Flipping on Take off (NOT ESC wrongly wired)

[matster]

Just so you're aware I have had my FC working correctly (https://www.hobbyking.com/hobbyking/sto ... odule.html), before I crashed it!

Since then I have re-built my quad and now on testing it flips when I try and take off, this becomes very annoying as I'm damaging my new frame (spending more money=unhappy wife!)

The only changes I've made are as follows;

- 2.3 NAV firmware (updated from 2.3)
- The Mag was always off by 90 degrees (even with the board facing the correct way and properly calibrated and with the correct mag dec), therefore I have had to swap the mag orientation to resolve this
- the pitch and were also swapped, so I have had to modify this as well

now according to the Windows & Android GUI, it pitches and roll correctly, with the mag pointing the right way

All the ESC are correctly plugged in (must have checked this 100 times!)

The fault;
this is fairly simple, every time I try to take off, once it gets to the point where there's about to be some lift, it will suddenly flips (normally left!) violently, it will do this with or without angle mode on.

any suggestions would be greatly appreciated!!

[Hoppsan_84]

do you have any filtering on?

[matster]

not currently, should I put the 42Hz on?

[PatrikE]

It sounds like a school example of a rotated controller board or swapped pins on Esc's
Hold the copter in a firm grip and rice throttle just a little.
Move the roll and Nick sticks on the TX and feel if it reacts correct.

If you tilt the copter in any direction it should resist any movements.

Another way to check motor outputs is to use #define DYNBALANCE
Run motors one by one from the gui.

[matster]

another strange thing, according to MultiWii Wki, the acc, gyro and Mag should do the following;

How should be the sensor axis directions

TILT the MULTI to the RIGHT (left side up):
- MAG_ROLL, ACC_ROLL and GYRO_ROLL goes up
- MAG_Z and ACC_Z goes down


TILT the MULTI forward (tail up):
- MAG_PITCH, ACC_PITCH and GYRO_PITCH goes up
- MAG_Z and ACC_Z goes down


Rotating the copter clockwise (YAW):
- GYRO_YAW goes up


The copter stays level:
- MAG_Z is positive ; ACC_Z is positive

Magnetic sensors orientation
- X MAG: ROLL RIGHT = positive
-ROLL LEFT = negative

- Y MAG -PITCH FORWARD = positive
-PITCH backward = negative

- Z MAG -should be positive
-not move a lot if the multi remains flat.

however no matter what I do, I cannot get;

TILT the MULTI forward (tail up):
- MAG_PITCH, ACC_PITCH and GYRO_PITCH goes up
- MAG_Z and ACC_Z goes down

MAG Z always goes up and the orientation is still out by 180 degrees, if I get the compass to head the right way, it's completely different to what it should be!

Also with the reading acting as they should, the roll is reversed, again, I can resolve this, but it then does not match the Wiki instructions!

I was wondering if this could be part of the problem?

[matster]

Thanks for the response PatrikE, I'm very sure my ESC are in the correct locations, but I will use the #define DYNBALANCE to test them.

My quads a little too big to hold while testing, without 2 hands and a helmet!

[PatrikE]

This should be done without props!..
You can weight it down or tie it so it can't take off.

Are you sure of where north is?
It can be confusing if you sit towards south then the copter shows backwards in the gui if nose points forward.
Up on the screen is north.

[matster]

I'm happy where north is, my house is exactly south facing, so that's all fine

assuming the motor positions in the WinGUI (M3,M1,M2,M0) are position graphically where they should be, then, i'm happy the motors are plugged in correctly and rotating in the right direction.

I'll look at tying it down and testing it further!

[matster]

just confirm, that I resolved the problem, the X,Y,Z axis were off on the Accelerometer.

it was quite an arduous procedure of looking at the graphs and changing the X,Y,Z round and adding a - if they're going in the wrong direction, testing and repeat... although that's quads in all cases.

on an aside, I'm not entirely sure that for some reason it just decided to work and everything I was doing was for nothing, as I had installed a version of software that I knew worked on my quad before I changed my frame and that was flipping like crazy too... so unsurprisingly MultiWii has confused me again!