Universal Robots

This page is a guide to help users understand the requirements of setting up a Universal Robots robotic welding system for use with Verbotics Weld. Verbotics also offer consulting and training services to assist with the calibration and setup of a welding system - please contact us for pricing.

TCP Calibration

The real world TCP should be calibrated using the Universal Robots calibration tool. After calibration, it is then suggested that the rotational values are overwritten with theoretical values (that can be supplied by Verbotics) as rotational values are difficult to calibrate using this method.

Care should be taken to ensure that the the Z axis of the tool is pointing outwards along the wire direction.

The TCP calibration should use the expected stick-out specified in the workcell model file supplied by Verbotics for the cell. If used, the wire cut routine should be written to cut the wire to this length and will be called by Verbotics prior to wire touch sensing.

Sensing

Typically we use nozzle-based force sensing for Universal Robots, which is available for e-Series and newer. We can also integrate with wire touch and 1D laser sensors if this can be controlled from URScript.

Welder and Ancillary Integration (URCap)

Verbotics Weld generates native Universal Robot Program (.urp) program files to load into your robot, using standard graphical UR Move, Script and other commands.

To interface with your welding power source, wire cut routines, and any external axes or other ancillary equipment, you will load a simple Verbotics URCap onto your robot. A URScript configuration will be loaded, with functions which will need to be implemented to interact with your specific welding power source and robot setup. Please note we will not typically generate customised URCap nodes which may be provided by your welding power source provider’s URCap implementation.

The functions that will need to be implemented are:

  • vb_arc_on and vb_arc_off - start and stop welding

  • vb_set_weld_settings(program id, speed, voltage, current, wire feed) - configure the weld schedule or parameters.

If a torch clean and/or wire cut module are present:

  • vb_cut_wire

  • vb_clean_torch

  • vb_get_touch_sense_detected and vb_set_touch_sense_active if wire touch sensing is used.

These functions can be populated if required for your specific workcell:

  • vb_before_run and vb_after_run

  • vb_at_home

  • vb_before_sense and vb_after_sense - typically used to retract the wire before nozzle touch sensing.

  • Additional routines to support dynamic weld skipping (if desired).

  • vb_before_weld and vb_after_weld

  • vb_move_workpiece_positioner and vb_move_robot_positioner if you have external axes.