Development of a Monitoring and Control System for Wire Electrical Turning Process

• Main Authors: Hsieh, PaiHung, 謝百閎
• Other Authors: Yan, MuTian
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/06934467361599867269

碩士 === 華梵大學 === 機電工程學系博碩專班 === 101 === This paper presents a new pulse discriminating and adaptive control system for process monitoring and control of wire electrical discharge turning (WEDT) process. The pulse discriminating device including a spark gap monitor and a digital signal processor (DSP) card has been developed to identify spark gap states and compute ignition delay time. The relation between the proportion of open circuit, normal spark, arc discharge, short circuit in the total sparks (defined as open circuit ratio, normal spark ratio, arc discharge ratio and short circuit ratio, respectively), ignition delay time and metal removal rate were experimentally investigated during the WEDT process. Through pulse train analysis, arc discharge ratio and ignition delay time can be used as sensing parameters for process monitoring and control. For cylindrical wire electrical discharge turning process, machining feedrate is adjusted by servo feed control to keep forward sparking gap at a proper width. However, the servo feed control system fails to respond to the variation of lateral gap width due to a constant spindle speed. A fuzzy logic controller is designed to control both the arc discharge ratio and ignition delay time at a predetermined level through an on-line regulation of federate and pulse off-time for adaptive process control. Experimental results show that the developed adaptive control system results in faster machining and better machining stability than does a conventional control scheme for the WEDT process.