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
Silly question, but how do I turn raw data logging on/off so that I can see Accel Z values?
Thank you.
Tuning Question
During straight between waypoints my quad twitches a but in pitch and roll (more noticeable in pitch). What do I need to adjust? Loiter is excellent.
Also it seams to slow down and takes a while to hit a waypoint. That is worse with higher WP Speed. Changing WP radius has no effect on this problem. Seams to be worse going into the wind.
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Any news on 2.9.2?
I'm sure this has been asked before but I can't seem to find the answer.
Is there a way to make mission planner auto reconnect once the telemetry link is lost?
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Throttle failsafe behavior.
I was pushing out the range yesterday on a 12 waypoint mission when, after WP 6 I heard “heading to waypoint 1” and the copter stopped and started to descend. Waypoint 1 was ‘takeoff to 20mts’. (it was at 35mts). I then hit RTL.
Checking the logs, it was a low spike in CH3 – throttle failsafe. Must have been so short that it went straight back to auto. I didn’t see any RTL mode.
I do have throttle failsafe set up and the second mission it also failed in the same place except with RTL.
Is that what it meant to happen with a brief failsafe – mission reset? Would be better to pick up the mission from where it stopped.
Didn’t there used to be a telemetry failsafe option. Cant find that now.
Very disappointed in the range of this 2.4 stuff. That was obliviously the reason for the crash of my big 3m glider last year. Should have had an APM on it.
Hello,
I'm trying to connect my APM2.5 (Arducopter 2.9.1) with Mission Planner 1.2.33, MP start reading my parameter and suddenly stop after reading 3/4 parameters. If I try a connection with "Terminal" it's working fine, if I upload code with Arduino to APM2.5, it's working fine. Blue led C on APM2.5 stay fix.
I don't know what is the problem, any ideas ?
Thanks,
Have been trying to get my head around the new release and the use of the X & Y accelerometers.
I wouldn’t mind a brief dummies guide to wet the appetite.
Surely the motors can only act directly in the Z plane? Even a tilt, in the short term, would produce no side forces until there was some speed and drag effects.
So I suppose a level copter in the hover ‘feels’ a side gust and works out how far its got blown. Id imagine the brief tilt to re-position would see very little X or Y accelerations.
Im just imagining a sprit level on the copter and expect it would only be non-central during a gust or motion induced wind.
I'm guessing this has been asked, but this thread is huge to wade through: regarding altitude hold on this new release:
It works AMAZING but: When I move the throttle out of the deadband (wish to command a gentle climb) the thing ROCKETS up. Moving back to the middle it stops on a dime, impressive.
What should I adjust to make it so that when I move the throttle just out of the %20 dead band that it climbs or descends much more gently?
Thanks for the help!
Ted
More Tuning questions.
Previously I have followed Dave C’s tuning guide on a jig, using acro (the old one) and setting stab terms to zero. As the guide says, a high rate D will give a ‘buzz’ type vibration. (does this still happen with 2.9.x?).
I am now pushing up the rates while flying in stab mode. Rate D is currently .016 – quite high, no sign of the buzz vibration, just a ‘flying in treacle’ as the name ‘dampening’ would suggest. Rate P now up to .26 – also very high. Still flying very nice.
Am I likely to see this classic D buzz while flying in stab mode?
Is it possible that I may get no warning before the tuning goes unstable?
Is anything to be gained from pushing up the tuning further (apart from satisfying my curiosity)?
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