An Expert System Executive for Automated Assembly of Large Space Truss Structures

Langley Research Center developed a unique test bed for investigating the practical problems associated with the assembly of large space truss structures using robotic manipulators. The test bed is the result of an interdisciplinary e ort that encompasses the full spectrum of assembly problems|from the design of mechanisms to the development of software. This paper describes the automated structures assembly test bed and its operation, details the expert system executive and its development, and discusses the planned system evolution. Emphasis is on the expert system implementation of the program executive. The executive program must direct and reliably perform complex assembly tasks with the exibility to recover from realistic system errors. The employment of an expert system permits information that pertains to the operation of the system to be encapsulated concisely within a knowledge base. This consolidation substantially reduced code, increased exibility, eased software upgrades, and realized a savings in software maintenance