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
Hi, Randy!
I have a question concerning navigation.pde and void calc_velocity_and_position() https://github.com/diydrones/ardupilot/blob/ArduCopter-2.9/ArduCopt.... Somehow i can understand the calculation of the W-O speed since it takes a factor into account, correcting 10^7 degreefloat, converting to rad and doing a cosinus on it. But the N-S speed is just a substraction of latitudes (they come as *10^7) in degrees multiplied by the timefactor - and that gives cm/s ? I know that both parts are approximitations without earthradius etc... anyway but the N-S speed seems really strange to me. I expected instead of this:
lat_speed = (float)(g_gps->latitude - last_gps_latitude) * tmp;
something like this:
lat_speed = (float)(g_gps->latitude - last_gps_latitude) /10000000.0f * RADX * tmp; //#define RADX M_PI / 180.0f
perhaps double instead of float on non-arduino systems.
What is your opinion on that?
Cheers
Kraut Rob
RAW Data?
If I want to look at accelerometer vibration data do I set SR0_RAW_SENS to 1 or SR3_RAW_SENS to 1? What’s the difference?
.
Is it possible that some of the GPS drops are actually issues with the GPS data transfer to the mission planner? I can't determine if it was linked with 2.9.1 or with the recent MP, but I have seen a few cases where some of the data steps in the MP. Check the attached tlog. The quad flew the route very nicely (indicating it had good GPS data), the GPS always shows as 3D Fix (would it continue to show this if there was no GPS packet coming in?), but the position updates come through very infrequently. The attitude data is fine.
I don't have a log of it, but I had an issue in my workshop last week where the attitude was steppy. I turned on an ardustation-like ground station which sent commands to enable the various packets then everything became smooth.
Andrew
2013-02-10 14-03-59.tlog
Wow. Just tried new 2.9 in altitude hold and was pretty damn good. Just covered the baro sensor with those woman cotton makeup remover (looks like cotton discs) and used 3M Micropore hypoallergenic paper tape to keep in place. Nice one developer team.
Loiter Tuning Question.
I have a medium-large quad that’s fairly powerful. With defaults it flies well in Stable mode. In Loiter if I get a gust of wind it will rock hard and takes a whist to dampen out. Do I have THR_RATE_P too high or do I need to adjust some of the Loiter parameters. I will be going out later today and need some advice on what to tune.
APM 2.5 with uBlox GPS.
Copter now flying really nice is all modes but would like to soften its auto flying a bit. I cant fault its tracking. The blue line is smack over the yellow one most of the time but its jiggyness is more than my camera gimble can cope with. Also at waypoints it has a minor fit before setting off for the next one. (even if its straight ahead)
By default NAV WP ‘D’ is zero. Am considering playing around with that. Has anyone much experience with this?
Is that another thing that will be completely different in the next issue? If so perhaps I should just wait. Do we have a rough ETA for 2.9.2.?
Sorry if these have been answered before, Ive just got back from 3 week biz trip and now see the hundreds of post!.
Does the level work still when holding the yaw hard to the left for 20sec?
Why has the option to revers throttle and pitch check been removed from the radio calibration area in MP? This is annoying when using the same radio for various aircraft when its much easier to set the firmware to suit.
Is it possible the developers could add a "save" button in Arducopet Config page so its quick to save each time we make an adjustment to the PIDs? Also would be good of ArduCopter Config was its own item rather than a sub menu of Standard Params. The clicking back and forth drives me nuts on my slow field lapy
Suggestion for Auto mission planner.
'Rotate L/R at given rate.
Just do a 360. Good for filming.
If loiter turns worked perhaps could use that with zero radius but I dont think rate is adjustable and it dosent work anyway - for me.
Unless its already there by another name in the camera bits?
Just to be interesting. I have another issue. Had successful missions the previous day but on Saturday things went wrong,
Was flying the mission and the quad started climbing in altitude and then started to come down. It kept coming down into the ground. Looking at the logs I see it way overshot the target alt but then Im not sure what happened.
Can I trouble someone to take a look and comment. Not sure if its a fault or something else.
2013-02-09 08-46-36.rlog
Graham pointed out that his quad gains elevation after the second time he uses loiter. I tried to recreate it today, but it was so windy I had my hands full and could not do a good job with it. But it did climb until it tried to switch from sonar to baro, then it gets jumpy and scarey and I switched out of loiter.
So I backed up to yesterdays logs and here is what I found. Note that I generally don't go in and out of loiter so much, but I was trying to fly under and around trees in the yard, and I kept moving over grass, then cement, then over a dirt patch etc. It always got worse. Here's some pix and logs.
Looking good, altitude stays pretty tight in loiter #1.
Not bad, but maybe a little trend in Loiter #2.
Loiter #3 heads up, Loiter #4 heads up too.
Loiter #5 and #6 Going Up! I counter act with the throttle, but it was steady going into loiter.
Loiter 7, 8 ,9, up up up.
Loiter 10. If anything it's even more aggressive.
I know this isn't a lot of climbing, I couldn't afford it under the trees though. Maybe if I just sent it up high enough it would have settled.
2013-02-09 16-45 16.log
2013-02-09 16-06-01.tlog
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