Date of Award

4-2019

Degree Name

Master of Science

Department

Mechanical and Aerospace Engineering

First Advisor

Dr. Kapseong Ro

Second Advisor

Dr. Richard Meyer

Third Advisor

Dr. Jennifer Hudson

Fourth Advisor

Dr. Peter Gustafson

Access Setting

Masters Thesis-Open Access

Abstract

This thesis documents a conventional and modern flight control system design process carried out on a tailless aircraft Simulink model with innovative control effectors provided by Lockheed Martin. To set scope and design requirements a performance analysis was carried out to categorize the aircraft. Evaluation of open-loop dynamics reveled modal instabilities as well as state and control coupling. Flight condition dependent pole migration mapping reveled large changes in the aircraft’s static stability. Leading to the development of a four channel proportional-integral- derivative (PID) stability and control augmentation system (SCAS) controlling pitch-rate, roll-rate, side-slip angle, and airspeed states. PID gains are scheduled via iterative constrained optimization throughout the linearized flight envelope generating a full flight envelope flight control system. The linear quadratic (LQ) servo design method provides optimal control allocation at every linearized flight condition, controlling angle of attack, roll angle, side-slip angle, and airspeed states. LQ controlled states were modified to be equivalent to the PID control system for real time handling qualities (HQ) evaluation. Both control systems required gain scaling to prevent state resonance and control saturation during nonlinear 6-degree-of-freedom (6DOF) real-time simulation. Either method achieved stable augmented control of the innovative control effectors (ICE) aircraft throughout the flight envelope. The HQ’s for the control methods are satisfactory for conventional aerobatics but became dissimilar for sustained super-maneuverability flight conditions.

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