AC3.3 TradHeli Release Discussion

WARNING to TradHeli users:

Do not attempt to fly AC3.3 until you hear otherwise from me.  I have not even bench tested it yet, let alone test flown it.  There are quite a lot of changes that have gone in that could be crash-o-matic for helicopters.

AC3.3 release for Tradheli is likely to be delayed.

This post will serve as the official release progress thread for TradHeli.

Warning: DO NOT FLY RC6!  It has a critical bug that will likely end in a crash.

Warning for RC5:

RATE_YAW_FILT_HZ param will change defaults from 5Hz to 20Hz to be more suitable for helicopters.  If you have never changed this parameter from 5 before, then it will automatically update the value to 20 without warning.  This much faster filter will probably require reduction in your P and D terms, and the yaw may oscillate badly.  Be prepared to retune these.  As a safety measure, probably cut them in half for your first take-off.

Warning #2 for RC5:

I accidentally broke the Landing Detector.  It will probably never trigger.  You should land in Stabilize mode, or be prepared to shut down the motor as soon as it touches the ground in Alt_Hold, Loiter, Auto, etc.

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    • Yes, not really any upgrades but some under the hood changes that effect parameters.
      From the release notes of rc4:
      7) TradHeli:
      a) parameters moved to stop possibility of corruption if board is switched between tradheli and multicopter firmware. Heli users may need to re-setup some heli-specific params.
      b) H_COLYAW param can be float
      Read back in this discussion to see examples of parameter changes.
  • Hi Rob,

    I don't know if I am the only one with this problem, but could you please make Ch7+Ch8 accessible with RC7(8)_Function=1 when these channels are not needed by the program.

    Thank You

    • Sorry, not understanding this either.  You want to be able to use the Ch 7 & 8 outputs if not using them for an ESC?  How are you going to control the ESC?

      I am actually wanting to make these official Aux Functions.  It would allow you to switch the ESC on/off using any aux channel input (7-12) and then likewise, use any aux channel for the ESC driver.

      • Hi Rob,

        this is based on a lot of assumptions and MY problems, please correct me where I am wrong:

        With 3.2.1 I cannot get any any servo movement setting RC7_Function=1, is this my own problem or expected behaviour ? I think it is written somewhere that Ch7 is reserved for ext. Gyro / DDVP, therefore I was asking to add something like 'if you don't need Ch7, you can use it for servo'. Ofcourse I can use the RX output as well, but it would be less wiring hassle in my case.

        When I use the Pixhawk to feed the V-Stabi FBL (my brushless servos work with V-Stabi, but are not happy with Pixhawk see 'D-problem' below) I use the ESC commands directly from the RX (don't know why I should send it through the Pixhawk, please explain if you have another opinion). Same as above, it would be nice for me to have servo output at Ch8 when not needed for ESC.

        AUX Functions sounds fine for me as long as there is enough space for gimbal etc.

        My 'D' problem: One of many PID tuning recipes is to set I=D=0, tune P to oscillation, set P= 60% of oscillation P and I = 50% of oscillation time and D = 12% of oscillation time. In my case this works for P and I, but is totally wrong for D. In my case the D has to be 2 to 3 powers of 10 smaller. I know you favor D=0, but heli seems to benefit from these small amounts of D. Is there a scaling error somewhere? The standard servos are o.k. with small amounts of D, but the brushless servos are not. When I tune the brushless servos in flight I must divide the D by at least ten to get smooth servo movements.

    • I think manual mode is very important,and disarm is dangrous .

      • Sorry, I'm not following?

  • I just flew my Trex 550 with 3.3r3.  I was able to takeoff and land in both stabilize and Loiter.

    Stabilize was fine.  

    Loiter required increase in Pitch and Roll Ps and FFs.  It is still has moments of loiter fore aft oscillation but I'm sure it just needs more retuning.

    Cyclic works while disarmed. Collective doesn't.  Is this by design or should I voice it?  I like to see both working before arming.  

    I think I may have too much vibration, because I see some erroneous climb after landing.  It worked with 3.2.1 but I didn't have EKF enabled.  It'll take some work getting the heli balanced again and tuned for the EKF.

    • Ray, I checked this yesterday, collective does work while disarmed in Stabilize and Acro, as it should.  It does not work if you are in Alt_Hold, Loiter, etc.  That's always how it has been.

      • Sorry Ray, this must be something that came in between rc1 and rc3.  I just updated to rc4, and have this behaviour.  I'll fix it.  Thanks for pointing it out.

    • Collective not working while disarmed is NOT intentional, thanks for noting it, I will check it out and fix it.  That will probably be a critical fix before AC3.3 can go stable.

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