异构三重冗余控制系统的设计与可靠性评估

Designand Reliability Evaluation of Heterogeneous Triple Modular Redundant System

针对传统的PLC三重冗余系统存在的共因失效问题,提出了一种异构的PLC三重冗余容错方案。系统采用OMRONCS1D、SIEMENSS7-400和ROCKWELLControllogix三个不同的PLC构成主处理器的三重化冗余,对输入、输出模块也进行了异构的冗余化设计。利用表决和表决自适应机制对冗余数据进行处理,并设计了一套适用于异构冗余的软硬件结合的检测机制。在考虑共因失效的条件下建立了系统的马尔科夫可靠性模型,利用MATLAB对其进行了可用度和可靠度仿真。仿真结果证实了异构冗余的方案能有效提高三重冗余系统的可靠性。

For conventional PLC triple modular redundant （TMR） systemsexists common cause failure （CCF） issue, a PLC heterogeneous triple modular redundant fault-tolerant scheme is presented in this paper. In this scheme, the main controller subsystem is designed in TMR structure with three different PLCs： OMRON CS1D, SIEMENS S7-400 and ROCKWELL Controllogix, the input subsystem, output subsystemand system bus arealso in heterogeneous redundant structure.The redundant data is processed in majority voting system and adopting preset adaptable voting mechanism. A self-diagnostics mechanism support heterogeneous TMR structure is presented to realize fault processing. Taking into account of CCF, availability and reliability of the system are analyzed based on the Markov model. Simulation results show that the heterogeneous redundant can improve reliability effectively.