APM 2.5 Roll Offset - won't allow level flight - Discussions

Hi all,

I'm trying to revive an APM v2.5 which i acquired as part of "bag of bits" when I bought my first quadcopter. I've never used it, as I've been flying my quad with a Navio2, which has been working well.

However I want to use the Navio elsewhere, so need to get the APM 2.5 working if possible.

I've got it set up in the quad as per all the instructions I can find, but when I come to actually take off, the quad appears to want to flip.

I've tried applying a very small amount of throttle while holding the vehicle: The quad tries to roll quite violently, so I allow this, and it finds an equilibrium when rolled about 25 degrees to the right. If I try to pitch or roll the quad away from this position, its reaction is always to return to the same position, and the same happens when I force it to yaw.

Pitch and roll behaviour in mission planner's HUD is correct, and each axis moves in the right direction when I move the quad by hand. Importantly, when the quad is sitting level on the ground the horizon in MP is level.

I've run thorough the INS calibration and compass calibration routines several times.

I have calibrated the escs using the all in one method, and repeated it a couple of times in case I got a bad cal for any reason. So they should all be receiving the correct throttle input. When I test each motor at %10 throttle the speeds are all the same.

I've reflashed the latest supported firmware (v3.2) via MP.

I'm not sure what else to try! The quad behaves as though the AHRS has a physical roll offset, but in MP the reported roll is ~zero and in any case I would expect running through the full calibration routines would fix any biases.

Anyone know what I'm missing?

Thanks

Tom

Hi Tom.

Your situation sounds very similar to mine.

I can only say I did, today, apparently cure mine. As in my post I was using a Taranis Tx with the throttle on channel 1. This seemed to work at first glance, but in practice, as I said it was giving a frightening roll to the right, only full left roll on the stick was preventing it. In fact the stick was so far to the left I still could not pull it fully back.

However I have sorted this with a simple solution - I re calibrated the hex running and using my old faithful Futaba 9 Tx with conventional channel layout i.e. throttle on 3 roll on 1 etc. My hex now behaves perfectly via the graphs and indeed in the air.

My next step to confirm it has truly been sorted is to re set my Taranis to a conventional channel layout also.

Watch this space!

Lyn.

Replies

Tom November 3, 2016 at 3:33am

Thank you Lyn!

Switching my throttle back to channel 3 fixed the problem! I had the RCMAP parameters set properly as far as I can tell, but for some reason this was still the problem.

Seems to be throttling as it should now so I'll give it a flight test!

Thanks again

Tom
Lyn Rees November 2, 2016 at 4:28pm

Hi Tom.

Your situation sounds very similar to mine.

I can only say I did, today, apparently cure mine. As in my post I was using a Taranis Tx with the throttle on channel 1. This seemed to work at first glance, but in practice, as I said it was giving a frightening roll to the right, only full left roll on the stick was preventing it. In fact the stick was so far to the left I still could not pull it fully back.

However I have sorted this with a simple solution - I re calibrated the hex running and using my old faithful Futaba 9 Tx with conventional channel layout i.e. throttle on 3 roll on 1 etc. My hex now behaves perfectly via the graphs and indeed in the air.

My next step to confirm it has truly been sorted is to re set my Taranis to a conventional channel layout also.

Watch this space!

Lyn.

This reply was deleted.