Schedule execution by a Holonic Manufacturing Execution System

The paper presents and evaluates an integrated approach for production control and production scheduling: schedule execution. Schedule execution involves taking on-line resource allocation decisions, based on the existing schedule but also considering the actual state of the resources and orders on the shop floor. The system takes into account the output from a scheduling algorithm. The system uses a Holonic Manufacturing Execution System (HMES) to execute the schedule. The paper evaluates this integrated approach in a number of experiments. The experiments show an improved responsiveness of the HMES towards breakdowns, when using a schedule execution approach. Both the variation and the average performance suffer less from a breakdown compared to an approach where the HMES never deviates from the planning or uses no planning at all. This responsiveness is achieved while maintaining a good separation of concerns. On the one hand, every scheduling algorithm can be used unmodified. The HMES adds responsiveness to the functionality the scheduling algorithm already offers. On the other hand, the HMES compensates for possible simplifications in the schedule.status: publishe