A Real-time Fault Detection And Post-test Diagnosis System For Liquid-propellant Rocket Engines In Ground Tests

Paper number

IAC-07-C4.I.09

Author

Dr. Jianjun Wu, National University of Defense Technology, China

Year

2007

Abstract

Health monitoring is an important approach to improve the safety and reliability of Liquid-propellant Rocket Engines(LRE). However, there are still several critical problems to be solved in the on-line and real-time health monitoring of engines such as the in-time and precise detection of faults, the real-time and quick acquisition, conditioning, transporting and saving of metrical data, the ability of avoiding from giving false alarms, and so on. In this paper a real-time fault detection and post-test diagnosis system for LRE in ground tests is presented.
Firstly, the synchronous combination of real-time fault detection and data recording of various signals is achieved based on the technology of testing bus and virtual instrument. Moreover, the system is founded on a distributed local network, where the data acquisition, fault detection, data analysis and display are distributed to several computers and so the reliability and efficiency of the system is improved.
Secondly, the health monitoring software system is modularized and decomposed into five modules such as the controlling, database, data acquisition, fault detection and analysis, and auxiliary functional module. Moreover, the simulation of functional interfaces to engines, recurrence of faults in the way of playback with test data, verification of the performance for fault detection methods, management such as the query and analysis of the measured data, alerting and fault information are also proposed.
Thirdly, several real-time fault detection methods such as the Redline, EA (Envelope Algorithm),ACA (Adaptive Correlation Algorithm),ATA (Adaptive Threshold Algorithm),BP(Back Propagation) and RBF(Radial Basis Function) method are developed, and then an integrated decision-making method is proposed, where the above fault detection methods are all utilized and integrated into the system to make a final decision. 
The system has not only been tested with a large amount of test-fire data in laboratory, and also it has been verified and validated in several actual ground tests of engines. Results show that the system is able to monitor the whole working process of engines in a real-time manner, and its performance satisfies the scheduled requirements such as the reliability, the rate of false alarm, and so on. It has been the first practical health monitoring system that can be used in the ground tests of LRE in China. It can not only be used in the real-time fault detection and post-test diagnosis of all currently used engines in ground tests, and also it provides important technical basis for the development of the on-launch health monitoring system.

Abstract document

IAC-07-C4.I.09.pdf

Manuscript document

IAC-07-C4.I.09.pdf (🔒 authorized access only).

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