Hi everybody,
First I am sorry for my bad english.
I have set up my 650 Quad with a Revo and LibrePilot.
It flys really well and smooth and dont mind about windy conditions or fast flying.
But sometimes it suddenly begins to oszilate, then i have to land, disarm and rearm, so it flys still again.
I have flown around 30 till 40 times now.
And have crashed it now for the 3rd time, because it suddenly tilts to the left.
If that happens the right motors make a short fullpower burst, so it turns around 90° to the left and crashes down.
Can it be a fault of the cc or of my setup from the software?
« Last Edit: April 03, 2016, 05:46:23 pm by FeuerVogel666 »

Re: Revo sometimes tilts to the left and crashes the Copter
« Reply #1 on: April 03, 2016, 02:09:49 am »
So I have tested a few things and this on two copters with different setups.
But let me explain this.

At first I had Problems in my 650 Copter. Sometimes it tilts to one side and I have crashed it 3 times or so.
Then I build it up with a second Revolution but got the same behavior.
To make it secure it is nothing from the other Hardware, I took my Hexacopter, and changed it from APM to Revo.
Took it in my Backyard and tested it. But it made the same (see my Video under this text).
So i took another Transmitter, but always the same.
In the meantime i had got a 3rd Revo for warranty, cause I thought the first one was broken.
So I tested this one and got still the same behavior.
BUT when I change to Basic (Complementary) it flys smoother and dont show anything from the tilting.
Does this mean ALL 3 Revos are broken or is there still an error in the Firmware or maybe an mistake made by me with the setup?

In the Video I got all Green in the GCS and flew in Attitude with Throttle on Manual and Yaw Axislock.


f5soh

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Re: Revo sometimes tilts to the left and crashes the Copter
« Reply #2 on: April 03, 2016, 12:25:46 pm »
Maybe due to vibrations and Accelerometers go crazy.

Maintain firmly the frame on ground and monitor the horizon behavior while apply throttle. Be safe !

Solutions:
- Add filtering, go to Attitude tab
- Add adhesive foam on FC case to isolate from vibrations
- Balance props.

Re: Revo sometimes tilts to the left and crashes the Copter
« Reply #3 on: April 03, 2016, 04:59:21 pm »
So, i tested a little around with higher filtering and so on.
I watched the Horizon while flying and even a while, when the Copter was standing still on the ground.
I made a log of the behavior.
Sometimes, while Copter is standing on the Ground and Motors are disarmed, the Horizon jumps around for an second and goes back on normal, but I dont know enough to figure out what is happening.
I put the Log down here, it happens to the end.
Logged while the copter stands on the Ground an is disarmed.
Sometimes this kick is much stronger, sometimes it is a little tick.
I dont know what to do now.
Where can I buy an Revo wich isn´t a clone. Best would be in the EU, but no need to be.

f5soh

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Re: Revo sometimes tilts to the left and crashes the Copter
« Reply #4 on: April 03, 2016, 05:16:51 pm »
Please edit your title: you have a Revo, not a CC3D.

All Revolution boards are clones, the last genuine board is maybe 2 years old now.


Re: Revolution sometimes tilts to the left and crashes the Copter
« Reply #5 on: April 03, 2016, 05:48:56 pm »
Ok, I have edited the title.
Ok, but where should i buy to be sure to get Boards wich are build within the specifications...

hwh

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Re: Revolution sometimes tilts to the left and crashes the Copter
« Reply #6 on: April 04, 2016, 03:17:52 am »
There's nowhere you can order from and be sure it will be a good board.  You order one and check it when it comes in to make sure it's good.  The main problem is the regulator and it's capacitor creating noise on the barometer.  The thread https://forum.librepilot.org/index.php?topic=311.0 talks about how to check the barometer.  If it's bad you either complain to the seller or fix it yourself.

I've had good luck with the one we all hate the name of, "Revolution Mini".  It's a revolution clone in a smaller form factor with the oplink removed.  You can add what they call an "oplink air" to it and you effectively have a full revolution but in two smaller boards instead of one bigger one.

jdl

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Re: Revolution sometimes tilts to the left and crashes the Copter
« Reply #7 on: April 04, 2016, 11:19:46 am »
Hi,
I'm new to the forum and a beginner in the rc multicopter world. I'd like to share my observations on a similar issue.
I've experienced similar behaviour (sudden tilts) with my copter build. Using 'next' build with I2C mag support.  ZMR250 with Revo and Beitian BN-880 GPS & Mag, Micro MinimOSD and OPLM telemetry, PIDs tuned well as far as I can judge. Generally the copter flies very well in all manual and autonomous modes. But sometimes when using INS13GPS and flying in self-levelling mode (no matter manual or auto-pilot) the copter suddenly jerks, mostly to the right and jumps up the same time. The artificial horizon in OSD goes crazy and it takes several seconds to show correctly again. Most of the times that happened (the crazy horizon) I was in RATE mode so no problems with the control of the aircraft but once it happened when landing in ATTITIDE (again INS13) and it was a nasty surprise. Luckily managed to keep the copter in the air till the attitide estimation recovered.

I've checked the telemetry records and noticed that when this happens, there is always a glitch in datastream from GPS (just missing data for a single second), this also causes the 'NO GPS FIX' message on OSD. These glitches (missing 'packets' in the continuous dataflow from the GPS) can also be observed in uBlox Control Center when on the ground. They happen very, very rare, but they do. And then the EKF estimation just goes crazy and it takes some time to recover.
It would be great to have some kind of validity filter and/or dead-reckoning for the GPS data in the Revo firmware, or in case the GPS fails, the EKF to be switched momentarily to Complementary just as a failsafe solution, till the EKF estimation is good again.

P.S. Sorry for my not-so-good English, it's not my native language and I know it's poor but I hope - understandable.

Greetings to all the developers and members of this forum, I hope the LibrePilot will continue to improve, it's a great project!

f5soh

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Re: Revolution sometimes tilts to the left and crashes the Copter
« Reply #8 on: April 04, 2016, 11:50:54 am »
Hi Jdl,

Quote
The artificial horizon in OSD goes crazy and it takes several seconds to show correctly again.

Vibrations.

Maybe due to vibrations and Accelerometers go crazy.

Maintain firmly the frame on ground and monitor the horizon behavior while apply throttle. Be safe !

Solutions:
- Add filtering, go to Attitude tab
- Add adhesive foam on FC case to isolate from vibrations
- Balance props.

jdl

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Re: Revolution sometimes tilts to the left and crashes the Copter
« Reply #9 on: April 04, 2016, 11:59:00 am »
I've seen the same to happen when sitting on the ground, motors off, no vibrations at all. Never observed crazy horizon in Complementary mode, only in INS13. No matter in the air or in the ground. I've no record of OPLM telemetry showing the problem when sitting still on the ground, I'll try to make one.

P.S. Props and motors are balanced, revo is mounted on a 3-4mm foam pad. I'll try some filtering... Still suspect the loss of GPS data (and maybe momentary jump of reported GPS coordinates to some distant point).

The problem is not reproducable intentionally, playing with throttle doesn't affect the horizon at all.
« Last Edit: April 04, 2016, 12:04:02 pm by jdl »

f5soh

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Re: Revolution sometimes tilts to the left and crashes the Copter
« Reply #10 on: April 04, 2016, 12:05:28 pm »
Horizon moving a little while steady is normal.

See https://librepilot.atlassian.net/wiki/display/LPDOC/INS13+-+GPS+Navigation

f5soh

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Re: Revolution sometimes tilts to the left and crashes the Copter
« Reply #11 on: April 04, 2016, 12:18:02 pm »
Sometimes, while Copter is standing on the Ground and Motors are disarmed, the Horizon jumps around for an second and goes back on normal, but I dont know enough to figure out what is happening.
I put the Log down here, it happens to the end.

I replay your log, at end your GPS do a big position jump around 4meters maybe that cause the spike in attitude estimation.
There is two traces in screenshot, the raw GPS trace and estimated position from INS13
« Last Edit: April 04, 2016, 01:16:17 pm by f5soh »

jdl

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Re: Revolution sometimes tilts to the left and crashes the Copter
« Reply #12 on: April 04, 2016, 01:52:17 pm »
I managed to dig an example in my telemetry records that shows how momentary 'No GPS Fix' causes horizon jerk. Here is portion of GPS Input data extracted to CSV:


date, Time, Sec since start, Connected, Data changed, .Latitude, .Longitude, .PDOP, .Satellites, .Status
2016-04-04, 14:39:59.422, 126.976, 1, 1, 425112365, 274762658, 1.5,  14, Fix3D
2016-04-04, 14:39:59.649, 127.203, 1, 1, 425112269, 274762389, 1.5,  14, Fix3D
2016-04-04, 14:39:59.799, 127.353, 1, 1, 425112177, 274762121, 1.5,  14, Fix3D
2016-04-04, 14:40:00.12, 127.566, 1, 1, 425112086, 274761853, 1.5,  14, Fix3D
2016-04-04, 14:40:00.199, 127.753, 1, 1, 425111996, 274761583, 1.5,  14, Fix3D
2016-04-04, 14:40:00.367, 127.921, 1, 0, 425111996, 274761583, 1.5,  14, Fix3D
2016-04-04, 14:40:00.429, 127.983, 1, 1, 425111907, 274761313, 99.98999786,   0, NoFix
2016-04-04, 14:40:00.812, 128.366, 1, 1, 425108864, 274763301, 1.709999919,  10, Fix3D
2016-04-04, 14:40:00.884, 128.438, 1, 1, 425108864, 274763301, 1.709999919,  10, Fix3D
2016-04-04, 14:40:01.12, 128.566, 1, 1, 425108802, 274762996, 1.649999976,  11, Fix3D
2016-04-04, 14:40:01.209, 128.763, 1, 1, 425108738, 274762696, 1.709999919,  10, Fix3D
2016-04-04, 14:40:01.357, 128.911, 1, 0, 425108738, 274762696, 1.709999919,  10, Fix3D
2016-04-04, 14:40:01.409, 128.963, 1, 1, 425108676, 274762414, 1.649999976,  11, Fix3D
2016-04-04, 14:40:01.579, 129.133, 1, 1, 425108616, 274762138, 1.649999976,  11, Fix3D
2016-04-04, 14:40:01.799, 129.353, 1, 1, 425108557, 274761859, 1.649999976,  11, Fix3D

And a screenshot of Scopes page while replaying the log in GCS.

Flying on gyros only at this moment so nothing unusual in AccelState scope but AttitudeState shows clearly the wrong estimation.

jdl

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Re: Revolution sometimes tilts to the left and crashes the Copter
« Reply #13 on: April 04, 2016, 02:14:08 pm »
... and another screenshot of that exact moment, with "Raw GyroState" and "Raw magnetometers" scopes, if this can help.
« Last Edit: April 04, 2016, 02:17:56 pm by jdl »

f5soh

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Re: Revolution sometimes tilts to the left and crashes the Copter
« Reply #14 on: April 04, 2016, 02:35:08 pm »
That clearly a GPS glitch.
14sats, no fix and next only 10sats.