Browsing by Author "Dr. Sharon Lubkin, Committee Member"

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    Analysis of Taxi Test Data for an Unmanned Aerial VehicleImplemented with Fluidic Flow Control
    (2006-07-07) Turner, Drew Patrick; Dr. Sharon Lubkin, Committee Member; Dr. Ashok Gopalarathnam, Committee Member; Dr. Charles E. Hall, Jr., Committee Chair
    Serpentine inlet ducts are utilized in many aircraft where the inlet capture area is located off the thrust line or there is a desire to conceal the engine compressor face. Due to the curvature that characterizes a compact serpentine duct, issues with flow distortion and total pressure loss at the engine face arise leading to reduction in propulsion system performance. Computational analysis has shown that flow control implementing micro-fluidic vortex generators significantly reduces the losses. Previous work at North Carolina State University has demonstrated the benefits of a fluidic flow control of this type in a highly compact serpentine inlet duct through the design and experimental static testing of a propulsion system for an uninhabited aerial vehicle. With the implementation of flow control, engine face distortion was reduced and propulsion system performance was increased. This work continues the investigation of the effectiveness of the fluidic flow control by examining the performance of the system during dynamic situations through high speed taxi testing of an uninhabited aerial vehicle implemented with this technology. Additionally, the collected data was used to compare calculated takeoff parameters to values calculated using standard takeoff analysis.
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    Design Study of an Autonomous Unmanned Air Vehicle Controller
    (2005-12-06) Peterson, Joseph Scott; Dr. Sharon Lubkin, Committee Member; Dr. Fen Wu, Committee Member; Dr. Charles Hall, Committee Chair
    The purpose of this document is to both quantitatively and qualitatively compare three varying approaches to control of unmanned air vehicles: dynamic inversion, classical gain scheduling, and robust gain scheduling through H∞ synthesis. The quantitative comparisons include robust performance and robust stability measures of the aircraft and controller linearized about a trim operating point. A second study will look at the time response of the system with varying perturbation to the nominal plant dynamics. The qualitative analysis looks at the complexity of the controller and time required to implement, this included comparison of iterative solving methods for system gains both in the frequency and time domains. A full nonlinear form of the dynamic inversion controller was implemented with full non-linear simulation in Simulink and shows comparable results to the linearized studies. The results have shown that a dual loop controller with a dynamic inversion inner loop and H∞ outer loop has the largest robust performance over the flight envelope but one of the more advanced forms of control for implementation.