Stretch2 Robot Arm PCB Issue: Gripper and Wrist Motors Not Detected

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1

Hi,

I am using Stretch 2 for a project.
I got the following error msg while performing stretch_gripper_home.py, I got the following error msg.

hello-robot@stretch-re2-2068:~$ stretch_robot_home.py 
For use with S T R E T C H (R) RESEARCH EDITION from Hello Robot Inc.
---------------------------------------------------------------------

[WARNING] [stretch_gripper]: DynamixelHelloXL430 Ping failed... stretch_gripper
DynamixelHelloXL430 Ping failed... stretch_gripper
[WARNING] [robot]: Not able to use asyncio for transport communications. Defaulting to sync.
--------- Homing Head ----
--------- Homing Lift ----
Homing Lift...
Hardstop detected at motor position (rad) 99.39265441894531
Marking Lift position to 1.100000 (m)
Marking Lift position to 0.000000 (m)
[INFO] [robot_monitor]: Guarded contact lift
[INFO] [robot_monitor]: Wrist single tap: 33
[INFO] [robot_monitor]: Base bump event
[INFO] [robot_monitor]: Wrist single tap: 34
[INFO] [robot_monitor]: Base bump event
[INFO] [robot_monitor]: Base bump event
Lift homing successful
--------- Homing Arm ----
Homing Arm...
[INFO] [robot_monitor]: Wrist single tap: 35
Hardstop detected at motor position (rad) -7.261442184448242
Marking Arm position to 0.000000 (m)
[INFO] [robot_monitor]: Guarded contact arm
[INFO] [robot_monitor]: Wrist single tap: 37
[INFO] [robot_monitor]: Wrist single tap: 38
Arm homing successful
[WARNING] [stretch_gripper]: Not able to home stretch_gripper. Hardware not present
[WARNING] [wrist_yaw]: Not able to home wrist_yaw. Hardware not present

And when I use this command, “REx_dynamixel_id_scan.py /dev/hello-dynamixel-wrist”, I got the following error msg:

hello-robot@stretch-re2-2068:~$ REx_dynamixel_id_scan.py /dev/hello-dynamixel-wrist
For use with S T R E T C H (R) RESEARCH EDITION from Hello Robot Inc.
---------------------------------------------------------------------

Scanning bus /dev/hello-dynamixel-wrist
Checking ID 0
Checking ID 1
Checking ID 2
Checking ID 3
Checking ID 4
Checking ID 5
Checking ID 6
Checking ID 7
Checking ID 8
Checking ID 9
Checking ID 10
Checking ID 11
Checking ID 12
Checking ID 13
Checking ID 14
Checking ID 15
Checking ID 16
Checking ID 17
Checking ID 18
Checking ID 19
Checking ID 20
Checking ID 21
Checking ID 22
Checking ID 23
Checking ID 24
Found 0  servos on bus /dev/hello-dynamixel-wrist

I beilieve there might be some software or hardware issues, could you please help suggest ways to solve this?

2

Stretch2 Robot Arm PCB Issue: Gripper and Wrist Motors Not Detected

Description

We’re experiencing issues with our Stretch2 robot, specifically with the gripper and wrist motors not being detected. We suspect a problem with the PCB in the robot’s arm.

Steps to Reproduce

  1. Run stretch_robot_home.py
  2. Run stretch_robot_dynamixel_reboot.py
  3. Directly connect gripper yaw motor to USB using U2D2 adapter

Observed Behavior

When running stretch_robot_home.py:

hello-robot@stretch-re2-2068:~$ stretch_robot_home.py
For use with S T R E T C H (R) RESEARCH EDITION from Hello Robot Inc.
---------------------------------------------------------------------

[WARNING] [stretch_gripper]: DynamixelHelloXL430 Ping failed... stretch_gripper
DynamixelHelloXL430 Ping failed... stretch_gripper
[WARNING] [robot]: Not able to use asyncio for transport communications. Defaulting to sync.
--------- Homing Head ----
--------- Homing Lift ----
Homing Lift...
Hardstop detected at motor position (rad) 99.39265441894531
Marking Lift position to 1.100000 (m)
Marking Lift position to 0.000000 (m)
[INFO] [robot_monitor]: Guarded contact lift
[INFO] [robot_monitor]: Wrist single tap: 33
[INFO] [robot_monitor]: Base bump event
[INFO] [robot_monitor]: Wrist single tap: 34
[INFO] [robot_monitor]: Base bump event
[INFO] [robot_monitor]: Base bump event
Lift homing successful
--------- Homing Arm ----
Homing Arm...
[INFO] [robot_monitor]: Wrist single tap: 35
Hardstop detected at motor position (rad) -7.261442184448242
Marking Arm position to 0.000000 (m)
[INFO] [robot_monitor]: Guarded contact arm
[INFO] [robot_monitor]: Wrist single tap: 37
[INFO] [robot_monitor]: Wrist single tap: 38
Arm homing successful
[WARNING] [stretch_gripper]: Not able to home stretch_gripper. Hardware not present
[WARNING] [wrist_yaw]: Not able to home wrist_yaw. Hardware not present

When running stretch_robot_dynamixel_reboot.py:

hello-robot@stretch-re2-2068:~$ stretch_robot_dynamixel_reboot.py
For use with S T R E T C H (R) RESEARCH EDITION from Hello Robot Inc.
---------------------------------------------------------------------

[WARNING] [stretch_gripper]: DynamixelHelloXL430 Ping failed... stretch_gripper
DynamixelHelloXL430 Ping failed... stretch_gripper
[WARNING] [robot]: Not able to use asyncio for transport communications. Defaulting to sync.
Rebooting: head_pan
[Dynamixel ID:011] Reboot Succeeded.
Rebooting: head_tilt
[Dynamixel ID:012] Reboot Succeeded.

Direct connection test:

When bypassing the arm’s PCB and connecting the gripper yaw motor directly to USB via U2D2, an ID scan successfully detected all four Dynamixel motors (yaw, roll, pitch, and gripper).

Screenshot 2024-09-30 at 6.03.42 PM
Screenshot 2024-09-30 at 6.03.42 PM982×854 75.2 KB

Expected Behavior

The gripper and wrist motors should be detected and functional when connected through the arm’s PCB.

Additional Context

Based on our tests, we believe the PCB in the robot’s arm may be malfunctioning.

Questions

  1. Can you confirm if our diagnosis of a faulty PCB in the arm is correct?
  2. If so, is there a way to repair this PCB?
  3. Alternatively, how can we obtain a replacement PCB for the Stretch2 robot arm?

We appreciate any guidance on resolving this issue to restore full functionality to our Stretch2 robot. Thank you!

4

Hi @seung, it looks like you’ve done all the correct debugging steps needed to isolate the problem

If you can email support@hello-robot.com with your name, phone number, and best suitable address that we can send you a replacement PCB that would be great

-Visaacan