Leak fault detection of liquid rocket engine based on strong tracking filter

The propellant leak is one of the most common and especially dangerous faults in liquid rocket engine (LRE). By analyzing the performance of the engine, we know that the leak of hydraulic lines can be expressed as the variation of the fluid resistance coefficients. If leaks occur in the hydraulic line, the corresponding fluid resistance coefficients will be changed. An approach is presented to detect and diagnose the leak of hydraulic line based on a strong tracking filter. The method uses a strong tracking filter to estimate the fluid resistance coefficients and to compare the estimated fluid resistance coefficients with their normal values. Then the modified bias method is used to detect the leak fault. We simulate the leaks occurring in the main system or in the subsidiary system of LRE. The results show that the approach is feasible.