Discussions

Too sensitive throttle in Stabilize mode and copter not holding position

Posted by Tom Judkowiak on June 1, 2012 at 11:14pm

Hi,

I've recently put together a quad with DJI FlameWheel 440 frame, ESCs and motors and APM 2.0

I have few problems:

1. in Stabilize mode it's extremely difficult to hold altitude: when I slightly increase the throttle to avoid crashing the copter continues to ascend and even small change causes it to descend and it bounces up and down. I tried changing the controls but they seem to have no effect so if anyone you guide me which ones to pay special attention to, that would be great. (note: in loiter mode it's much more stable).

2. the copter also seems to have problems with holding position despite solid blue GPS light. I managed to put it to stable hover in stabilize mode and then switched it to loiter mode then without touching the sticks observed what's it doing - the copter was drifting to random positions within 15-meters radius - I would expect better from GPS (note: it was open space and no wind at all).

Any help would be very much appreciated

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Replies

Matt Gaige June 4, 2012 at 12:44pm

Many people use the throttle curve adjustment on their Tx, so that in the mid range they are able to flatten out the "ramp" to make it less touchy. If you have not calibrated your ESC's that may help also. Make sure on your TX settings that you are using the full range of the throttle BEFORE you calibrate the ESC and do the Radio Cal in the Mission Planner.
T3

Stephen Zidek June 4, 2012 at 12:31pm

I would also appreciate some help with these questions, especially question 1!

My quad is very difficult to fly without altitude hold on. One little "notch" on the throttle is the difference between shooting up into the air or plummeting back down. I would love a way to have finer control of the throttle.

I should mention I generally fly heavy payloads. 5000 miAh battery with a digital camera and dog tracker gps "collar". Th quad uses the 880kv motors and the 20A ESCs.
- Praneel Acharya > Stephen Zidek August 1, 2015 at 10:43am
  
  Similar problem. Reading the reply for this post I now did ESC calibration which wasn't done. It was deadly just as you described. It was too bouncy. At the last of the video you could see it. Though it was flown by an expert, (I was camera man). We can clearly see the problem. I will record a video after ESC calibration.
  
  Same problem as explained in 1. at the end
  - Praneel Acharya > Praneel Acharya August 7, 2015 at 4:44pm
    
    I somewhat solved the problem after increasing the value of thrust curve mid-point % from initial value from 52 to 70. Oh yes I also did ESC calibration. What it basically did was, let's say when I use 50% of my throttle it rises to 50 meter now with 50% throttle it rises to 30 meter. Got the point.
    
    Still there are the problems like drifting towards left and so on. I will work more to stabilize it.