A computer-aided monitoring strategy for flexible assembly operations
is presented. This strategy uses knowledge-based expert systems for er
ror detection and diagnosis. The hierarchy of the system is embedded i
n a blackboard control structure to facilitate parallel, asynchronous
communication and to enhance the flexibility of the system. The develo
ped detection and diagnosis modules of the system were validated exper
imentally on a prototype robotic assembly work cell. The investigation
demonstrated the uniqueness of the new system through the elimination
of error propagation and the need for event backtracking if an enviro
nment change occurs. (C) 1997 Elsevier Science B.V.