Persistent PX4 Sensor/Accel Failure on Stinger (D0013) with SDK 1.6.2 + Dev IMU/OV Servers

[YUUJI INOUE]

Support Request: Persistent PX4 Sensor/Accel Failure on Stinger (D0013) with SDK 1.6.2 + Dev IMU/OV Servers

System Information

• Hardware: ModalAI Stinger (D0013)
• Base SDK Version: SDK 1.6.2 (Clean install performed recently)
• Updated Packages:
  • qrb5165-imu-server: Built from dev branch (to support body frame output)
  • voxl-open-vins-server: Built from dev branch
• Camera Configuration: Tracking Cameras (Front/Down) only.

Current Status

After a clean install of SDK 1.6.2 and upgrading the IMU and OpenVINS servers to the dev branch versions (as suggested to handle D0013's inverted IMU natively):

1. VIO Tracking: Success. The drone is tracking perfectly in the Web Portal's 3D view. The virtual drone follows the real drone's movements correctly (RPY and translation).
2. VOXL Vision Hub: Success. voxl-vision-hub reports result: true in the Web Portal system check.
3. Image Sensors: Success. Previously reported errors, but now imageSensor0 and imageSensor1 are detected correctly.
4. PX4 Flight Controller: FAILURE.
   • voxl-px4 reports result: false in the Web Portal system check.
   • Specific Error: sensor_accel: result false (e.g., x: -0.28, y: -0.28, z: 9.63).
   • The drone cannot enter Position Flight Mode.
   • QGroundControl allows Arming in Manual mode, but rejects Position mode.

Steps Taken

1. Clean Install: Re-flashed SDK 1.6.2 to ensure a clean state.
2. Custom Build: Built and installed qrb5165-imu-server and voxl-open-vins-server from their dev branches on the device (using voxl-cross docker).
   • This resolved previous issues with "Upside Down" initialization and VIO coordinate frame mismatches.
3. Calibration: Performed clean IMU and Camera calibrations via voxl-configure-mpa and QGroundControl.
4. Verification: Checked Web Portal. VIO is healthy, but PX4 fails to initialize the accelerometer properly.

Logs & Errors

We have attached the full voxl-px4.log, voxl-imu-server.log, and voxl-vision-hub.log files. Below are the critical errors observed.

1. Parameter File Access Error (from voxl-px4.log)

PX4 fails to access the parameter file, which may be causing it to load incorrect defaults.

Dec 19 09:35:49 m0104 voxl-px4[3893]: INFO  [param] selected parameter default file /data/px4/param/parameters
Dec 19 09:35:49 m0104 voxl-px4[3893]: ERROR [param] open '/data/px4/param/parameters' failed (2)

2. Sensor Start Timeouts (from voxl-px4.log)

The system attempts to start the IMU driver (icm42688p) but times out.

Dec 19 09:35:49 m0104 voxl-px4[3893]: Starting IMU driver with rotation 12
Dec 19 09:36:09 m0104 voxl-px4[3893]: INFO  [qshell] Send cmd: 'icm42688p start -s -R 12'
Dec 19 09:36:09 m0104 voxl-px4[3893]: ERROR [qshell] command timed out
Dec 19 09:36:09 m0104 voxl-px4[3893]: ERROR [qshell] Command failed

3. Accelerometer Failure (from voxl-px4.log)

This is the direct cause of the sensor_accel: result false status.

Dec 19 09:36:49 m0104 voxl-px4[2171]: ERROR [muorb] [sensors] Accel #0 fail:  TIMEOUT!

4. IMU Server Analysis (from voxl-imu-server.log)

The voxl-imu-server appears to be running and detecting the IMU correctly (Detected M0104 VOXL2 mini, detected ICM42688).
It loads calibration data successfully.

Dec 19 10:13:42 m0104 voxl-imu-server[30843]: detected ICM42688 on spi bus[id] 3
Dec 19 10:13:42 m0104 voxl-imu-server[30843]: started fifo on imu0

IMU server seems healthy and publishing data.

5. Vision Hub Analysis (from voxl-vision-hub.log)

voxl-vision-hub successfully connects to the VIO pipe (ov), but reports an issue with finding a specific extrinsic relation.

Dec 19 10:07:19 m0104 voxl-vision-hub[1723]: Connected to VIO pipe: ov
Dec 19 10:07:19 m0104 voxl-vision-hub[1723]: Geometry module updating to use imu: imu_apps_body for VIO
...
Dec 19 10:07:17 m0104 voxl-vision-hub[1723]: ERROR: /etc/modalai/extrinsics.conf missing body to imu_apps_body, sticking with identity for now

Also, there are connection errors to voxl-mavlink-server:

Dec 19 10:07:19 m0104 voxl-vision-hub[1723]: Error trying to send control command to pipe ch4 /run/mpa/mavlink_onboard/, not connected

This suggests that while VIO itself is running, the communication chain to send this data to PX4 (via mavlink-server) might be broken or misconfigured.

Questions

Despite VIO working perfectly with the updated servers and voxl-imu-server appearing healthy, PX4 consistently fails to validate the accelerometer (sensor_accel: result false).

1. Is there a specific PX4 parameter or driver configuration in SDK 1.6.2 that conflicts with the Stinger (D0013) hardware, even with the updated IMU server?
2. The accelerometer values (z ~ 9.6) seem physically reasonable for a stationary drone. Why does the check return false?
3. Are there known compatibility issues with voxl-px4 and the dev branch qrb5165-imu-server?

voxl-vision-hub.log
voxl-imu-server.log
voxl-px4.log

[Eric Katzfey]

@YUUJI-INOUE Can you send a PX4 log? If you can arm in manual mode then the PX4 IMU is working fine. The last voxl-px4 message sequence shows the IMU start correctly. If the parameters file does not yet exist (e.g. no PX4 parameters have been updated yet) then there will be no /data/px4/param/parameters file and you will see the error message: "open '/data/px4/param/parameters' failed". That is fine and to be expected. Once you have updated some parameters (e.g. running voxl-px4-param) then that file will be created and that error message will no longer appear.