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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Impressive bunch of work!!!  thanks dev team!

I fly from 320kv's (these swing 15inch carbon props) up to 2200kv on a micro quad (with 4" props).

 

Its sort of a balancing act, and includes looking at the type of battery you are using. For example with 4s batteries I would tend to drop a prop size, so 850kv motors i use 8 or 9" for 4s, 10" or 11" for 3s, and the performance will be very similar, even flight times are similar.

 

Then i have the screaming machine that uses 4s and 11" props, on 880kv motors, i can't tune this as highly as it's overpowered, but it is oh so fast :)

 

But defo as cybercrash says the lower the kv and the bigger the prop the more efficient the system becomes, but it starts to also get more expensive as you will start to need big expensive props and batteries.

 

Thanks for the info, Dave.  I am becoming aware that there are two types of flyers which is one of the reasons that the advice on the forum appears to be all over the map.

Correct me if I am mistaken, but it appears that most of the forum participants want to tune their copters to be hummingbird-agile on the threshold of instability.  (In combat aircraft, the less stable the craft, the faster the control response).  Others, like me, want a slow, heavy-lift stable platform to carry cameras to altitude.

So which profile are the default parameters closer to?

Does it have to be stationary when leaning or is just holding it 90 degrees tipped enough?

Jiro: Absolutely. That will be in the MP when 2.9 is released to the public. 

If you use 3dr frame and 850 motors, 3S battery and 10" props the default params will be pretty much in the middle.

 

If you then stuck a 4s battery on or more powerful or faster motors you would find yourself gettin more highly tuned, possible shaky. Conversely if you just swapped out the 10" props for 8" and stayed on 3S you will find your self undertuned, less agile to control sticks, but probably quite a bit smoother for aerial photos.

 

For big octos with expensive cameras i under-tune slightly to keep things smooth. For FPV, fast flying, acrobatics etc i tune it as far up as i can whilst still happy with the performance, often tolerating a bit of shake for FPV as i do quite a bit of indoors scary stuff and it needs to be quick as it can :)

Hi Joe, thanks for the info :-) when you say lean the copter ? how much are you having to lean it over?

"how much are you having to lean it"

'Til the engine runs rough - sorry, inside joke among the pilots here.

and here was me thinking it was until the props cut you (only joking)

Will using levels, plumb bob's etc. increase the effectiveness of this calibration?

Gerrit,

     stable is important.  It will take a number of accelerometer readings but if you're holding it in your hand while doing this, it's likely it will be moving a bit.  It may work well enough but I always lean it up against something while doing this calibration.

Here's a video demo of how to do the accelerometer calibration.  You should try and keep it stable but it actually doesn't matter if it's perfectly level, or perfectly on it's left side etc.

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