Hey guys- hopefully you can help . Im kinda new to the APM but have been flying for a while. I finally decided to dive into some assisted flight modes and autonomous flight and while the plane takes off and flies fine in manual mode im observing the following issues when I try to toggle the plane into FBWA, Loiter, or Auto :
Loiter instantly turns the plane into a hard circle. It held altitude and speed but was described by an onlooker as “a buzzard aggressively circling a dead animal” or “plane donuts in the sky”. Definitely strange and nothing like videos of Loiter that ive seen online. Once or twice it behaved exactly like FBWA and Auto below where upon toggling into loiter it went flat out nuts.
FBWA: the plane instantly makes a hard turn attempts to do… something and then starts spiraling down outta control. Toggling quickly to manual mode and pulling the plane outta the dive seems to be the only fix.
Auto: same behavior as FBWA
The only other thing ive noticed and maybe its unrelated but ill list it just in case (I can post about it later in more detail) is that the altitude on the osd while on the ground almost always lists ~200ish ft but the Mission Planner reads correctly when connected over telemetry.
My current setup is as follows:
Bixler 2 (cog properly balanced on the wing spars and running on a 3s battery)
APM running 3.0.3 firmware
3dr Airspeed sensor
Minim OSD
UBLOX Neo-6m GPS+Compass (externally mounted on the wing)
933 Telemetry kit
Ezuhf long range control mounted on the tail
Attached below are the logs I was able to pull off the APM this morning after flying last night
additionally ive posted two youtube videos one detailing how FBWA acts on the ground so you can get an idea and another in flight where I toggle through the modes. Sorry for the somewhat crappy flight video apparently an easy cap card doesnt take to static well (ie blue screen like behavior).
I really appreciate the help and let me know if I can provide anymore info! I owe you fellas (or ladies) a beer if I can get this sorted out
First video describing how it behaves on the ground:
I’m assuming you mounted the APM in the correct orientation (Arrow forward, connectors up.)
This looks like you didn’t perform the level calibration.
Unfortunately, your log didn’t contain any data from a flight or your parameters. It looks like that log was from a quick power-on on the ground.
The issue with Altitude data in the MinimOSD is probably because you selected “Altitude” in the OSDConfig tool, which is ASL. (Not really intuitive, I know… )
Select “Home Altitude” instead, and you’ll get AGL.
Good info - Yup the apm is oriented correctly .( Arrow forward)
I did indeed level - both on the bench and in the field multiple times .
Sorry about the logs that’s all that’s was stored when I pulled them today - I may try and fly tonight and grab some more immediately after flight .
Ahhh silly osd that seems like bad wording to me .
Any thoughts on how the plane behaves in fbwa on the ground ?
Carry out this test holding the plane in your hands like in the video
Put the plane into stabalize mode, then roll it left (that is drop the left wing) the right aileron should lift and the left aileron should drop to try and roll the plane to the right to level it up.
similarly if you roll the plane right (drop the right wing) then the left aileron should lift and the right aileron should drop.
If this doesn’t happen and the ailerons move in the wrong direction then you need to reverse the controls using the rc setup page on mission planner, use the check box to reverse the controls.
Then go back to manual mode and check if the ailerons move in the correct direction using your rc transmitter, ( like you showed in the first part of your video) if they are reversed then use the switches on your transmitter to reverse them back to give the correct control surface movement.
You then need to carry out a similar exercise for the rudder and elevator.
Simples
[quote=“martyp”]Carry out this test holding the plane in your hands like in the video
Put the plane into stabalize mode, then roll it left (that is drop the left wing) the right aileron should lift and the left aileron should drop to try and roll the plane to the right to level it up.
similarly if you roll the plane right (drop the right wing) then the left aileron should lift and the right aileron should drop.
If this doesn’t happen and the ailerons move in the wrong direction then you need to reverse the controls using the rc setup page on mission planner, use the check box to reverse the controls.
Then go back to manual mode and check if the ailerons move in the correct direction using your rc transmitter, ( like you showed in the first part of your video) if they are reversed then use the switches on your transmitter to reverse them back to give the correct control surface movement.
You then need to carry out a similar exercise for the rudder and elevator.
Simples [/quote]
So it would seem this is somehow related - I took a short video which I will upload shortly but it does seem that the ailerons are going the wrong way while in stabilize. HOWEVER if I hit reverse in the RC page it just flips the problem to the other side - Meaning I the ailerons only seem to want to go one way - ie left up right down no matter which way I roll the plane (if that makes sense)
Looks like I made a newb mistake and plugged in the servos to match my setup in my RC transmitter and not the way the apm was expecting them. So swapping those around fixed the weird mixing issue.
Still confused as to how the rudder is supposed to behave when the plane rolls in stabilize mode. Should it follow suit and try to compensate or should it go the opposite direction? Currently in stabilize if i manually say go left the plane rolls and the rudder follows but if I roll the plane by hand in the air the ailerons adjust to compensate and the rudder moves the opposite way. If that makes any sense?
Yes, in any mode except manual rudder must go into the turn. With this type of airframe the mix can be turned off as the ailerons have enough authority to control the turn but it makes it a bit neater (and if you had passengers they wouldn’t feel sick )
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