Copter-3.4-rc2 available for beta testing

Copter-3.4-rc2 is now available for beta testing through the Mission Planner’s Beta Firmwares link.

A relatively complete list of changes are available in the ReleaseNotes.txt but I’ve copied them below as well.

Thanks in advance to the beta testers! When reporting issues with this release, please put them in new topics in the Copter 3.4 section or an existing topic if you find someone else has reported a similar issue.

Changes from 3.4.0-rc1
1) ADSB based avoidance of manned aircraft
2) Polygon fence (works seamlessly with circular and altitude fences)
3) Throttle related changes:
    a) motors speed feedback to pilot while landed - motors only spin up to minimum throttle as throttle stick is brought to mid (previously spun up to 25%)
    b) MOT_HOVER_LEARN allows MOT_THST_HOVER to be learned in flight
    c) THR_MIN becomes MOT_SPIN_MIN
    d) THR_MID becomes MOT_THST_HOVER
4) Precision landing:
    a) control improved by reducing lag from sensor and correcting math errors
    b) descent rate slows to allow time to correct horizontal position error
5) Guided mode:
    a) velocity controller accelerates/decelerates smoothly to target
    b) Guided_NoGPS flight mode added to allow companion computer control in non-GPS environments
    c) stop at fence if using velocity controller, reject points outside fence if using position controller
6) Throw Mode:
    a) THROW_NEXTMODE parameter allows copter to switch to Auto, Guided, RTL, Land or Brake after throw is complete  
    b) Throw mode fixes so motors reliably start
7) Attitude controller:
    a) use Quaternions instead of Euler angles
    b) ATC_ANG_LIM_TC allows controlling rate at which lean angles are limited to preserve altitude in AltHold, Loiter
8) EKF can use range finder as primary height source if EKF2_RNG_USE_HGT parameter is set to 70
9) Bug fixes
    a) AutoTune fix so that gains do not fall too low
    b) Rally points with altitudes no longer cause vehicle to climb above fence during RTL
    c) various EKF fixes including bug in initialisation of declination co-variances
    d) SingleCopter, CoaxCopter flag gains 
10) Small enhancements:
    a) Rally points outside fence are ignored
    b) AP_Button support added to allow ground station to see if user has pushed a button on the flight controller
    c) support for PLAY_TUNE and LED_CONTROL mavlink messages to cause vehicle to play tune or change colour of LED
    d) support for GPS_INPUT mavlink message to allow supplying vehicle position data from other sources
    e) NAV_DELAY mission command to delay start of mission (or individual command) until a specified absolute time
    e) TKOFF_NAV_ALT param allows take-off with no horizontal position hold until vehicle reaches specified altitude (intended mostly for helicopters)
    f) SCHED_LOOP_RATE param allows slowing main loop rate from default of 400 (intended for developers only) 
11) Safety (in addition to Fence improvements above):
    a) Motors begin spinning 2 seconds after arming (previously motors spun immediately)

Warning #1: please check the MOT_THST_HOVER parameter and ensure it’s between 0.2 and 0.8. If it’s higher than that, please reduce it back to a reasonable value (check CTUN.ThO) and set MOT_HOVER_LEARN to 0 to disable the learning of this parameter. The issue is that it’s possible (although unlikely) that during user ground testing, the hover-throttle can be learned to be too high and that when entering AltHold (or any mode in which the autopilot controls the throttle) it may climb and climb until the pilot re-takes control in Stabilize or Acro. This will be fixed in -rc3. The problem can also be resolved by increasing the ACCEL_Z_IMAX to 1000.

Warning #2: TradHeli testers should not test with -rc2. Instead please wait for -rc3. The reason is (see below) Rob experienced a premature disarm during landing so we will add extra velocity checks to the landing detector.

Warning #3: TradHeli testers should set H_COLYAW to zero for now (or at least make it very small). The scaling of this parameter is being scaled incorrectly in -rc2. This will be fixed for -rc3.


Awesome job Randy and team!

Thanks for the great continued work on copter :slight_smile:

Love the mot_hover_learn and the throw_nextmode, I’ve tested both quite a bit and they work great.
Autotune still producing dud tunes on small quad for me like others.

Good news and I will test it tomorrow…

With RC2, the copter is yawing to a given angle on guided takeoff. The yaw field is 0 currently. Is the yaw angle being used now? It doesn’t appear that the yaw field is being used in MAV_CMD_NAV_TAKEOFF.

Can’t calibrate oneshot125 with MOT_PWM_TYPE = 2, but good calibrate with MOT_PWM_TYPE = 1.
After reboot press safety for arming and have beep only 2-3 different escs. After arming this motors work and another go to calibrate mode. In rc1 I not have this problem.

Ok, I think you’ve sent me your log file in an email so I’ll have a look.

Let’s create new topics instead of replying here.

I have tried with alt-hold, loiter and auto (take-off, waypoints and RTL) Looks good to me

A post was split to a new topic: Autotune never ends (rc1 and rc2)


Last night while testing RC2 on my heli, I did an RTL. It flew home perfectly, hovered over home, then started descending. Then disarmed and crashed from about 30m up. We analysed the logs and understand the problem, it appears to be an issue that would only affect helicopters.

I’m not totally convinced that something else hasn’t changed. Because, the issue with the helicopter landing detector, hasn’t changed from AC3.3. This helicopter has over 200 flights on it with AC3.3 without this ever occurring before. Most of these flights were manual, but there were some auto-landings. However, on it’s first autolanding with AC3.4, it failed. That seems suspicious.

A post was split to a new topic: Can’t fly above RNGFND_MAX - rc2

Extremely pleased with 3.4-RC-2. Fly’s great right out of the box with default PIDs on a Lumenier QAV250.

Video -

Thanks for the excellent work guys.


Lumenier QAV250 AUW 615 grams, 8.4 amps at hover.
SunnySky X2204S 2300KV motors with Graupner 6x3 “C” props.
Velotech Magic 12A ESC SimonK
HK Turnigy Graphene 1300 Mah 3s battery.

I flew my 450 size heli using the firmware today. It worked fine in stable/poshold/loiter/auto modes. Just for fun, I tried to set AHRS_EKF_TYPE to 1 to use the old EKF. However it keep changing is back to 2. Other than that, it flew flaw less.

Tested 3.4RC2 on Y6 with PixLite. Autotune and some guided tests. AT resulted in an excellent working set of Parameters .
Still have to use Alt ASL for Guided ALT in Tower. Is there a way to use REL ALT?
Perhaps this is the wrong place for suggestions, but I´m a big fan of the Y6 and for some reason AC Y6B uses only CCW-rotating motors for this Frame. Is there a simple way to change this to all CW? A lot of motors are only sold as CW and using them as CCW lets you lose the self-tightening capability of the Prop nut.

Log is here.

4 posts were split to a new topic: Rc2: Inconsistent values between MOT_THST_HOVER and PWM output

Regarding Tower, I heard from Fredia that the new beta has a fix for this. I’m slightly unsure if he’s pushed that out or not so I’ll check.

Thanks very much for the testing and reports.

I’m going to close this topic because we’ve got the new -rc3 release now.

@rmackay9 I think you should create a newpost for each release and pin-it, and unpin the old. Otherwise it hard to see the release notes for previous versions. Thx