Discussions

Servo stutter

Posted by Rune Eide Hansen on July 27, 2014 at 8:30am

Hello everybody.

Me and my friend are trying to setup my T-Rex 600 with the APM 2.5 but we are having problems with the servos for roll and nick stuttering, but there is no issues when moving the Collective pitch.

We have tried numerous things like, two BEC's, playing with reciever frame rate, different reciever/transmitter, older APM firmware, digital/analog servos ect. But it seem like the problem comes from the APM itself.

What could be the problem? and what could fix this?

Video of the the problem in action: http://youtu.be/Htwj_53-4wo

You need to be a member of diydrones to add comments!

Join diydrones

apm, helicopter, jitter, servo, stutter

Email me when people reply –

Replies

Tony Gold August 25, 2014 at 10:58am

Sorry to jump into this conversation so late, and I too was not able to see the video so this may be of no help. but how old are your servos? I had a similar problem with servo twitch and even though I was using digital servos they were pretty old. It turned out that the bandwith on older digital servo signals is much wider than the bandwith on newer servos so the older servos were constantly trying to find the center point.
Rune Eide Hansen August 2, 2014 at 5:33am

Rob, did you find any revealing things in the log that might help us?
- Rob_Lefebvre > Rune Eide Hansen August 12, 2014 at 11:58am
  
  Hi Rune, sorry for the delay. I finally had time to look at this, and clicked on the link, but it's one of those crazy free download sites where you never know which download button is the real one and which has malware. Can you not upload directly to this website?
  - Rune Eide Hansen > Rob_Lefebvre August 12, 2014 at 12:00pm
    
    Sure! Here you go.
    
    2014-07-28 20-58-06.zip
    - Rob_Lefebvre > Rune Eide Hansen August 15, 2014 at 6:09am
      
      Sorry, there's no helpful data in there. PID logging is not running, nor is RCOut.
      - Rune Eide Hansen > Rob_Lefebvre August 15, 2014 at 6:11am
        
        Okay, Could you then tell me how I turn these two things on?
        
        Rob_Lefebvre > Rune Eide Hansen August 15, 2014 at 8:18am
        
        I think you'll have to use the CLI method:
        
        http://copter.ardupilot.com/wiki/downloading-and-analyzing-data-log...
Rune Eide Hansen July 28, 2014 at 1:11pm

I'm sorry for the two pling noises in the last video I didn't realize they where there until I got home from my friend.
Rune Eide Hansen July 28, 2014 at 1:08pm

Uploaded the V3.1.3 Acro fix firmware and now Acro mode works and there is also no stuttering in Acro mode!

http://youtu.be/1xq68WqVQ9c

Hope the log file works i have no idea if i got RCOut and PID logging activated, but I did set ch6 to rate.

Log files: 2014-07-28 20-58-06
- Rob_Lefebvre > Rune Eide Hansen July 29, 2014 at 8:52am
  
  Is this log showing the problem? Or it's running the acro fix code and doesn't have the problem?