Hi,
can somebody explain me more detailed the Imax Values?
Well the AC2 Tuning guide says it is the maximum amount of Rate_I can build up.
But why should i limit it for Rate?
Flying in Acro mode i need in (my opinion) relative high i and imax Rate Value.
For my 330 Quad Ptich and Roll Values:
RateP = 0.120
RateI = 0.300 (tried some higher but don´t see much difference - maybe some wobbles - - with lower values the Angle isn´t hold)
Rate IMAX = 90 (Tried higher values with no effect - with lower values the Angle isn´t hold)
I didn´t know this imax Rate value from a Mutliwii Controler?
Is there any reason keeping it low (like the default values) ?
I also read that i should keep I relativ low arround 0.1 - why?
Florian
Replies
Hi,
i alreadytried a higher P term (i started with i = 0). But it quickly starts oscilating.
With windy weather i think i even have to lower Rate P
With low Rate i and imax i can´t hold the angele in acro mode (and i really like flying in Acrommode ;-) )
With low values it flies like a pendular or a swngboat when i don´t manual correct the angle...
Thanky for your explanation. In theory i understand now why it could be usefull to limit the I-term with imax.
But practical... i am not sure if i have any disadvanteges with my settings now . At the moment i am just trying acro and stablemode. Later i will use Nav and Loiter etc.
Classically, the I term is only used to close the steady-state error which is left behind from the P term. The I-term can cause problems in some cases, where it builds up excessively, so an Imax is used to prevent that from happening. Such an example is when the setpoint moves a great distance very fast, and the process response is limited. I-term will build up, and will cause an overshoot. Imax can prevent this. In this case, Imax should only be big enough to allow the I-term to correct for steady-state error from the P-term.
If you have to use a lot of I-term, then it might be the case that your P-term is too low.