Two-Machine Robotic Cell Scheduling with Controllable Inspection Times

This paper considers the stochastic scheduling of a two-machine robotic cell with controllable inspection times. The inspection is performed by a multi-function robot which performs the inspection of the part in transit between two machines. The robot cannot complete the part transition if it identifies a fault in the part. Instead, when the robot detects the fault, it moves back the source machine to reload the part. A characteristic of the inspection is that its required time is changed by altering the inspection cost. This generates a trade-off between the cost of quality and the partial cycle time. Initially, the cost of quality and cycle times of different partial cycles are derived based on a geometric distribution, and then the optimization problem is solved. Two versions of the problem are employed to minimize the expected cycle time or the expected cost of quality according to the concern of decision makers.