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
re- 5) EKF fixes/improvements
a) prevent yaw errors during fast spins
Would this be related to the 'DCM Bad Heading" warning? It seems to occur more with fast spins in 3.2 anyway.
Richard,
Yes, in AC3.2 spinning quickly leads to a heading error which triggers the DCM check. AC3.3 uses the EKF by default (DCM as backup only) but it was suffering from the same problem. In case it's of interest, the underlying issue (according to Paul Riseborough) is that we don't correct for the gyro *scaling*. So the gyro readings are accurate when the vehicle is rotating slowly but once it's spinning quickly the gyro readings can be off by up to 5deg/sec. There's some talk of trying to learn that gyro scaling but it's a little tricky. The fix was to stop trying to learn the gyro drift (which is where the scaling errors would show up) while spinning fast and instead use the compass more.
Thanks Randy
New to the PX4Flow discussion - two questions I have,
- is the reading from optical flow is used by Pixhawk if GPS is enabled? (or can it be used as backup in case of GPS glitch)
- does PX4Flow require onboard sonar or without sonar but with Lidar mounted (pwm) would it work correctly (Wiki page video indicates a "yes" answer)
Thanks,
Hi,
I just tested rc4, specifically the brake function (assigned to an aux option). It seemed to work fine at first, including entering in and out of it though a smoother transition to modes such as stabilize might help in case one were to bump the throttle while in brake...
After holding in brake for awhile though, the quad's altitude began to fall very slowly. Here's a log. Quad has a LidarLite alt sensor and it is enabled. Hopefully I didn't miss an obvious cause.
Otherwise awesome! Thanks to all the devs!
Tom,
Ok, we've found and fixed this bug in which the vehicle slowly descends in Brake mode. This will go out with -rc6. Thanks for the report!
Hmm... I see that. Odd. It seems to happily allow the copter to slowly fall. Will have to look into this. I'm not sure if it is the same for all, or if it only affects when using Rangefinder.
Thanks for looking at this Rob.
A few more...
Lidar on 1 - there is a fairly large discrepancy between the lidar alt and the CTUN alt. Quad slowly drifts toward ground (asphalt), I stopped it at about 10 inches off the ground. This doesn't seem to effect performance in pos hold though. The LidarLite is hooked up on the PWM interface...
Lidar off - Actually drifts a couple feet up over nearly a minute.
Lidar on 2 - Less alt discrepancy this time. This log highlights that vertical station keeping just doesn't feel as solid as alt hold or pos hold. These flights were all in the evening, dead calm weather.
And while I've got your ear, I noticed that changing the mode switch (ch5) while Brake is on disables Brake mode. Is this the way it was intended? My idea for break is to use it as a panic button. Swap out a switch on my Taranis for a pushbutton, and now new pilots can hit it if they panic while flying. However, if they flail enough to hit the Ch 5 switch in their panic, down we go. Seems to defeat a major purpose of this to me.
Hi, been flying Tarot 650, 15inch props, 470kv motors, Pixhawk with AC v. 3.2.1 without a problem, PID gains from v. 3.2.1 autotune. With version 3.3 RC4 it is rather unstable, motors pulsing in Alt Hold and Loiter and the quad is not able to maintain altitude properly as before. Log is attached.
2015-05-18 22-08-29.log
Hi Arni,
I have been talking to Paul about this and you have set EKF_GPS_TYPE to 1. That means you arn't using the GPS velocity in your alt hold estimate. This isn't helping things.
Paul suggested if you have non standard parameters you should probably do a full parameter reset and start again from scratch.
There are some other parameters that have changed too now I think about it. The alt hold pid names are now different. Have you changed them from default, if so they are not back to default.
So set EKF_GPS_TYPE to 0 and check to make sure your alt hold parameters haven't changed.
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