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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        • 3702790566?profile=originalAC3.3rc6 is out !

  • Howdy Rob,
    Still making slow progress on my TRex500 / APM / FW3.1.5 - but I did waste a big slice of time with that direct drive experiment!
    Another factor is where I fly - my back yard - which is immense - but my takeoff/landing area is small and has 10-15m tall trees all around. And if I stray much beyond the trees at altitude and crash it may well be in a canyon or another location where retrieving the heli might be tricky if not impossible. It was quite exciting to learn flying in such an area, luckily no lost models but plenty of blades and gears destroyed;>)

    Before moving on to 3.2.1 and eventually a Pix, a question or two if you please. I'd like to get the present configuration and performance finalized as much as possible before entering yet another (for me) new realm.

    I'm just about to test a mission for the first time, and am configuring a couple of switches on the Taranis. I've got a 6-pushbutton board for main flight modes, Txing over ch5. One of the buttons is auto, another RTL for example. I have in addition a 3-pos switch that gives me Alt Hold or Loiter override, also on ch5. So I can be in any flight mode selected by the buttons but quickly override that mode by the 3-way switch to get AH or Loiter.

    Now, if I'm running a mission and I decide to interrupt it using the ch5 switch into Loiter, when I then throw the ch7 switch back, will the mission then continue from where it left off?

    And what if I interrupt the mission and go to Alt Hold, move around a little, and then switch back to the mission? In that case I would no longer be at the same position where I abandoned the mission.

    I've got another "emergency override" of ch5, a switch that would do RTL, might be handy if encountering some unforseen problem with the mission out there over the canyon.

    • With regard to starting auto missions where you left off. 3.2 beta was the first FW that had the following feature:

      a) mission will be resumed from last active command when pilot switches out and then back into Auto mode (prev behaviour can be restored by setting MIS_RESTART param to 1)

      As I read the release notes, It seems that 3.1.5 did not get this but there is a little doubt, though.  The release notes seem a little jumbled from 3.1.4 to 3.2.  Check to see if you have the MIS_RESTART param.  Setting it 0 will have the effect of starting where you left off.

      When testing Auto I have only 4 modes selectable: Stabilize, Loiter, Auto and RTL.  When in auto, I'm ready with the throttle stick well above middle so when I switch into Stabilize or Loiter, I climb.  

      95% of the time I need to bailout of a problem, I switch into Stab.  The heli climbs and slows down smoothly.  Loiter will stop the heli abruptly if you made a mistake in the mission plan but it may not save a GPS glitch.  I've saved my heli many times with the stabilize and climb technique (twice from GPS glitches). 

      RTL can be scary as the copter obediently stops what it's doing and races home, overshooting a few meters. 

      Maybe for your first time, you can try a small mission somewhere else.  Trees are very dangerous when learning the ropes on Auto missions.  Restarting missions and RTL can cut corners.  The heli often loses altitude on long fast runs.  Keep WPNAV_SPEED slow at first.  

      Although I much prefer the new firmware, 3.1.5 should work well.  I was getting very high performance from 3.1.4.   


      • very helpful Ray, thanks!
        I had sort of planned to switch out of Auto into Altitude Hold for a start, then I should have a moment to decide what to do next, maybe stabilize, loiter or rtl depending on circumstances. Yes, I'm planning a VERY short quite-high-above-the-trees first mission. And I'll avoid trying any resume of mission until I start with 3.2. As far as I can see (not very far with all those trees;>) I'd only want to resume a mission if I were out of LOS somewhere. As for trees, see the attached - the little patch in the middle is my landing area. I tried many times to clear away some of the trees, but even CF blades have their limitations...


        • That sounds good.
          That is tough terrain. Maybe you should find an empty soccer (futbol?) field so you don't have to fly so high. High altitude can make it difficult to see and the wind may be stronger up high.
          Once you get comfortable with auto, that will be really great scenery.
          Good luck!
          • Nearest field with some clearance is about 40 minutes drive, and even that is no football field. Very mountainous here. So some spectacular video is definitely on the menu, but not quite yet. Some further tuning first:

            I was trying to completely eliminate some tail wag and upped YAW parameters quite a bit. I noticed on another discussion that multi guys have also found YAW PIDs in need of augmentation to eliminate yaw oscillation.

            I first put RATE_D on CH6 slider and found I could go to the limit, 0.20 with no apparent instability. I then did the same with _P and maxed that one too at 0.25 - tail wag is pretty much fixed, but I wonder that it should need maxed out PIDs, maybe the limits (as specified in "Complete Parameters" list) are more appropriate for multis? Remember, I've got an overweight TREX500 with tail motor and a gimbal and lots of battery forward to balance all. So rotational inertia for YAW and PITCH are waaay above what is ever seen on a multi. ROLL is relatively nimble of course.

            If I raise the PIDs above those limits does that have any effect? Settings now are:

            I'm just wondering if I should seek instability points as recommended in the wikis or such as when, (from the discussion mentioned above)
            "Reply by leonardthall on August 28, 2014
            Personally I would start by tuning in the same way as roll and pitch. D up till you get oscillation then half it. Repeat for P then set I =0.1 P (roll and pitch use a ratio of 1 )"

            I'm still at FW 3.1.5 - noticing 3.3 is in the testing I think I'll await that one in top form rather than go to 3.2

  • Hi Rob, I have a T-REX 500 w/pixhawk, I want to start working on again, what stable version of AC would you recommend?



    • I wouldn't hesitate to use the current 3.2.1.  I've flown it on my 550 with no problems.  I think 3.2.1 is where they achieved smooth transitions between spline waypoints.  It is really nice.  I fly low and fast and it is nice.

      I don't know of any major stability problems. I have a lot of dynamic flights on it with a Trex 550 and Trex 800.  

      3.3 is in beta.  I'm very happy with 3.3 rc4 but there are still some issues mentioned above.  

      • Ok thank you sir, that helps a lot.

        - Jeff

  • I flew rc4 again on my 550.  I compared it to my 800 flying 3.2  

    3.3 is way better when it comes to smooth flight.  Here is a video.

    I only have one problem.  When I spool up the copter yaws about 20 degrees to the right (I'm used to that, it's always been that way).  But now when I switch to auto, it yaws about 30 degrees left on liftoff.  The same problem is there in loiter but not in stabilize.  

    Is this a result of the EKF or something in 3.3?  I think it's a minor example of what zhangpengsir found previously.

    one more thing: 

    Was it a design feature of a 3.2 or 3.3 to have RTL disarm upon landing even with the throttle elevated?

    The release notes aren't clear.  I like it better this way.  It just surprised me.

This reply was deleted.


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