Jason is travelling this week, so I'll take the helm for the next software release post.
UPDATE: the motor remapping thing was confusing everyone, so we took that out and returned to the regular motor mapping. That means that APM 2 users with Hexas and Octos should wait for the next version. APM 1 users should be fine with any frame.
NOTE: Hexa and Octo users: there have been motor mapping changes that may affect you. Please don't upgrade until we can update the documentation to reflect the changes. This should happen by the end of the day today (Feb 1).
ArduCopter 2.3 is now available in the Mission Planner. This is the next revision of the ArduCopter 2.2B6 code, which is perhaps the most tested code we've ever released (1288 comments in the thread!) and certainly in my experience the best code, too.
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 (default is 0.14, so start by turning it down to 0.1. In general tune PIDs in 25% steps).
Now that we've got solid code out there, we can turn to collecting suggested gains for standard frames, and a better guide to how to tune PIDs for your unique setups.
Here are Jason's note on the latest changes (mostly from 2.2B6)
A dampening term called STAB_D has been refined. A D term for all of the Rate based control loops has been added based on Igor's work. Landing for Baro and Sonar has been refined based on JLN's work. A slightly new approach to Loiter and Navigation is being used to try and linearize the pitch and roll for rate control. It tends to use lower gains, yet has a more assertive response in the air.
STAB_D : This is the gyro accretion dampener. This can remove small wobbles during sharp changes in angle commands. Making this too high can have a negative effect in performance and add a memory effect that can cause temporary loss in control. The in flight tuning is ranged so you are just below that effect.
If you haven't noticed before the control loops are in two stages. The first is a PI stage that converts some sort of position or angle error into a desired rate. These generally do not need to be tuned. They are more of a user preference on how fast you want the copter to perform a motion.
The second stage is the actual PID loop that needs to be tuned for the copter. This converts the desired rate into a motor command of some sort. I added a D term based on Igor's recommendation to the PI's for each rate controller. These should show up soon in the mission planner for the release. I cannot give you a concrete answer for how to tune the D terms, because they each depend on their function such as alt hold or loiter, etc.
Still, the absolute most important term is always the Rate_P term for each loop. Start tuning here.
The default PIDs are in the what flies great for a stock jDrones/3DR Quad with the purple motors in X mode.
Note the Mission Planner does not yet highlight these D terms on the main tuning page (it will soon), but you can find them and modify them on in the Parameters list.
Autolanding should now work well (see video above) and the Tri servo issue is now resolved.
The code should now compile with Arduino 1.0 (thank, Randy!), but remember that you need to use the "relaxpatch" version of Arduino in our downloads section.
[Update: we've reverted the below. See update at the top of the post]
Important for Octo users:
We've changed some of the motor orders for some more exotic airframes. We'll be updating the docs on the Wiki in a day or two to reflect this. Pat Hickey explains:
As before, the hexa plus APM2 motor setup has changed from the ordering [1, 2, 3, 4, 5, 6] to [ 5, 6, 1, 2, 3, 4 ].
The Octa V layout for APM2 is:6 42 58 13 7Motors 1 through 4 spin clockwise, and 5 through 8 spin counterclockwise.
Does anyone know why default parameters in 2.3 have Rate_D as 0 for roll and pitch but 0.002 for Yaw?
Just trying to make some logical sense of it.
Thanks in advance!
It is really not that much sense, Rate D is to be set for your quad, you might as well leave it to zero everywhere, although I believe that a value of 0.005 does not bring any problem on any configuration.
We are studying a lot of improvements for the next version out, you have the patience to wait a bit, the results do not miss (I hope).
This waiting is synonymous with frugality in fixing the problems and in improving the situation in general.
Marco, thanks for your reply! I'm testing it on my tri-copter, and let me tell you, it absolutely hates any kind of Rate D on yaw .... also Stab D doesn't seem to have any positive effect either ;-( I guess i'll keep trying and awaiting the next version out....
As I read back through the forum looking for hints to get mine better tuned it seems obvious many are having problems with the PID settings for 2.3 and particularly for loiter and RTL. The default is suppose to be the starting point and modeled around Jrones Quad and 3Dr quads.
Wouldn't it be possible to work out table for the PID to scale up for larger rigs or down for smaller rigs by calculating the power to weight ratio and then a scalable adjustment for the PID default for those? eg, Kgs thrust versus rig weight etc.
Hey again everyone, trust you are all well and flying!
Just a quick report from our latest flying 2.3. Just got back from a 2 day film shoot flying our octo and once again, it performed perfectly, without a single hint of a issue. We flew for 2 FULL days, in an average temp of about 35'C, it was super hot! Some hot glue of our octo even melted but the system worked flawlessly. I loaded 2.3 and did one or two very quick indoor test flights before packing the van and driving 5 hours to the shoot so was a little nervous as to wether it would keep up as the previous code (mostly .49) has, and it did.
Just a big thanks again to all the developers and guys working hard on this code, if anyone needs any advice on running Arducopter on bigger octos, feel free to get in touch, any time!
Hope to load some behind the scenes video clips we took soon!
Hi Duran Dev,
Nice to know !! could you post your settings and Octo characteristics??
Oh yessssss.... :-)
My octo is ready again for the battle... :P
There's some fix available in the GIT, testing this evening with AeroSim and Friday in the reality.
Hey Marco. Glad to know :) I've been grounded for the last week or so due to medium to strong winds. However, I would like to remeber one thing : I was flying my quad powered via the first ESC. On my latest configuration, when I had the quad powered via USB, everything worked, but when I connected the LiPo without USB, I had no GPS. I thought the BEC from the ESC feeding the board could have a problem and not feeding it right, so I powered it via a UBEC and worked fine. One thing I read in the UBEC specs was that it might cause receiver interference and should be at least 5cms away from the RX. I don't know if you guys who have been experiencing radio problems are feeding the board via a UBEC, but if so, have this in mind.
Hi Rui, UBEC is linear or switching?
yes that true Rui,, its good idea to put a graphite choke on the wires of the ubec. Most of the wires on mine I put a shield foil around to reduce any rf interference.