Hi,
Yesterday my APM2-equipped glider scored its 3rd tree landing, and the 2nd related to software issues if I am not wrong. A flight plan seems to have gotten corrupted.
I had my new GPRS data connection in it. The APM software had my modifications for GPRS / DroneCell but was otherwise a 2.65. I do not believe that the mods (using a modified FastSerial instance and that is all) have been the cause of the problem, as they are not related more to waypoints than to anything else, it still uses MAVLink with its checksums and all, and it was successfully flown several times before.
Before takeoff, I wanted to make a amall change in the flight plan. I tried several times to write the mission from MIssion Planner, but kept getting "an unexpected error has happened". As the GPRS data connection has some lag that the Mission Planner implmentation of MAVLink cannot handle so well, this is normal. Finally I gave it up, re-read the flight plane from the APM2 (that works well over almost any link), re-checked and flew by the original plan.
I had to skip the first waypoint, as its altitude (absolute) has suddenly dropped, on the planner page, to 106m. My airfield is at 468m...
Well the plane flew off, I had downlink, all looked OK. I noticed that is always flew a little bit off the intended trajectory, btut I ascribed this to me reducing crosstrack and some sidewind. Then I noticed that it was going to places I had never entered in the plane and did not show as waypoints on my laptop. One such place was on the other side of a mountain.. I could not do an RTH as home was lower than terrain at the current position, so I switched to the last high waypoint before home.
The APM2 turned towards the mountain at an even more direct angle, gave full throttle briefly and then cut the throttle, and dived pretty steeply for the best pine tree.
It there a known issue that waypoint list writes is not transactional as it should be? In a transaction, all effects (such as partially set waypoint lists) should be undone if there is a failure.
Has anyone heard of waypoints getting corrupted and ending up at the wrong places, maybe by a transfer transaction that went bad? Even when a re-read in the MP does not show any trouble? I'm trying to find a possibility for it in the sources but no conclusions so far.
Anyway with GPRS it was easy enough to locate the plane, and the camera had even fallen to the ground. The plane is still there, but here is a video:
Hopefully I can pull theplane and its log down from that tree today.
Regards
Soren
Replies
do you have the tetlemetry log?