Warning #1: an issue has been found with Tower's Pause button which can cause the vehicle to fly to an old position if the vehicle has not sent a position update to Tower in some time.
Warning #2: Copter-3.3.2 fixes a bug found in Copter-3.3.1's desired climb rate initialisation which could lead to a sudden momentary drop when switching from Stabilize or Acro to AltHold, Loiter or PosHold.
Warning #3: Copter-3.3.2 fixes an issue found in Copter-3.3.1 which could lead to hard landings in RTL or AUTO if the WPNAV_SPEED_DN was set too high (i.e. >400 or 4m/s) and/or the WPNAV_ACCEL_Z was set too low (i.e. <100 or 1m/s/s).
Warning #4: a bug was found in Copter-3.3 which could cause a sudden crash if you abort a Take-off initiated from a ground station. Video description is here. The bug is fixed in Copter-3.3.1 so we recommend upgrading.
Note #1: AC3.3-rc8 corrected a long standing bug in the HDOP reporting. HDOP values will appear about 40% lower than previously but this does not actually mean the GPS position is better than before.
Note #2: if upgrading from AC3.2.1 the vehicle's accelerometer calibration needs to be done again.
Note #3: set SERIAL2_PROTOCOL to "3" and reboot the board to enable FrSky telemetry like in previous versions.
Note #4: the wiki will be updated over the next few weeks to explain how to use the new features
Copter-3.3.1 is available through the mission planner. The full list of changes vs AC3.2.1 can be see in the ReleaseNotes and below are the most recent changes since AC3.3.
Sadly this version (and all future versions) will not run on the APM2.x boards due to CPU speed, flash and RAM restrictions.
Changes from 3.3:
1) Bug fix to prevent potential crash if Follow-Me is used after an aborted takeoff
2) compiler upgraded to 4.9.3 (runs slightly faster than 4.7.2 which was used previously)
Changes from 3.3-rc11:
1) EKF recovers from pre-arm "Compass variance" failure if compasses are consistent
Changes from 3.3-rc10:
1) PreArm "Need 3D Fix" message replaced with detailed reason from EKF
Changes from 3.3-rc9
1) EKF improvements:
a) simpler optical flow takeoff check
2) Bug Fixes/Minor enhancements:
a) fix INS3_USE parameter eeprom location
b) fix SToRM32 serial protocol driver to work with recent versions
c) increase motor pwm->thrust conversion (aka MOT_THST_EXPO) to 0.65 (was 0.50)
d) Firmware version sent to GCS in AUTOPILOT_VERSION message
3) Safety:
a) pre-arm check of compass variance if arming in Loiter, PosHold, Guided
b) always check GPS before arming in Loiter (previously could be disabled if ARMING_CHECK=0)
c) sanity check locations received from GCS for follow-me, do-set-home, do-set-ROI
d) fix optical flow failsafe (was not always triggering LAND when optical flow failed)
e) failsafe RTL vs LAND decision based on hardcoded 5m from home check (previously used WPNAV_RADIUS parameter)
Thanks for your testing!
Replies
A USB software defined radio is a good way of diagnosing interference. They can be had from ebay for $12-16. Then download some scanning software and do a scan from say 1550 to 1600mhz and see if there's anything showing up around 1575 (where gps operates). If you do get interference, disconnect one item at a time (a process of elimination).
Could you please point out a model, make of radio you referring to, or url to one on Ebay, so I can get a ideal of one your talking about.
thanks for the info.
Has it flown successfully? I ask because I make it rule to keep the vtx antenna away from the GPS/compass and pointing down. That looks like a 1.3 ghz and could be wreaking havoc on them.
Yes, definitely antenna at this position jamming both GPS and compass.
Just screw it below the body under the battery. And move the GPS/compass pole at the place of the antenna, just behind the camera. You should keep the sensors away from all antennas.
during your position incident your number of GPS sats suddenly dropped from 13 to 9....this probably caused a shift in position which is visible if you plot GPS.LAT/LONG and POS.LAT/LONG and AHRS.LAT/LONG you clearly see it, its also shown in NTUN desired vs actual position as well (for position, velocity and acceleration, they all show it very well the discrepancy)
Like you I also struggled with a couple crashes with sudden position changes too (one of them dangerous!) , it was frustrating, I eventually replaced the GPS and never had an issue ever again (using M8N now).....not saying is the same problem for you, but just something to think about
Ivan, I think that is exactly what happened, but I didn't know how to verify that theory in the log data. I did not know any GPS units but the uBlox worked with the Pixhawk. I will get an M8N and hope for the best. I think there are other unrelated problems with my Pixhawk, but some further experimentation with Andy's suggestion will prove some of that out, too. Thanks for your info!
Rick
Your log doesn't look overly strange to me. Sure you get a spike in the EKF, but it settles down again and is not massively high. What I don't get is what caused it. GPS/MAG look ok to me. The only thing that is weird is the AccelZ on the IMU's are about 1m/s/s out. There is a drop in GX at about the same time, but not sure whether that is related. If your accel offsets are badly affected by temp you might want to try calibrating at operational temp rather than room temp.
By "new" I mean it was shipped in July 2015 and has never been crashed. That should have been made after the known issues that plagued my last Pixhawk.
Hello Vesselin,
first of all thank you very much for your detailled and well explained analysis. It is a big help for me as a arducopter beginner.
You consider the ESCs (or at least the "lonely" one) to be the reason for the crash. And indeed there is a lttle hole in the heat shrink tube of the ESC that drove the "lonely motor". Severeal tests on the bench after disassembling the showed any anomality.
The ESC (AfroSlim) is rated at 20A and on full throttle (servo tester) there is a draw of 13A.
Nevertheless, the log should´ve recorded until the craft hitted the ground (Alt=0) even if there had been problems with one ESC, shouldn´t it? The Disarming ends the log at a height off 20m.
It´s a pity that there´s was no RC Out logged at this particular flight.:( The log bitmask is now set to 176 126
On another forum, there was said, that the Disarming was due to the large DesRoll-Roll and DesPitch-Pitch deviation of more than 30 degree. For me, that could be conclusive as well.
What do yout think about that?
Again, thank you for your help!
The extremes of flight, where no reaction of motors, the controller detects as crash - so there "crash" disarm, similar to the situation where copter hits a structure in air. Then everything stops, no recording.
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