PiggyBack #728
more than a bug fix is neededWe are all speculating based on incomplete information but it has been apparent that current concept is flawed and this could not be resolved by a software fix even if it successfully addressed whatever issues had caused the two crashes. We know that a single fault could cause the stabiliser to be driven to a position where it is hard or impossible to recover. Addressing specific fault scenarios without addressing this wider concern is not a full solution. We have partial information and those involved are competent people so we must assume that this is beng addressed however the timescales for the solution always seemed over optimistic.
A prime example is the jackscrew power, with a lot of logic and hardware upstream. Posters have mentioned, motors, but should it not be motor, singular? One brushless motor with a control and clutches. Okay, so this is probably the finest build quality there is, but there is just one motor and associated systems. This leads me to believe we are absolutely reliant on the steel cable backup - and its ability to be cranked in any scenario.
Like many relays, that INTERLOCK unit has a solid state device crowbaring the back EMF. It's one tiny solid state surface, which if shorted would leave the interlock signal continuous. The point is, the use of good old clonking relays can be rendered worthless with little more than a speck of semiconductor material. One example amidst hundreds, just on the area we're focussing on.
Just as an aside, I recall some 30 - 40 years ago a guy from the British simulator maker saying 'There is no operating system. There's no time.' A different world back then, but I know what he means. HAL mediating every step of the logic can be a terrible burden. Sometimes, knowing what's going to happen when you press a switch is worth its weight in gold.