Optimal Control Structure Selection Based on Economics for Continuous Cross-Flow Grain Dryer

In this work, we present the control structure selection problem based on steady-state economics applied to a continuous cross-flow grain dryer model. The optimal selection of the controlled and manipulated variables and their set-points can be obtained for various external disturbance scenarios if an appropriate mathematical programming problem is formulated. Simulation results show that the economics performance of classical open loop and closed loop structure used for dryer control can be improved by the use of linear combination of controlled variables and also by the use of a hierarchical control structure. In addition, we study several alternatives (sub-optimal) control structures that show an acceptable economic performance.