Fuzzy logic control of automated screw fastening

In this paper, we present an intelligent control strategy for automated screw fastening. In automated assembly processes, there is a large number of dedicated stations for various types/sizes of screw fastening. Problems found in current processes include cross-threading, screw jamming, slippage and the need to apply precise torque. The intelligent controller developed supervises the integrated process of an electric driver mounted on a robotic positioning system to fasten screws. The new scheme controls continuously the motion and driving stages to avoid process caused failures, to achieve a desired precise torque and to detect bad parts at early stages of the assembly. Initial results are encouraging.