APM 2.5 loiter wanderer

I am new to this level of UAV.

I have a Hex X 2.9.1, 800kv, 12x4.5, 5000 3S, AUW 2500g. 8+ min flight, all balanced and centered

Hovering in Stabilize mode is good, but it seems to want to pitch slightly. forward or back. I have to stick hold position consistently. I have Auto Trimed several times. Does not seem to help. When I switch to Loiter, it immediately wants to quickly wander away, not in a way of overshooting target, but like a 5 year old in a candy store. I am afraid of attempting RTL for that reason. 

Please help with suggestions 

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Replies

  • have u checked ur compassmot. mine was doing the same till I got the compassmot down to 9%. loiters great and all other features. gd luck.

  • I believe the accuracy is determined mainly by the GPS, connect to MP preferably on laptop and go outside with both, goto flight data and I believe status tab to the left will be the hdop and sat count as well as watching the GPS tracking on the map, make sure you lock at least 7-8 sats with an hdop of 2.5 or under and that your GPS track is not making any big movements. PIDS will only help keep it in place as other forces try and move the copter..
  • Okay so I've got the loiter mode to work a little bit better it actually turns and comes back to a direction but the target area seems to be about a 30 foot radius how do I tighten up the target radius?
  • I usually get the blue blinking light on my GPS with in about a minute. Am I locking on to all satellites or just a few. Do I need to wait longer?
  • Stick trims should not be required.  Center everything up including the trims and sub trims and do the following:

     

    Insure that the APM is exactly on the same plain as the copter arms.  Insure the motor shafts are perpendicular to the plane of the copter arms.  Then use a bubble level on top of the APM for the accelerometer calibration to insure the acc level calibration is in fact done level.  Only after doing the above will the APM be level which will result in the copter being level eliminating the no wind drift you are experiencing.

     

    Also if you are using a GPS requried for the auto modes, pay attention to the hdop which should be under 2 for a precise RTL and auto land with minimum of drift. This will require 8 or more sats probably and a good GPS.  

  • I have calib. ESC's, balanced props, and APM is mounted on foam ear plugs. Accel calib ??? Is that different from thestandard calibration of the board
  • Have you done ESC calibration? Mine did the same thing (or sounds like it ) before I did that.
  • Vibration? Have you calibrated the accelerometer? What's your GPS strength?
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