Optimal scheduling of no-wait robotic cell with multi-type parts

Abstract

It is shown that finding an optimal schedule for a no-wait robotic cell with multi-type parts is equivalent to finding two correlative sequences:parts input sequence and robot move sequence.The problem is solved by avoiding two types of conflicts which may occur when two or more parts use a workstation or the robot at the same time.The entering times of parts are choosen as the decision variables and a mathematic model is developed with the notion of prohibited intervals.A dynamic branch and bound algorithm based on the graph theory is proposed to search the optimal solution.The computational results on a automated printed circuit board(PCB) electroplating line and some random tests indicate that the algorithm is effective.