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Old Aug 28, 2012, 11:37 AM
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Copter tilts to side before starting to fly

Hello,

we have a problem with our multwii quadrocopter. It tilts directly at the start to a side.

Our copter has an aluminium-carbon-frame, wich is three times screwed and 35cm long. As mainboard we have an Arduino Mini Pro with a Drotek 10DOF as IMU.
Our motors are improved emax gf2210 with Turnigy Plush 12A as ESCs.

We have set the right sensor directions already after the manual on the multiwii.com site. Also we have calibrated the gyroscope manually with a sender on hopefully main level and there we have calibrated the ACC with MultiWiiConf, too.
The ESC are calibrated to the right throttle range via the new option in MultiWii 2.1 and all four have the same settings (with high timing and nimh).
As we checked the propeller should be balanced and the frame shouldn't have much vibrations due very strong screws.
The pitch, roll and yaw from the sender in normal position is at 1500 +- 3.
We checked also that the motors are connected in the right order (opposite site in the same direction and neighboring in different direction), we also put the propeller every time correct on the motors.
Our copter is a + copter.

But every time, when we start it and give more and more throttle it tilts to one side (wether front-left, like in the video, or front-right).

We captured it on video, so you can see it here:

http://chisaw.de/projectDemon.avi

We also toked pictures of the copter:

http://chisaw.de/IMG_1486.png
http://chisaw.de/IMG_1487.png
http://chisaw.de/IMG_1488.png
http://chisaw.de/IMG_1490.png

Could it be, that the PID-values have to be changed? (currently standard value). Because it seems that it tilts so the lower side an when its on a floor its normally that it goes higher on the higher side, but normally multiwii should correct it at the stard, when it goes flying, or? Maybe it correct it to slow.
Or have your some other ideas, what it could be.

Sorry for my english, but i hope you understood it.

Greets,
projectDemon
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Old Aug 28, 2012, 11:43 AM
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Are you taking off with autolevel enabled? That needs to be trimmed manually in air, after the quad is trimmed in ACC mode.

Also, give it some throttle to get it up in the air. Quads do not like being in their ground effect, and will fly a little wonky until they gain enough altitude to get out of it. Give it a quick burst of throttle to get it up in the air WITHOUT autolevel enabled. Right not it looks like it's taking off a little weird because of one of those 2 issues.
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Old Aug 28, 2012, 12:05 PM
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Go outside and give it some throttle! This isn't an inside toy.

Get on some short grass, give it the beans and be ready to CSC
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Old Aug 28, 2012, 12:09 PM
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Ok, i beware a crash, but when you mean i should give it more throttle, i will do.
What is that with the level mode? Should i deactive the acc and fly first in acro, calibrate the acc in fliegt and then fly in level mode?
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Old Aug 28, 2012, 12:31 PM
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Quote:
Originally Posted by projectDemon View Post
Ok, i beware a crash, but when you mean i should give it more throttle, i will do.
What is that with the level mode? Should i deactive the acc and fly first in acro, calibrate the acc in fliegt and then fly in level mode?
Yes. Fly in acro mode, and then when that is level and trimmed you can start trimming ACC mode. With the two not being trimmed, you're in for a quad that will be quite a handful to fly, and you cannot trim ACC until acro is trimmed.
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Old Aug 28, 2012, 12:35 PM
I never finish anyth
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All multi's require decent throttle to get off the ground, you cannot take off slowly.
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Old Aug 28, 2012, 02:37 PM
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I made a little test in the garden, but with a nearly emtpy accu. But also wenn ACC is off and i give more throttle it flips and landed on his head, but this time to the rear-right (maybe because the ground is uneven).

Here is a picture of the current MultiWiiConf setting:
http://chisaw.de/28_8_2012_20_31_59.png

It is in acro mode, when all is off including acc and head-free and so on?
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Old Aug 28, 2012, 03:50 PM
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Quote:
Originally Posted by projectDemon View Post
I made a little test in the garden, but with a nearly emtpy accu. But also wenn ACC is off and i give more throttle it flips and landed on his head, but this time to the rear-right (maybe because the ground is uneven).

Here is a picture of the current MultiWiiConf setting:
http://chisaw.de/28_8_2012_20_31_59.png

It is in acro mode, when all is off including acc and head-free and so on?
Turn everything off. Just acro mode. Try taking off.

Connect the battery with the quad upright, not upside down.
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Last edited by machina; Aug 28, 2012 at 04:03 PM.
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Old Aug 28, 2012, 04:00 PM
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You are having very typical beginner nerves. All you need to do is turn everything off apart from gyro, go outside and take off. Get the thing in the air, and try to hover.

Just to check - you've configured the multiwii in + mode. Have you configured the frame in + mode as well?
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Old Aug 28, 2012, 04:20 PM
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Thanks for the answers. Yes, the frame is configured in + mode. Like you see on the screenshot all options are off and i try to fly with the same settings, where nothing is on, except the gyro, or is there something else wich i had to deactivate. I just had nothing activated, but i don't get it in the air, it tilts. But i will try again tomorrow with a full battery (sorry that i named it accu)(also here in Germany is now night ).

Should i trim the transmitter joysticks to prevent the tilt to the direction where it want to tilt? But sometimes it tilts to another directions so i think it couldn't work with trimming the transmitter.

So, when everything is set right, it should just fly in acro mode and trimming the copter with the transmitter is only necessary only for acc mode right?

Sorry for my repeating questions, but i just want to be sure.
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Old Aug 28, 2012, 04:27 PM
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You don't need to turn anything else off. I can see it's all off in your screenshot, but I thought you said that you had ACC and CareFree on - perhaps a misunderstanding.

Once you take off, you need to be active with the right stick to keep the quad in one place. A lot of beginners expect the quad to hover on its own; it will not do that, you need to actively manage it.

Leave your trims alone for now.

When it starts to tilt in one direction, you gently nudge the right stick to correct.

If you find it difficult, you could try reducing your RC rate, to say 0.6. This will make it very docile.
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Old Aug 28, 2012, 04:51 PM
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Quote:
Originally Posted by projectDemon View Post
we have a problem with our multwii quadrocopter. It tilts directly at the start to a side.
We captured it on video, so you can see it here: http://chisaw.de/projectDemon.avi
Upload your video on Youtube, we will be able to see it.
Tilting at start is not exceptional. Does it fly well when you increase throttle ?
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Old Aug 29, 2012, 11:26 AM
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Today we tested alot of things. First we recalibrated the gyroscope and acc on a flat, even surface (measured with a water spirit level). Then we held the copter with our hands tried to "feel" if it reacts to our tilting movements.
We felt that the copter always keept moving to a specific side, regardless of the position we held it in.
Afterwards we went to the garden and tried to make it fly (at least) by applying more throttle that we used to.
We captured it on video (in Acro-mode):
Demon 05 - Quadrocopter kippt am Start zur Seite 01 (0 min 18 sec)

Demon 06 - Quadrocopter kippt am Start zur Seite 02 (0 min 9 sec)


We tried to correct the copter's position but the tilt was so strong that we couldn't.

By now we have already tested and corrected so many things and to be honest, we've kinda run out of ideas what the problem might be, because the gyroscope is calibrated on main levvel and should correct all tilts, or?
Any ideas?
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Old Aug 29, 2012, 11:38 AM
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Originally Posted by projectDemon View Post
By now we have already tested and corrected so many things and to be honest, we've kinda run out of ideas what the problem might be, because the gyroscope is calibrated on main levvel and should correct all tilts, or?
Any ideas?
Ok, that's not right at all

There are many, many things that can cause this behaviour. To get a quad to fly, 1000 things need to be right, and none of them wrong.

Common causes of flips like in your video:

- Motor(s) spinning in the wrong direction
- Prop(s) on the wrong way up
- CW prop(s) on CCW motor
- ESC(s) connected to wrong arduino pin
- Gyro data not being read by arduino
- Acc data not being read by arduino
- Gyro orinetation wrong
- Acc orientation wrong

Have you turned off the ACC for now? That eliminates that problem.

Does the GUI show gyro data? Does it look good? Can you post a video of your GUI screen while holding and moving the quad? Tilt left/right/forward/back/yaw.
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Old Aug 29, 2012, 12:21 PM
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Hi, here is the video, where you can see MultiWiiConf while we tilt the copter:
Demon 07 - Überprüfung der Sensorwirkung mit MultiWiiConf (1 min 44 sec)


While the tests in the garden the acc was off.

projectDemon
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