Design And Validation Of Safe Computer Platform Based On Model Engineering

Safety-critical systems are widely used in the railway, aerospace, industrial control applications and other areas. The development of safe computer technology, which has formed a special branch of science, is paid more and more attention to. In order to expand the scope of application, reduce development costs and maintenance cost, safe computer technology develops towards generic, upgradeable, extensible direction, etc.The application background of this paper is Data Storage Unit and Zone Controller of Communication-Based Train Control system. The paper has researched a system developing method based on Model Engineering, which is used in the design of safe computer platform. The design uses combination of hardware and software redundant.The paper introduces the concept of Model Engineering which is based on formal methed. In Model Engineering developing methed, modeling and verification for system can be done at the beginning of system development as well as the whole development life cycle. So it can realize early detection of design problems. Architecture Analysis and Design Language is a formal modeling language supporting Model Engineering. The system needs analysis, system level modeling, platform software process modeling and model validation has made to the CBTC safe computer platform based on system development life cycle.Based on demand analysis of safe computer platform in CBTC, high-level AADL model of the safe computer platform has been designed, and the detailed architecture of the triple module redundancy safe computer platform has been described. The architecture consists of application software, platform software, processor and specialized hardware redundant management modules (RM). The working principle of safe computer platform and the logic function of RM hardware unit have been described.The platform software process has been described in detail. According to the process, the AADL model of platform software has been designed. The model includes system voting module, system reconstruction module, system transformation module etc. According to the needs of CBTC safe computer platform, the paper has verified safety level, real-time response and schedulability of AADL system using OSATE. The result has proved the good reasonableness and correctness of the design. The production and testing of extensible safe prototype computer proves to be successful. It also shows the correctness and feasibility of the system design. At the same time, it proves that the method of model engineering developing based on modeling and verification is suitable for the design of safe computer platform.