Stable, distributed, real-time scheduling of flexible manufacturing/assembly/diassembly systems

The authors consider general flexible manufacturing/assembly/disassembly systems with the following features: (i) there are several types, each with given processing time requirements at a specified sequence of machines; (ii) each part type needs to be produced at a prespecified rate; (iii) parts may incur variable transportation delays when moving from one machine to another; (iv) set-up times are required whenever a machine changes from a production run of parts of one type to a run of another type; (v) some part types may also need assembly or disassembly; and (vi) a proportion of parts of a part type may require separate routing on exiting from a machine, for reasons including, but not limited to, poor quality. The authors exhibit a class of scheduling policies implementable in real time in a distributed way at the various machines, which ensure that the cumulative production of each part type trails the desired production by no more than a specific constant. The buffers of all the machines are guaranteed to be bounded, and the system can thus operate with finite buffer capacities