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
14kg quad?what motors is that?
Using u10's on 12s. but I am upgrading to u11's now. U10's were a little bit underpowered.
Hi Craig, sorry for your crash.
Your idea for a servo rail voltage failsafe is a nice one. However it would not have saved you. The fact you would power also via the power port would not have saved you either. Why? Because if you get a voltage above 5,7V (short burst spikes for example which are frequent if you connect servos on the servo rail), Pixhawk will protect itself by shutting down.
So the only good way to avoid your crash was to follow what is written in the manual and plug a zener diode (trimming any spikes above 5,6v) on the servo rail.
Hope this helps,
Cheers
Perhaps a bidirectional TVS would be even better as they can sustain larger current.
So if a switching and noisy power system decide to behave badly, a bidirectional TVS will shut it down very quickly.
There are number of companies producing them but just for example littlefuse:littltfuse bidirectional TVS
Just my 0.00002 cent.... (has been limited by a TVS) :-)
Cheers
Henri
thx for the link, this looks interesting.
As far as I understand when servo rail power goes above 5.7, power from that rail to the pixhawk processor/electronics is cut by a switch or ideal diode or whatever.
But pixhawk will continue to be powered from power module port (as long as it is below 5.7v)
Is it right?
Craig was not using a power module. So Pixhawk will shutdown if it sees a voltage spike on its servo rail. That is why you need to install an external zener diode on the servo rail that cuts (trim) any voltage spikes above 5.7V.
Correct, but I could have had a 5v bec plugged into the + and - pins on the pwr module, and that would have saved my bacon. Pixhawk would only have shut down power to the rail, not shut off completely. At least that is how I understand it now. Am i right or wrong?
The order of priority taken by Pixhawk is : 1-Power port then 2-Servo rail. The servo rail power comes into account if the power port is not used. (there is also theoritically another powering option via the USB port which is not used in flight, only on the bench).
I have to check the theory on the bench that in case the power port is used, if you get a high voltage spike on the servo rail (even if power port was powered), the pixhawk will not reboot as this would happen if powered only by the servo rail....
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