Research On Requirements Modeling And Validation Of Integrated Modular Avionics System

Integration and modularity are both major development directions of avionics system.Originating from application partitioning,IMA system shares and reuses function-independent components to build open and modular avionics.The System model is designed based on functional requirements and developers obtain suggestions for improving the model by means of validating whether it satisfies certain performance requirements.However,requirement validation is faced with some problems.For one thing,graphically modeling and conveniently analyzing cannot be both satisfied;for another,the validation results are not always fed back to system design in time.Thus,focusing on reliability and timeliness requirements of IMA system,the research proposes a new method for modeling and validation of IMA system requirements based on modeling languages(e.g.SysML,AADL etc.).The paper work can be summarized as follows:(1)Aiming at the problem that failure modes and propagations are hard to describe and analysis,a method for reliability requirement validation by extending FMEA is proposed.Based on in-depth study of components' inner failure modes and mutual propagations,the research upgrades the traditional FMEA and attaches it to system architecture model to establish the reliability model.Then an algorithm is proposed to automatically transform the reliability model into a proposed weighted failure propagation graph.Eventually,the system reliability can be evaluated along with failure rates of its components.(2)Aiming at the difficulty of obtaining time delay in the initial design phase,a method for system timeliness requirement validation is proposed.A system/component activity model with time constraints is designed with nonfunctional property descriptions of MARTE.A mode transition protocol is defined by introducing mode transition mechanism of AADL,based on which we can acquire time delay of the system.In order to analysis the models automatically,an XML-based model transformation from SysML/MARTE to AADL is discussed.Finally,the model timeliness is validated with the analysis tool set.(3)A system of IMA safety and timeliness requirement validation is designed and implemented.The system provides IMA system developers with a handy platform for system model design and requirement validation,which significantly improves development efficiency and helps to ensure that the product meets the requirement of all stakeholders.