Abstract
This study aimed to analyze the effect that center of gravity (CG) variations have on an aircraft’s autopilot system. A low-fidelity model of the aircraft’s roll dynamics under various weapons payload distributions was derived and linear quadratic control (LQR) was used to regulate the roll angle and roll rate. Controllers were designed for both the unloaded and fully loaded aircraft, and tested on the unloaded, half loaded, and fully loaded configurations. Simulation of the low-fidelity model showed that the variations in mass and CG locations had negligible effect on the designed controllers for a typical combat aircraft.