Can anyone advise me if it’s possible to tune out a left to right wiggle with my hexacopter running Arducopter 3.1? I know it doesn’t sound like a big issue but when shooting video people look for stability. I have several other copters that don’t exhibit this so I’m assuming it’s possible to get rid of it.
The video below demonstrates what I’m referring to. Without any input to yaw the copter has a slight wiggle back and forth left to right. I did an auto tune but apparently that doesn’t effect yaw. So I increased the Stabilise Yaw to 6.5 and the Rate Yaw PID to .16 .10 .01 but it didn’t seem to help. Should I have decreased the PID rather than increase it? Any other advice would be appreciated.
I’ve also attached a flash log of the flight shown in the video
Are you using an external compass or an internal one? I can definitely see the yaw wagging in the logs, and while I don’t yet know what is causing it, I know it should be able to be tuned out. I’m hopeful that someone more experienced can pinpoint the issue but I would start with the compass calibration, namely Compassmot. Have you performed the compassmot procedure? Based on the log file, I don’t think you have.
As you can see in the Yaw Tuning guide, not much should be required here, but that doesn’t mean none is required for every instance. I would suggest first that making sure you’re set with your compass calibrations as that does mix in to the yaw control, and then you could start introducing more or less P in the control loop to see if that yields any changes.
Sorry I can’t be more definitive, but if those two items don’t help I am sure someone will be able to assist further.
Are you using an external compass or an internal one? I can definitely see the yaw wagging in the logs, and while I don’t yet know what is causing it, I know it should be able to be tuned out. I’m hopeful that someone more experienced can pinpoint the issue but I would start with the compass calibration, namely Compassmot. Have you performed the compassmot procedure? Based on the log file, I don’t think you have.
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I’m using an external compass and I’m fairly sure I did the live compass calibration. But it sounds like a good idea to do it again to see if it makes a difference. I’ll let you know if it helps.
The magnetometer will still be inside the magnetic field even when externalized from the APM, so the offsets that this procedure generates/saves will help in a few different areas. I’m interested to hear how you make out after the test. Good luck!
I just did the compass mot test in the terminal and the result was 7% so doesn’t look like that’s the issue. I have recalibrated the compass offset and will be flying later today to see if it helped.
I did another test flight trying different values for the yaw stabilise setting with no improvement. On the third flight the copter became very unstable and the Tx controls appeared to be working in reverse so I had to do a crash landing. I’ve posted about that in another thread. Meanwhile, if anyone has any ideas on how to improve the yaw stability I would appreciate the help.
Could your compass orientation be wrong? Send a log with MAG and IMU enabled? LOG_BITMASK 9150 should do it.
Otherwise, try lowering the yaw gains below default. Start by taking STB down to 2 or 3. Your first step when something is oscillating is to reduce gains, not increase.