Robust Lyapunov constrained sampled data eigenstructure assignment using the delta operator with application to flight control design

Abstract

A robust sampled-data eigenstructure assignment flight control law is designed for the yaw-pointing/lateral-translation maneuver of the flight propulsion control coupling aircraft. The flight control design uses the unified delta model, which is valid for both continuous-time and sampled-data operation of the aircraft. A robust stability result which uses a Lyapunov approach is extended to delta operator systems is extended. An objective function is chosen that weights both the heading angle due to a lateral flight path command and the lateral flight path angle due to a heading command. The design method minimizes the objective function with constraints on the time constants of the dutch roll, roll, and lateral flight path modes; the damping ratios of the dutch roll and roll modes; the new Lyapunov sufficient condition for robust stability; and the minimum singular value of the return difference matrix at the aircraft inputs. This design satisfies the new robustness condition, yields a minimum of the smallest singular value at the aircraft inputs of 0.55, and yields a better transient response than an earlier design. >