This is a work in progress. I've tried to address some fine tuning and performance issues.
Denny R. had made a comment about the inertia of bigger props causing issues. I've added a low pass filter to smooth the positive acceleration of the props to see if we can get at this issue. It may require tuning up Rate_P for a few folks, but I saw little issue in multiple flights.
Crosstrack had a small math error that decreased the resolution of it. I've fixed that and upped the default gains to get better tracking.
Made WP hit radius 1 by default. even 3m is too much for quads. (If you pass a WP you will move on to the next)
The Loiter method is tuned a little better by default, and now uses GPS offsets when flying less than 1.5m/s. Code experimentation will continue on this front. Thanks to Emile and afernan for their help!
A fix in the Z Accel startup was added to get an averaged result.
Added the ability to enter Loiter with Optflow enabled. - still a work in progress, not for everyday use just yet.
This alpha is on GIT now and is for user's who want to test code. As always, you need to use the "relaxpatch" version of Arduino you can find in the downloads section.
Update: We've found and patched some small type bugs in the latest and updated some GPS drivers in the Library. Be sure to pull the latest code and check http://apm.tridgell.net/ for the status of each build run against the SIL sim server.
I pushed a version on to GIT that addresses a number of issues.
- the low speed GPS XY calculations were incorrect and have been fixed
- Nav_Rate I term has been removed in loiter control - it's too easy to get two iterms working out of phase
- A second derivative has been added to Roll and Pitch. I found it removed wobbles nicely - Can be adjusted in the planner as STAB_D with a default of .25 (just enough)
- Smoothing has been applied to the motor commands in a way that really quiets down the alt hold pulsing without much effect on latency
- Yaw now has a dynamic constraint and I've upped the yaw gain.
- The motors output now have an LP filter on them so that the accelerate just a tad slower than the deceleration. This is a test to see if it helps big Octo's and Hexa's
- The Rate_I term is now zero'd for first five seconds after takeoff to keep balance.
- Loiter gains are lightened up a bit
- Nav_Rate_P is lower to remove back and forth sped related hunting in loiter
- Compass is enabled by default
- New I2C Library now included which should solve I2C related lockouts
- optflow is still a work in progress.
This update is based on flights today in a very windy environment.
It occurred to me that we're handling the WP nav I terms incorrectly and I reworked the WP navigation to share the same I terms from the Loiter. Even though they use different error input, etc, they turn out to both deal with wind in the same way. I have not Flown WPs with this new code, but heavily tested it in the sim and It's really rocking in hard wind. Transitions from Loiter flight and Nav flight are very smooth. Please let me know if you have luck.
This is a quick patch based on a bad crash Marco had. My theory was an I term that built up during wind that needed to be reset, but wasn't. It's a corner case but It bit Marco pretty bad. Please re-pull if you have R4 running to go to R5. And please, please be careful. This is alpha code not for general testing, but for development. Don't fly it on anything you would feel bad about crashing.
Update R7:Added an auto-land timer for RTL. If you don't change modes for 20s after the copter arrives at home, it will begin to auto-land. If you have failsafe and no GPS, you will immediately begin auto-landing.
Minor tweaks and cleanup
Made climb rate controller for landing universal for all altitude changes
Updated Loiter controller - Works great in the sim, thanks Afernan.
Ok, see, I know very little :-)
I'm not an expert either. I could be wrong, but I'm pretty sure that's how it works.
for which we have the APM1 1280, you can make a list compiled version to load from arduino?
to download from here?: http://code.google.com/p/arducopter/downloads/list
Is there a lot of people like me who do not know what we have to eliminate to enter into the 1280
The R5 that was about 2 pages back in a zip file, still fits on a 1280......
Pleasure, oh, you need to use the "relaxpatch" Arduino to compile and upload.
Was mentioned and a link given somehere back on this discussion.
Yes, that relaxpatch version of Arduino is linked in the original post above.
Test of the firmware ArduCopter v2.1.1 R5b in HIL mode on X-Plane v9.70
I need to try this in Xplane! cool!
Jason, could you offer some advice on PID tuning for R5. I switched from stable to loiter and my quad immediately gained about 15 to 20 feet of altitude and then immediately lost 20 to 25 feet of altitude. The whole process of PID tuning has basically been a guessing game for me. Could you please offer some advice on how PIDs for Loiter, Throttle Rate, and Altitude Hold should be changed based on observed behavior? I would be extremely grateful.
The Alt hold mode includes the ability to rise and fall based on throttle stick position. You may have not had your throttle in a good position to start with causing you to rise.
Altitude Hold defines the desired climb_rate for altitude changes. You really don't need to change this.
Throttle Rate is the amount of throttle to apply to adjust for your climb_rate. If this number is too high for your motors, you will overshoot and start to oscillate around the desired set point.
The iTerms should not really be bothered with. There is only one iterm active and that's Altitude Hold_I.
It's used to adjust the throttle based on battery pack voltage drop and it takes some time to wind up.
Hello everyone! One very important thing: do not use absolutely the ACRO mode with this release and with others over 2.0.50 (including), as has already written Jason is there's a remote possibility that it may take over a problem in flight, my heavy octo sacrificed himself for others to test this thing, with a loss of over 1000$ but making it in the future you save a lot, ensuring a more secure future for your.
The incident is luckily documented, logged with telemetry and filmed, that's part of my cooperation with DIY Dev Team, although I would prefer not to happen (LOL).
I waited to alert the community because we wanted to make sure the problem was not an isolated case but now Tridge, with a thorough and surgical analysis he understood what happened, and all we are infinitely grateful.
No other mode of flight is afflicted by this problem, if you do not use ACRO for now you can fly much safely.
This anomaly can not be present if you fly with all the simulator, but just in the reality and for a number of specified steps, although it is quite unlikely but not impossible.
All future releases will be fixed from this bug/issue, Jason clearly write it in the news.