Smith predictor and modifications: A comparative study

This paper analyzes the performance and robustness of some of the structures of dead-time compensators that have been proposed in literature. The analysis is made using the two most typical models of processes with delay that are found in the process industry. All the structures are compared to a simple two degree of freedom Smith predictor. The comparative analysis shows that for the cases studied this simple structure gives the same performance as the others. Also it is shown that the tuning of this structure is simple because the tuning parameters have the usual physical meaning. Some simulation examples illustrate the results.