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
I use RTL and land once in a while and even land from a mission. They work every time for me. Landing detection has gotten way better than it use to be.
The thing is that I land often in Stabilize mode because of GPS Doppler effect from trees and building near my landing area. It is far safer to land in this mode than risk GPS drift causing the craft to veer off and hit something.
If your in an open area it should be fine to land in Loiter/Position hold or use RTL. Motors always spin down and stop. Too often people fly in front of there house and get unexpected results.
To get a good HDOP the satellites need to be very far apart from each other to get good contrasting angles which improves HDOP. This means that the satellite on the horizon that is blocked as you land is going to change the HDOP and your position.
GPS is certainly important to consider for trying to land in Loiter/Pos Hold, but I believe the issue is quite evident for Alt Hold as well.
yes, I agree. I've learnt to land in landing mode/loiter, then the second it's landed to switch to stabilize and drop the throttle, but as you say that's not a great solution.
the devs have done quite a bit of work on the landing detector but then I think caused a few false positives where the craft then thinks it's landed (but hasn't) and drops the throttle so it then drops out of the sky. for me, it's better to have a tipover and lose a prop or two than have it drop out of the sky - i make sure to land it well away from me or anyone else for this reason, half expecting a tipover.
as I understand it, currently it 'feels' for the ground but doesn't really have any idea where it is, kind of like a blind man feeling for an obstacle. and if it's too optimistic, it will sometimes 'feel' something that isn't actually there, if it's too pessimistic it won't 'feel' what is actually there. as randy said in an earlier post, the real solution here is to use a range finder to actually know where the ground is - if we know from the rangefinder we're on on very near the ground then it's much easier to drop the power reliably, I guess.
hopefully this is something that can worked on for 3.4.
I'm pretty sure that is impossible now as they added another check that will not allow it to decided it's landed if the throttle is above 1/3 or something along those lines. So if your flying it's obviously above that.
A kill switch is an ok idea, but requires another pilot input just like flipping to stabilized mode. The goal should be to fix this problem through a way that protects novice pilots from having their multi tip over.
I like having stabilization functioning even after I touch down. During windy landing or when landing on uneven terrain I want to see that the multi is stable on the ground before I bring the throttle to minimum.
Could the GPS radius for position hold be loosened up when throttle is at minimum?
Another approach might be limit the maximum tilt angle to 10* when throttle is at minimum so that the multi would not be able to lean far enough to tip over in the first place.
It should also be noted that a number of flight controllers actually "turn off" the integral portion of the PID during take off to prevent flipping in situations where the operator increases the throttle slowly.
This "flip on landing due to a small lateral move" problem really looks a lot like an unbounded integral wind-up issue. Preventing the error from accumulating to an unreasonable degree should do much to control this.
Limiting a max tilt angle is also something that should be prioritized over position corrections in a landing type of flight mode mode. I suspect that without first better limiting integral wind-up, limiting max tilt angle won't actually be effective.
It would seem that the ideal behavior would be as follows: In a situation where a copter meets resistance while moving laterally, it should tilt in a controlled manner to a maximum angle and then hold that angle indefinitely.
This may fall under the category of "easier said than done", but it seems like a reasonable goal. Very likely the changes needed to effect this behavior would result in undesired effects in some flight modes, as such it might make sense for the changes to only be effective in landing types of flight modes modes.
I have been flying with rc10 since it came out and everything was fine till today.
I was on my second battery of the night and after 5-6 minutes for some reason my Y6b suddenly rolled/yawed in place and then would straighten out again. This was in stab mode with simple mode on. This happened several time and then the copter seamed to loose power and started slowly decending. I was still able to apply roll and pitch but it ended up coming all the way down and flipping over when it hit the ground.
After the crash I noticed that the GPS mast was a little bit loose and could easily twist 5-10 degrees. Not sure if this was caused by the crash or went loose during the flight.
attached is the log from that flight.
Any thoughts/insights would be greatly appreciated.
hmn log file didn't seam to attach so here it is via google drive
https://drive.google.com/file/d/0B9lPaNf0CEySMGFLRy15WW00bzQ/view?u...
Yssaril,
Thanks for testing.
Looks like motor #4 (bottom back) is failing. It shows the classic signs which is sudden separation of the desired-pitch vs actual-pitch (it suddenly pitches back which is consistent with a rear motor failure) and the output sent to the back motor goes to full (i.e. it's trying to get more power out of the motor but it's not).
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