Advanced Planning and Scheduling Systems based on Time Windows and Constraint Programming

APS (Advanced Planning and Scheduling) systems are designed for drawing up production plans by employing task allocation strategies based on simple heuristic tools. The task allocation procedures presented here, allow for a detailed analysis of the production results, as well as for the possibility of setting different production planning scenarios. Task allocation heuristics for APS systems here consider the use of tasks “time windows” and constraint programming to meet deadlines and important dates for scheduling delivery. These heuristics, with tasks allocation either at the beginning or at the end of the task time window, eliminates the need for a priority scheme and represent a contribution to intelligence, flexibility and agile manufacturing. To illustrate the advantage of the proposal, a scheduling for batch production plants is presented. The short-term constraints considered were: restrictions on storage for intermediate products on shared resources (equipment), and a method for on-demand rescheduling.