Combined Scheduling and Control with Diurnal Constraints and Costs Using a Discrete Time Formulation

Integrated scheduling and control is a new approach that seeks to unify the objectives of the various layers of optimization in manufacturing. Recent efforts in this field have used a continuous-time, slotbased formulation. This work investigates combining scheduling and control using a novel discrete-time formulation, utilizing the full process model through the entire horizon. This discrete-time form lends itself to optimization with time-dependent constraints and costs. This work demonstrates the value of time-based parameters in this paradigm by applying cooling constraints and energy costs of a sample diurnal cycle. A psuedo-binary variable method is presented to ease the computational burden of this approach. The formulation is applied with a generic CSTR system in open-loop simulations over a 48-hour horizon.