CliveL
I've noticed that several postings refer to the production AICU as a 'digital' control system. Strictly speaking it wasn't; it was a hybrid digital/analogue system where the inner dynamic control loops (the closed loop part) were analogue systems operating to maintain limits defined by the digital arithmetic processors. This allowed us to have quite sophisticated control 'laws' which would have been next to impossible with a pure analogue system.
Tee hee, can't get away with anything here anymore Clive
Yes, of course (as ever
) you are correct; it was technically a hybrid system: The servo loops, in terms of ramp and spill door demand signals and resolver position feedback signals etc. DID use conventional analogue drive and servo amplifiers within the AICU, it was the massive arithmetic computation UP-STREAM of these that was digital. I always used to like to refer to the AICS as 'an analog front end with a digital brain'. But that's just me
.
But as you say Clive, none of the control law sophistication (including the synthesising the intake face total pressure and local Mach numbers from mainline aircraft raw air data) would have been possible using analog computation.
Best regards
Dude
