A Poppet Magnetic Localization Method for the Ultraclean Electric Valve Based on Combined Integral and Fitting Model

With the increasing need for ultraclean liquid transportation in the integrated circuit manufacturing field, the ultraclean electric valve has been developed to realize contactless poppet control through the magnetic field excited by the embedded permanent magnet (PM). To achieve high precision control of valve poppet displacement, a magnetic localization method is proposed for the valve poppet position detection. A combined integral and fitting model is derived to describe the magnetic field of poppet PM and control PM individually, considering various geometry characteristics. Based on the combined integral and fitting model, poppet position detection is turned into an inverse magnetic problem of the marked poppet PM, which is solved by the Levenberg-Marquardt (LM) algorithm. The feasibility of the magnetic field model and the solvability of the LM algorithm with different initial value determination criteria are analyzed based on simulation. The effectiveness and accuracy of the proposed poppet magnetic localization system are verified by both multiphysics field coupling simulation and experiments based on a developed hydraulic test system. Aeries of experiments were carried out, with the absolute errors of static localization range in [0.012, 0.351] mm with the maximum relative error of 0.35%. For dynamic localization with three drive speeds under no load, the absolute errors range in [−0.314, 0.371], [−0.345, 0.378], and [−0.345, 0.378] mm with mean relative errors of 0.51%, 0.6%, and 0.61%, respectively; for on-load condition, the localization errors range in [−0.379, 0.401], [−0.409, 0.406], and [−0.424, 0.434] mm, with mean relative errors of 0.61%, 0.74%, and 0.70%, respectively.