Modelling a Robotic Cell and Analysis Its Throughput by Petri Nets

The place/transition Petri nets (P/T PN) and timed Petri nets (TPN) are used here for modelling the robotic working cell where the robot attends three machine tools processing in sequence the part in order to obtain the final shape of the product. The cell contains the input and output conveyers. The input raw material has to pass the way from the input conveyer consecutively through all machines to the output conveyer. The P/T PN model of the cell is constructed. Then, by means of supervision, the possible sequences of operations are ensured in order to avoid any ambiguity. Finally, the throughput of the robotic working cell is found by means of timed Petri nets (TPN) for all simple schedules. By means of comparison particular schedules as to the throughput the best throughput is found.