A design method for modified smith predictors for multiple-input/multiple-output non-minimum-phase time-delay plants with feedback connected multiple time-delays

In this paper, we examine a design method for modified Smith predictors for multiple-input/multiple-output non-minimum-phase time-delay plants with feedback connected multiple time-delays. The Smith predictor is proposed by Smith to overcome time-delay and known as an effective time-delay compensator for a stable plant with large time-delay. The Smith predictor by Smith cannot be used for plants having an integral mode, because a step disturbance will result in a steady state error. Several papers considered the problem to design modified Smith predictors for unstable plants. Yamada et al. proposed a design method for modified Smith predictors for non-minimum-phase time-delay plants with feedback connected multiple time-delays. However, their method cannot be applied to multiple-input/multiple-output plants, because the method is obtained using the characteristic of single-input/single-output plants. In this paper, we propose a design method for modified Smith predictors for multiple-input/multiple-output non-minimum-phase time-delay plants with feedback connected multiple time-delays.