A Tuning Strategy for Unconstrained SISO Model Predictive Control

This paper presents an easy-to-use and reliable tuning strategy for unconstrained SISO dynamic matrix control (DMC) and lays a foundation for extension to multivariable systems. The tuning strategy achieves set point tracking with minimal overshoot and modest manipulated input move sizes and is applicable to a broad class of open loop stable processes. The derivation of an analytical expression for the move suppression coefficient, λ, and its demonstration in a DMC tuning strategy is one of the significant contributions of this work. The compact form for the analytical expression for λ is achieved by employing a first order plus dead time (FOPDT) model approximation of the process dynamics. With tuning parameters computed, DMC is then implemented in the classical fashion using a dynamic matrix formulated from step response coefficients of the actual process. Just as the FOPDT model approximation has proved a valuable tool in tuning rules such as Cohen−Coon, ITAE, and IAE for PID implementations, the tuning strategy presented here is significant because it offers an analogous approach for DMC.