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Modern control applications to manual control-historical perspective and future direction

Control theory has been applied to modeling human operator response for the past thirty years. Progress in manual control theory and applications has, therefore, been intimately dependent upon the state-of-the-art in control theory. This close relationship is particularly evident in the modeling methodology dominant during certain periods of its history. Thus, in the fifties and early sixties, classical control theory was the underlying foundation of manual control. However, with the advent of modern control theory in the late sixties and seventies, there has been an increasing application of these new tools; specifically, linear optimal control methods are utilized in characterizing human response as a controller in closed-loop regulation or tracking tasks. This paper attempts to put these developments in manual control in historical perspective. Existing methodology is assessed in terms of the practical requirements in manual control system evaluation, test and design. The merits and limitations of present methods are identified followed by an enumeration of desirable objectives and directions in future research.