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!
After a few weeks without flying I upgraded from 2.5.3 to 2.5.4 yesterday. My last flight on 2.5.3 was very good. My first flights on 2.5.4 have shown sudden rapid changes in pitch and roll (seen on log) while in slow hovering flight, enough to crash depending on altitude (1 to 2 meters there's sometimes enough time to recover).
I realise that this may be motor brownout and the new version could be coincidence.
Flying APM2 standard 3DR frame 880kv motors, 12x4.5 props. Default PID except for Rate P which I have reduced to 0.10 (in flight tuning on 2.5.3) - have yet to tune anything else.
Could this conceivably be software / PID related?
Is there any way to see motor brownout on the logs? Do the default logs include APM output to the ESC's or user control input? The roll/pitch input on the current logs certainly don't match the sudden pitching of the quad.
I have attached a log of this mornings very short flight, the major roll/pitch is clearly visible.
Then also a general question on logs. When is a log started and ended? Is this determined by throttle min and max or by the arming of the motors?
Did you do a new setup after upgrading? It's important to do the compass calibrations (Live Calibration recommended), too. The compass is now a much bigger part of attitude calculation.
Logs are started at power-on, I think,
Yes I did. Can this affect Roll and pitch though? Would have thought only yaw?
Yes, the compass is a three-axis device. Can you try flying again with the default settings? It's working great for me on that same frame.
ok, recalibrated the compass again and did a test flight. Displayed compass heading seems a bit more accurate than it was - changed about 15 degrees
Flight more stable. Not seeing the sudden roll/ pitch changes anymore, but sudden increases / decreases in thrust to all motors.
In my test flight I had a sudden loss of power to all motors (say about 0.25 seconds, so a quick drop and correction, and the drop in motor power is audible. I then landed the quad, and as I was throttling up to take off, there was a sudden increase in throttle which hopped the quad off the ground about 10 to 20 cm, then returned to my input level. This is better than it was as the quad at least remains level
In six to seven minutes of flight this happens maybe 3 times or so.
Have attached logs. Ignore the sudden roll at the end of the log. Battery ran out on takeoff!
Also flew a bit in alt hold on this test, seems to be ok, although I did see a slow decrease in altitude on one test.
A good chance your radio connection has a faulty wire.
Thanks Jason, will check. I assume you mean server wire between receiver and APM2?
Do you have an xbee? If you do, can you make sure the wiring from the xbee is far away from the receiver and radio input wires? Also if you have a ferrite ring can you wrap it around the xbee cables?
alternatively can you try disconnecting your xbee and see if the problem persists?
James: Are you using an Xbee or 3DR radio? We've had occassional reports of throttle drops and cutout in the past, and they've usually turned out to be due to Xbee interference (solved by moving the Xbee further away)
Hi Chris, Randy.
No Xbee or other add-ons as yet
Hitec Aurora 9 radio
Replaced servo wire between receiver and APM2 (Channel 3 - thrust) and seems to have helped. Completed entire test flight without any drops in thrust. Thanks for the help, will let you know if the problem occurs again.
Just goes to show it's often the simplest things!
Thank you for the tip. I am new to quadcopter and have loaded the new version of apm planner.
P.S. I should read all the the tips on the forum more often. thank again