ADAPTIVE-CONTROL OF FEEDBACK LINEARIZABLE NONLINEAR-SYSTEMS WITH APPLICATION TO FLIGHT CONTROL

The question of output trajectory control of a class of input-output f eedback linearizable nonlinear dynamical systems using state variable feedback in the presence of parameter uncertainty is considered. For t he derivation of a control law, a hypersurface is chosen, which is a l inear function of the tracking error, its derivatives, and the integra l of the tracking error. An adaptive control law is derived such that in the closed-loop system the trajectory asymptotically converges to t his hypersurface. For any trajectory evolving on this surface, the tra cking error tends to zero. Based on these results, a new approach to t he design of an adaptive flight control system Is presented. In the cl osed-loop system, trajectory control of the sets of output variables r oll angle, angle of attack, and sideslip angle (phi, alpha, beta) and roll, pitch, and sideslip angles (phi, theta, beta) using aileron, rud der, and elevator control is presented. Simulation results are obtaine d to show that precise simultaneous longitudinal and lateral maneuvers can be performed in spite of large uncertainty in the aerodynamic par ameters.