On the Limits of Manual Control

Theoretical predictions and experimental data for the limits of manual control of unstable oscillatory second-order controlled elements are presented. At the limits of manual control, amplitude distributions of the system error and operator output were nearly Gaussian. The quasi-linear describing function model of the human operator implied from analysis of the experimental measurements indicates that the operator was capable of generating equalization equivalent to a double lead and that, for certain controlled elements, he adopted a response behavior analogous to quasiprecognitive tracking with a compensatory display.