Fault diagnosis of liquid rocket engine thrust chamber based on improved augmented particle filter

The fault diagnosis algorithm proposed in this paper firstly establishes the nonlinear thermodynamic model of the thrust chamber of the liquid rocket engine under normal mode and four common fault modes. Secondly, the particle filter is designed to estimate the output and residuals of the thrust chamber and complete the fault detection task by using the generalized likelihood ratio test method. Thirdly, an extended fault estimation particle filter is established by merging the fault estimation vector into the extended state estimation vector to complete the task of fault estimation. Finally, a fault recognition algorithm is designed according to the fault estimation result to complete the fault recognition task in the case of a single fault, at the same time, the recognition result is used to improve the accuracy of the enhanced particle filter. The proposed method is verified to realize real-time and accurate fault diagnosis of thrust chamber under the influence of uncertain factors such as process and measurement noise.