Loiter dips in altitude and sluggish moving

Log Analysis -- deprecated Copter Logs -- deprecated
1

Hi all,

Test flight again tonight

Lifted off in stab. Rock solid hover with next to no movement. flew around a bit then got some height. Switch to loiter mode and position was held good, but copter looses altitude a little then gains it back and so on, but seems to hold position very well. GPS good fix and <1 hdop.

While in loiter mode i tried to move around and its very sluggish and twitches allot. Why is this?

Viewing my own logs i can see i sort of have a issue with vibrations. XY isnt to bad but could be a little better but Z is just in limits but a bit to close to the edges and does go over now and again.

What causes Z vibrations? Props? Nothing is touching the APM board and is mounted on a proper apm holder with rubber stumps each end, will attach picture soon

The altitude issues in loiter is deffo down to vibes but why sluggish moving and twitching? Is it a PID issue or will vibes effect this?

Attached bin file for viewing. Ignore EKF issue, compass fell off in light, now fixed hehe
onedrive.live.com/redir?resid=F … file%2cbin

Cheers
Paul

2

Tested today in position hold. Very good position hold and easy to fly around in. Still a bit bumpy up and down. But so rapid movements.

I tried to add a bit of mass to apm to help with vibrations but looks like it’s made things worse to me.

Attached picture of my apm mounting. Still need to confirm prop balance but I’m just running in vibration limits.

Anything else I can try for vibration reducing?

3

What helped me a lot was to first make sure the props are balanced. I further went as to balance the bells on the motors as well. That made a huge improvement in performance, especially with alt hold and pos hold…There are plenty of videos on that. In your picture the rubber band is just tightening the flight controller closer the vibrations. Hence why it got worst… You may also ain’t to look into some Kyosho Zeal Tape. I have read that a little goes along way. Every frame and setup is different so it’s very difficult to say exactly the problem. I say start with your balancing and check your logs after and compare them to before. I’m sure you will see a difference for sure…

Sent from my SM-N920V using Tapatalk

4

Thanks for reply

Iv balanced both motors and props. I was surprised how bad they were. Going to test it tonight and see. Also removed the band.

Paul

5

Sweet come back let us know!!

Sent from my SM-N920V using Tapatalk

6

Well went out again tonight for a 10mins flight vibes seem boarderline on the x and y and z is still high

Quad dont act strange really, maybe a little bit up and down but its manageable

Is there anything else that would effect Z that i could look at?

Cheers

7

I wonder if the frame is what is vibrating on you… Have you tried mounting the APM without the “shock absorption mount”? I ordered one and ended up removing it and just stuck it down with 3m tape. Just a thought…

Sent from my SM-N920V using Tapatalk

8

I went back and read your whole post… You say you get a pretty good alt hold? Have you done an autotune? The twitchiness could indicate pid tuning as well…

Sent from my SM-N920V using Tapatalk

9

I did get pretty good alt hold but I also has pretty decent vibes. Theno I had a little crash into a tree. I’m starting to wonder if I have damaged a motor or theses props I have are to heavy. That’s all that’s changed since good vibes. Will heavy none flexible probs wreck vibes?

Auto tune is my next thing. Got it doing everything else to a OK standard

Cheers
Paul