WPNAV_LOIT_JERK - what is it? Why a WPNAV_ param?

Does anyone know what WPNAV_LOIT_JERK is?http://copter.ardupilot.com/wiki/arducopter-parameters/#wpnav__parametersThe only description there is, "Loiter maximum jerk in cm/s/s/s"As a follow up, why are the following Params prefixed with "WPNAV" ?Based on their descriptions, they don't seem to be directly related to Way Point Navigation in missions, but rather are Params that effect general behavior in Loiter, whether running a mission or not.WPNAV_LOIT_JERKWPNAV_LOIT_MAXAWPNAV_LOIT_MINA

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  • Developer

    Erik,

    It limits the maximum change in acceleration horizontally.  So acceleration is really lean angle (when we're talking about horizontal position control) so that parameter essentially limits how quickly the lean angle can change in Loiter.  So if you make it very low the vehicle will start leaning very slowly.

    Those parameter start with WPNAV_ because they're all part of the waypoint navigation library.  The waypoint navigation and loiter share a lot of features so it made sense to put them together.

    • what wold be your advice for low kv motors?  in my case, i habe been working with diferent low kv motors, in this case e800 340 kv, when enter in loiter it hovers ok, but in windy conditions it wobble or oscillate to keep the possition, i have read the documentation to figure out if this variables can fix my problem, another point is when i run it fast at stoping it oscillates too agressive,  

      so im not an expert but i think i should lower  WPNAV_LOIT_JERK to hover less agressive in windy conditios, but im not sure if the variable i should play with is that one or VEL_XY_P (shown as “Rate Loiter P, I and D”) , Maybe Rate loiter P is the variable im looking for. any suggestion?.

    • if it helps for somebody, in my case i found lowering Rate Loter I and Imax it hovers smoother,  the agressive tilt to keep the possition in loiter has gone. if lower too much, it cant hold the possition, is like drifting against the air, and then aceleates to GPS possition, it helps in both of my quads with 340KV motors, in windy conditions they hover smooth =).   Still i dont know how to change them for my small quad with 960kv motors and 9x45 props. but if i get the point i let you know. 

    • Thank you.
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