Research And Application Of Safety Computer

Safety computer system,which can realize the Fail-safe in the case of failure,Fail-safe means the output of the system lead to the safe side when in a state of failure,such as turn off the signal,output braking etc.The aim is to avoid significant loss of life and property.Safety computer is widely used in aerospace,chemical industry,rail transportation,nuclear power and other safety critical areas and it should have the ability of stable and reliable operation for a long time and the ability of dealing with major disasters.At present,the safety computers used in railway traffic control are mainly mature products from foreign manufacturers.Therefore,it is very important and urgent to develop a safety computer platform with completely independent intellectual property rights.In this paper the working strategies,the advantages and disadvantages of three typical safety computer architectures are analyzed.The related concepts and safety design principles of safety computer are introduced.From the point of view of hardware and software,the paper focuses on the computer security technology,including fault detection,synchronization mechanism,master-standby switching,voting and security output.For further improving safety and reliability of safety computer system,the double 2-out-of-2 with new degradation is put forwarded,which compromises the merits of the traditional double 2-out-of-2 and 2-out-of-3,and its overall architecture are given.The hardware and software implementation method of synchronization and voting under the new degradation are designed.To analyze and verify the safety and reliability of the new degradation strategy of double 2-out-of-2 system,the work status of traditional strategy and new degradation strategy are classified,and Markov state transfer model is established base on the transformation principle between each working state.The safety and reliability of two kinds of strategies are analyzed by simulation with MATLAB.Simulation results show that compared with the traditional degradation,the double 2-out-of-2 with new degradation has higher reliability.The new degradation strategy of double 2-out-of-2 system presented in this paper has realization condition in software and hardware.An axle counting systems with double 2-out-of-2 architecture based on ARM was designed and implemented.The hardware framework and the pin definition of the board are given explicitly and the design of system are expounded by view of software function and communication modes.Finally,capture functional test of axle-counter,master-standby switching functional test and synchronization functional test of intersystem and intrasystem have been designed and tested.