AOS UL7 Evo Yaw Issue

ArduCopter Copter 4.6
1

I have a AOS UL7 Evo with a yaw issue when doing a sharp turn the copter becomes unstable and will lose a bit of height. I don’t understand what is going on as it performs well in a straight line and quick changes of yaw in loiter are fine. The issue can be seen on the enclosed log file at timestamp 15:56:54 and 15:57:13

Thanks David Ardis

2

Some of the motors are hitting min. Any time a motor hits min or max you will lose some level of control authority.

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There’s some very odd tuning.

Let’s fix the filters first:

INS_HNTCH_REF,1  # This was set at 0 so it wasn't tracking.
INS_HNTCH_FM_RAT,0.7
INS_HNTCH_HMNCS,1 # Don't need the extra harmonics, it's an AOS frame...

That should give you:

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Next, I would reset the PIDs back to defaults and follow the tuning guide either Tuning Process Instructions — Copter documentation or How to methodically tune any ArduCopter | MethodicConfigurator

Edit: I also just noticed the frame is set to V. You might consider setting it to X FRAME_TYPE,1

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3

Agree with @Allister . The tuning is not great with large overshoot particularly on Pitch. Looks like you forgot about the Rate P terms.

I’m curious about what you were configuring with the RPM parameters? What Tuning Guide did you use?
And you have Dshot why not flash the Bdshot firmware and configure for Bdshot?

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@dkemxr I am using the Chris Rosser tuning guide but to be honest i was not exactly sure what I was doing as its different from what I had done in the past. All my previous copters where 450 size or larger the EVO is a lot smaller and more powerful and my thought was better to follow Chris Rosser’s guide as the quad was designed by him.

I was also was using the firmware that came with the T-Motor Velox V45A V2 4in1 ESC

@Allister I have changed the filter setting dont know how i missed the INS_HNTCH_REF,1 value The pids have been reset and i will tune the way i have done in the past based on Tuning Process Instructions — Copter documentation .

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5

Thanks, that’s why I asked. The errors he made with notch filter configuration was the 1st thing reported here. There have been other errors reported. IMO it’s best to use Ardupilot sources for configuration and tuning.

Assuming your ESC’s support it you should flash the Bdshot version of firmware to the board and configure for Bdshot. Reset all the notch filter related parameters back to default and start over. You will not be enabling any RPM parameters.

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@dkemxr probably be better to reset the board back to defaults and start over?

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You could probably estimate an initial set of filter settings from what you have now, and then tweak as needed. But Yeah, resetting everything and starting from scratch with the Ardupilot docs is probably the best bet. In spite of errors in his ardupilot tuning instructions, Rosser’s AOS frames are well done and you should end up with a great flying quad when it’s finished.

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Yes, that’s what I would do. As @Allister suggested you should be able to get a great tune in short order. It’s not bad now there are just a few details with the PID’s and the notch filter to deal with.

It is a testament to good frame design when a craft can fly pretty well even untuned.

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