From my perspective, the interesting patent to look at is...

From my perspective, the interesting patent to look at is WO2009026642A1.
This patent details the system for stabilizing the boom as well as the system for locating the working tip in 3D space. This is the clever bit.
This patent was submitted by the original two inventors of the bricklaying machine, Mark Joseph Pivac and Michael Barrington Wood.
It was done after the bricklaying patent and I am guessing was done to shore up there position with respect to the technology being able to be used in other areas other than bricklaying.
this patent like the original one was assigned to Goldwing Nominies Pty Ltd, which FBR took over when it took the IP public.
I have searched both these guys names for other patents , they both are very prolific when it comes to inventing things, however, this patent and the original bricklaying machine patent seem to be the only two pertinent to FBR, at least at this time.
I have attached WO2009026642A1. It makes for good reading and explains in great detail what really is happening in the background.
I suspect this is what is interesting to CAT...