Iris+ Crash - no positive control with transmitter


I got a new Iris+ a week ago.

From the start it was not really responding the way I would expect it to.

I re-did the accelerometer, compass and radio calibrations.

Today, I took off in Alt-Hold mode and went into a nice steady hover, then switched to Loiter. It did drift a bit as would be expected as my HDOP was just above 2.2 with 7 sats. I switched back to Alt-Hold and then it started flying to its right. Even with full left roll on my transmitter was I unable to stop it from moving right. It was getting a bit far from me so I cut throttle just to get it down. This had no effect. I then switched to RTL. Also this had no effect. It just kept on banking to the right. I then swtiched back to Alt-Hold, but never managed to get any control over it. A fatal crash was the end result.

If I look at the logs, I can see my inputs but the desired roll did not change at all.

Can anybody with more experience give me some input on what went wrong?

Thanking you!

This looks like the IRIS battery issue where when you plugged the battery in you took too long to set the copter on the ground. The Gyro now thinks the copter is pitched to the left and so when you take off it will try to level itself by pitching to the right. This continues until it maxes out the motors on the left.

Do you remember if you plugged the battery in and shut the door on the ground?

Looks like you went into throttle failsafe as well.

Also there’s an error for the compass. “Large change in mag_field” but that may be due to the crash.



Thank you for your inputs.

Iseries, your comment on the battery connect issue. The Iris was level on a flat concrete slab when I plugged in the battery. I even waited for the Iris to finish the booting process before I closed tha battery door.

When I took off and went into the first hover the Iris had no intention to pulll right like it did when I switched back to Alt-Hold the second time.

I do not think this is the issue. I also did a auto analysis of a flight I did the previous day. All was GOOD.

Anybody with more ideas?

What I see is that the copter things it’s leaning 10 degrees to the left at takeoff but you say it was level.
This causes the copter to fly right because it’s trying to level itself.
The pitch goes even more negative (lean left) until the very end where it finally goes to zero.

If I put my copter on an angle and take off it knows it is leaning to the left and straights itself out.
I also had a wind coming from that direction so a have a lot of negative roll.[attachment=1]RollGraph.png[/attachment][attachment=0]RollGraph2.png[/attachment]

I had a similar bad experience. In hindsight I’m thinking what these guys are saying are true in my situation in that it was trying to correct level.

My problem was that even though I plugged in on the ground, I put it down on a slope. Flew off so hard and fast at an angle trying to correct itself I’m lucky I was able to crash it and get it back.

Make sure you put it on FLAT ground, and don’t jostle it around when plugging in battery. Don’t pick it up and turn it to face the other direction either if you realize you pointed it the wrong way without shutting it all down first.

It’s important to make sure to not move the pixhawk after plugging the battery in while it does its calibrations(red and blue flashing).

Just a note is that the most current version of 3.2 fixes this issue and you should upgrade.

I tried duplicating this issue with the current 3.2 version and was not able to.

I put the copter leaning Left at take off and it straighten right out no issues.