Control: past, present and future

Automatic control developed historically as a necessary consequence of replacing human or animal power by wind and water power and later by steam power. Its beginnings were empirical, but an important contribution to the theory was made by Clerk Maxwell, and later the development of feedback amplifiers led to intensive theoretical work in the U.S.A. By 1945 a well-developed and highly successful theory was available, and wide applications have been made. In more recent times, theoretical effort has been concentrated on problems of guidance, using the calculus of variations. The incentive here was to solve aerospace problems, but there have been some applications to industrial problems. This theory seems to have a narrower range of applications than the earlier work. The development of the digital computer has placed in the hands of engineers a tool of unrivalled flexibility and power for the control of processes. By contrast, our theory is at present unable to exploit this power with full effect. The most promising field for control theory and application in the next five to ten years seems to be the application of computer control to all types of industry, and the development of the corresponding theory.