Rotation Speed in speedl()

Technical Questions
1

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

1 Like
3

do you have solved the problem?i also meet the same problem and don’t konw the meaning of rotation speed.

4

Did you get any updates on this? I’d be interested in the same question.

5

Hi,

It is Rotation vector and in Base frame. I did a test in URSim, as below:

#1. create a program using speedl: speedl([0,0,0,0.5,0.5,0.5],0.2)
#2. run the program and use UR Log Viewer to log the tcp speed. from the rx ry rz speed is accelerated to 0.5

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there is still a question, how to calculate the final position of the speedl, I will try to do the math and update later.

6

for the rotate acceleration in speedl, it shall be the angle acceleration in axis-angle expression,

the rotation vector used in UR system can be normalized to a direction vector and a rotation angle, in the example above, the rotate angle speed is 0.866, and the acceleration is 0.2, so the time shall be 4.33s.

when the function returns, the timer is 4.53.

maybe I am wrong…

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