4 ms·

Also jounce, flounce and pounce lol https://en.wikipedia.org/wiki/Fourth,_fifth,_and_sixth_derivatives_of_position https://en.wikipedia.org/wiki/Fourth,_fifth,

by jcims 6y ago

Also jounce, flounce and pounce lol https://en.wikipedia.org/wiki/Fourth,_fifth,_and_sixth_derivatives_of_position https://en.wikipedia.org/wiki/Fourth,_fifth,_and_sixth_deriv... I thought were all useless terms but apparently snap is quite commonly used in quadrotor motion control.

rocqua 6y ago
Snap is that feeling you get when a train is braking and comes to a halt. The breaking force suddenly falls of, which is noticeable. In general, snap shows how smoothly the acceleration occurs. This allows anything that flexes (like flesh) to slowly take-up the slack. I've also heard this is important for self-driving convoys. You want the cars in the convoy to all accelerate and brake smoothly rather than jostle all the things inside them.
- b3orn 6y ago
  > In general, snap shows how smoothly the acceleration occurs. That's third derivative of position and called jerk.
  - dataflow 6y ago
    I think they're distinguishing between "how quickly acceleration changes" and "how smoothly acceleration changes".
    - rocqua 6y ago
      Nope, I confused Jerk and Snap
  - rocqua 6y ago
    Dang you are right. My bad
ragebol 6y ago
Not just quadrotor motion control, it applies to precision machinery as well. Eg. it's used in those big ASML wafer stepper machines that help power Moores Law for example, but also 3D printers etc. Low values for these derivatives help reduce vibrations in the machines IIRC.