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
Kurt,
Quite often you can reduce the Z axis vibration level by reducing the amount of bell play in your motor housing. As your props load and unload in flight the changing load on your motor causes the housing to jump up and down within the "play" on the shaft. You can reduce this by using a special clamp to compress the housing on the shaft, reducing the amount of excess bell play. The more bell play the greater the vibration as the housing jumps back and forth between the limits. The trick is eliminating the excess without inducing friction or drag on the motor.
Myself and others have seen dramatic reductions in Z axis vibration by eliminating this excess bell play.
Regards,
Nathaniel ~KD2DEY
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Kurt,
I can't take credit for the idea, someone here led me to the same information, paying it forward as they say! If you can't feel any additional end play, then it probably isn't a major contributor. Still worth looking at, but not likely to help a lot unless you can feel some end play.
As far as what the clamp looks like, it's fairly simple and from what I've seen, usually home made. The basic construction is usually a section of square steel tubing large enough to encompass the motor. A hole is drilled and tapped in the top center and a bolt is threaded in that location such that when a motor is inserted the bolt can press on the shaft. Opposite the bolt a clearance hole is drilled for the end of the shaft on the other side. There is usually a grub screw on the bell that secures the bell to the shaft. Once this is loosened you can compress the shaft and the bell housing together.
I'm not sure where the original thread is but I'll look around and see if I can find it. I think it was Leonard who originally posted the fix in this thread.
Yes, Arms flexing could definitely cause Z axis vibrations.
Regards,
Nathaniel ~KD2DEY
That is the acceleration in the vertical axis.
You might see spikes when you bump the ground?
Hello all,
A crash apear on my octocopter but I don't understand why...
I have see the log but I'm not an expert of log review and I can't define the source of the crash.
(The log notify a first crash but it's just an error of me on the take off the real crash is the second one.)
Version is AC3.3rc12.
Thank you in advance.
I hope my experience will also help other people.
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Hi Ruchat,
You have a massive motor output mismatch. It looks like motor 4 is struggling.
Sorry to hear about your crash!!
Hello,
Thank you for your analyis I will check my motor 4.
Have a nice day.
Sorry my ignorance, How do you detect that motor 4 is the problem there?
Hi Cala,
I am plotting RC out there and in a steady hover the lines should be pretty much on top of each other.
I can see Ch 4 is a problem because it is much higher than any of the others. You can also get similar problems if your arms are twisted.
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