Research On Determination Of Calibration Intervals For Automatic Test System And Its Measuring Instruments

Measuring instrument is an important part of Automatic Test System,with strong demand of various industries and the the development of science and technology, test equipment is becoming more and more complex, toward a modular and open direction, leaving little historical calibration data, The traditional method for determining measuring instrument’s calibration interval is no longer applicable. The grey system theory is one of the most active three emerging uncertainty system theory,it is applicable to study "little data" or "poor information" uncertain systems. In this thesis, the grey GM(1,1) theory is applied to the determination of calibration interval for test equipment, and an improved gray prediction model and a new system-level calibration interval forecasting method based on weighted scoring method is built.For GM(1,1) model prediction accuracy is low on account of itself defect, the automatic optimal weighting method and least squares is used to improve the model itself, and in order to make GM(1,1) model can be better used for medium or long-term prediction, gray dynamic forecasting method is used combining the advantage of dynamic update information., in order to further improve the prediction accuracy, the final residual error correction is carried out,which imports Markov process to determine the plus or minus of residual error. Through Matlab simulation,examples verify the effectiveness of the improved algorithm, and the prediction precision is obviously improved.This thesis analyzes and summarizes the ATS measurability related modeling theory research,and its combination with the weighted average method is introduced in detail to determine the calibration interval of ATS. On the basis of ATS hardware component to determine the internal measurement chain, then multi signal flow graph modeling is built, and all single measurement contribution rates which are used as the weight are calculated after model analysis, finally weight average of all measuring instruments calibration cycle to obtain the calibration interval of the whole system. In order to ensure all the measuring instrument in the calibration interval not exceed theerror range, for single calibration interval less than system calibration interval of individual instruments can be measured by other inter instrument ranking higher. So the ATS as a whole to define a calibration can make it simple for calibration, and can avoid demolition and other difficulties. This method is scientific, convenient, and has certain reference value for other systems to determine its calibration interval.