A STRUCTURAL LOAD ALLEVIATION CONTROL SYSTEM FOR A LARGE TRANSPORT AIRCRAFT

摘要

This report presents results of applying linear optimal control theory to provide significant reductions in the bending moments at the root (and other stations) of the highly flexible wing of a large transport aircraft. The effects of neglecting higher frequency bending modes and/or omitting unsteady aero¬dynamic effects are demonstrated and discussed. The efficiency of lower-order feedback control laws is also demonstrated and the dynamic requirements for the servo-actuators associated with the active control surfaces are shown to be such that they can be achieved with present-day electrohydraulic components. Structural load alleviation is shown to be possible and it is demonstrated that the synthesis problem is manageable even when based on incomplete mathematical models and imperfectly synthesised feedback control. Digital simulation was employed throughout.