Fuzzy logic based controller for micro-electro discharge machining servo systems

Abstract

In this paper, a tunable fuzzy logic based servo controller for monitoring and control of the micro-electro discharge machining (micro-EDM) process has been developed, which uses the behavior of discharge pulses. The fuzzy logic applies a heuristic approach in dealing with the non-linear and time varying nature of the micro-EDM process. The control parameters affecting the performance of micro-EDM include gap voltage and gap current discharge pulses. It is important to discriminate between different levels of pulses for proper operation of micro-EDM. Discrimination of pulses from an Retype power source is still an ill-defined problem relying on heuristics. The choice of appropriate values of discharge pulses is generally based on the knowledge and experiences of operators. In this study experiments were carried out to distinguish the discharge pulses, which were then classified into open, sparking, arcing, off and short circuit. The classified pulses were utilized as the input fuzzy sets of the fuzzy logic based controller that drives the servo system to maintain the desired gap width. The simulated results obtained demonstrate that the fuzzy logic controller is able to provide stable machining and improve the performance of the micro-EDM process.