An approach to the control of processes with pure time delay

The advent of on-line digital computers and relatively large-storage supervisory computers allows the possibility of improved control of processes containing pure time delay (distance/velocity lag). Such processes frequently occur in industrial plants and their control is also complicated by the fact that both the magnitude of pure time delay and the values of the parameters of the minimum-phase elements in the process may vary with time. Furthermore extraneous disturbances of time varying and unknown power spectra will cause further control difficulties. This paper contains an outline of a new general approach to this problem in which a digital computer is used as the main control element to implement a scheme designed to optimize the performance of such systems.