Research On Edge Safety Node Of Train Control Safety Computer Platform Based On Cloud Computing

With the further application of cloud computing technology in the next generation train operation control system,the train control safety computer gradually develops from independent structure to integration and modularization,and the safety computer platform based on cloud computing gradually becomes the mainstream development trend.The rail transit industry has put forward higher requirements for the computing capability,safety and reliability of train operation control equipment.The application of cloud computing technology in the rail transit industry has greatly reduced the number of equipment,but it still faces many safety problems.Combining cloud computing with train control safety computers,adopting appropriate mechanisms to meet the growing computing needs of the rail transit industry and realizing safety functions are practical problems that need to be solved.Therefore,this paper aims at safety,and ensures the security of cloud computing platform through the design and implementation of edge safety nodes,so that it can meet the SIL-4 safety index.Firstly,based on the analysis of the safety principle and safety analysis methods,combining the factors such as feedback mechanism and common cause failure,the existing reliability block diagram method of IEC61508 safety standard and other safety analysis methods are compared and analyzed,and several basic redundant structures such as 2oo2 and 2oo3 are studied.Considering the feedback mechanism and other factors,Considering the feedback mechanism and other factors,the dynamic Bayesian method with time segment was innovatively adopted to verify that the dynamic Bayesian method is equivalent to the reliability block diagram method.Secondly,starting from the characteristics and requirements of secure computers based on private clouds,since ordinary cloud computing services are untrusted computing environments,edge safety nodes are set between local devices in secure domain and cloud computing devices in non-secure domain,and the two devices are isolated to delimit the safety boundary.At the same time,the functions of edge safety nodes are designed,including basic input and output functions,time monitoring functions,logic monitoring functions,computing power monitoring functions,and the design of Byzantine voting algorithm.Then,according to the hardware selection of the relevant components needed by the edge safety node,the edge safety node architecture with high safety performance is designed according to the safety redundancy structure recommended by IEC61508 safety standard combined with dynamic Bayesian method.Because the cloud computing platform is facing a complex internal and external environment,this paper sets the parameters of the theoretical model,and through theoretical analysis and quantitative analysis of mathematical expressions,it is concluded that the setting of edge safety nodes and the existence of Byzantine voting algorithm reduce the information security risks faced by the cloud computing platform.Based on the above theoretical analysis on the function design,algorithm design,architecture design and risk analysis of cloud computing platform and edge safety nodes,it is proved that they meet the SIL-4 safety index,and the rationality of setting edge safety nodes and Byzantine voting algorithm design is verified.Then,through the understanding of the model,the PCB hardware schematic diagram of the motherboard of the edge safety node is drawn and the hardware circuit board is made.Finally,according to the construction principle of the experimental platform,the experimental platform is built,and finally the edge safety node communicates with the cloud computing platform and the object controller through the switch.The whole structure of the edge safety node and its control system for cloud computing devices and object controller described in this paper is implemented and verified.There are 50 pictures,15 tables and 81 references.