attached is the log file of two autotune flights for roll and yaw axis. The autotune process of yaw was automatically terminated after some time without RC input and the parameters were not saved. What could have been the problem?
One flight before the roll axis was tuned. The result of P and I seems very low. Immediately after the roll autotune the Copter flew very satisfactorily. But it seems as if the stability on roll decreases with increasing flight duration. It reacts very sluggishly to light wind and swings up.
Without knowing more about your aircraft there is not much specific advice I can give you. I can see that you have not set up your aircraft parameters before doing your autotune. In particular you have not set the MOT parameters. In the MOT parameters the voltages are what gives the mixer the information to compensate for low battery voltages.
I wrote this page to take you through all the settings you should consider if you want to get a good tune from your aircraft. It is written as a step by step guide. As you are already flying well enough to do autotune you should be able to go through and fix any of the parameters you have missed. As always be very careful on your first take off after changing tuning settings.
The link was actually new to me although I thought I knew the documentation by heart I always skipped the MOT parameters because the results were usually very good.
The aircraft is very different in terms of roll and pitch moment (similar to a helicopter) and offers a large area for wind on the roll side. The resulting undesirable effects have to be compensated as good as possible with optimal parameters. I will do the testing.
@Leonardthall thank you very much for the hint!
I have neglected the MOT parameters so far because we mostly fly with lipo batteries. This drone has a Li-Ion battery, the voltage range is much wider here. After we adjusted the MOT parameters, another autotune flight was very successful!
To put this in perspective, and to explain why it is so important to set these parameters for LiPo batteries. For a standard LiPo battery the gains of the PID loops will increase by up to 60% over the flight to account for battery voltage reduction. As I am sure you can appreciate this is even higher for Li-Ion batteries.
I wish I was any good at programming - I’d make a wizard for initial setup in MissionPlanner for setting of battery type, number of cells, prop size and whatever else is appropriate. This would have to lead in to voltage and current sensor calibration.
And some of these tuning parameters could get auto-populated with values, with caveates of course.
I know a wizard probably wont suit all craft, tuning would still need to be done, but it might provide a good starting point.
Yeh, I have been planning to do some default parameter list for small, medium and large aircraft. Not as extensive as what you are talking about but a start.
It’s still on my to-do list to get you some more information about small copters. I’m building a couple right now, so will better know exactly what parameters need to be changed.
It seems like it’s mostly just the filters, if you want the bare minimum. Default PID’s were good enough to get me flying for auto-tune once I adjusted the filters.
But, there are a bunch more parameters that make sense to change too, if you want a more comprehensive set of changes.
I always skipped the MOT parameters because the results were usually very good.