Welding Robot Applications in Shipbuilding Industry: Off-Line Programming, Virtual Reality Simulation, and Open Architecture

The shipbuilding industry is steadily advancing by introducing robots to its work fields for increases in productivity and improvements in working conditions (Nagao et al, 2000). However, the shipbuilding company still faces with the worker’s health problem, an increase of aging workers, a shortage of skilled workers, and environmental protection related issues. Therefore, advanced robotic manipulator is still required to overcome these problems. And, how to apply commercial robotic system properly to meet the production purpose in the shipyard is a key research topic for shipbuilding engineers. The shipbuilding process is mainly divided into design, cutting, welding, assembling, grinding, blinding, and painting process. Among these manufacturing processes, welding is the most crucial, expensive, and time-consuming process. For that reason, welding robot applications have yielded a big productivity improvement in hull assembly welding and have reduced work-related musculoskeletal disorders of workers. In this chapter, the results of our work in the development of a welding robot system and a PC-based off-line programming for welding robot application on assembly lines in shipbuilding are explained. Also, a methodology of implementing PC-based off-line programming on users PC is presented. The off-line programming is a system that comprises robot’s simulation, robot programming, and other functions such as monitoring, scheduling, etc, that makes users operate robot system easily. The off-line programming is essential for welding robot system in shipyard to prepare robot program and then to shorten production time. Currently, the operation of industrial robots is through either on-line teaching or off-line programming (Choi & Lee, 2003; Carvalho et al., 1998; Craig, 1986;). On-line teaching is, by definition, a technique of generating robot programs using a real robot system, whereas offline programming is a method using simulations that are set up in advance. On-line teaching may be suitable for jobs for which a robot only needs to repeat a monotonous motion using one pre-written program that applies to identical sizes or objects. But, in such work places as shipbuilding, where the shape and size of workpiece are various (i.e., there are more than 1200 different shapes of workpieces for grand-assembly, if we account the size of these different shaped workpiece, we may not count the different kind of workpieces. Moreover, the new shape of workpiece is still increasing according to the ship specification