Calculate rotational acceleration

[yoos]

Rotational acceleration is hard-coded to zero in the attitude estimator. Consequently, previously valid PID gains for rotational position and velocity now result in instability.

This was a major oversight.

[kylc]

What are the acceleration estimates needed for? If we're already seeing noise on the position and velocity measurements (#51), won't the velocity derivative be far too noisy?

[yoos]

We have position estimates, not measurements. Likewise, we should have acceleration estimates.

Hmm. I concede that when I added the angular acceleration controller and estimate, it was more for sake of completeness than for need. The controller gains are set to 1.0 in all units anyway, effectively making the controller a passthrough.

While working on what is currently implemented as the "rocket angular acceleration controller", I felt that the cascading PID control model puts an unnecessary constraint on the types of controllers we can implement. That is fodder for another ticket, though.

Regardless, would like to leave the angular acceleration estimate in place. In the current setup, PID gains of 1,0,0 essentially turn a given controller into a passthrough.. kinda.