Jerky Loiter performance

Hi, I have trouble with Loiter. Am suspecting the Loiter PID’s but these are said to almost never being in need of calibration. I have checked and can conclude the following:

  • Flies great in all manual modes
  • Alt-Hold loosing hight slowly but recovers when flying less aggressively
  • Stable in Loiter if just keeping position
  • Good satellite reception (around 10 satellites)
  • In Loiter No tendencies of circles. Follows path perfectly straight but flying jerky so I believe no magnetic interference or calibration issue on compass
  • Missions, Land, RTL etc work good but jerky.

Any good ideas? It is a tricopter with APM 2.6

Have you ran this http://www.rcgroups.com/forums/showthread.php?t=2151318?

[quote=“philsson”]Hi, I have trouble with Loiter. Am suspecting the Loiter PID’s but these are said to almost never being in need of calibration. I have checked and can conclude the following:

  • Flies great in all manual modes
  • Alt-Hold loosing hight slowly but recovers when flying less aggressively
  • Stable in Loiter if just keeping position
  • Good satellite reception (around 10 satellites)
  • In Loiter No tendencies of circles. Follows path perfectly straight but flying jerky so I believe no magnetic interference or calibration issue on compass
  • Missions, Land, RTL etc work good but jerky.

Any good ideas? It is a tricopter with APM 2.6[/quote]

[quote=“FullScalePilot2”]Have you ran this http://www.rcgroups.com/forums/showthread.php?t=2151318?

[/quote]
I’ve never seen this software before. Thanx! I’ll give it a try and see what it can do. What is your personal experience with it?

I like this summary format. If forced me to deal with my vibrations even through my flights weren’t that bad.
Similar to yours actually. When I viewed the logs manually through MP they didn’t look that bad. I still like to use both analyzers though.

[quote=“philsson”][quote=“FullScalePilot2”]Have you ran this http://www.rcgroups.com/forums/showthread.php?t=2151318?

[/quote]
I’ve never seen this software before. Thanx! I’ll give it a try and see what it can do. What is your personal experience with it?[/quote]

[quote=“FullScalePilot2”]I like this summary format. If forced me to deal with my vibrations even through my flights weren’t that bad.
Similar to yours actually. When I viewed the logs manually through MP they didn’t look that bad. I still like to use both analyzers though.
[/quote]
The tool looks nice. Though I can’t load my logs in it because of wrong format. My logs are in format .bin and it wants logs in .log. I have some old logs in .log but they did not load correctly. Any advice? I can’t remember how I got the .log files but the latest ones I downloaded through USB cable from APM Planner under the “GRAPHS” tab. I know they can be downloaded in terminal tab as well somehow, maybe in Mission Planner? I’ll try to download them again from the Mission Planner software and see if I get .log then maybe =)

you can use mission planner to convert them, theres a button on the dataflash tab

That was great. Converted nicely but still can’t load it. Same problem as with the old logs I tried with. I am running original 3DR hardware and stable release of tricopter firmware 3.2.1 if I am not wrong. The latest at least.
[attachment=1]Screen Shot 2015-03-06 at 21.10.38.png[/attachment]
EDIT:

I got a little further when updating to latest version but seems some problem with 3.2 firmware.
[attachment=0]Screen Shot 2015-03-06 at 21.14.40.png[/attachment]

This portion of the topic is above my pay grade at the moment (LOL). If Rabbitstu doesn’t have the answer I would try over on the APM analyzer thread.

That was great. Converted nicely but still can’t load it. Same problem as with the old logs I tried with. I am running original 3DR hardware and stable release of tricopter firmware 3.2.1 if I am not wrong. The latest at least.
[attachment=1]Screen Shot 2015-03-06 at 21.10.38.png[/attachment]
EDIT:

I got a little further when updating to latest version but seems some problem with 3.2 firmware.
[attachment=0]Screen Shot 2015-03-06 at 21.14.40.png[/attachment][/quote]

I haven’t used that tool more than once yet so I can’t help on the tool. happy to look at a bin log to see if its anything obvious.

I’d love to give you one. Could not post the .log because of size of 2mb but the bin did fit, would that work for you?
I’m no pro reading the logs but it seems to follow the desired position when I look DAccX and AccX for ex or DPosX against PosX. There should be some loitering in the end but I’m not sure which flight mode every number stands for in the log. They are 0, 5, 6 and 9

OK I will have a look later

sent from my phone so apologies for any typos

[quote=“RabbitStu”]OK I will have a look later

sent from my phone so apologies for any typos[/quote]
thanx I appreciate

Hi,

My look hasn;t been that fruitful. You don’t have many logs enabled, and your log actually looks to be missing parameters I nomally look for too to see the tune. I don’t think I have ever looked at a tricopter log before…so maybe that’s a tricopter firmware thing (might build a tri next :slight_smile:).

I can see your GPS HDOP gradually improves, so some glitches maybe as the GPS accuracy improves and the copter moves to meet the updated position.

As its APM2.6 you don’t have any ekf options to tine anyway. Maybe reduce loiter P a touch and see how it looks.

[quote=“RabbitStu”]Hi,

My look hasn;t been that fruitful. You don’t have many logs enabled, and your log actually looks to be missing parameters I nomally look for too to see the tune. I don’t think I have ever looked at a tricopter log before…so maybe that’s a tricopter firmware thing (might build a tri next :slight_smile:).

I can see your GPS HDOP gradually improves, so some glitches maybe as the GPS accuracy improves and the copter moves to meet the updated position.

As its APM2.6 you don’t have any ekf options to tine anyway. Maybe reduce loiter P a touch and see how it looks.[/quote]
Thanx for looking. If there is anything I can enable to improve logs I’d gladly do it for the next flight.
I noticed that my Compass had turned a few degrees but it seemed to little to affect anything. Had it not been 3DR advice against tuning the loiter PIDs I’d tried that already. Will do for next flight :slight_smile:

having the compass off won’y help loiter, but its usually toilet bowling not jerking if the compass is off.

Having IMU enabled might help just to make sure vibes aren’t effecting performance.

You don’t noemally need to tune loiter, but it may help. Are you flying in a built up area near buildings/trees? sometimes this can affect gps.

[quote=“RabbitStu”]having the compass off won’y help loiter, but its usually toilet bowling not jerking if the compass is off.

Having IMU enabled might help just to make sure vibes aren’t effecting performance.

You don’t noemally need to tune loiter, but it may help. Are you flying in a built up area near buildings/trees? sometimes this can affect gps.[/quote]
How do I enable IMU logging? I have never changed what is or is not logged but as you said I’ve noticed before some values in the logs are empty but they also appear in many places. For ex ALT appears at least 4 times in different categories and I normally look until I find one that has some values.

The log I uploaded here was on an open field far from building or power lines. Some trees yes but not closer than a football yard away.
I normally wait to get 3D fix (whatever that means) and it is normally around 8 satellites which it gets real quick and in a short instant more it has all 10 satellites. When I see I have that many satellites I take off, but maybe I should also look at the GPS accuracy. So far just thought it was supposed to be good with that many satellites.

have a read of the wiki on how to enable logging.

copter.ardupilot.com/wiki/config … og_bitmask

OK. A 3d fix is where enough satellites are visible that altitude as well as lat and lon can be measured. If you have moved location or its been some time since using the gps the accuracey may start off lower. You can wait longer powered before before flying to hopefully get a better fix. If flying in quick succession on multiple batteries, generally the following batteries get a better fix quicker.