An Analysis of Pilot Adaptation in a Simulated Multiloop VTOL Hovering Task

Human pilot adaptation in a simulated multiloop VTOL hovering task was investigated with a series-loop-closure model. Using the model equations, the pilot-model adaptable parameters were computed from rms hovering performance data measured in flight simulator experiments for a variety of VTOL aircraft configurations. Variations in the aircraft configurations affected both the aircraft's dynamic characteristics and its response to simulated turbulence. The pilot's pitch-loop adaptation generally correlated with the frequency-domain characteristics of the pitch response to turbulence and the pitch response to control inputs. The results of the study show no specific low-frequency attitude gain requirements that must be satisfied by the pilot for the attitude disturbance and dynamic characteristics considered. The influence of the aircraft position-loop characteristics on pilot pitch-loop adaptation was important only for configurations that had small attitude disturbances. For these cases the requirements for position-loop control apparently determined the minimum acceptable pitch-loop crossover frequency. Results also show that the pilot preferred to adjust pitch-loop gain by changing control-stick sensitivity (aircraft gain) rather than by changing his internal gain.