Dynamic parameter estimation of pressure transducer in shock tube calibration test

Abstract

Shock tube is the key device in the pressure transducer dynamic calibration. But as the output of pressure transducer often contains strong interference,which makes it difficult to directly use the output to build the dynamic model of calibrated pressure transducer,in addition,the accuracy of the model is hard to be characterized. A parameter estimation method was proposed which could be applied to pressure transducer in shock tube calibration test. Firstly,the operation of information generation was employed to process the output of calibrated pressure transducer under the pressure of step excitation,and then estimated sequences,upper boundary and lower boundary were obtained. Secondly,the processing methods about filtering and modeling were used to deal with the estimated sequences,upper and lower boundary,and then we could obtain the best estimated value model,the upper boundary model and the lower boundary model. Finally,by solving the obtained models,the indicators obtained by the best estimated model was the best characteristic indicator of the calibrated transducer,the indicators obtained by upper and lower boundary model could compose confidence interval of best indicators,it could show the reliability of the best indicators. A calibration test of shock tube is conducted with the piezoresistive pressure transducer of Endevco 200 series type. The relative errors of dynamic indices of time-domain are no more than 8. 17%; the relative errors of dynamic indices of frequency-domain are no more than 9. 15%. All the obtained indicators fall in the estimated interval with 100% probability of reliability.