Developer Comment by Randy on September 29, 2012 at 6:36am

Great video.  Congratulations!

That really is a great loiter especially considering you're relying on the mediatek which is a bit noisy.

I really enjoyed seeing the video!

Comment by Crashpilot1000 on September 29, 2012 at 9:27am

Perhaps i should order another apm for my kds 450 quiet?

Comment by Manfred Dickgiesser on September 29, 2012 at 11:36am

Randy Thanks

One question, why does the heli in RTL fly backwards home and did not change orientation speak turning around and pointing towards me?  Maybe too scary for some :-)

Comment by Christoph on September 29, 2012 at 1:43pm

Is your 450 flybarless?

Comment by Christoph on September 29, 2012 at 1:45pm

Very nice loiter and RTL.

I did several loiter flights now and tried to tune the PIDs, but found out that not every loiter is as stable as the one on your video. I had similar good ones, but also often overshooting ones.

Comment by Manfred Dickgiesser on September 29, 2012 at 2:34pm

Hi Cristoph

It’s the latest flybarless upgrade on my 450.

 

Since I replaced the Torque Tube Bearing everything changed.

The leans are gone at the head speed of about 2800rpm.

So the bad Loiter is mainly caused by “bad frequency of vibrations“, this I always mentioned.

I realized that at the beginning of every flight where the head speed is a little higher (battery voltage higher)  the heli tents for tiny leans and in this time loiter tents to circle, but after a minute or so the head speed settles to a lower speed and everything is just fine.

This is all I found out.

Comment by Christoph on September 29, 2012 at 2:50pm

And I realize from your settings that you use much lower I terms in general. As well much lower loiter rate p term. When I tried to lower the p term I got to much drift and oscillations. But maybe I will play with lower I terms as well.

Comment by Manfred Dickgiesser on September 29, 2012 at 3:46pm

Cristoph

That you get a drift at lower P suggests to me, you might have sometimes small unnoticed leans.

A higher P counteracts the leans more, but also causes oscillations.

As you see I also have a higher D term, this calms oscillations.

D is the counter part of I.

Have a try if your heli hovers in stab mode without interaction for quite some time, then you set for a good loiter.

Comment by Christoph on September 30, 2012 at 2:46am

What I also observed is, I think due to the high loiter rate P of 5 I am using, in case of some gusts the reaction of the heli is really harsh to compensate, leading to oscillations. As I reported before that is also in issue when the heli changes from a nav command to loiter command. Then there is a quite high loiter error, which in combination with the high loiter rate P leads to very agressive reactions. On your video I see much smaller reactions. But with a low loiter rate P I could not really get a stable loiter in windy conditions.

Comment by Christoph on September 30, 2012 at 2:49am

In addition poor alt_hold has direct influence on loiter, as another observation. Having strong reactions on alt_hold can make really bad oscillations in loiter, because the loiter corrective movement gets in worst case leveraged by an alt_hold reaction of the heli.

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