Automated Generation of Control Programs for Robotic Welding of Ship Structure (AUTOGEN)

The United States shipbuilding industry, like many other sectors of manufacturing, is confronted with reduced marketing opportunities coupled with international competitive pressures. To answer these challenges, the shipbuilding industry seeks more agile response to customer requirements, improved assurance of quality, and reduced manufacturing costs. The industry also must augment the dwindling supply of skilled welding craft personnel. These realities urge the use of robots to weld ship structure assemblages. Historically, this has proven an expensive and not always successful undertaking.

Description

AUTOGEN is the automatic planning of robotic welding using geometric part models and manufacturing intent. This software combines ship design information and manufacturing information to determine 1) what needs to be welded, 2) what weld joint types and sizes to use, and 3) the detailed plan for performing the welds. AUTOGEN is currently under development at Sandia’s Intelligent Systems and Robotics Center (ISRC) and promises to provide solutions to the shipbuilding industry.

Benefits

AUTOGEN software will automatically plan processes for robotic welding of ship component assemblies. This automation will provide several benefits. For instance:

• The labor of welding together ship panels accounts for a major portion of the cost of the ship; automation promises significant financial leverage.
  
• Current manual processes involve a high percentage of scrap, rework and process variation; automation promises precision and uniformity, producing a higher yield.
  
• Welding processes subject people to a variety of hazards including noxious fumes and molten metal; robotic automation can take people out of that hazardous environment.
  
• People-based processes have low effective arc-on time; robots potentially work without rest, around the clock.

Applications

AUTOGEN will provide the shipbuilding industry a flexible and economic solution for planning robotic welding of small lot assemblies of complex parts. In addition, the openness of AUTOGEN’s system should make it attractive in other related industries, such as railcar building and bridge fabrication. The system may also be applicable to other processes that require tool motion, such as laser welding, manipulating routers and deburring tools over large complex parts in the aircraft manufacturing industry, or delivering adhesives and similar fluids. In this way, it is expected that sufficient markets will be reached to sustain both continued development and commercial maintenance of the software.

AUTOGEN Development

ISRC’s development of AUTOGEN is divided into the following phases:

1. Abstract Ship Structure
   
2. Abstract Welding Task
   
3. Manipulator Kinematics and Dynamics
   
4. Automate Robot Joint Trajectories Design
   
5. Automatically Plan Individual Welds for a Single Robot
   
6. Demonstration, Summary Reports

Currently, researchers are working on phase 2 and 3 of the development process. The process has been smooth and on schedule. AUTOGEN has been tested using DIMS3, Pro/E, Catia, Tribon, and AutoCAD files from several shipyards. Performance of completed software modules exceeds design expectations and several technical breakthrough concepts have been discovered.