Underpowered side motors/individual motor trim

[Daniel_P]

I have been trying to launch my quad recently with the multiwii pro board and among all the smaller issues I have noticed a strange problem: When I arm the board and start increasing the throttle the front and back motors gain revs fine, but the left one is about 2.5 times weaker and the right one doesn't really react to the throttle at all and only starts picking up speed when the throttle is near maximum. I have tried using roll trim to first level out the side motors and then the yaw trim to level them out with the front and back, but when that's done it is so much weaker because of the trim, that even at full throttle it is not even near taking of (and I know from previous experience that the same quad in a similar setup with a different controller has about 1 kg more than is needed for taking of). If you know what is causing the motors to spin at such different speeds or have ideas of how it may be cured (maybe how to individually trim the motors and not in pairs) please tell me. Any help will be much appreciated.

[PatrikE]

You probably need to calibrate the Esc's

[Daniel_P]

Thanks!
I will try (I have tried once before and had some glitch but i'll try again... I really hope you're right and that it is the problem)

[tovrin]

Daniel, use the esc calibration tool provided int he multiwii sketch esc_calib_cannot_fly is what i think it is. read the link provided prior to using this tool because it could be dangerous if you leave your props on.

[Daniel_P]

Thanks for the tip! I will definitely try, as calibrating the ESCs manually at first seemed to have an effect, but then it all returned to the same problem, only now left and right equalised.

[Daniel_P]

I have tried it, but it didn't solve the problem, so I checked the esc's input signal with an oscilloscope and saw that the problem is not with the esc but with the multiwii itself. If you know what could be causing this please tell me.

[tovrin]

have you tried getting in the air, or just watching the motors while it sits on the ground? the motors speeds dont mean as much when its sitting idle on the ground. over some grass, try bumping it up a little and see if it will pick up.

otherwise swap motors and/or ESC with another position and see if the problem follows the motor/esc combo or stays with the location.

[Daniel_P]

Yes I have noticed the problem when taking of, at which moment it always started a mad spin and I dropped it down. I will try swappng the esc's, but I doubt that the problem will move, as the esc are getting input signals which correspond to what I would expect to cause the problem: front and back have 1700 input on 3/4 thr, while left and right have 1300 at the same problem

[tovrin]

make sure you calibrate your acc, do you have ANY sensors enabled on the gui?

[shad0wbreaker]

I have exactly the same problem, i swapped the esc's and the motors and the Esc Rear_Left doesn't react at all (always the same Position, not the esc) (with Quad_x configuration). So i think it should be a problem with Multiwii.

[Daniel_P]

Yes, acc is calibrated and definitely on, gyro - works fine in gui but I cant feel any effect from it when i tilt the quad and hold it.

[erdemms]

Has anyone found any solution? I have the same problem. All motor's rpm changing rapidly not only while flying but also in Multiwii Conf screen. I have changed my board but problem continues.

[Ringo42]

I'm having the same issue. I got 4 or 5 good flights and now the left rear motor only spins up to 1/4 power. I used the android app to watch what the multiwii board is setting the motors to and while the other motors go up to close to 2000 at full throttle the rear left only goes to 1200. I'm not sure what changed and why it used to work.
Ringo

[scrat]

What about minthrottle settings in config.h?

[Ringo42]

I replaced the weird motor and it seems to have fixed it. I'll do more testing and report back it the problem comes back.

[Rohal]

I have this problem, too. Has anyone a solution?
Its the Rear_Left ESC/Motor. I have exchanged ESC and Motor, calibrated ACC/Gyro and ESC. But the Rear_Left Motor still doesnt respond properly

Any further ideas?

[Will14]

Hi, has anyone found a solution to this problem? I have the same problem. Tried taking off and it either flips or spins and still no fix found.

[jtlust3]

I'll share my experience, hope it helps. I originally had my top_left(2) and bottom_right(3) throttle much higher than top_right(5) and bottom_left(6). I first set calibrated all ESC's to default values (I have the plush 25A from Turnigy) and set the throttle range. Google search online on how to do this, might be different for different ESCs. Then I played with the I values of my PID settings. I basically lowered the yaw I value to 0 and the roll/pitch I values to about 0.1. Play around with them and see if it helps. This made (5)'s throttle even with (2) and (3). So the only one off was (6). Next, on my Tx (turnigy 9x) I played with all the sub trim values to get my standing yaw, pitch and roll base value to 1500 exactly. The total range is 1000-2000 so 1500 is the exact middle. I had to change all 4 of the sub trim values (AIL, ELE, THR, RUD) to set yaw, pitch, and roll to 1500. This value I'm talking about is the one you will read when you are armed but not pushing any levers. Next thing I know BAM all my motors are throttled to the same values. Hope this helps some of you!

all this is with a multiwii pro uploaded with v2.1 and viewing everything with the multiwii winGUI 2.1.


-FLY HARD-