IMPLEMENTATION OF FORECASTING COMPENSATORY CONTROL FOR MACHINING STRAIGHTNESS.

This paper aims to achieve higher machining form accuracy through an approach called Forecasting Compensatory Control (FCC). Through stochastic modeling, the errors are represented by a model of simple structure, in which both repeatable and nonrepeatable components of the error are accounted for while optimum forecasting compensates for the time delays associated with measurement and control. An algorithm for straightness control has been proposed, making use of direct measurements of workpiece straightness, and of a recursive parameter estimation algorithm. The proposed strategy was implemented through the development of a laser in-process straightness measurement system, a precision hydraulic positioning system and a digital microcomputer system. Finally, online cutting experiments were carried out in an end-milling operation. The experiments demonstrated that workpiece straightness can be improved up to 80%, confirming the effectiveness of the proposed algorithm.