Heuristic Scheduling Method of Flexible Manufacturing Based on Petri Nets and Artificial Potential Field

As for the optimal scheduling issue of closely coupled the path planning of automated guided vehicles (AGVs) and task allocation in flexible manufacturing systems (FMSs), a heuristic optimization method is proposed based on Petri nets and an artificial potential field (APF). First, a manufacturing system with AGVs is described as a task Petri net and a path one, and then its Petri net model is obtained by composing the two nets together. Second, the topology of the Petri net model is used to design the potential energy parameters for the network junctions, and, consequently, the APF is designed for the Petri net model. Third, a heuristic functions is proposed to estimate the minimal terminate times of the Petri net model by means of its APF. Further, a heuristic beam search algorithm is presented to calculate a near optimal schedule by the Petri net model and its APF. Finally, numerical experiments are carried out, and the results show that optimal or near-optimal schedules can be calculated in the reasonable times by our algorithm.