We had a crash today with one of our spray drones (running v3.6.9) which was primarily due to a compass failure. I’ve attached the log at the bottom of this post. Here is my analysis:
- The copter took-off fine and was enroute to it’s start point.
- Soon afterwards, MAG1 starts experiencing heavy glitching. At first this triggers a couple of YAW_RESETS. MAG2 reads fine the whole flight.
- Eventually, MAG1 is so degraded that the EKF failsafe triggers and the copter enters LAND mode.
- Unfortunately, by this point the copter was traveling at 12m/s and only ~4m off the ground, leading to a very high speed land that causes a crash.
I had a couple of questions about this:
- We use 2 HERE2s as our compasses/GPSs. Why is it that upon failure of the primary compass, the copter did not switch to the other compass?
- How/why did the copter reach a groundspeed of 12m/s when the WPNAV_SPEED was set to 6m/s?
I am frankly terrified by this event because it seems like compass redundancy basically did not work, which defeats half the purpose of having 2 HERE2s on the copter.
- Hexacopter running CubeBlack, Copter v3.6.9
- 2 HERE2 GNSS (latest firmware used from CubePilot) on I2C. We cannot update to CAN mode right now.
- Both compasses/GPSs are enabled, internal MAG is disabled.
Let me know if you have any questions.
Thank you for the assistance.
U021_1568211258.bin (380 KB)