IMU stopped delivering data

Hi, today i did 7 flight and in the last one the helicopter lost the control, i cut the motor and try to land. I took the canopy off and the vbar was blinking pink and green, in the log says Aileron sensor value out of range and IMU stopped delivering data.
What happened?

Which helicopter is it?

Could you add the full event log?

regards (EN) / Gruss (DE)

Rainer Vetter

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22.02.2020 19:44:37;VStabi Start -- LOGO 700
22.02.2020 19:44:39 Good;Scorpion ESC detected
22.02.2020 19:44:40 Good;Reset Reason: Power On
22.02.2020 19:44:40 Info;Bank 1 Loaded
22.02.2020 19:44:40 Info;Bank 4 Loaded
22.02.2020 19:44:41 Good;Motorswitch Motor Off
22.02.2020 19:44:41 Good;Motorswitch Idle Bailout
22.02.2020 19:44:41 Warn;Init Failed, retrying...
22.02.2020 19:44:41 Warn;Init Failed, retrying...
22.02.2020 19:44:42 Warn;Init Failed, retrying...
22.02.2020 19:44:43 Warn;Init Failed, retrying...
22.02.2020 19:44:49 Info;Calibration Finished
22.02.2020 19:45:05 Good;/battery/bt_1
22.02.2020 19:45:05 Good;Battery selected manually: Gens buenas
22.02.2020 19:45:37 Info;Governor Active
22.02.2020 19:45:37 Good;Motorswitch Motor On
22.02.2020 19:45:55 Info;Bank 3 Loaded
22.02.2020 19:45:59 Info;Raised Vibration Level
22.02.2020 19:46:09 Warn;High Vibration Level
22.02.2020 19:46:20 Info;Raised Vibration Level
22.02.2020 19:46:30 Info;Raised Vibration Level
22.02.2020 19:46:40 Info;Raised Vibration Level
22.02.2020 19:46:50 Warn;High Vibration Level
22.02.2020 19:47:00 Info;Raised Vibration Level
22.02.2020 19:47:10 Info;Raised Vibration Level
22.02.2020 19:47:20 Error;Extreme Vibration Level
22.02.2020 19:47:30 Info;Raised Vibration Level
22.02.2020 19:47:41 Error;Extreme Vibration Level
22.02.2020 19:47:46 Info;Off - ESC - Umin:40.6V Imax:164.8A Temp:62°
22.02.2020 19:47:46 Error;Warmstart
22.02.2020 19:47:46 Info;Bank 3 Loaded
22.02.2020 19:47:46 Info;Bank 4 Loaded
22.02.2020 19:47:46 Warn;The Cyclic Ring is active
22.02.2020 19:47:47 Error;Aileron Sensor Value out of Range
22.02.2020 19:47:47 Error;IMU Stopped delivering Data
22.02.2020 19:47:47 Good;Motorswitch Motor Off
22.02.2020 19:47:47 Good;Motorswitch Idle Bailout
22.02.2020 19:47:47 Warn;The Cyclic Ring is active
22.02.2020 19:47:49 Info;Bank 1 Loaded
22.02.2020 19:47:54 Error;Extreme Vibration Level
22.02.2020 19:49:16;VBar Logfile End -- 22.02.2020 -- 19:49:16

Is a logo 700

There was a warmstart "mid Air" - the IMU tried to restart but could not come up as fast as we need.

i had a similar issue in the past reasoned by a bad insultion of the motor wires. Could you please check motor/wires and insulation first?

Is the warmstart there on the bench when turning the heli on/off too?

regards (EN) / Gruss (DE)

Rainer Vetter

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

Für Posts und Antworten bitte einen PC und eine richtige Taststaur benutzen sowie alle Fragen vollständig abarbeiten. Nehmt Euch Zeit, beantwortet Rückfragen in Ruhe und vollständig.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Für Einzelkommunikation bitte ausschließlich Email verwenden! - PN, Messenger, Chat usw. werden nicht bearbeitet.
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I found the wires of the motor a little stripped by the rubbing with the plastic so I think that was it since I removed the blades and made the helicopter spin a good while moving servos and touching wires to see if something happened but I didn't touch the ones of the motor. In that flight log i did not see any warmstart. To learn.. what is called IMU and a “warmstart”?

Hi,

IMU is an inertial measuring unit, or accelerometer. If this sensor element sees a voltage drop, it may no longer output sensible data (e.g. stopped delivering data).
A warmstart is (like on a computer) a reset or reboot without powering down. In the VBar, it means the VBar has suffered a brief power loss (as in: loose connection, brief short circuit), in this case the VBar will restart, but without initializing the sensors again (for safety, initializing in mid-flight would cause a crash). Evidence is also the LED flashing pink.

So the warmstart is imo the critical entry in this combination, the IMU entry is probably only collateral, especially if temporally close.

In this case, it all seems to have happened very quickly:

Quote:

the log
(...)
22.02.2020 19:47:10 Info;Raised Vibration Level
22.02.2020 19:47:20 Error;Extreme Vibration Level
22.02.2020 19:47:30 Info;Raised Vibration Level
22.02.2020 19:47:41 Error;Extreme Vibration Level

> nothing in particular but the Extreme Vibration Levels—but now it happens all within the next two seconds:

22.02.2020 19:47:46 Info;Off - ESC - Umin:40.6V Imax:164.8A Temp:62°
22.02.2020 19:47:46 Error;Warmstart
22.02.2020 19:47:46 Info;Bank 3 Loaded
22.02.2020 19:47:46 Info;Bank 4 Loaded
22.02.2020 19:47:46 Warn;The Cyclic Ring is active

> within one second, the order of the entries might be confused, but we have
. motor off (switch to Idle, Bank 4 as evidence, Bank 3 was active before)
. the warmstart
. evidence of a quick acceleration or deceleration (cyclic ring)

22.02.2020 19:47:47 Error;Aileron Sensor Value out of Range
22.02.2020 19:47:47 Error;IMU Stopped delivering Data
22.02.2020 19:47:47 Good;Motorswitch Motor Off
22.02.2020 19:47:47 Good;Motorswitch Idle Bailout
22.02.2020 19:47:47 Warn;The Cyclic Ring is active

> in the next second, we have the actual crash (sensor out of range, cyclic ring) and motor off, and probably a repercussion from the warm start (IMU)

22.02.2020 19:47:49 Info;Bank 1 Loaded
22.02.2020 19:47:54 Error;Extreme Vibration Level
22.02.2020 19:49:16;VBar Logfile End -- 22.02.2020 -- 19:49:16

In my opinion, all the entries could be crash-related, must not necessarily show the cause, but are only effect.

So the cause of the loss of control could very well be something mechanical going wrong, or something disconnected/failing, leaving the VBar with not many assets and options. Extreme vibration Levels out of the blue could also be evidence.


Kind regards

Eddi

Born to fly ...
forced to work.

If i understood right maybe was not just the motor wires and also can be the vibrations bothering the vbar?

Hi,

well, as long as you do not notice anything odd, vibration does not affect the VBar in a way so it does strange things (e.g. drift more or less violently on one or all axis). It's just that Extreme Vibration entries only came up later in this flight, and closer to it's abrupt end. But they could also have been caused by extreme maneuvering. In the end, these entries are only for information (lower thresholds crossed), while Extreme can be worrisome.

An electrical problem could very well have caused this, but then, as stated, I find it all happening very quickly, within two seconds. In my mental cinema, perceived loss of control (21, 22 ... oh, something wrong), cut throttle and try to save it (21, 22 ... dang), crash ... takes more time, and the motor off action _before_ the impact (sensor out of range) not after it, or within the same second.

But I wasn't there

Cheers

Eddi

Born to fly ...
forced to work.

Ok, i will fix my motor wires and test it today. Thank you.
Warm regards

Crash again, The ultraguard was flashing slowly... i have a video post crash. Log is the same

Hi again,

and ... d*mn. I tried to figure out what slow flashing of an ultraguard (optipower? which?) could mean, but found nothing useful.
Any hints?

Did you do test-runs on the ground, without blades, but mechanics running? Any insights?

If in doubt, please let us check the unit here, if it's older (bought used, history unknown) or has seen abuse, maybe better replace it, for good measure.

But you—we—should try and investigate, figure it out, if the cause persists even after a rebuild, the next issues would be imminent.

Kind regards

Eddi

Born to fly ...
forced to work.

It happened once without blades and then it didn't happen again. Apparently depending on the servos the bec of the Tribunus fails and usually connect one or two capacitors to the neo to absorb the voltage induction generated by some types of servos because the bec of scorpion if you notice that appear more than 9.2v cut by protection.. i think is that, the neo’s are new and i bought to ralf at same time and i have two helis almost identical helis and the only difference is the servos

Hi,

hm ... earlier, receivers and flybarless were more likely affected by reverse voltages from certain types of servos (if that's the case here), now BECs are?
The VBar NEO has pretty good protection, so possibly now other components in the circuit get affected.

And more often than not, a crash is involved, but still some servo designers or manufacturers don't seem to make their homework properly—a shame.
If it's quick and strong, sell it, let the customer sort it out

Anyway, if you see issues without blades and maybe even the mechanics running, you have to do something, else you risk the same in flight.
Dangerous if it's only happening _very_ randomly, then you might feel safe although you aren't.

Just thoughts.

Kind regards

Eddi

Born to fly ...
forced to work.