Universal Robots Forum

Delta (offset) implementation on pre-built coordinates

Hi all,

I have a set of pre-built movement of with all the coordinates based on the Datum point.

Is there anyway that the UR able to offset based on the delta, without touching my pre-built coordinate?
If yes, what is the function to be used?

Background:

Delta = New Input Point - Datum Point

.

Hello,

Assuming you have your Datum point already taught as a feature, you can do this easily. If you don’t yet have a feature defined, you’ll need to define it, then reteach your waypoints relative to the feature.

You can use the pose_trans() script function with a pose variable containing your offset to shift your feature. Position values for a pose must be in meters, and rotation values must be in radians. An example is below assuming you have named your feature “Datum”:

offset = p[0,0,0.50,0,0,0]
Datum = pose_trans(Datum, offset)

or

Datum = pose_trans(Datum, p[0,0,0.50,0,0,0])

This would result in Datum being shifted 50mm in the positive z-direction of the Datum feature. If you had a Move command relative to Datum, all the waypoints in that move would follow this shift.

Downloads for the most recent CB3 and e-series script manuals are below if you would like to read more about the pose_trans() and other motion script functions.

https://www.universal-robots.com/download/manuals-cb-series/script/script-manual-cb-series-sw3154/
https://www.universal-robots.com/download/manuals-e-series/script/script-manual-e-series-sw-511/

1 Like

Hi Miwa,

With this implementation, I received errors while running on the simulation. (Not all the point but some only)

It shows "The robot cannot reach the requested pose. Script function movej is unable to find an inverse kinematics solution"

Do you have any suggestion regards to this issue?

Am I correct to say the "offset applied " is out of the coverage by UR?