Dear Stacy Haponik: ... The derivative of jerk has no standard name. Specifications have been written to limit jerk for passenger vehicles. No limits exist for higher derivatives. David A. Smith
Read the full replyIn Kinematics class we were learning about cam design, and about how you want to minimize the 'jerk' and 'ping' of the follower on the cam. I understand jerk. That is what I feel when I'm in a car which suddenly accelerates. I feel jerked back.
I don't know what ping is, other than the derivative of the jerk. How would I feel ping?
Also, does the derivative of ping have a name?
Dear Stacy Haponik:
The derivative of jerk has no standard name. Specifications have been written to limit jerk for passenger vehicles. No limits exist for higher derivatives.
David A. Smith
"N:dlzc D:aol T:com \(dlzc\)" wrote in news:NAaIf.32656$jR.23113@fed1read01:
I'll go a little further than David.
When you model a mechanical system you pretty much lose interest at acceleration, for passive systems.However, if you try and model feed- forward, or feedback systems, you usually include both integrals and differentials of the signal of interest.
The human proprioception demands such a feed forward device - you want to hold your head in the same place, so you want to exert a force so your feed forward system cares about jerk.
If a second order feedforward controller was justified, you'd worry about d jerk/dt, but in practice that does not seem necessary.
Cheers
Greg Locock
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