Non-convex large-scale scheduling for energy-efficient flexible stamping systems

Based on the weighted placed-timed Petri Net models of flexible manufacturing system, this paper considers a scheduling problem which minimizes both productive and idle energy consumption subjected to the general production constraints. The considered problem is proven to be a non-convex mixed integer nonlinear program. A new reachability graph-based discrete dynamic programming approach is proposed for generating near energy-optimal schedules within adequate computational time. Our results on an industrial stamping system show the effectiveness of the proposed scheduling method in terms of computational time and deviation from optimality.