Two-DOF controller designed by CDM incorporating FFC for a Smith Predictor scheme

The Smith Predictor is popular and very effective dead-time compensator for stable process. However, it is very sensitive to uncertain system and variable time-delay. Therefore, the design method of a controller robust to the parametric uncertainties for the plant parameters is an important problem. Coefficient Diagram Method (CDM) is shown to be an efficient control technique to solve this problem. In this paper concerned with a design method of two degree-of-freedom (2DOF) controller by CDM incorporating feedforward controller (FFC) for a Smith predictor scheme. The control system is devised to improve properties of set-point tracking. The simulation results of the control systems utilizing show that the proposed method is good control performance of set-point tracking and robust whilst giving the desired time domain system performance.