Peter Heidlauf, Matthew Cooper
Air Force Institute of Technology, USA
Title: Nonlinear Lyapunov control improved by an extended least squares adaptive feed forward controller and enhanced Luenberger observer
Biography
Biography: Peter Heidlauf, Matthew Cooper
Abstract
Three adaptive approaches for a non-linear feedforward controller are combined with and sinusoidal trajectory planners in a
spacecraft attitude control system. Physics-based feedforward control, trajectory generation, observers, feedback control, and
system stability are discussed in relation to the nonlinear dynamics under simulation. The adaptive feedforward controllers compared
include an adaptive controller, a Recursive Least Square (RLS) Method, and an Extended Least Squares (ELS) Method. A novel
approach to incorporate ELS in adapting an idealized feedforward controller was developed and compared to the standard RLS
optimal estimator. For a large slew maneuver, the controller configuration with ELS feedforward, PID feedback, and sinusoidal
trajectory outperformed the baseline adaptive controller. Mean error was decreased by 23.4%, error standard deviation by 34.0%, and
maximum error by 33.0%. Mean control effort was similar for all controller configurations. This improvement is due to corrections
for miss-modeled dynamics, which occur during spacecraft launch, collisions with debris, or due to fuel slosh and loose components