After numerous bench tests, re calibrations, and more bench tests I was finally brave enough to take my 3DR quad out for it's first flight -albeit tethered. I did some initial outdoor ground testing in which I brought the throttle up to the point of takeoff but noticed that the quad was showing a tendency of tilting forward and right so I killed the throttle, ran this test several times, and decided I didn't want to attempt the takeoff having no clue what might happen. So...
I threw together a quick test rig on nearby deserted swingset to evaluate what the quad would do when in the air. The video clip below shows the outcome... Without any stick input the quad wants to fly forward and to the right. I was able to counter it with stick movement and fly the quad around the rig without too much trouble but if I stopped countering the roll/pitch it would try and wander (this is evident in the video when you see it start to move sharply to one side).
I've ruled out motor rotation, wiring, and prop direction via another round of tests to verify everything's good. That leaves me suspect of:
- mis-calibrated radio
- mission planner radio calibration
- Radio Trims?
- Leveling (although I leveled before this flight)
- Auto-Trim (I've done none of this yet)
I also found the following in a FAQ post:
"My copter yaws right or left 15° when I take off: Your Motors are not straight or your ESCs are not calibrated. Twist the motors until they are straight. Run the ESC calibration routine."
I've calibrated the ESC's many times over the learning process how often should I need to re calibrate them? As for motors not being straight... I've checked that they're secured properly to the frame, not sure what could be off.
I'll be continuing to test but thought I'd post my experience, my swingset test rig, and humbly ask for any pointers on what to look at.
My Setup:
- APM 2.5 running 2.73 firmware
- Stock 3DR Frame
- 850k motors w/ 10x47 props
- Stock ESC's
- Sonar, 3DR telemetry, ublox gps
- 9x TX modified with FrSky module + er9x
Replies
Well I just got back and I must say overall this was not an enjoyable experience.
Firstly the copter seems very unstable, and skitters all over the place.
This seems to get worse with time too, though really I blame my PID's which are presently at default.
Secondly my yaw control does not seem to work whatsoever, and trying to rotate the copter makes it pitch like crazy and get really out of control.
So back to tuning PIDs I suppose.
Hey as I'm having a very similar problem what exactly did you do to fix this issue?
An Update:
My suspicions were correct. I proceeded to make sure all curves and mixes were set properly on my TX. Then Ran the er9x stick calibration on the TX.(main screen, hold down to get to radio setup, calibrate) Then I connected up mission planner and ran the TX calibration there. Just did a quick lift-off test in the living room and the quad made a very calm almost straight up 4in lift before I put her down. Much better than previous tests.