AUTOMATIC SUBASSEMBLY SEQUENCING FOR OFFSHORE RIGS

Abstract

THIS WORK EMPLOYS LEAN PRINCIPLES; THIS CAN BE SEEN IN THE REDUCTION OF WORK CONTENT , THE REDUCTION IN THE DOUBLE HANDLING OF PARTS AND IN REDUCING OR ELIMINATING WAITING TIME FOR SUBASSEMBLIES AT THE ASSEMBLY POINT. THIS WORK EMPLOYS POLYCHROMATIC SET THEORY AS ITS KNOWLEDGE BASE. USING THIS, PART CONNECTIVITY AND PART RELATIONSHIPS ARE IDENTIFIED. SUCH IDENTIFICATION ALLOWS FOR AN INFERENCE ENGINE TO AUTOMATICALLY IDENTIFY THE OPTIMAL CONSTRUCTION SEQUENCES OF THE SUBASSEMBLIES. AN OPTIMIZING ENGINE USES THE KNOWLEDGE FROM THE INFERENCE ENGINE TO COMBINE SUBASSEMBLIES INTO SUB-BLOCKS, IF POSSIBLE, WITHIN THE CONSTRAINTS OF LENGTH, WIDTH, HEIGHT AND WEIGHT OF THE SUB-BLOCK. THE OPTIMIZING ENGINE ALSO OPTIMIZES THE WELDING WORK SEQUENCE USING A GENETIC ALGORITHM IN SUCH A MANNER THAT THE WORK (SUBASSEMBLY &/OR SUB-BLOCK) ARRIVES AT THE REQUIRED ASSEMBLY POINT JUST-IN-TIME OR AS NEAR TO JUST-IN-TIME AS POSSIBLE.