A modified Smith predictor with a new structure for unstable processes

In this paper, we propose a modified Smith predictor with a new structure f or unstable processes. The proposed new structure makes it possible to use the unstable model itself as a process model, while the previous modified S mith predictors provided no option to use a mismatched stable process model to guarantee stability. Accordingly, the proposed Smith predictor can pred ict the dynamics of the actual process much better than previous approaches . It also guarantees good robustness to modeling errors by separating servo and regulatory problems. Moreover, it demonstrates good disturbance reject ion performances because the adjustable parameters of the PID controller fo r the regulatory problem are tuned systematically with an internal feedback loop.