PH--Postharvest Technology Automatic Control of Crossflow Grain Dryers, Part 3: Field Testing of a Model-Predictive Controller

In Part 3 of the paper on automatic control of crossflow grain dryers, the field testing of newly developed model-predictive controller is described. The system showed excellence in accuracy, stability and robustness. The moisture content of maize was controlled to be within ±0·7% w.b. of the moisture content to the set-point, at inlet-moisture contents ranging from 21 to 32% w.b. and drying-air temperatures from 85 to 120°C. The controller also displayed excellent compensation characteristics to changes in the drying-air temperature.