Uneven Throttle Signal; Help!

[roachy]

Ok all; I have been all over this forum for the last 4 months and read damn near every thread and post regarding KK Multi and MultiWii. I bit the bullet and ordered all the parts and built my Quad-x. Components are as follows:

Futaba 6EX Tx
R617FS Rx
Crius SE
4xHobbywing 20A ESC
4xAngel A2212-13 980Kv
X525 Frame
10x4.7 props

My initial few attempts to get it off the ground resulted in uneven liftoff from the ground 3 feet), tons of drift and, lastly, a crash into the ground breaking 2 props.

Ultimately, after loading both MultiWii versions 1.9 and 2.0, using two different computers to program, it is looking as if my left rear throttle is significantly higher than the other three.

I have tried the following to troubleshoot (to no avail):
1. reprogram ESCs individually
2. Validated Crius is level
3. loaded different versions of MultiWii using different computers
4. Calibrated ACC and Magnetometer
5. Reset and reprogrammed all trim settings on my Transmitter
6. Tried many variations of minthrottle settings in MultiWii

I am currently testing with the ESCs physically removed from the equation. I am now testing with just the Tx, Rx connected to Crius, and Crius connected to computer via FTDI. I am still seeing the same issue.


If you look at the screenshot, the throttle settings are very low on right front and very high on left rear. This was taken with my throttle at mid stick and quad is level.

Anyone have any ideas? I am officially out of ideas. What am I missing?

[djrm]

Hello
I'm no expert, I've only flown my copter a few times and I havent really got the hang of it yet.
The PID settings are all 0 in the picture, did you read before taking scrrenshot?
Try holding the copter when armed with some throttle to see where it wants to balance.
Be careful, wear gloves. Experiment in Gyro only mode before activating ACC mode etc.
hth David.

[vectR]

roachy,
Have you found the cause of the uneven throttle signal? I have the exact same problem.
And I'm using totally different hardware.
The only thing I was able to do was to hack the pid mixer code in the Output section under my QUADX configuration and add an adjustment factor to each motor that more or less equalized the outputs of the motors. I did this for LEVEL mode and ACRO mode.
The copter now flies without heading off uncontrolled in some direction.
I only treated the symptoms, but I don't know why this occurs. Obviously, this does not occur with the majority of users.

[bill516]

Throttle signal will be uneven until you trim. Use Tx trim in gyro only mode use stick combination in stable mode. If you have it connected to the GUI motors running (no props) you will see the values change as you move the Tx trim, trim it so the motors are aprox equal at 50% throttle then try a test flight. Re-trim as required for hands free flight, not really hands free but so you dont need to hold a stick position. Use GUI to get approx values for stable mode trim then fly and re-trim with sticks as required.

[vectR]

bill516,
Thanks. That was the answer. It appears that adjusting trim is close to an art requiring experience and perseverance.

[bill516]

Glad to be of help, and nice of you to respond. I least I know the info I gave was correct a lot of the time you never know if the help you gave worked.

[pablochacon21]

hey guys im new building a quad and im having the same problem. what is the tx trim somebody please explain? having headaches all day

[waltr]

hey guys im new building a quad and im having the same problem. what is the tx trim somebody please explain? having headaches all day

They are the little tabs next to and under the sticks on your transmitter. Read your radio's manual to learn more.