Research Of Error Acquisition And Parameter Identification For NC Machine Tool Based On Virtual Instrument

With full progress of production process automation and wide application of precision machining, the machining accuracy requisition for NC machine tool is increasing day by day. Flexible manufacturing system (FMS) and flexible manufacturing unit (FMC) has put forward higher demand to automatic monitoring and compensation of various kinds of error in the process course of NC machine tools. At present, the measuring, showing and monitoring of the errors have already become the bottleneck question of machining especially that of precision machining and ultra-precision machining.This paper is on the foundation of current domestic and international using situation of error element modeling technology, error measurement technology and compensation control technology of NC machine tool with full understanding and analyzing. According to different properties of error elements, the error elements of NC machine tool are analyzed and classified. Research on the methods of geometric error parameter identification and error compensation of NC machine tool has been carried mainly in this paper.The precision of NC machine tool itself is the key point that determines to machining efficiency and precision, and simulation is an effective way of verifying inspecting path. In this paper, basing on profound analysis of error parameter identification and error compensation method and aiming at twenty-one geometric errors, the error data acquisition is controlled by Virtual Instrument and the functions of error parameter identification, error compensation, error remote panel monitoring and simulation validation are realized. Utilizing object-oriented virtual compensation technology, a virtual error compensation system for NC machine tool that is programming rational, convenient and powerful has been developed with LabVIEW andMATLAB platform. According to software testing theory, the effective testing for virtual error compensation system proves its rationality, currency and expansion, which can meet the compensation command of files of machining and inspection programs according to different machine tools and different parts.The research contents of this thesis are as follows:1) The general planing, composing and realizing of software and hardware of geometric error data acquisition system of NC machine tool.2) Research on error modeling technology based on the interface of LabVIEW and MATLAB and the realization of programable modeling.3) Research on error parameter identification technology based on LabVIEW.4) Research on error compensation technology based on LabVIEW. Through example simulation, the correction of error compensation model and availability of error compensation method are verified for NC machine tool.5) With the direction of some basic theory for the object-oriented software testing technology, the effective testing for virtual error compensation system has been done.