A closed-loop forebody vortex flow controller for a generic X-29A aircraft

1995 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. A controller design methodology for systems with continuous and bang-bang control effectors is applied to the design of a high angle-of-attack lateral/directional regulator for the X-29A aircraft equipped with forebody vortex flow control nozzles. The closed-loop control law is full state feedback, and is synthesized using a linear time-invariant generic model of the X-29A aircraft. Designer specified weights in a cost function permit the designer to systematically proceed from one candidate design to another by trading-off closed-loop system response, aerodynamic effector activity, and forebody vortex nozzle activity to achieve various levels of performance. Robustness of the closed-loop system is investigated with respect to variations in the sign and magnitude of the yawing moment due to sideslip angle derivative, and to a failure in sideslip angle feedback. Results demonstrate that by proper selection of the weighting elements, the forebody vortex nozzles together with the aerodynamic control effectors can be modulated to significantly damp perturbations in sideslip angle and body axis yaw rate, compared to a controller design which uses only the aerodynamic control effectors. The controller designs are shown to be reasonably robust with respect to the particular parameters investigated.

A closed-loop forebody vortex flow controller for a generic X-29A aircraft Conference Paper