@pauljatherton wrote:
My Tarot Pro Hexacopter has been performing flawlessly on RC5. Tonight I thought I would have a go at Autotune just to test the feature, and it flagged up a couple of very strange behavioural issues during the AT process which I thought I should share with the devs. Firstly, the log of this AT flight can be downloaded from here: https://dl.dropbox.com/s/5naunz10drq6lqg/ATUN.BIN?dl=0
ATune process followed: As this is a hexacopter with 13" CF props, I followed the recommendation in the wiki and set filtering to 10Hz ( both ATC_RAT_RLL_FILT and ATC_RAT_PIT_FILT. Was set to 20Hz up until now).
AUTOTUNE_AGGR set to 0.1First set to roll only and in Position Hold. Launched copter and turned such that it was pointed into wind (so roll axis across wind as instructed in wiki). Ran autotune, and these are the observations for the roll axis:
1. It initially maintained its position despite there being 5mph winds, but within a couple of minutes started drifting down wind, with no intention of coming back - I think I read that it would occasionally re-position with AC3.5, but did not observe this. I repositioned the copter manually close to the starting position...
2. Upon releasing the pitch/roll stick, the copter immediately yawed about 30deg and climbed a few metres. This is strange behaviour number 2! I repositioned the yaw nose into wind, and the autotune carried on and eventually completed. I switched out of autotune, then back into autotune, then landed and disarmed, then out of autotune. I then checked the PID changes made to the roll axis.
3. Strange behaviour number 3 is that when tuning the roll, instead of twitching perfectly in the roll axis, I observed that most of the twitches were diagonal in axis.Reconfigured to autotune the pitch axis, armed, and launched a second time (still powered on same set of batteries). This time I had the right side pointing up wind. So for the Pitch axis:
1. Again the copter drifted from the start position and on moving it back to safety, it yawed through 90deg this time, so I corrected yaw with rudder input and it yawed a second time! Corrected again.
2. Also observed that the twitches were being applied diagonally again rather than purely in the pitch axis. I managed to complete the autotune for pitch, land, disarm, switch out of AT etc, and again checked the changes to PIDs.After tuning, I took it for a test flight and the copter had noticeable motor vibes on launching, but it flew responsively. I think though that my starting PIDS felt better than the ones applied by ATUNE. It eventually triggered a battery failsafe and you will see in the logs the failsafe and RTL being triggered. I switched manually to AltHold, then back to PosHold and landed manually.
So the phenomenon witnessed during the autotune procedures were at least consistent between roll/pitch axis tunes, but never the less not what I expected.
Hoping this info and the attached log is helpful to the devs to further perfect the autotune process and maybe check to see if the behaviours witnessed were actually issues, or intended behaviour etc.
Cheers, Paul
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