On-line scheduling in assembly processes

The assembly system under consideration is composed with several machines, and some of these machines may be identical or able to perform the same ope rations, The manufacturing system is fully automated, and semi-finished pro ducts or components are not stored during the process. A limited flexibilit y exists since the manufacturing times can be extended within certain Emits at the expense of the unavailability of the resource. There are no conflic ts between the resources; in other words, the same machine is not used to p erform different operations for a same product. Due to the intensity of the flow of products to be manufactured, it is not allowed to reschedule produ cts that have been previously scheduled. Thus, when a new product requireme nt arrives in the system, we have to take advantage of the idle time window s. The goal is to complete the product as soon as possible. We give a real- time scheduling algorithm which guarantees an optimal makespan to any produ ct which arrives in the assembly system. A numerical example is provided to illustrate this approach.