le_classmate_ros

ROS Interface for Laser and Arc Welding on Lincoln Electric Classmate Cells

This package provides a ROS-compatible control layer for a Fanuc-driven Lincoln Electric Classmate welding cell. It enables service-based control of welding operations via comet_rpc, conversion of CAD geometries into robot trajectories, and execution of coordinated laser or arc weld paths.

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Features

• ROS service interface for laser and arc welding control
• DXF-based trajectory generation for weld paths
• Integration with comet_rpc for direct I/O-level control of Fanuc systems
• Custom weld macros support via LS files
• Launch file and service definitions for easy orchestration
• Standalone API for non-ROS workflows via the Welder class

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Directory Structure

le_classmate_ros/
├── CMakeLists.txt
├── package.xml
├── launch/
│   └── welder.launch                  # Launches the welder service node
├── scripts/
│   ├── dxf_script.py                  # Converts DXF to Cartesian poses and executes them
│   ├── test_script.py                 # Basic test for arc welding I/O
│   └── laser_run.py                   # ROS node providing weld + laser services
├── srv/
│   ├── Weld.srv                       # Service: Start/Stop welding
│   ├── LaserArm.srv                   # Service: Arm/Disarm laser
│   └── LaserEmit.srv                  # Service: Start/Stop laser emission
├── data/
│   └── rect2.dxf                      # Example DXF path input
├── ls/
│   └── ros_movesm.ls                  # Fanuc LS macro for ROS motion
├── src/
│   └── le_classmate_ros/
│       └── Welding.py                 # Core welder class wrapping comet_rpc I/O

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Dependencies

ROS Packages

• rospy
• roscpp
• geometry_msgs
• fc_msgs
• fc_tasks

Python Packages

• comet_rpc (https://github.com/gavanderhoorn/comet_rpc)
• ezdxf
• numpy

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Services

Provided by laser_run.py node:

Service Name	Type	Description
/weld_start	Weld.srv	Start arc welding process
/weld_end	Weld.srv	End arc welding process
/laser_arm	LaserArm.srv	Prepare laser for emission
/laser_disarm	LaserArm.srv	Disable laser safely
/laser_emit_start	LaserEmit.srv	Begin laser emission
/laser_emit_stop	LaserEmit.srv	Stop laser emission

All services return a bool State field indicating success.

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Installation

1. Install the fanuc_ros1 repository in a docker container.
2. Replicate the rosmovesm.ls (found in the ls/ directory) changes in your robot controller teach pendant .
3. Clone le_classmate_ros into the src folder.

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Usage

1. Build

cd ~/ros1_ws
catkin build
source devel/setup.bash

2. Launch Welder Node

roslaunch le_classmate_ros welder.launch

This launches laser_run.py, which exposes service interfaces for welding.

3. DXF Trajectory Execution

rosrun le_classmate_ros dxf_script.py

Reads .dxf, transforms geometry to robot coordinates, and sends it to the controller via fc_execute_cartesian_trajectory.

4. Layered Test

rosrun le_classmate_ros layered_test.py

Runs a two layered line laser weld in a sequence.

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Using the Welder Class Without ROS

The Welding.Welder class can be used directly in standalone Python scripts to control welding I/O over RPC:

from le_classmate_ros.Welding import Welder
import comet_rpc as rpc

with rpc.Server('192.168.2.151') as server:
    welder = Welder(server,
                    laser_power_watts=800)

    # Prepare and start laser
    welder.laser_ready_arm()
    welder.laser_start_emit()

    # Move robot using your control stack...

    # Stop laser and disarm
    welder.laser_stop_emit()
    welder.laser_disarm()

    # Start arc weld
    welder.weld_start()
    # Wait for motion...
    welder.weld_end()

The class handles all relevant I/O mappings and safety interlocks. An example is shown in scripts/welder_class_example.py

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I/O Mapping Summary

Type	Index	Function
DOUT	25	Weld Start
DOUT	26	Gas Start
DIN	25	Arc Detect
DIN	27	Gas Fault
DIN	28	Wire Fault
AOUT	1–6	Weld Cmds (voltage, etc.)
AIN	1–4	Weld Feedback
DOUT	20	ArcTool Weld Start
DOUT	21	ArcTool Weld End

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Author

Ankit Aggarwal
[email protected]
Carnegie Mellon University | Manufacturing Futures Institute

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