ILP models for scheduling while minimizing peak power consumption

Abstract

The Peak Power Minimization Scheduling Problem (PPMSP) is a job shop scheduling problem where peak power consumption is minimized, as opposed to makespan, total cost or some other common objective. A formal integer linear programming (ILP) model is developed for this scheduling problem, called the initial PPMSP model. This initial model is then used to create the Scheduler, an application for creating production schedules given unscheduled sets of production data constrained under precedence relations. The Scheduler uses a free solver called GLPSOL. The Estimator is another application that, given a production schedule, generates a plot of the expected power consumption over the course of the schedule. Later, an alternate PPMSP model is discussed, which aims to improve solution times by using fewer binary variables. Testing indicates that the alternate model provides no significant improvement in practice. Much better solution times can be achieved with more powerful solvers, such as CPLEX.