Tuning Pitch/Roll offsets. How to read the Log file data

Hello All.
I have done the pitch/roll settings on the bench, and test flown my heli as stated in Ardupilot first flight tests section. However, I am confused as to how I read out or graph the angle needed to hold heli in position as stated here: “Load the helicopter with its normal payload, and hover the helicopter in no-wind conditions in Stabilize flight mode. Land it and pull the log, noting the roll angle and pitch angle that you had to hold with the stick to keep the helicopter from drifting.”.

What parameters do I look at to determine the pitch/roll angle needed? I assume I need to compare command versus real angle, but I have no idea how to do this. I need some help please. Thank you.

My setup is: Goblin 580 heli, Pixhawk 6C Mini with M9N GPS, Ardupilot 4.5.4. Not sure what else is needed for you to help me. I tried to include my log file but it was too big. How do you guys upload large log files?

Use google drive or dropbox or service of your choice and post a shareable link.

This video will help a lot


Okay, hopefully I shared this correctly and didn’t give access to the keys to my kingdom. Please let me know if I did. I hate to show my age, but this is the first time I have used Google Drive to share anything.

Hopefully this has the data required so someone can teach me what I need to do for tuning. Thank you in advance.

@Allister , thank you for your reply. I just watched the video and it is helpful, but wow! There is a lot more involved in setting up and using this system than what I am used to with the BeastX, IKON, or the NAZA-H. It’s definitely not plug-n-play. At least now I have a better idea what to look for. Thank you and have a great day. :slightly_smiling_face:

Naza-H … I did a bunch of builds way back when on the Naza-M. You’re right, this isn’t going to be as plug and play, but it can do so much more than those controllers it’s mind blowing.

I’ve done plenty of builds on multi rotors and planes, but I’m just getting into helicopter builds. I’ve got a couple OMP M4s on the bench at about a similar point to where you’re at. (There’s a Vario as well, but I’ve put that on hold until I get the OMP figured out) So I can only offer so much before one of the smart guys is going to have to step in.

To do the full check you’re going to need to make some parameter changes and then re-fly it in stabilized mode. These changes won’t impact any performance, but will allow logging of the data needed to do all the analysis that Bill talks about in the wiki and his videos.

LOG_BITMASK,145149 #added bitmaks for Fast attitude and PIDs
INS_LOG_BAT_OPT,4 #For Notch filter tuning you'll want to see the pre and post filter data
INS_LOG_BAT_MASK,1 #Also for notch filtering, we just need data from the first IMU.
ARMING_CHECK,1 #Make sure all the arming checks are working.  If this is giving you trouble then we need to figure out what's getting in the way.  

Based on experience in this forum, you want the full arming checks on, it will save you a lot of time and money in the long run.

A couple of things aren’t adding up in the log so before I shoot my mouth off can you clarify, was that log from a flight or just a bench test?

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@Allister , thanks for your reply and info about the other parms I need to setup. I will try tomorrow and do a shorter flight test. After watching the video he said fly for 30 seconds, not six minutes, Lol.

The data was from an actual flight.

I am looking forward to be able to use the rich features of this software once I know what I’m doing.

Are you on FaceBook or other platform where I can follow your OMP builds? If you are posting any.

Have a good night.

I’d also look into the current meter since I’m guessing it’s drawing more than 1.4 amps in a hover. Voltage also looks suspect since I’m guessing you’re running at least 6S, not 3S. (voltage is showing around 12 volts)

Vibration levels look good so that’s awesome.

There were some issues with the GPS and baro reported altitutde, but I’m thinking that since the arming checks were turned off that the EKF position wasn’t happy before take off and it adjusted during the flight. It may take a while before everything is happy to arm. Be patient, it may take longer than you expect the first time. If you have telemetry messages on your radio (Yaapu) or a laptop connected via telemetry radio you’ll get a reason why it won’t arm. Note those if you’re stuck. If all else fails and you just can’t get it to arm, and you don’t have any way to get the messages then set LOG_DISARMED to 1 and try again. Normally logs are only created after arming, but this way you’ll get a log file right from the start and we can see the messages if you’ve attempted arming and it failed. Gives you something to troubleshoot with.

This is the most social I get online. I gave up facebook, and twitter a few years ago. One of the better decisions I’ve made for my mental health. Once I’ve made some noteable progress with the OMP I’ll share any goodies here. It seems like a good entry path for an ArduCopter Helicopter so maybe others might be interested.

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@Allister , totally understand being unplugged from the social madness. I’ve stopped watching most news channels other than for weather updates.

The current and voltage are correct because I am only powering the Pixhawk and it’s peripherals. I am actually running the motor on 10S, and I’m using a 3S to power the Pixhawk. I also have two separate voltage regulators so I have redundant power sources.

I’m glad the vibs look good.

I may have taken off too soon knowing I didn’t need GPS for stabilize flight mode. I do plan to add a telem radio, just haven’t got there yet. I will have to recheck the arming because I thought I had it on. I wasn’t able to do any testing today because I was tied up with another project. Tomorrow I will have time to play and study and stare at graphs, Lol.

Thanks for your help. Have a great night.

Then please setup voltage and current monitoring on the propulsion battery. You will avoid unpleasant surprises and involuntary autorotation training :sweat_smile:.

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@LupusTheCanine , why do you suggest that? I have always used a separate battery for my flight controls. The reason I do this is incase a propulsion battery failure I still have power to the flight control. But you may know something I haven’t thought of, so I welcome your feedback. Thank you.

Simply put without voltage and current monitoring on the propulsion battery neither you nor the autopilot have any idea of the actual state of the battery which makes it impossible to take early action if the battery isn’t performing as expected.


@LupusTheCanine , that makes good sense for sure. I am just so used to flying without any of the features Ardupilot has. I have set all my heli flight times so that when I land I have 50% battery left.

I will at some point add the propulsion battery to my monitoring. Right now I am just trying to get through the setup and testing for first flights and tuning.

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The flight battery will have an influence on the setup. It will allow you to create calibrations offsets for the compass, as well automatic warnings and failsafes if there are battery issues.

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@Allister , I don’t understand what you mean with the flight battery allowing compass offsets. Can you please explain? Thank you.

Once the heli is flying you can use the data from a flight to run MagFit compass calibration. If you have accurate current data then it will create a dynamic offset that will adjust the compass calibration as the level of power related interference changes in flight. This way your compass is going to be more accurate no matter what you’re doing in flight.


This system works so well that now for all my builds all I do is get a “good enough” compass calibration on the ground that lets me get the machine in the air. Then I will run a MagFit calibration and never look back.

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@Allister , that is very interesting info about the compass calibration. I’ll admit I don’t understand how that works, but I will be researching it so I can hopefully understand it better.

When I first setup my heli I just did the large model calibration because I’m working inside a metal building. Yesterday I stole the Holybro telemetry radio off my robot project and put it on my heli. Then I went outside and redid the compass calibration as noted in the wiki page. Then I rebooted everything, took off in stabilize mode, switched to position hold mode, and flew around my front yard. The heli flew great and would hold position very well when I let go of the sticks. That made me happy for sure because I have been struggling with all the filters and tuning steps in the wiki. I really just want to fly the darn heli, and not have to get an engineering degree to do so, ha-ha…

Are you located in the USA, and would you be open to doing a phone call to educate me? I do not know if we can send private messages between members. If we can I give you my number if you’re willing to talk (teach me). :smile:

Your best bet is to post here because then you’ll get more people who can help. Like I said, I’m good with Ardupilot in general, but I’m new to Heli tuning so I’m not sure I’d be the best guidance.

Starting with a helicopter as your entry to Ardupilot might be a bit steep but not impossible since you already have a heli background.

Bill has done a great job with the wiki. Really just take the time to read it over and watch the videos. Take it step by step. And don’t be afraid to ask questions because there’s a lot going on.

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