Yaw counter clockwise ~ 90 deg/sec (solved)

[doppler]

I'm using Multiwii shared as of 1380 from SVN. I was flying this quad on Saturday with no issue, other than the crash that was *ahem* my fault. I had to do a little bit of a rebuild, and now after the rebuild I have a continuous Yaw counter-clockwise at about 90 degrees per seconds.

I've tried adjusting the Yaw P, I and D, Y up to 20, D up to 0.250 and D from 1 up to 23. The only affect any of this had was I which took my opposing Yaw command from the remote and kept applying it additionally, which I expected. The amount of Counter Yaw input remains fairly consistent to keep it from spinning.

Yes, the Radio input says ~ 1500 (1502) for Yaw so it's not the signal.

If there is an imbalance I thought the controller would counter it, at least at some point, it never does. Using the Android Multwii EZ-Gui I can see the Yaw action as it occurs, when I turn it manually and when it is doing it's own thing, so the gyro is working.

I checked all the wiring, it's right, I checked all the rotations, also right. I know everyone says that, trust me on this one, I've checked and checked again, I hate it when stupid errors like this bite me.

I'm at a loss, any idea's in the box and outside much appreciated...

Thanks
Andrew

[scrat]

Check your motors if they are inclined.

[doppler]

Thanks scrat, that could be possible. I mount the motors to the 1/8 thick 1/2 wide aluminum rod using zip ties, with a cork lining on the bottom otherwise you can't get the zip ties tight enough. This time I put cork between the motor and aluminum rod, and at the bottom, could leave room for the motor to shift a little.

I am finding it perplexing that the FC is not at least trying to hold Yaw, when I built my Tri (abandoned for now due to the weakness of the Yaw mechanism), it starts off with a Yaw and corrects itself fast when it gets off the ground. I know the mechanism has a more solid affect on Yaw, but the same at least try and fix it should apply.

Thanks
Andrew

[tovrin]

+1 on motor inclination. especially after a crash, my X525 had crappy motor mounts that caused the same problems after a minor crash, i ditched them and mounted my motors directly to the aluminum rods. they work fine, as long as i keep balanced props they send minimal vibration towards my board, plus my board has good dampening.

I cant imagine using tie straps and cork, but if it works...

[doppler]

Ok.... +2 on motor inclination.... I am shocked at how sensitive it is, given the way the ties hold the X mounts on the motors they actually click against the ties, so I notched two of the motors that kind of looked off in the right direction, no more Yaw....

See attached image for how the cork mounting looks, normally I just have cork on the bottom which allows the ties to clamp tighter on the motor, in theory this could have better better, it's a very strong attachment, but with the potential to move off of centre that easily I'm going back to cork only on the backside.

thanks guys, I learned something new today.

Andrew

[tovrin]

I placed both ends of a cut and drilled heavy duty tie strap in between my motor mount plate and my boom as a landing gear. it not only keeps good tension on the tie strap so it it protects my copter, but it also lessened the vibration coming from my motors.

I am real aggressive at a low altitude so i ground drag a lot, i need my motors tight, and my landing gear cheap!

ever since i did this my bird has been flying very sweet, and much more responsive. (the loss of over 150grams of landing gear helped too, im sure)

[scrat]

To both of you. Please shorten your motor shaft. They are causing a lot of vibration and they are easy to bent.