The active loads control functions to be designed should be a control law extension to the standard electronic flight control system which is mainly designed regarding handling qualities. As control surfaces the conventional aerodynamic surfaces are used.
From the overall requirement "robust load reduction at certain structural segments without interfering loads at other positions and without interfering handling qualities too much" the following computational criteria have been developed and successfully applied in mode and loads control function design:
Design of load control functions
A typical problem in synthesis of load control functions is to reduce loads at some structural points but not to increase loads at other positions up to a defined level. The min-max optimisation strategy of MOPS provides a convenient way to handle such problems. This strategy allows either to achieve the demanded load values everywhere on the structure or to detect design conflicts easily.
To this end, a process for integrating flight mechanics and aeroelastic models and model data has been developed and applied. This process results in nonlinear integrated flight and aeroelastic dynamics models for analysis in the time and frequency domain. The process removes overlaps between both types of model data, and transforms unsteady aerodynamic loads from the frequency into the time domain. Structural data are obtained from lumped-mass condensations and modal analysis of a finite element model of the airframe.
Flexible aircraft dynamics have become and integral part of our Modelica Flight Dynamics library .