Just built an X-quad using a Pixhawk FC , been a very steep learning curve, I flashed the unit with firmware 3.5.7 , have done all the necessary calibrations in order, even did the ESCs as well.
The problem I am seeing at present is when I throttle up all is working as it should, but when I use the Pitch/roll to it’s extremities (mode 2) then one of the motors will slow down or stop and then all four motors will shut down and then I have to re-arm the system.
I’m at a total loss here to what the cause of it… anyone have any pointers than can help me rectify this problem…
I am a relative newbie with Pixhawk and I do want to get the most out of the system…
pardon my ignorance, I come form a DJ Naza background, and as such this is all new and somewhat alien to me.
I have the craft armed in stabilize mode, I’m a tad sceptical about attempting a flight while the craft is exhibiting this (to me) strange behaviour…
had to start somewhere…LOL… just a tad worried about damage that may occur with my inexperience with all things Ardupilot
update: I disabled the crash function, now I’m able to test the motors, can’t understand why a single motor is slowing down and/or stopping when extreme roll or pitch up/down is reached… is this normal behaviour for this type of FC??
As I said it’s normal behavior. You are giving it a command but there is no change in feedback from the sensors (accels, gyros) because it’s stationary. With the motors running pick it and pitch/roll it around what happens? The motors do all kinds of things trying to stabilize the craft but it can’t because the feedback is not following the commanded action.
Assuming you have the motors in the right order and turning the right direction fly it.
"can’t understand why a single motor is slowing down and/or stopping"
hard to tell from this, but in order to recover, (level off, like I assume it’s trying to do) that sounds reasonable.
If you want to test your motors like that you can play around in acro mode (and maybe disable it’s leveling)
You may need to adjust some PID’s before autotune, but really, you just need to get to some real hovering. If you did al calibration/connections right, then there is no reason to bench-test it more.
Remember, this is a highly advanced flight control software, nothing you can do on the bench, will make a full simulation, because the acceleration, position, pressure and so on will never converge, leaving EKF in a strange state.
many thanks for all the replies, and I thank you for your patience…I’m not the brightest bulb in the box…old habits die hard, and I never realised that the Pixhawk was that complicated… will post results once I get out and do a test flight…
Just a wee update:
I managed to get out today for a first test flight… discovered that I had to reverse the pitch channel, apart from that the craft flew surprisingly well… tested in stab mode for the first flight, had the odd variance in altitude but nowt to worry about.
Tested in alt hold and loiter, all was well, though LOITER was a tad skittish (but that would be the craft adjusting for GPS), also tested RTL switch and all worked as it should have.
Perhaps a bit of calibration for drifting and an auto tune should correct things…
all in all pretty pleased with how it flew…
