Stability and Performance of Manned Control Systems

This study demonstrates that the human-operator transfer function approach may be generalized; from a variety of published experimental data, "capability bounds" upon the transfer function parameters are formed. With such ranges defined, these parameters, forming a type of variable structure, can be used as a mapping function to display in the complex plane the boundaries of human adaptive capacity. These boundaries contain a collection of "critical points" which, used in conjunction with the plant Nyquist contour, permit interpretation of system stability characteristics. Experimental verification of the theory is obtained from previously published empirical studies. A man-monitored system configuration also appears to be susceptible to such stability analysis.