Research On Fault Injection And Fault Diagnosis For Electro-Mechanical Systems Of Civil Aircraft

With the rapid development of aviation industry technology and the modernization and large-scale of civil aircraft,the complexity of electro-mechanical systems of civil aircraft increases quickly.During system usage,various failures happen.The traditional periodic maintenance and routine inspections are mostly remedies for faults that have occurred,with low efficiency,poor real-time performance,and strong subjectivity,which are increasingly unable to meet system security requirements.Meanwhile,with the increasing complexity of airborne electro-mechanical system,compared with the problems of low quality,long period and high cost existing in traditional text-based system engineering,model-based system engineering(MBSE)has become a hot topic in research and application of complex system design at home and abroad.In view of above-mentioned problems,this paper studies on fault injection and diagnosis of typical electro-mechanical systems(landing gear system and environment control system)designed by MBSE.By the design of fault diagnosis,real-time online detection of system is achieved.According to the diagnosis results,fault tolerance mechanism(hardware redundancy)of the system is designed,too.Then,fault injection is used to verify the design of fault diagnosis and fault tolerance mechanism.First of all,simulation-implemented fault injection is adopted and a fault injection module is designed to inject typical faults(stuck,drift and failure)into system model in design phase.Then,the fault diagnosis methods adopted in this paper(fault diagnosis observer and BP neural network)are introduced.And,the process ofmodeling of system SysML model and Rhapsody/Simulink co-simulation are studied.Secondly,mathematical models of landing gear steering control system,landing gear anti-skid brake control system,cabin temperature control system and cabin pressure control system are established respectively.The common faults of the system are analyzed,and the designed fault injection module is used to realize the corresponding fault injection.Then fault diagnosis observer and BP neural network are used to diagnose linear system and nonlinear system respectively.And the designed fault diagnosises are verified in Simulink.Thirdly,the design and verification of fault injection and diagnosis of landing gear system and environmental control system are completed in Rhapsody.Using MBSE,combined with the completed studies on fault injection,modeling and fault diagnosis,the SysML models of fault tolerance mechanism of landing gear system and environment control system including fault injection and diagnosis functions are established,and the panel diagrams are designed in Rhapsody for verification.At last,the fault injection and simulation software of electro-mechanical systems of civil aircraft is designed.By using the simulation software,the operational controls of system SysML model and fault injection setting are realized,and the state of system and fault diagnosis result are displayed in various ways such as curve,text and instrument.