Smith Predictor Based Control Strategies for Nonminimum Phase Plants

The present paper proposes design strategies, based on the Smith predictor and its variants, for controlling nonminimum phase plants, by treating the right half plane (RHP) zeros of the system in the same way as the delay term in case of the conventional Smith predictor. Simple controllers, in conjunction with these Smith predictor like structures, can achieve good performance in terms of steady state error and disturbance rejection, for both type zero plants, as well as for plants with an integral mode. Additionally, here the order of the plant and the number of RHP zeros of the plant are not restricted. Simulations corroborate the theoretical results.