18.5" Two-blade Props with 3520 motors 400 kv
6s 11amps
EPD ESC 80 amps
Orange Cube
FPV RC Link
Hereflow
Loiter Mode
Flying via joystick in Q Ground Control
Today was my first day integrating hereflow into this drone. I started with a hover test from 2-3’ AGL. When that was fairly stable, I brought it up to 4-5’ and that’s when we became unstable followed by a soft crash (I expected a crash so all is fine).
Attached are the logs:
Thoughts on the crash:
1: Despite offsetting the X and Y location of the hereflow from the center of gravity (its about 10 cm forward of center as per the parameters I set in Ardupilot), I noticed that Q ground control shows no offset in vehicle setup. Question: Do I need to adjust offset in Q ground control even if I already established the offset in the parameters in Ardupilot?
2: Hereflow could have been dirty? It’s sitting about 2 cm off the ground when its landed and grass could have been touching it during takeoff. Morning dew could have been an issue.
3: I’ll check again but it’s possible that I set the maximum readable height of the Hereflow at 5’ hence the sudden instability between 2’ AGL and 5’ AGL.
4: When it crashed, the drone seemed intent to continue it’s tilt to stabilize. The instability seemed to have a snowballing / exponential effect so I wonder if there’s an misalignment somewhere. However, Hereflow is oriented such that the camera is furthest forwart of center–which seems to be correct.
And of course, the usual: IMU no longer aiding, IMU no longer aiding…
Log 102 at 16-18 seconds is most revealing. Appears to need optical flow calibration?
28_March_Hereflow_Crash_Parameters.param (17.8 KB)