Hitachi Zosen Corporation Ariake Works has suc ceeded in the development of a unique NC painting robot for shipbuilding, which has been developed aiming at the realization of automatic painting in the water ballast tank of closed double hull blocks, and started to apply it in the production of VLCC.
1. Application Concept：
In the case of Ariake Works, the double hull block of VLCC is gland assembled as a huge cubic block with 20m length, 30m width, 8 m height, and weight approx. 650 tons. In order to automate the painting activity of closed tank of such huge block, a unique application concept of painting robot with following features was devised： (1) Use of self-driving type portable NC robots which enable them to run on the Face Plate of Longitudinal Frames without rail. (2) Each floor shall have a permanent opening for passing through of robot in the structural design. (3) High adaptability for current ship production system since plural robots are optionally applicable to the block anywhere. (4) Investment scale of facility is very small, and nearly 100% robot painting is geometrically possible for the inside tank of closed double hull block. (5) Operation linkage between CAD/CAM and robot systems is possible in the ship-yard CIM environment.
Figure 1 shows the necessary consideration on the structural design of ship. Using the structural analysis program of classification society, the optimum location of permanent opening for the Floor and/or the suitable stiffening method are discussed and reflected into the structural design of ship.
2. Hardware：
The hardware is composed by a robot main body, a controller and an automatic painting unit. The robot main body is very compact and mounts a manipulator with 6 axes and a placer with external axes on a self-driving type carriage. And it runs on the Faces of two Longitudinal Frames without rails by utilizing two sets of magnetic crawlers passing through a permanent opening preliminary prepared into the Floors.
A PC-based controller has been developed, whose CPU is Intel Pentium 150 MHz, OS is Windows NT, and it uses an object oriented control method considering the performances of high speed processing and possibility of extension.
Two liquids mixture type paint (Tar-Epoxy) is used for the Water Ballast Tank of double hull.
