X525 antivibration mount reqd? PID tuning for frame

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brewski
Posts: 483
Joined: Tue Apr 29, 2014 12:04 am
Location: Cleveland Qld Australia

X525 antivibration mount reqd? PID tuning for frame

Post by brewski »

Can anyone with X525 frame advise if antivibration mount is required for flight controller (mine is Crius SE clone V2.5). Initially it would just hop on ground until I enabled 42Hz LPF for 6050 gyro/acc then it would actually take off & hover. After a near encounter with a tree & overcorrection on my part quad hit the ground at about 30Km/hr sideways. No apparent damage except for ripped off landing leg & cracked motor mount. I did notice that the motor (2212 1000KV) that hit the ground felt rough to turn compared to the others so I put in new bearings & cleaned out some dirt.
When put back together it is jumping around like previous to 42Hz filter & takes approx. 80% throttle to lift off & very unstable.
The V2.3 firmware is standard except for filter & I have not tuned PIDS.

As I have repaired the damage I can't understand why the sudden change in behaviour with same firmware. With props off speed is pretty consistent between motors (until (I) takes effect & throttle speeds drop) & tilting quad results in consistent speed increase for the appropriate motor. The GUI sensor lines are also fairly clean.
With props, which have been balanced as best as I can there is considerable vibration when holding frame under centre & considerable noise on GUI.
I mounted FC on 8mm medium density foam & quad will not even lift from ground!

Any tips on getting the best from this frame would be appreciated. Also can anyone can offer suggested PIDS/filters that work best with this frame.

Cheers..B

nechaus
Posts: 21
Joined: Wed May 14, 2014 12:10 am

Re: X525 antivibration mount reqd? PID tuning for frame

Post by nechaus »

did you test the motors independently ?
its possible to of created a small short with one of the phases causing terrible motor performance...

you should check all motors out...


I went through something similar and it was driving me nuts... found out 2 of my 4 motors are junk... phase connection seem to be intermittently shorting...
I just went ahead and order x8 motors...

brewski
Posts: 483
Joined: Tue Apr 29, 2014 12:04 am
Location: Cleveland Qld Australia

Re: X525 antivibration mount reqd? PID tuning for frame

Post by brewski »

Hi Nechaus,

I took your advice & removed each motor on it's mount. On one motor a cable parted from the heatshrink so that was a potential cause of problem.
After resoldering connection I then held each motor & ran thru throttle range. The vibrations of all motors quite bad so this was cause of instability.
Bought 4 APC composite 10x5.5 props (out of stock of 10x 4,5 at local shop) with good quality prop adapters to suit.
I checked balance & all OK except one which only reqd small piece of cellotape. Mounted on brackets & did same test with each motor holding bracket & what a difference!
I then installed on quad & did test flight. The 5.5 pitch props draw more current than 4.5 but using 3000ma batteries will give 10-12mins flight time.
Couldn't believe the difference. Quad was much quieter & responded as I had expected it should. It now went into stable hover with less than 50% throttle.
Obviously the crap plastic props & adapters that are supplied with these X525 kits are rubbish.
Save yourself the grief & buy decent APC props and adapters from the start.
Cheers...b

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