>1) does this hold for all 3 of jerk, snap and crackle, like OP suggested? They aren't the fundamental quantities you would look at, typically the output of a

>1) does this hold for all 3 of jerk, snap and crackle, like OP suggested? They aren't the fundamental quantities you would look at, typically the output of a multi body system are displacement/velocity/acceleration, but of course if you look at a plot of acceleration you can just see these quantities (at least the first and second derivative are quite easy to see) or calculate them. And of course the ride comfort is related to the smoothness of the forces you experience, which is the same as wanting to minimize the derivatives of force. But I would suggest that these quantities are quite hard to analyze quantitatively as they are, naturally, subject to far more noise. Where these quantities definitely are considered is when you look at vibrations. >2) In applications where no humans are involved (robot actuators etc.), would it make sense to minimize jerk, snap and crackle too? Yes, if you care about durability. Parts can break for different reasons, intuitively you easily understand that exceeding certain loads breaks them. Another, far more insidious, failure case is a cyclic load, which never exceeds a particular threshold. Again, vibrations play an important role there.