Hey Guys,
I am using an apm 2.5 with dji 18a escs, I have arducopter 3.1.2 installed on my apm. I noticed that the quadcopter yaws slowly with time. When I arm the quad, 2 of the motors(#s 2 and 3) don't start at the same time as the others. I tried lowering the min thr in the full param list, but that didn't help. I've been doing some research and found out that the those kinds of escs (OPTO) cannot be programmed. I calibrated the escs all at once and that didn't help. But I noticed that after I was done calibrating the escs all at once, I tested them right after the calibration was complete and they were all spinning in sync! I then disconnected the battery and armed the quad and got the same issue. Any suggestions?
Thanks a lot!
Mo
Replies
With the non-programmable ESCs you'll need to set the transmitter's throttle range from 1000 ~ 1800 (it's default is probably 1100~1900).
Another possible cause of the issue is that the COMPASS_ORIENTATION parameter is set incorrectly. If you're using an APM it should be 0 with an internal compass, 8 with a 3dr gps/compass module. If you're using another type of external compass then it can take some messing around to figure out what is the correct orientation. The method is described on this wiki page (look for the words "Quick Setup Procedure" just above "Connecting to the APM2.5").
Hey Randy,
Thanks for the reply! I tried setting the range for the throttle below 1100 but I couldn't arm the quad anymore! There is another variable called THR_MIN that I tried playing with, it made the propellers spin together but one of them is slower than the others.
The compass_orientation is set to the correct value!
Here is something that I have noticed, motors 3 and 4 are the ones that usually spin slower than the rest. If that is the case it means that motors 1 and 2 which spin CCW will cause a larger CW torque. Thus the quad should yaw in the CW direction. My Quad yaws in the CCW direction which means that I either got the logic wrong or there is something else causing that! Thanks.
P.S. then the quad is hovering I cannot see whether the motors are spinning at the same speed so after a certain throttle value they might be spinning in the same direction.
Thanks a lot!
Mo.
It should be possible to arm the copter with the throttle below 1100. If the copter fails to arm it will normally display a reason for the failure on the HUD. My guess the issue is that the FS_VALUE (failsafe value) is higher than the RC3_MIN. This means you need to reconfigure the failsafe as well.
I checked that, it is not the issue. I believe the issue is with the compass on the apm rather than the motors. I've noticed that the quad sometimes yaws cw and sometimes ccw. So I am assuming that the problem is not with the motors. I think it might be the compass on the apm. I tried to re-calibrate it multiple times but I am still getting the same issue. I also noticed that when I grab the quad and rotate it, the heading takes a few seconds to stabilize on the mission planner flight display.
I had DJI 30A OPTOs that had the same problem, i outright replaced them with XAircraft 30A. but i am interested to see if some one answers your question