The Research Of The Action Characteristic Of The Electromagnetic Valve Based On Non-contact Measurement

In recent years, direct acting electromagnetic valve is gradually applied to aerospace,aviation, petrochemical and other kinds of control system because of its simple structure, smallsize, high response speed, good stability and so on. As switch actuator of the control system,the electromagnetic valve must repeat to start working and carry on pulse operation when thesystem run. So it is very important to grasp the switching time of the electromagnetic valve.This design obtains the main operation characteristics of the electromagnetic valve byanalyzing the electromagnetic valve model. The design uses non-contact inductive coilsmagnetometer to carry on A/D sampling and analyze the sampling data. The electromagneticvalve move fast and the amount of sampling is huge while the electromagnetic signal is weak.For sampling the signal accurately, the design uses the instrumentation amplifier INA118toamplify the signal, and then make use of A/D module to sample the signal. Electromagneticinterference is complex from surrounding environment and acquisition system, and bring theinevitable noise. The electromagnetic noise need to amplifying and sampling while amplifyingand sampling useful signal. As the switching time of electromagnetic valve is short, using thesampled signal with the noise to judge switching time of the electromagnetic valve will causedeviation. In order to determine the accurate switching time of the electromagnetic valve, thesignal that is amplified and sampled by electromagnetic coil sensors need to digitize. Thisdesign is based on the normalized LMS for adaptive filtration noise cancellation signal byanalysis and comparison of a variety of adaptive filtration algorithm. This article summarizesthe basic principles, structures and applications of the adaptive filtration and in-depth study onthe Least Mean Square algorithm of the adaptive algorithm.This article analyzes their convergence properties and the effect of parameters on theperformance of the algorithm, and compares the performance of the algorithm. By making useof the MATLAB software, the article makes a simulation research on the adaptive algorithm inthe noise cancellation. For all kinds of different parameters and different input signals, this article analyzes and compares filtration convergence speed, steady-state error and theadvantages and disadvantages of each algorithm for various circumstances. The adaptivefiltration algorithm effectively eliminates the noise when sampling the weak electromagneticsignals, and realizes a precise estimate of the switching time of the electromagnetic valve.