Automated Tuning of a Baseline Flight Control System with Maneuver Load Alleviation for an Energy-Efficient Passenger Airplane

Abstract

This work presents a longitudinal baseline n_z flight augmentation system (FAS) which is representative of those employed in modern fly-by-wire civil aircraft (regarding the pull-up maneuver loads) along with a maneuver load alleviation (MLA) system which reduces sizing loads. These active control functions are applied to a flexible and energy-efficient aircraft. During the iterative aeroelastic optimization of the preliminary aircraft design, the evolution of the aircraft design and structure call for an adjustment of the control system tuning. An optimization-based procedure is proposed to fully automate the multi-objective control tuning process. This brings the aircraft design closer to an automated multidisciplinary optimization loop regarding the active control functions. The proposed design control approach is demonstrated on a mid-range aircraft configuration and the analysis of the closed-loop behavior and maneuver load figures shows a good tracking of the pilot input and a maneuver load alleviation performance of 7.7% to 10.9% (analyzed for each considered flight point / model separately).