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!
We're looking into your issue. I can definitely see that your throttle is falling immediately after you engage altitude hold..the question is why..
So the issue is your THROTTLE_TRIM parameter is too low. After an version upgrade all your parameters are reset to the defaults which is 350 for this parameter. It will slowly update itself if you fly around in stabilize mode for a while and maintain a somewhat constant altitude.
You can take a short-cut though and just go into the configuration screen of the AP Mission Planner and set it to 450 or maybe even 480. That looks like the value you need.
Thanks Randy, will try that. Noticed when comparing params to my previous setup that the THROTTLE_TRIM parameter was 423 but is 408 on the new. (I did a full erase before loading 2.5 then did full setup but kept all default params)
Also how do I get a more direct feel with minimal lag for throttle stick?
Set it to 450 and flew for a few minutes, had about a meter drop in altitude on switch, reconnected to the MP and it is now at 466.
Quick questions: so will it change by itself until it settles on the right value? And will that value stay set or will this happen on every flight?
It saves it to the eeprom when you disarm your motors so it should be ok in future flights.
You can see the effect quite clearly in the logs by the way..if you graph the "rc3 servo_out" value from the "CTUN" messages. this is the final output to the motors. Other important factors that contribute to that number are the "manual boost" column which shows what the pilot's input via the throttle stick is having (there's a large deadzone but above and below that there will be an effect on the throttle going out).
Also you can see the initial throttle_trim used when ALT_HOLD is engaged, it appears in the column just to the right of the MOD, ALT_HOLD message.
I had the quick drop on first attempt, i think because i went straight in alt-hold mode. After a quick hover all was fine.
It's probably wise to always disarm before you go sticking your hands anywhere near the quad. And that has nothing to do with saving parameters. ;)
Yes... Some thing happen to me... Broke all kinds of stuff... AMP2.....2.5...
stock param execpt Stab_P Stab_Yaw...
On large Tri-Copter
update... Set Thro Trim to 530.. then the alt hold worked again.....
Tuned Loiter but unable to stay in a 100x200 field... out of options..
I have experienced exactly the same problem. Mode select of ALT_HOLD or RTL both cause the Quad to fall to the ground. With same hardware in 2.4.1 I did not have this problem.
This was my first try of 2.50 today I have a LOG dump available if required by Development team.
Likewise I did not have the problem with 2.4.1, I also did not have the problem with v2.5 alpha from the git either so that is a bit strange. Anyway the fix is posted above by Randy, test somewhere safe, ie 1 foot off the ground :)
(BTW, mine has now crept up to 498)