Six-DOF Trajectory Tracking for Payload Directed Flight Using Trajectory Linearization Control Tony M. Adami 1 and J. Jim. Zhu 2 Avionics Engineering Center, Ohio University, Athens, OH 45701 Abraham K. Ishihara 3 , Yoo-Hsiu Yeh 4 Carnegie Mellon University Silicon Valley Campus, Moffett Field, CA, 94035 Corey A. Ippolito 5 NASA Ames Research Center, Moffett Field, CA 94035 Payload Directed Flight (PDF) calls for agile and precise tracking control of an air vehicle that poses significant challenges to current flight control techniques. To support the goals of NASA’s Payload Directed Flight program, Trajectory Linearization Control (TLC) can provide robust, agile tracking of online-generated near-optimal trajectories for a wide variety of applications. In this paper we describe a 6DOF tracking controller design for a generic general aviation (GA) aircraft dynamics model using TLC. Initial design verification is presented via simulation results. Nomenclature [ ] T E E E P x y z = = sensed inertial position vector [ ] T E E E P x y z = = nominal inertial position vector com ,com ,com ,com T E E E P x y z ⎡ ⎤ = ⎣ ⎦ = commanded inertial position vector [ ] T V u v w = = sensed body velocity vector [ ] T V u v w = = nominal body velocity vector [ ] com com com com T V u v w = = commanded body velocity vector b T x y z F F F F ⎡ ⎤ = ⎣ ⎦ = sensed total body force vector b T x y z F F F F ⎡ ⎤ = ⎣ ⎦ = nominal total body force command vector b,ctrl ,ctrl ,ctrl ,ctrl T x y z F F F F ⎡ ⎤ = ⎣ ⎦ = feedback control force command vector [ ] ab T F X Y Z = = aerodynamic force vector in the body frame aw a a a T x y z F F F F ⎡ ⎤ = ⎣ ⎦ = aerodynamic force vector in the wind frame , , DCL = drag, side, and lift force vectors [ ] T φ θ ψ Γ= = sensed Euler angles (Earth-Centered, Earth-Fixed - ECEF) T φ θ ψ ⎡ ⎤ Γ= ⎣ ⎦ = nominal Euler angles (ECEF) 1 Research Engineer, Ohio University Avionics Engineering, Athens, OH, AIAA Student Member 2 Professor, Ohio University School of Electrical Engineering and Computer Science, Athens, OH, AIAA Member 3 Research Scientist, Carnegie Melon University West, AIAA Member 4 Project Engineer, Intelligent Systems Division, NASA Ames Research Center, AIAA Member 5 Research Scientist, Intelligent Systems Division, NASA Ames Research Center, AIAA Member AIAA Infotech@Aerospace Conference <br>and <br>AIAA Unmanned...Unlimited Conference 6 - 9 April 2009, Seattle, Washington AIAA 2009-1897 Copyright © 2009 by J. Jim Zhu. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.