself. Satisfying the needs of all stakeholders is a complicated challenge for designers and engineers, and stakeholder requirements are, at times, neglected in design decisions. Thus, it is critical to examine how to better incorporate stakeholder requirements earlier and throughout the design process. The intent of this research is to (1) examine how stakeholder considerations are currently integrated into aerospace vehicle design practice and curricula, (2) design empirically-informed and theoretically-grounded educational interventions for an aerospace design capstone course, and (3) isolate the characteristics of the interventions and learning environment which support students’ integration of stakeholder considerations. The first research phase identified how stakeholder considerations are taken into account within an aerospace vehicle design firm and in current aerospace engineering design curricula. Interviews with aerospace designers revealed six conditions at the group, interaction and individual levels affecting the integration of stakeholder considerations. Examining current curricula, aerospace design education relies on quantitative measures. Thus, many students are not introduced to stakeholder considerations that are challenging to quantify. In addition, at the start of an aerospace engineering senior design capstone course, students were found to have some understanding of the customer and a few contextual considerations, but in general students did not see the impact of the broader context or of stakeholders outside of the customer. The second research phase comprised the design and evaluation of a Requirements Lab and Stakeholders in Design Labs, two in-class interventions implemented in a senior aircraft design capstone course. Further, a Stakeholders in Design rubric was developed to evaluate students’ design understanding and integration of stakeholder considerations and, as such, can be used as a summative assessment tool. The two interventions were evaluated using a multi-level framework to examine student capstone design projects, a written evaluation, and observations of students’ design team meetings. The findings demonstrated an increase in students’ awareness of a diverse group of stakeholders, but also perceptions that students appeared to only integrate stakeholder considerations in cases where interactions with stakeholders were possible and the design requirements had an explicit stakeholder focus. Particular aspects of the aircraft design learning environment such as the lack of explicit stakeholder requirements, the differences between the learning environment in the two semesters of the course, and the availability of tools impacted students’ integration of stakeholder considerations and overall effectiveness of the interventions. This research serves as a starting point for future research in pedagogical techniques and assessment methods for integrating stakeholder requirements into technology-focused design capstone courses. The results can also inform the vehicle design education of students and engineers from other disciplines.