Optimal digital redesign of a cascaded continuous-time system with input time delays

A new optimal digital-redesign approach for the input time-delay continuous-time cascaded system is proposed in this paper. It shows that the states of the sampled-data system with the digitally redesigned control law closely match those of the original cascaded continuous-time closed-loop system with analogue control law at any instant between sampling periods. Moreover, the developed digital control law can be implemented using low-cost microcomputers with a relatively longer sampling period. Also, it utilizes the innovative one-duration description of input time-delay sampled-data system, that is suitable for any value of input time delay, even larger than one sampling period. An illustrative example is presented to demonstrate the effectiveness of the proposed design methodology.