The neural network project was sponsored by ARPA to determine the feasibility of
using artificial intelligence to compensate for thermally induced machining errors.
The test setup consisted of a 30 inch copper tube affixed with a couple dozen thermocouples.
Fiber optic non-contact probes measured the displacement of the tube relative to
a fixed Invar rod while being randomly heated by computer controlled industrial heat
guns. The displacement and temperatures were used to train a 3 layer back propagation
neural network and the same network was then used to predict future displacements
under similar conditions. The same concept was then used to outfit a CNC lathe and
the machining errors were predicted as a function of the temperature profile of the
lathe. The network was able to correctly predict errors in both setups to about
a 95% accuracy.