Frequency domain measures of human performance under G-stress

An experimental/analytical study of human performance under linear acceleration stress was jointly undertaken by the Aerospace Medical Research Laboratories (AMRL), Wright-Patterson Air Force Base (WPAFB), Ohio, and the University of Connecticut. The experimental phase involved a steady-state compensatory tracking task in the lateral plane, under three experimental conditions: (1) Static (fixed base) tracking, (2) Tracking under G-stress of 5g in the z-axis, and (3) Post-runs (static runs immediately following condition (2)). The experiments were performed in the AMRL centrifuge (DES). The analysis of the data yielded, for the three conditions, the operator empirical describing functions, the control remnants, and the performance scores (RMS tracking error). The data exhibit two major effects of the G-stress: (1) Significant increases in the operator´s remnant and RMS error levels under G-stress, as compared to the static-condition, and (2) Lower describing function magnitude in the post-run condition (presumably an accumulative G-effect). In conjunction with these experiments, the Optimal Control Model (OCM) is applied to predict the pertaining frequency measures. The empirical data are reporduced by the OCM, and the performance decrements under G-stress modeled by adjusting the appropriate parameters.