I'm hoping to go for a test flight tomorrow with the new 2.9.1 firmware. Before I do however, I would like to confirm a couple of things.
Having upgraded from 2.8.1 to 2.9.1, I notice that some of the PIDs are significantly different (higher) in 2.9.1.
Now, before I launch, I would like to ensure nothing unexpected will happen. Do i leave the PIDs as they are in 2.9.1, or drop them back down? I presume the ones that are shown are the default values ?
I have highlighted the ones in 2.9.1 with the main difference in red.
Is someone able to cast their eyes over the setttings and confirm all is OK or not for me please.
Also the INS_MPU6K_FILTER is 0 where it suggests it should be 42 for ArduCopter. Therefore is there anything else I should look at in the advanced PIDS that 2.9.1 has defaulted on ?
For info is a 3DR Hex with 2.5 APM and 880kv motors with 12" props.
Many thanks,
Steve
Replies
Oh yeah the filter value of zero just means default (that happens to be 42hz)
If you have a vibe free frame (enable raw logs, hover, look at raw_Z_acc data - it should be as smooth as poss, around the -10 mark (fluxing ideally not more than +-3 in either direction) then this filter will be fine.
But if your vibes aren't great just drop the filter value to 20 (probably will be the default within the next release or two anyway)
Hi Steve,
Yes the inertial nav on the z-axis that is now enabled in 2.9.1 requires very different throttle and alt-hold params. The new defaults should be bang on, but just to ensure you are not over tuned for your first flight you could drop the THROTTLE_ACCEL_P to 0.5 and I to 1.0 (keep a 2:1 ratio)
The other params will adjust the 'feel' of the throttle, but won't have adverse effects. If you use the old throttle and althold params you will find that the throttle response in alt-hold and loiter is very slow and delayed in it's reaction. So, yeah, use the new ones.
The new loiter params should work fine if you are using a ublox on Mtex with v1.9 on it, if you are using an old 1.6 mtek you may experience toilet bowling, and will have to drop loiter_rate_p to closer to your old value.
As always I'd recommend droppin rate_p to about 0.12 for your first flight, then tune it back up if you can without oscillation.