Pixhawk Flips Over


#1

Hello,

Having problems with the Pixhawk on a F450 frame with 10x5 props. I am using the ‘R’ labelled prop on the CCW motors. So the F450 is an ‘X’ frame type. First arm the motor is set to go CCW, together with the prop labelled ‘R’. The next arm is CW so has a prop without the ‘R’. Third is CCW again (opposite the first CCW arm) with the ‘R’ and the last arm is CW so again no ‘R’.

The result, the frame tips and causes a crash as soon as the thrust is increased for take off. I have tried reversing so using the ‘R’ props go on the CW, this causes a failure to take off even at maximum throttle. I guess it reverses the air flow.

The writing is on the top of the blades (ie 10x5®). I have tried reversing so fitting blades with writing on the underside.

Does ‘R’ stand for reverse?

The acelerometer and compass are calibrated.

Thanks

Stuart


Pixhawk instability
#2

Hi

From the sounds of it it might be something to do with the motor order, or ESC calibration (usually the main causes of this issue). From the picture it seems that your motors are spinning the right way around, but are you sure they are connect the the correct outputs on your pixhawk? The to right motor should be connected to output 1 on the pixhawk as shown in the picture below

As for the ESC calibration, have you managed to go through this? To check if this is a problem when you arm your pixhawk and apply the throttle you should see that all motors start at the same time and assuming your quad is level, they should all throttle up at the same speed. If this is not the case you will need to calibrate the ESC’s. The video below shows you how to calibrate the ESC’s for your pixhawk flight controller.

Yes it does and the writing should be facing upwards on the props as I believe they are on your quadcopter…


#3

Hello,

Thanks for the reply. I have just tried calibrating the ESC. The feedback I get is the same (ie the tones from the PH) however when I then try to throttle up in calibration mode, only two of four props turn. Is this normal?

Thanks

Stuart


#4

Oh BTW, I have rearranged the whole thing so that the PixHawk is central ontop, dead centre, and battery is now below. I have used the reference on the ESC, it says which colour should be plugged into which channel on the Pixhawk. So I have 1 brown 2 red, 3 orange 4 white

So is S1 = Motor 1 on the Quattro 4x ESC?
S2 = Motor 2? (I am refering to what is printed on the top of the ESC BTW)

I think this is where I may be going wrong.


#5

If only two motors spin up during ESC calibration then either something is not connected properly, or two of the ESC’s did not enter the calibration mode. When you are in ESC calibration all 4 motors should spin.

Yes that is correct, however Motor 1 on the ESC does not always correspond to motor 1 on the pixhawk as it really depends on how you connected your motors as motor 1 output on Pixhawk should go to your front right motor on your quadcopter. Motor 2 output on pixhawk should go to the back left motor according to the diagram above.

I hope that helps things and does not confuse you even more!


#6

Hello,

It was odd, when I armed the Pixhawk initially, all four props were opersating, throttle up, all props spinning up to full throttle. I didnt make any further changes. I then went into ESC calibraiton mode, and only two spin. How about that! :stuck_out_tongue:

So I understand the order from the diagram. The bit that I just need to further clarify. On the ESC it says something like:

S1: Brown
S2: Red
S3: Orange
S4: White

Then next to the cables that leave the ESC for the motors is says M1, M2, M3, M4. So are S1 and M1 linked? And S2 and M2 and so on? I think you are saying they are from your reply, but could you please just confirm.

So then from that I can figure out (by using the diagram) which colour leave, needs to go in which channel input on the Pixhawk.

Many Thanks

Stuart


#7

Hi Stuart

Yes you are correct S1 is linked to M1, S2 is linked to M2 etc… I guess that is not explicitly clear according to the labels on the ESC (something we will consider changing with our next batch), so thanks for poining that out!

Hopefully you can make some more progress with your pixhawk setup and if you have any issues or question just let me know.


#8

Hello,

After correcting the leads the problem was resolved.

Some instructions for the future would be really handy for novices like me.

Thank you

Stuart


#9

Thanks for letting us know that its working. Which leads did you swap? Was it just a case of plugging them into wrong outputs on pixhawk? Or were the props spinning in the wrong direction and it was fixed by swapping the motor leads?


#10

Well I had solved the problem of the rotation from previous guidance on here. The problem was the order I’d plugged the signal wires from the ESC to the PixHawk. Had them around the wrong way!

That said, it does drift forward and to the left, but I used the trim controls on the Taranis X9D to correct that. Is that likely due to the mis calc of the accelerometer or perhaps the way I have secured it to the frame?

If there are any pics you have that show a better example that would be handy, its not very neat, but tbh its a work in progress :slight_smile: