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):

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).
VOXL Vision Hub: Success. voxl-vision-hub reports result: true in the Web Portal system check.
Image Sensors: Success. Previously reported errors, but now imageSensor0 and imageSensor1 are detected correctly.
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

Clean Install: Re-flashed SDK 1.6.2 to ensure a clean state.
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.
Calibration: Performed clean IMU and Camera calibrations via voxl-configure-mpa and QGroundControl.
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).

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?
The accelerometer values (z ~ 9.6) seem physically reasonable for a stationary drone. Why does the check return false?
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.

YUUJI INOUE

@Eric-Katzfey

Updated Support Request: Parameter Fix Attempt & Remaining Accelerometer/Position Mode Issues

Following the advice to update parameters, we have made progress but still cannot enter Position Mode due to persistent sensor checks failures.

Actions Taken

Parameter Reset & Load:
- Executed voxl-configure-px4-params --wizard and selected D0013 (Stinger).
- Confirmed that /data/px4/param/parameters is now created and populated.
Battery Configuration Fix:
- Manually corrected BAT_N_CELLS to 4 (was defaulting to 6) and BAT_LOW_VOLT to 14.0V.
- This successfully resolved the "Low Voltage" warning in QGC.
Re-Calibration:
- Performed fresh Accelerometer, Level Horizon, and Compass calibrations in QGC.
- Performed Camera calibration.

Current Status

Manual Mode: OK. We can Arm the drone and spin motors in Manual Mode. We have also performed a successful test flight in Manual Mode.
VIO: OK. The virtual drone in Web Portal follows the real drone perfectly.
Position Mode: FAILED.
- QGC shows "Ready for flight" briefly after reboot, but rejects Arming (Command denied).
- After disarming from a Manual Mode test, Position Mode switches to "Not Ready".
Web Portal System Check: FAILED.
- voxl-px4 still reports sensor_accel: result false.
- Values (e.g., z: 9.70) seem correct, but the check fails.

Persistent Logs Errors (New Logs Attached)

Despite the parameter fix, voxl-px4.log still shows communication timeouts with the sensors:

ERROR [muorb] [sensors] Accel #0 fail: TIMEOUT!
ERROR [qshell] Command failed
ERROR [muorb] [drivers__device] i2c probe failed

Questions

Since we can Arm in Manual Mode (suggesting the IMU hardware is working) and have loaded the correct D0013 parameters, why does voxl-px4 still report sensor_accel: result false with timeouts?
Is there a specific driver or timing parameter in SDK 1.6.2 (with the dev branch IMU server) that causes these spurious timeouts on the Stinger?
What is preventing Position Mode Arming even when VIO is healthy and Manual Arming works?

We have attached the latest logs (voxl-px4.log, voxl-vision-hub.log) from this new configuration state.
voxl-px4.log
voxl-vision-hub.log

YUUJI INOUE

@YUUJI-INOUE said in Persistent PX4 Sensor/Accel Failure on Stinger (D0013) with SDK 1.6.2 + Dev IMU/OV Servers:

@Eric-Katzfey

Updated Support Request: Parameter Fix Attempt & Remaining Accelerometer/Position Mode Issues

Following the advice to update parameters, we have made progress but still cannot enter Position Mode due to persistent sensor checks failures.

Actions Taken

Parameter Reset & Load:

Executed voxl-configure-px4-params --wizard and selected D0013 (Stinger).

Confirmed that /data/px4/param/parameters is now created and populated.

Battery Configuration Fix:

Manually corrected BAT_N_CELLS to 4 (was defaulting to 6) and BAT_LOW_VOLT to 14.0V.

This successfully resolved the "Low Voltage" warning in QGC.

Re-Calibration:

Performed fresh Accelerometer, Level Horizon, and Compass calibrations in QGC.

Performed Camera calibration.

Current Status

Manual Mode: OK. We can Arm the drone and spin motors in Manual Mode. We have also performed a successful test flight in Manual Mode.

VIO: OK. The virtual drone in Web Portal follows the real drone perfectly.

Position Mode: FAILED.

QGC shows "Ready for flight" briefly after reboot, but rejects Arming (Command denied).

After disarming from a Manual Mode test, Position Mode switches to "Not Ready".

Web Portal System Check: FAILED.

voxl-px4 still reports sensor_accel: result false.

Values (e.g., z: 9.70) seem correct, but the check fails.

Persistent Logs Errors (New Logs Attached)

Despite the parameter fix, voxl-px4.log still shows communication timeouts with the sensors:
ERROR [muorb] [sensors] Accel #0 fail: TIMEOUT!
ERROR [qshell] Command failed
ERROR [muorb] [drivers__device] i2c probe failed
Questions

Since we can Arm in Manual Mode (suggesting the IMU hardware is working) and have loaded the correct D0013 parameters, why does voxl-px4 still report sensor_accel: result false with timeouts?

Is there a specific driver or timing parameter in SDK 1.6.2 (with the dev branch IMU server) that causes these spurious timeouts on the Stinger?

What is preventing Position Mode Arming even when VIO is healthy and Manual Arming works?

We have attached the latest logs (voxl-px4.log, voxl-vision-hub.log) from this new configuration state.
voxl-px4.log
voxl-vision-hub.log

I've been hooked on this for two weeks now. Can someone tell me how to set up STINGER VER1 from scratch?