Fault Diagnosis of Liquid Rocket Engine Based on Unscented Kalman Filter
A liquid rocket engine fault diagnosis algorithm based on unscented Kalman filter(UKF)was designed.To address the problem that it is difficult to obtain rocket engine fault data,a liquid rocket engine fault simulation model was built using MATLAB/Simulink platform,which realized the engine normal operation simulation and three kinds of fault simulation,including the oxygen valve failure in the pre-combustion chamber,the vapor corrosion of the oxygen main pump,and the de-tachment of the hydrogen main turbine blades.The normal operation simulation values were com-pared with the design values and the test run values.The results showed that the maximum error be-tween the model parameters and the design value was not more than 5%,the simulation accuracy was high,the simulation parameter change trend was basically consistent with the test value,and the error of the steady state value was small.Finally,the UKF algorithm was used to find the engine normal operation threshold range and to filter the fault sequence.If the fault data exceeded the threshold interval for three consecutive times and at least two turbopumps alarmed within 0.1 s,the fault was determined to have occurred and the time of fault occurrence was the time of the second turbopump alarm.Using the designed algorithm to diagnose the three fault sequences,it was deter-mined that the fault occurrence time was 20.08 s,20.05 s,and 20.18 s,respectively.Compared with the traditional red line threshold algorithm,the proposed algorithm has more timely response and lower false alarm rate.
fault diagnosisliquid rocket engineunscented Kalman filterfault simulationred line thresholding algorithm
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