A two-stage servo feed controller of micro-EDM based on interval type-2 fuzzy logic

摘要

In order to improve the performance of micro-electrical discharge machining (micro-EDM), the most important issue is to develop a highly stable servo control system. In order to account for the characteristics of high frequency, serious signal distortion, and high noise in micro-EDM process, type-2 fuzzy logic sets are introduced which is able to handle these uncertainties effectively. Based on interval type-2 fuzzy sets theory, a two-stage servo feed controller is designed. The first stage of the controller is for detecting the discharge state for a single sample point, and the second stage is used to obtain the servo feed speed. In addition, the discrimination and statistical methods for discharge states of sample points are proposed to obtain the proportion of each discharge state in an analytical period. Experiments demonstrate that the new controller can obviously improve the processing efficiency of micro-EDM compared with traditional controllers. Therefore, the proposed interval type-2 fuzzy logic-based two-stage servo feed controller is an effective way to enhance the efficiency and stability of micro-EDM and meanwhile to achieve good processing quality.