Version 2.5 of the ArduCopter code is now available in the AP Mission Planner and in the downloads area!
The default PIDs are optimized for a 3DR/Jdrones quad with 850 motors and 10" props. If you're using more powerful motors/props, start by turning down Rate Roll P in 25% steps.
While some testers have reported very good flights with the default PIDs, some have reported that this release is a little "sharper" due to the DCM improvements and have found they needed to:
reduce stabilize P by 10% (i.e. 4.5 -> 4.2)
reduce stabilize D by 30% (i.e. 0.15 -> 0.10)
increase rate D from 0 to 0.001
Tuning loiter can be tricky. Refer to the discussions which will appear below for more community feedback on what parameters work best.
Please post your feedback in this discussion. For enhancement requests and bug report, please add them to the arducopter issues list. When possible please include logs (tlog and/or dataflash) and tell us whether you're using APM1 or APM2 and what version of the software you're using (presumably 2.5 but tell us anyway!).
Thanks for this release go to the developers (both in the core team but also those who have provided bug fixes through the issues list) and also the community members who participated in the previous release thread and provided some great detailed information in the form of issue reports and logs which allowed us to nail some bugs!
@lars-- I had the same thing happen to me twice with my X8 550 frame. I was unfortunately in high mid flight destroying my frame completely, s soon as rebuilt and able to download logs I will post. Is this a problem others are having? I have been away from the boards a while...
You can level the copter with a long left yaw movement (with 0 throttle), maybe you were trying to disarm and you made a level change.
Lars, have you set the CH7 in your TX assigned to AutoTrim?
Many inadvertently do this thing, and they do not then realize that their CH7 on the TX is reversed, and assign it to a switch with flying with AutoTrim always enabled.
However do not recommend the use of the ALT HOLD mode, rather Loiter used because in any case have the opportunity to adjust the altitude during the flight.
I have read of many who have had this problem by switching these two mode during flight, I personally do not use ALT HOLD and then I never happened.
I recommend this procedure to the perfect level of the quad:
1) try to have a good static center of gravity with your quad, if necessary move some hardware (like LiPo) to have a good balance, this is to prevent the motors/esc are in a different way
2) put the quad on a level floor and hit "LEVEL" on the planner
3) assign CH7 to "AutoTrim" function in the planner and to a switch on your TX, and check when you mode the switch if the led on APM begin to "rotate", normally blink
4) flight your quad in windless condition, switch to AutoTrim during flight and try to mantain the quad levelled, giving little stick correction and then back with the stick in neutral position each time, to see if it remains firm enough
5) when you are satisfied with the result switch to "AutoTrim OFF", land and disarm the motors, now your quad is trimmed
6) remove the CH7 "AutoTrim" function from the planner and write the parameters
PS: don't touch the trim and subtrim in your radio, must always be in a neutral position (central, zero).
Thanks for your active interest in my project.
Ian - sorry for your crash. Looking forward to se your frame reborn and in air again.
Marc - Yes, it might be so that I pressed the stick down-left too long time, although I don´t think so.
I have a Graupner mx-20 with six fight modes. Its CTRL 6 (pot) is connected to Ch6 on APM2. The Planner shows how the flight modes changes:
Switch 8 Down, CTRL 9 Down: Stabilize
Switch 8 Down, CTRL 9 Middle: Alt Hold
Switch 8 Down, CTRL 9 Up: Loiter
Switch 8 Up, CTRL 9 Down: Stabilize, Simple
Switch 8 Up, CTRL 9 Middle: Alt Hold, Simple
Switch 8 Up, CTRL 9 Up: RTL
I have kept Switch 8 Down so far. During the flight I switched from Stabilize to Alt Hold and in order to go down I switched back to Stabilize.
By the way, I plan to buy my 2nd APM2, just in case... The first one seems to be OK even after the latest misadventure.
Couldn't help notice your STAB_I at 0.100. Leave it at 0.000 and instead use the RATE_I at 0.010 (both on Pitch and Roll). Also you may try to reduce a bit your STAB_D to 0.100. Try this to see if it gets more controlable. STAB_I to me was giving some twiching in mid air. Hope to see you in the air again soon.
I've switched between alt-hold and stabilize a lot of times, never had an issue with it.
Think I'll pay special attention when using alt-hold next time...
Marco, can you also fully test this mode? If alt-hold has a bug, then it's better that people know about it.
In theory there is no inherent bug with ALT HOLD, but I never tested this mode with ArduCopter.
so as soon as you switched to alt_hold? This happen
I started in STABILIZE. During the flight I switched to ALT_HOLD. I flew for a while in alt-hold mode. My wife ordered DOWN and then I switched back to STABILIZE and slowly took down the throttle. During those last seconds of the flight the hexacopter tilted over heavily and went down.
I've just filed an enhancement for simple mode.
Hopefully the developers can make super simple mode available at all times, not only when the copter is more than 20m away.
I think super simple mode is the only way to really save your multicopter when losing orientation and thus control.
I'm aware about the gps inaccuracy/limitation.
I'm nog going to use super simple mode 3m away. But I might use it 8m or 10m away.
Anyway, 20m away is too far imo.
Btw, even if GPS is inaccurate, pulling back the pitch stick would have to keep the copter around where the pilot is, recalculating home constantly even when it overshoots.
It's not that bad if home position is not that accurate.
GPS inaccuracy can't be more than 10m on each side, right?
Normal simple mode won't do that. Keep pulling back the pitch stick is not going to make the copter come back home, in the end you're going to loose orientation even more, finally resulting in a crash.
And I'm not saying everyone has to use this. It should be an option for people who are aware of the gps limitations and do still want to use it.
As I mentioned before, the code is, as of 2.5.4, 10m not 20. Changing that value yourself, provided you don't mind compiling (which is pretty straight forward), is one number in one file.