Date of Award

1-1-2012

Document Type

Thesis

Degree Name

M.S.

Department

Mechanical Engineering

First Advisor

Rahmat Shoureshi

Keywords

Aircraft structural health monitoring, Computational Fluid Dynamics (CFD), Feature-based diagnostics, Global diagnostics, Neural network, Neuro-symbolic network

Abstract

Engineered system diagnostics have been researched over the years with many successful results. From transportation systems to office technologies, many have been equipped with self-diagnostic capabilities and are called Smart Machines. In spite of these advances, current diagnostic systems are driven by direct sensory information without much concern for patterns of the system behavior or features associated with them. For large-scale systems with complex dynamics, global as well as local diagnostics become of great importance, where sensory information is used as input for the local diagnostics, and patterns of behavior or features are utilized for global diagnostics.

The main objective of this research is to develop a bio-inspired data/information architecture for feature-based global diagnostics of a large-scale system. In order to accomplish this goal, information from local diagnostic systems is integrated with physical and engineering principles (e.g. conservation of momentum) to create a feature-based neuro-symbolic network. This network is very similar to a neural network, except that it is based on a physical equation, and it uses features instead of raw data. Results from this network identify patterns of behavior that display whether the system has any faulty states. The architecture of this network includes two feature-based neuro-symbolic networks, one for the x-axis and one for the z-axis. Each of these networks has four inputs and four outputs, and includes one hidden layer.

In order to verify performance of this feature-based diagnostic system, a working aircraft model has been equipped with pressure sensors on its wing surface, and data has been taken during flight. By using computational fluid dynamic analysis, pressure contours along the wing have been developed. These pressure patterns have been used as input for our developed feature-based neuro-symbolic networks to predict the state of the model aircraft in real-time. Based on these research results, we have developed a neuro-symbolic diagnostic technique which can be applied to fault detection of large-scale systems, using local diagnostic information.

Provenance

Recieved from ProQuest

Rights holder

Tracy Lynn Schantz

File size

116 p.

File format

application/pdf

Language

en

Discipline

Mechanical engineering, Artificial intelligence

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