Concurrent object based modeling of fuzzy strategies

Rapid prototyping of complex systems and their control strategies is an important approach in system modeling, especially in early design stages. Naturally, these systems can be seen as a network of concurrently running communicating objects. A practical application field are flexible manufacturing systems (FMS) used in computer integrated manufacturing (CIM). An FMS consists of concurrently working machines which are connected by a computerized material handling system. This leads to well-known problems like scheduling and resource allocation where the usefulness of the fuzzy logic approach has been shown. Concurrent objects as a modeling paradigm enable the designer to describe the system's structure and behavior naturally on a high abstraction level. In this paper we argue that the control strategies based on complex hierarchical fuzzy rule bases fit nicely in the concurrent object based modeling view and, consequently, in a consistent design approach. Moreover, we introduce a suitable programming language (DFKI Oz), extended by a fuzzy library, which supports the described modeling approach. Validation of our approach is described by modeling a complex FMS in the field of car production.