H Infinity Robust Control for Gust Load Alleviation of Geometrically Nonlinear Flexible Aircraft
This addresses structural load reduction for very flexible aircraft, which is an incremental improvement in aeroelastic control.
The paper tackled gust load alleviation for very flexible aircraft by designing H Infinity robust controllers on reduced-order models, demonstrating that these controllers can robustly alleviate gust loads when applied to high-dimensional nonlinear aeroelastic systems, with validation on full nonlinear models for UAV and flying-wing configurations.
H Infinity robust control synthesis for gust load alleviation of very flexible aircraft is presented. The controller is synthesised on a compact reduced-order model comprising 8 degrees of freedom for the UAV configuration and 9 for the flying-wing, obtained through nonlinear model order reduction of the coupled fluid-structure-flight dynamics system, and validated on the full nonlinear model. The control architecture employs trailing-edge flap deflection as the actuator and wing-tip displacement as the performance output, with an input-shaping weighting function Kc that governs the trade-off between structural load alleviation and rigid-body trajectory deviation. Results are presented for a Global Hawk-like UAV and a very flexible flying-wing configuration. The methodology demonstrates that H infinity controllers designed on low-order ROMs can robustly alleviate gust loads when applied to high-dimensional nonlinear aeroelastic systems.