Thanks to help from Sami Finnila and Wesley Chuen we've found an issue with the default MPU6000 accelerometer scaling in some of the recent APM2 boards shipped in the last month or so. You can find the original discussion from Sami here.
Internally we use "DCM" to merge the gyro and accelerometer values together to calculate attitude. With the recent boards we are finding the accelerometer values are 2x as big as they should be which leads to an inaccurate attitude estimate. It's apparently possible to fly with this misconfiguration but it at least makes "the leans" more common (you can recognise "the leans" by your copter requiring more and more manual roll or pitch to keep it level as you fly).
This patched version is being called 2.5.5-Beta and is in the downloads area. After a short testing period (maybe 24h ~ 48h), if all goes well it will be available in the mission planner.
We're still working on the next official release 2.6 so we haven't included any improvements to flight dynamics in this patch except Adam's "Retro" loiter. This uses the ground speed directly from the GPS instead of calculating it using lat/lon position. You can enable this by setting the "RETRO_LOITER" parameter to "1". BTW, it's "retro" because this is the method used in the popular 2.0.49 version of Arducopter.
Feel free to post comments / issues regarding this patch release in the discussion below.
If you have recieved an APM2 in the last month, please try the test shown above:
Next just roll and pitch your board a bit and attach your tlogs below. These logs can be found in your AP Mission Planner's log directory. On a windows machine you will likely find a recently updated file here: C:\Program Files (x86)\APM Planner\logs\YYYY-MM-DD HH-MM-SS.tlog
Thanks for your help.
When will be DMP available!!!!
I still remember
Or I bougth something that promised what can not be delivered??
I think with DMP all scaling and no sense problems should be gone.
For a board that flight absolutelly not better than a 50USD MWC I would like to have some extra features...
Well, last time I checked, this was an open source/community project, so if you programmed as fast as you type those exclamation marks ... :)
DMP released has nothing to do with open source or programming skills.
I can also collaborate with APM open source testing and reporting bugs I can documents as good as possible. An example of it was AHRS hanging on GPS first lock and some code bugs like issue 356.
DMP software is ready realease but some restrictions from AD prevent from that.
restrictions from AD ? who/what/why ?
Who: Sorry, Invensense..
What: read previous posts
Why: as above
ah so !!! :)
Yes, apparently there's an issue where we need to use some code in the main APM code to make the MPU6000 do it's thing. I think that code would come from Invensense. But they won't allow us to release that code in an open environment.
So it's a bit of a pickle.
ouch - why do we do business with that company then ? - are they really that good ?
I don't have any opinion or answer on that. It's disappointing, yes, but I do not have enough info to know what's really going on.
But as far I can see in the web, there is a lot of people that has this feature working without using propetary software from Invensense.
What would be then the problem of using this code? I paid the money for the chip, if I can develop my own software for using all features in the chip why shouldnt I be able to do it?
If not invensense should have prevent us for doing so using some kind unbrakeable encriptation to access this feature, or?
@Andke !!! :-D
With DPM the difference would be great..
I believe some of the developers have access to the code? but cant release it as open source.. :(
There has to be some way around this? such as signing a form or something? as you do when you download software??
Yes, we have the DMP running privately. It works very well, although not all that much better than a well-tuned DCM. The main advantage is that frees up processing power to do other stuff, like self-learning algorithms. Not a game-changer, but a nice thing to have. We're in production discussions with Invensense about releasing the necessary code open source and I hope we'll be the first to be able to do so. I hope to have more news in a few weeks.