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Permalink Reply by James on May 7, 2012 at 5:26am

im still fairly new to this myself, but have been getting to grips with PID tuning recently and have been getting some very good results with a much heavier Hexa.  although the values will be different due to different weight/props/motor distance the underlying concepts should hold true, so i hope it can help a bit.

 

the main values you need to concentrate on are the RATE settings, if you have a variable channel 6 the best is to assign the variable youre working with and set max/min values so that you can return to your "known" value in the centre of the dial.  make sure the value is being changed before taking off as i have found some of the options to be broken recently (RATE D tuning doesnt work in 2.5.3 and nearly cost me a heavy crash)

 

• you seem to have a bit of a nervous wobble with fast oscillations as the quad hits turbulence and reacts to stick input so my first advice would be to lower RATE P.  if youre currently flying with the default 0.140 perhaps set max 0.18 and min 0.1 and fly tuning it down 'til that nervousness goes away.
• then to counter that overshoot when letting go of the stick and returning to level.  tuning down RATE P will probably reduce this effect in any case, but the next value to adjust is RATE I.  higher values should slow the turn rate as it gets close to the desired angle but be careful as some combinations of RATE P and RATE I can introduce slow oscillations.  again, set your max/min values so that you can return to a known configuration by setting the dial to its centre position and try different values.  in theory it should be something like 30% of the RATE P value - in my case i am flying with RATE P 0.095 and RATE I 0.02.
• finally theres RATE D which basically acts as a damper against sudden changes, and can greatly improve the smoothness of flight when hitting turbulence or dropping into your prop wash.  as i said, at least in v2.5.3 the channel 6 tuning of this value is broken so i have set it by trial and error (and a great deal of comparing the values that work for others).  currently i am flying with RATE D at 0.01, but many others have this value up to 0.012

as for the yaw rebound i too am looking for an answer to this question (http://www.diydrones.com/forum/topics/yaw-rebound) and havent made any real progress yet trying to tune it out.

 

regards,

 

james

 

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Permalink Reply by Simon on August 21, 2012 at 7:37am

That crash at the end...could it have been caused by low voltage? I know my quad goes a little crazy when the voltage gets too low.

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