(A) study on the adaptive control system for turning process using cutting temperature

Abstract

The Study is concerned with adaptive control of CNC lathe by sensing on-line cutting temperature. Adaptive control system requires the definition of both a performance index and a mathematical model for the process. In order to obtain a performance index and a mathematical model for turning process, cutting temperature and flank wear are measured. Cutting temperature is sensed on-line using the tool/workpiece thermocouple technique and flank wear are measured off-line at regular intervals. Optimum input parameters (feed and cutting speed), optimum process parameter (cutting temperature) and maximum performance index are searched by steepest ascent procedure under given constraints. As a result of simulation, minimum cost is obtained by using maximum allowable feed. Therefore the optimum cutting condition may be achieved by varying a single parameter (cutting speed) for turning process. Adaptive control system increases the productivity about 9% and optimum cutting temperature control system increases it about 8% at constant depth of cut, and optimum cutting temperature control system can be constructed simply and inexpensively. Therefore, in industry, it is recommended to use optimum cutting temperature control system, which is the simplest adaptive control system.