Hey folks,
I have an APM2.5 running on a SK450 with whatever the latest version of arducopter firmware is. Using a ublox gps and 900mhz radio telemetry modules with 2.4 for rc control.
In stabilize mode the quad works great. I fly up to about 5m altitude switch on loiter and then it behaves erratically, flies sideways, down tips and crashes. Done this twice.
I though loiter was meant to 'lock' the quad in position and only move with inputs from me.
Anyone got any ideas - i think the hardware - escs, motors, all the acceloromters, gyros, gps etc seem to be working fine in stabliize - so it must be something else?
Thanks so much for any help.
Replies
Haha, sorry - here is the IMU .log and the mission planner .tlog for the same flight i think. Do they open up alright? Thanks for your time trying to figure this out much appreciated.
2014-04-14 14-37-31.log
2014-04-14 14-34-57.tlog
I read up on vibration interference. However wouldn't too many vibrations also affect stabilize? Because stabilize is perfect, i can get it hovering without going anywhere.
Also i cant do anything else really to limit vibrations, as when i built the quad to limit vibrations the APM is mounted on foam tape corners, then on foam rubber block then in foam tape corners again. If vibrations are getting through i cant think of a way to stop them.
Hello again, i have tested altitude hold and it does not work as intended either.
I was up about 5 meters and switched altitude hold on and wham the quad took off up through the sky up to about 100m!!!
I saw my gps had a hdop of about 1.7. However is the altitude shown in the flight data page meant to be above the starting position (where switched on APM)? Because it showed approx 80-90m when it was sitting on the ground?
I flicked it back on stabilize and flew it home no worries, but i would like to get the more complex flight modes working.
Would it help if i had a look at the logs to see what was happening? Which logs would yield the most info - does mission planner save all logs?
Thanks
I have been checking out the logs (i am still new to mission planner) and it appears as if the altitude is totally whackey! Assuming the units on the GUI on the right is the altitude and when i graph the altitude log it jumps all over the place. For example in a few seconds it goes from 200 to 50 in a second and goes up and down, then goes up to 800 then down to -200 and carries on up and down?!
This cant be right can it?
Is the GPS used in stabilize mode, because stabilize works perfect? Also is the barometer used in stabilize or altitude hold - i have heard that prop wash can interfere with the barometer...
Thanks
Here's a pic of one of the logs.
alt log.jpg
I haven't tested altitude hold yet as when i switched over control in loiter it could have killed my quad! Do you mean the compass calibration test - which it completed fine. With loiter, do i just fly up to a certain level then switch it on and it will lock in position unless i put throttle above half way or nudge it around the other axis? I don't see how even if the compass was off it would cause it to drop out of the air - wouldn't it just not lock the yaw axis?
Thanks
I was thinking perhaps my GPS has poor signal, although it says GPS 3D Fix. How do i check if it has a hdop under 2? Thanks
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