Patience (Patreon)

Hey all! Just a quick update here since it's been a little while. 

It may seem like nothing has happened in a few weeks, but it's far from the truth! I've been overhauling the rocket landing simulations, flight software, pre-flight checks - basically everything associated with getting a model rocket to land upright.

The bulk of the work has been in the flight software. A persistent problem in the BPS.space landing test program has been horizontal drift on the vehicle right when it touches down. Especially because we're landing in the grass, the rocket needs to be sliding from side to side as little as possible.

This is reeeeaaaaaalllllllyyyyyy hard to get right. First you need to measure the drift as the vehicle is rolling: which direction is X and Y? What about when it's a mix of the two? You need some tricky math to fix this. Then when it's time to correct for that drift, the vehicle might still be rolling so you need to rotate those orientation setpoints BACK into body frame instead of global. Finally you need a well-tuned PID controller, because each axis now has 2. One for horizontal control, which feeds into the stability control PID. It's a nightmare.

If this doesn't make sense, don't worry! We're under a week away from the next drop test, so we should get some solid results soon! I'll explain it all in much more depth when that happens.

Anyway, this is all to say that I've been working hard for the last few weeks without any super cool photos or videos to show for it. I promise it'll be worth the wait.

Of course if you'd like updates far more often, I recommend staying tuned to @joebarnard on Twitter! Lots of details on progress are posted there.

Blue skies,

Joe