Arducopter 2.8.1 is now in the mission planner and in the downloads area! Remember to do your MP configuration again after loading this code, since it erases your EEPROM and sets it to the new defaults. 

Note: Issues with APM1 user's level feature not working are now resolved.  If you installed 2.8 we highly recommend you upgrade to 2.8.1 as 430 extra bytes of RAM have been freed up which reduces the chance of memory corruption (although we haven't seen any cases of this on the APM2 at least) .

Note #2: this release has not gone out for Traditional Helicopters until they can be tested fully.  Flip and Toy mode have also not been fully tested.

Improvements over 2.7.3:

  • Improved ACRO mode (Leonard Hall)
  • Improved stability patch to reduce "climb-on-yaw" problem (Leonard, Rob Lefebvre, Randy)
  • Rate controller targets moved to body frames (yaw control now works properly when copter is inverted) (Leonard/Randy)
  • Less bouncy Stabilize yaw control (Leonard)
  • OpticalFlow sensor support for APM2.5 (Randy)
  • DMP works again by adding "#define DMP_ENABLED ENABLED" to APM_Config.h You can also log DMP vs DCM to the dataflash by adding "#define SECONDARY_DMP_ENABLED ENABLED" (Randy)
  • Watch dog added to shutdown motors if main loop feezes for 2 seconds (Randy)
  • Thrust curve added to linearize pwm->thrust. Removes deadzone found above 90% throttle in most ESC/motors (Randy)
  • More timing improvements (main loop is now tied to MPU6000s interrupt) (Randy)
  • GPS NMEA bug fix (Alexey Kozin)
  • Logging improvements (log I terms, dump all settings at head of dataflash log) (Jason)

 

Bug Fixes / Parameter changes:

  • fixed skipping of last waypoint (Jason)
  • resolved twitching when no GPS attached (Tridge)
  • fixed loss of altitude if alt hold is engaged before first GPS lock (Randy/Jason)
  • moved Roll-Pitch I terms from Stabilize controllers to Rate controllers
  • TILT_COMPENSATION param tuned for TradHeli (Rob)


Code Cleanup:

  • HAL changes for platform portability (Pat Hickey)
  • Removed INSTANT_PWM (Randy)


As per usual PIDs are optimised for the 3DR/jDrones quad with 850 motors and 10" props. If you're using more powerful motors/props and are seeing bad flight behaviour in stabilize, start by turning down Rate Roll P in 25% steps.

Please note that on this release we've moved the Roll and Pitch I terms from the Stabilize controller to the Rate controller. There's some evidence that says this can lead to flips on take-off if you move the roll or pitch sticks around as you take-off so we recommend you leave these sticks in the middle until you're in the air.

Please feel free to report issues you find in the discussion below and/or add them to the issues list.

Thanks and enjoy!

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Something to check is the radio calibration page in the MP.

Without manipulating the sticks of the tx how much are the values of each channel changing?

 

I did radio calibration many times before I the rx change, and first thing after.

The values in the radio calibration page in the MP was solid - at least on the bench without power to the motors.

There was something happening when vibrations and or electrical noise came in to play. 

The quad was an APM 1.4 1280 at the time (now updated to 1.4 2560) on stock jdrones frame, 850kv motors and jDrones 20A ESCs (now flashed with simonk and 10x4.5 props. I did not manage to get the logs to work at the time, so unfortunately I have no logs :(

No problem Stephen! ;)

But now I think I can't help you, I don't know what are the differences between those 2.7.3 versions :/ sorry!

Thanks Andre - this was a bigger help than you realize.  Unless someone has a coxed to translate, I'll assume the highest one in the list is the latest.  Besides, it's only a fallback position *if* needed.

Steve

I would also assume that the highest one on the list is the latest, I think that those numbers are related to the MP versions, but is just a thought...

I know, but the problem is, that what you consider "steady" may not be steady for the APM.  When tuned up, it really will resist even little movements quite strongly.

Manfred, the test flights went really well.  Only problem was a crash at the end which was the result of a combination of pilot error, and my ESC code which just isn't a great system and I'm going to fix.

Thanks U4.

I have now changed all ESCs to high timing.

I'll be testing it in the morning with video so will report back :-)

Thanks again for your assistance.

Hi!

Thank you very much for making such an effort to help others with PID tuning. I am also no expert in these things but i did a lot of tuning mwii PIDs on different copters. Starting PID tuning from the "D" is a really weird approach in my eyes.

Normally you would start with low I and D (for example 0 - depending on flyingskill) and increas P till oscillations appear - than back off a little (not factor 0.6 like often suggested). Than increase the I until it holds angle sufficient and no further oscillations occure (P&I work hand in hand and both can produce oscillations) then increase the D until it feels to sluggish or problems occur. Starting with D is out of the question for me because: 1.: The D is trying to predict errors. So it takes errors from the past and projects these into the future. (trying to win the lottery...) 2.: The D is the most sensitive part to vibrations/errors. After tuning P & I you can use D to iron out remaining oscillations. Whatever, just my observations from mwii pid tuning and reading pid - wiki etc. The "P" is the most decisive part of any PID controller.

BTW: NEVER EXPECT INDOOR PIDS TO BE OF ANY USE OUTDOORS. THEY WILL BE TO HIGH (ESPECIALLY P). - And vice versa

So long

Kraut Rob

I hope your Heli hasn’t been damaged too much. I know how it feels.

Really great news that the test flight went really well.

I know you will fix the rest.

Many thanks for doing it.

Yeah, mechanically it's not too bad. Flybar, blade grips, landing gear, main gear, I'm not sure what else yet.  Maybe the blades, one of them looks to have a crack near the root.  Not something I'm inclined to take a chance on...  

I was actually planning on yanking all the electronics off of this one and putting them on my new 550/600 FBL Frankenstein heli anyway.

But the unfortunate thing is the speed control popped.  Not only that, but Hobby King is out of stock of all the ones I like. :(

I had this same issue, the throttle wooed kind of pulsate and grow on its own. but I went back through and did a  Manual ESC calibrate, with special effort given to doing the throttle movements Exactly the same. Then I took a my programming card and made sure every esc was exactly the same, and that did the trick.

IF a else fails, try erasing your APM and starting again with a clean sate.


Having a programing card only costs you a few bucks, but it makes it soooo easy to make sure everything is in sync.

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