Universal Robots Forum

Plane Feature creation with offset Origin

I would like to be able to create a plane feature, but have the origin located at the intersection of two lines. For example, The workpiece is a rectangular block with a radius on the front left corner. The desired origin for the workpiece is shown on the drawing as a point in space, defined by a line along the top left edge intersecting with a line along the top front edge. In other words, the origin is at the point where the front left corner would be if it did not have a radius.

The end effector I am using has the ability to establish points anywhere on the top surface, or along the edges defined by the intersection of the top surface and the vertical sides.

The question I have is how can I create a Plane feature with the origin in the correct location? The only way I know of creating a plane feature results in the first point taken on the top surface defining the feature origin. Ideally, I would like to capture two points on the left edge and define a line through them. Then do the same on the front edge and intersect the two lines to create the origin point.

Does anyone know how this can be achieved?

I’m pretty terrible at visualizing things, but can I ask WHY you need the origin in a specific location? Typically the origin is just some arbitrary point, as it’s just used to establish a reference frame. Any moves taught against a Feature will behave the same way regardless of where that origin actually was. As long as it is consistently taught, you’d be able to move your workpiece wherever, re-teach your 3 feature points, and you’re ready to roll. The point, as I understand it, is to make the 3 Feature points easy to reach and let the robot do all the heavy lifting math to get the correct offsetting.

I understand the importance of having the origin of your plane in the correct position.
you may need to move to a measured point along one of the axis for example,
or if you have differing size parts with the same centre point.
there are many reasons why it can be crucial.

For me the best way to achieve this it to teach the plane on the part somewhere accessible using one of the edges (eg x) make sure the y axis is parallel to the intersecting y line. Once the plane is taught measure form your origin point or along the y plane back to where your y should be.

Now edit the plane and select the feature you have just made it will display as x 0, y 0, z 0 etc now manually write the value of y to the measured value (Remember it my be a negative value) .
confirm the new position.
now move to the plane position and the robot should now be at your correct origin position.

Good question! The main reason why I want to set the origin in an exact location is so I can position the TCP at exact locations on the workpiece relative to the origin specified in the CAD model. The robot is carrying a non-contact measurement device that will be used for dimensional inspection and process control purposes. For example; The model specifies that an edge profile measurement must be taken at precise location relative to the origin defined in the model. It would be near impossible to manually teach this position at anything like the required accuracy, but if the feature origin corresponds with the origin in the model, I can simply specify the X, Y, and Z coordinates from the model and be sure that the measurement will be taken in the correct place.

Brilliant! Thank you. It sounds rather obvious when you explain it like that, slightly embarrassed that I hadn’t figured that out for myself! I’ll fire up the sim shortly and give it a try. Many thanks. :smiley:

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