Reconfigurable Embedded Systems: a Systematic Design Tools & Architecture |
Embedded systems are playing an increasingly important role in controlengineering. Despite their popularity, embedded systems are generally subjectto resource constraints and it is therefore difficult to build complex controlsystems on embedded platforms. This approach is therefore based on the IEC 61499reference model for distributed and reconfigurable automation and uses theservice interface function block concept and high level communication patternsto achieve a hardware-independent access to communication services. Digital Control System in the industry hasbeen used in most of the applications based on expensive Programmable LogicalControllers (PLC). These Systems are, in general, highly complex and slow, withan operation cycle around 10ms. In this work, a Reconfigurable Logic Controller(RLC) approach is presented based on a small and low cost Xilinx Virtex-II FPGAarchitecture, operating as a virtual hardware machine. ReconfigurableManufacturing Systems hold promise to satisfy the requirements of dynamic andcompetitive modern manufacturing. Holonic control architecture is often usedfor the control of such reconfigurable systems. In this research, softwareagents and IEC 61499 function blocks are evaluated as alternative strategiesfor implementing holonic control for a modular feeder subsystem of anexperimental Reconfigurable Assembly System. The strategies are evaluatedthrough four reconfiguration experiments. The evaluation is based onqualitative and quantitative performance measures. The results show thatagent-based control is more suitable in this specific case study.