Data for mid-size quad with M4v2 board

[Patnet]

Am I missing something? I don't really see any data for configuring a mid-range 450-size quad with the M4 board and an expander card. Like PID settings file; ARM, Starting and Max PWM settings and so on. Has anyone built one? Or is the only avialable info on Ladybird-sized quads?

[afernan]

Hi Patnet:

there´s quite a lot of mid size quad like yours shown in the forum. See this post for instance: viewtopic.php?f=25&t=3867 . Params are shared there (it uses AQ6 board but params are applicable for M4 also)

Also in the wiki / builds:
http://autoquad.org/wiki/wiki/building- ... with-kiss/

[Patnet]

Thanks Afernan for explaining, that's good to know M4 and M6 are the same specs. I'm building a Dead Cat, so not a perfect X-quad. I'll be sure to post the data when I have it.

[JussiH]

[Patnet]

Thanks, I will try Quatos. Right now I'm dealing with reversed sticks in QGC Win--and ordering some new props. My cat may be dead, but its frame is strong.

[Patnet]

How do I get the board to know the layout of the asymetrical frame? The front arms are wider apart than the rear. I know what my sines are and that's how you would do it in the KK board. But the Mixing table in QQC is in percentage values, not sine angles. Does it not matter?

[Patnet]

Anyone got any ideas?

In a non x-qaud, the motors shouldn't all turn at the same speeds as with 90-degrees front and back from the center of the FC. An example would be that you'd want to reduce throttle on the back two motors maybe. Having them close together will increase the combined power in the back creating too much forward pitch. Itr would dive--as in fact mine does.

The front two arms are 107-degrees apart, not 90-degrees. The back are 78-degrees apart when measuring from the center of the FC.

One should be able to calculate it. The Multiwii and KK boards have ways to do that. But I'm not finding anything on the Autoquad?

This issue would apply to any X-quad without a FC in the center of the X--the angles change.

[Max]

I'd start with a standard quad X mix, this should get you very close. Then examine the log -- MOT_PITCH, MOT_ROLL, MOT_YAW, and the MOTOR_x values. Those will clearly show if one side/motor is working harder than the others. Keep in mind that there may be other reasons for an imbalance -- props and motors can differ from the factory or be slightly misaligned on the frame, for instance, or the CoG might be off.

I'd be surprised if it's really "diving" because of motor mix imbalance. Not even sure what that means... it's tilting forward when it should be level? The controller would sense that and reduce power to the rear motors and increase power to the fronts. Or do you mean it's loosing altitude, or both?

To troubleshoot something like that it would be useful to post logs (zipped) and/or screen grabs of plotted relevant values.

All this is assuming the AQ is in the center of sphere formed by the motors. The controller needs to be in the center of rotation.

-Max

[Patnet]

Hi Max, thanks. The FC is centered on the Roll Y axis, but not X Pitch. That''s one reason I want to program the motor mix. Are you saying the M4V2 FC cannot be installed off center?

[Max]

The motor mix will not help the controller know that it is off-center when it is reading from the ACC/GYO sensors. So I'm not sure how far you'll get with adjusting that.

I know of a couple/few people who tried mounting the FC off-center (eg. search Ecilops (sp?) frame), but none that liked the result with stock firmware.

Theoretically you might be able to mess with the IMU calibration parameters to "move" them off-center, but I have no idea if that would really work.

IMHO your best bet would be to mount the FC in the center of rotation -- you need the CoG there anyway for best efficiency on all motors. If you want to significantly shift the CoG forward/back, you should also be looking at different motor/prop combos for the front vs. rear motors.

-Max