ggrif

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oscillations, what causes them besides too high pids? SOLVED!!
« on: November 13, 2015, 02:04:23 am »
Noob tuner here, don't be too rough on me 🙄

Quick question, what else can cause oscillations besides bad pids?

My new hex does the shimmy shimmy even with pids dialed down to almost zero.

All motors, arms, frame tight; new props, motors, esc's.
« Last Edit: November 14, 2015, 06:30:53 pm by ggrif »

Re: oscillations, what causes them besides too high pids?
« Reply #1 on: November 13, 2015, 03:01:10 am »
Noob tuner here, don't be too rough on me 🙄

Quick question, what else can cause oscillations besides bad pids?

My new hex does the shimmy shimmy even with pids dialed down to almost zero.

All motors, arms, frame tight; new props, motors, esc's.

ESC calibration is a place I like to check first. Loose FC or any thing loose can amplify vibrations and cause shakes too.

ggrif

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Re: oscillations, what causes them besides too high pids?
« Reply #2 on: November 13, 2015, 03:57:25 am »
Thanks. I'll re-cal the ESC's. FC is double-stick taped to frame.

Re: oscillations, what causes them besides too high pids?
« Reply #3 on: November 13, 2015, 05:21:34 am »
If the FC is mounted at a yaw angle, it can cause it.  If you mis-connected the ESC's by one place it can cause it.  These two will usually cause a circular oscillation like a coin does on a table after spinning and before stopping.

If all that is correct, you could try setting System->MPUGyroAccelSettings->FilterSetting to 42 or 20 (only for a test) and see if it is better.  (Set PIDs back to default too.)  That is a work-around for one of my quads and I haven't researched further.  After changing the value, you click on FilterSettings to make it blue, and press the red up arrow at the top of the screen to save it in permanent settings.  Reboot the FC to make it active.

If this helps, please post back here and tell me!

ggrif

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Re: oscillations, what causes them besides too high pids?
« Reply #4 on: November 13, 2015, 03:38:01 pm »
Something else occurs to me, I haven't yet learned how to enable OneShot on a Revo Nano Hex.

So I should take a look at my BLHeli settings since the esc's are set up for OneShot.

I'll get right on that.

mazevx

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Re: oscillations, what causes them besides too high pids?
« Reply #5 on: November 13, 2015, 05:06:07 pm »
All your props are well balanced? Does it the same in rate and attitude mode?

ggrif

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Re: oscillations, what causes them besides too high pids?
« Reply #6 on: November 14, 2015, 12:34:31 am »
If the FC is mounted at a yaw angle, it can cause it.  If you mis-connected the ESC's by one place it can cause it.  These two will usually cause a circular oscillation like a coin does on a table after spinning and before stopping.

If all that is correct, you could try setting System->MPUGyroAccelSettings->FilterSetting to 42 or 20 (only for a test) and see if it is better.  (Set PIDs back to default too.)  That is a work-around for one of my quads and I haven't researched further.  After changing the value, you click on FilterSettings to make it blue, and press the red up arrow at the top of the screen to save it in permanent settings.  Reboot the FC to make it active.

If this helps, please post back here and tell me!

LOL, that was exciting! 

Changed the filter to Lowpass 42, saved and rebooted the FC. Set flight mode to use normal pids

 Set the hex down in my driveway, stepped back 30 feet, armed, touched (maybe 10%) the throttle, hex jumped 10 feet into the air oscillating like mad, flipped inverted and I zeroed the throttle and turned off the Tx.

Only broke a shaft on a motor and prop and dis-located the rubber ducky OPLM antenna, splinted it, should be ok 😄.

Will graft a new motor on, do a reset, and learn some more!

Re: oscillations, what causes them besides too high pids?
« Reply #7 on: November 14, 2015, 02:22:43 am »
If that made it worse, then using one-shot or rapidesc in your esc's will make it better.  I thought you said that reducing the PID's didn't help enough though...

Sorry about your mishap.  :(  42 and 20 fly fine in my quad.

ggrif

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Re: oscillations, what causes them besides too high pids?
« Reply #8 on: November 14, 2015, 03:45:18 am »
Cliff, no worries, I appreciate all efforts to help. I know nothing!

One Shot setup is beyond me at this point

ggrif

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Re: oscillations, what causes them besides too high pids? SOLVED!!
« Reply #9 on: November 14, 2015, 06:40:50 pm »
Fixed!

Figured it had to be prop or motor or esc.  Changed out all props, no difference.

Checked out Output page in the GCS and BOOM, there it was, Motor 6 was at 60Hz, all others at 490. 

EDIT. THIS HAD NOTHING TO DO WITH THE PROBLEM SINCE MOTORS 5&6 ARE ON BANK 5 WHICH WAS SET CORRECTLY AT 490. this kind of mistake happens when learning by doing.  :o

I used the LP wizard to setup the hex, hadn't even looked at the Output page 'til today.

I can still hear/see some slight oscillation but I'm guessing this is due to the pids I'm using being developed on the same frame  but set up as a quad not a hex.  Plus motors and props are different.

At least it flies now ;D

Thanks again for all the help!

EDIT: Cliff, just out of curiosity I tried lowering that filter setting to 42...oscillations came back with a vengeance! Not flyable. 

So, then I tried the other end of the scale and set the filter to 256 Hz and, wow, seems to fly beautifully.  No more time to play today but didn't hear/see any oscillations during 3 minute test flight.

Rock On.  Will report any further developments in this thread. 

Would also appreciate help manually setting up OneShot on this Hex.
« Last Edit: November 15, 2015, 05:44:03 pm by ggrif »

liftbag

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oscillations, what causes them besides too high pids? SOLVED!!
« Reply #10 on: November 14, 2015, 07:34:42 pm »
If you have set motor output channels as in the other thread, you have just to set outputs+oneshot on receiver port and oneshot on the banks associated to motor servo outputs.
Then, jumper on kiss escs, or nothing on blheli escs. That's all.
Oh, you have to change your pids too ;)
« Last Edit: November 14, 2015, 07:37:48 pm by liftbag »

ggrif

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Re: oscillations, what causes them besides too high pids? SOLVED!!
« Reply #11 on: November 14, 2015, 09:38:43 pm »
If you have set motor output channels as in the other thread, you have just to set outputs+oneshot on receiver port and oneshot on the banks associated to motor servo outputs.
Then, jumper on kiss escs, or nothing on blheli escs. That's all.
Oh, you have to change your pids too ;)
OK. I had impression from your earlier post that something else was required. Thanks!

I'm learning to love my pids 😜. It was always so easy to use someone else's cloud config I never did learn much. So this Hex has been good experience for me, annoying at times, but good.

ggrif

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Re: oscillations, what causes them besides too high pids? SOLVED!!
« Reply #12 on: November 15, 2015, 05:36:57 pm »
If you have set motor output channels as in the other thread, you have just to set outputs+oneshot on receiver port and oneshot on the banks associated to motor servo outputs.
Then, jumper on kiss escs, or nothing on blheli escs. That's all.
Oh, you have to change your pids too ;)
"outputs+OneShot" is not an option on the Nano's receiver port  :-\

liftbag

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Re: oscillations, what causes them besides too high pids? SOLVED!!
« Reply #13 on: November 15, 2015, 05:54:30 pm »
If you have set motor output channels as in the other thread, you have just to set outputs+oneshot on receiver port and oneshot on the banks associated to motor servo outputs.
Then, jumper on kiss escs, or nothing on blheli escs. That's all.
Oh, you have to change your pids too ;)
"outputs+OneShot" is not an option on the Nano's receiver port  :-\
Sorry, I thought you were talking about the CC3D...
Have you tried to simply switch the motor banks to oneshot and set max to 2000 µS. That should work, without recalibrating ESCs.
« Last Edit: November 15, 2015, 05:58:32 pm by liftbag »

ggrif

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Re: oscillations, what causes them besides too high pids? SOLVED!!
« Reply #14 on: November 15, 2015, 08:12:37 pm »
If you have set motor output channels as in the other thread, you have just to set outputs+oneshot on receiver port and oneshot on the banks associated to motor servo outputs.
Then, jumper on kiss escs, or nothing on blheli escs. That's all.
Oh, you have to change your pids too ;)
"outputs+OneShot" is not an option on the Nano's receiver port  :-\
Sorry, I thought you were talking about the CC3D...
Have you tried to simply switch the motor banks to oneshot and set max to 2000 µS. That should work, without recalibrating ESCs.

Perfect, too simple!  Thank you sir.

Motors have a better sound now, kind of a low pitched hum under the normal scream.