Kun Liu, Xiaoyu Chi, Jiayi Wang, Yuanhua Xie, Xiaohao Li, Northeastern University, Liaoning, China
Following the development trend of intelligent instruments in the era of Industry 4.0, the demand for high-precision measurements for scientific research and industrial production sites has become more prominent, and vacuum measuring instruments are moving towards intelligent composite and metrology-measurement function integration. At present, the metrological calibration of vacuum measuring instruments is still based on manual calibration, which has problems such as delayed delivery and leads to inaccurate measurement results. The development of capacitive, magnetic levitation rotor type and ionization type three principles of composite wide-range vacuum measuring instrument, in order to meet the 10^-9~10⁵Pa range of measurement needs, at the same time, to solve the traditional measurement process of measurement uncertainty superposition caused by the transmission of the value of the instrument in-situ real-time metrology and accurate measurement. Taking the magnetic levitation rotor vacuum sensing component “standard apparatus” as the core, we set up the overlapping area of its measurement range with capacitive and ionization sensors to carry out the “self-calibration” metrology research. Based on the changing law of the adaptation coefficient of the magnetic levitation rotor vacuum sensing assembly in the cross-flow conditions, taking into account the temperature-pressure effect of different flow conditions, cluster analysis of capacitance, current, voltage and other signals, and the establishment of self-calibration theoretical model. Based on the intelligent self-calibration software to screen and judge the instrument calibration coefficients that change over time, independently select RANSAN and other fitting correction methods, search for optimal iteration, construct a standard pressure model, obtain a wide-range, high linearity output characteristic curve, and ultimately realize the measurement of self-calibration and high-precision inversion of the pressure signal.