Process Qualification for a Mobile Robotic Welding System Through Manipulability

Abstract

Advances in mobile robotics make these systems viable alternatives for developing new methods and techniques for manufacturing processes such as welding. When considering welding as a manufacturing process, the ability of the equipment to conduct the weld process must be verified. This step is called weld process validation and is generally conducted when a new machine or technique is introduced to the weld process. Traditionally, the weld validation process has focused on the electro-thermal aspects of the weld process, while the (human) welder qualification provides a certification step to ensure that an operator can perform the motion-control aspects of the weld operation while welding. The lack of industry standards for mechanized welding makes it difficult to introduce mobile robotic welding systems with validated performance in the market place. This paper will propose one approach to consider the motion control portion of the weld process validation for welding systems based on mobile robotic platforms. In particular, this paper will consider a skid-steer type mobile robot that is able to weld in flat, horizontal and vertical orientations. The paper will consider the motion-control portion of the weld validation process and will suggest a method that compares a mobile-robot-based welding process to a baseline (fixed-base track system) welding process through spanning manipulability ellipses. This approach allows general topologies of a mobile robotic welding system to be considered in a general way as a step to making mobile robotic welding a viable welding process.