Pilot-vehicle analysis of multiaxis tasks

In missions where high c ognitive and managerial requirements are placed on the p ilot, or where failures may significantly degrade one or more air- craft control axes, the pilot must divide his attention among several tasks. The pilot and sys- tem behavior in such divided attention conditions, and the combination of pilot ratings from single to multi-axis c onditions are treated using classical and optimal control models for the human in a com- plementary fashion. It is shown that the crossover frequency and closed-loop system performance for a given axis under divided attention will be less than full attention values while the remnant and the phase m argin will be greater, and that t he model-based trends are consistent with experiment. Also, the optimal control performance index used in the pilot and system behavioral modeling, when calibrated w ith s ingle-axis correlations, shows potential f or t he development of subjective rating estimates for multi-axis t asks.