Err: crash_check-1

ArduCopter Copter 3.3
1

Hi,

I had an expensive crash. I flew in POSHLD to the left with the stick at maximum. After 50 m ore so the motors stoped and the copter crashed destroying gimbal and damaging the camera. Somebody has helped me as far as to understand that ROLL and DesRoll differed by about 30 degrees which produced the err and stoped motors.

I dont dare to fly my remaining copters any more because I dont understand why this has happend. Usually I dont fly fast in POSHOLD only in STABILIZE.

I would be very thankfull if somebody could tell me what was wrong.
I have enclosed the log.
50.BIN (3.2 MB)

2

As there doesnt seem to be a solution to this sort of thing happening and as it is the second time with me that apm stopps motors in flight, I graded up to the last version and found out that it is now possible to switch off “crash_check” which I did. It looks as if the developers know something about the danger of this function.

3

Thanks for the info.

Have had similar situations and was watching for your resolution.

4

Hallo Mike,

I have a discussion with developers here:
http://discuss.ardupilot.org/t/copter-3-4-2-rc2-is-available-for-beta-testing/12641/8
but I still got no answer why the crash happened.

Derek

5

Hi Derek,

I am sorry to hear about your crash, however I am also a little annoyed by your unwillingness to hear what the people trying to help you are saying and the misrepresentation of the help you have already received here on the forums.

You sent me an email saying “I have a problem with Pixhawk V 3.3. The copter stopped motors while flying and the log says crash check 1. I am very worried about this. In the forum at ardupilot I am not getting a single answer how this could happen.”

I have now looked over your logs as you requested and once you sent me the links to where you posted questions I can see you have been given answers, instructions how to fix it and even a way to ignore it.

The cause, quoting Andre K, “It was unable to get desired attitude for several seconds, trigging a crash-check
(crash was detected due to the fact that it did not get near desired attitude - so it disarmed)”

And Randy, “So what you’re hitting is the crash check. There’s a wiki page about it here which describes when it can trigger: http://ardupilot.org/copter/docs/crash_check.html”

And the cause of the problem from Randy “In general it means the vehicle is quite out of control. It can happen with a very bad tune but it needs to be really quite bad.” Also implying the obvious fix of tuning the copter properly.

And the way of ignoring the cause and fixing the problem you noticed, again from Randy: “The crash check can be disabled but it’s probably best to get to the root of the control problems.”

The first thing I noticed about your copter was that it was obviously not properly tuned. I can also see that the outputs of each axis is not balanced (Rate log) meaning you have some combination of rotated arms, offset CG, or uncalibrated ESC’s.

I can clearly see your copter is only just able to fly. It may look like it is hovering ok to you but the logs clearly show that it could fall out of the sky at any time. The magnitude of the roll and yaw errors are far beyond anything I would consider reasonable.

I would suggest you take some time to tune your aircraft. I would also suggest you read up on and use Autotune. If you can’t do an autotune without suffering an esc failure then your aircraft is not airworthy. If you don’t wish to use autotune I would suggest setting these parameters after you have finished your manual tune. These are conservative parameters that will minimise the risk of a poorly tuned copter going bad.

ACRO_YAW_P,3
ATC_ACCEL_P_MAX,72000
ATC_ACCEL_R_MAX,72000
ATC_ACCEL_Y_MAX,18000
ATC_RATE_FF_ENAB,1
RC_FEEL_RP,25

I hope this helps,
Leonard