Feedback linearization guidance for approach and landing of reusable launch vehicles

A feedback linearization guidance system is developed for approach and landing of a reusable launch vehicle. The three-input three-output system is derived through a state transformation using Lie algebra, resulting in a five state linear system. The linearization is shown to be valid for headings within ninety degrees of runway heading and flight path angles within ninety degrees of horizontal. A pseudo control is designed based on a linear quadratic tracker with integrators. Lie algebra then gives the transformation from pseudo control to physical control. An approximate aerodynamic model gives a further transformation from lift, drag, and bank angle, to negative z axis acceleration, bank angle, and speed brake position. The controller is simulated in a Matlab / Simulink environment, and certain controller parameters are optimized using a genetic algorithm.