Adaptive control of aircraft lateral-directional axis using Subspace-Stabilization

A Linear Adaptive Control for the F-14 aircraft lateral-directional axis using disturbance-observers and Subspace-Stabilization Theory is presented. Disturbance accommodating observers are used to estimate and cancel out the combined effects of nonlinear, uncertain and off-nominal terms in real-time. Subspace Stabilization techniques are used to steer the system "error-state" to a certain subspace S representing the desired servo-tracking error behavior, while controlling the subsequent motion of the error-state on the subspace S to the origin. The results obtained are compared with previous results obtained using gain scheduling and H,. Numerical simulation results demonstrate that the ideal closed-loop responses of the rolling rate and sideslip angle are adequately tracked, and that the controller effectively decouples the two channels.