# Rotation Speed in speedl()

**URL:** <https://forum.universal-robots.com/t/rotation-speed-in-speedl/28845>\
**Category:** Technical Questions\
**Created:** [June 6, 2023, 9:52am UTC](https://forum.universal-robots.com/t/rotation-speed-in-speedl/28845 "2023-06-06T09:52:09Z")\
**Posts on this page:** 1\
**Showing post:** 1

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**Author:** ![eehwee.lim](https://avatars.discourse-cdn.com/v4/letter/e/2bfe46/32.png) [@eehwee.lim](https://forum.universal-robots.com/u/eehwee.lim)\
**Post date:** [June 6, 2023, 9:52am UTC](https://forum.universal-robots.com/t/rotation-speed-in-speedl/28845/1 "2023-06-06T09:52:09Z")

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Dear all,

Would like to clarify about the rotational speed in speedl() of URScript:

1. The rotational speed Rx, Ry, and Rz are expressed in terms of rotation vector or RPY angular velocity?

2. The rotation is wrt. the robot base frame or tool frame?

I have been using rotation vector wrt. robot base frame when trying to control the orientation of the TCP, but the behaviour is unexpected and can’t be explained. I think my assumptions above could be wrong, hence the clarification.

Thank you!  
Jeff

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