ACRO bug (fixed in 2.9.1b): while doing flips in ACRO mode, if you switch to Stabilize while inverted your throttle will go to minimum. To regain throttle control you need to switch back to ACRO then back to Stabilize again (i.e. switch to stabilize twice). You never lose control of roll/pitch/yaw.
Loiter/AltHold/Auto/RTL bug: if you switch into these modes with throttle at zero motors will go to minimum until you raise the throttle.
Auto mode altitude bug (fixed in 2.9.1b): setting a waypoint altitude greater than 320m over home altitude may wrap around and instead be interpreted as a low altitude.
ArduCopter 2.9 is now in the mission planner and the downloads area!
The major improvement is we use inertial navigation to improve altitude hold. This increased reliance on the accelerometers means you must do some additional set-up before flying:
1. Perform the new accelerometer calibration in the mission planner (video). The auto-trim metho has also changed (video).
2. Add vibration dampening foam between your frame and the APM. Some suggested materials: DuBro, gel, hk foam.
3. If upgrading from 2.8.1, modify the throttle and altitude PID values:
- Increase your Throttle Rate P, reduce I to zero, increase D
- Increase Altitude Hold P, reduce I to zero
- Tune Throttle Accel P and I terms but try to keep P about 1/2 the size of I
Here is the list of major changes (a more detailed list can be found in the release notes):
- Alt hold using inertial navigation (Leonard, Randy, Jonathan)
- AUTO_VELZ_MIN, AUTO_VELZ_MAX parameters control the max climb/descent rate for the autopilot (cm/s)
- PILOT_VELZ_MAX controls max climb/descent rate for the pilot (in cm/s)
- Landing improvements (Leonard/Randy). Copter will descend to 10m or until an object is sensed with the sonar. Then slows to 50cm/s descent (speed can be adjusted with LAND_SPEED parameter). (video).
- Surface tracking with sonar (Randy/Leonard). Copter will attempt to maintain current distance from objects in front of sonar regardless of altitude. Only used in alt-hold and loiter, not used for missions. Sonar can be enabled/disabled with CH7 switch. (video)
- Failsafe improvements (Randy/Craig/John Arne Birkeland) including bug fixes, additional check for PPM encoder failure and implementation of battery failsafe. Set-up instructions are here.
- Mediatek gps driver accuracy improvements and use of SBAS [Craig]. Instructions on upgrading your mediatek to firmware 1.9 are here.
- Traditional Heli improvements (Rob) including (a) bringing heli code back into the fold, (b) enabled rate controller (previously only used angle controllers). (c) fix to rotor speed controllers - now operates by switching off channel 8. (d) allow wider collective pitch range in acro and alt hold modes vs stabilize mode (e) bug fix to allow collective pitch to use the entire range of servos
- Acro trainer (Leonard). Copter will return to be generally upright if you release the sticks in acro mode.
- ACRO_TRAINER : set to 1 to enable the auto-bring-upright feature
- ACRO_BAL_ROLL, ACRO_BAL_PITCH : controls rate at which roll returns to level
- Camera control improvements (Randy/Sandro Benigno): (a) AP_Relay enabled for APM2 (b) Trigger camera with CH7 or DO_DIGICAM_CONTROL command (c) Allow pilot override of yaw during missions and fixed CONDITIONAL_YAW command.
- PPM sum support for transmitters with as few as 5 channels (Randy/Tridge/John Arne Birkeland).
- Performance and memory useage improvements (Tridge).
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.
Special thanks to our testing team lead Marco and the dedicated bunch on the 2.8.1 release thread who put their copters at risk while testing the pre-release version. Some of their videos are here: 1 2 3 4 5 6 7 8
Please feel free to report issues you find in the discussion below and/or add them to the issues list.
Replies
Bit of tweaking advice please.
Loiter is holding initial position very well and perhaps I should not fiddle, especially as 2.9.2 will change things, but.............
Have been flying around in loiter and, I assume (after correcting the overshoot) it tries to hover over where the sticks were centralized? This sort of happens but it seems to slowly wander back to where loiter was first engaged. I thought by moving the sticks I was changing the lat/long of the loiter.
Is that how it should work? What settings will help that?
While I was distracted by FPV equipment the copter tried to reverse ‘home’ through a tree. It actually made it through unscathed, taking out a considerable number of twigs.
I wonder if alt-hold will trim a level hedge?
Can anyone explain acro trainer and if possible a video of it working. I have tried flying with it but not flipped yet. Will it self right if it is upside down and stick are let go?
Thanks
Once again, thanks to the dev team :-)
I loaded the latest code this morning into my APM1 quad, went through the acc cal routine, and the quad says it's pointing 10 degrees nose down in MP, every time
Fine, redid the cal routine 5 times, still the same ?
Reloaded the firmware, redid the cal routine, now it shows level?
Will fly later today.
Any pointers on deviation from the standard settings ?
I have one of the original quads.
Did 40 minutes of low level FPV flying yesterday, the Alt Hold is now fantastic because I have found with FPV it is sometimes difficult to judge and control a quad's height at low level.
In Alt Hold as long as one doesn't accelerate too quickly height is maintained very well, if one accelerates too quick the quad drops by about 1-2m before recovering.
RTL and Loiter also great, lost video signal at one point so popped it into Loiter first, then RTL whereupon I got signal back as the quad climbed.
I also tried to repostion in Loiter, however this didn't go so well as the quad looked like it was trying to go back to it's original postion but overshot and kept going so I switched out, not sure why?
Can one reposition while in Loiter? I.e. Sit in Loiter, then with the Tx sticks move the quad to a different position and the new position is the new loiter position?
Had a strange issue today. Was testing the Geofence in 20m simple mode and the quad bounced on the fence but then seem to go (by looking at the logs) into RTL. I had no control over it and when I switched modes to try and force it back to stabilize it fell from the sky. Only by flicking modes could I get it to loose height until I could crash it into the ground. The motors were still running and I could not disarm even though I was in stabilize on my transmitter the logs say I was still in RTL.
I cant figure it. I do have RTL as a failsafe but was only a short distance from home.
Anyone want to take a look at the logs and see what they think?
2013-02-08 11-30 12.log
Hey guys
Which are PID parameters of position hold?
I have no problem with stable, altitude mode but when I switched position hold, my copter wobbling.
Hello,
Can someone please clarify me the concepts AHRS_BARO_USE, AHRS_GPS_GAIN, AHRS_GPS_USE?
What happens if I have all 3 at 1 like
AHRS_BARO_USE,1
AHRS_GPS_GAIN,1
AHRS_GPS_USE,1
Will the computed altitude be a mix of baro and gps readings?
Right now I have
AHRS_BARO_USE,1
AHRS_GPS_GAIN,0
AHRS_GPS_USE,1
and sometimes in ALT_HOLD the quad descends too much (you can see it in the vídeo at 8:30 to 9:00).
Here is the vídeo and the logs.
Regards,
Miguel
2013-02-02 Pista Corroios AltHold & Stabilize.log
2013-02-02 Pista Corroios AltHold & Stabilize Tel.tlog
Something I've noticed using the 3DR radio's, if signal is lost by the 3DR radios (out of range or power disconnect) using APv2.68 and signal is then regained the MP reconnects and carries on as if nothing was wrong.
With ACv.2.9.1 it never reconnects requiring the connect button to be clicked
Can anyone confirm?
Regarding inertial, Biggest problem seems to be motor / prop vibration.
Solution is actually pretty easy, proper isolation and dampening of Flight control board.
I started a discussion on Vibration isolation and dampening for 2.9 - - and have managed some excellent results myself.
Check out the discussion and the replies:
http://diydrones.com/forum/topics/vibration-isolation-and-dampening...
I O-ring suspension mounted my APM 2 in my Flamewheel 330 and managed + and - 1 Accel vibrations.
Plus and minus 5 is more than adequate for solid inertial and that is what I have on my Flamewheel 450 also O-ring suspension mounted but not optimized as well as the 350.
This isn't rocket science, the biggest problem is for those people using dampening materials, they usually use way too much of it or way to stiff a material for the really light APM (or PX4) flight control board.
The shock isolation / dampening system needs to be optimized for the mass (weight) of the control board and the flying vibration frequency and amplitude of the air frame.
For us that translates to not much total movement, very progressive and just the right amount of dampening.
Check out my discussion and if you can't de-vibrate your flight control board adequately for inertial navigation youve got a lot bigger problems than that.
Inertial nav is the future because it is A LOT better, make the move and move on we are going to need what little extra code space we can squeeze out of the APM to do interesting new things not hold up old inadequate methodologies.
Inertial is the future, NAZA, WKM and Mikrokopter use the inertial for the correction... always!
Is when I walked in ArduCopter that i speak and insist on "inav correction" implementation, now that Randy has done miracles we just have to improve it... :-)
But INAV require nice setup, good balanced props and motors, nice frame, in two words "less vibrations".
In my drones I had to install APC SlowFly, with propellers that I had before there was no way to successfully operate the inertial.
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