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
This platform's a s***ton of work, but oh my lord is it worth it :)
RTL sorted out, RX failsafes confirmed working. RTL initially set to 1m/s because I terrified I might lose it. ALT hold and Loiter all checked out.
No more tuning - time to FLY
I had a weird event towards the end where my home position changed. I have to check my magnetometer offsets because my flight controller is literally an inch away from a 4-1 ESC...but otherwise - everything worked 100%
On evening, Loiter test low altitude.
2013-02-25 23-03 4.log
Hi all. In my last real flight, I lost power for some unknown reason from about 30-50 feet up when i switched modes during a flight. I went back to stabilize mode on the way down but it didn't seem to respond. It hit the roof of my house flat on the belly of the quad and then it landed in the lawn. Two snapped arms from the dji frame that i'm using and broke the props (typical) but otherwise no physical damage to anything else... but it was a hard smack to be sure.
test flight_more_logs.zip
Crash.zip
Altitude Drift.
This morning I was out flying and found that my quad was flying more than 5m lower after flying a 7 minute mission. I looked at the GPS and HUD altitude and found that the HUD was off and the GPS was correct. I checked and the AHRS_GPS_GAIL is 1 but the altitude did not get corrected.
Is this function working for multi-rotors? If yes, how do I get the GPS to correct the altitude faster?
.
Hi Leonard,
I have rebuilt my quad using a borrowed APM 2.0 from my friend until the other unit arrives.
Using Scorpion 2215 1070 kv and Plush 25 amp ESC. A new isolation neoprene foam motor holds the APM,
Test flights have been very encouraging with no problems encountered.
I have attached a log with RAW for your opinion on the Z Accel damping results.
Regards David
2013-02-22 19-36 16.log
Personal milestone for me.
* I didn't crash
* everything worked (mostly)
* My love/hate relationship with this asymmetrical is approaching love again. I finally have this damn quadcopter approaching a sane tune, with some help from Leonard.
* Gabor posted a new firmware for MinimOSD-extra - so I grabbed all my FPV gear and shot up for a quick flight. While I was doing that - I also tested out Alt Hold and Loiter. I plugged in a few sensible parameters and came very close to a good tune on my first try. I have to ease THR MID but other than - I like what I see - especially Loiter.
* I was too chicken to try RTL, but what I did do as a precaution was set WP SPEED to 100 - I didn't want this taking off. I flipped my channel 7 switch but it didn't work (configuration problem) but I was ok with that - I'll try again later.
Attaching my tlog from this flight - I'm still learning how to analyze these...these aren't the raw logs - I can only do basic telem.
And as always - big thank you to the devs for all your hard work!
2013-02-22 16-45-47.tlog
How do I perform the new accelerometer calibration with my Hex? The Quad stands nicely on it's sides since it has a square shape, but my Hex is more like a wheel. Can I hold it up by hand or should I get a bunch of pillows?
Randy replied to their discussion "ArduCopter 2.9 / 2.9.1 released" on DIY Drones
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Quentin,
���� Ok good news.� Loiter is a bit fidgety.� That will go away with the inav loiter & waypoint changes coming in 2.9.2.� Until then the best you can do is reduce the Loiter Rate P.
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That's sorted it thanks Randy.
I am using the channel 7 option to trigger a camera, is there a way to turn off and on the sonar using any other channel, if so how do I do that? At present I am just turning it off via deselecting it in the MP config section when I know I will be operating over rough terrain and don't want it bobbing up and down. Works a treat over flat ground, but can't handle lots of shrubs or sloping ground.
Just wnated to reprt that I finally after weeks, had a sunny dayso I ran out at lunch and flew a bit with 2.9.1, Flew a mission, did RTL several times, used Alt-Hold and Loiter (in a bit of a wind) and all worked great. Discovered after looking at the video, that one of my attachments for my camera was flopping loose and the extra bouncing vibrations had no impact on teh light (though the video is awful).
Here is the mission track:
All in all - pretty happy.
Some days you feel like the Wright Brothers.
And some days you're Icarus.
1) It was a mechanical failure. The firmware did an amazing job trying to stabilize her, but in the end the vibes were just too much to overcome.
2) Prior to this flight, I was running through the new inertial improvements (unrecorded) and - yeah - they're the bees knees.
3) I got bold - and decided to slap the FPV gear on that text book "just one more flight" flight, and you can see where that went at 3:45
The problem turned out to be a vibe that loosened the right propeller just enough to cause a fatal resonance under torque. I realized I wasn't going to land this, so I threw the dice and chopped the throttle
Damage assessment for the crash:
2 zip ties holding the feet to the frame. By some divine act - despite the fact that it did 2 flips from 20m up...it landed completely flat and upright in a nice soft pile of snow. 4 hours drying off in a nice toasty room and she powered up like a champ.
So just as a precaution - I'm swapping out some components, but man - talk about dodging a bullet!
Not even going to bother posting the telemetry logs because you can probably tell what the accel z values are just by watching the first few minutes. This was a new build and I've been diligently going through the proving runs to ensure she's flyable...this mechanical failure just caught me off guard.
Back to (re) building!
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