LibrePilot Forum
Users => Vehicles - Helicopters => Topic started by: attituderc on March 18, 2018, 06:01:07 pm
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I have set up the heli, ever thing seems to be working properly,except...
When i move the collective it moves up to mid stick, then jumps to the bottom and starts moving up again. It is really weird. Throttle is on 6 pitch is on 2.
(link fixed by TheOtherCliff)
Video link. https://www.youtube.com/watch?v=gs--B_2qIAU
Does anyone have any ideas?
Thanks Brad
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Looks like it stripped the video link.
https://youtu.be/gs--B_2qIAU (https://youtu.be/gs--B_2qIAU)
Thanks
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I can imagine that happening if you have "idle up" function enabled on your transmitter.
LP assumes you are using a simple transmitter type without using a throttle or collective curve.
Look at GCS Input->RCInput page while you are doing this. Does the collective channel move like you describe? If so, your transmitter is actually sending that.
(you must use youtube.com, not e.g. youtu.be etc.)
Also, if using PPM, you must be careful to keep pulse widths from being too long and not to use more than 9 channels with PPM. Individual control channel width should be 100%, not e.g. 140%. It can be that it jumps to the next channel so that for instance your collective is sometimes actually connected to the yaw (or other) control.
I have a mismatched set of transmitter brand and receiver brand where it gets full left rudder when I give full throttle, but works fine at 85% throttle.
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Actually had same problem, and solved it by making curve2 (which I assume is collective curve)
be V shaped instead of lienar / see here https://forum.librepilot.org/index.php?topic=4190.msg28466#msg28466
This I have figured out by observing the channel values and movement. Not sure about the magic involved, but somehow the mixer that handles collective does not like the the rc channel value going from -1 to +1.
I suppose this could be solved with TX side curves too.
I should also mention I have "collective passthrough" option enabled.
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I am using SBUS and the the the collective and throttle curve are a straight linear progression, no fancy curves. Should i let the CC3D handle all the curves? I have the option to change to PPM would that be better for the controller?
Checked the radio output and it seems it it is sending the proper outputs.
Thanks, for the quick response. I really want to get this working on this little 180cfx.
Thanks,
Brad
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I have set up the heli, ever thing seems to be working properly,except...
When i move the collective it moves up to mid stick, then jumps to the bottom and starts moving up again. It is really weird. Throttle is on 6 pitch is on 2.
(link fixed by TheOtherCliff)
Video link. https://www.youtube.com/watch?v=gs--B_2qIAU
Does anyone have any ideas?
Thanks Brad
Hi Brad,
Did you set the center value of the collective channel near to minimum? Thats mandantory, if you do not, the swash plate usually jumps. And i recommend to set the swash plate travel during the swash plate adjust procedure from -20 degree to + 20 degree. if you dont do, you will not have enough travel, because all values are mixed together with a 50% factor. And no curve on the remote, as cliff said.
Udo
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I set the collective through the process but it never recenters after the min step? Not sure what is going on with this thing?
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Seems to be having an issue around mid stick. ONLY on this heli. Mid stick is working fine on every other heli i have with no glitches.
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I set the collective through the process but it never recenters after the min step? Not sure what is going on with this thing?
Can you upload your uav file here?
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Looks like it is already attached to first post. :)
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:)
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@attituderc,
Try this
. in GCS, Config, Remote control, on the settings for Collective: set the Neutral value to 205 (or just slightly higher than your Min value of 205, like 207).
. in Vehicle, Helicopter, Basic settings, CCPM options, un-check the Link Roll/Pitch option.
... thats basically what Udo said previously.
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Here is what I have tried.
Switched to PPM (thinking SBUS was an issue) No help but had to reset all the values.
The Min is 1000 max is 2020 with PPM
Set the neutral on the collective to 1002 (as described, no change)
Unchecked link picth and roll. (no change)
The collective climbs to mid stick then resets to the bottom and starts moving again. No curves set up in the radio. Could it be software version?
Thanks for your help,
Brad
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new uav file
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What I see is in your file
. the Collective Neutral is still way too large (1509, and min is set to 994, put the Neutral to 994 or 996)
. the Link Roll/Pitch is still checked.
Please chek it?
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Ok, so i missed what you were trying to say about the min. I reset that and things are acting better. I will let you know. I think that my be part of the issue not i just need to go through and reset up eveything.
Does the throttle neesd a low min too? Or just the collective.
Thank you so much.
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hi,
I have double checked what I did on my setup, and I have to correct myself, it is not V shaped but this:
(https://forum.librepilot.org/index.php?action=dlattach;topic=4190.0;attach=7309;image)
This has given me nice positive and negative collective.. or at least I believe it does so :) (the thing actually flies).
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Need both throttle and collective to have neutral set very low. Reasons:
I think what we have learned is that for the default setup, when the throttle stick on the transmitter is above zero, but below neutral, then all the channels are set to their neutral settings.
It sounds like you had a low throttle neutral, but a middle collective neutral, so the first little blip of throttle made the collective servo go to it's neutral (middle), but adding more throttle stick made collective go to where you want collective to be.
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@Brad,
I dont think you need to redo all the setup.
Just remember every time you need to redo the transmitter calibration you need to put the neutral back to min.
That change will cover it.
(but of course you still need to level the swashplate travel and set up correct angles for cyclic and collective :) )
Let us know how things develop!
@mr_w,
when the Collective Pass through is checked, in Vehicle, Helicopter, Basic settings, CCPM options,
then I don't think it matters how that curve look like. It will use whatever the transmitter is sending right?
I think the setting of the mixers (Collective, Pitch, Roll) just to the right, will have most impact on a good enough range of the collective.
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@karla
Yes the curve actually matters, it is applied to collective channel. I suppose it would be helpful if there was title above the curve which says so.
It looked like for -1,+1 range, collective goes (with jumping) twice through all positions, so without digging further into the code, I just assumed that something in mixer is doing abs(collective) (or equivalent), and then applied this curve to scale -1,+1 to 0,+1.. which kind of fixed it. I am also pretty sure that this can be properly fixed somewhere else. Just thinking if this is common issue with heli setup? (this is my first and only heli with LP so far, but I have done plenty of multirotors and couple of wings).
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Thanks a lot for verifying that the curve still has impact!
Its not really any issue when setting these Helis up (other than the default collective setting neutral to mid of min and max).
Since, once you check the Collective Pass through, then you will work on the transmitter only and adjust it to what ever that curve is looking like, until you get the desired movements on the pitch angels on the rotor.
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@karla
Yes the curve actually matters, it is applied to collective channel. I suppose it would be helpful if there was title above the curve which says so.
It looked like for -1,+1 range, collective goes (with jumping) twice through all positions, so without digging further into the code, I just assumed that something in mixer is doing abs(collective) (or equivalent), and then applied this curve to scale -1,+1 to 0,+1.. which kind of fixed it. I am also pretty sure that this can be properly fixed somewhere else. Just thinking if this is common issue with heli setup? (this is my first and only heli with LP so far, but I have done plenty of multirotors and couple of wings).
My first heli too, and I have 3 other CC3Ds in multis.
I'm just about done setting up a 470LM with an Atom. I too had collective jumping. Through trial and error I found that mine wanted the collective neutral to be maxed. At any low setting it would jump to mid collective when the stick got down near the lowest...or max negative collective. I messed with curves for hours, nothing took the jump out until I tried maxing the collective neutral (actually max -5). My curve is -1, -.5, 0, .5, 1.
Tx is a Taranis. Now I have 3 modes on switch SD (could program for all 6, but don't see the need), 5 throttle settings on 2 switches 0, 25%, 50%, 62.5% and 75% (switches SA & SB set up by logic switches and special functions in Tx), SF as a master arm switch which not only arms the CC3D (set on Acc0), but over rides throttle output to -100 (or zero throttle) when not armed, and when armed it enables the throttle outputs from the 2 switches (again, using special functions and logic). Hope that made sense.
Now that the controls all work proper and react proper to frame movements I can level the swash for real with the tool then fine trim everything.....and then say a long, long heart felt prayer, lol.
After getting her airborne I'll be able to adjust those throttle outputs to suit her.
I want to say a big
THANK YOU
to all those that have come before me working out these heli issues.
Josh
aka The FlyNFool
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:o This thing is whacko. Don't know if I'm going to trust a $500 'copter to it.
So after doing a little fine tuning the collective jump came back, with a new oddity. When I get to that spot on the collective where it glitches, my rx (an X8R in D16 connected via Sbus) quickly reboots, of course sending everything haywire.
So tracking down why it was glitching and jumping the collective I ended up putting the collective input neutral back to same as collective low. Watching the input screen I could see it was not my Tx (Taranis) jumping it's output signal, which meant it was the Atoms problem in interpreting or processing the input signal. It simply does not like a full -100 signal. Changing the collective curve in LP proved no help, so I tried clipping the bottom of the output signal in the Tx output menu. -95 is what it ended up smoothing out at. No more jumping, no more Rx drops. Sooo -95 to 100 seems to have made it happy (er).
Any clue as to why the Rx would reboot when this anomaly occurs? What a serious problem. Makes me scared to put her in the air.
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Sounds like a bad 5V voltage sag when you put a big load on your servos.
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Hi TOC,
Servos were not binding, that I'm certain of. But none the less it seems that could be the case. I'm running 8.4v. Atom did not reboot. Must have been a heck of a load, where ever it went.
Swash plate tool came today, woot! Will work on it some more this weekend.
Thanks :)