The robot is failing to detect the lift motor

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1

Hello everyone! I’m running into an issue where the robot’s lift motor has suddenly stopped being detected by the system. The OS boots normally and all the other motors appear under their usual /dev/ttyACM* device paths, but the lift motor is completely missing, which prevents the robot from entering gamepad/teleop mode. Since this happened abruptly, I’m not sure whether this is a firmware issue, a USB enumeration problem, or a hardware fault on the stepper board. Has anyone encountered this before or have suggestions for next steps?

Here some of my logs:

hello-robot@stretch-se3-3122:~$ stretch_lift_home.py
For use with S T R E T C H (R) from Hello Robot Inc.
---------------------------------------------------------------------

[ERROR] [hello-motor-lift]: SerialException(2): could not open port /dev/hello-motor-lift: [Errno 2] No such file or directory: '/dev/hello-motor-lift'
[WARNING] [hello-motor-lift]: Unable to open serial port for device /dev/hello-motor-lift


hello-robot@stretch-se3-3122:~$ stretch_system_check.py
For use with S T R E T C H (R) from Hello Robot Inc.
---------------------------------------------------------------------

Model = Stretch 3
Tool = DexWrist 3 w/ Gripper
Serial Number = stretch-se3-3122

[ERROR] [hello-motor-lift]: SerialException(2): could not open port /dev/hello-motor-lift: [Errno 2] No such file or directory: '/dev/hello-motor-lift'
[WARNING] [hello-motor-lift]: Unable to open serial port for device /dev/hello-motor-lift
[WARNING] [robot]: Not able to use asyncio for transport communications. Defaulting to sync.


hello-robot@stretch-se3-3122:~$ ls /dev/hello-*
/dev/hello-dynamixel-head     /dev/hello-motor-left-wheel   /dev/hello-respeaker
/dev/hello-dynamixel-wrist    /dev/hello-motor-right-wheel  /dev/hello-wacc
/dev/hello-lrf                /dev/hello-nav-head-camera
/dev/hello-motor-arm          /dev/hello-pimu
hello-robot@stretch-se3-3122:~$
2

Hi @gabxap ,

Thank you for your post and your debugging information.

It’s not immediately clear what the issue is. Could you please collect more info about your system and send it to us? You can post it here or email support@hello-robot.com.

  1. Start by power cycling the robot.
  2. Run sudo dmesg and post the output here (it will be long).
  3. Run ls -al /dev/ttyACM* and post the output here.
  4. Run REx_firmware_flash.py --map and post the output here.
  5. Run REx_discover_hello_devices.py --list and post the output here.
  6. Run cat /etc/udev/rules.d/95-hello-arduino.rules and post the output here.
  7. Run cat /etc/udev/rules.d/99-hello-dynamixel.rules and post the output here.

Best,
Shehab

3

Hi, thank you very much for your support. The issue resolved itself. If the problem reappears, I will reach out to you.

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