Ultimate boundedness control of uncertain systems with application to roll coupled aircraft maneuver

The problem of robust trajectory control of a class of nonlinear systems which can be decoupled by state variable feedback is treated. It is assumed that the system matrices are unknown but bounded. A nonlinear control law is derived so that the tracking error in the closed-loop system is uniformly bounded and tends to a certain small neighborhood of the origin. The error dynamics are asymptotically decoupled in an approximate sense. The controller includes a reference trajectory generator and uses the integral feedback of the tracking error. Using this result, a flight control system is designed for the control of roll angle, angle of attack, and sideslip in rapid, nonlinear aircraft maneuvers. Simulation results are presented to show that large, simultaneous lateral and longitudinal maneuvers can be performed in spite of the uncertainty in the stability derivatives