Coupled task scheduling problems were first studied more than 25 years ago. Several complexity results have been established in the meantime, but the status of the identical task case still remains unsettled. We describe a new class of equivalent one-machine no-wait robotic cell problems. It turns out that scheduling of identical coupled tasks corresponds to the production of a single part type in a robotic cell. We describe new algorithmic procedures to solve this robotic cell problem, allowing lower and upper bounds on the production time, and discussing in particular cyclic production plans.

International audienc

Abstract. In scheduling literature, the notion of machine non-availability periods is well known, for instance for maintenance. In our case of planning chemical experiments, we have special periods (the week-ends, holidays, vacations) where the chemists are not available. However, human intervention by the chemists is required to handle the starting and termination of the experiments. This gives rise to a new type of scheduling problems, namely problems of finding schedules that respect the operator non-availability periods. These problems are analyzed on a single machine with the makespan as criterion. Properties are described and performance ratios are given for list scheduling algorithms.