Five years ago my previous iMac was randomly going to sleep instantly. I think it was a hardware problem. When I say instantly I mean instantly, literally. BOOM, asleep. Maybe once a day.
So what I did to address (not fix) this was to have Keyboard Maestro run a UNIX "at" command every minute, and what that command did was set the iMac's auto-wakeup time to two minutes from the current time. That way even if it went to sleep from the hardware fault it did wake up in about a minute.
So in a funny sense, I actually was using KM, indirectly, to trigger the computer to wake up when it's asleep.