Experimenting with RSSI for the perception of moving units in intelligent flexible manufacturing systems

The incorporation of autonomous wireless devices in monitoring and control supporting in industrial systems is an emerging issue which opens a wide spectrum of possibilities. Intelligent flexible manufacturing systems might require a knowledge of the time a pallet or any other approaching transport unit needs to get a flexible manufacturing cell (FMC), for early reaction to the arrival of one of these. In this paper, we evaluate RSSI as an information source to estimate the arrival time of pallets equipped with XBee wireless modules transported to and from FMCs through a conveyor belt. Obtained results show us that in indoor environments RSSI can be used in short distances with strong transmission power, being also able to determine the order of the pallets moving on the conveyor belt.