Unhealthy AHRS and Flight mode change failed issue

Hi;

I have 3 different problems. Unfortunately, the solutions suggested for similar problems in my searches in the forum did not work for me. That’s why I wanted to ask again.

my problems
1-The vehicle direction appears incorrectly on the map
2-Continuous appearance of Unhealthy AHRS message
3-When I want to switch to Auto mode, I get a fligh mode change failed error.

I also calibrated my autopilot completely. I was able to calibrate accel, level, compass all successfully.
I tried here3 gps and f9p gps module separately. Both of these problems exist. GPS locator number is at least 12 satellites and open area. However, despite this, these errors exist and the direction of the vehicle on the map does not match the direction of the vehicle in reality. As you can see in the picture, although the vehicle seems to be standing on the vertical axis, it is actually parallel to its position.

Same results when arming is NOT disabled?

Hi;

This result occurs when the arming is active. When the arming is not active, the mode change occurs but the Unhealthy AHRS warning continues.

Based on this situation, I made some changes and I have some observations.

I think that Unhealthy AHRS and flight mode change failed are caused by the EK3 filter and the settings in this section should be made more consciously and sensitively.

First of all, I downgraded the firmware level running on Cube Orange from 4.5.1 to 4.4.0. I think the EK2 filter was canceled in 4.5.1. Because I didn’t see it in the parameter list. In version 4.4.0, parameters related to the EK2 filter returned to the list.

In the AHRS section of the parameter list, I set the AHRS_EKF_TYPE section to EKF2 and armed it again and observed. My first observation is that the Unhealthy AHRS warning has disappeared.

Then I made mode changes and the “flight mode change failed error” I encountered during these changes disappeared.

When I set AHRS_EKF_TYPE back to EKF3 and tried to change the modes, I continued to receive the flight mode change failed error and the Unhealthy AHRS warning.

I want to ask if there is something we missed in EKF3’s settings. Because I didn’t make any adjustments in this part. I installed and tried with default settings.

Hi @ramada,

The “unhealthy GPS” warning is annoying but also surprisingly difficult for us to resolve. The issue is not really that anything is “unhealthy” (e.g. broken). It’s just that the EKF hasn’t got a good position estimate for some reason.

I think sticking with 4.5.x is the best idea. The issue is not a bug or an EKF configuration error so I would leave the EKF3 parameter at their default values.

Are you testing inside? If yes, then try moving the vehicle outside where it can get a good GPS lock. Also hopefully you’re using an external compass (e.g. part of the GPS/compass unit)?

Finally it really is best if you post an onboard log. It’s hard to do much detailed investigation without a log.

Hi Randy;

First of all, I want to clear up a misunderstanding. What I meant by tuning the EK3’s parameters more precisely was that we, as users, needed to be more conscious of the settings we made. I’m sorry if it felt like I told you to do something. This was not my intention.

I do my tests in an area that is open on all sides but protected from rain. There is no difference in the number of GPS it finds in this area and the number of GPS it finds in the open area.

As for using an external compass. The GPS module I use is F9P. it does not have a compass. Later, since I thought this might be a problem, I installed Orange Cube’s here3 GPS. I did my tests with this GPS attached. You can view the logs file below.

This log file is created when 4.5.1 firmware is installed and EK3 is active.

This log file is 4.4.0 firmware installed and EK3 is closed, EK2 is active.

Hi @ramada,

It looks like the arming checks have been disabled (ARMING_CHECK = 0). This is almost always a bad idea because the arming checks will warn you of many configuration issues with the vehicle. Could you turn those back on? Worst case disabling one or two checks (if you’re sure there is not issue) may be OK but disabling all is nearly always a bad idea.

Here are some more questionable settings

  • AHRS_EKF_TYPE = 2 should be changed to 3
  • I guess there is no external compass on the vehicle?
  • EK3_SRC1_YAW is set to 2 (GPS) but the GPS_TYPE = 1 (Auto). I guess you’re trying to use the GPS for yaw but I suspect you might not have seen the setup steps here?
  • FS_THR_ENABLE = 0 meaning the RC failsafe is disabled
  • PILOT_STEER_TYPE = 3 (direction unchanged when backing up). Normally it is best to leave this as 0 but the description is here

I think I’ll leave it there for now but if you can look into these areas and try again and post another log after that I’ll have another peek.

Hi @rmackay9

I would like to report some improvements.

First of all, I upgraded the firmware level to the latest version, 4.5.2. Then I made my adjustments as you suggested. I haven’t been able to do a driving test yet, but after these settings, the Unhealthy AHRS and fligh mode change failed warning problems were solved.I will inform you about the new situation after the open field driving tests.

1 Like