T-Rex 450 Test flight -- Loiter / Guided / RTL and Alt Hold
APM 2.0 firmware 2.7.3
MediaTek MT3329 and barometer
After replacing the hidden Torque Tube Bearing in my T-Rex 450 the shifts in attitude are gone.
Everything changed to the best.
I found a great new flying field, so I went to test Loiter, Guided and RTL, Alt Hold worked always great. I planned a mission too, but the wind became too strong after a while so I will try this another day.
As you can see in the video (thanks to my lovely wife) everything worked very well.
This are the PID I used. The Nav speed is low 2m/sec which is relaxing to watch and you have no overshoots.
Thanks a lot DIY Team.
Comments
Yes you right, soo 3 high fives to the heli guys!!
Randy and all the Heli dev guys are truly heroes!
I'm just wondering how proud you are now.
This is so beautiful to see.
Hi Christoph
Yes I tried that high values of yours and it behaved too erratic.
Be carefull with the I term and the I max. As you can see I reduced that very much.
The I force ramps up very fast to I max if the heli can’t reach the target in a certain time, because of a wind pushing it out and then you get that overshoot or oscillation.
The D force gives an initial push and then ramps down fast, like you kick a ball into the target; this is much more calming but introduces a bit noise. The P force is just proportional to the distance to the target.
With lower values it might get pushed a bit further of target but it comes much softer back and the system calms down quickly. And yes the same applies to ALT Hold. As you can see in the video my Alt Hold is calm when flying a bit erratic, it raises a bit and softly cams down again.
My advice, get I max an I down use a medium P and quite a bit of D.
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.
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.
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 :-)
Perhaps i should order another apm for my kds 450 quiet?
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!