Hierarchisch kaskadierte Fuzzy-Prozessführung für Prozesse mit stark variierenden Zeitkonstanten

Abstract

Electro-Discharge Machining stands for high accuracy and very sophisticated metal shaping. The physical process takes advantage of electric field effects between two electrodes. In the so-called erosion gap that contains dielectric fluid high voltage sequences of pulses are generated. These pulses remove metal form the workpiece (negative poled electrode) through melting and vaporisation processes. Among other sources the electrically efficient gap width which consists of the electric conductivity and the geometrical distance of the electrodes varies from spark to spark. This variation leads to an overall highly non-linear control problem. Furthermore the reaction time on the gap variation imposes hard timing constraints on the process control system. In order to master this control duty we have developed a hierarchical cascaded fuzzy optimization system for EDM sinking process control. This integral fuzzy control concept combines high-speed process control and ‘on-line’ process parameter optimization. A well-adapted hardware system for EDM process control builds the basis for accurate parameter sensoring, high-speed data processing and rapid control command elaboration. The system has already proved its reliability and capability partly in simulation and partly under real working conditions. Finally a special Fuzzy-Hardware will be presented that supports high-speed fuzzy calculations in a multi-processor environment.