Fmeca And Fta-based Unmanned Aircraft Taking Off And Landing System Reliability Study

Landing System, as one of the key components of the aircraft, has been playing an important role in ensuring the safety of flight and landing. Reliability is the protection for the product quality and safety throughout the entire product life cycle.There is a shortage of comprehensive analysis of the total system in the study of the landing system reliability. Based on the project, the reliability analysis system is given. By combining FMECA (Failure Modes, Effect and Criticality Analysis) with FTA (Fault Tree Analysis) and FRACAS (Failure Reprorting, Analysis and Corrective Action System), and utilizing of the information flow, the objective of combining the analysis and design, the formation of closed-loop quality management system and reducing the failure rate is achieved.In order to improve the fault information system, this thesis analyzes the FMEA of the landing system; get the information of the failure mode. In order to get the comprehensive risk assessment of the landing system, the fuzzy comprehensive evaluation is introduced and the risk assessment model is set up. First of all, each subsystem of the landing system is analyzed, AHP is used to get the evaluation index weights, and then the evaluation matrix is used to get the fuzzy risk assessment vector. By using the center of gravity method, the fuzzy vector is processed clearly. The evaluation level of each system is given and the results are analyzed according to the FMECA evaluation criteria in the end. The evaluation model of the whole landing system is set up and the system risk rate is given based on the analysis of the subsystems. Then, according to the risk analysis, the comprehensive CA model which is based on the fuzzy comprehensive evaluation is set up. The comprehensive hazard degree analysis of all the failure modes is done and sorted by grade.Based on the analyzing the FMECA, the method of FMECA analysis which is assisted by FTA is given. Utilizing the FTA, the failure mode which severities is I and II is analyzed, and the fault tree is analyzed.The basic content and implementation method of 3F work system is discussed. Based on the FMECA and FTA, FRACAS is used to analyze the system, the example is analyzed by using the exiting data, the result of the fault analysis is exported, the method is corrected, and the information feedback is sent.