Design of Autoland Controller Functions with Multiobjective Optimization

Abstract

The application of multiobjective optimization to the design of longitudinal automatic-landing control laws for a civil aircraft is discussed. The control laws consist of a stability and command augmentation, a speed/flight path tracking, a glide-slope guidance, and a flare function. Mulitobjective optimization is used to synthesize the free parameters in these controller functions. Performance criteria are thereby computed from linear as well as nonlinear analysis. Robustness to uncertain and varying parameters is addressed via linear robustness criteria and via statisticle criteria computed from online Monte Carlo analysis. For each controller function, an optimization problem setup is defined. Starting with the inner loops, the synthesis is sequentially expanded with each of these setups eventually leading to simultaneous optimization of all controller functions. In this way, dynamic interactions between controller components are accounted for, and inner loops can be compromised such that these can be used in combination with different outer loop functions. This reduces controller complexity while providing good overall control system performance.