Control of Nearly Singular Decoupling Systems and Nonlinear Aircraft Maneuver.

摘要

We treat the question of control of a class of nonlinear systems using state variable feedback whose input-output map is nearly singular. Although the existing decoupling theory is applicable to such systems, this requires large control which may not be permissible. Considered here is an approach of decoupling using state variable feedback in an approximate sense, but it requires small control magnitude. A decoupling scheme is presented which gives rise to a singularly perturbed system describing the fast dynamics of the control vector. The quasi-steady-state solution of the system gives a control law which decouples the system in an approximate way. The controller includes a law for approximate decoupling of roll angle, angle of attack and sideslip in rapid, nonlinear airplane maneuvers is derived. Simulated responses of the closed-loop system show that large simultaneous lateral and longitudinal maneuvers can be accurately performed in spite of uncertainty in stability derivatives. Keywords: Decoupling control; Nonlinear system; Flight control; Singular perturbations; Reprints. (EDC)