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TUTORIAL: FIX A FLIPPING COPTER

All things DJI related

TUTORIAL: FIX A FLIPPING COPTER

Postby GarethRens » Sat Aug 03, 2013 9:07 pm

Hey Everyone

This is something Iv been meaning to do but just havent gotten around to doing.
I help alot of people with multirotor related issues over email. The only thing is myself and the person with the issue are the only ones who get any benefit once a solution is found.
I therefore am going to repost all problems and solutions here on sadrones for the benefit of everyone (not to mention I can just send a link to the next person that asks ;)
Obviously I wont post any personal details, just the problem and the solution.
This helps the forum as well for indexing.

First email to forum problem-solution.

Problem

My copter flips instantly on takeoff.

Cause:

This is caused by one of three issues in 99% of cases.

1. You either have your motors wired wrong as in not going to the correct ports on the flight controller.
2. Your motors are turning the wrong way. (Hence generating upward thrust instead of downward.)
3. Your props are on the wrong motors. (A clockwise prop turning anti clockwise generates upward thrust.)
4. Flight config is wrong in software. (you are flying a + config, front motor directly in front, and you have x config enabled.)
5. The orientation of the flight controller is wrong or not centered between props.

If you orientate the controller backwards, all the signals are 180 degrees offset. This means that when the sensors think its rolling to the right and tries to level out by speeding up the right motor, it actually speeds up the left motor. This compounds the issue and finishes in a lawn mower. This is the basic outcome of all of the above issues.

Solution:

In order to fix it, you need to start at the beginning. We will do this systematically and methodically. If you are new to the game, I know how confusing things can get with all this stuff.

When in doubt, RTFM. Print out a copy of the pages that contain the mounting of the controller and the motor direction/prop direction. For illustration purposes I will use excerpts from the Naza manual and problem solve on the quad +(front motor directly in front) config using assistant software 1.8 and firmware 2.02.

MANUAL: http://download.dji-innovations.com/downloads/naza/en/NM_User_Manual_v2.8_en.pdf
SOFTWARE: http://download.dji-innovations.com/downloads/naza/NAZA_Installer_1.8.zip

CHECK ORIENTATION

assembly (Custom).jpg


Referring to our above printout. The front of the naza houses the connections to our Esc's and the back, all the other connections.
Place the copter on a desk or table with the front facing away from you. It's a good idea to mark the front with something (tape, paint, sticker, tipex, whatever)
Now look from the top and make 100% sure the esc ports are facing forward or away from you. Also make sure the controller is in the middle and equally spaced from all four props.
If this is all good, we move onto the next step.

CHECK SOFTWARE

NB!!! REMOVE ALL PROPS FOR SAFETY!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Turn on your transmitter (big box with sticks and switches ;)
Plug your lipo into the copter. Wait for bootup to finish (4 green flashes from LED means the controller is healthy) http://www.youtube.com/watch?v=IINTJpyC2Ac
Now plug the copter into the computer using its USB cable. LED will turn green indicating its connected.
Install the drivers if you haven't already. Now run the assistant and make sure it's connected to the naza. eg. MC OUTPUT MUST BE OFF with a green block around it.
Now go to the motor mixer tab and make sure quad-rotor I is selected (or quad-rotor x for X config etc.)
If it's not, select the correct config and click write.
Then exit the software and unplug the USB cable.

CHECK PORT CONNECTIONS
assembly (Custom).jpg

To make things clearer and easier will will do 1 thing at a time.
Unplug all the Esc's from the M ports.
Take the cable from the first esc, which should be connected to motor 1 or the front motor and plug it into the M1 port on the front of the Naza. ( Refer to printouts. Also it's a good idea to mark all motors/arms with their numbers and spin direction)
Now do the same for the esc connected to motor 2.
Repeat for the remainder of motors.

MOTOR DIRECTION
supported multirotors and motor-prop directions (Custom).jpg


Obviously we can't attach a prop to check, that would be slightly dangerous and end in tears.
Also it's difficult to judge spin direction without some form of indicator attached to the motor.
So we take either a small block of polystyrene or some tape and stick it on all the motor shafts.
Turn on your transmitter, then plug in your copters lipo.
Wait for boot.
Now arm the copter.
All the motors should spin, then stop after a few seconds. This is long enough to check motor spin direction.
Checking one motor at a time.
MOTOR 1 (FRONT) must turn ANTI-CLOCKWISE
MOTOR 2 (LEFT) must turn CLOCKWISE
MOTOR 3 (BACK) must turn ANTI-CLOCKWISE
MOTOR 4 (RIGHT) must turn CLOCKWISE.


The first motor is always anti-clockwise and the numbering goes anti-clockwise.
If any are turning the wrong way, reverse two of the wires between motor and esc. Colors are irrelevant, switch wires until spin direction changes.
Once you have done this and all is correct we move onto the last step.

PROP DIRECTION

Once again it's a good idea to mark your clockwise and anti-clockwise props. 1 dot of tipex for clockwise and 2 for ccw. Just make sure you mark the correct ones with the correct markings!
Now carefully and meticulously attach the following props to their corresponding motors.

1. ANTI-CLOCKWISE PROP to MOTOR 1 (FRONT)

2. CLOCKWISE PROP TO MOTOR 2 (LEFT)

3. ANTI-CLOCKWISE PROP to MOTOR 3 (REAR)

4. CLOCKWISE PROP TO MOTOR 4 (RIGHT)


Tighten them on with their respective tightening tool. Remember to tighten them fairly well, but not tight enough to do damage.
If the quad weights 4kgs and there are 4 motors. To hover it needs 1kg of thrust per motor. Pull about 1kgs worth of force on the prop adapter with your hand. If it doesn't come off, move to the next prop.

FLIGHT TEST

METHOD 1 (SAFER & POTENTIALLY MORE EXPENSIVE IN PROPS)
Put the copter on the ground with the nose facing away from you. Now arm the copter and gently increase the throttle to 25%.
The motors will spin up. If all seems good, go ahead and juice the throttle to lift off.
If it flips, cut the throttle and disarm to stop the motors instantly.
Now start from the beginning of this tutorial and double/triple check your work.
If it hovers satisfactorily then congrats and you know what you did wrong ;)

METHOD 2 (DANGEROUS BUT POTENTIALLY CHEAPER)
The following is safer to do with someones help. You control the transmitter.
Your helper holds the quad above their head and away from eyes, ears, fingers and any other sensitive
items, body parts etc. Also it's difficult arming the quad and holding it at the same time.

Turn on the transmitter, then plug the lipo into the copter. Wait for boot.
Now select ATTI MODE (ORANGE FLASH EVERY 1-3 secs)
Remember not to touch the transmitter sticks while the copter is booting!

Now keep your fingers aways from the transmitter sticks and have your helper pick up the quad and hold it above their head.
When they are ready and give you the go ahead.
Arm the motor and gently increase the throttle to 25%.
Now gently move the right stick to the right, just a little!!! Keep moving it slowly while asking your helper which way its trying to move.
After doing this in all directions and making sure it moves in the corresponding direction, disarm the copter, wait for the props to stop spinning and get your helper to put the copter down. Remember to keep your fingers away from the sticks. Otherwise you might need a new helper and additionally more props...

Now, once everyone is clear, arm the copter and try takeoff.

If it flips, start at step one again!
If not, well done and you know what you did wrong ;)

The End (of this tutorial at least)

If things still aren't working and you're 100% sure you've tried everything you know how to, you can either post the exact problem with as much detail as possible including pictures and videos here on sadrones or contact the manufacturer/dealer if you believe its a hardware issue. Most arent though.

If i've missed anything or screwed up somewhere in this tutorial, let me know and I will add/edit things.

Until next time - Safe flying!

G:)
http://www.stuffinc.co.za
We sell all kinds of stuff, including multi-rotor UAV/Drones :ugeek:
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GarethRens
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