Simulation Of Steam-powered Catapult Process And Fault Signature Analysis

The steam-powered catapult is the pivotal device of ensuring Aircraft Carrier’s fighting ability, However, our country is far behind America and Britian in manufacture and monitoring technology of steam catapult. The domestic researches on steam catapult are most about catapult system design, there are very few about steam catapult condition monitoring and fault diagnosis, but these technology is very significative on guaranteeing catapult operate normally, avioding catapult accident and ensuring the security of aviator and aircraft. Therefore, this text takes the main parts of steam catapult system which involved in steam catapult process as research objects, uses the mean of simulation to study the fault signature of steam catapult system, and lay a foundation for condition assassment and fault diagnosis of steam catapult.In oeder to achieve the above research purpose, in this text first to study the theory of steam catapult process and establish every part’s mathematical model, they are the model of steam wet accumulator, the model of lauching engine cylinder, the dynamic model of aircraft, the model of lauch valve hydraulic control system and the model of steam flowing through lauch valve. In addition, through transforming these mathematical model and combining some corrosponding numerical methods, estabish the simulation model of each part in MATLAB. On this basis, according to the relationship of information transmitting between each part, establish the whole simulation medel of steam catapult process. And verify the rationality of the mode by comparing the simulation data with the test data in MIL. Finally, get the normal monitoring datas of steam catapult through simulate the normal condition.Because the monitoring datas contain the health information of catapult system, the fault signature analysis of steam catapult is based on these datas. In order to extract the system health information from the discrete and abstract monitoring datas, we need to discribe these datas in forms of mathematics. So, through analysis these normal simulation datas, found that they are all in forms of trendency without fast vibration, we establish the change model of each data by curve-fitting method. In this way we estract the system health information from the monitoring data and put it into these change models. The parameters of these models will change when steam catapult system malfunction.Finally simulate two kind of fault: the internal leakage of hydraulic cylinder and the lauching engine cylinder piston resistance enlarge fault, and get the fault datas. Through comparing the normal data and fault data, extract the feature of each fault, and chose the fault feature parameters by analyzing the tendency of monitoring data model parameters change with the fault degree. What’s more, analyze the other influence to catapult process of each fault.