@KFayal
Yes, it was very hard to tell on the Youtube video if you really turned IRIS to the left or if that left turn was the effect of one or more props stopping. Guess with the raw footage you are in a much better position to determine that.
There wasn’t any changes in yaw or the corresponding RC channel either. With that it really looks like the motors and log files stopped just before you were trying to initiate the left turn. That more and more looks like a battery issue or brownout.
I’m not aware of a method by just looking at total voltage of a pack to determine whether it’s still good or not. But a few methods that come to mind, which give good indications about the state of a LiPo:
Balance charge the LiPo, run it down to about half of the capacity. Check the voltage of each cell. If a cell is discharging a lot faster than the others, then it was probably damaged.
Well the crashed IRIS is on the examination table down there at 3DR in San Diego. I guess its up to them if they let me know if they can determine a cause. The new one arrives tomorrow and although my instincts are to treat it carefully and not fly it more than 10 meters away from me, I’m going to put it through the paces like my first one - after a couple of initial “break in” hover flights.
I’ve been without the drone for almost 2 weeks now and man, I miss getting it up and flying.
Thanks for all the help. I’ll reply here once I find out anything from 3DR.
I also broke the long legs and I’ve almost finished a good design for them. I’ve been trying to get new legs from 3DRobotics for 2 weeks now with no luck.
Anyways, feel free to order some from Shapeways or something if you still need new ones or I could print you some for cheap.
Well, it appears after examination that this was my fault. The summary judgement was:
The pilot commanded full output power from the vehicle late in the flight causing an almost fully discharged battery to fully collapse to a level where the power supply to the autopilot could not be sustained. The autopilot and motors subsequently turned off in mid air.
Contributing Factors
The pilot commenced the flight with a battery that was not fully
charged.
There is a history of a battery or multiple batteries being damaged by deep discharging on several previous flights.
The pilot may have been using a battery that had previously sustained
damage from deep discharging.
So, here is what I take from this. I HAVE to be watching the droid planner to keep an eye on my voltage levels while flying. At first, I thought that the Droid Planner was just a thing you would use if you want to fly autonomously. It appears that flying with the gimbal will require me to NOT be able to rely on the battery failsafe, or I should set the failsafe to a higher voltage than 10.5VDC, maybe 10.75 (unless someone else has a recommendation). The reason is because sometimes I have the IRIS at such a height that it draws down so much current just to maintain the automatic descent.
These are my recommendations to everyone who flies with the gimbal, take it or leave it.
A failsafe should not be something that you rely on as part of your regular operations. As the name says, it should be a last resort when previous manual steps fail.
I would recommend to change the failsafe operation to LAND instead of RTL (although I learned that LAND takes longer than I thought).
Furthermore I would recommend to increase the failsafe voltage. The level needs to corresponds to the weight of the rig your flying (with or without gimbal), the height of a typical flight (and thus how long it takes you to get down to ground in a controlled way), the battery you’re using and the buffer room you want to have in there. I don’t have a perfect answer for a level yet.
With regards to the GCS:
My primary use case for this is indeed listening to the battery percentage announcements and keeping an eye on the voltage.
Assuming that you start with a full stock LiPo (3500 mAh) my rule of thumb is: Fly home when the battery is at 30%. Ensure that you are safe on the ground before 20%. But keep in mind: I’m flying without long legs and gimbal.
The RC transmitter/receiver in the IRIS is actually a two-way radio link and could provide information about battery voltage back to the remote. I just wish, the voltage of the IRIS could be displayed on the RC this way along with a configurable audible voltage alarm.
Scanning this forum, I haven’t seen any mention of a possible mechanical failure as a possible cause of this crash. Have you opened up the case and checked out the ESC board? If you get a chance, take a look at it, and make sure the little black cube-shaped voltage regulator hasn’t come loose. That happened to me in February, most likely as a result of an earlier crash weakening it. The effect was exactly as your video shows.
I have briefly looked at log file and for me it seems rather to be a battery problem. In the crash the battery was having 10.8V and when the engines stopped it has recovered to about 11 volts. This is normal.
if you take a look on the CTUN Throttle in and out you will see that the throttle input and also output is fallen to zero. that comes close to set the transmitter in off position or an transmitter related error. Also if it was beeping this is always not a good sign.
Normally in this case the Failsafe should take control, but onestly i haven’t tried out and don’t know if this is working properly.
Could you send the Configuration file from the iris ? just export it from mission planner -> Full parameter list.
Since the Transmitter is also fully open source an there are newer Releases for it with bugfixes and so on, how can we update them to the newest version ?
What i noticed too is that the Compass Offset is set to zero, this is how the iris comes from the production you need always before first run to do the compass calibration. Use the Mission planner starting from version 1.3.0 and forward for calibration.