Very well done! Interesting and comprehensible.
Your plans for the next one include any production suggestions that I'd have.
A couple of content comments:
- in the proportional demonstration, you add the weight and it doesn't recover (to 45). You say " ... it's not at the target angle, cause it has to have some error to develop the drive ...". Well, it does have error - why doesn't it correct? (around 9:00 - 9:40)
- the D & I explanations got around the calculus nicely. What I would have liked to see there was why these aspects are useful. Everyone can see that correcting a proportional error is useful. Why isn't it good enough? Sort of: "Proportional will correct, but when the disturbance is happening rapidly, a stronger correction is better & the derivative does that."
- you probably aren't going to find the time for it, but what about stability? It's so important that wouldn't a few words be justified? Maybe just an aside such as "Another important aspect of D/I is that as the error is reduced, the correcting force is also, reducing overshoot." Or something to that effect which is actually true.
Bob
Oh - I do have a production comment: if the disturbing weight were a magnet, it could be added & removed instantly, with no fiddling required.