An Anticipatory Control for a Flexible Manufacturing System Based on the Perception of Mobile Units Using WSNs

摘要

In this paper, we design and evaluate a control system which, by using as input RSSI measures, allows anticipatory movements of robotic arms decreasing idle times at the CIMUBB Laboratory. Classical Log-Normal model, which relates the strength of a signal received by a node with the distance at which the sender of the signal is, was adopted. The hidden state of the system is determined by the Extended Kalman filter which allows us to estimate the distance and the speed of pallets moving over a closed-loop conveyor belt. From these estimates, remaining time in which the pallet will get to a stopping point near the robot is determined. This information is finally processed by a controller to determine the instant at which the robot must operate and handle the pallet. Both, a Proportional-Integral and a Fuzzy controller, were implemented and evaluated. Results show the feasibility of using wireless signals to accomplish the described goal, with some practical restrictions.