HOLONIC FAULT-TOLERANT CONTROL OF NETWORKED ROBOT-VISION ASSEMBLY STATIONS

The paper describes a networked fault-tolerant assembly system of job shop type containing multiple robotized stations operating under visual control. During the assembly process, the products are identified, located, qualified, and controlled by analyzing images from virtual cameras associated to stationary- and arm-mounted cameras. The holonic control architecture is formed by the following types of entities: a Global Assembly Scheduler generating Order Holons, a dual layer of Material Handling (Robot) Holons and Sensory Holons, and a System Monitoring & Database entity. These elements are embedded in a 3-layer computing & control structure, and interconnected by a 4-fold fault-tolerant communication network keeping track of assembly job execution. Implementing issues and experimental results are reported.