ArduCopter 2.9 / 2.9.1 released
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 to This Discussion
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Permalink Reply by Bill Patterson on -
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Permalink Reply by Dave Wilkeson on -
Again, I'm talking about the installed defaults, not what people can change it to for their use case. I would say too far for an airplane or copter is beyond the range required for positive piloted RC control. For battery, the software is doing a bunch of calculations based on the battery capacity you enter. I would think that 3S/4S is important for that calculation as well, but I don't see that there. My problem is you have to turn all that on. I think it should be defaulted on and you should be forced to set up your battery during initial install. You could even ask some questions about initial flying conditions to set up the battery low default. Altitude should be calculated from where launch took place (AGL) and it should not exceed normal "safe" altitude (100'?). The mission load date can be stored onboard (the .logs are date stamped so I think that variable is in there - I imagine that's coming from GPS?) so MP could calculate the mission age. If nothing else MP could compare the mission in its plan to the mission in the APM.
Again, I'm not suggesting that the software limit what you can do. I'm saying that it seems to me that the defaults out of the box are configured for an intermediate level pilot - someone who's flown and configured the APM before. An expert would tweak them and a beginner is highly recommended to tweak them. My opinion is the defaults should be built for the lowest common denominator (AKA safest flight mode) which would be beginner settings and then tweaked up. Or, if you don't like that idea, incorporate a couple of profiles. When you install a new version, ask "Use beginner settings, intermediate settings, advanced settings, keep existing settings". You could even display a settings comparison screen to show the recommended changes. There's a couple of crashes documented because their settings were from a previous version, but an explanation of how to clear all that out has to be dug out of this giant thread. I upgraded from 2.8.1 and haven't cleared my old settings (which I hadn't tweaked much) - should I have? I am assuming not based on what I've read.
I just think we need to dummy some of this up just a bit to make sure this platform is as safe as possible and that errors (pilot, settings, or bug based) that yield catastrophic failures are avoided as much as can be done if you fly defaults.
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Permalink Reply by emile 'butch' alline on -
+1 Amen to that !
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Permalink Reply by Jim Kahl on
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I'm confused by the 'Home' location too. I'm running telemetry and have the Quick tab in the Mission Planner set up to display Distance to Home and Altitude in addition to other parameters. When I set Home in the planner the Distance to Home always goes to zero and then drifts as the GPS does. When I arm either with the MP or the radio, the Distance to Home does NOT change, but the Altitude always goes to zero. I've always been afraid to try RTL because of this issue. I had always thought that Home and the arm or Launch point were the same thing -- but apparently they're not. If not, does anyone know where you can see what the lat/lon of the Arm location is stored as?
Also, if Home is not the RTL location, then what is it for? I'm confused!
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Permalink Reply by William Stoner on
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The GPS is used to determine home. It can't use itself to identify if it has an error that leads to home being 3 miles away. It thinks its still exactly where it says it is!
I think the best you can do with GPS is to ensure you have a 3d lock, if you have telemetry active you can refer to the HDOP numbers...or just look at the map, it should show your location.
None of that works if you lose GPS, or it just shows your location wrong...
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Permalink Reply by John Maffetone on -
Can someone confirm that the home location is set where you ARM? I asked a couple of times when and where the Home location is set and was told that it is set when and where the APM is armed. For safety reasons there shouldn't be any confusion about this operational point. Thank you
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Permalink Reply by Bill Patterson on
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Plug it in.
Get gps lock.
Arm it.
That's home.
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Permalink Reply by Jim Kahl on
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If that's the case, then why doesn't Dist. to Home in the Quick Tab of the MP go to zero when you Arm just as is does when you click on the 'Home' button in the MP? (see my post just above on this page)
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Permalink Reply by Jim Kahl on
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As I think about this -- I'm guessing that the Dist From Home in the Quick tab is probably referenced to the HOME value stored in the MP. This value is likely not being updated in the MP as it probably should be, when the APM is armed, but it's always updated when the Home button is pressed in the MP.
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Permalink Reply by Jeff Cook on -
FYI, I had 9-14 Sats locked during the entire adventure and I launched with "3D Fix" and "100%" telemetry signal strength displayed in the mission planner
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Permalink Reply by Joe Gordon on
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I have had incidents where I power the copter up, monitor position on the MP screen and see my shown location after it indicates GPS lock be hundreds of yards away. Home was set in these instances incorrectly. GPS position did come back to close to my actual location with time. Conditions may have been marginal with buildings and adjacent thunderstorms affecting GPS positioning but nonetheless the they did and can occur. If I start up next to a steel building nearby is sometimes can show location of by 10s of yards until I move sufficiently away from the building so a large part of the sky is not obscured from the copters perspective. This is pretty repeatable. So GPS lock alone is not a indication of a acceptable correct location. Triangulation can be more accurate with a wide angel of divergence in satellite location. I have not had any issues when the copter has full view of the sky in clear conditions.
Based on these experiences I always check with telemetry to ensure the position shown by the MP is correct before doing any autonomous flight. I also make sure I am aware of any potential objects be which could limit full sky visibility to the GPS unit.
If I had a failsafe when flying with the conditions above I would have seen my copter fly away. Not sure if this is applicable to your incident but with autonomous flight it is critical to try and ensure all systems are operational and correct before proceeding. For myself this has meant not trusting the GPS lock indication alonand added a check to make sure actual and copter perceived location are correct.
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