Hierarchical approach to adaptive control for improved flight safety

M Idan, M Johnson, AJ Calise - Journal of guidance, control, and …, 2002 - arc.aiaa.org
M Idan, M Johnson, AJ Calise
Journal of guidance, control, and dynamics, 2002arc.aiaa.org
Following failures of primary aerodynamic actuators, safe ight can be maintained by
introducing alternative actuation systems, such as analytically redundant secondary
aerodynamic surfaces and propulsion, for higherpriority stability and control augmentation
tasks. An intelligent hierarchical ight control system architecture is presented that is
designed using nonlinear adaptive synthesis techniques and online learning neural
networks to enhance ight safety. Pseudocontrol hedging is used for proper adaptation in the …
Following failures of primary aerodynamic actuators, safe ight can be maintained by introducing alternative actuation systems, such as analytically redundant secondary aerodynamic surfaces and propulsion, for higherpriority stability and control augmentation tasks. An intelligent hierarchical ight control system architecture is presented that is designed using nonlinear adaptive synthesis techniques and online learning neural networks to enhance ight safety. Pseudocontrol hedging is used for proper adaptation in the presence of actuator saturation, rate limits, and failure. The hierarchical structure incorporates nonactive secondary actuation channels that are engaged after a failure of a primary control surface is encountered. The methodologyrequires only the knowledge that a failure in a speci c actuator has occurred. A model of the failed aircraft, the failure type, and the failure size need not to be known: The neural network element of the secondary channel will adapt to the failed actuator effect. The secondary control channels are designed to account for the typically lower authority and degraded performance that can be expected with secondary actuation systems. The proposed hierarchical ight control architecture is attractive, in particular, as a retro t to existing certi ed ight control systems for enhanced ight safety. The proposed ight control architecture is evaluated in a nonlinear ight simulation environment, demonstrating its retro t features.
AIAA Aerospace Research Center