Modelling and adaptive control of the wire transport system in wire electrical discharge machining

Abstract

Accurate control of the tension of a wire electrode is a requirement of a machine for wire electrical discharge machining. In this paper, a closed-loop wire feed and wire tension control system is presented to guarantee smooth wire transport and a constant tension value. The dynamic model and system identification of the wire transport system is derived to analyse and design the control system. A one-step-ahead adaptive controller is proposed to investigate the dynamic performance of the closed-loop wire tension control system. This control scheme can ensure a stable closed-loop system. Experimental results demonstrate that the proposed adaptive controller can obtain a faster transient response and a smaller steady state error than a PI (proportional-integral) controller.