Replies to This Discussion

Permalink Reply by Eddie Weeks on February 1, 2012 at 7:57pm

Yes I had the same problem with 2.2x so today

I flew 2.3 today with two different Tri-copter...   tail servo is now working...

But..there are times when the tri would yaw 90deg out of the blue... with no input from me..

This has been going on for many versions...   Its seems to become more common as the flight time increases.

or let is sit on the ground and then rearm it.. 

Can't beleive no one else is haveing the yaw problem

Eddie Weeks

www.jetlens.com

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DeveloperPermalink Reply by Randy on February 2, 2012 at 6:11am

Eddie,

     Actually we do see that issue now and then, even Chris has seen it I think.  It's a rare but persistent bug that is tough to track down.  If you have logs of the flight that would be interesting to see.

-Randy

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Permalink Reply by Eddie Weeks on February 2, 2012 at 8:55am

I don't have the xbee so I don't have a log.. But I think I found the problem...

I managed to get it to yaw hard ever 10-20 sec or so... In stab I could just sit there for

1-2 min... no problem.. no yaw ... Then I would push the nose forward ~20 deg and it would do it

as the pitch came back to level...   It would not yaw hard...one direction on time... then another direction.. ...

So I unpluged this....

https://store.diydrones.com/GS407_U_Blox5_GPS_4Hz_p/spk-gps-gs407.htm

and it never did it again... after 10min of flying...  All in Stab

That GPS gives +- 32000 readings on the alt... ?

Eddie

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Permalink Reply by Don Brooks on February 2, 2012 at 9:42am

Eddie, do you have a magnetometer?

Also GPS altitude is sketchy at best. I don't think it's even used in APM. The values you are seeing could just be raw data values.

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Permalink Reply by Eddie Weeks on February 2, 2012 at 9:47am

I had a mag... but that was the first thing to go...

I took it off months ago...   I have a bunch of xbees here... trying to figure

out how to put one on the Tri..

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Permalink Reply by Don Brooks on February 2, 2012 at 9:57am

My understanding is that on a copter of any sort, to use GPS you must use a mag. Without it, then it may be calculating it's bearing based on GPS position, which is much less accurate than a mag. That could be the source of your frequent and predicable yaw changes.

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Permalink Reply by Eddie Weeks on February 2, 2012 at 10:05am

I agree %100 but this is all in Stab Mode..

I have not been comfortable in any other mode yet..

When the mag was installed... It did not know where north was anyway..

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Permalink Reply by Don Brooks on February 2, 2012 at 10:15am

Again I could be mistaken, but even stab mode uses current bearing to stabilize the yaw. The only mode that navigational data is completely disregarded, is rate (acro) mode where it only uses the gyros.

DeveloperPermalink Reply by Randy on February 3, 2012 at 6:25am

@Don,

    yes, you're right.  there's no point having a GPS without a mag...well, it will allow you to see where the copter went in the logs and even real-time if you have an xbee...but by itself, a GPS will not allow LOITER or any other UAV-ish features work because, as you say, the mag is required to determine your bearing.  We don't use the GPS at all for bearing because a GPS's bearing willl actually only tell you the direction you're moving..it won't tell you the direction your facing.  So if the copter were rolled over to the left and moving (for example) west...it would tell you that it's bearing is west..when in fact, the front of the copter is facing north.

    anyway..in case that's not clear...the short answer is the autopilot features require a mag.  :-).

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Permalink Reply by Eddie Weeks on February 2, 2012 at 10:08am

Correction...  t would yaw hard... One direction one time... then next time the other direction..

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Permalink Reply by Ross on February 2, 2012 at 2:52pm

Eddie...do you use the "stock" PID settings or do you have them tweaked out?

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Permalink Reply by Eddie Weeks on February 2, 2012 at 4:14pm

Stock... I changed on Roll_P and Pitch_P from 4.0 to 3.2.. thats it..

I will tell you what... A large Tri-copter with 1m legs.. Is really stable.. !!!

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