# 'joint\_wrist\_pitch' not valid joint name

**URL:** <https://forum.hello-robot.com/t/joint-wrist-pitch-not-valid-joint-name/953>\
**Category:** Ask\
**Created:** [April 12, 2024, 1:41am UTC](https://forum.hello-robot.com/t/joint-wrist-pitch-not-valid-joint-name/953 "2024-04-12T01:41:34Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![nwagwu](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.hello-robot.com/nwagwu/32/403_2.png) [@nwagwu](https://forum.hello-robot.com/u/nwagwu)\
**Post date:** [April 12, 2024, 1:41am UTC](https://forum.hello-robot.com/t/joint-wrist-pitch-not-valid-joint-name/953/1 "2024-04-12T01:41:34Z")

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Hi,

I had recently run into an issue where despite changing my tool in the params and in the URDF to the Dex Wrist V2, when I try to send commands to the pitch or roll they are not recognized as valid joints. I get the following error:

```auto
[INFO] [1712885094.998938]: /stretch_driver joint_traj action: New trajectory received with joint_names = ['joint_wrist_pitch']
[ERROR] [1712885095.003302]: /stretch_driver joint_traj action: Received a command without any valid joint names. Received joint names = ['joint_wrist_pitch']

```

I looked a bit deeper into the command groups code and saw that the following lines were both returning None in joint\_trajectory\_server.py.

```auto
module_name = self.node.robot.end_of_arm.params['devices'][joint].get('ros_py_module_name')
class_name = self.node.robot.end_of_arm.params['devices'][joint].get('ros_py_class_name')

```

I checked the dictionary entries and saw the ‘ros\_py\_module\_name’ and ‘ros\_py\_class\_name’ were were both missing and instead there was ‘py\_module\_name’ and ‘py\_class\_name’. Replacing the ‘ros’ ones with these alternatives entries the did not fix the issue however and spawned new errors.

I think someone may have mistakenly updated my Stretch ROS code and was wondering how I could go about resolving this issue. I tried looking back at previous commits to see if there was a point where ‘py\_module\_name’ was used in place of ‘ros\_py\_module\_name’ but hadn’t found where that had changed at all. I was wondering if I could get some guidance on fixing this issue.

Thanks

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<div class="post-metadata">

**Author:** ![nwagwu](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.hello-robot.com/nwagwu/32/403_2.png) [@nwagwu](https://forum.hello-robot.com/u/nwagwu)\
**Post date:** [April 22, 2024, 6:22pm UTC](https://forum.hello-robot.com/t/joint-wrist-pitch-not-valid-joint-name/953/2 "2024-04-22T18:22:39Z")

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This has been resolved. It appears it was a problem with the version of the python library I had been using for the Stretch RE 2.

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<div class="post-metadata">

**Author:** ![gonia](https://avatars.discourse-cdn.com/v4/letter/g/6de8d8/32.png) [@gonia](https://forum.hello-robot.com/u/gonia)\
**Post date:** [May 8, 2024, 4:59am UTC](https://forum.hello-robot.com/t/joint-wrist-pitch-not-valid-joint-name/953/3 "2024-05-08T04:59:19Z")

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Do you know which python library was causing the issue?